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PubMed2002

[Effect of the pretreatment with organic acid buffer solutions on the recovery of Legionella species from environmental water samples].

Anti-microbial effect of the pretreatment with various organic acid buffer solutions against co-existing microorganisms which were isolated from cooling-tower water samples along with Legionella spp. was examined. Among several buffer solutions, a 0.1 M potassium citrate-citric acid buffer solution (hereafter, citrate buffer solution, pH 2.2) hardly affected the recovery of Legionella spp., but effectively inhibited the growth of co-existing microorganisms. To evaluate the buffer action of these buffer solutions, pHs of 9 cooling-tower water samples were evaluated after addition of an equal volume of each buffer solution. When a citrate buffer solution. pH 2.2 was combined to a 200-fold concentrated solution of each cooling-tower water sample, the pH of the combined solution became 2.5 to 2.7 and maintained a stably low pH value than that (pH 3.0 to 7.4) obtained after mixture of a 0.2 M HCl-KCl buffer solution (hereafter, HCl buffer solution, pH 2.2), suggesting strong buffer action of the citrate buffer solution, pH 2.2 in the combined solutions. Furthermore, when cooling-tower water samples were pretreated with a citrate buffer solution, pH 2.2, the recovery of Legionella spp. was successful in 7 out of 9 cooling-tower water samples, suggesting 3 times higher recovery rate than that obtained by addition of a HCl buffer solution, pH 2.2 (3 out of 9 cooling-tower water samples).

Acids↗
PubMed1988

Improved myocardial protection by oxygenation of St. Thomas' Hospital cardioplegic solutions. Studies in the rat.

The effect of oxygenation (100% oxygen) of the St. Thomas' Hospital cardioplegic solutions No. 1 (MacCarthy) and No.2 (Plegisol, Abbott Laboratories, North Chicago, Ill.) was examined in the isolated working rat heart subjected to long periods (3 hours for studies with solution No. 1 and 4 hours for studies with solution No. 2) of hypothermic (20 degrees C) ischemic arrest with multidose (every 30 minutes) cardioplegic infusion. At the aortic infusion point the oxygen tension of the oxygenated solutions (measured at 20 degrees C) was in the range of 320 to 560 mm Hg whereas that of the nonoxygenated solutions was less than 150 mm Hg. Twenty hearts (10 oxygenated and 10 nonoxygenated) were studied for each solution. The studies with solution No. 1 demonstrated that oxygenation led to a significant (p less than 0.05) reduction in the incidence of persistent ventricular fibrillation during postischemic reperfusion. Oxygenation of the cardioplegic solution also improved postischemic functional recovery so that the recovery of aortic flow was improved from 18.7% +/- 8.9% (of its preischemic control level) in the nonoxygenated group to 54.6% +/- 6.6% in the oxygenated group (p less than 0.025). Creatine kinase leakage was also significantly reduced from 27.5 +/- 4.8 to 9.9 +/- 0.6 IU/15 min/gm dry weight (p less than 0.005). Studies with solution No. 2 indicated that protection was better than with solution No. 1, even in the absence of oxygenation. A better degree of functional recovery was obtained after 4 hours of arrest with solution No. 2 than that obtained after only 3 hours of arrest with solution No. 1, and persistent ventricular ventricular fibrillation was never observed with solution No. 2. However, despite the superior performance with solution No. 2, further improvements could be obtained by oxygenation, with that time from the onset of reperfusion to the return of regular sinus rhythm being reduced from 55 +/- 8 to 35 +/- 2 seconds (p less than 0.01), postischemic recovery of aortic flow increasing from 59.8% +/- 7.4% to 85.7% +/- 2.5% (p less than 0.005), and creatine kinase leakage being reduced from 38.1 +/- 7.3 to 16.2 +/- 1.5 IU/15 min/gm dry weight (p less than 0.005). It is concluded that oxygenation of the St. Thomas' Hospital cardioplegic solutions improves their ability to protect the heart against long periods of ischemia and that this is manifested by improved postischemic electrical stability, functional recovery, and reduced creatine kinase leakage.

