Nonlinear indicial response of complex nonstationary oscillations as pulmonary hypertension responding to step hypoxia
نویسندگان
چکیده
منابع مشابه
Nonlinear indicial response of complex nonstationary oscillations as pulmonary hypertension responding to step hypoxia (degree of nonlinearityyFourier spectrumyHilbert spectrumynonlinear relationships)
This paper is devoted to the quantization of the degree of nonlinearity of the relationship between two biological variables when one of the variables is a complex nonstationary oscillatory signal. An example of the situation is the indicial responses of pulmonary blood pressure (P) to step changes of oxygen tension (DpO2) in the breathing gas. For a step change of DpO2 beginning at time t1, th...
متن کاملUse of intrinsic modes in biology: Examples of indicial response of pulmonary blood pressure to 6 step hypoxia (nonstationaryystochastic processyFourier spectrumyHilbert spectrumynonlinear oscillations)
Recently, a new method to analyze biological nonstationary stochastic variables has been presented. The method is especially suitable to analyze the variation of one biological variable with respect to changes of another variable. Here, it is illustrated by the change of the pulmonary blood pressure in response to a step change of oxygen concentration in the gas that an animal breathes. The pre...
متن کاملPulmonary hypertension in high-altitude chronic hypoxia: response to nifedipine.
Permanent residents at high altitude may develop excessive polycythaemia (H-Hb) and pulmonary hypertension, which often leads to cardiac failure. Inhibitors of calcium channels have been shown to reverse pulmonary hypertension in respiratory diseases and in primary pulmonary hypertension, but their efficiency has not been evaluated in high-altitude-induced pulmonary hypertension. Systolic pulmo...
متن کاملHypoxia and Pulmonary Hypertension
Vasoconstriction in response to low oxygen tension (hypoxia) in pulmonary arteries is an important physiological adaptation to reroute blood flow to areas of higher oxygenation for effective gaseous exchange. However, chronic hypoxia is a common feature of lung disease, such as chronic obstructive pulmonary disease (COPD). Hypoxic stress triggers cellular phenotypic alterations including increa...
متن کاملThe role of collagen in extralobar pulmonary artery stiffening in response to hypoxia-induced pulmonary hypertension.
Hypoxic pulmonary hypertension (HPH) causes extralobar pulmonary artery (PA) stiffening, which potentially impairs right ventricular systolic function. Changes in the extracellular matrix proteins collagen and elastin have been suggested to contribute to this arterial stiffening. We hypothesized that vascular collagen accumulation is a major cause of extralobar PA stiffening in HPH and tested o...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Proceedings of the National Academy of Sciences
سال: 1999
ISSN: 0027-8424,1091-6490
DOI: 10.1073/pnas.96.5.1834