Total Body Water Loss Research Articles

Effect of intrauterine growth retardation on postnatal weight change in preterm infants

To investigate the cause or causes of early postnatal weight change, we measured total body water and fluid and energy balances in 14 preterm infants who were appropriate in size for gestational age (AGA) and in 5 weight-matched, preterm, small-for-gestational-age (SGA) infants. On the first day of life, AGA and SGA infants had the same weight and total body water content. At 6 +/- 2 days (mean +/- SD), AGA infants had had significant weight loss (94 +/- 45 gm) and body water loss (67 +/- 80 ml), whereas weight and total body water content in the SGA infants at the same age (5 +/- 1 days) did not differ from the values at birth. Loss of weight and total body water in AGA infants was accompanied by a greater diuresis than in SGA infants at the same amount of fluid intake. At the end of week 1, AGA and SGA infants had the same total energy expenditure (184 +/- 33 vs 171 +/- 17 kJ.kg-1 x day-1); energy intake, which had exceeded total energy expenditure from the third day of life and beyond, already provided 188 +/- 46 (AGA) or 209 +/- 109 kJ.kg-1 x day-1 (SGA), respectively, for energy storage. Nitrogen balance was positive. Subsequent weight gain occurred at the same rate in AGA and SGA infants; both total body water and solids increased. Energy intake, total energy expenditure, and the amount of energy stored (measured during stable weight gain on a regimen of full enteral feedings) had significantly increased compared with week 1, but both groups maintained similar energy storage.(ABSTRACT TRUNCATED AT 250 WORDS)

Body composition and weight maintenance with a very-low-calorie diet for the treatment of moderate obesity

We report body composition in 11 moderately obese patients (mean BMI less than 30) treated for 8 wk with a 2530-kJ/d (605-Kcal) diet. Mean weight loss was 9.4 kg. Fat-free mass (FFM) loss of 2.3 kg was 23% of total weight loss and essentially equal to loss of total body water (2.5 L). Body composition was measured by the Futrex-5000 near-infrared technique. We conclude there is no excess loss of FFM in moderately obese patients treated with MNP 70/70, a 70-g protein, 70-g carbohydrate dietary supplement for 8 wk.

The Use of Tritiated Water to Determine Protein and Lipid Utilization in Fasting Birds: A Validation Study in Incubating Great-Winged Petrels, Pterodroma macroptera

To obtain reference data for the estimation of energy metabolism from body mass (BM) loss in long-term fasting Procellariiformes, we determined the loss of water, lipid, and protein by analysis of body composition in great-winged petrels, Pterodroma macroptera, during the incubation fast. We also examined the validity of the use of total body water (TBW) loss alone to calculate protein and lipid loss. Body composition analysis showed that, during the major part of the 17-d fast, water, lipid, and protein contribute a constant 35.7%, 50.8%, and 13.5%, respectively, of BM loss. The energy content of lipid (adipose triglycerides) was found to be 39. 4 kJ/g. The energy equivalent of BM loss was 22.3 kJ/g; 90% and 10% of energy originated from lipid and protein utilization, respectively. The 376% contribution of water loss to BM loss, estimated from measurement of TBW by using tritiated water, was similar to that obtained by direct analysis of body composition. The loss of protein and lipid was estimated from TBW loss as determined by using tritiated water, with the assumption that water and protein are lost in direct proportion to their content in lipid-free nonbony tissues (LFM). Calculations were based on the finding from analysis of body composition that the percent water content of LFM from which protein is catabolized remains steady during the fast (72.9%). Furthermore, the dry LFM lost is ≥295% protein. This yieldedprotein and lipid losses, and an energy equivalent of BM loss, identical to those obtained by direct analysis of body composition. A good estimate of BM loss composition in long-term fasting petrels may, therefore, be obtained from determination of TBW loss using labeled water. This could be extrapolated to other birds.

The distribution of water in the intracellular and extracellular compartments and the lipid and protein composition of the Mongolian gerbil ( Meriones unguiculatus) during water deprivation

1. 1. The plasma, interstitial, extracellular and intracellular volumes fell to similar extents after 5 days of water deprivation in male and female gerbils. There was no selective plasma volume conservation. 2. 2. The female gerbils lost more weight on water deprivation yet the total body water loss was very similar to that in the male animals. While there was a small fall in the protein content of the male animals the extra loss of weight in the females appeared to be due to the considerable catabolism of lipid stores.

