Soup Kettle Topics: Hydration – General

Title: Acute Effect of Sodium Cromoglycate on Airway Narrowing Induced by 4.5 Percent Saline Aerosol. Outcome before and During Treatment with Aerosol Corticosteroids in Patients with Asthma
Author: Anderson, S. D.; du Toit, J. I.; Rodwell, L. T.; Jenkins, C. R.; (Date: Mar, 1994)
Journal: Chest; V. 105; Issue: 3; Pages: 673-80

Abstract: STUDY OBJECTIVE: To investigate the acute effect of sodium cromoglycate on airway responses to 4.5 percent saline aerosol challenge, before and during treatment with inhaled budesonide–a corticosteroid. DESIGN: Open study, with a total of five visits, two before budesonide treatment, and three follow-up visits, two between 5 and 6 weeks and one at more than 11 weeks. SETTING: Referral-based Respiratory Investigation Unit at Royal Prince Alfred Hospital, a major Sydney-based teaching hospital. PATIENTS: Eleven patients with asthma (ten atopic), with a PD20 FEV1 to 4.5 percent saline aerosol challenge and about to commence inhaled budesonide for treatment of their asthma. INTERVENTIONS: The 40 mg of sodium cromoglycate was inhaled before a 4.5 percent NaCl challenge, both before and after regular (36 +/- 9 d) treatment with budesonide (1,000 micrograms/d). The final challenge was repeated in ten subjects after 11 weeks or more of treatment with budesonide. MEASUREMENTS AND RESULTS: Sensitivity to 4.5 percent saline aerosol was measured as the dose of saline aerosol required to induce a 20 percent fall in FEV1 (PD20). Reactivity was measured as the dose-response slope by taking the percent fall in FEV1 and dividing it by the dose required to induce the fall. On the control day the geometric mean PD20 (95 percent CI) for 4.5 percent saline aerosol was 2.8 (1.4 to 5.4) and the dose response slope (DRS) 5.6 (2.9-11.1). An acute dose of sodium cromoglycate reduced sensitivity (PD20) by 8-fold and reactivity (DRS) 12.3-fold. This effect was similar in magnitude to that measured after regular treatment with budesonide alone. When sodium cromoglycate was given during treatment with budesonide, the PD20 was reduced 16-fold and the DRS 42-fold, and this was greater than the reduction with budesonide taken for 3 months (p < 0.03, p < 0.05 respectively). CONCLUSIONS: Sodium cromoglycate inhibits responses to 4.5 percent saline aerosol and has additional benefits to those conferred by aerosol steroids. The mechanism for responsiveness to saline aerosol and efficacy of these drugs may relate to alteration in chloride ion channel regulation by inflammation.
Notes: Clinical Trial
Journal Article
Author Address: Department of Respiratory Medicine, Royal Prince Alfred Hospital, Camperdown, Australia.


Title: Activation of Ion Transport Systems During Cell Volume Regulation
Author: Eveloff, J. L.; Warnock, D. G.; (Date: Jan, 1987)
Journal: Am J Physiol; V. 252; Issue: 1 Pt 2; Pages: F1-10