Animals↗
PubMed1996

Effective 30-hour preservation of canine lungs with modified ET-Kyoto solution.

BACKGROUND: With the aim of developing a preservation solution that can preserve donor lungs reliably for a long time, we prepared a modified ET-Kyoto solution by adding N-acetylcysteine, nitroglycerin, and dibutyryl adenosine 3', 5'-cyclic phosphate to the previously reported ET-Kyoto solution, which contains trehalose, gluconate, and hydroxyethyl starch. In this study, we examined the efficacy of modified ET-Kyoto solution in 30-hour lung preservation. METHODS: Twenty five pairs of adult mongrel dogs were divided into four groups. Donor lungs were flushed with modified ET-Kyoto solution (n = 9), with ET-Kyoto solution (n = 6), with University of Wisconsin solution group (n = 6), or with ET-Kyoto solution plus the solvents of nitroglycerin (ethanol and propylene glycol) (n = 4), then stored at 4 degrees C for 30 hours. All animals were treated with prostaglandin E1. Left lungs were transplanted and reperfused for 6 hours. RESULTS: With respect to arterial oxygen tension, peak inspiratory pressure, and wet-to-dry lung weight ratio, modified ET-Kyoto solution was significantly superior to ET-Kyoto solution. The modified ET-Kyoto solution was significantly superior to University of Wisconsin solution with respect to survival rate, arterial oxygen tension, and wet-to-dry lung weight ratio. Ultrastructural findings supported these results. CONCLUSIONS: These results suggest that modified ET-Kyoto solution is superior to University of Wisconsin solution for 30-hour lung preservation.

Acetylcysteine↗
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↗
PubMedDate not supplied

Effects of calcium concentration, lactobionate content, and sodium/ potassium ratio of preservation solutions on resting left ventricular pressure and postreperfusion function of rabbit heterotopic heart transplants.

BACKGROUND: We tested the hypothesis that the University of Wisconsin solution has a ionic composition (i.e., intracellular, calcium-free, lactobionate-enriched) that may be beneficial for cold heart graft preservation independently from any additives. METHODS: St. Thomas' Hospital and University of Wisconsin solutions were compared with the following: (1) C solution, a simplified University of Wisconsin-like solution (i.e., intracellular, calcium-free, lactobionate-enriched); (2) A solution, an St. Thomas' Hospital-like solution (extracellular, calcium [Ca2+] = 1.2 mmol/L) in which chloride was replaced by lactobionate; (3) B solution, an intracellular, lactobionate-enriched, calcium-containing solution ([Ca2+] = 1.2 mmol/L). Rabbit hearts were transplanted heterotopically in the abdomen of recipient animals either immediately or after 6 hours of storage. Hemodynamic parameters were recorded 60 minutes after unclamping. RESULTS: After a 6-hour storage, University of Wisconsin and C solutions provided better preservation than B and St. Thomas' Hospital solutions: diastolic pressures were lower; developed pressure and rate of pressure rise were higher. C solution was superior to University of Wisconsin solution only for rate of pressure rise. A solution was intermediary. A significant alteration of resting pressure and hemodynamic parameters was generally observed during the 6-hour storage. Nonsignificant changes of developed pressure and rate of pressure rise were only observed in C and B solutions: This is explained by systolic alteration after immediate reimplantation for the B group and good preservation for the C group. Resting pressure was unchanged over a 6-hour storage only for the C group, but this measure was not determined for University of Wisconsin. A correlation exists for various left ventricular volumes between resting pressure and postreperfusion hemodynamic data. Replacement of chloride by lactobionate (A versus St. Thomas' Hospital) may have improved resting and diastolic pressures by other mechanisms than limitation of net water gain during storage.

Adenosine↗
PubMed1997

[Intestinal lavage solution for orthograde intestinal irrigation].