Body water and electrolyte responses to acetazolamide in humans

Acetazolamide (ACZ), a potent carbonic anhydrase inhibitor, is a known diuretic and causal agent in metabolic acidosis. Its diuretic qualities are well established with respect to urine flow and electrolyte excretion. However, the impact of ACZ on body hydration status has not been adequately quantified. Thus, to establish the influence of ACZ treatment on body water, nine healthy males were evaluated for hydration status after clinically prescribed doses of ACZ. The drug was administered in three 250-mg oral doses 14, 8, and 2 h before determination of body water compartments. ACZ led to a significant 1.7-liter reduction in total body water (3.4%). A significant reduction in extracellular water of 3.3 liters is partitioned as the loss of total body water and a significant increase in intracellular water (1.6 liters). Venous blood pH and plasma HCO3- were significantly reduced 0.09 units and 5.9 mM, respectively, with ACZ. Plasma protein concentration was increased, but plasma osmolality did not change. Plasma Na+, K+, and Cl- concentrations were not different with ACZ, but total electrolyte content was significantly decreased 45.2, 1.17, and 44.1 meq, respectively, for all three. Urine K+, HCO3-, flow, and pH were elevated after ACZ treatment, whereas Na+ and Cl- were the same as placebo levels. In conclusion, acute clinical doses of ACZ reduce body fluid compartments, leading to a moderate isosmotic hypovolemia with an intracellular volume expansion as well as metabolic acidosis.

Return to normal body composition after ileoanal J-pouch anastomosis for ulcerative colitis

In 16 patients with ulcerative colitis, total body fat, total body protein, and total body water were measured before and two weeks, three months, and twelve months after the establishment of an ileoanal J-pouch anastomosis. The 16 patients underwent elective surgery for their inflammatory bowel disease but were significantly protein depleted before surgery when their body composition was first measured. Twelve months later, all patients were in good health, back to work, and had normally functioning pouches (average stool frequency 4.3 +/- 1.4 per day). As a group, their stores of body protein and hydration state had returned to normal limits although their body fat stores were increased. Over the postoperative period there were significant losses of weight, protein, fat, fat-free mass, and total body water. These levels had returned to preoperative values (but not to normal) three months later. It is concluded that protein depleted patients with ulcerative colitis presenting for major surgery continue to have distorted body composition for several months after surgery but after approximately 12 months, when they have returned to work and feel well, body composition has returned to normal.

Body Composition, Normal Electrolyte Concentrations, and the Maintenance of Normal Volume, Tonicity, and Acid-Base Metabolism

Because the internal environment of the body is largely a fluid medium, the preservation of the volume and composition of the body fluids is absolutely vital to circulatory status and the extraordinarily complicated functions of the human body. The fluid compartments do not exist as fixed spaces with identical compositions but rather are in constant interchange with each other and have strikingly different compositions. Methods of movement of solutes and water include diffusion along electrochemical gradients, by hydrostatic pressure, osmotic forces, bulk flow, primary and secondary active transport, capillary blood flow, and oncotic pressure. Complex feedback control mechanisms exist to ensure homeostasis or equilibrium and include participation by the kidneys, lungs, gastrointestinal tract, the circulatory system, the endocrine system, and the CNS. The maintenance of extracellular volume is centered around the control of balance of the sodium salts. Multiple afferent (or sensing) and efferent (or effector) mechanisms exist to accomplish this homeostasis. The most important determinants of the osmolality or tonicity of the body fluids is the excretion or retention of water by the kidney, thirst mechanisms, and the intake of water. The serum sodium concentration is the laboratory test most often used clinically to assess tonicity. The pH of the body fluids and the major acid-base buffer systems are also carefully regulated. The lungs are responsible for the elimination of the carbon dioxide produced by cellular metabolism, and the kidneys excrete hydrogen ions and regulate the concentration of bicarbonate in the body fluids. Urinary net acid excretion, the hydrogen ions excreted as titratable acid and ammonium ions minus any bicarbonate, equals the acid added to the ECF from the diet and metabolism plus any fecal losses of alkali.

