Plasma volume, fluid shifts, and renal responses in humans during 12 h of head-out water immersion

1992 ◽  
Vol 73 (2) ◽  
pp. 539-544 ◽  
Author(s):  
L. B. Johansen ◽  
N. Foldager ◽  
C. Stadeager ◽  
M. S. Kristensen ◽  
P. Bie ◽  
...  
Keyword(s):  
Plasma Protein ◽  
Plasma Volume ◽  
Evans Blue ◽  
Body Fluid ◽  
Water Immersion ◽  
Time Control ◽  
Fluid Shifts ◽  
And Control ◽  
Renal Responses ◽  
Measurable Change

Changes in plasma volume (PV) throughout 12 h of thermoneutral (34.5 degrees C) water immersion (WI) were evaluated in eight subjects by an improved Evans blue (EB) technique and by measurements of hematocrit (Hct), hemoglobin (Hb), and plasma protein concentrations (Pprot). Appropriate time control studies (n = 6) showed no measurable change in PV. At 30 min of immersion, EB measurements demonstrated an increase in PV of 16 +/- 2% (457 +/- 70 ml). Calculations, however, based on concomitant changes in Hct, Hb, and Pprot showed an increase in PV of only 6.9 +/- 0.9 to 10.0 +/- 0.8% at 30 min of WI. PV values based on EB measurements subsequently declined throughout WI to (but not below) the preimmersion level. Concomitantly, changes in PV calculated from Pprot values remained increased, whereas estimations of changes in PV based on Hct and Hb values returned to prestudy levels after 4 h of immersion. It is concluded that PV initially increases by 16 +/- 2% during WI and does not decline below preimmersion and control levels during 12 h of immersion despite a loss of 0.9 +/- 0.2 liter of body fluid. Furthermore, changes in Hct, Hb, and Pprot do not provide accurate measures of the changes in PV during WI in humans.

Relationship between atrial natriuretic peptide and plasma volume during graded exercise with water immersion

1995 ◽  
Vol 78 (1) ◽  
pp. 217-224 ◽  
Author(s):  
K. Nagashima ◽  
H. Nose ◽  
T. Yoshida ◽  
T. Kawabata ◽  
Y. Oda ◽  
...  
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Plasma Volume ◽  
Water Immersion ◽  
Peak Oxygen Consumption ◽  
Time Control ◽  
Peak Vo2 ◽  
The Difference ◽  
The Relationship ◽  
Atrial Natriuretic

To assess the relationship between atrial natriuretic peptide (ANP) and the reduction in plasma volume (PV) during exercise, we measured changes in PV and ANP in seven male volunteers during treadmill exercise in air (AE) and with water immersion (WE) together with time control studies of rest in air and in water. Blood samples were collected from a catheter in the antecubital vein at exercise intensities of 32, 49, 65, and 78% of peak oxygen consumption (VO2). Plasma ANP in AE increased significantly from the resting value [15 +/- 1 (SE) pg/ml] only at 78% of peak VO2 (29 +/- 5 pg/ml), whereas ANP in WE increased significantly at exercise levels of > 49% of peak VO2 and reached 68 +/- 9 pg/ml at 78% of peak VO2. Although PV in AE and WE decreased significantly with VO2 of > 49% of peak VO2 (P < 0.01), the decrease from the resting value in WE was significantly greater than that in AE of > 65% of peak VO2 (P < 0.01) and the decreases at 78% of peak VO2 were -9.7 +/- 0.8 and -6.1 +/- 1.7%, respectively. The difference in the decrease in PV between AE and WE at corresponding VO2 correlated strongly with that in the increase in ANP (r = -0.97; P < 0.01). These results are consistent with the hypothesis that ANP may be involved in the fluid shift from the intra- to extravascular space during exercise.

