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At least 19 recordsLinked to original sources

PubMed1992

A comparison of some simplified lactobionate preservation solutions with standard UW solution and Eurocollins solution for pancreas preservation.

Fifty-two rat pancreas transplants were performed to investigate which components of the UW solution were essential for successful pancreas preservation. LEW rats were used and the pancreata stored at 4 degrees C for 48 hr after flushing with commercial UW solution (ViaSpan, DuPont Pharmaceuticals) or a number of simplified solutions. Following storage the pancreata were transplanted into syngeneic recipient animals with streptozotocin-induced diabetes mellitus. Graft function was assessed by regular postoperative blood sugar measurements and a glucose tolerance test on the 14th postoperative day. With commercial UW solution, 4 of 9 recipients (44%) showed satisfactory graft function, while only one of 5 pancreata preserved using Eurocollins solution demonstrated satisfactory function. With solution A, in which hydroxyethyl starch and insulin were omitted from the standard UW solution, 3 of 7 recipients (43%) showed satisfactory function. Omission of glutathione, allopurinol, and adenosine from this solution (solution B) gave satisfactory function in 4 of 8 cases (50%). Substitution of raffinose in solution B with an equimolar concentration of glucose (solution C) resulted in acceptable function in 5 of 8 cases (62%). Increasing the raffinose concentration in solution B to 100 mM/L resulted in only 2 of 8 grafts (25%) with adequate function. By contrast, reversing the Na/K concentrations in solution A resulted in 100% (7/7) satisfactory graft function. We conclude that the rat pancreas can be successfully transplanted following 48-hr cold preservation using UW solution and some simplified versions, and that a substantially simplified lactobionate-based solution with a reversed sodium/potassium ratio improved survival.

Adenosine↗

PubMed1992

Collins' solution for cold storage of the heart for transplantation must be reversed with cardioplegic solution before reperfusion. A functional and metabolic study in the rat heart.

The following hypotheses were tested using an isolated perfused working rat heart model: (1) Collins' solution for cold storage of the heart is harmful for the heart during reperfusion; (2) a "reverse" of the intracellular-type Collins' solution with an extracellular-type cardioplegic solution before reperfusion is able to prevent this disadvantage of Collins' solution. The following two major groups (I and II) and five subgroups (-a to -e) in each group were prepared. In group I (reversed group); the hearts were initially stored in Collins' solution but were reversed by a 1-minute flush with cardioplegic solution followed by storage in cardioplegic solution for the last 1 to 180 minutes of the total 3-hour storage, that is, groups I-a (reversed for 1 minute), I-b (10 minutes), I-c (30 minutes), I-d (90 minutes), and I-e (180 minutes). In group II (nonreversed control group); the hearts were stored in Collins' solution throughout 3 hours and were also divided into five subgroups of groups II-a, II-b, II-c, II-d, and II-e in which only a 1-minute flush with Collins' solution was performed at the point corresponding to group I. The coronary flow in any of group II showed a marked decrease during the early reperfusion period. In group I, however, the coronary flow increased significantly in proportion to the duration of the reversing phase. The recovery of the aortic flow and the cardiac output in group I showed a bell-shaped pattern in relation to the duration of the reversing phase, reaching their peak values when reversed for 30 minutes (group I-c). The prolonged reverse (180 minutes) resulted in a deterioration of functional recovery associated with a poorer preservation of high-energy phosphates and a larger enzyme leakage. These results suggest that the beneficial effects of intracellular-type Collins' solution for cold storage of the heart were further improved by reversing Collins' solution with the extracellular-type cardioplegic solution for the last 30 minutes of the 3-hour cold storage because the disadvantageous vasoconstriction due to Collins' solution during reperfusion was successfully prevented by the replacement of intravascular and extravascular Collins' solution with cardioplegic solution before the reperfusion.

Animals↗

PubMed1992

Water and solute absorption from a new hypotonic oral rehydration solution: evaluation in human and animal perfusion models.

