Water Exchange Across Fish Gills: The Significance of Tritiated-Water Flux Measurements

1979 ◽  
Vol 79 (1) ◽  
pp. 147-162 ◽  
Author(s):  
CHRISTOPHER A. LORETZ
Keyword(s):  
Tritiated Water ◽  
Water Flux ◽  
Membrane Resistance ◽  
Temperature Acclimation ◽  
Small Fish ◽  
Turnover Rates ◽  
Major Barrier ◽  
Flow Parameters ◽  
Membrane Permeabilities ◽  
Branchial Membrane

1. Branchial turnover rates of tritiated water in the cyprinid teleost Carassius auratus are temperature dependent and show temperature acclimation with time. 2. Hypoxia produced abrupt increases in the rates of branchial water turnover. 3. The evidence suggests the importance of branchial blood flow parameters and ventilation on turnover rate. Membrane resistance is not a major barrier to water diffusion in these small fish. 4. Calculated apparent diffusional water permeabilities do not represent true branchial membrane permeabilities. Note: Address for correspondence after 1 September 1978: Department of Zoology, University of California, Berkeley, California 94720, U.S.A.

Aspects of the Water, Electrolyte and Carbohydrate Physiology of the Silvereye, Zosterops Lateralis (Aves).

1983 ◽  
Vol 31 (5) ◽  
pp. 695 ◽  
Author(s):  
IJ Rooke ◽  
SD Bradshaw ◽  
RA Langworthy
Keyword(s):  
Natural Habitat ◽  
Tritiated Water ◽  
Free Water ◽  
Laboratory Studies ◽  
Turnover Rates ◽  
Natural Habitats ◽  
Water Influx ◽  
Zosterops Lateralis ◽  
Total Body ◽  
Free Ranging

Total body water content (TBW) and TBW turnover were measured by means of tritiated water (HTO) in free-ranging populations of silvereyes, Zosterops lateralis, near Margaret River, W.A. Birds were studied in their natural habitats during spring and summer, and compared with a vineyard population in summer. In the natural habitat TBW content was found to be 77.6% in spring, which was not significantly different from that measured in summer (78.3%). Birds in vineyards in summer, however, were dehydrated, with a TBW content of 69.4%. Calculated rates of water influx for spring, summer and summer vineyards birds were 1.44,2.20 and 0.65 ml g.day-' respectively. These water turnover rates are much higher than those of any other bird yet studied. Dehydration was marked in the vineyard birds, with a significantly lower TBW content and an average net water loss of 0.63 ml day-'. Laboratory studies showed that silvereyes have a low tolerance to sodium loading. Their tolerance is, however, quite adequate for them to drink the most concentrated free water available to them in the field. Ingestion of concentrated sugar solutions of up to 25% did not provoke an osmotic diuresis and thus cannot account for the dehydration and negative water balance of vineyard birds.

Determining energy expenditure in preterm infants: comparison of 2H(2)18O method and indirect calorimetry

1992 ◽  
Vol 263 (3) ◽  
pp. R685-R692 ◽  
Author(s):  
C. L. Jensen ◽  
N. F. Butte ◽  
W. W. Wong ◽  
J. K. Moon
Keyword(s):  
Heart Rate ◽  
Energy Expenditure ◽  
Preterm Infants ◽  
Indirect Calorimetry ◽  
Water Flux ◽  
High Ratio ◽  
Individual Variability ◽  
Study Time ◽  
Co2 Production ◽  
Turnover Rates

The doubly labeled water (2H(2)18O) method used to estimate total energy expenditure (EETotal) is particularly sensitive to analytic error in preterm infants, because of their high percentage of body water and the high ratio of water flux to CO2 production. To evaluate further use of this method, the EE of 12 preterm infants was measured by indirect calorimetry and 2H(2)18O simultaneously and continuously for 5 days. Initial infant weight, age, and postconceptional age were (means +/- SD) 1,674 +/- 173 g, 4.4 +/- 2.6 wk, and 34.6 +/- 1.6 wk, respectively. The indirect calorimeter system included an air-temperature-controlled chamber and heart rate monitor. EE was measured by indirect calorimetry for 85.6 +/- 4.7% of study time and estimated from the linear regression of heart rate on EE for 14.4 +/- 4.7% of study time. The 2H(2)18O method entailed an initial dose of 100 mg 2H2O and 250 mg 18O/kg and a final dose of 75 mg 18O/kg; urine was collected twice daily. 2H and 18O enrichments were measured by gas-isotope-ratio mass spectrometry. EE was calculated from measured 2H and 18O dilution spaces (NH, NO), turnover rates (kH, kO), and measured respiratory quotient. The ratio of 2H to 18O dilution spaces was 1.01 +/- 0.01 and the ratio of kO to kH was 1.16 +/- 0.04. Estimation of EE from 2H(2)18O and indirect calorimetry agreed within 1%, although individual variability in methods was large.

