Regulation of Water and Some Ions in Gammarids (Amphipoda)

1971 ◽  
Vol 55 (2) ◽  
pp. 325-344
Author(s):  
D. W. SUTCLIFFE

1. Gammarus duebeni from brackish water was acclimatized to salinities ranging from 100% sea water down to 0.25 mM/1 NaCl at 9 °C. 2. The body water content increased from 76 to 81% body wet weight. The ratio of total body sodium/chloride increased from 1.04 to 1.52. The sodium space remained constant, equivalent to about 65 % body H2O. The chloride space decreased from about 60% body H2O down to 35% body H2O. 3. Total body potassium remained almost constant and showed only a small decrease in dilute NaCl-media. Potassium balance was maintained for several days at an external potassium concentration of 0.010-0.015 mM/1. 4. The proportion of body water in the extracellular blood space was calculated from the assumption that potassium and chloride ions were distributed in a Donnan equilibrium between the blood and intracellular spaces. The blood space was slightly smaller than the chloride space. 5. The mean intracellular concentrations of sodium, potassium and chloride were calculated. Sodium fell from 120 to 75 mM/kg cell H2O, potassium fell from 125 to 75 mM/kg cell H2O and chloride fell from 55 to 12 mM/kg cell H2O. These concentrations are similar to the concentrations found in the muscles of decapods and in the tissues of other animals. 6. About 10% of the body chloride and 93-97% of the body potassium is situated in the cells. The proportion of intracellular sodium increased from 17-18% body sodium at 100% sea water to 40-50% body sodium at 0.25 mM/l NaCl. 7. G. duebeni from three freshwater populations were acclimatized to 2 % sea water, 0.5 and 0.25 mM/l NaCl. The body surface is three times more permeable to potassium than it is to sodium and chloride. Potassium balance in starved animals was achieved at 0.010-0.015 mM/l K. Fed animals had a higher body sodium and chloride content than starved animals. 8. The regulation of body water and ions in animals from the freshwater populations was essentially the same as in animals from brackish-water populations. The significance of the results is discussed in relation to the process of adaptation to fresh water.

1971 ◽  
Vol 55 (2) ◽  
pp. 357-369
Author(s):  
D. W. SUTCLIFFE

1. A comparison was made of the body water contents and the concentrations of sodium, potassium and chloride in the blood and body water of Gammarus zaddachi, G. locusta and Marinogammarus finmarchicus. 2. G. zaddachi had a slightly higher body water content than G. locusta and M. finmarchicus. 3. In all three species the blood chloride concentration was lower than the external chloride concentration in 80-113 % sea water, but the blood sodium concentration was equal to or slightly above the sodium concentration in the external medium. 4. The total body sodium concentration was always greater than the total body chloride concentration. In M.finmarchicus the ratio of body sodium/chloride increased from 1.2 to 1.3 over the salinity range 100-20% sea water. In G. zaddachi the ratio of body sodium/chloride increased from 1.08 at 100% sea water to 1.87 in 0.25 mM/l NaCl. 5. The total body potassium concentration remained constant. The potassium loss rate and the balance concentration were relatively high in G. zaddachi. 6. The porportion of body water in the blood space was calculated from the assumption that a Donnan equilibrium exists between chloride and potassium ions in the extracellular blood space and the intracellular space. In G. zaddachi the blood space was equivalent to 60% body H2O at 100% sea water, and equivalent to 50% body H2O at 40% sea water down to 0.5 mM/l NaCl. In M.finmarchicus the blood space was equivalent to 38-44% body H2O at salinities of 20-100% sea water. 7. The mean intracellular concentrations of sodium, potassium and chloride were also calculated. It was concluded that for each ion its intracellular concentration is much the same in the four euryhaline gammarids. The intracellular chloride concentration is roughly proportional to the blood chloride concentration. The intracellular sodium concentration is regulated in the face of large changes in the blood sodium concentration.