Water Relations of Several Arthropod Predators in the Peanut Agroecosystem

Water content and percentage of total body water (TBW) lost as a function of time was determined for four common predators in the peanut agroecosystem that may feed on the lesser cornstalk borer, Elasmopalpus lignosellus (Zeller) (Insecta: Lepidoptera: Pyralidae). TBW loss by Geocoris punctipes (Say) (Hemiptera: Lygaeidae), Reduviolus roseipennis Reuter (Hemiptera: Nabidae), and Oxyopes salticus Hentz (Aranae: Oxyopidae) increased linearly with desiccation time, but for workers of Solenopsis invicta Buren (Hymenoptera: Formicidae), it increased as a curvilinear function of desiccation time. Mortality of insects in a 24-h period was 69.4 and 80.6% for nymphal and adult G. punetipes, 16.7 and 58.1% for nymphal and adult R. roseipennis, 100% for S. invieta workers, and 14.7 and 13.0% for nymphal and adult O. saltieus. These high mortalities suggest that the lesser cornstalk borer is better able to survive xeric conditions than some of its common predators.

The Physiology of Dehydration Stress in the Land Crab, Cardisoma Carnifex: Respiration, Ionoregulation, Acid-Base Balance and Nitrogenous Waste Excretion

ABSTRACT Air-breathing Cardisoma carnifex, collected in Moorea, French Polynesia, were held in fresh water similar in chemical composition to that in their burrows. Under control conditions, which allowed branchial chamber flushing but not ventilation of the medium, crabs demonstrated net Na+ and Cl− uptake, and ammonia, urea and base excretion (= acidic equivalent uptake). Throughout 192 h of water deprivation, crabs dehydrated slowly at a rate of 0·55 gH2Okg−1 h−1, eventually reaching a near lethal 18% loss of total body water. Increases in haemolymph osmolytes were quite variable (0–29%); electrolyte excretion was negligible. and both decreased by approximately 55%, maintaining an unusually low gas exchange ratio (R = 0·53), and suggesting general metabolic depression. There was no evidence of internal hypoxia as haemolymph lactate remained at hydrated levels and actually increased. The dominant acid-base response was a progressive metabolic alkalosis accompanied by a partially compensating rise in . Alkalosis was probably caused by blockage of the normal aquatic excretion of base produced by the metabolism of this herbivore. Other possible causes were eliminated: i.e. alkalaemia due to contraction of the ECFV; entrainment via strong ion shifts; CaCO3 mobilization; and ammonia accumulation in the haemolymph. In the absence of water, net ammonia production and excretion both appeared to cease, and alternate end products (urea, uric acid) did not generally accumulate. Within 2h of rehydration, crabs regained more than half the lost water, and increased above control levels, and ammonia excretion and haemolymph concentration both exhibited a prolonged (56 h) 4- to 6-fold rise. At the same time, metabolic alkalosis was reversed in association with elevated net base excretion into the water; the latter was correlated with an increase in the strong ion difference (SID) flux ([Na+ + K+4-Ca2++Mg2+-Cl−]).

Volume influences on thirst and vasopressin secretion in dehydrated sheep.

The contribution of extracellular fluid volume (ECFV) to water consumption and plasma vasopressin concentration (PAVP) after water deprivation for 52 h was examined in sheep. Intravenous infusion of isotonic NaCl, equivalent to either estimated ECFV loss or total body water loss, significantly reduced water intake by 37% when water was offered 3 h after infusion but not when water was offered 1 h after infusion. Plasma osmolality (POsm) was reduced after 3 h. Infusion of 200 mM NaCl, which maintained POsm, decreased water consumption by the same degree as isotonic NaCl infusion. Thus large decreases in POsm had no effect on water intake in this experimental protocol. Lack of inhibition of drinking 1 h after infusion suggests that the decrease observed after 3 h may have been mediated by receptors in the interstitial fluid (ISF) compartment and not the intravascular compartment. PAVP was reduced 3 h after infusion of NaCl but not at 1 or 2 h after infusion. POsm was also decreased at 3 h. Thus reduction of PAVP by NaCl infusion may have been caused by either ISF or intracellular fluid volume expansion.

Water economy of Slughi, Canaan and Pointer dogs

Water economy was studied in five Slughi dogs (20·0 ± 1·7 kg) and four Canaan dogs (18·2 ± 3·4 kg), both native to the desert environment, and compared with that of three German Pointer dogs (26·8 ± 4·2 kg). The Slughi and Canaan dogs withstood longer periods of water deprivation during which they lost 1·75 per cent of their initial body mass per day. Loss from the Pointer was twice as great. In all breeds, the loss of fluid from the blood plasma exceeded the loss of total body water. Daily water intake was 31·7 ± 4·0 ml/kg/day in the Slughi, 33·2 ± 8·3 ml/kg/day in the Canaan and 54·5 ± 6·0 ml/kg/day in the Pointer dogs. Water expenditure was lower from all avenues in the desert breeds than in the Pointer, and low evaporative loss was very conspicuous. Economizing water seems to be the canid's main way of coping with water deprivation. The low metabolic rate measured in the dogs native to the desert environment implies a low rate of food consumption. This plays a major role in rendering the use of water by these animals more frugal than that of their non-desert relatives.

