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PubMed1986

Theoretical derivation of solute-solvent interaction parameter in binary solution: case of the deviation from Raoult's law.

In a binary mixture, partial vapor pressure may show either a positive or negative deviation from the predicted value of an ideal solution. In this report we derive the deviation from Raoult's law from the heat of mixing, delta H mix, and the molal volume, V, of each of the components of a binary solution. This derivation is then tested for seven sets of combinations of two different solvents, taken at random from the literature. Each set consists of several different ratios of solute-solvent. The correlation between the reported experimental values of the partial vapor pressure of a given component, P1, and the theoretically derived values is excellent. The same derivation is further applied to calculate the solute-solvent interaction parameter, beta 12, independently from the geometric mean assumption of regular solution theory. In a number of cases, especially in hydrocarbon-alcohol mixtures, beta 12 proves to be significantly different from the calculated geometric mean square root beta 11 beta 22 or from the Walker interaction parameter term, K.

Chemical Phenomena↗
PubMed1991

Evaluation of a new calcium containing cardioplegic solution in the isolated rabbit heart in comparison to a calcium-free, low sodium solution.

Isolated perfused rabbit hearts were studied to compare the effects of 3 hour ischemic arrest following either calcium-free or calcium-containing cardioplegia, on the recovery of isovolumic function of the left ventricle, coronary flow, release of creatine phosphokinase and myocardial water content. The hearts perfused with the calcium-containing solution (Ca 0.5 mmol/L) showed better recovery of the developed pressure in the left ventricle, and its first derivative and compliance. Coronary flow at a constant perfusion pressure was better restored during reperfusion in the hearts with calcium-containing solution. The release of less CPK and a lower water content were also observed in the hearts reperfused with calcium-containing solution. We concluded that calcium-containing cardioplegic solution with a high concentration of magnesium (10 mmol/L) was superior to calcium-free solution for myocardial protection.

Animals↗
PubMed1987

Enzyme action in polymer and salt solutions. II. Activity of penicillin acylase in poly(ethylene glycol) and potassium phosphate solutions in relation to water activity.

Increasing concentrations of poly(ethylene glycol) and potassium phosphate solutions decreased the enzymatic activity of penicillin acylase (penicillin aminohydrolase, EC 3.5.1.11). Low molecular weight poly(ethylene glycol) reduced the penicillin acylase activity more than high molecular weight poly(ethylene glycol). The decrease in enzymatic activity seemed to be related to the decrease in water activity in solutions containing poly(ethylene glycol), irrespective of the molecular weight of the polymer. The decrease in enzymatic activity in potassium phosphate solutions was lower than in poly(ethylene glycol) solutions and did not fit the water activity relationship. The decreased enzymatic activity is discussed in relation to the enzyme stability in these solutions.

Amidohydrolases↗
PubMed1983

Thermodynamic nonideality and the dependence of partition coefficient upon solute concentration in exclusion chromatography. II. An improved theory of equilibrium partitioning of concentrated protein solutions. Application to hemoglobin.

An improved theory for the partitioning of protein between concentrated bulk solution and solution sequestered in a porous medium is presented. The theory is based upon the assumption that the sequestered solution may be formally represented as a sum of three compartments: (1) a compartment which Is inaccessible to protein, but accessible to solvent and small molecule solutes; (2) a surface layer immediately adjacent to the pore boundary, within which protein molecules are constrained to quasi-two-dimensional motion; and (3) the remaining volume accessible to protein, within which the protein molecules behave as if in bulk solution. The dependence of the partition coefficient of hemoglobin upon protein concentration over the range 10-225 g/l, calculated using the theory presented, is found to agree quantitatively with experimental data presented previously (R.J. Siezen, L.W. Nichol and D.J. Winzor, Biophys. Chem. 14 (1981) 221) without invoking self-association of hemoglobin molecules.

Animals↗
PubMed2006

Contribution of extracellular ice formation and the solution effects to the freezing injury of PC-3 cells suspended in NaCl solutions.

