Equilibration Of Water Research Articles

An in situ sampler for close interval pore water studies1

A sampler for defining compositional changes over distances on the order of 1 cm in aqueous systems operates by equilibration of water contained by a dialysis membrane with the surrounding water. Depth profiles of methane and phosphate in Hudson Estuary sediments are presented as examples.

Kinetics of the extracellular space in newborn animals submitted to surgical trauma

The kinetics of the extracellular fluid of newborn piglets submitted to a standard surgical trauma was studied through a compartment analysis of a kinetic model that conformed with the physiology of the EC fluid and of its functional components, the rapidly equilibrating and the slowly equilibrating components. After trauma, there was a decrease in the volume of the rapid-exchange compartment, an increase in the slow-exchange compartment, and alteration in the exchange rate of the slow-exchange compartment. Contrary to that found in the adult organism, there was no delay for isotopic equilibrium. It was also shown that, after trauma, there is a decrease in the initial radiobromide distribution volumes (2, 5 and 10 min) with a tendency to normalization at 20 min, a time very close to that necessary for final equilibration of extracellular water. These findings characterize the dynamics of the extracellular space in the early postoperative phase of newborn organisms and indicate their autoregulatory capacity, probably due to their great functional reserve of water.

Some Aspects of the Physiology of Sheep Foetal Fluids

Mechanisms of amniotic and allantoic fluid formation have been outlined using results from chronically catheterized sheep conceptuses. Important factors are foetal urine composition, urine distribution between the two fluid sacs, and equilibration of solutes and water between the fluids and foetal or maternal blood influenced by membrane permeabilities and membrane transport mechanisms under foetal control. In amniotic fluid, influences of foetal respiratory, nasal and buccal secretions and of foetal swallowing also have an effect. Changes in foetal urine and allantoic fluid compositions seem to be a relatively sensitive index of foetal stress, and of foetal endocrine involvement in glucose homeostasis and the onset of parturition. Examples are given of the use of such changes in monitoring foetal physiology. Although the functions of many changes in foetal fluid composition are unknown, foetal urine influences on amniotic fluid volume may be involved in the initiation of parturition. Les mécanismes de la formation des liquides amniotiques et allantoides ont été décrits à partir des résultats obtenus lors de la cathéterisation chroniques de brebis enceintes. Les principaux facteurs sont la composition de l’urine foetale, la distribution de l’urine entre les liquides et le sang maternel et foetal qui est influencée par les perméabilités de la membrane, les mécanismes de transport de la membrane sous contrôle foetal. Dans le liquide amniotique, les influences de la respiration foetale, les sécrétions nasales et buccales et la déglutation foetale ont aussi des effets. Des changements de composition de l’urine foetale et du liquide allantoique semblent être des indices de la souffrance foetale, et de la participation du système endocrine du foetus lors de l’hémostase glucosique et le début de la partirution. Des exemples sont donnés pour de pareils changements lors du contrôle de la physiologie foetale. Quoique beaucoups de changements de la composition des liquides foetaux n’expliquent pas les fonctions qui se déroulent, les influences de l’urine du foetus sur le volume du liquide amniotique pourraient initier la parturition. Mit Hilfe der durch Langzeitkatheterisierung von Konzeptionsprodukten bei Schafen gewonnenen Resultate wird der Mechanismus der Formation von amniotischer und allantoider Flüssigkeit beschrieben. Wichtige Faktoren waren hierbei die Zusammensetzung des foetalen Urins, die Verteilung des Urins in den Flüssigkeiten sowie foetales und mütterliches Blut beeinflusst durch Permeabilität der Membranen und den unter foetaler Kontrolle stehenden membranösen Transportmechanismus. Bei der amniotischen Flüssigkeit hat ausserdem foetale respiratorische, nasale und buccale Sekretion und das, was der Foetus verschluckert, möglicherweise einen Einfluss. Veränderungen im foetalen Urin und in der Zusammensetzung der allantoiden Flüssigkeit, scheinen einen relativ empfindlichen Index von Foetalem Stress zu sein, sowie von einer Beteiligung der foetalen endokrinen Sekretion bei glucosehomöostasis und dem Beginn des Geburtsvorganges. Beispiele solcher durch Monitor entdeckten Veränderungen in der foetalen Physiologie werden aufgeführt. Obwohl die Funktionen vieler Veränderungen der foetalen Flüssigkeit unbekannt sind, ist es möglich, dass der Einfluss des foetalen Urins auf das amniotische Flüssigkeitsvolumen einen Einfluss auf den Beginn des Geburtsvorganges hat. Se explican en téminos generales los mecanismos de la formación de los flúidos amniótico y alantoides, partiendo de los resultados obtenidos de conceptus ovinos crónicamente cateterizados. Son factores importantes la composición de la orina fetal, la distribución de la orina entre los flúidos y la influencia sobre la sangre fetal o materna de la permeabilidad de las membranas y de los mecanismos de transporte de la membrana que se hallan bajo el control del feto. Las influencias de las secreciones respiratoria, nasal y bucal y de la deglución fetal también afectan al flúido amniótico. Los cambios en las composiciones de la orina fetal y del flúido alantoides parecen ser un índice relativamente sensitivo de las tensiones fetales, y de la función endocrina del feto en la homeostasis de la glucosa y en el comienzo de la parturición. Se dan ejemplos del empleo de tales cambios en la observación de la fisiología fetal. Aunque se desconocen las funciones de muchos cambios en la composición del flúido fetal, las influencias de la orina fetal sobre el volumen del flúido amniótico pudieran estar en juego en la iniciación de la parturición.

