The Effect of Posture upon the Composition and Volume of the Blood in Man

Thompson, Willard O.; Thompson, Patricia J.; Dailey, Mary Elizabeth

doi:10.1073/pnas.14.1.94

Cited by 69 publications

(80 citation statements)

References 2 publications

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“…There is a brief and transient phase of plasma volume expansion because of transfer of fluid from the extravascular compartment, but a decrease in plasma volume accounts for about one-third of the early weight loss (84,129,137,(226)(227)(228)332). The fluidrelated weight loss occurs within 3-4 days during bed rest (127,340) (90).…”

Section: Body Compositionmentioning

confidence: 99%

Cardiovascular Adjustments to Gravitational Stress

Blomqvist

Stone

1983

Comprehensive Physiology

198

163

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Section: Body Compositionmentioning

confidence: 99%

Cardiovascular Adjustments to Gravitational Stress

Blomqvist

Stone

1983

Comprehensive Physiology

198

163

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“…In part this is caused by higher peak plasma levels in the upright position. One reason for the difference is a 12-15% reduction in plasma volume on standing (Thompson et al, 1928), the smaller initial volume of distribution in the standing position causing a higher plasma theophylline concentration. This initial difference disappears as the drug diffuses into the extravascular space.…”

Section: Discussionmentioning

confidence: 99%

Posture and theophylline kinetics.

Warren¹,

Cuss²,

Barnes³

1985

Brit J Clinical Pharma

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The effect of posture on theophylline kinetics was examined in six healthy men who took 450 mg slow‐release aminophylline orally at the same time of day on two separate occasions. On one day they remained standing and on the other supine throughout. Plasma theophylline was measured hourly for 6 h from ingestion. Mean theophylline levels were significantly higher in the standing position at all times (P less than 0.01). We conclude that diurnal variation in theophylline kinetics can be explained, at least in part, by differences in posture.

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“…Osmolar and free water clearances were calculated by standard formulae. Changes in plasma volume (PV) were calculated from changes in plasma protein concentration (PP) using the formula PV,/PV, =PP,/PP, x 100 (33).…”

Section: Ria Of a N P And Avpmentioning

confidence: 99%

Effect of Atrial Natriuretic Peptide on the Vasopressin Response to Osmotic and Hemorrhagic Stimuli in Dogs

Inoue

Kimura

Ota

et al. 1990

J Neuroendocrinology

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Effect of atrial natriuretic peptide (ANP) on the vasopressin response to osmotic stimulation (Experiment I) as well as to hemorrhage (Experiment II) was investigated in anesthetized dogs. Moreover, cardiovascular function and renal water and electrolyte excretion were studied. In Experiment I , 2.5 M NaCI, containing 0.02 pg.kg ' of ANP, was infused intravenously at a rate of 0.2 ml.kg-'. min ' after one bolus injection of 0.75 pg.kg ' ANP (HSA group). In the control group, 2.5 M NaCl alone (HS group) was infused.The infusion was continued for 75 min. In Experiment 11, 0.15 M NaCI, containing the identical dose of ANP to Experiment I (HA group), or 0.15 M NaCl alone (H group) was infused intravenously during bleeding at a rate of 1 ml.kg-'.min ' for 40 min. In Experiment I, infused ANP suppressed the vasopressin response to a mild osmotic stimulation, but not to a strong osmotic stimulation and attenuated ANP release and a rise in arterial and central venous pressures in response to plasma volume expansion, without the enhanced natriuresis. In Experiment I I , infused ANP neither impaired t h e vasopressin response to bleeding nor potentiated a fall in mean arterial pressure and central venous pressure.In conclusion, ANP at physiological and/or supraphysiological range may suppress the vasopressin response to a mild osmotic stimulation, but not to a strong osmotic stimulation and to hemorrhage. In addition, ANP given intravenously may attenuate ANP release and a rise in blood pressure without any natriuresis.It has recently been postulated that there is a direct relationship between the release of atrial natriuretic peptide (ANP) and that of vasopressin (AVP), and this mutual relationship may be important in the regulation of body fluid.AVP has been reported to stimulate ANP release in in vivo and in vitw studies (1-3). On the contrary, the central and peripheral administrations of ANP have been shown to attenuate AVP release in euhydration as well as the AVP response to dehydration, hemorrhage and osmotic stimulation in animals (4-9) and human subjects (10. 1 I). Furthermore. ANP was found to attenuate AVP release produced by angiotensin I1 (12). In in vitro studies, moreover, ANP has been reported to stimulate AVP release in small doses, and in large doses, to attenuate the release of AVP (13).On the other hand, it has been documented that peripheral administration of ANP has no effect on AVP release in rats, sheep and man ( 5 , 14-18). Furthermore, AVP release has been shown to increase in response to hypertonic saline given iv. despite a marked rise in ANP release (1 9).Thus, it is still uncertain whether a rise in plasma ANP within physiological and/or supraphysiological range really affects AVP release in response to osmotic and hemorrhagic stimuli.In the present study, therefore, effects of ANP (iv) on AVP release elicited by hypertonic saline and hemorrhagic shock were investigated. Hypertonic saline infusion and continuous bleeding were carried out in ancsthetizcd dogs. In addition. renal water...

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The Effect of Posture upon the Composition and Volume of the Blood in Man

Cited by 69 publications

References 2 publications

Cardiovascular Adjustments to Gravitational Stress

Cardiovascular Adjustments to Gravitational Stress

Posture and theophylline kinetics.

Effect of Atrial Natriuretic Peptide on the Vasopressin Response to Osmotic and Hemorrhagic Stimuli in Dogs

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