The mechanism of cell injury during slow freezing was examined using PC-3 human prostate adenocarcinoma cells suspended in NaCl solutions. The objective was to evaluate contribution of extracellular ice and the 'solution effects' to freezing injury separately. The solution effects that designate the influence of elevated concentration were evaluated from a pseudo-freezing experiment, where cells were subjected to the milieu that simulated a freeze-thaw process by changing the NaCl concentration and the temperature at the same time. The effect of extracellular ice formation on cell injury was then estimated from the difference in cell survival between the pseudo-freezing experiment and a corresponding freezing experiment. When cells were frozen to a relatively higher freezing temperature at -10 degrees C, about 30% of cells were damaged mostly due to extracellular ice formation, because the concentration increase without ice formation to 2.5-M NaCl, i.e., the equilibrium concentration at -10 degrees C, had no effect on cell survival. In contrast, in the case of the lower freezing temperature at -20 degrees C, about 90% of cells were injured by both effects, particularly 60-80% by the solution effects among them. The present results suggested that the solution effects become more crucial to cell damage during slow freezing at lower temperatures, while the effect of ice is limited to some extent.

Adenocarcinoma↗
PubMed1998

Sedimentation analysis of noninteracting and self-associating solutes using numerical solutions to the Lamm equation.

The potential of using the Lamm equation in the analysis of hydrodynamic shape and gross conformation of proteins and reversibly formed protein complexes from analytical ultracentrifugation data was investigated. An efficient numerical solution of the Lamm equation for noninteracting and rapidly self-associating proteins by using combined finite-element and moving grid techniques is described. It has been implemented for noninteracting solutes and monomer-dimer and monomer-trimer equilibria. To predict its utility, the error surface of a nonlinear regression of simulated sedimentation profiles was explored. Error contour maps were calculated for conventional independent and global analyses of experiments with noninteracting solutes and with monomer-dimer systems at different solution column heights, loading concentrations, and centrifugal fields. It was found that the rotor speed is the major determinant for the shape of the error surface, and that global analysis of different experiments can allow substantially improved characterization of the solutes. We suggest that the global analysis of the approach to equilibrium in a short-column sedimentation equilibrium experiment followed by a high-speed short-column sedimentation velocity experiment can result in sedimentation and diffusion coefficients of very high statistical accuracy. In addition, in the case of a protein in rapid monomer-dimer equilibrium, this configuration was found to reveal the most precise estimate of the association constant.

Biophysical Phenomena↗
PubMed1996

Comparison of low potassium Euro-Collins solution and standard Euro-Collins solution in an extracorporeal rat heart-lung model.

OBJECTIVE: Euro-Collins solution (EC) is routinely used in lung transplantation. The high potassium of EC, however, may damage the vascular endothelium, thereby contributing to postischemic reperfusion injury. To assess the influence of the potassium concentration on lung preservation, we evaluated the effect of a "low potassium Euro-Collins solution" (LPEC), in which the sodium and potassium concentrations were reversed. METHODS: In an extracorporeal rat heart-lung model lungs were preserved with EC and LPEC. The heart-lung blocks (HLB) were perfused with Krebs-Henseleit solution containing washed bovine red blood cells and ventilated with room air. The lungs were perfused via the working right ventricle with deoxygenated perfusate. Oxygenation and pulmonary vascular resistance (PVR) were monitored. After baseline measurements, hearts were arrested with St. Thomas' solution and the lungs were perfused with EC or LPEC, or were not perfused (controls). The HLBs were stored for 5 min or 2 h ischemic time at 4 degrees C. Reperfusion and ventilation was performed for 40 min. At the end of the trial the wet/dry ratio of the lungs was calculated and light microscopic assessment of the degree of edema was performed. RESULTS: After 5 min of ischemia oxygenation was significantly better in both preserved groups compared to the controls. Pulmonary vascular resistance was elevated in all three groups after 30 min reperfusion at both ischemic times. After 2 h of ischemia PVR of the group preserved with LPEC was significantly lower than those of the EC and controls (LPEC-5 min: 184 +/- 65 dynes * sec * cm-5, EC-5 min: 275 +/- 119 dynes * sec * cm * cm-5, LPEC-2 h: 324 +/- 47 dynes * sec * m-5, EC-2 h: 507 +/- 83 dynes * sec * cm-5). Oxygenation after 2 h of ischemia and 30 min reperfusion was significantly better in the LPEC group compared to EC and controls (LPEC: 70 +/- 17 mmHg, EC: 44 +/- 3 mmHg). The wet/dry ratio was significantly lower in the two preserved groups compared to controls (LPEC-5 min: 5.7 +/- 0.7, EC-5 min: 5.8 +/- 1.2, controls-5 min: 7.5 +/- 1.8, LPEC-2 h: 6.7 +/- 0.4, EC: 6.9 +/- 0.4, controls-2 h: 7.3 +/- 0.4). CONCLUSIONS: We thus conclude that LPEC results in better oxygenation and lower PVR in this lung preservation model. A low potassium concentration in lung preservation solutions may help in reducing the incidence of early graft dysfunction following lung transplantation.