Controversy continues regarding the optimal composition of glucose electrolyte oral rehydration solutions for the treatment of acute diarrhoea. Four perfusion models (normal human jejunum, normal rat small intestine, cholera toxin treated secreting rat small intestine and rotavirus infected rat small intestine) have been developed and used to compare the efficacy of a hypotonic oral rehydration solution with standard United Kingdom British National formulary and developing world oral rehydration solutions (WHO). Despite obvious physiological and pathophysiological differences between these models there was general congruence in the water and solute absorption profiles of the different oral rehydration solutions. Hypotonic oral rehydration solution promoted significantly greater water absorption than other oral rehydration solutions in all rat models (p < 0.001) but apparently increased water absorption failed to achieve significance in human jejunum. British National Formulary-oral rehydration solution was unable to reverse net water secretion in both rotavirus and cholera toxin models. Net sodium absorption from hypotonic and WHO-oral rehydration solutions was significantly greater than from the low sodium British National Formulary-oral rehydration solutions (p < 0.001) except in the rotavirus model when absorption was similar to hypotonic-oral rehydration solutions. These findings show that there is agreement in the apparent efficacy of oral rehydration solutions in these animal and human perfusion models, and that improved water absorption with adequate sodium absorption may be achieved by reducing oral rehydration solution osmolality.

Adolescent↗

PubMed1991

Low-potassium UW solution for lung preservation. Comparison with regular UW, LPD, and Euro-Collins solutions.

University of Wisconsin solution has been used successfully in clinical kidney and liver preservation. The object of this study was to determine if low-potassium UW (LPUW) solution could be applied to pulmonary preservation. Rabbit lungs were stored after hypothermic pulmonary artery (PA) flush with four different solutions (group 1: low-potassium dextran (LPD) solution, group 2: high-potassium UW (HPUW) solution, group 3: LPUW solution, group 4: modified Euro-Collins (E-C) solution). The lungs were preserved at 10 degrees C for 30 hr and evaluated in an ex vivo ventilation/perfusion apparatus using fresh pooled venous rabbit blood. Mean PA flush pressures (MFP) during harvesting were significantly lower in groups 1 and 3 (8.1 +/- 1.0 mmHg and 7.3 +/- 0.6 mmHg, respectively; mean +/- SEM) than in groups 2 and 4 (15.5 +/- 1.7 mmHg and 12.3 +/- 0.9 mmHg, respectively). Lungs in groups 1 and 3 showed significantly higher PaO2 (103.5 +/- 8.0 mmHg and 89.3 +/- 7.2 mmHg) than groups 2 and 4 (48.3 +/- 7.7 mmHg, 66.7 +/- 4.7 mmHg). Groups 1 and 3 showed significantly lower wet/dry weight (W/D) ratios after reperfusion (6.21 +/- 0.15 and 6.39 +/- 0.23) than groups 2 and 4 (7.70 +/- 0.57 and 7.13 +/- 0.21, respectively). There were no significant differences in MFP, PaO2, PaCO2, mean pulmonary artery pressure, or W/D ratio between groups 1 and 3. These results suggest that LPUW solution may be as beneficial as LPD solution for pulmonary arterial flush and lung preservation.

Adenosine↗

PubMed1992

Detrimental effects of temperature on the efficacy of the University of Wisconsin solution when used for cardioplegia at moderate hypothermia. Comparison with the St. Thomas Hospital solution at 4 degrees C and 20 degrees C.

