There is good correlation between the specific gravity and osmolality of urine obtained from neonates and adults, if specimens contain neither protein nor glucose. The regression equations between specific gravity and osmolality, however, differ considerably between the two age groups, maturation to the adult regression occurring within the first 5 years of life. Specifically derived regression...

PURPOSE This investigation quantified the effect of changes in plasma osmolality on the measurement of hematocrit (Hct) and the implications for the subsequent use of these data to calculate changes in plasma volume and application to the World Anti-Doping Agency Athlete Biological Passport. METHODS Two groups of eight male volunteers visited the laboratory after an overnight fast. In study 1...

Osmotic activity is the process when water in one solution, with lower concentration of e.g. salt ions or sugar molecules, moves through a semipermeable barrier in the direction of a higher concentration to equalize concentrations. The osmotic activity could both be measured in milliosmoles/kilogram (mOsm/kg) solvent, i.e. osmolality, and calculated as milliosmoles/liter (mOsm/L) solution, i.e....

While associations exist between water, hydration, and disease risk, research quantifying the dose-response effect of water on health is limited. Thus, the water intake necessary to maintain optimal hydration from a physiological and health standpoint remains unclear. The aim of this analysis was to derive a 24 h urine osmolality (U(Osm)) threshold that would provide an index of "optimal hydrat...

The relationship between thirst perception and plasma osmolality was studied during hypertonic and physiological saline infusion in ten healthy volunteers. Thirst perception was quantified using a linear visual analogue scale which volunteers marked at intervals during the infusion periods. Infusion of hypertonic saline caused a steady rise in plasma osmolality together with a progressive linea...

GAZITGA, S., J. B. SCOTT, B. SWINDALL, AND F. J. HADDY. Resistance responses to local changes in plasma osmolality in three vascular beds. Am. J. Physiol. 220(Z) : 384-391. 1971 .-The effects of local changes in plasma osmolality (durations of 3-10 min) on resistance to blood flow were compared in the forelimb, renal, and coronary circulations of anesthetized dogs. A 40to 50mOsm/kg increase in ...

When channel catfish (lchtalurus punctatus) in fresh water (FW) were hypophysectomized, plasma osmolality decreased significantly after 24 hrs, and the maximum reduction was seen after 2 days. When they were transferred from FW to dilute seawater (20-40% SW), plasma osmolality of the sham-operated fish was consistently higher than the osmolality of the environmental water, whereas the osmolalit...