Animals↗
PubMed2004

Histidine-tryptophan-ketoglutarate solution maximally preserves endothelium-derived hyperpolarizing factor-mediated function during heart preservation: comparison with University of Wisconsin solution.

BACKGROUND: The University of Wisconsin (UW) solution is used widely in heart preservation but has been demonstrated to be detrimental to the endothelial function. The present study compares the effect of histidine-tryptophan-ketoglutarate (HTK) and UW solutions on endothelium-derived hyperpolarizing factor (EDHF)-mediated function in porcine small coronary arteries. METHODS: An isometric force study was performed in a myograph and the membrane potential of a single smooth muscle cell was measured electrophysiologically. Small coronary arteries (diameter 457 +/- 15 microm) were incubated with UW (n = 8), HTK (n = 7) or Krebs solution (n = 15) at 4 degrees C for 4 hours. After washout, in the presence of indomethacin (Indo; 7 micromol/liter), N(G)-nitro-l-arginine (l-NNA; 300 micromol/liter) and oxyhemoglobin (HbO; 20 micromol/liter), bradykinin (BK; -10 to -6.5 log M)-induced relaxation was compared in U46619 (-8 log M) pre-contraction. EDHF-mediated hyperpolarization was elicited by BK (-6.5 log M) in the presence of Indo, l-NNA and HbO. RESULTS: BK-induced, EDHF-mediated relaxation was reduced from 93.6 +/- 2.8% to 79.7 +/- 4.6% after UW preservation (p = 0.01 by unpaired t-test and p = 0.005 by 2-way analysis of variance [ANOVA]), whereas HTK incubation did not decrease EDHF-mediated relaxation (87.0 +/- 6.5%, p = 0.3 by unpaired t-test and p = 0.6 by 2-way ANOVA, compared with control, and p = 0.001 by 2-way ANOVA, compared with UW). EDHF-mediated hyperpolarization (10.3 +/- 1.6 mV) was attenuated by UW exposure (3.4 +/- 0.6 mV, [p = 0.002] vs control), but not by HTK exposure (8.3 +/- 1.1 mV, [p = 0.3] vs control). CONCLUSIONS: HTK is superior to UW solution in protecting EDHF-mediated endothelial function in porcine small coronary arteries. The present findings supports the use of HTK solution in heart preservation.

Adenosine↗
PubMed1991

Effect of intraperitoneal administration of two different batches of albumin solutions on peritoneal solute transport in CAPD patients.