Abstract: This review discusses the activation of transport pathways during volume regulation, including their characteristics, the possible biochemical pathways that may mediate the activation of transport pathways, and the relations between volume regulation and transepithelial transport in renal cells. Many cells regulate their volume when exposed to an anisotonic medium. The changes in cell volume are caused by activation of ion transport pathways, plus the accompanying osmotically driven water movement such that cell volume returns toward normal levels. The swelling of hypertonically shrunken cells is termed regulatory volume increase (RVI) and involves an influx of NaCl into the cell via either activation of Na-Cl, Na-K-2Cl cotransport systems, or Na+-H+ and Cl(-)-HCO3- exchangers. The reshrinking of hypotonically swollen cells is termed regulatory volume decrease (RVD) and involves an efflux of KCl and water from the cell by activation of either separate K+ and Cl-conductances, a K-Cl cotransport system, or parallel K+-H+ and Cl(-)-HCO3- exchangers. The biochemical mechanisms involved in the activation of transport systems are largely unknown, however, the phosphoinositide pathway may be implicated in RVI; phorbol esters, cGMP, and Ca2+ affect the process of volume regulation. Renal tubular cells, as well as the blood cells that traverse the medulla, are subjected to increasing osmotic gradients from the corticomedullary junction to the papillary tip, as well as changing interstitial and tubule fluid osmolarity, depending on the diuretic state of the animal. Medullary cells from the loop of Henle and the papilla can volume regulate by activating Na-K-2Cl cotransport or Na+-H+ and Cl(-)-HCO3- exchange systems. Both Na-Cl and Na-K-2Cl cotransport systems have been identified in the medullary Loop of Henle and it is postulated that the Na-K-2Cl cotransport system predominates during RVI and affects transepithelial NaCl transport while the Na-Cl cotransport system may function during RVD in these cells.
Notes: Journal Article
Review


Title: Cell Volume in the Regulation of Hepatic Function: A Mechanism for Metabolic Control
Author: Haussinger, D.; Lang, F.; (Date: Dec 12, 1991)
Journal: Biochim Biophys Acta; V. 1071; Issue: 4; Pages: 331-50

Notes: Journal Article
Review
Review, Academic
Author Address: Medizinische Universitatsklinik, Freiburg, Germany.


Title: Metabolic Effects of Water Deprivation
Author: Hohenegger, M.; Laminger, U.; Om, P.; Sadjak, A.; Gutmann, K.; Vermes, M.; (Date: May, 1986)
Journal: J Clin Chem Clin Biochem; V. 24; Issue: 5; Pages: 277-82

Abstract: Under the conditions of pair feeding, water-deprived rats predominantly use fat as a metabolic fuel, whereas total energy turnover as measured by oxygen consumption is not altered. Plasma free fatty acids are elevated in dehydrated rats, indicating enhanced lipolysis. Reduced hepatic fatty acid synthesis and reduced triacylglycerol secretion into the blood seem to be the main factors for the decrease of plasma triacylglycerol, observed 48 hours after the onset of water deprivation. Enhanced plasma levels of corticosterone (about 100%) and glucagon (about 50%) may contribute to the metabolic situation observed in water deprivation.
Notes: Journal Article


Title: Oral Water Intoxication in Infants. An American Epidemic
Author: Keating, J. P.; Schears, G. J.; Dodge, P. R.; (Date: Sep, 1991)
Journal: Am J Dis Child; V. 145; Issue: 9; Pages: 985-90

Abstract: Between 1975 and 1990, a total of 34 patients with water intoxication were treated at St Louis (Mo) Children’s Hospital, 24 of these in the last 3 years, indicating a marked increase in incidence of this previously rare condition. Thirty-one were infants living in poverty who ingested excessive amounts of water offered at home by their caretakers. Exhaustion of the supply of infant formula was the most common reason given for this substitution. Infants were treated by a single infusion of hypertonic saline or a slow infusion of isotonic saline. Central pontine myelinolysis was not observed as a complication of hypertonic saline therapy. Modification of the Special Supplemental Food Program for Women, Infants, and Children to provide sufficient formula for the growing infant and better education of mothers as to the hazards of excessive water ingestion might reduce the incidence of this preventable and life-threatening condition.
Notes: Journal Article
Author Address: Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine, St Louis, Mo.