The effect of route of dosing and method of estimation of tritiated water space on the determination of total body water and the prediction of body fat in sheep

SUMMARYEight mature female sheep were offered a ration which maintained body weight constant during a 20-week period. During the final 10 weeks a comparison was made in each animal of the pattern of equilibration and urinary losses of tritiated water during 8 h after dosing by four different routes. These were intravenous, intraperitoneal, intraruminal and a combination of the intraperitoneal and intraruminal routes. Tritiated water spaces were calculated from (a) the 8-h plasma specific activity and (b) by extrapolation to zero time of the plasma specific activities during the 7 days after injection. At the end of the experiment the fat and water contents of the bodies of the sheep were determined directly.Complete equilibration of tritiated water between plasma and rumen water was not achieved in all animals 8 h after intravenous or intraperitoneal injection but was when the rumen was primed by the combination of intraperitoneal and intraruminal dosing. After intraruminal dosing equilibration was not achieved in any animal within 8 h of dosing.Urinary losses of marker were lower after intraruminal dosing but otherwise averaged 4–5 % of the dose/1 urine. This was equivalent to 0·3–6·7% of the dose for individual sheep.Errors resulting from incomplete equilibration and urinary loss of marker did not influence the efficiency of prediction of total body water from tritiated water space. The multiple correlation coefficient relating body fat with empty body weight and its water content was very high (r = 0·99). Errors introduced into this relationship by the inclusion of gut water in the prediction equations were apparently of a similar magnitude to those resulting from the errors in the estimation of tritiated water space.The extrapolation method for the determination of tritiated water space was shown to have the same accuracy as equilibration techniques under these controlled dietary conditions.

Lowering of the Saturation Solubility of Oxygen by the Presence of Another Gas

A STUDY by Maharajh and Walkley1 of the apparent reduction of oxygen solubility in the presence of a second gas ignores a considerable body of literature evidence in conflict with their conclusions. Their assertion that few determinations have been made of the solubility of oxygen in the presence of nitrogen is incorrect. Equilibration of water with pure oxygen at various partial pressures has been used in several investigations of saturation solubility2–9. Many other determinations of this quantity have been made by equilibrating the liquid phase with air and subsequently determining the dissolved oxygen by chemical means5,7,10–13. The solubility coefficients for oxygen in distilled water obtained over the past eighty years by these two methods show no significant difference7 (range about 2.5% at 25° C for all studies quoted). Morris, Stumm and Galal5 used both approaches in a single investigation.

Foetal placental blood flow in the lamb.

1. Fifteen sheep foetuses of 1.5-5.2 kg body weight were prepared with indwelling arterial and venous catheters for experimentation one to six days later.2. Unanaesthetized foetuses were found to have mean arterial and central venous blood pressures of 40 +/- 1.5 (S.E. of mean) and 2.0 +/- 0.3 (S.E. of mean) mm Hg respectively, compared to intra-uterine pressure. Intra-uterine pressure was 16 +/- 0.8 (S.E. of mean) mm Hg with respect to atmospheric pressure at mid-uterine level.3. Mean placental blood flow of the foetuses was 199 +/- 20 (S.E. of mean) ml./(min.kg body wt.). Mean cardiac output in eleven of the foetuses was 658 +/- 102 (S.E. of mean) ml./(min.kg).4. Mean foetal and maternal colloid osmotic pressures were 17.5 +/- 0.7 (S.E. of mean) and 20.5 +/- 0.6 (S.E. of mean) mm Hg respectively at 38 degrees C.5. Intravenous infusions into six ewes of 1.8 mole of mannitol and 0.4 mole of NaCl resulted in significant increases in foetal plasma osmolarity, sodium, potassium, and haemoglobin concentrations, without detectable transfer of mannitol to the foetal circulation.6. In the sheep placenta there is osmotic and hydrostatic equilibration of water. As a consequence, there should be an interaction between foetal placental blood flow and foetal water exchange with the maternal circulation. It was concluded that this interaction tends to stabilize foetal placental blood flow.