Accuracy of the tritium water dilution method for determining water flux in reindeer (Rangifer tarandus)

1976 ◽  
Vol 54 (6) ◽  
pp. 857-862 ◽  
Author(s):  
R. D. Cameron ◽  
R. G. White ◽  
J. R. Luick
Keyword(s):  
Total Body Water ◽  
Crude Protein ◽  
Tritiated Water ◽  
Water Flux ◽  
Body Water ◽  
Water Volume ◽  
Dilution Method ◽  
Wide Range ◽  
Total Body ◽  
Water Dilution

The accuracy of the tritium water dilution method in estimating water flux was evaluated in reindeer under various conditions of temperature and diet. Two non-pregnant female reindeer were restrained in metabolism stalls, within controlled-environment chambers, at temperatures of + 10, −5, and −20 °C; varying amounts of a commercial pelleted ration (crude protein, 13%) or mixed lichens (crude protein, 3%) were offered, and water was provided ad libitum either as snow or in liquid form. Total body water volume and water turnover were estimated using tritiated water, and the daily outputs of feces and urine were measured for each of 12 different combinations of diet and temperature. Statistical analysis of the data showed that the tritium water dilution technique gives accurate determinations of total body water flux over a wide range of environmental and nutritional conditions.

scholarly journals WATER TRANSPORT IN INVERTEBRATE PERIPHERAL NERVE FIBERS

1958 ◽  
Vol 41 (5) ◽  
pp. 927-958 ◽  
Author(s):  
Arnold H. Nevis
Keyword(s):  
Peripheral Nerve ◽  
Arrhenius Equation ◽  
Tritiated Water ◽  
Water Flux ◽  
Nerve Fibers ◽  
Nerve Membrane ◽  
Appreciable Change ◽  
A Value ◽  
Apparent Activation Energies ◽  
And Diffusion

Osmotic and diffusion permeabilities (Pf and Pd) of invertebrate nerve fibers to tritiated water were measured to determine what water flux studies could reveal about "the nerve membrane" and to directly test the possibility of active transport of water into or out of invertebrate nerve fibers. Pf/Pd ratios for lobster walking leg nerve fibers were found to be about 20 ± 7 at 14°C. Pd measurements were made for squid giant axons at 25°C. and found to yield a value of 4 x 10–4 cm.–1 sec.–1. When combined with the data of D. K. Hill for Pf, a Pf/Pd ratio of 21 ± 5 is obtained. These Pf/Pd ratios correspond to "effective pore radii" of about 16 ± 4 angstrom units, according to theories developed by Koefoed-Johnsen and Ussing and independently by Pappenheimer and his colleagues. Variations of water flux ratios with temperatures were studied and apparent activation energies calculated for both diffusion experiments and osmotic filtration experiments using the Arrhenius equation, and found to be close to 3 to 5 cal. per mole of water transferred. Cyanide (5 x 10–3 molar) and iodoacetate (1 x 10–3 molar) poisoned lobster leg nerve fibers showed no appreciable change in diffusion or osmotic filtration water effluxes. Caution in interpreting these proposed channels as simple pores was emphasized, but the possibility that such channels exist and are related to ionic flow is not incompatible with electrophysiological data.

Rates of Water Turnover in Marsupials and Eutherians: a Comparative Review With New Data on the Tasmanian Devil.

1978 ◽  
Vol 26 (3) ◽  
pp. 465 ◽  
Author(s):  
SC Nicol
Keyword(s):  
Statistical Analysis ◽  
Turnover Rate ◽  
Tritiated Water ◽  
Tasmanian Devil ◽  
Turnover Rates ◽  
Water Turnover ◽  
Comparative Review ◽  
Lactating Females ◽  
Total Body ◽  
Sarcophilus Harrisii

Water turnover rates of Tasmania devils, Sarcophilus harrisii, were measured under standardized conditions by use of tritiated water. Total body water of lactating females was lower than in non- lactating animals, while water turnover rates per kilogram were not significantly different, due to a higher rate constant for lactating animals. Mean water turnover rates were considerably higher than predicted from other marsupial studies. Statistical analysis of data from 13 species of marsupial and 27 eutherian species showed habitat to have a far greater effect on standard water turnover rate than phylogeny.

scholarly journals Polymer Concentration and Solvent Variation Correlation with the Morphology and Water Filtration Analysis of Polyether Sulfone Microfiltration Membrane

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Muhammad Azeem U. R. Alvi ◽  
Muhammad Waqas Khalid ◽  
Nasir M. Ahmad ◽  
Muhammad Bilal K. Niazi ◽  
Muhammad Nabeel Anwar ◽  
...  
Keyword(s):  
Polymer Concentration ◽  
Water Flux ◽  
Bath Temperature ◽  
Membrane Resistance ◽  
Precipitation Method ◽  
Coagulation Bath ◽  
Membrane Formation ◽  
Polyether Sulfone ◽  
Subsequent Effect ◽  
Coagulation Bath Temperature

