Mode Of Rehydration Research Articles

The Effects of Mode of Rehydration on Subsequent Exercise-heat Challenge Performance

The Effects of Mode of Rehydration on Subsequent Exercise-heat Challenge Performance

G38(P) The challenge of change

IntroductionGastroenteritis poses a major burden for health services. National Accident Emergency Medical guidelines for acute gastroenetritis in children provide a clear, safe guideline to instruct assessment and treatment of acute...

The Effect of Oral Vs. Intravenous Rehydration on Circulating Myoglobin and Creatine Kinase

Physical activity of significant intensity and duration may cause varying degrees of skeletal muscle damage, but it is unclear whether mode of rehydration will attenuate muscle tissue disruption caused by exercise in the heat. To examine the effects of the mode of rehydration on markers of muscle damage (myoglobin and creatine kinase [CK]), 11 healthy active men (age = 23 +/- 4 years, body mass = 80.9 +/- 3.9 kg, height = 180.5 +/- 5.4 cm) completed 4 experimental trials consisting of an exercise dehydration protocol (to -4% of baseline body mass), followed by a rehydration period (oral, intravenous [IV], oral and IV combined, and ad libitum), and finishing with an intense exercise challenge that included treadmill running and sprinting and a box lifting protocol. During rehydration, subjects returned to -2% of baseline body mass unless completing the ad libitum trial during which they consumed fluids as thirst dictated. Myoglobin (Mb) and CK were measured during euhydrated rest. Post-exercise blood was drawn at 1 and 24 hours post exercise challenge for Mb and CK, respectively. Urine was collected during euhydrated rest and 1-hour post exercise challenge for measurement of Mb clearance. Mb concentrations increased significantly from pre (1.06 +/- 0.20, 0.88 +/- 0.07, 1.15 +/- 0.25 and 0.92 +/- 0.06 nmol.L) to post (1.52 +/- 0.28, 1.44 +/- 0.11, 1.71 +/- 0.45 and 1.58 +/- 0.39) for IV, oral, oral and IV combined, and ad libitum, respectively, but were not significantly different among trials. Serum CK concentrations remained within the normal physiological range for all trials. Thus, despite previous research that clearly indicates the benefit of ingesting fluids during exercise to attenuate muscle damage, there were no significant differences between the modes of rehydration on circulating Mb and CK.

Desiccation of somatic embryos of Cyclamen persicum Mill.

SummaryTo achieve storable somatic embryos (SE) of Cyclamen persicum, different desiccation conditions and two rehydration methods were tested. Somatic embryos derived from liquid cultures were dried in various relative humidities (r.h.) using desiccators filled with saturated salt solutions. Embryos dried to moisture contents of 24% and higher were able to germinate. For germination of the dried somatic embryos, the mode of rehydration was crucial. Only after imbibition in liquid hormone-free medium tubers were cotyledons and roots formed. Drying in decreasing r.h. (91–57–18%) resulted in low moisture contents of 12% on average, comparable with that found in seeds. Depending on the quality of somatic embryos significant differences were observed between different experiments. Somatic embryos with a high dry-matter content showed germination rates of 60% after desiccation in decreasing r.h. Germinating embryos formed bigger tubers than non-dried controls and developed cotyledons of better quality.

Modalités de réhydratation des diarrhées aiguës du nourrisson à l’hôpital. Impact de la présence permanente d’un pédiatre et d’une structure d’hospitalisation de courte durée

