scholarly journals Dependency Structures in Differentially Coded Cardiovascular Time Series

2017 ◽  
Vol 2017 ◽  
pp. 1-17 ◽  
Author(s):  
Tatjana Tasic ◽  
Sladjana Jovanovic ◽  
Omer Mohamoud ◽  
Tamara Skoric ◽  
Nina Japundzic-Zigon ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Time Series ◽  
Systolic Blood Pressure ◽  
Dynamic Range ◽  
Time Lag ◽  
Conditional Entropy ◽  
Pulse Interval ◽  
Time Lags ◽  
Aging Rats ◽  
Male Wistar Rats

Objectives. This paper analyses temporal dependency in the time series recorded from aging rats, the healthy ones and those with early developed hypertension. The aim is to explore effects of age and hypertension on mutual sample relationship along the time axis.Methods. A copula method is applied to raw and to differentially coded signals. The latter ones were additionally binary encoded for a joint conditional entropy application. The signals were recorded from freely moving male Wistar rats and from spontaneous hypertensive rats, aged 3 months and 12 months.Results. The highest level of comonotonic behavior of pulse interval with respect to systolic blood pressure is observed at time lagsτ=0, 3, and 4, while a strong counter-monotonic behavior occurs at time lagsτ=1and 2.Conclusion. Dynamic range of aging rats is considerably reduced in hypertensive groups. Conditional entropy of systolic blood pressure signal, compared to unconditional, shows an increased level of discrepancy, except for a time lag 1, where the equality is preserved in spite of the memory of differential coder. The antiparallel streams play an important role at single beat time lag.

Dietary linoleic acid and salt-induced hypertension

1981 ◽  
Vol 59 (8) ◽  
pp. 872-875 ◽  
Author(s):  
Murray C. Macdonald ◽  
Robert L. Kline ◽  
Gordon J. Mogenson
Keyword(s):  
Blood Pressure ◽  
Linoleic Acid ◽  
Systolic Blood Pressure ◽  
Wistar Rats ◽  
Sodium Content ◽  
Significant Elevation ◽  
Dietary Linoleic Acid ◽  
Low Level ◽  
Induced Hypertension ◽  
Male Wistar Rats

Male Wistar rats chronically fed a low level (0.41%) of linoleic acid (LA) in the diet as supplied by 5% olive oil developed a significant elevation of systolic blood pressure as compared with rats fed either a medium (4.2%) or high (9.4%) level of dietary LA. Chronic excess intake of NaCl (3.75% in the diet) was associated with a significant elevation of blood pressure on all three diets but a low level of LA in the diet exaggerated the salt-induced hypertension. The results suggest that inadequate dietary LA may result in an increase in systolic blood pressure regardless of the sodium content of the diet.

scholarly journals Hacia el esclarecimiento del rol del anión cloruro en la hipertensión arterial: su vínculo con el daño oxidativo en el riñón

2021 ◽  
Vol 89 (2) ◽  
pp. 98-106
Author(s):  
Nicolas M. Kouyoumdzian ◽  
Gabriel Kim ◽  
Gabriel D. Robbesaul ◽  
Paula D. Prince ◽  
Ana M. Puyó ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Renal Function ◽  
Systolic Blood Pressure ◽  
Renal Cortex ◽  
Fractional Excretion ◽  
Thiobarbituric Acid ◽  
Standard Diet ◽  
Fractional Excretion Of Sodium ◽  
Male Wistar Rats ◽  
Gpx Activity

Introduction: The role of the chloride anion on the deleterious effects of excessive consumption of salt (NaCl) and whether its effects are independent each other of the presence of sodium remains to date, unknown and unclear. Objective: To demonstrate that both a chloride overload and a sodium overload in the diet produce deleterious effects, by different mechanisms, on systolic blood pressure (SBP), renal function and markers of oxidative stress in the kidney. Materials and Methods: Male Wistar rats were divided into four groups (n = 8 / group) and fed with different diets for three weeks: C: control (standard diet), and diets: NaCl: hypersodic-hyperchloric; Na: hypersodic without chloride and Cl: hyperchloric without sodium. Systolic blood pressure (SBP) and renal function were determined, and the production of thiobarbituric acid reactive species (TBARS) and the activity and expression of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) enzymes were evaluated in renal cortex tissue. Results: SBP increased (*) in the two groups fed with chloride. The fractional excretion of sodium and chloride increased (*) in the NaCl and Na groups. increased (*) in the renal cortex with the three diets. No changes were observed in the activity and expression of SOD and CAT. GPx activity increased (*) in the two groups that received chloride; (* p <0.05 vs C). Conclusion: Both sodium and chloride overload are associated with a higher oxidative state characterized by an increase in lipid peroxidation in the renal cortex. However, compared with Na group, only chloride overload is associated with higher GPx activity and hypertension without any changes in urinary chloride excretion, suggesting a higher renal pro-oxidant state in this experimental group.