BACKGROUND: We have previously reported the superior protective properties of the University of Wisconsin (UW) solution compared with the St. Thomas solution (ST) in the rat heart subjected to the deep hypothermia (4 degrees C), thus demonstrating its possible use in cardiac transplantation. We thought it was important to evaluate the potential of the UW solution as a cardioplegic solution under the moderately hypothermic (20 degrees C) conditions of routine intraoperative myocardial protection. METHODS AND RESULTS: Isolated rat hearts were subjected to 60 minutes of ischemia at 4 degrees C or 30 (or 60) minutes of ischemia at 20 degrees C with UW, ST, and ST plus 100 mM K (ST + 100) solutions. Coronary flow, mechanical function, endothelial function, and ultrastructure were observed. Mean time (seconds) to infuse 10 ml of cardioplegic solution under constant pressure, a measure of coronary vascular resistance at 4 degrees C and 20 degrees C, respectively, for each solution were ST, 69.2 +/- 6.9 and 64.7 +/- 3.8; UW, 142.2 +/- 8.8 and 187.2 +/- 10.0 (p < 0.01); and ST + 100, 78.2 +/- 8.0 and 176 +/- 8.1 (p < 0.001). Mean recovery values of cardiac output (expressed as percentage of its preischemic value) after 60 minutes of ischemia at 4 degrees C were ST, 95.5 +/- 2.1%; UW, 93.0 +/- 2.4%; and ST + 100, 96.5 +/- 1.5%. After 30 minutes of ischemia at 20 degrees C, values were ST, 88.0 +/- 1.3%; UW, 72.2 +/- 3.6% (p < 0.005 versus ST); and ST + 100, 53.3 +/- 1.8% (p < 0.001 versus ST). CONCLUSIONS: The efficacies of UW and severely hyperkalemic cardioplegic solutions are affected by the degree of hypothermia under which they are used. Under moderate hypothermia (20 degrees C), severe hyperkalemia induces a marked increase in coronary vascular resistance that is associated with impaired myocardial protection. These studies discourage the use of UW for routine intraoperative cardioplegic arrest where the degree of hypothermia cannot be readily controlled. The ST solution does not share this constraint.

Adenosine↗

PubMed1992

[Acute diarrheal diseases. Treatment with carrot-rice viscous solution is more effective than ORS solution].

In infants and children, the treatment of acute diarrhoea with glucose-based electrolyte solutions results in rehydration but does not reduce the severity and duration of diarrhoea. In german-speaking countries, rice- and carrot-based solutions have a long tradition in the treatment of diarrhoea and may also reduce stool output and the duration of diarrhoea. Therefore, we evaluated the efficacy and safety of a carrot-rice-based rehydration solution (Na 57 mmol/L, n = 70) and two conventional glucose-based solutions with high or low sodium concentrations (Na 90 mmol/L, n = 48 or Na 55 mmol/L, n = 60) in a prospective study. The study subjects were Pakistani boys and girls between 3 and 48 months of age with mild or moderate dehydration. We measured duration of diarrhoea, fecal and urine output, fluid intake and serum electrolytes. The duration of diarrhoea was significantly lower (p less than 0.05) in the group receiving the carrot-rice based rehydration solution (59.5 +/- 30.9 h) than in the groups receiving the high-Na (75.5 +/- 30.5) and low-Na (74.8 +/- 32.5) glucose-electrolyte solutions. The mean fecal output (p less than 0.01) and fluid intake (p less than 0.001) were also significantly lower in the infants and children receiving the carrot-rice-based rehydration solution. No major electrolyte imbalances were observed in the three groups. We conclude that the carrot-rice-based rehydration solution was safe and more effective than two conventional glucose-electrolyte solutions in the rehydration of infants and children with acute diarrhoea.

Dehydration↗

PubMed1978

A new irrigating solution for intraocular surgery: TC Earle Solution.

Electrolyte solutions--Plasma-lyte, TC Medium 199, TC Medium 199 plus additional bicarbonate, TC Earle Solution, and glutathione bicarbonate Ringer Solution--were evaluated for effectiveness in maintaining corneal thickness and endothelial viability. The TC Earle Solution was shown to be the most effective commercially available solution; little difference was demonstrated between TC Earle Solution and the experimental GBR Solution. Glucose and bicarbonate were found to be essential ingredients in the efficacy of the TC Earle Solution.

Animals↗

PubMed1977

Effect of salt solutions on radiosensitivity of mammalian cells. III. Treatment with hypertonic solutions.