Effects of endurance exercise on metabolic water production and plasma volume.

Six endurance-trained and heat-acclimatized adult males ran for 1 h (or until exhaustion) at room temperature (23.8 degrees C) on three occasions. The work loads approximated 37, 56, and 74% of the subjects' aerobic capacities. Venous blood samples were drawn, and urine was collected before and immediately after each exercise bout. Metabolic cost was partitioned by energy substrate, and metabolic water production was quantified from urinary nitrogen, oxygen, and carbon dioxide production. Total body water loss was recorded as the decrease in body weight during the exercise. All subjects completed 1 h of exercise at the two lower exercise intensities but, due to exhaustion, averaged only 35.5 min at the highest work intensity. There were no significant changes in plasma volume after the exercise bouts. Metabolic water production increased with increasing work intensity as did the fraction of total caloric expenditure derived from carbohydrate metabolism. Plasma protein content significantly increased at all levels of exercise intensity. Metabolic water production alone would be of minimal help in plasma volume maintenance and thermoregulation during endurance exercise.

Role for glucagon as a mineralocorticoid antagonist during the fetal-perinatal period

The progressive decrease in total body water (TBW) and sodium during the fetal-perinatal period; the normally noted 5–10 per cent largely water weight loss noted in term infants during the first 3–4 days postnatally; and, the even greater TBW and sodium losses incurred by premature infants during the initial post-natal week may, in part, be secondary to a glucagon-mediated, renal distal tubular hyporesponsiveness to aldosterone.

Compartmental body composition of cancer patients by measurement of total body nitrogen, potassium, and water

Quantitative measurement was made of body composition in patients with several forms of neoplastic disease. Total body nitrogen was determined by means of the prompt gamma neutron activation technique; total body potassium was measured with the use of a whole body counter. The mass and protein content of the muscle compartment and nonmuscle lean tissue were estimated by application of the technique of compartmental analysis. Total body water, determined simultaneously with the use of tritium label, provided a measure of lean body mass. From these data, the body fat can be inferred. The prompt gamma neutron activation and whole body counting techniques represent a considerable advance over the balance and radioisotope techniques used in earlier studies. The new techniques make possible sequential studies over prolonged periods of time with a considerable degree of accuracy. The loss of body weight by patients with solid tumors consisted primarily of the loss of muscle mass and body fat. Even in severe wasting, the patients appear to retain significant amounts of body fat. It is the skeletal muscle which is predominantly lost; the visceral life-supporting system is, to a considerable extent, spared. The nonmuscle tissue including the visceral fraction did not change in this study, and actually appeared to increase in size when comparison was made with the normal contrast population. The loss of total body water was slight in the cancer patients studied.

Plasma water shifts during thermal dehydration.

Changes in body water compartments during acute dehydration before and after acclimation to heat and the role of plasma proteins in body fluid dynamics were studied in the rat. Compartment volumes, plasma and interstitial protein concentrations, and colloid osmotic pressures (COP) were measured in anesthetized (with thiopental sodium) and, if necessary, nephrectomized rats. Albumin outfluxes, total protein mass (TPM), and total albumin mass (TAM) were calculated. Nonacclimated rats conserved plasma volume (PV) as long as dehydration did not exceed 15-16% body weight loss (18.6% total body water loss). This was associated with decreased albumin outflux, elevated plasma COP, and reduced subcutaneous COP. When water loss reached 25,5%, PV and extracellular fluid volume decreased by 45 and 34%, respectively. Albumin outflux recovered, TPM and TAM decreased, and plasma COP remained high. In acclimated dehydrated rats PV remained unchanged, albumin outflux decreased, TPM and COP increased, and interstitial COP decreased. Most of the water loss was intracellular in origin. It was concluded that PV changes during dehydration are related to changes in plasma protein distribution. PV conservation rate is different in rats as compared to desert PV conservers.