The effects of intraperitoneal administration of two different batches of human albumin (batch A and batch B) on peritoneal solute transport and dialysate white cell count were studied in 16 CAPD patients. The studies were done on two separate days during a 4-h dwell, one day without and one day with the intraperitoneal administration of 10 g/l human albumin. Marked differences were found between the two batches. The transport of all measured solutes increased during administration of batch A compared to the control experiments: urea 78% +/- 62%, lactate 51% +/- 38%, creatinine 96% +/- 54%, glucose 67% +/- 55%, inulin 27% +/- 33% IgG 126% +/- 80%, mean +/- SD; P less than 0.02). In the experiments with batch A the white cell count of the test bag was greater than that of the effluent ('night bag') before the test (13 +/- 5 vs 194 +/- 61 mm3/l; P less than 0.02). These effects were also observed when the dialysate was buffered to pH = 7.4 before inflow. Albumin batch B showed no effect on solute transport and white cell count. The effects of solute transport and white cell count are probably caused by the greater concentration of prekallikrein activator in batch A when compared to batch B (30.1 vs 0 U/l). Caution is warranted when human albumin is used for simultaneous measurement of peritoneal fluid and solute kinetics.

Absorption↗
PubMed1990

The superiority of an extracellular fluid solution over Euro-Collins' solution for pulmonary preservation.

Limited donor supply is the major factor restricting the application of lung transplantation. A uniformly reliable method of lung preservation would improve donor organ availability. At present, Euro-Collins' solution, an intracellular fluid-type solution, is most widely used in organ preservation. However, we have previously shown that initial pulmonary flush with an extracellular-type solution (low-potassium dextran solution [LPD]) provided better pulmonary preservation than Euro-C. In the present study, we used an in vitro-ventilated, blood-perfused rabbit lung model to examine whether the mechanism for this improvement was related to the effect of LPD during pulmonary flush or its effect during storage. Rabbit lungs were harvested and stored after pulmonary flush with different solutions (group 1: 400 ml of LPD; group 2: 400 ml of Euro-C; group 4: 300 ml of Euro-C followed by 100 ml of LPD; n = 5 in each group). The lungs were then preserved at 10 degrees C for 18 hr and reperfused with fresh venous blood. After 10 min of reperfusion, lungs in group 1 showed the highest PO2 (group 1: 124.4 +/- 7.7 mmHg; group 2: 46.2 +/- 9.4 mmHg P less than 0.01). Lungs in both group 3 and group 4 showed better lung function and lower wet/dry weight ratio than those in group 2. We conclude that LPD provides better lung preservation by its effects both on pulmonary flush and on storage.

Animals↗
PubMedDate not supplied

Positive solution of two-dimensional solute transport in heterogeneous aquifers.

The transport of contaminants in aquifers is usually represented by a convection-dispersion equation. There are several well-known problems of oscillation and artificial dispersion that affect the numerical solution of this equation. For example, several studies have shown that standard treatment of the cross-dispersion terms always leads to a negative concentration. It is also well known that the numerical solution of the convective term is affected by spurious oscillations or substantial numerical dispersion. These difficulties are especially significant for solute transport in nonuniform flow in heterogeneous aquifers. For the case of coupled reactive-transport models, even small negative concentration values can become amplified through nonlinear reaction source/sink terms and thus result in physically erroneous and unstable results. This paper includes a brief discussion about how nonpositive concentrations arise from numerical solution of the convection and cross-dispersion terms. We demonstrate the effectiveness of directional splitting with one-dimensional flux limiters for the convection term. Also, a new numerical scheme for the dispersion term that preserves positivity is presented. The results of the proposed convection scheme and the solution given by the new method to compute dispersion are compared with standard numerical methods as used in MT3DMS.

Convection↗
PubMed2004

Protective effects of B2 preservation solution in comparison to a standard solution (histidine-tryptophan-ketoglutarate/Bretschneider) in a model of isolated autologous hemoperfused porcine kidney.