ATROPINE REDUCES THE TRANSFER FUNCTION MAGNITUDE OF SYSTOLIC BLOOD PRESSURE (SBP) TO PULSE INTERVAL (PI).

1999 ◽  
Vol 31 (Supplement) ◽  
pp. S197
Author(s):  
K. J. Formes ◽  
D. W. Wray ◽  
R. Welch-O'Connor ◽  
A. H. O-Yurvati ◽  
I. P. Reese ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Transfer Function ◽  
Systolic Blood Pressure ◽  
Pulse Interval

Detrended Correlogram Method for Non-Stationary Time-Series Analysis

2021 ◽  
pp. 2250012
Author(s):  
G. F. Zebende ◽  
E. F. Guedes
Keyword(s):  
Time Series ◽  
Time Series Analysis ◽  
Correlation Coefficient ◽  
Memory Effect ◽  
Cross Correlation ◽  
Time Lag ◽  
Stationary Time Series ◽  
Time Lags ◽  
Statistical Tool ◽  
Auto Correlation

A correlogram is a statistical tool that is used to check time-series memory by computing the auto-correlation coefficient as a function of the time lag. If the time-series has no memory, then the auto-correlation must be close to zero for any time lag, otherwise if there is a memory, then the auto-correlations must be significantly different from zero. Therefore, based on the robust detrended cross-correlation coefficient, [Formula: see text], we propose the detrended correlogram method in this paper, which will be tested for some time-series (simulated and empirical). This new statistical tool is able to visualize a complete map of the auto-correlation for many time lags and time-scales, and can therefore analyze the memory effect for any time-series.

Effects of aging on 24-h dynamic baroreceptor control of heart rate in ambulant subjects

1995 ◽  
Vol 268 (4) ◽  
pp. H1606-H1612 ◽  
Author(s):  
G. Parati ◽  
A. Frattola ◽  
M. Di Rienzo ◽  
P. Castiglioni ◽  
A. Pedotti ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Systolic Blood Pressure ◽  
Baroreflex Sensitivity ◽  
Regression Line ◽  
Domain Analysis ◽  
Pulse Interval ◽  
Alpha Coefficient ◽  
Baroreflex Control ◽  
Effects Of Aging

The effects of aging on the dynamic modulation of baroreflex sensitivity over 24 h was assessed in eight elderly (mean age +/- SD, 63.9 +/- 3.2 yr) and in eight young (23.9 +/- 6.1 yr) mild or moderate essential hypertensive patients, who were subject to a 24-h intra-arterial (Oxford technique) blood pressure recording in ambulatory conditions. The sensitivity of baroreflex control of the heart rate was dynamically assessed by quantifying 1) the slope of the regression line between pulse interval (the reciprocal of heart rate) and systolic blood pressure changes over spontaneously occurring hypertension-bradycardia or hypotension-tachycardia sequences (time domain analysis) and 2) the ratio between spectral-powers of pulse interval and systolic blood pressure around 0.1 Hz (alpha-coefficient: frequency domain analysis). The 24-h average sequence slope was lower in old than in young individuals (4.4 +/- 0.5 vs. 9.9 +/- 1.3 and 4.8 +/- 0.7 vs. 8.4 +/- 1.4 ms/mmHg for hypertension-bradycardia and hypotension-tachycardia sequences, respectively; P < 0.05 for both). Similar results were obtained by using the alpha-coefficient approach. The marked nighttime increase in baroreflex sensitivity observed in young individuals was much less evident in the elderly. Thus 24-h baroreflex sensitivity is markedly impaired by aging. The impairment becomes manifest also as an inability to increase baroreflex sensitivity at night.

Smoking impairs baroreflex sensitivity in humans

1997 ◽  
Vol 273 (3) ◽  
pp. H1555-H1560 ◽  
Author(s):  
G. Mancia ◽  
A. Groppelli ◽  
M. Di Rienzo ◽  
P. Castiglioni ◽  
G. Parati
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Systolic Blood Pressure ◽  
Baroreflex Sensitivity ◽  
Pulse Interval ◽  
Average Systolic Blood Pressure ◽  
Carotid Baroreceptor ◽  
Baroreceptor Stimulation ◽  
Finger Blood Pressure ◽  
Carotid Baroreceptor Stimulation

In 10 healthy smokers, finger blood pressure was recorded continuously for 1 h in a supine control condition and for 1 h while smoking four cigarettes, one every 15 min. Smoking increased average systolic blood pressure (+19%, P < 0.01) and its variability and reduced pulse interval (reciprocal of heart rate, -22%, P < 0.01) and its variability. Baroreflex sensitivity, as assessed by the slope of spontaneous hypertension/bradycardia or hypotension/tachycardia sequences and by the alpha-coefficient (squared ratio between pulse interval and systolic blood pressure spectral powers at 0.1 Hz) was significantly decreased (P < 0.01) during smoking, whereas there were no effects of smoking on the reflex changes in pulse interval induced by carotid baroreceptor stimulation through a neck suction device. Sham smoking by a drinking straw had no effects on any of the above parameters. Thus, when assessed in the absence of laboratory maneuvers in daily life conditions, baroreflex sensitivity is markedly impaired by smoking. This impairment may contribute to the smoking-induced increase in blood pressure and heart rate as well as to the concomitant alterations in their variability.