Diarrheal diseases account for 10% of hospitalizations in infants, and large differences in rates of hospitalization have been reported. Objective. – To analyze hospital treatment of infants with acute gastroenteritis, especially the variations in modes of rehydration, hospitalization rates and lengths of stay, related to paediatrician permanency with a short-stay observation unit at their disposal. Methods. – This prospective multicentric study during two rotavirus epidemic periods included 1,187 infants (mean age 10 ± 6 months) with acute gastroenteritis resulting or not in dehydration. During the first period, 12 volunteer hospitals were included. During the second period, we compared six (among the 12) hospitals where infants were admitted in emergency care or pediatric units without pediatric 24-h permanency, with a pediatric emergency care unit having pediatric permanency with a short-stay observation unit. Results. – During the first period, 32% were dehydrated and 6% had hypovolemic shock on admission. The hospitalization rate was 81%. Only 19% of dehydrated infants had exclusively oral rehydration, and 19% of normohydrated infants had intravenous rehydration. During the second period, the hospitalization rate was 42% in the pediatric emergency care unit (28% in the short-stay unit and 14% in hospitalization units) versus 77% in the six hospitals. In the pediatric emergency care unit as compared to the six hospitals, there were a reduction of 65% of hospitalization days, 58% of intravenous accesses, and 66% of laboratory tests. Conclusion. – Our findings suggest that a paediatric permanency with a short-stay observation unit at their disposal improves quality of treatment and is cost-effective.

INTRAVENOUS VERSUS ORAL REHYDRATION DURING A BRIEF PERIOD: STRESS HORMONE RESPONSES TO SUBSEQUENT EXHAUSTIVE EXERCISE IN THE HEAT

1614 The purpose of this study was to determine if intravenous fluid rehydration (RHY), versus oral RHY, during a brief period (20 min) differentially affects plasma ACTH, cortisol, and norepinephrine concentrations during subsequent exhaustive exercise in the heat. It was hypothesized that these hormonal variables at exhaustion would show unique perturbations due to the different modes of RHY. Following dehydration (DHY) to −4% of body weight eight nonacclimated highly trained males (Age- 23.5 ± 1.2 years, VO2peak- 61.4 ± 0.8ml·kg·min−1, % body fat- 13.5 ± 0.6%) cycled to exhaustion at 74% VO2peak in 36.8°C on three different occasions. These included: 1) CONTROL, no fluid was provided during the RHY period, 2) DRINK, oral RHY (0.45% NaCl) was provided equal to 50% of the prior DHY, and 3) IV, intravenous infusion (0.45% NaCl) was provided equal to 50% of the prior DHY. Thus, in the two RHY treatments, subjects began exercise at −2% DHY, while in the CONTROL trial subjects began exercise at −4% DHY. Exercise time to exhaustion was not different (p = 0.08) between the DRINK (34.86 ± 4.01 min) and IV (29.48 ± 3.50 min) trials, but both were longer (p < 0.05) than the CONTROL (18.95 ± 2.73 min) trial. No differences (p > 0.05) were found for any of the hormone measures among trials. For all trials the following within responses were reported. Post-exercise (POE) plasma ACTH values were higher (p < 0.05) than post-DHY and pre-exercise (PRE) values. Plasma cortisol PRE was lower (p < 0.05) compared to post-DHY and POE values. POE plasma norepinephrine values were higher (p < 0.05) compared to post-DHY and PRE values. Thus, the endocrine responses at exhaustion were similar regardless of hydration state and mode of RHY, but RHY prolonged the time to exhaustion. Supported by General Nutrition Corp. & Univ. of Conn. Research Foundation

Bacterial adhesion to sausage casings: development of a model experimental system

An experimental system was developed to study bacterial adhesion to cooked sausages, using natural sheep casing, 100% collagen casing, or collagen-sorbitol-cellulose casing as model surfaces. Square pieces ( c. 1 cm 2) of the casings were inserted into specially designed flow chambers. Bacteria were introduced ( c. 10 8 cfu ml −1) and allowed to sediment on the casings for 20 min. The chambers were then rinsed under controlled conditions (shear stress of 0·05 N m −2) and the remaining (adherent) bacteria were stained and enumerated under light microscopy. Typically, Brochothrix thermosphacta cells adhered to casings in large numbers ( c. 10 5 cfu cm −2), regardless of the casing type and mode of rehydration (30 min in water or 5 min in a 10% NaCl solution; room temperature). A Lactobacillus sp. was found to adhere to the casings in lower numbers ( c. 10 4 cfu cm −2) and this was due to a low level of sedimentation rather than to weak adhesive properties. Preliminary results indicate that the method developed will be applicable to pieces of casings peeled from cooked sausages.