V79 Chinese hamster cells were treated with hypertonic solutions of NaCl or KCl and irradiated rat various times before, during, or after exposure to the solution. In solutions of molarities between 0-2 and 0-5 M, the cellular radiosensitivity increases with the molarity of the bathing solution. At these molarities, the hypertonic solution need not be present during irradiation to sensitize cells. Furthermore, radiosensitivity of cells could be increased by exposing cells for longer times to the hypertonic solution before irradiation. At higher salt concentrations (at 1-5 to 1-8 M), significant radioprotection is observed. Survival curve data showed that this protection was characterized by an increase in DO and a decrease in n, while the survival curves of cells sensitized with 0-465 M NaCl or with lower concentrations exhibited mainly changes in DO. The 1-55 M NaCl solution must be present during radiation to give a protective effect. Prolonged exposure to the salt before irradiation reduced the amount of radioprotection afforded by the salt. The results are discussed in terms of the effects of ions on histones, cellular water structure and the cell-aging cycle.

Cell Survival↗

PubMed1992

Water and solute absorption from hypotonic glucose-electrolyte solutions in human jejunum.

While oral rehydration therapy with glucose-electrolyte solutions is highly effective, the optimal formulation has not yet been defined. Recent clinical studies suggest that stool volume, and thus water losses, may be reduced if glucose is replaced by a polymeric substrate which reduces osmolality. It is possible that the efficacy of glucose monomer based oral rehydration solutions (ORS) will also improve if osmolality is decreased. Using jejunal triple lumen perfusion in healthy adult volunteers net water and solute absorption were studied from three hypotonic solutions with different sodium concentrations (46, 60, 75 mmol/l) but identical glucose concentrations (90 mmol/l), thus allowing osmolality to rise (210, 240, and 270 mOsm/kg, respectively). Results from these solutions (ORS 45:210, ORS 60:240, and ORS 75:270) were compared with the World Health Organisation oral rehydration solution (WHO-ORS). Greatest water absorption was seen with ORS 60:240 (p less than 0.01). Sodium absorption from ORS 60:240 and WHO-ORS was similar and greater than sodium absorption from ORS 45:210 (p less than 0.05). Potassium and glucose absorption were greater from ORS 60:240 than from any of the other hypotonic solutions (p less than 0.05) and were equal to absorption from WHO-ORS). These results in a short segment of healthy human jejunum suggest that hypotonic ORS containing monomeric glucose may increase water absorption.

Adolescent↗

PubMed1992

Bicarbonate is not the ultimate answer to the biocompatibility problems of CAPD solutions: a cytotoxicity test of CAPD solutions and effluents.

UNLABELLED: Human polymorphonuclear granulocytes (PMN) were tested for migration and phagocytosis after exposure to CAPD solutions and effluents sampled during the first hour of dialysis from patients treated with lactate or bicarbonate based CAPD-solutions. The effluents from the lactate based solutions (Dianeal and Lockolys) reduced the migration and enhanced the phagocytosis compared to values obtained in a standard cell culture medium. Both cell functions increased during the dialysis period. In contrast, the cell-function only changed slightly when 87b, a bicarbonate based CAPD-solution (pH = 7.4, [HCO3-) = 29mM), was employed. During the first 30 minutes, the cells performed at a higher level when exposed to the 87b effluent than when exposed to the lactate effluents. The observations further indicated that optimal conditions for PMNs are at a bicarbonate concentration of less than 20 mM and a lactate concentration of less than 15mM. IN CONCLUSION: PMN migration is reduced by both lactate and bicarbonate based CAPD solutions and effluents collected during the first hour of dialysis. The bio-compatibility of CAPD solutions may be improved by combining the lactate and bicarbonate buffering systems in a solution with a concentration of less than 20 mM of bicarbonate and less than 15 mM of lactate.

Biocompatible Materials↗

PubMed1992

Effect of an oxygen-enriched solution and multiple dosing of antegrade crystalloid cardioplegic solution on myocardial metabolism during coronary artery bypass graft operations.