Gut lavage by ingestion of large volumes of electrolyte solutions has been shown to be an effective method of cleansing the colon before colonoscopy, barium enema or surgery. Absorption of water and electrolytes, which might be hazardous to patients who are unable to readily excrete an additional sodium and/or water load, is prevented by addition of non-absorbable substances to the solutions, but systematic studies are lacking. We have evaluated the influence of three solutions for gut lavage with different electrolyte composition (sodium concentration 67 mmol/l and 125 mmol/l) and addition of different non-absorbable substances (mannitol and polyethylene glycol [PEG]) on water and electrolyte homeostasis and subjective tolerance, both in healthy volunteers and in patients before endoscopy of the colon. In a randomized, blind study 6 liters of the three solutions were administered via a nasogastric tube to 6 healthy volunteers during 4 hours (i.e. 1.5 l/h). Body weight, serum concentrations of sodium, potassium and of phosphate were measured before infusion of the solution and after the last rhythmic rectal effluent. No significant changes were observed in any of the studied parameters and the incidence of side effects (nausea, abdominal cramps) was comparable. In an additional clinical double blind study, 26 patients before diagnostic colonoscopy were asked to drink 4 liters of the gut lavage solutions as quickly as possible in order to clean out the colon. The time for drinking was significantly shorter in patients using the mannitol and low sodium solution (204 +/- 70 minutes) than in patients drinking the solution with polyethylene glycol and a high sodium concentration (387 +/- 137 minutes). There was a tendency to a longer drinking period in patients ingesting the solution with polyethylene glycol and low sodium (306 +/- 106 minutes). Thus, the acceptance for solutions containing polyethylenglycol and high sodium concentration is reduced because of low palatibility. Again no influence on serum electrolyte concentrations or body weight could be observed in any patient, the spectrum of side effects was similar and the cleansing effect of all three solutions was adequate. In conclusion solutions for gut lavage containing a balanced electrolyte concentration and nonresorbable substances such as mannitol or polythylenglycol are equivalent. However, solutions containing mannitol and a low sodium concentration are better tolerated by the patients but the use of mannitol is limited because of the risk of releasing explosive gases during interventional endoscopy. To enhance the acceptance and palatibility of solutions for gut lavage containing polethylenglycol the addition of flavoured substances is recommended.

Adult↗
PubMed1992

Superiority of the University of Wisconsin solution over simple crystalloid for extended heart preservation. A study of left ventricular pressure-volume relationship.

To compare the effects of the University of Wisconsin solution with those of an extracellular crystalloid solution, Krebs-Ringer bicarbonate, as cardiac preservation media, we studied 35 adult dogs in an isolated heart preparation. Four groups of seven hearts were preserved in University of Wisconsin solution for 6 or 12 hours or in Krebs-Ringer bicarbonate solution for 6 or 12 hours. An additional group of seven hearts with no ischemia was used for a control group. In the four preservation groups, hearts were arrested by electrolyte solution (Normosol with potassium chloride, 20 mEq/L, added, 4 degrees C), flushed with 200 ml of the preservation solution, and then stored in the same solution at 1 degree to 2 degrees C. The hearts were mounted on an isolated heart preparation equipped with a computer-controlled servo-pump system that used a mock arterial system to modulate the aortic input impedance presented to the left ventricle. Left ventricular pressure-volume loops were measured on-line for 2 hours of reperfusion with autologous warm oxygenated blood. Elastance was derived from the end-systolic pressure-volume relationship, and diastolic compliance was derived from the end-diastolic pressure-volume relationship. The total left ventricular performance was assessed by the preload recruitable stroke work area, the slope, and its x-intercept, all of which derived from the stroke work (pressure-volume area)-end-diastolic volume relationship. Extended global ischemia had more deleterious effects on the end-diastolic than the end-systolic pressure-volume relationship. In confirmation with other studies, elastance did not accurately reflect the level of ventricular contractile dysfunction because of the significant amount of diastolic dysfunction. The preservation of myocardial systolic and diastolic functions, as demonstrated by the preload recruitable stroke work area and diastolic compliance, was better in the University of Wisconsin solution groups than in the Krebs-Ringer bicarbonate solution groups after 6 and 12 hours of preservation. In addition, 6 hours of preservation with University of Wisconsin solution maintained normal systolic and diastolic functions as compared with those of the control group. Preservation with University of Wisconsin solution prevented any myocardial edema formation; by contrast, this was significantly increased after 12 hours in Krebs-Ringer bicarbonate solution. Groups preserved with University of Wisconsin solution had less reperfusion injury as evidenced by the release of coronary sinus creatine kinase during reperfusion; they also had improved oxygen use during reperfusion.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenosine↗
PubMed2005