CHANGES IN SYSTOLIC BLOOD PRESSURE AND PULSE INTERVAL VARIABILITY IN CHILDREN WITH TYPE 1 DIABETES MELLITUS

2011 ◽  
Vol 29 ◽  
pp. e400
Author(s):  
E. Zavodna ◽  
N. Honzikova ◽  
Z. Novakova ◽  
H. Hrstkova ◽  
M. Pejchlova ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Blood Pressure ◽  
Type 1 Diabetes ◽  
Systolic Blood Pressure ◽  
Type 1 Diabetes Mellitus ◽  
Pulse Interval

scholarly journals GRACE-Derived Time Lag of Mekong Estuarine Freshwater Transport in the Western South China Sea Validated by Isotopic Tracer Age

2021 ◽  
Vol 13 (6) ◽  
pp. 1193
Author(s):  
Zhongtian Ma ◽  
Hok Sum Fok ◽  
Linghao Zhou
Keyword(s):  
Time Series ◽  
South China Sea ◽  
South China ◽  
Cross Correlation ◽  
Time Lag ◽  
Time Lags ◽  
Substantial Impact ◽  
China Sea ◽  
Freshwater Transport ◽  
Western South China Sea

Estuarine freshwater transport has a substantial impact on the near-shore ecosystem and coastal ocean environment away from the estuary. This paper introduces two independent methods to track the Mekong freshwater-induced mass transport by calculating the time lag (or equivalently, the phase) between in situ Mekong basin runoff and the equivalent water height (EWH) time series over the western South China Sea from a gravity recovery and climate experiment (GRACE). The first method is the harmonic analysis that determines the phase difference between annual components of the two time series (called the P-method), and the other is the cross-correlation analysis that directly obtains the time lag by shifting the lagged time series forward to attain the highest cross-correlation between the two time series (called the C-method). Using a three-year rolling window, the time lag variations in three versions of GRACE between 2005 and 2012 are computed for demonstrating the consistency of the results. We found that the time lag derived from the P-method is, on average, slightly larger and more variable than that from the C-method. A comparison of our gridded time lag against the age determined via radium isotopes in September, 2007 by Chen et al. (2010) revealed that our gridded time lag results were in good agreement with most isotope-derived ages, with the largest difference less than 6 days. Among the three versions of the GRACE time series, CSR Release 05 performed the best. The lowest standard deviation of time lag was ~1.6 days, calculated by the C-method, whereas the mean difference for all the time lags from the isotope-derived ages is ~1 day by P-method. This study demonstrates the potential of monitoring Mekong estuarine freshwater transport over the western South China Sea by GRACE.

scholarly journals DLBS1033 REDUCES BLOOD PRESSURE OF HYPERTENSIVE WISTAR-STRAIN RATS

2016 ◽  
Vol 51 (3) ◽  
pp. 168
Author(s):  
Suryono Suryono
Keyword(s):  
Blood Pressure ◽  
Systolic Blood Pressure ◽  
Wistar Rats ◽  
Blood Pressure Reduction ◽  
Test Results ◽  
Lower Systolic Blood Pressure ◽  
Treatment Groups ◽  
Wistar Strain ◽  
Male Wistar Rats ◽  
Biomedical Laboratory

The purpose of this study was to determine the effects of DLBS1033 on blood pressure reduction in hypertension--induced wistar strain rats. Design used in this study was true experimental design. The study was conducted at Biomedical Laboratory, Physiology, Faculty of Dentistry, Jember University, and Clinical and Community Pharmacy Laboratory, Pharmacy Faculty, Jember University. Subjects were taken from male Wistar rats aged 2-3 months, weighing 150-200 grams, as many as 22 rats. Intervention samples were induced into hypertension by giving prednisone in a dose of 1.5 mg/kg/day orally and 2% NaCl followed DLBS1033 of 0.5 grams/kgbw/day orally in the treatment group. T test results on systolic blood pressure (p = 0.00), which was <0.05, showing significant differences in systolic blood pressure in treatment groups. It can be concluded that DLBS1033 can lower systolic blood pressure in wistar rats with induced hypertension using prednisone 1.5 mg/kgbw/day and NaCl 2%.

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