Fluid regulatory hormone response to exercise after coca-induced body fluid shifts

1997 ◽  
Vol 83 (2) ◽  
pp. 376-382 ◽  
Author(s):  
R. Favier ◽  
E. Caceres ◽  
B. Sempore ◽  
J. M. Cottet-Emard ◽  
G. Gauquelin ◽  
...  
Keyword(s):  
Plasma Volume ◽  
Arginine Vasopressin ◽  
Body Fluid ◽  
Plasma Catecholamines ◽  
Hemoglobin Concentration ◽  
The Body ◽  
Hormone Response ◽  
Arterial Blood ◽  
Fluid Shifts ◽  
Response To Exercise

Favier, R., E. Caceres, B. Sempore, J. M. Cottet-Emard, G. Gauquelin, C. Gharib, and H. Spielvogel. Fluid regulatory hormone response to exercise after coca-induced body fluid shifts. J. Appl. Physiol. 83(2): 376–382, 1997.—To determine the effect of coca chewing on heart rate (HR), mean arterial blood pressure (MAP), and plasma volume and their relationship with the hormones regulating cardiovascular and body fluid homeostasis, 16 male volunteers were examined at rest and during 1 h of cycle exercise at ∼75% of their peak oxygen uptake in two trials separated by 1 mo. One trial was performed after the subjects chewed a sugar-free chewing gum (Coca− trial), whereas the other was done after the subjects chewed 15 g of coca leaves (Coca+), with the order of the Coca− and Coca+ trials being randomized. Blood samples were taken at rest, before (R1) and after 1-h chewing (R2), and during the 5th, 15th, 30th, and 60th min of exercise. They were analyzed for hematocrit, hemoglobin concentration, red blood cell count, plasma proteins, and for the fluid regulatory hormones, including plasma catecholamines [norepinephrine (NE) and epinephrine], renin, arginine vasopressin, and the atrial natriuretic peptide (ANP). During the control trial (Coca−), from R1 to R2, there was no significant change in hematologic, hormonal, and cardiovascular status except for a small increase in plasma NE. In contrast, it can be calculated that coca chewing at rest induced a significant hemoconcentration (−3.8 ± 1.3% in blood and −7.0 ± 0.7% in plasma volume), increased NE and MAP, and reduced plasma ANP. Chewing coca before exercise reduced the body fluid shifts but enhanced HR response during exercise. These effects were not accompanied by changes in NE, epinephrine, renin, and arginine vasopressin plasma levels. In contrast, plasma ANP response to exercise was lower during the Coca+ trial, suggesting that central cardiac filling was reduced by coca use. It is likely that the reduction in body fluid volumes is a major contributing factor to the higher HR at any given time of exercise after coca chewing.

Role of hemodilution on renal responses to water immersion in humans

1995 ◽  
Vol 269 (5) ◽  
pp. R1068-R1076 ◽  
Author(s):  
L. B. Johansen ◽  
P. Bie ◽  
J. Warberg ◽  
N. J. Christensen ◽  
P. Norsk
Keyword(s):  
Lower Extremity ◽  
Sodium Excretion ◽  
Water Immersion ◽  
Venous Pressure ◽  
Colloid Osmotic Pressure ◽  
Central Venous ◽  
Fluid Shifts ◽  
Capillary Bed ◽  
Renal Responses

The present experiments were designed to elucidate 1) the role of the lower extremity capillary bed in decreasing plasma colloid osmotic pressure (COP) during immersion of humans (n = 8) for 6 h, and 2) the extent to which the natriuresis of water immersion is triggered by this decrease in COP. Irrespective of the depth, COPs were very similar during the immersion procedures, varying between 25.3 +/- 0.5 and 26.4 +/- 0.6 mmHg, which was significantly lower than during control (28.3 +/- 0.3 and 28.6 +/- 0.3 mmHg). During neck immersion, central venous pressure rose instantly by approximately 12 mmHg (P < 0.05) and remained elevated. Only a transient, marginal increase (1.6 +/- 0.7 mmHg) occurred during hip immersion. Cumulated sodium excretion during seated control, hip immersion, and neck immersion, respectively, differed significantly (30 +/- 5, 45 +/- 5, and 101 +/- 6 mmol). It is concluded that the decrease in COP during immersion is primarily due to fluid shifts occurring in the capillary bed of the legs and that this may account for up to 25% of the immersion-induced increase in renal sodium excretion.