Title: Water: An Essential but Overlooked Nutrient
Author: Kleiner, S. M.; (Date: Feb, 1999)
Journal: J Am Diet Assoc; V. 99; Issue: 2; Pages: 200-6

Abstract: Water is an essential nutrient required for life. To be well hydrated, the average sedentary adult man must consume at least 2,900 mL (12 c) fluid per day, and the average sedentary adult woman at least 2,200 mL (9 c) fluid per day, in the form of noncaffeinated, nonalcoholic beverages, soups, and foods. Solid foods contribute approximately 1,000 mL (4 c) water, with an additional 250 mL (1 c) coming from the water of oxidation. The Nationwide Food Consumption Surveys indicate that a portion of the population may be chronically mildly dehydrated. Several factors may increase the likelihood of chronic, mild dehydration, including a poor thirst mechanism, dissatisfaction with the taste of water, common consumption of the natural diuretics caffeine and alcohol, participation in exercise, and environmental conditions. Dehydration of as little as 2% loss of body weight results in impaired physiological and performance responses. New research indicates that fluid consumption in general and water consumption in particular can have an effect on the risk of urinary stone disease; cancers of the breast, colon, and urinary tract; childhood and adolescent obesity; mitral valve prolapse; salivary gland function; and overall health in the elderly. Dietitians should be encouraged to promote and monitor fluid and water intake among all of their clients and patients through education and to help them design a fluid intake plan. The influence of chronic mild dehydration on health and disease merits further research.
Notes: Journal Article
Review
Review, Academic
Author Address: Nutritional Sciences Program, University of Washington, Seattle, USA.


Title: Thermally Induced Asthma and Airway Drying
Author: McFadden, E. R., Jr.; Nelson, J. A.; Skowronski, M. E.; Lenner, K. A.; (Date: Jul, 1999)
Journal: Am J Respir Crit Care Med; V. 160; Issue: 1; Pages: 221-6

Abstract: The purpose of this study was to determine whether mucosal dehydration causes thermally induced asthma. To provide data on this point, we studied the effects on lung function of progressive water loss (WL) from the respiratory tract by having eight subjects perform isocapnic hyperventilation for 1, 2, 4, and 8 min at a constant level (V E = 57.5 +/- 6.3 L/min [mean +/- SEM]) while they breathed dry air at frigid (TI = -12.5 +/- 2.7 degrees C) (cold trial) and ambient (24.3 +/- 0.7 degrees C) (warm trial) temperatures. Expired temperatures (TE) were continuously monitored, and WL from the intrathoracic airways was calculated from published relationships. FEV1 was measured before and after each challenge. Each inspirate produced stimulus-response decrements in FEV1, but the effect of cold air was greater (% Delta cold8min = 30.0 +/- 4.7%, warm = 16.0 +/- 4.4%; p = 0.01). Water loss, however, was significantly less in the cold experiment because TE was lower (WL cold8min = 4.8 +/- 0.4 g, warm = 7.1 +/- 0.7 g; p = 0.001; TE cold8min = 22.8 +/- 2.3 degrees C, warm 30.9 +/- 1.5 degrees C; p = 0.003). The FEV1 decreased as WL rose, but the largest intrathoracic losses were associated with the smallest obstructive response (% DeltaFEV1 cold8min = 30%, WL = 4.7 mg; % DeltaFEV1 warm8min = 16%, WL = 7.1 mg; p = 0.002). These data show that removal of water from the lower respiratory tract, and by inference the development of a hyperosmolar periciliary fluid, do not appear to be the primary causes of thermally induced asthma.
Notes: Journal Article
Author Address: Division of Pulmonary and Critical Care Medicine, University Hospitals of Cleveland, Cleveland, Ohio, USA. erm2@po.cwru.edu


Title: Hypohydration During Exercise in Children: Effect on Thirst, Drink Preferences, and Rehydration
Author: Meyer, F.; Bar-Or, O.; Salsberg, A.; Passe, D.; (Date: Mar, 1994)
Journal: Int J Sport Nutr; V. 4; Issue: 1; Pages: 22-35