Application of ultrasonic shear rheometer to characterize rheological properties of high protein concentration solutions at microliter volume.

The purpose of this work was to conduct preliminary rheological analysis on high protein concentration solutions by using the technique of ultrasonic shear rheometry at megahertz frequencies. The work was aimed at establishing the viability of the technique for analyzing protein solution rheology as well as obtaining an initial understanding of the effect of solution conditions on solution rheology of a model protein. Bovine serum albumin (BSA) was used for this study, and rheological analysis was conducted at 20 microL sample volume between pH 2.0 and 9.0 at different ionic strengths at 25 degrees C using 5 and 10 MHz quartz crystals. Significant differences in storage modulus among solutions at pH 5.0, 7.0, and 9.0 could only be detected at 10 MHz, and the errors associated with measurements were smaller as compared to those at 5 MHz for all the solutions studied. Solutions at pH 2.0 and 3.0 showed a time-dependent change in solution rheology. For solutions at pH 5.0, 7.0, and 9.0, which did not show time dependence in solution rheology, loss modulus data at lower concentrations correlated well with the dilute solution data in the literature. At higher concentrations, pH 5.0 solutions exhibited a higher loss modulus than pH 7.0 and pH 9.0 solutions. Storage modulus decreased with increasing ionic strength, unlike loss modulus, which did not show any change, except at pI of protein when no effect was observed. The results show the potential of high frequency rheometry for analyzing subtle differences in rheology of pharmaceutically relevant protein solutions at microliter volume.

Hydrogen-Ion Concentration↗
PubMed1992

Prolonged rat pancreas preservation using a solution with the combination of histidine and lactobionate.

A newly formulated solution consisting of lactobionate with or without histidine was tested in the preservation of the rat pancreas. Adult male Lewis rats weighing 120-250 g were used as donors and recipients. Fifty-four rat pancreas transplants were performed to investigate the effectiveness of this test solution and to compare it with the standard University of Wisconsin (UW) solution. The final osmolarity of the new test solution was 290-320 mosmol/l. This solution had a higher sodium content and lower potassium content (Na: 110 mEq/l, K: 50 mEq/l). Adenosine, insulin, hydroxyethyl starch and dexamethasone, which are components of the UW solution, were not present in this test solution. Histidine was used as a buffer. Rat pancreases were stored at 4 degrees C in either standard UW solution, or high-Na+-histidine solution, or high-Na+-lactobionate solution for 48 h and 72 h prior to heterotopic transplantation into rats with streptozotocin-induced diabetes mellitus. Functional success rates for rats receiving pancreases that had been preserved in high-Na+-histidine and in high-Na+-lactobionate solutions at 4 degrees C were 100% (5/5) and 100% (7/7) after 48 h preservation, and 50% (4/8) and 14% (1/7) after 72 h preservation, respectively. By contrast, standard UW solution gave only a 44% (4/9) success rate after 48 h preservation and a 0% (0/8) success rate after 72 h preservation. These results demonstrated that the high-Na+-histidine solution was superior to standard UW solution for rat pancreas preservation. This was probably due to the buffer, histidine, which prevented the acidosis of ischemic tissue during the period of preservation.

Animals↗
PubMed2004

Analytical solutions for reactive transport under an infiltration-redistribution cycle.