Chemical characteristics and equilibration in natural water-felsic rock-C0 2 system

Weight proportions of the major dissolved species in water from rocks of the Bohemian massif containing alkali feldspars follow the sequence Na + ≥ HCO 3 − > Cl − > SO 4 2− > K + ≷ H 4SiO 4 . For other localities a common order is Na + ≥ HCO 3 − > Cl −> H 4 SiO 4 ≅ SO 4 2− > K +. Calcium and magnesium ions change their place in the sequence as the total dissolved solids increase. Cold water samples (<18°C) were in contact with a soil atmosphere in which Pco 2 ranges from 10 −2 to 10 −1 atm. Hot water (18°C to 72°C) was in contact with subsurface atmospheres in which Pco 2, varies widely from 10 −5 to 10 1 atm. The high Pco 2 was observed in water from the Bohemian massif where CO 2 of a deep, possibly magmatic, origin occurs. Ground water is usually not in chemical equilibrium with respect to its rock environment but its chemical composition changes towards an equilibrium state. The equilibration of rain water or snow melt with rock probably includes (1) fast adsorption of hydroxyl ions on surfaces of aluminum silicates, (2) incongruent hydrolysis of primary aluminum silicates, (3) diffusion of cations from the inner structures of aluminum silicates into solution in exchange for hydrogen ions and (4) reversible exchange of silica and probably alumina between the solution and amorphous surface layers of aluminum silicates. The activity of H + in ground water is probably a function of the rate of hydrogen diffusion into aluminum silicates and the flux of CO 2. The activity of sodium ion was found to vary with temperature and Pco 2, but residence times of ground waters and the specific surface area of the aquifer can influence the activity significantly. The activity of calcium ions may be controlled by incorporation of calcium ions in the structure of a secondary aluminum silicate such as Ca-montmorillonite. Extremely low activities of calcium ions in some waters from felsic rocks are caused by precipitation of calcium carbonate. Chemical compositions of feldspars having An 0–40 are probably not decisive controlling factors of the calcium concentration in the group of ground-water samples studied.

Estimation of water content by tritium dilution of animals subjected to rapid live-weight changes

SUMMARYThe use of tritiated water to estimate total body-water content of animals experiencing recovery from under-nutrition was studied.The time for equilibration of tritiated water (TOH), given intraperitoneally, with total body water (TBW) was determined in rabbits and in rats. As judged by the specific activity of blood water, equilibration had occurred by 76–125 min in the rabbit and did not appear to be affected by the plane of nutrition. However, between slaughter groups the specific activity of water obtained from the liver 180 min after injection of TOH was significantly different from the specific activity of water simultaneously obtained from the blood plasma. It is concluded that the liver is not a suitable tissue to use for testing achievement of equilibration.As judged by the specific activity of blood water compared to that of water from the whole body macerate, equilibration in mature rats either in stable body condition or undergoing rapid compensatory growth occurred in less than 60 min.A trial comparing TOH-space (corrected by 3% body weight) and actual TBW (by desiccation) was conducted on thirty rabbits which experienced under-nutrition followed by compensatory growth.Prior to under-nutrition the agreement between actual and estimated TBW was satisfactory and within 2·3%. During compensatory growth the agreement was poor— the TOH values over-estimating actual TBW by about 12%.A trial with mature rats confirmed the findings with rabbits. For rats in stable body weight the mean estimated TOH-space for fourteen animals was within 1·2% of the actual TBW. For fourteen rats undergoing compensatory growth the mean estimated TOH-space (corrected by 3% body weight) overestimated actual TBW by 6·2%.

Equilibrium of water between gelatin solution and ice

AbstractThe equilibration of water between aqueous gelatin solution and physically separate cakes of ice was observed. Typically, the water content of the solutions reached a nearly steady value several times before final equilibrium, reasons for which are discussed. The equilibrium gelation concentrations were found to be 72 ± 1%, 77 ± 2%, and 80 ± 3% at −10, −21, and −33°C., respectively, in moderately good agreement with predictions based on the vapor pressure measurements of Bull at higher temperatures.

DIFFUSION OF TRITIATED WATER INTO COLLECTING DUCT URINE IN THE DOG.

When tritiated water is infused during stopped flow in the dog the renal papilla is 8.7% as well labeled as is the cortex, when no urine is permitted to escape. With urine escape, the first urine from the collecting ducts is only 4.5% as well labeled as is the cortex, and the last urine (cumulative volume up to 4.5 ml) is considerably less labeled than are the papillae from which it has just emerged. We thus find that in our present series (kidneys frozen before sectioning), as well as in our earlier series with nonfrozen kidneys, diffusion equilibration of tritiated water between papilla tissue water and collecting duct urine is incomplete in the dog.

Post-operative absorption of water from the small intestine

An investigation of water absorption from the small intestine after abdominal surgery has produced more detailed information on the effect of trauma on the motility of the gastro-intestinal tract. Whereas...

Equilibration of water and sodium in blood and tissues.

Equilibration of water and sodium in blood and tissues.

Water exchange in animal and human tumors

The equilibration of tritiated water in the blood with the water of nine tumors of wide histologic variety and anatomic location in four different host species, rat, mouse, hamster and man, was studied following intravenous injection of labeled water. Evidence is presented that the rate of water exchange for eight of these tumors is essentially the same; that tumor water in comparison with liver, muscle and skin equilibrates slowly with blood water; that the major limiting factor in this exchange is blood supply; and that the rate of water exchange in the tumor is increased by ether anesthesia. Submitted on August 9, 1960

Further studies on the absorption and equilibration of water (deuterium oxide) from the gastro-intestinal tract.

Departments of Surgery, Baylor University College of Medicine, Houston, Texas and Emory University School of Medicine, Atlanta, Georgia. In collaboration with the National Bureau of Standards, Washington, D. C.