Analysis of ischaemic crisis using the informational causal entropy-complexity plane.

In the present work, an ischaemic process, mainly focused on the reperfusion stage, is studied using the informational causal entropy-complexity plane. Ischaemic wall behavior under this condition was analyzed through wall thickness and ventricular pressure variations, acquired during an obstructive flow maneuver performed on left coronary arteries of surgically instrumented animals. Basically, the induction of ischaemia depends on the temporary occlusion of left circumflex coronary artery (which supplies blood to the posterior left ventricular wall) that lasts for a few seconds. Normal perfusion of the wall was then reestablished while the anterior ventricular wall remained adequately perfused during the entire maneuver. The obtained results showed that system dynamics could be effectively described by entropy-complexity loops, in both abnormally and well perfused walls. These results could contribute to making an objective indicator of the recovery heart tissues after an ischaemic process, in a way to quantify the restoration of myocardial behavior after the supply of oxygen to the ventricular wall was suppressed for a brief period.

A Novel Interpretation for Arterial Pulse Pressure Amplification in Health and Disease.

Arterial pressure waves have been described in one dimension using several approaches, such as lumped (Windkessel) or distributed (using Navier-Stokes equations) models. An alternative approach consists of modeling blood pressure waves using a Korteweg-de Vries (KdV) equation and representing pressure waves as combinations of solitons. This model captures many key features of wave propagation in the systemic network and, in particular, pulse pressure amplification (PPA), which is a mechanical biomarker of cardiovascular risk. The main objective of this work is to compare the propagation dynamics described by a KdV equation in a human-like arterial tree using acquired pressure waves. Furthermore, we analyzed the ability of our model to reproduce induced elastic changes in PPA due to different pathological conditions. To this end, numerical simulations were performed using acquired central pressure signals from different subject groups (young, adults, and hypertensive) as input and then comparing the output of the model with measured radial artery pressure waveforms. Pathological conditions were modeled as changes in arterial elasticity (E). Numerical results showed that the model was able to propagate acquired pressure waveforms and to reproduce PPA variations as a consequence of elastic changes. Calculated elasticity for each group was in accordance with the existing literature.

Conceptual model of arterial tree based on solitons by compartments.

Models define a simplification of reality, which help to understand function. The arterial system has been modeled in many ways: lumped models, tube models and anatomically based distributed models. In this work, arterial segments were modeled as thin nonlinear elastic tubes filled with an incompressible fluid, whose governing dynamics were denoted by the Korteweg and DeVries equation. In order characterize the pressure pulse propagation, a discrete multi-segmented conduit was proposed. Arterial wall mechanical parameters were obtained from existing literature and assigned to each individual segment. The numerical model was developed starting in the aortic arch, and ending at the femoral artery. The main idea of this article was to perform a computational simulation of pressure wave propagation, considered as a solitons combination, along several segments of the arterial tree.

Arterial pressure fractality is highly dependent on wave reflection.

UNLABELLED: Wave reflection is an important factor that influences pressure wave morphology and becomes more significant with aging, when cardiovascular risk increases. A pressure wave, measured at any location in the arterial tree, can be decomposed into its forward and backward components and depends on the corresponding amplitude and shifting time delays. Fractal dimension (FD) quantifies the time series complexity defined by its geometrical representation. OBJECTIVE: The aim of this study was to evaluate the arterial pressure and diameter time series in order to assess the relationship between wave reflection and arterial pressure fractal dimension (FD). METHODS: Simultaneous aortic pressure and diameter were measured in 14 conscious dogs. A pair of ultrasonic crystals, a pressure microtransducer and a pneumatic cuff occluder were positioned in the upper third of the descending aorta. RESULTS: Total reflection induced by the occlusion maneuver decreased FD concomitant to the aortic stiffening. CONCLUSION: Arterial pressure fractality is highly dependent on wave reflection.

Coronary arterial stiffness is related with a loss of fractal complexity in the aortic pressure.

UNLABELLED: Arterial stiffening is a common but highly variable disorder. Additionally, excessive arterial pulsatility is associated with various common diseases of aging and hypertension. Fractal dimension (FD) quantifies the time series complexity defined by its geometrical representation. OBJECTIVE: Arterial pressure and diameter time series were evaluated in order to assess the relationship between arterial stiffness and FD. METHODS: Three Corriedale male sheep were operated. Left anterior descending artery (LAD) was dissected and the external arterial diameter was measured trough sonomicrometry. Similarly, a pressure microtransducer was positioned in the upper third of the ascending aorta. Simultaneous pressure and diameter were measured in normal state and under smooth muscle activation. Each time series FD were assessed by the application of Higuchi's method while arterial wall elastic modulus was evaluated by means of the pressure-strain relationship. RESULTS: Coronary stiffness was increased from normal state to phenylephrine state (47.32%, 21.12%, 10.87%) while aortic pressure FD was decreased (2.11%, 2.57%, 6.85%), respectively. CONCLUSION: Acute hypertension induced by phenylephrine produces an increase in the coronary wall elastic modulus with a concomitant decrease in the fractal nature of the aortic pressure, suggesting that coronary stiffening is associated with an unwrinkled aortic pressure.

Mistletoe in conventional oncological practice: exemplary cases.

Mistletoe therapy, a cancer treatment suggested by Rudolf Steiner in 1920, is a typical and specific anthroposophic therapy, but could become more important today in the field of mainstream medicine. This article analyzes some of the most typical effects of mistletoe therapy based on the experience of more than 100 cases. A few patients were chosen who appear exemplary of the opportunities offered by mistletoe therapy. Their clinical history demonstrates an improvement in clinical condition and performance status, better quality of life, improved psychological status, reduction of infective events, better tolerance of concomitant chemoradiotherapy, and even a direct reduction of tumor size. The conclusion is that the patients may be indicative for future prospective clinical studies designed to confirm a real efficacy of mistletoe in cancer therapy.