The metabolic effect of excessive oxygenation and frequency of administration of antegrade crystalloid cardioplegic solution was assessed in 33 patients undergoing routine coronary artery bypass graft operations. Four patient groups were designed in which the initial aortic root injection was 1000 ml and then 100 ml administered through the vein grafts after completion of each distal anastomosis. The groups were divided as follows: group 1, single dose, normally oxygenated cardioplegic solution infused via the aortic root; group 2, single dose, high oxygen content cardioplegic solution infused via the aortic root; group 3, normally oxygenated cardioplegic solution with additional 250 ml doses via the aortic root every 20 minutes; group 4, high oxygen content cardioplegic solution with additional 250 ml doses via the aortic root every 20 minutes. In all groups myocardial mean septal temperature showed an immediate fall to approximately 11 degrees C with the initial aortic root doses and then a gradual rewarming to approximately 20 degrees C during the crossclamp period (mean 58.6 minutes). Metabolic parameters measured or calculated from the coronary sinus effluent were myocardial oxygen extraction, lactate production, base deficit, inorganic phosphate, glucose, potassium, creatine kinase (total and myocardial band fraction), and catecholamine production. There was no statistically significant difference in any of these determinations between each patient group. Furthermore, myocardial recovery, myocardial performance, and postoperative recovery characteristics were not different. We conclude that single or multidose aortic root crystalloid cardioplegic solution (either oxygen enriched or normally oxygenated) is equally effective in routine coronary artery bypass graft operations when septal temperatures are maintained between 15 degrees and 21 degrees C for a total arrest time of 60 minutes or less. In this study, increasing the volume cardioplegic solution given in multiple doses appeared to offer no significant metabolic or functional advantage in patients without complications who had satisfactory left ventricular function.

Cardioplegic Solutions↗

PubMed1978

[Oxygen transport by solutions for blood replacement in comparison with other infusion solutions (author's transl)].

To investigate the oxygen transport capacity of solutions for blood replacement the oxygen solubility coefficients (ml/ml atm) at 37 degrees C of 12 solutions for volume replacement were determined and compared with those of 12 solutions for parenteral nutrition, 4 electrolyte solutions and 5 solutions for osmotherapy. All solutions for volume replacement have lower values for oxygen solubility than human plasma which shows a very constant oxygen solubility value even under extreme conditions. For clinical use of volume replacement solutions it is recommended that the oxygen solubility of the substitute be considered when any of the following conditions presents: a) large amounts are infused (hemodilution), b) isobar of hyperbar oxygen therapy is employed (hyperoxia), c) the body temperature is lowered (hypothermia). This is valid especially in the case of any impairment of the microcirculation.

Biological Transport↗

PubMed1992

Oral salt supplements to compensate for jejunostomy losses: comparison of sodium chloride capsules, glucose electrolyte solution, and glucose polymer electrolyte solution.

Six patients with jejunostomies and residual jejunal lengths of 105 to 250 cm took the same food and water each day for eight study days. In random order, three methods of salt replacement were tested, each over 48 hours, against a period without added salt. During the three test periods the patients took 120 mmol of sodium chloride daily, as salt in gelatine capsules, as an isotonic glucose electrolyte (280 mOsmol/kg; 30 kcal) solution, and as a glucose polymer (Maxijul) solution (280 mOsmol/kg; 200 kcal). The daily stomal output remained constant for each patient during the four test periods but varied between patients from 0.60 to 2.84 kg (daily intestinal fluid balance 0.74-2.61 kg). Without a salt supplement, three patients lost more sodium from the stoma than they took in by mouth (-25, -94, and -101 mmol/day) and the mean sodium balance for all six subjects was -16 mmol (range -101 to 79) daily. Extra salt was absorbed with each form of supplement (p less than 0.05); no patient with the glucose electrolyte solution (mean 96, range 0 to 226 mmol), but one patient with the glucose-polymer solution (mean 96, range -25 to 164 mmol) and two with the salt capsules (mean 66, range -8 to 145 mmol) were in negative balance. Two patients vomited with the salt capsules. There was only a small increase in energy absorption (mean 115 kcal) with the glucose polymer solution compared with the glucose electrolyte solution. A sipped glucose electrolyte solution seems to be the optimal mode of sodium replacement in patients with a high output jejunostomy.

Adult↗

PubMed1992

The myocardial recovery mode after cold storage for transplantation with Collins' solution and cardioplegic solution. A functional and metabolic study in the rat heart.