Transport of reactive solute in unsaturated soils under an infiltration-redistribution cycle is investigated. The study is based on the model of vertical flow and transport in the unsaturated zone proposed by Indelman et al. [J. Contam. Hydrol. 32 (1998) 77], and generalizes it by accounting for linear nonequilibrium kinetics. An exact analytical solution is derived for an irreversible desorption reaction. The transport of solute obeying linear kinetics is modeled by assuming equilibrium during the redistribution stage. The model which accounts for nonequilibrium during the infiltration and assumes equilibrium at the redistribution stage is termed partial equilibrium infiltration-redistribution model (PEIRM). It allows to derive approximate closed form solutions for transport in one-dimensional homogeneous soils. These solutions are further applied to computing the field-scale concentration by adopting the Dagan and Bresler [Soil Sci. Soc. Am. J. 43 (1979) 461] column model. The effect of soil heterogeneity on the solute spread is investigated by modeling the hydraulic saturated conductivity as a random function of horizontal coordinates. The quality of the PEIRM is illustrated by calculating the critical values of the Damköhler number which provide the achievable accuracy in estimating the solute mass in the mobile phase. The distinguishing feature of transport during the infiltration-redistribution cycle as compared to that of infiltration only is the finite depth of solute penetration. For irreversible desorption, the maximum solute penetration W/theta(r) is determined by the amount of applied water W and the residual water content theta(r). For sorption-desorption kinetics, the maximum depth of penetration z(r)(e, infinity ) also depends on the ratio between the rate of application and the column-saturated conductivity. It is shown that z(r)(e, infinity ) is bounded between the depths W/(theta(r)+K(d)) and W/theta(r) corresponding to the maximum solute penetration for equilibrium transport and for irreversible desorption, respectively. This feature of solute penetration explains the unusual phenomena of plume contraction after an initial period of spreading [Lessoff, S.C., Indelman, P., Dagan, G., 2002. Solute transport in infiltration-redistribution cycles in heterogeneous soils. In Raats, P.A.C., Smiles, D.,Warrick, A.W. (Eds), Environmental Mechanics: Water, Mass and Energy Transport in the Biosphere. American Geophysical Union, pp. 133-144]. Unlike transport under equilibrium conditions, when the solute is completely concentrated at the front, the solute under nonequilibrium conditions is spread out behind the front. Heterogeneity leads to additional spreading of the plume.

Adsorption↗
PubMed2006

Characterization of aggregate structure in mercerized cellulose/LiCl.DMAc solution using light scattering and rheological measurements.

The structure of a semidilute solution of mercerized cellulose (CC1m) in 8% (w/w) LiCl.DMAc, which contained some aggregates, was investigated using static and dynamic light scattering measurements. The static scattering function of the polymer solution containing a small amount of aggregates can be separated into fast- and slow-mode components by combining static and dynamic light scattering measurements. The osmotic modulus was identical for the fast-mode component of the CC1m solutions and the native cellulose (CC1) solutions, in which cellulose is dispersed molecularly. This indicates that the molecularly dispersed component of the CC1m solutions has an identical conformation with the cellulose molecules in the CC1 solutions. The correlation length was also identical for the fast-mode components of CC1m solutions and the CC1 solutions, indicating that these solutions have the same mesh size of the polymer entanglement. These observations for the fast-mode components are consistent with the concentration dependence of the zero shear rate viscosity and the plateau modulus estimated in the rheological measurements. The slow-mode component, on the other hand, gave information on the aggregate structure in the CC1m solution. The radius of gyration of the aggregate structure estimated from the slow-mode component was about 70 nm, which is independent of the concentration of the solution. The plots for particle scattering factor of the slow-mode component lay between the theoretical curve of a sphere and a Gaussian chain, implying that the structure of the aggregate in the CC1m solution is like a multiarm polymer. A characteristic time of the slow-mode component calculated with the translational diffusion coefficient and the radius of gyration were almost identical with the relaxation time of the long-time relaxation observed in the rheological measurements. This indicates that the long-time relaxation of CC1m solutions originates in the translational diffusion of the aggregate structure in the solution.

Acetamides↗
PubMed1996

Effects of sugars and polymers on crystallization of poly(ethylene glycol) in frozen solutions: phase separation between incompatible polymers.

