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PubMed1999

Electrolyte vs. glucose-electrolyte isotonic solutions for oral rehydration therapy in horses.

An isotonic electrolyte solution with a composition similar to equine sweat was compared to an isotonic glucose-glycine-electrolyte solution for oral rehydration therapy in exercising horses. Ten horses were dehydrated by using frusemide and allocated randomly to receive 4 different oral solutions: isotonic sweat-like electrolyte solution, half-strength hypotonic electrolyte solution, isotonic glucose-glycine-electrolyte solution, and plain water. Solutions were given by nasogastric tube using the same volume as the bodyweight lost by each horse. Blood samples were collected before and throughout 6 h of the rehydration period. Results showed that all solutions recovered pre-frusemide values of packed cell volume (PCV) and total plasma protein (TP) in a similar fashion. No changes for Na+ values were observed during the rehydration period when the isotonic sweat-like solution was used. However, a significant hyponatraemia was induced throughout rehydration when the other 3 solutions were given, especially when hypotonic solution and water were used. Osmolality values did not change when both isotonic solutions were administered; but a significant hypotonicity was observed when hypotonic solution and water were given. When the isotonic sweat-like solution was used, plasma Cl-, K+ and creatinine values recovered to premedication values significantly faster than the other 3 solutions. In conclusion, the isotonic sweat-like electrolyte was the best solution because it restored rapidly the fluid and plasma electrolyte imbalances. In contrast, the isotonic glucose-glycine-electrolyte solution impaired the plasma electrolyte imbalances.

Animals↗
PubMed1987

The effect of non-isotonic solutions on human isolated airway smooth muscle.

In patients with asthma, bronchoconstriction can be provoked by the inhalation of aerosols of non-isotonic solutions. In order to determine if this bronchoconstriction results from a direct effect on airway smooth muscle we decided to examine the effects of non-isotonic solutions on the resting tone of human isolated bronchi and on responses to carbachol, histamine and field stimulation. Human bronchi were obtained from thoracotomy and dose-response relationships for each agonist were obtained for bronchial rings suspended in isotonic Krebs-Henseleit solution (290 mOsm). A second curve was then obtained with half the rings immersed in a solution made hypotonic (145 mOsm) or hypertonic (440 mOsm) by the addition of NaCl or salts and glucose. The other half remained in isotonic solutions as controls. In a separate series of experiments, field stimulation responses to a submaximal frequency (15 Hz) were measured before and after a change from isotonic to non-isotonic bathing solution. The resting tone of the preparations was transiently reduced by hypertonic solutions and increased by hypotonic solutions. Contractile responses to agonists were significantly diminished by non-isotonic solutions. Agonist potency was unaffected by hypertonic solutions but the potency of carbachol was reduced by hypotonic solutions. Responses to field stimulation were unaffected by the hypertonic solution but reduced by the hypotonic solution. We conclude that the bronchoconstrictor actions of non-isotonic solutions and their effects on airway reactivity are unlikely to be due to direct effects on airway smooth muscle.

Bronchi↗
PubMed1980

Osmotic lysis of bovine chromaffin granules in isotonic solutions of salts of weak organic acids. Release of catecholamines, ATP, dopamine beta-hydroxylase, and enkephalin-like material.

Chromaffin granules in isotonic solutions of K+ CH3COO- (acetate), K+ CH3CHOHCOO- (lactate), and K+2-OOCCH2CH2COO- (succinate) are stable at pH 7 but release 40 to 80% of their soluble contents of catecholamines, ATP, and dopamine beta-hydroxylase when the medium pH is less than 6. Enkephalin-like material which has recently been shown to co-sediment with chromaffin granules in sucrose density gradients is also released at low pH. The release of ATP and enkephalin-like material is proportional to the release of catecholamine. The release of soluble constituents of chromaffin granules is inhibited by increasing the osmolality of the solution with sucrose. Granules in isotonic solutions of salts of strong acids such as K+CH3SO4- (methylsulfate), K+ CH2OHCH2SO3- (isethionate), and K2SO4 are stable between pH7.0 and 5.4. The granules behave as predicted for organelles with an acid interior and the data provide further evidence that the intragranular pH is acidic. In addition, the results strongly suggest that enkephalin-like material is stored together with catecholamine and ATP in an acid compartment.

Acetates↗
PubMed1977

Preparation of uniform haemoglobin free human erythrocyte ghosts in isotonic solution.