Mechanisms and kinetics of the effects of the ionic composition of two different storage solutions, an intracellular type and an extracellular type, were analyzed by examining the myocardial functional and metabolic recovery processes during the early reperfusion periods after 3 hours of cold storage using an isolated perfused working rat heart model. The hearts were stored either in our own cardioplegic solution (group 1) or in Collins' solution (group 2) for 3 hours at 4 degrees C and were then reperfused. The electromechanical activity in group 1 was elevated, as indicated by a higher incidence of ventricular fibrillation at 5 minutes of reperfusion (group 1: 5/6; group 2: 0/5; p < 0.05). The coronary flow rate in group 2 was significantly lower, at least for the first 15 minutes after reperfusion, than that of group 1, suggesting the possible existence of vasoconstriction in group 2. Although myocardial oxygen uptake during this period was smaller in group 2, the recovery of myocardial high-energy phosphate levels was better and creatine kinase leakage was less in group 2. The recovery of aortic flow after 30 minutes of reperfusion was significantly better in group 2 (group 1, 59.1 +/- 5.8%; group 2, 71.7 +/- 6.0%; p < 0.01), although the early recovery was somewhat worse in group 2. These data suggest that the heart stored in an intracellular-type solution, compared with one stored in an extracellular-type solution, recovers in an electromechanically suppressed fashion during the early reperfusion phase, associated with a better metabolic recovery and a slower but larger functional recovery. The disadvantage of the intracellular-type solution, however, may be its effect on the increase of coronary vascular resistance during the early reperfusion period.

Animals↗

PubMed1978

Activity coefficients of salts in highly concentrated protein solutions. I. Alkali chlorides in isoionic bovine serum albumin solutions.

In order to understand the thermodynamic state of simple salts in living cells, the mean activity coefficients of LiCl, NaCl, KCl, RbCl, CsCl were determined in concentrated isoionic bovine serum albumin (BSA) solutions by use of the EMF method with ion exchange membrane electrodes. The protein concentration range extended up to 22 wt%, whereas the salt concentration was kept constant at 0.1 mole per kilogram water. These solutions may be regarded as crude but appropriate model systems for the cytoplasm of cells as far as type and magnitude of the macromolecular component influence on the chemical potential of the salts is concerned. The mean stoichiometric activity coefficients of the alkali chlorides in the isoionic BSA solutions decreased linearly with the protein molality; this decrease, however, did not exceed ca. 10% compared with the pure 0.1 molal salt solutions. Only very small differences in the behavior of the different alkali chlorides were observed. The results may be interpreted by the superposition of the effects of specific Cl- ion binding to BSA and BSA bound "non-solvent" water with probably electrostatic long range interactions of the BSA(Cl-)nu polyions with the salt ions in solution. The resulting mean activity coefficients, corrected for ion binding and non-solvent water, showed a very slight linear dependence on the protein concentration. The departure from the value in the pure 0.1 molal salt solutions did not exceed +/- 2%.

Biological Transport↗

PubMed1992

Survival of mouse morulae vitrified in an ethylene glycol-based solution after exposure to the solution at various temperatures.

Mouse morulae were exposed in one step to a vitrification solution (EFS, a modified PBS containing 40% ethylene glycol, 18% Ficoll, and 0.3-M sucrose) at various temperatures, then cooled rapidly in liquid nitrogen, and then warmed rapidly. All of the embryos exposed to the EFS solution for 0.5 min at 25 degrees C before vitrification developed in culture. However, survival rates were lower if the duration of exposure was prolonged to 2, 5, or 10 min. At lower ambient temperatures (20, 10, and 5 degrees C), high survival rates were associated with longer exposure to the EFS solution. The toxicity of the EFS solution was also lower at lower temperatures. The toxic injury of morulae was manifested as decompaction of the blastomeres. Among the three additives in the EFS solution, ethylene glycol, which can cross cell membranes, was responsible for the toxicity. The results show that the optimum time for exposure of the embryos to the EFS solution before rapid cooling varies with the ambient temperature, i.e., 0.5 min at 25 degrees C, 0.5-5 min at 20 degrees C, 2-5 min at 10 degrees C, and 2-10 min at 5 degrees C. If they are exposed for an optimum period, almost all mouse morulae can survive vitrification (94-100%).

Animals↗

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↗

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↗