PURPOSE: This study examined the effect of third components (low-molecular-weight saccharides and polymers) on the crystallization of poly(ethylene) glycol (PEG) in frozen solutions, focusing on the relationship between their crystallization-inhibiting ability and molecular compatibility. METHODS: Effects of sugars and polymers on the crystallization of PEG 3000 in frozen solution were monitored by differential scanning calorimetry (DSC). Pulsed-NMR was employed to monitor the molecular mobility of water and solutes in the frozen solutions. Miscibility between PEG and third components in aqueous solution was estimated from the lowering of cloud point of PEG 20,000. Thermal analysis of frozen solutions containing some non-crystallizing solutes was used to examine the possibility of phase separation in frozen solutions. RESULTS: Some sugars and polymers inhibited the crystallization of PEG and formed practically stable amorphous phases among ice crystals. The mobility of solute molecules in the amorphous phase increased above the softening temperature of maximally concentrated solutions (Ts), whereas that of water molecules appeared at a lower temperature. Mono- and disaccharides that are relatively less miscible with PEG in solution inhibit PEG crystallization to a lesser degree. Two Ts regions were observed in frozen solutions containing both polyvinylpyrrolidone (PVP) and dextran, at much lower concentrations than those causing aqueous two-phase separation at ambient temperatures. CONCLUSIONS: Ice crystallization raises the concentration of solutes in the remaining solution, which can lead to phase separation in the amorphous phase. Molecular compatibility between components is an important factor determining their propensity to phase separate and crystallize.

Calorimetry, Differential Scanning↗
PubMed2003

Clinical experience with two physiologic bicarbonate/lactate peritoneal dialysis solutions in automated peritoneal dialysis.

UNLABELLED: Clinical experience with two physiologic bicarbonate/lactate peritoneal dialysis solutions in automated peritoneal dialysis. BACKGROUND: Patients on automated peritoneal dialysis (APD) usually receive larger volumes of dialysis solution and more frequent, shorter exchanges than patients on continuous ambulatory peritoneal dialysis (CAPD), and therefore are likely to derive greater benefit from more physiologic solutions. METHODS: Peritoneal dialysis solutions containing 25 mmol/L bicarbonate and either 10 or 15 mmol/L lactate were compared with standard lactate solutions (35 or 40 mmol/L) in two prospective, open-label studies of patients on APD. Each study included a 2-week baseline period (lactate solution), a 6-week treatment period (bicarbonate/lactate solution), and a 2-week follow-up period (same lactate solution as baseline). Biochemical analyses and assessments of vital signs and safety parameters were conducted at baseline, every 2 weeks during treatment, and at the end of the follow-up period. A product use questionnaire was administered in one study at the end of treatment. RESULTS: A statistically significant rise in plasma bicarbonate (approximately 2 mmol/L) occurred when patients switched from a lactate solution to the bicarbonate/lactate solution with equimolar buffer concentration (P < 0.001 for each solution). Plasma bicarbonate decreased by 1.16 mmol/L after a switch from lactate 40 mmol/L to bicarbonate/lactate 35 mmol/L (P < 0.001). When patients switched to bicarbonate/lactate 35, the majority of individual venous plasma bicarbonate values were in the normal range. A switch from a lower calcium (1.25 mmol/ L) lactate solution to a higher calcium (1.75 mmol/L) lactate/bicarbonate solution resulted in a statistically significant rise in serum calcium (0.06 mmol/L, P < 0.018). The product use questionnaire revealed improvements in symptoms, including reduced pain on infusion. CONCLUSION: Bicarbonate/lactate solutions may be used safely and effectively in patients on APD. The availability of 2 formulations with different buffer and calcium content provides flexibility for the control of acidosis as well as calcium balance.

Automation↗
PubMed1991

Rice-based oral electrolyte solutions for the management of infantile diarrhea.