Integrative Modeling Platform for Design and Control of an Adaptive Wind Turbine Blade

2018 ◽  
Author(s):  
Hamid Khakpour Nejadkhaki ◽  
John F. Hall ◽  
Minghui Zheng ◽  
Teng Wu
Keyword(s):  
Simulation Model ◽  
Wind Turbine ◽  
Real Time ◽  
Turbine Blade ◽  
Design Tool ◽  
Real Time Control ◽  
Time Control ◽  
Partial Load ◽  
And Control

A platform for the engineering design, performance, and control of an adaptive wind turbine blade is presented. This environment includes a simulation model, integrative design tool, and control framework. The authors are currently developing a novel blade with an adaptive twist angle distribution (TAD). The TAD influences the aerodynamic loads and thus, system dynamics. The modeling platform facilitates the use of an integrative design tool that establishes the TAD in relation to wind speed. The outcome of this design enables the transformation of the TAD during operation. Still, a robust control method is required to realize the benefits of the adaptive TAD. Moreover, simulation of the TAD is computationally expensive. It also requires a unique approach for both partial and full-load operation. A framework is currently being developed to relate the TAD to the wind turbine and its components. Understanding the relationship between the TAD and the dynamic system is crucial in the establishment of real-time control. This capability is necessary to improve wind capture and reduce system loads. In the current state of development, the platform is capable of maximizing wind capture during partial-load operation. However, the control tasks related to Region 3 and load mitigation are more complex. Our framework will require high-fidelity modeling and reduced-order models that support real-time control. The paper outlines the components of this framework that is being developed. The proposed platform will facilitate expansion and the use of these required modeling techniques. A case study of a 20 kW system is presented based upon the partial-load operation. The study demonstrates how the platform is used to design and control the blade. A low-dimensional aerodynamic model characterizes the blade performance. This interacts with the simulation model to predict the power production. The design tool establishes actuator locations and stiffness properties required for the blade shape to achieve a range of TAD configurations. A supervisory control model is implemented and used to demonstrate how the simulation model blade performs in the case study.

Role of endothelium-derived relaxing factors in the renal response to vasoactive agents in hypothyroid rats

2003 ◽  
Vol 285 (1) ◽  
pp. E182-E188 ◽  
Author(s):  
Juan Manuel Moreno ◽  
Rosemary Wangensteen ◽  
Juan Sainz ◽  
Isabel Rodríguez-Gomez ◽  
Virginia Chamorro ◽  
...  
Keyword(s):  
Vascular Reactivity ◽  
Ang Ii ◽  
Vasoactive Agents ◽  
Normal Response ◽  
No Donor ◽  
Increased Sensitivity ◽  
Renal Vascular ◽  
And Control ◽  
Renal Responses

This study analyzed the role of nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF) in the abnormal renal vascular reactivity of hypothyroid rats. Renal responses to vasoconstrictors [VC: phenylephrine (PHE) and ANG II] and vasodilators [VD: ACh, sodium nitroprusside (SNP), and papaverine (PV)] were studied in kidneys from control and hypothyroid rats under normal conditions and after NO or EDHF blockade. NO was blocked by the administration of Nω-nitro-l-arginine methyl ester (l-NAME) and EDHF by the administration of tetraethylammonium (TEA) or by an increased extracellular K+. The response to VC was also evaluated after endothelium removal. Hypothyroid kidneys showed reduced responsiveness to PHE and a normal response to ANG II. l-NAME and TEA administration produced an increased sensitivity to PHE and to ANG II in control preparations. l-NAME also increased the response to PHE in hypothyroid kidneys, but the differences between control and hypothyroid kidneys were maintained. TEA administration did not change the response to either VC in hypothyroid preparations. In endothelium-removed preparations, TEA was unable to increase pressor responsiveness to VC. Hypothyroid kidneys showed reduced responsiveness to ACh and SNP and normal response to PV. The differences between hypothyroid and control preparations in the responses to ACh and SNP were maintained after l-NAME or increased K+. In conclusion, this study shows that 1) the attenuated response to PHE in hypothyroidism is not related to an increased production of endothelium-derived relaxing factors NO and EDHF; 2) the response to VC in hypothyroid preparations is insensitive to EDHF blockade; and 3) hypothyroid preparations have a reduced reactivity to the NO donor, and NO-independent vasodilatation remains unaffected.