Reperfusion injuries after organ transplantation affect graft function and influence long-term graft survival. As hypothermic storage, which minimizes the extent of unspecific tissue injury after ischemia and reperfusion, is significantly influenced by the composition of preservation solutions, strategies to optimize the different components may lead to longer graft survival. In the present study the effects of the preservation solution B2 on early renal function and histopathological changes were compared to histidine-tryptophan-ketoglutarate solution (HTK, Bretschneider) in a model of isolated blood-perfused porcine kidneys. B2-preserved kidneys displayed a lower renal resistance and significantly better creatinine clearance as compared to HTK. Mean differences were also found for filtration fraction and sodium fraction reabsorption. The functional data were also related to histopathological changes. Together, these data indicate that the recently developed preservation solution B2 offers new principles of preservation and is a useful preservation solution for experimental isolated perfused kidney models. B2 may also be an interesting model for optimizing preservation within other organ perfusion models.

Animals↗
PubMed1984

Investigations on the toxicity of bile salt solutions, Capmul 8210 and a bile salt-EDTA solution for common bile duct perfusion in dogs.

The following perfusion media for dissolving bile duct calculi were infused via a cutaneobiliary tube into the biliary tract of 12 mongrel dogs: 4.3% cholate solution, 0.34% chenodeoxycholate solution, Capmul, GMOC (special formulation of Capmul), BA-EDTA and 0.9% saline. Infusion lasted 50 h. Postmortem examination revealed hemorrhagic, partly phlegmonous cholangitis, acute duodenitis, necrosis and abscesses in the liver. The lesions were most pronounced after the cholate solution and with Capmul and GMOC, but were only detected to a slight extent after BA-EDTA and the chenodeoxycholate solution. 0.9% saline had no side effects. The investigations could demonstrate that it is the very irrigation media that today are recommended for treatment of bile duct stones in patients, that cause considerable morphologic side effects. The alternating administration of an EDTA solution with a Capmul preparation may diminish local toxicity of the latter.

Animals↗
PubMedDate not supplied

Can low-calcium peritoneal dialysis solution safely replace the standard calcium solution in the majority of chronic peritoneal dialysis patients?

OBJECTIVE: To evaluate the use of low-calcium solution as the standard solution in chronic peritoneal dialysis patients. DESIGN: Prospective long-term follow-up study over a one-year period. SETTING: University hospital. INTERVENTIONS: The change of the calcium concentration of the dialysate from 1.75 mmol/L to 1.25 mmol/L. MAIN OUTCOME MEASURES: Serum calcium and phosphorus concentration and intact parathyroid hormone (iPTH). PATIENTS: Fifty normo- and hypercalcemic patients using the standard 1.75 mmol/L calcium solution. RESULTS: Serum ionized calcium (iCa) decreased significantly during the first six months, resulting in a significant increment of iPTH (baseline value: 0.9-79, median 9.4 pmol/L; at six months: 1.1-111, median 20.6 pmol/L; p < 0.05). In 28 patients completing the study, iPTH remained significantly elevated, despite high normal iCa. At similar changes of iCa, patients with baseline iPTH > 20 pmol/L showed a significantly higher increase in iPTH than patients with low iPTH (24.0 vs 5.0; p < 0.01), despite a more than doubled dose of alfacalcidol and calcium carbonate (mean dose of 1580 increased to 3277 mg/day). During the follow-up, 21 episodes of hypercalcemia were observed. Phosphorus control was adequate. CONCLUSIONS: Low-calcium solution cannot be used as a standard solution, especially in patients with iPTH levels indicating mild or severe hyperparathyroidism, because in these patients iPTH may rise further.

Adult↗
PubMed1993

Comparison of intermittent injection of nondepolarizing solution with a single flush of UW solution for donor heart preservation.

