BACKGROUND The autonomic nervous system plays a central role in the functioning of systems critical for the homeostasis maintenance. However, its role in the cardiovascular adaptation to pregnancy-related demands is poorly understood. We explored the maternal cardiovascular systems throughout pregnancy to quantify pregnancy-related autonomic nervous system adaptations. METHODOLOGY Continuous ...

A study of respiratory blood pressure variations in normal subjects suggests that variations in both cardiac output and peripheral resistance are involved, the latter mechanism being essentially similar to that producing the Traube waves in apnea. The interactions of the two mechanisms are compared to the known behavior of coupled electronic oscillators. T HE FLUCTUATION of the arterial pressur...

It is of interest that the history of body-enclosing chambers for the treatment of respiratory diseases goes back to at least 1885, when H. F. Williams, an American physician, aided by an engineer friend, used this principle in administering aerosol therapy to patients with pulmonary infections.’ A year later Williams reported that cyclic changes in pressure around the body could be used to pro...

BACKGROUND The dynamic autonomic processes leading to vasovagal syncope are poorly understood. METHODS AND RESULTS We used complex demodulation to continuously assess changes in respiration, R-R interval, and arterial pressure (blood pressure) variability during 60 degree head-up tilt in 25 healthy subjects with tilt-induced vasovagal syncope and 25 age-matched nonsyncopal control subjects. C...

Spectral analysis of skin blood flow has demonstrated low-frequency (LF, 0.03-0.15 Hz) and high-frequency (HF, 0.15-0.40 Hz) oscillations, similar to oscillations in R-R interval, systolic pressure, and muscle sympathetic nerve activity (MSNA). It is not known whether the oscillatory profile of skin blood flow is secondary to oscillations in arterial pressure or to oscillations in skin sympathe...

1. A method is described for measuring tissue oxidation under reduced barometric pressure. 2. The oxygen uptake of yeast is diminished by low barometric pressures to a greater extent than by a reduction of the partial pressure of oxygen, to a corresponding degree, at atmospheric pressure. 3. This effect of low pressure is not observed with certain in vitro oxidation systems. 4. The anaerobic re...

We determined the short-term direct and long-term indirect effects of CO(2) on apparent dark respiration (CO(2) efflux in the dark) in ponderosa pine (Pinus ponderosa Dougl. ex Laws.) seedlings grown in 35 or 70 Pa CO(2) partial pressure for 163 days in naturally lit, controlled-environment chambers. Two soil N treatments (7 and 107 ppm total N, low-N and high-N treatments, respectively) were i...

results the mean age in breathing technique with lavender and breathing technique alone were 25.5 ± 4.3 and 26 ± 4.9, respectively .two groups were comparable in this regards (p = 0.6), but the length of active phase in interventional group was 7.85 ± 3.85 hours and in the control group it was 9.88 ± 6.65 hours. the decrease of the length of labor in the active phase was higher in the experimen...