Vascular fluid shifts and endocrine responses to exercise in the heat. Effect of rehydration.

This study examines the relationships between vascular changes and endocrine responses to prolonged exercise in the heat, associated with dehydration and rehydration by fluids of different osmolarity. Five subjects were exposed, in a 34 degrees C environment for 4 h of intermittent exercise on a cycle ergometer at 85 +/- 12 Watts (SD). Fluid regulatory hormones and cortisol were analysed in 3 experimental sessions: one without any fluid supplement (NO FLUID), and two with progressive rehydration, either by spring water (WATER) or isotonic solution (ISO), given after 70 min of exercise. Results were expressed in terms of differences between the mean values observed at the end of the exercise and the first hour values taken as references. Dehydration (NO FLUID) elicited a 4.0 +/- 0.8% (SE) decrease in plasma volume (PV) and an increase in osmolarity (8.4 +/- 3.1 mosmol X l-1). Concomitantly, plasma aldosterone (PA), renin activity (PRA), arginin vasopressin (AVP) and cortisol (PC) levels increased greatly in response to exercise in the heat (PA: 37.2 +/- 10.8 ng. 100 ml-1; PRA: 13.4 +/- 2.5 ng X ml-1 X h-1; AVP: 3.8 +/- 1.3 pg X ml-1; PC: 12.2 +/- 2.7 micrograms X 100 ml-1). Rehydration with water led to decreased osmolarity (-8.2 +/- 2.1 mosmol X l-1) with no significant changes in PV. With ISO, PV increased by 6.0 +/- 1.3% and the decrease in osmolarity was-5.8 +/- 1.8 mosmol X l-1. With both modes of rehydration, the increases in PRA, AVP and cortisol were blunted; only ISO prevented the rise in PA.(ABSTRACT TRUNCATED AT 250 WORDS)

Some factors affecting the survival of airborne viruses.

SUMMARY The response of aerosolized viruses to relative humidity depended greatly on the composition of the fluid from which the viruses were sprayed. For example, the removal of salts from the spray fluid diminished the loss of infectivity of Langat virus (a group B arbovirus) at intermediate relative humidities. Salts were less toxic towards aerosolized Semliki Forest virus (a group A arbovirus) but did cause some loss of infectivity at higher relative humidities after prolonged storage of the aerosol. Polyhydroxy-compounds reversed the virucidal effects of salts on arboviruses. The removal of protein from the spray suspensions of arboviruses caused rapid loss of infectivity in the aerosol at very high relative humidities but had no detrimental effect at lower relative humidities. Poliovirus and T coliphage, which possess no structural lipid, retained high levels of infectivity following aerosolization at relative humidites of 70% or above; at lower relative humidities they were inactivated rapidly. This rapid inactivation was increased further at lower solute concentrations of the spray fluid. The infectivities of aerosolized polioviruses and coliphages depended on the mode of rehydration during collection of the aerosols, but the infectivities of arboviruses in aerosols were unaffected by this. Atmospheric oxygen was not toxic to viruses in the aerosol state.

68. Survival of escherichia coli freeze-dried at −40°C: Interaction of additive, degree of drying, thermal regimen, and mode of rehydration: G. R. Orndorff and A. P. MacKenzie (Cryobiology Research Institute, American Foundation for Biological Research, Madison, Wisconsin)

68. Survival of escherichia coli freeze-dried at −40°C: Interaction of additive, degree of drying, thermal regimen, and mode of rehydration: G. R. Orndorff and A. P. MacKenzie (Cryobiology Research Institute, American Foundation for Biological Research, Madison, Wisconsin)