BACKGROUND: In infants the treatment of acute diarrhea with glucose-based solutions results in rehydration but does not reduce the severity of diarrhea. Oral rehydration with solutions based on rice powder may reduce stool output as well as restore fluid volume. METHODS: We designed a prospective, randomized, double-blind study to evaluate the efficacy of two rice-based rehydration solutions and a conventional glucose-based solution. Solution A contained only rice-syrup solids, solution B contained rice-syrup solids and casein hydrolysate, and solution C, the glucose-based solution, served as control. The study subjects were 86 mildly to moderately dehydrated infant boys, 3 to 18 months old, who were admitted to a children's hospital with acute diarrhea. We measured fluid intake, fecal and urine output, and absorption and retention of fluid, sodium, and potassium at intervals for 48 hours in all 86 infants. RESULTS: The mean (+/- SE) fecal output was significantly lower in the infants given solution A (group A infants) than in the infants given solution C (group C) (29 +/- 4 vs. 46 +/- 7 ml per kilogram of body weight, P less than 0.05) during the first six hours of therapy. The infants in group A also had greater fluid absorption (221 +/- 16 vs. 167 +/- 9 ml per kilogram, P less than 0.05) over the entire 48 hours of therapy and greater potassium absorption (1.6 +/- 0.2 vs. 0.6 +/- 0.1 mmol per kilogram, P less than 0.05) during the first six hours than the infants in group C. Solution B offered no advantages over solution A. CONCLUSIONS: Solutions containing rice-syrup solids were effective in the rehydration of infants with acute diarrhea. They decreased stool output and promoted greater absorption and retention of fluid and electrolytes than did a glucose-based solution.

Acute Disease↗
PubMed1994

The effects of daily wear of rigid gas permeable contact lenses treated with contact lens care solutions containing preservatives on the rabbit cornea.

We evaluated the effects on the rabbit cornea of daily wear of rigid gas permeable (RGP) contact lenses treated with preserved care solutions by measuring concomitant tear lactate dehydrogenase (LDH) activity followed by in vivo tandem scanning confocal microscopy (TSCM). In vivo morphologic changes were confirmed by in vitro scanning electron microscopy (SEM). Two standard commercial RGP lens wetting and soaking solutions from the same manufacturer were tested: solution A with 0.004% benzalkonium chloride (BAK) and solution B with 0.003% chlorhexidine digluconate (CHX) and 0.002% thimerosal. Two experimental PBS-based wetting and soaking solutions were also tested: solution C with 0.005% BAK and 2% hydroxypropylmethylcellulose (HPMC) and solution D with 0.005% BAK without HPMC. Instillation of solution A without contact lens wear caused significant (P < 0.01) increases in desquamation of the superficial corneal epithelium and tear LDH activity compared with control eyes. After 3 weeks of RGP contact lens daily wear (8 hours/day), modified Draize scores of ocular surface lesions on the eyes wearing RGP lenses treated with solution A increased according to the duration of lens wear. Solution B did not produce significant change. With daily wear for 4 days (8 hours/day), RGP lenses treated with solution C and solution D produced increased corneal epithelium desquamation and an increase of LDH activity in tears. These effects were greater with HPMC (solution C) than without HPMC (solution D).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2006

Disinfecting solutions for soft contact lenses using different color indicators.

PURPOSE: The color change reached in two commercial disinfecting solutions for soft contact lenses using new color indicators has been analyzed, and its relationship with the temporal evolution of the hydrogen peroxide concentration, responsible for the disinfection process, has been examined. The results are compared with another commercial solution using a different color indicator. METHODS: Color measurements of the disinfecting solutions were performed at 2-minute intervals for over 2 hours using a Photo-Research PR-704 spectroradiometer with horizontal optical axis. Samples were placed at the floor of a VeriVide CAC 120 light booth with a Munsell gray mask behind them. Two different standard light sources, representative of outdoor and indoor illumination, were used. The hydrogen peroxide concentration during the disinfection process was measured for each commercial solution using a Beckman DU-7 spectrophotometer. RESULTS: The temporal evolutions of color for the two new disinfecting solutions were qualitatively different. CIELAB color differences induced in these two new disinfecting solutions were 1.5 and 2.2 times greater than that measured in the earlier comparative solution and occur in a more appropriate direction of color space for users with defective color vision. Although the earlier solution generated color changes close to the deutan confusion line, the changes produced by the new solutions are close to the tritan confusion line. After 2 hours, the hydrogen peroxide concentration for the two new solutions was approximately one-third the one reached by the earlier solution. There are statistically significant correlations (p < 0.01) between color change and hydrogen peroxide concentration for the two new solutions (r = -0.878 and r = -0.990). CONCLUSIONS: Color changes in these hydrogen peroxide systems can be used as a safe and useful tool by contact lens wearers. The two new disinfecting solutions analyzed in this article show noteworthy improvements over the earlier solution.