Some effects of dehydration on internal distributions of water and solutes in Xenopus laevis

1. 1. In relation to body weight changes resulting from evaporative water losses of up to 37% of initial body weight: 1.1. (a) Plasma chloride and potassium concentrations increased in proportion to total body water losses. 1.2. (b) Plasma urea concentrations increased at greater rates than expected from the sum of basal synthesis and dehydration. 1.3. (c) Plasma sodium concentrations initially increased less rapidly than expected from total body water losses, but by losses of 30% of initial body weight closely approximated predicted concentrations. 1.4. (d) Plasma volumes decreased slightly faster than expected, while hematocrits increased as expected. 2. 2. Skeletal muscles and the ventricular muscles of the heart retained water to greater degrees than expected. Dehydration did not elicit net shifts in Na + K +, Cl − or amino acids between the intracellular and extracellular compartments in either skeletal muscle or ventricle.

Water and sodium balance in the estuarine diamondback terrapin (Malaclemys)

Total body water decreased significantly in terrapins exposed to sea water (SW). Although the intracellular fluid decreased somewhat upon SW exposure, the decline in extracellular fluid was almost twice as great. Under conditions of voluntary drinking after salt loading, terrapins substantially increased the volume of the extracellular fluid while maintaining the intracellular fluid near the freshwater (FW) control levels. FW terrapins were consistently heavier than animals of the same plastron length exposed to SW. Thus expression of body fluid volumes as ml/cm plastron length rather than as % body weight is necessary to correct for the loss of total body water with progressive dehydration. Fasted terrapins in SW lost weight at 0.32% weight/day, whereas the rate in FW was 0.21%/day. Water influx and efflux in SW were 0.17 and 0.16 ml/100 g·h respectively. When the efflux was increased by the calculated value for unmeasured respiratory loss, it exceeded the influex by 0.01 ml/100 g·h. Consequently the net water loss determined with radiotracers (equivalent to 0.24% weight/day) was similar to the difference between the weight losses in SW and FW (0.11%/day). Partitioning studies indicated that the majority of water exchange between the terrapin and SW occurs through the integument. Terrapins in SW underwent a concentration of the body fluids, most of which can be attributed to water loss, not electrolyte gain. The rates of Na influx and efflux were quite low (usually ranging from 6–10 μmoles/100 g·h). In two terrapins the injection of NaCl loads resulted in eight- to 19-fold increases in Na efflux. The uptake of Na from SW occurred orally. The skin was virtually impermeable to Na. The salt gland and possibly the cloaca were the major routes of Na efflux. The injection of NaCl loads resulted in an increase in cephalic Na excretion from a mean of 3.2 μmoles/100 g·h to 32.5 μmoles/100 g·h. Terrapins in SW exhibited a significant increase in bladder urine [K] over the FW controls. There was a direct relationship between plasma [Na], urine [K], and lachrymal salt gland Na−K ATPase content. In comparing SW terrapins with FW painted turtles (Chrysemys) exposed to SW radiotracer studies demonstrated a similarity in Na influx, but there was at least a four-fold increase in water exchange in the painted turtle. It seems likely that the skins of many aquatic reptiles (marine, estuarine and FW) are impermeable to Na but differ markedly in water permeability.

Water balance and humidity preference in three species of ticks.

Comparisons were made between the abilities of 3 species of ticks, Amblyomma americanum (L.), A. maculatum Koch, and Dermacentor variabilis Say to resist dehydration and maintain water balance. Of the 3 species, A. americanum appears most dependent on moist microenvironments because of its greater susceptibility to percentage losses of total body water and drop in hemolymph volume at low humidities. This species appears to counteract these losses as adults by seeking environments with relative humidities above its critical equilibrium humidity (CEH). It does so very efficiently after water losses of ca 10–15% of its beginning weight. Although A. maculatum loses percentage water reserves less rapidly, it apparently is also dependent on relatively moist habitats because of its high critical equilibrium humidity (92–93% rh). By comparison, D. variabilis loses percentage water reserves at about the same rate as A. maculatum ; but because of its intermediate size (6.74 mg and 5.41 mg in females and males, respectively, versus 9.80 mg and 8.70 mg in A. maculatum and 4.47 and 2.77 mg in A. americanum ), it loses the least absolute amounts of water when exposed to the same desiccating conditions. The hemolymph volume percentage in females of D. variabilis is little different in ticks held at 93% and 30% rh, despite an approximate 10% greater weight loss in ticks held at 30% for 16 days. Large numbers of this species also seek out humidities above the CEH (84–85% rh) when the percentage weight losses approach 10–15% of body weight. The hemolymph volume percentage was lower in A. maculatum (at all experimental conditions) than in both A. americanum and D. variabilis . The above data suggest that there may be some correlation between the “normal” geographical distributions of the 3 species studied and their abilities to resist dehydration and maintain water balance.