1971 ◽  
Vol 55 (2) ◽  
pp. 345-355
Author(s):  
D. W. SUTCLIFFE

1. The water content, and the concentrations of sodium potassium and chloride in the blood and body water were determined in Gammarus pulex acclimatized to external salinities ranging from 0.06 mM/l NaCl up to 50 % sea water. 2. The mean body water content remained constant at 79.0-80.3 % body wet weight. The total body sodium and chloride concentrations were lowered in 0.06 mM/l NaCl and increased markedly at salinities above 10% sea water. The normal ratio of body sodium/chloride was 1.45-1.70, decreasing to 1.0 at 50% sea water. 3. The total body potassium concentration remained constant at 47.5-55.2 mM/kg body H2O. The rate of potassium loss across the body surface was relatively fast. Potassium balance was maintained at an external potassium concentration of 0.005 mM/l by starved animals, and at 0.005 mM/l by fed animals. 4. The proportion of body water in the blood space was calculated from the concentrations of potassium and chloride in the blood and in the body water. The blood space contained 38-42% body H2O in animals from fresh water. The blood space decreased to 31 % body H2O in animals from 0.06 mM/l NaCl. The sodium space was equivalent to about 70 % body H2O. 5. The mean intracellular concentrations of sodium, potassium and chloride were estimated and the results were compared with previous analyses made on the tissues of G. pulex and other crustaceans. It was concluded that in G. pulex from fresh water the distribution of potassium and chloride ions between the extracellular blood space and the intracellular space approximately conforms to a Donnan equilibrium. 30-40% of the body sodium is apparently located in the intracellular space.


1999 ◽  
Vol 45 (7) ◽  
pp. 1077-1081 ◽  
Author(s):  
Graham Jennings ◽  
Leslie Bluck ◽  
Antony Wright ◽  
Marinos Elia

Abstract Background: The conventional method of measuring total body water by the deuterium isotope dilution method uses gas isotope ratio mass spectrometry (IRMS), which is both expensive and time-consuming. We investigated an alternative method, using Fourier transform infrared spectrophotometry (FTIR), which uses less expensive instrumentation and requires little sample preparation. Method: Total body water measurements in human subjects were made by obtaining plasma, saliva, and urine samples before and after oral dosing with 1.5 mol of deuterium oxide. The enrichments of the body fluids were determined from the FTIR spectra in the range 1800–2800 cm−1, using a novel algorithm for estimation of instrumental response, and by IRMS for comparison. Results: The CV (n = 5) for repeat determinations of deuterium oxide in biological fluids and calibrator solutions (400–1000 μmol/mol) was found to be in the range 0.1–0.9%. The use of the novel algorithm instead of the integration routines supplied with the instrument gave at least a threefold increase in precision, and there was no significant difference between the results obtained with FTIR and those obtained with IRMS. Conclusion: This improved infrared method for measuring deuterium enrichment in plasma and saliva requires no sample preparation, is rapid, and has potential value to the clinician.


Author(s):  
G. W. Bryan

The relationship between the ability of brackish water invertebrates to regulate Na and K and the extent to which the radioactive fission product 137Cs can be accumulated has been studied.The brackish water isopod Sphaeroma hookeri and the gastropod Potamopyrgus jenkinsi have been acclimatised to a wide range of sea-water dilutions. Unfed Sphaeroma can survive in sea-water concentrations of 100–2·5%, while Potamopyrgus can live fairly indefinitely in concentrations of 50–0·1%. Measurements of Na and K in the whole animals of both species and in the blood of Sphaeroma have been made. Salt movements are quite rapid and acclimatization to new media is achieved by both species in less than 10 h. Concentration factors for inactive K in particular increase to high values in the more dilute media.Uptake of the isotopes 42K and 137Cs from solution has been examined in both species over a range of sea-water concentrations. All of the body K is exchangeable with 42K and in Sphaeroma exchange of 42K between the blood and tissues is so rapid that the body surface appears to be the limiting factor in the uptake of the isotope. Both species exchange 42K more rapidly in the higher concentrations of sea water and one reason for this may be the existence of an exchange diffusion component of exchange which increases as the salinity of the medium is raised. Indirect evidence suggests that the excretion of 42K in urine is probably not an important factor in exchange.


