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PubMed1995

Bicarbonate requirement for the donor side of photosystem II.

Suppression of electron flow (and its subsequent restoration with 3-10 mM NaHCO3) on the donor side of photosystem II is shown upon either a partial depletion of pea subchloroplast membranes in bicarbonate or the addition of 5-20 microM formate. At higher concentrations (5 mM) formate induces the known 'bicarbonate effect' on the acceptor side of photosystem II. In preparations depleted of manganese the restoration of electron flow with 0.1-0.2 microM MnCl2 (2-4 Mn per photosystem II reaction center) occurs only in the presence of bicarbonate and it is accompanied by an increased functional binding of manganese. Restoration of electron flow with diphenylcarbazide or NH2OH does not require the addition of NaHCO3. It is suggested that bicarbonate participates in the formation of the Mn-cluster capable of water oxidation or serves as a substrate for the water-oxidizing center.

Bicarbonates↗
PubMed1989

Stimulation of duodenal mucosal bicarbonate secretion in the rat by brain peptides.

Bicarbonate secretion by duodenal mucosa free of Brunner's glands was titrated in situ in anesthetized rats. Intracerebroventricular infusion of thyrotropin-releasing hormone (0.01-1 microgram/h), bombesin, gastrin-releasing peptide, or corticotropin-releasing factor increased the bicarbonate secretion and the transmucosal electrical potential difference. The increase in secretion in response to thyrotropin-releasing hormone and bombesin was prevented by cervical vagotomy. Intravenous administration of the alpha-adrenoceptor antagonist phentolamine increased the magnitude and duration of the response, suggesting that these two peptides in addition to eliciting vagal stimulation of the duodenal secretion, by sympathetic activation, inhibit the secretion. Intravenous thyrotropin-releasing hormone (3.6 mg/kg) did not affect the secretion, further indicating that effects were elicited within the central nervous system. Intracerebroventricular infusion of cholecystokinin-octapeptide or beta-endorphin had no effect on duodenal bicarbonate secretion or on the potential difference. The latter peptide was a potent stimulant of the secretion when injected intravenously and probably acts at a peripheral site. The central nervous control of duodenal mucosal bicarbonate secretion is thus influenced by some specific peptides that are known to occur in brain tissue, and duodenal protection against acid might be modulated by agents affecting this control.

Animals↗
PubMed1978

Influence of the CSF bicarbonate concentration on the ventilatory response to CO2 in relation to the location of the central chemoreceptors.

In anaesthetized cats, in which the cerebrospinal fluid bicarbonate concentration was varied by a ventriculocisternal perfusion technique, the ventilatory response to CO2 during hyperoxia could be satisfactorily described by VE = S(PCSFCO2 -B). Both the slope S and the intercept B were positively and linearly related to the CSF bicarbonate concentration. Assuming that the PCSFCO2 is equal to the PCO2 in extracellular fluid, it can be shown that VE is a linear, but not a unique function of the [H+] at the site of the chemoreceptors; the slope of this relation varies with the bicarbonate concentration at that site, possibly due to chemical complex formation between HCO-3 and Ca2+ or Mg2+. Changes in the B-value were related to the location of the central chemoreceptors with the models of Pappenheimer and Berndt aand their coworkers. It was found that changes in the CSF bicarbonate concentration are reflected for 60 per cent at the site of the central chemoreceptors, and that this was independent of the cerebral perfusion. Using Berndt's model a distance between CSF and central chemoreceptors of approximately 100 micron was found; this calculated distance is relatively insensitive to relationship (logarithmic or not) between ventilation and H+ concentration and to changes in cerebral perfusion, owing to the approximate nature of the diffusion model.

Animals↗
PubMed1984

Vasoactive intestinal polypeptide (VIP) in the pig pancreas: role of VIPergic nerves in control of fluid and bicarbonate secretion.

Vasoactive intestinal polypeptide (VIP) in the pig pancreas is localized to nerves, many of which travel along the pancreatic ducts. VIP stimulates pancreatic fluid and bicarbonate secretion like secretin. Electrical vagal stimulation in the pig causes an atropine-resistant profuse secretion of bicarbonate-rich pancreatic juice. In an isolated perfused preparation of the pig pancreas with intact vagal nerve supply, electrical vagal stimulation caused an atropine-resistant release of VIP, which accurately parallelled the exocrine secretion of juice and bicarbonate. Perfusion of the pancreas with a potent VIP-antiserum inhibited the effect of vagal stimulation on the exocrine secretion. It is concluded, that VIP is responsible for (at least part of) the neurally controlled fluid and bicarbonate secretion from the pig pancreas.

Animals↗
PubMed1995

In vitro effects of bicarbonate- versus lactate-buffered continuous ambulatory peritoneal dialysis fluids on peritoneal macrophage function.

At present, lactate is the most commonly used buffer in peritoneal dialysis fluids (PDFs). The high lactate concentration in combination with low original pH was demonstrated to suppress phagocytic function. We evaluated the in vitro effects of a newly formulated bicarbonate-buffered PDF containing glycylglycine (BiGG15 and BiGG40; Pierre Fabre Medicament, Castres, France) on peritoneal macrophage (PMO) function, and compared them with those of equiosmolar lactate-buffered PDF (1.5% and 4.25% glucose; pH 5.4 and pH 7.4) and control buffer. Peritoneal macrophages were isolated from the effluents of 10 continuous ambulatory peritoneal dialysis patients and tested for luminol- and lucigenin-enhanced chemiluminescence, superoxide (O2-) generation measured by cytochrome c reduction, killing capacity, and phagocytosis after incubation in the PDF used. Exposure of PMO to lactate-buffered PDF with an original pH of 5.4 resulted in a significant suppression of all PMO functions measured, compared with bicarbonate- and lactate-buffered PDFs with a pH of 7.4. At physiological pH (7.4), chemiluminescence generation of PMO exposed to BiGG15/40 was significantly higher compared with the corresponding equiosmolar lactate-buffered PDF (1,992 +/- 858 x 10(3) cpm/10(4) cells v 856 +/- 398 x 10(3) cpm/10(4) cells; P < 0.004). O2- generation, killing capacity, and phagocytosis were not significantly different after PMO exposure to bicarbonate compared with exposure to lactate-buffered PDF with a neutral pH. Irrespective of the buffer used, high-osmolality PDFs suppressed PMO function significantly more than low-osmolar PDFs. In conclusion, bicarbonate-buffered PDFs are less detrimental to PMO function than lactate-containing PDFs; these preliminary in vitro results need to be confirmed in vivo.