scholarly journals CHANGES IN THE VOLUME OF PLASMA AND ABSOLUTE AMOUNT OF PLASMA PROTEINS IN NEPHRITIS

1924 ◽  
Vol 39 (6) ◽  
pp. 921-929 ◽  
Author(s):  
G. C. Linder ◽  
C. Lundsgaard ◽  
D. D. Van Slyke ◽  
E. Stillman
Keyword(s):  
Plasma Protein ◽  
Plasma Volume ◽  
Plasma Proteins ◽  
Protein Concentration ◽  
The Body ◽  
Absolute Amount ◽  
Low Protein

1. We have not observed gross increases in plasma volume in glomerulonephritis, nephrosis, or nephrosclerosis, even when the concentration of plasma proteins was much below normal. Our results indicate the probability that "hydremic plethora" does not occur. 2. The low protein concentration frequently observed in the plasma in nephritis is not due to increased plasma volume but to a decrease of the total amount of plasma protein in the body. 3. Changes in plasma volume showed no constant relationship to changes in edema.

scholarly journals Inflammatory and oxidative alterations of water immersion and epidural analgesia during the labor

2020 ◽  
Vol 7 (8) ◽  
pp. 598-602
Author(s):  
Ümit Yasemin Sert ◽  
Özlem Uzunlar ◽  
Nezaket Kadıoğlu ◽  
Tuba Candar ◽  
Yaprak Engin Üstün
Keyword(s):  
Epidural Analgesia ◽  
Water Immersion ◽  
Demographic Data ◽  
Total Serum ◽  
Control Group ◽  
Epidural Group ◽  
Birth Process ◽  
Apgar Scores ◽  
Significant Difference ◽  
And Control

Objective: Water immersion and epidural analgesia are both pain relief methods used to perceive less pain during the labor process. There are concerns about the maternal and fetal outcomes, although studies presented no significant complication directly related to these methods. We aimed to compare the IL-1 and 6 levels, Total serum oxidant (TOS), antioxidant (TAS) and catalase levels of births with epidural analgesia, water immersion and conventional birth without analgesia. Material and Methods: A total of 88 patients were included in the study (The water immersion group included 29 patients, while the epidural analgesia and control group included 30 and 29 patients respectively). Umblical cord IL-1, IL-6, catalase, TAS, TOS levels, neonatal Apgar scores, duration of birth process and demographic data were compared between three groups Results: There was no significant difference between the three groups in terms of age, Body mass index (BMI), gravidity, parity, gestational week, and birth weight (p>0.05). TOS and IL-6 levels were significantly lower in epidural group than others (p=0.031, p=0.019 respectively). Apgar scores were significantly lower in epidural group (p<0.001). Conclusion: The water immersion and epidural analgesia were found to have no adverse effect on oxidative status and infection parameters of women.

The role of ANP in the reduction of plasma volume during graded exercise with water immersion

1994 ◽  
Vol 1 ◽  
pp. 469
Author(s):  
K. Nagashima ◽  
H. Nose ◽  
T. Yoshida ◽  
T. Kawabata ◽  
T. Morimoto
Keyword(s):  
Plasma Volume ◽  
Water Immersion ◽  
Graded Exercise

Design and Development of a Multi-Module Deployable Manipulator

1999 ◽  
Author(s):  
Kenneth Wong ◽  
Vinod J. Modi ◽  
Clarence W. de Silva ◽  
Arun K. Misra
Keyword(s):  
Real Time ◽  
Experimental Investigations ◽  
Computationally Efficient ◽  
Real Time Control ◽  
Design And Development ◽  
Time Control ◽  
Dynamics And Control ◽  
Manipulator Design ◽  
A Chain ◽  
And Control

Abstract This paper presents the design and development of a Multi-module Deployable Manipulator System (MDMS) as well as a dynamical formulation for it. The system is designed for experimental investigations aimed at dynamics and control of this variable geometry manipulator by implementing different control algorithms to regulate its performance. The manipulator operates in a horizontal plane and is unique in that it comprises of four modules, each of which has one revolute joint and one prismatic joint, connected in a chain topology. Each module has a slewing link of approximately 20cm length and is capable of extending by 15cm. The manipulator design involves the selection and sizing of actuators, the design of mounting and connecting components, and the selection of hardware as well as software for real-time control. The dynamical model is formulated using an O(N) algorithm, based on the Lagrangian approach and velocity transformations. The O(N) character is computationally efficient permitting real-time control of the system.

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