A method is described for the preparation of haemoglobin free human erythrocyte ghosts in isotonic solutions using dielectric breakdown technique. In this single haemolytic procedure, almost complete removal of haemoglobin (less than or equal to 0.1%) was achieved by subjecting the erythrocytes suspended in phosphate buffered, isotonic KCl solution at 0 degrees C to three consecutive electrical field pulses of 16 kV/cm in the presence of 10 mM EDTA; EDTA was used to prevent electrical haemolysis. Haemolysis is induced by subsequent dilution with isotonic and isoionic solution to lower the EDTA concentration. Haemolysis is complete after 5 min; the cells are centrifuged, washed and resuspended in a solution of the same composition and osmolarity containing 4 mM MgCl2, but no EDTA. The resealing process, carried out at 37 degrees C, was complete in about 1 h. Measurements of the size distribution of the ghost cells in the hydrodynamically focusing Coulter Counter at varying field strengths in the orifice revealed that the ghost population is nearly uniform. The mean (modal) volume of the ghost cells was 110--120 micronm3 when suspended in phosphate buffered NaCl solution. The apparent breakdown voltage was about 1.3 V.

Erythrocyte Membrane↗
PubMed2004

Proabsorptive effect of gum arabic in isotonic solutions orally administered to rats: effect on zinc and other solutes.

We have previously shown that the addition of gum arabic (GA) to oral rehydration solution (ORS) enhances water and electrolyte absorption during jejunal perfusion in rats under anesthesia. This study investigates whether GA by oral administration could be equally effective in rats. Isotonic solutions containing 25 g/L GA (AG), or without GA (A0) were administered via oral tube to lightly anesthetized adult female rats. Similar experiments were conducted with hypertonic solutions containing no GA (B0), or either 10 (B10) or 50 g/L GA (B50). Blood concentrations of sodium, glucose, glutamate, zinc, and tritiated water were determined at 0, 15, 30, 60, 90, 120, and 180 minutes, and results between treatments were compared. Administration of the isotonic, GA-containing solution (AG) resulted in a higher blood zinc level than with the isotonic GA-free solution (A0) from 15 minutes throughout 180 minutes. Blood zinc at 15 minutes (means +/- SEM) was as follows: for A0: 69.3 +/- 2.0, for AG: 83.4 +/- 3.5 nmol/L, P=0.002. At 180 minutes, A0: 52.6 +/- 1.8; AG: 68.1 +/- 4.6 nmol/L, P=0.004. The corresponding areas under the curve (AUC) were as follows: for A0: 10,737 +/- 214; for AG: 13,919 +/- 765 nmol x min/L, P<0.001). Glucose, glutamate, sodium, and tritiated water body distribution presented no differences in blood concentrations. For sodium and tritiated water body distribution, there was a significant time effect (P<0.0001). In hypertonic solutions, blood zinc levels declined over time, possibly due to their osmotic, counter-absorptive action, thus obscuring possible opposite effects of GA. GA appears to be an effective enhancer of zinc absorption when orally administered in isotonic solutions to laboratory animals. This proabsorptive capacity could be attributed to some of the physicochemical and biochemical properties of GA and suggest possible applications of GA in liquid formulas and solid food preparations.

Absorption↗
PubMed2005

Effects of ouabain on contractions induced by manganese ions in C2+a-free, isotonic solutions with varying concentrations of K+ in guinea-pig taenia coli.

The action of ouabain, a cell membrane Na+, K+-ATPase blocker, on contractions induced by manganese ions (Mn2+) in Ca2+-free, isotonic solutions with varying concentrations of K+ in the external medium were investigated in order to evaluate the underlying role of external Na+ in Mn2+-induced contractions in isolated taenia coli of the guinea-pig. Mn2+ at 5 mM induced greater contractions as external isotonic K+ concentrations progressively increased from 10 to 100 mM. Ouabain (2 x 10(-4) M) completely inhibited tension development stimulated by 5 mM Mn2+ in isotonic, 30 mM K+ (96 mM Na+) medium. Whereas, the tension inhibitory effects of ouabain became progressively weaker as isotonic, external K+ concentrations increased to 60 mM, which successively decreased external Na+ concentrations. Eventually, ouabain failed to affect contractions stimulated by Mn2+ in isotonic, 126 mM K+, Na+-deficient medium. Ouabain caused progressively greater increase in cellular Na+ concentrations as the Na+ concentrations increased in the isotonic, K+ medium. While, pyruvate, which penetrates cell independently of external Na+, reversed the inhibition of tension by ouabain in isotonic, 30 mM K+, Na+-sufficient (96 mM) medium containing 5 mM Mn2+. These results suggested that Mn2+ induced the contraction, which was maintained by glucose transport depending on external Na+, in the case of Na+-sufficient medium in K+-depolarized taenia coli. However, it induced the contraction independent of external Na+, in the case of Na+-deficient, K+ medium. Ouabain might exhibit greater inhibition of the contraction induced by Mn2+ as the decrease in the Na+ gradient across the cell membranes continues.