Isolated canine hearts were preserved for 6 h at 5 degrees C followed by normothermic reperfusion for 2 h. The dogs were divided into two groups of nine hearts each; group 1 received a nondepolarizing preservation solution in multidose, and group 2 received a single flush of University of Wisconsin (UW) solution. Serum MB-CK and mitochondrial aspartate aminotransferase (m-AAT) concentrations and calcium overload during reperfusion were lower in group 1 than in group 2. At the end of reperfusion, myocardial ATP and total adenine nucleotide concentrations were higher and mitochondrial morphology appeared more intact in group 1 than in group 2. Left ventricular diastolic function was preserved better in group 1 than in group 2. These results suggest that in 6-h heart preservation, a nondepolarizing solution applied in multidose fashion protects the myocardium from the deleterious effects of hypothermia and cardioplegia better than a single flush of UW solution.

Adenosine↗
PubMed1979

Membrane pathways for water and solutes in the toad bladder: II. Reflection coefficients of the water and solute channels.

Urea and water transport across the toad bladder can be separately activated by low concentrations of vasopressin or 8 Br-cAMP. Employing this method of selective activation, we have determined the reflection coefficient (sigma) of urea and other small molecules under circumstances in which the bladder was transporting urea or water. An osmotic method for the determination of sigma was used, in which the ability of a given solute to retard water efflux from the bladder was compared to that of raffinose (sigma = 1.0) or water (sigma = 0). When urea transport was activated (low concentration of vasopressin), sigma for urea and other solutes was low, (sigma urea, 0.08--0.39; sigma acetamide, 0.55; sigma ethylene glycol, 0.60). When water transport was activated (0.1 mM 8 Br-cAMP) sigma urea approached 1.0 sigma urea also approached 1.0 at high vasopressin concentrations. In a separate series of studies, sigma urea was determined in the presence of 2 x 10(-5) M KMnO4 in the luminal bathing medium. Under these conditions, when urea transport is selectively blocked, sigma urea rose from a value of 0.12 to 0.89. Thus, permanganate appears to "close" the urea transport channel. These findings indicate that the luminal membrane channels for water and solutes differ significantly in their dimensions. The solute channels, limited in number, have relatively large radii. They carry a small fraction (approximately 10%) of total water flow. The water transport channels, on the other hand, have small radii, approximately the size of a water molecule, and exclude solutes as small as urea.

Animals↗
PubMed1994

Effect of topical cromoglycate solution on atopic dermatitis: combined treatment of sodium cromoglycate solution with the oral anti-allergic medication, oxatomide.

The effect of topically applied sodium cromoglycate solution in moderate to severe atopic dermatitis (AD) in children aged 4-14 years was studied in a double-blind, placebo-controlled, randomized group-comparative trial. One group of patients was treated with topical sodium cromoglycate solution and oral oxatomide whereas the other group was treated with topical placebo solution and oral oxatomide. After 4 weeks, AD improved significantly in the group treated with the sodium cromoglycate solution and oxatomide combination while marginal improvement was noted in the placebo. In addition, spontaneous IgE production from peripheral blood mononuclear cells decreased significantly in the sodium cromoglycate group but not in the placebo group. These results suggest that sodium cromoglycate solution may be very effective in combination with anti-allergic medication in the treatment of moderate to severe AD in children.

Administration, Oral↗
PubMed2001

Membrane and solution effects on solute rejection and productivity.

Limited understanding of the physical and chemical processes involved in membrane processes affects their widespread application in drinking water treatment. Insight into these processes was attained through a systematic manipulation of solution chemistry in membrane filtration with three 'loose' nanofiltration membranes. Eighteen known solutions were created varying pH, ionic strength, and major cation valence in the presence of a commercial humic acid. The membrances varied as well, including a non-ionic hydrophobic, a non-ionic hydrophilic, and an anionic hydrophilic membrane surface. Specific membrane productivity and TOC and conductivity rejection were monitored. In all cases, the presence of divalent cations decreased the rejection of both conductivity and organic matter. Divalent cations also greatly increased the rate of productivity decline over equivalent tests in solutions with monovalent cations. The most hydrophobic membrane had the greatest productivity decline rate under all solution conditions. The lowest ionic strength solutions showed the greatest TOC and conductivity rejection and the greatest rate of productivity decline for each of the membranes.

Filtration↗