Microfiltration flat sheet membranes of polyether sulfone (PES) were fabricated by incorporating varying concentrations of polymer and investigated the influence of substituting solvents. The membranes were prepared via immersion precipitation method. Different solvents that included NMP (N-methyl-2-pyrrolidone), DMF (dimethylformamide), and THF (tetrahydrofuran) were used to analyse their effect on the performance and morphology of the prepared membranes. Two different coagulation bath temperatures were used to investigate the kinetics of membrane formation and subsequent effect on membrane performance. The maximum water flux of 141 ml/cm2.h was observed using 21% of PES concentration in NMP + THF cosolvent system. The highest tensile strength of 29.15 MPa was observed using membrane prepared with 21% PES concentration in NMP as solvent and coagulation bath temperature of 25°C. The highest hydraulic membrane resistance was reported for membrane prepared with 21% PES concentration in NMP as solvent. Moreover, the lowest contact angle of 67° was observed for membrane prepared with 15% of PES concentration in NMP as solvent with coagulation bath temperature of 28°C. Furthermore, the Hansen solubility parameter was used to study the effect on the thermodynamics of membrane formation and found to be in good correlation with experimental observation and approach in the present work.

Water content and water turnover in beef cattle

1968 ◽  
Vol 19 (1) ◽  
pp. 129
Author(s):  
PH Springell
Keyword(s):  
Water Content ◽  
Half Life ◽  
Turnover Rate ◽  
Tritiated Water ◽  
Body Water ◽  
The Body ◽  
Turnover Rates ◽  
Water Turnover ◽  
Poor Diet ◽  
The Mean

Twenty-four steers, comprising British (Hereford and Hereford x Shorthorn), Zebu (Africander), and Zebu cross (British x Brahman or Africander) breeds, were either maintained on pasture, or yarded and fed on diets of a low and a high nutritional value. Tritiated water was injected into the animals on five occasions at intervals of 3 months. The body water content and the water turnover rate were calculated, and some of the sources of variation defined. Observed differences in the water content are attributable to nutritional factors rather than to breed differences. The mean body water content ranged from 615 to 809 ml/kg fasting body weight, where the higher values were associated with a poor diet. The mean half-life of tritiated water was lower in summer (as low as 58 hr) than in winter (up to 128 hr) in grazing and well-fed yarded steers. On a poor diet, however, the half-life in yarded cattle remained high and almost constant throughout the year, dropping to below 100 hr on only a single occasion. Occasionally the half-life was breed dependent, but generally no significant differences between breeds could be found. While mean turnover rates of up to 7.1 ml kg-1 hr-1 were found in better-fed cattle in summer, the value in poorly fed animals was almost constant throughout the year at about 3.3 ml kg-1 hr-1. There was, however, a winter minimum in the well-fed yarded and grazing groups. The turnover rate was also influenced by breed only to a limited extent. The results are interpreted in the light of their possible significance in the adaptation to a tropical environment, and in relation to their value in predicting the body composition.

Measurement of the milk intake of reindeer and caribou calves using tritiated water

1971 ◽  
Vol 49 (4) ◽  
pp. 443-447 ◽  
Author(s):  
E. H. McEwan ◽  
P. E. Whitehead
Keyword(s):  
Tritiated Water ◽  
Caloric Intake ◽  
Milk Intake ◽  
Turnover Rates ◽  
Dilution Technique ◽  
Water Turnover

The relation between water turnover and milk intake of five reindeer and caribou calves was determined using the tritium dilution technique. The results indicate that mean turnover rates of tritiated water of male calves from birth to 4 weeks of age increased from 1.44 to 1.65 liters per day, and that caloric intake ranged from about 3500 to 4100 kcal/day.

Sea Water Drinking and Water Flux in Starved and in Fed Harbor Seals, Phoca vitulina

1971 ◽  
Vol 49 (1) ◽  
pp. 53-62 ◽  
Author(s):  
Florent Depocas ◽  
J. Sanford Hart ◽  
H. Dean Fisher
Keyword(s):  
Food Intake ◽  
Sea Water ◽  
Tritiated Water ◽  
Water Flux ◽  
Harbor Seals ◽  
Total Water ◽  
Total Chloride ◽  
Definitive Evidence ◽  
Water Ingestion ◽  
Terrestrial Mammals

Harbor seals maintained in sea water were either starved or fed graded amounts of herring of known water and total chloride contents. Total body water and exchangeable chloride in the seals were measured by initial dilution of injected tritiated water and Na36Cl. The decline in specific activities of plasma water and chloride was then followed for 12 to 14 days. Average daily fluxes of water and Cl− were calculated. Sea water ingestion was calculated from the daily chloride flux and the chloride contents of the food and sea water. In five animals fed from 0 to 1500 g herring/day, total water flux was linearly related to food intake and ranged from 500 to 1590 ml water per day. In the same animals ingested sea water and metabolic plus inspired water were also linearly related to food intake, and ranged respectively from 35 to 140 ml and 470 to 625 ml water per day. The data provide definitive evidence that starving Harbor seals derive sufficient oxidative water to satisfy the major part of their needs and that they drink very little sea water. In feeding seals the sum of preformed water and metabolic plus inspired water accounts for about 90% of the total water flux, which is comparable in magnitude to that of most terrestrial mammals. The small volume of sea water ingested by Harbor seals, and its linear relationship to food intake, show compellingly that sea water ingestion is coincident to swallowing food under water rather than due to deliberate drinking.

Sign in / Sign up

Export Citation Format

Share Document