Abstract: This study examined changes in children’s thirst and drink preferences during exercise-induced hypohydration and their spontaneous rehydration during a 30-min recovery. Twenty-four 9- to 13-year-old children (14 females, 10 males) participated in four intermittent 90-min cycling sessions in the heat (35 degrees C, 20% relative humidity); the sessions differed in the drinks the children were sampling (apple, orange, water, and grape). Thirst and drink preferences were assessed (analog and category scales) while children dehydrated up to about 0.76% of their initial body weight. During 90 min dehydration, there was an increase in thirst intensity for all drinks. The grape was the preferable drink throughout the dehydration phase, but its desirability did not increase as much as the desirability of the orange, apple, and water drinks. During the 30-min recovery, most subjects rehydrated spontaneously, exceeding baseline levels by 0.76 +/- 0.15% (M +/- SEM) for grape, 0.40 +/- 0.15 for apple, 0.71 +/- 0.18 for orange, and 0.48 +/- 0.16 for water. Although full rehydration was achieved with all drinks, the magnitude of rehydration was statistically greater with grape and orange than water and apple (p < .05). It was concluded that mild hypohydration during exercise increased children’s thirst and drink desirability. In general, spontaneous overshoot of fluid consumption occurred during recovery.
Notes: Journal Article
Author Address: Department of Pediatrics, Children’s Exercise and Nutrition Centre, McMaster University, Hamilton, ON, Canada.


Title: Drink Composition and the Electrolyte Balance of Children Exercising in the Heat
Author: Meyer, F.; Bar-Or, O.; MacDougall, D.; Heigenhauser, G. J.; (Date: Jun, 1995)
Journal: Med Sci Sports Exerc; V. 27; Issue: 6; Pages: 882-7

Abstract: Twelve 9- to 12-year-old children (6 boys, 6 girls) performed four exercise-in-heat (35 degrees C, 45% RH) trials which differed in the composition of the fluids they drank. In each trial, subjects cycled for one 20-min and two 15-min bouts at 50% peak VO2 with 10-min rest periods in between. In a fourth bout, they cycled at 90% peak VO2 until exhaustion. Drinks had the same grape flavor and were assigned in a double-blind design and in a Latin-square order. Subjects drank 7 ml.kg-1.h-1 to keep them euhydrated. Three of the drinks had 6% carbohydrates (CHO), with different [Na+]: 0, 8.8, 18.5 mmol.l-1 and one drink had neither CHO nor Na+ (WATER). Among drink trials, there were no differences in the increase in rectal temperature, HR, or performance time to exhaustion. Despite the larger Na+ deficit induced by the Na(+)-free drinks compared with the Na+ drinks (11.8 +/- 1.4 vs 5.7 +/- 0.9 mmol.h-1), neither plasma [Na+] nor osmolality were affected. These results suggest that electrolyte, as in the above conditions, did not affect electrolyte balance, thermoregulatory responses, or aerobic performance of children exercising in the heat. The greater Na+ deficit induced by ion-free drinks was of minor biological importance.
Notes: Clinical Trial
Controlled Clinical Trial
Journal Article
Author Address: Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada.


Title: Another Look At: Fuel + O2 –> Co2 + H2o. Developing a Water-Oriented Perspective
Author: Stookey, J. D.; (Date: Apr, 1999)
Journal: Med Hypotheses; V. 52; Issue: 4; Pages: 285-90

Abstract: Water plays many vital roles which must be maintained despite constant threat of water stress from the environment. Mechanisms to maintain these roles over the long-term involve intermediates of many metabolic pathways, such as glycerol, sucrose, free amino acids and their derivatives. In addition to viewing metabolic products as intermediates along energy-related pathways, nutrition researchers and epidemiologists should consider them as determinants of intracellular fluid maintenance. Satiety processes, oxidative-fuel selection, hormonal control, and intracellular-signaling processes can all be interpreted in terms of water-oriented metabolism. Water intake and hydration status can vary considerably, and may be inadequate for a sizeable proportion of Western adults. Due to the metabolic adaptations required to compensate for perpetually inadequate water, chronic sub-optimal water intakes may be highly relevant to chronic disease etiology. Preliminary evidence links water-oriented metabolism to obesity, diabetes, cardiovascular disease, hypertension and cancer. Development of a water-oriented perspective may reveal an important new area of research in human nutrition and epidemiology.
Notes: Journal Article
Author Address: University of North Carolina, Chapel Hill, USA.

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