2021 ◽  
Vol 6 (2) ◽  
Author(s):  
Schotman JM ◽  
◽  
Reichert LJM ◽  
de Boer H ◽  
van Borren MMGJ ◽  
...  

Background: Measurements of Total Body Electrical Resistance (TBER) are used to improve fluid balance management in patients on Hemodialysis (HD). This approach is based on the inverse relation that exists between TBER and body water volumes. Interpretation errors may occur if TBER measurements are affected by factors that are not related to changes in body water. Aim of this paper was to provide an overview of the methodological artifacts commonly encountered in a clinical setting, and to strengthen current evidence of their disturbing effects by performing additional experiments. Methods: This study includes an analysis of available literature data, supplemented with additional experiments in healthy adults and patients. A cutoff of 2.7% was used to classify changes in TBER as significant within individual subjects. Results: Electrode position, electrode interference, differences of measurements performed at the right or left side of the body, presence of orthopedic prosthesis located in the limbs, fluid redistribution induced by longterm changes in body position, and electrolyte abnormalities were the main disturbing factors that can induce a significant change in TBER. Other factors either had no significant disturbing effect or could be easily avoided. Conclusion: TBER measurements require a high degree of standardization to minimize interpretation errors.


1969 ◽  
Vol 50 (2) ◽  
pp. 319-326
Author(s):  
R. R. HARRIS

1. Non-protein and protein nitrogen fractions of the isopod Sphaeroma rugicauda were measured in animals adapted to 100 and 2% sea water. 2. The non-protein nitrogen component was reduced in animals acclimatized to the lower salinity. 3. Free amino acids accounted for 88 and 74% respectively of the non-protein nitrogen in the two salinities. 4. In 2% sea water taurine, proline, glycine, alanine and glutamic acid showed the greatest decreases in concentration compared to the levels measured in animals adapted to 100% sea water. 5. The decrease in total free amino acids of animals acclimatized to 100% sea water and transferred to 2% sea water was measured. 6. The total free amino acid concentration is reduced to the 2% sea water level within 12 hr. after transfer. 7. Free amino acid, haemolymph sodium and total body sodium levels after transfer to 2% sea water were compared. 8. The asymmetry between the fall in haemolymph sodium concentration and the decrease in total body sodium under these conditions is thought to be due to a water shift from the haemolymph into the tissues. 9. It is suggested that the osmotic pressure of the cells falls at a slower rate than that of the haemolymph.


1972 ◽  
Vol 57 (3) ◽  
pp. 821-838
Author(s):  
JOHN P. LEADER

1. The larva of Philanisus plebeius is capable of surviving for at least 10 days in external salt concentrations from 90 mM/l sodium chloride (about 15 % sea water) to 900 mM/l sodium chloride (about 150 % sea water). 2. Over this range the osmotic pressure and the sodium and chloride ion concentrations of the haemolymph are strongly regulated. The osmotic pressure of the midgut fluid and rectal fluid is also strongly regulated. 3. The body surface of the larva is highly permeable to water and sodium ions. 4. In sea water the larva is exposed to a large osmotic flow of water outwards across the body surface. This loss is replaced by drinking the medium. 5. The rectal fluid of larvae in sea water, although hyperosmotic to the haemolymph, is hypo-osmotic to the medium, making it necessary to postulate an extra-renal site of salt excretion. 6. Measurements of electrical potential difference across the body wall of the larva suggest that in sea water this tissue actively transports sodium and chloride ions out of the body.