Animals↗
PubMed2004

Proabsorptive action of gum arabic in isotonic solutions orally administered to rats. II. Effects on solutes under normal and secretory conditions.

Gum arabic (GA) is a natural proteoglycan with proabsorptive capacity attributable to its physico-chemical properties. Previous experiments showed that in rats oral administration of GA in an isotonic solution had a generally positive effect. This study extends the investigation to include acetaminophen and to evaluate whether GA could also act under secretory conditions induced by theophylline. Test solutions were orally administered to rats under CO2 anesthesia and blood concentrations followed for 3 hr. The secretory effects of theophylline were clearly observed for sodium and zinc. Addition of GA resulted in a more rapid rate of glutamate absorption, under normal physiologic conditions, as indicated by the higher area under the curve (AUC). There were no differences in the presence of theophylline. Acetaminophen blood concentrations peaked about 30 min after administration, and the AUC in rats that received GA was higher than in those that got the solution without GA. AUCs for total body water distribution with time and those for glucose concentrations were indistinguishable whether the solutions contained or did not contain either GA or theophylline. The results confirm that oral administration of GA can accelerate absorption of some solutes, including pharmacologic agents.

Acetaminophen↗
PubMedDate not supplied

Multidetector CT of the small bowel: evaluation after oral hyperhydration with isotonic solution.

PURPOSE: The aim of our study was to assess the diagnostic capabilities of multidetector CT in the evaluation of the small bowel in different pathological conditions, with the use of oral hyperhydration with isotonic solution. MATERIALS AND METHODS: The study retrospectively evaluated 106 patients who underwent multidetector CT of the small bowel. Four groups were considered on the basis of the clinical findings: group A (48 cases), with suspected or certain chronic inflammatory disease of the small bowel; group B (16 cases), with suspected neoplastic lesion of the small bowel; group C (17 cases), patients affected by malabsorption; group D (25 cases), others: 13 cases with non-specific abdominal pain, 4 cases with occult bleeding, 8 cases affected by fever of unknown origin. Thirteen patients had previously undergone surgical intestinal resection. In all cases the CT examination was performed after the oral administration of 2000 mL polyethylene glycol electrolyte balanced solution; before the scan, N-butyl scopolamine or glucagon were administered intravenously to obtain rapid inhibition of bowel peristalsis. All multidetector CT scans were acquired at baseline and 50 seconds after the I.V. administration of 110-130 ml high-concentration non-ionic iodinated contrast medium. The images were subsequently processed on a dedicated workstation (Advantage Windows 4.0, GE Medical Systems) to obtain multiplanar reconstruction (MPR). We considered the following CT findings: fold distribution, wall thickening and stratification and contrast enhancement, extraparietal involvement and abnormalities of the abdominal organs. The CT diagnoses were compared with the clinical and laboratory findings (86 cases) and with the results of barium follow-through (55 cases), ileo-colonoscopy (45 cases) or surgery (28 cases). RESULTS: CT examination allowed the correct diagnosis in 86/106 cases (89%); 20 patients were not included in the study because of a poor (11 cases) or absent (9 cases) small bowel loop distension. The final diagnoses in the 86 patients were: Crohn's disease of the small bowel (38 cases), Crohn's disease of the duodenum (1 case), granulomatous colitis (3 cases), malabsorption (8 cases), neoplastic lesion (4 cases), post-radiation conglomeration of ileal loops (1 case), intestinal lymphangiectasia (1 case), ulceration of the last ileal loop (1 case). In 29 cases no abnormalities of the small bowel were found. Spiral CT yielded 52 true positive cases, 5 false negative cases, 2 false positive cases, and 27 true negative RESULTS: The sensitivity of the technique was 91%, specificity 93% and diagnostic accuracy 92%. CONCLUSIONS: Multidetector CT of the small bowel performed after oral hyperhydration with isosmotic solution, proved to be an accurate and thorough technique. It can be considered a safe and effective alternative to conventional radiographic studies and to small bowel spiral CT enema in patients that refuse the nasojejunal balloon catheter or the administration of methylcellulose.

Journal Article↗