Color↗
PubMed2002

Comparison of contact lens multipurpose solutions by in vitro sodium fluorescein permeability assay.

PURPOSE: This article reports the use of in vitro sodium fluorescein permeability assay to study the effects of various contact lens disinfecting solutions on the integrity of epithelium. METHODS: We compared the sodium fluorescein permeability of monolayer cultures of Madin-Darby canine kidney cells (MDCK) after exposure to ReNu Multi-Purpose Solution, ReNu MultiPlus Multi-Purpose Solution, OPTIFREE Express Multi-Purpose Solution, OPTIFREE Express Solution with Aldox, SOLO-care Solution and Complete Comfort Plus Solution. Additional cell monolayer inserts were prepared for each treatment and were analyzed using a scanning electron microscope. The assay has been used to measure the potential for ocular irritancy of a test solution by evaluating its effect on the cell membranes and tight junctions of a cultured canine kidney epithelial cell monolayer. RESULTS: The sodium fluorescein permeability assay and scanning electron microscopy demonstrated that the two OPTIFREE Express solutions were significantly more damaging to the MDCK epithelium than ReNu and ReNu MultiPlus multipurpose solutions (Bausch & Lomb, Rochester, NY), SOLO-care (CIBA Vision, Duluth, GA) solution, and Complete Comfort Plus (Allergan, Irvine, CA) solution. Cultures treated with the two OPTIFREE Express (Alcon, Ft. Worth, TX) solutions were more permeable to sodium fluorescein than cultures treated with the other multipurpose solutions, because of the loss of tight junctions and cell membrane damage. CONCLUSIONS: This experiment demonstrates that the sodium fluorescein permeability assay can be used to determine the effect that various contact lens disinfecting products have on the integrity of an epithelium in culture.

Animals↗
PubMed1985

Amino acid stability and microbial growth in total parenteral nutrient solutions.

The stability of amino acids in total parenteral nutrient (TPN) solutions stored for 30 days and the potential for stored TPN solutions to support growth of microbial contaminants were studied. Solutions of 3.5% crystalline amino acids and 25% dextrose with electrolytes were prepared either by using a commercially available amino acid solution with electrolytes or by adding electrolytes individually to a base TPN solution. Solutions were stored in polyvinyl chloride bags at refrigerated (4 degrees C) or room (25 degrees C) temperature for 30 days. Some bags were inoculated with Candida albicans or Pseudomonas maltophilia before storage to serve as positive controls for evaluation of microbial contamination. At appropriate intervals, bags of each type of solution under each storage condition were analyzed for amino acid content. Microbial growth was evaluated by filtering the contents of each bag and incubating the filter in brain-heart infusion broth. No microbial growth was detected in any of the study solutions, but all solutions inoculated with C. albicans and 2 of 16 solutions inoculated with Ps. maltophilia had evidence of growth. No significant decreases in the concentrations of any of the amino acids were noted for solutions stored at refrigerated temperature, but significant decreases in the concentrations of arginine and methionine were noted for solutions stored at room temperature. Total parenteral nutrient solutions can be stored for up to 30 days if they are kept at refrigerated temperatures and protected from light; however, quality assurance measures for these solutions should include end-product microbiologic testing.

Amino Acids↗