2020 ◽  
Vol 132 (17-18) ◽  
pp. 535-541
Author(s):  
Gregor S. Reiter ◽  
Markus Boeckle ◽  
Christian Reiter ◽  
Monika H. Seltenhammer

Summary Due to a legislative amendment in Austria to determine breath alcohol (BrAC) instead of blood alcohol (BAC) in connection with traffic offences, many results of blood alcohol calculations were simply converted using distinct conversion factors. In Austria, the transformation of BAC to BrAC was carried out by using a factor of 1:2000, which, however, is commonly known to be too low. Noticing the great demand for a calculation method that is not exclusively based on blood alcohol, a formula for calculating breath alcohol based on blood alcohol was published in 1989, but in which the body surface area (BSA) was considered the most important influencing variable. In order to refine this new method, a liquor intake experiment was conducted combined with measurements of total body water (TBW) as an additional variable, using hand to foot bioelectrical impedance assessment (BIA). The test group comprised 37 men and 40 women to evaluate the accuracy of TBW and BSA as an individual parameter for alcohol concentration. The correlation coefficient of BrAC with TBW was constantly higher than with BSA (maximum = 0.921 at 1 h and 45 min after cessation of alcohol intake). These results are valid for both men and women as well as in a gender independent calculation. Hence, for an accurate back calculation of BrAC adjusted values of eliminations rates had to be found. This study describes mean elimination rates of BrAC for both men (0.065 ± 0.011 mg/L h−1) and women (0.074 ± 0.017 mg/L h−1). As previously shown women displayed a significantly higher elimination rate than men (p = 0.006).


1977 ◽  
Vol 232 (1) ◽  
pp. R54-R59 ◽  
Author(s):  
J. M. Culebras ◽  
F. D. Moore

A theoretical calculation of the total nonaqueous exchangeable hydrogen in protein, carbohydrates, and fat in man has been made. It shows that of the total exchangeable hydrogen in the body 5.22% is located in biochemical components, soluble in body water, containing hydrogen that is exchangeable with the isotope. This value represents a maximum upward distortion of total body water measurements by isotope dilution, due to the maximum possible exchangeability in these molecular conformations. From comparative measurements reported in the literature it is clear that this maximum is not achieved during the short period of time during which tritium-dilution studies are performed. It is the authors' belief that the hard-to-exchange amide hydrogens described by Blout in the protein conformations account for this failure of the isotope to achieve complete exchange in the short time allowed.


1930 ◽  
Vol 51 (6) ◽  
pp. 867-878 ◽  
Author(s):  
T. G. H. Drake ◽  
C. F. McKhann ◽  
J. L. Gamble

The circumstances present in upper intestinal obstruction which may be expected to reduce the water content of the body are fasting with water deprivation and a continued loss of secretions into the stomach. According to the data obtained from the above described experiments with rats, loss of body water during the first third of the survival period following pyloric obstruction is more than half accounted for by fasting with water deprivation. This body water is accompanied by a parallel loss of solids and may be regarded as a waste product of the consumption of body fat, glycogen, and protoplasm. Its loss does not disturb the per cent water content of the body tissues. The water lost into the stomach is responsible for an actual excess of water reduction over consumption of solids. Except in the case of the skin and blood, this excess loss of water is extremely small and produces a reduction of the per cent water content of tissues which is so slight as to permit the surmise that the water loss here derives entirely from the interstitial fluid of the tissues and that no dehydration of tissue cells occurs. The data are, however, not directly informative on this point. The total loss of body water during 12 hours following pyloric obstruction was found to be 12.6 per cent of the water content of a control animal. More than one-quarter (28.3 per cent) of the total body content of chloride ion was found to be lost and was entirely accounted for by the amount of chloride found in the gastric contents. Nearly half of the chloride loss derives from the skin. Data are presented which demonstrate that lower intestinal obstruction causes slight, if any, depletion of the water content of the body.


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