Bicarbonates↗
PubMed1995

Lower serum high-density lipoprotein-cholesterol concentration in patients undergoing maintenance hemodialysis with acetate than with bicarbonate.

The authors studied the effect of dialysate buffer composition on the serum lipid values in male patients undergoing maintenance hemodialysis. Twenty patients on acetate and 21 patients on bicarbonate hemodialysis were investigated. The serum concentrations of high-density lipoprotein (HDL)-, HDL2- and HDL3-cholesterol were significantly lower in patients on acetate than in those on bicarbonate dialysis. The results of this study suggest possible adverse effects of acetate hemodialysis on serum HDL-cholesterol compared with bicarbonate hemodialysis. Other possibly contributory factors such as age and time on dialysis could be excluded. However, a possible role of differences in drug therapy between acetate- and bicarbonate-treated dialysis patients could not be entirely excluded.

Acetates↗
PubMed1985

The ecophysiological significance of calcium bicarbonate in the urine of subterranean rodents: testing a hypothesis.

1. A comparative study of calcium and bicarbonate in the urine was carried out on the subterranean mole rat Cryptomys hottenttus and the terrestrial vlei rat Otomys irroratus. 2. The two species were kept on two different diets; carrots, a high calcium diet (41 mg/ 100 kg) or potatoes, a low calcium diet (14 mg/ 100g). 3. The results show that the urine of the mole rat contained high values of calcium bicarbonate on either diet. 4. The urine of the vlei rat showed high values of calcium bicarbonate only when kept on the high calcium diet. 5. From these results we assume that in subterranean rodents excretion of calcium bicarbonate is an adaptive mechanism to unload CO2 without increasing its concentration in the hypercapnic environment.

Adaptation, Physiological↗
PubMed1992

Prehospital bicarbonate use in cardiac arrest: a 3-year experience.

The American Heart Association no longer recommends the routine use of sodium bicarbonate in cardiac arrests. Reasons cited include the lack of documented effect on clinical outcome and potential adverse effects of metabolic alkalosis and hypernatremia. We reviewed 36 months of experience with 619 nontrauma adult, prehospital cardiac arrest patients to identify 273 successful resuscitations who had emergency department blood gases and electrolytes performed. Determination of complications associated with prehospital intravenous sodium bicarbonate and its impact on survival in resuscitated patients was undertaken. Fifty-eight patients did not receive sodium bicarbonate (NO HCO3 group) and had short cardiopulmonary resuscitation (CPR) times (7.4 +/- 5.5 minutes). Two hundred fifteen patients did receive sodium bicarbonate (HCO3 group) and had significantly longer CPR times (23.3 +/- 13.5 minutes, P less than or equal to .001). Both groups demonstrated routine early chest compression and hyperventilation as evidenced by no significant difference in paramedic response time or rate of intubations. Initial emergency department blood gas results of both groups were not significantly different. No patients in the NO HCO3 group had hypernatremia (sodium [Na]+ greater than 150), whereas four patients (2%) in the HCO3 group were hypernatremic. Eight patients (14%) in the NO HCO3 group and 37 patients (17%) in the HCO3 group were alkalotic with pH values greater than 7.49 (P = NS). Six patients (10%) of the NO HCO3 group and 24 patients (11%) of the HCO3 group had a metabolic component to the alkalosis as defined by a positive base excess value (P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed2006

Use of high-dose epinephrine and sodium bicarbonate during neonatal resuscitation: is there proven benefit?

For adults and pediatric age patients, high-dose intravenous epinephrine was recommended if standard-dose epinephrine failed to achieve return of spontaneous circulation. More recent trials suggest that high-dose epinephrine is not beneficial and may result in increased harm. There are no randomized clinical studies of high-dose versus standard-dose intravenous epinephrine in neonates. Routine use of high-dose epinephrine during neonatal resuscitation cannot be recommended. Although sodium bicarbonate has been used during neonatal resuscitation, the only randomized controlled trial of its use during brief neonatal resuscitation showed no benefit. Sodium bicarbonate infusion during neonatal cardiopulmonary resuscitation (CPR) has several known and potential side effects. The use of sodium bicarbonate infusion should be discouraged during brief CPR. Whether sodium bicarbonate is beneficial for infants who require prolonged CPR despite adequate ventilation is unknown.

Adrenergic Agonists↗
PubMed2005

Analysis of the acid-base reaction between solid indomethacin and sodium bicarbonate using infrared spectroscopy, X-ray powder diffraction, and solid-state nuclear magnetic resonance spectroscopy.

Indomethacin was used as a model compound to investigate acid-base reactions of solid materials, a common type of drug-excipient interaction. In a typical experiment, 500 mg of pure alpha-form indomethacin were mixed with 500 mg of sodium bicarbonate. The mixture was kept at 40 degrees C and at several relative humidities. The reaction was monitored by IR spectroscopy, X-ray powder diffraction, and solid-state NMR. At 40 degrees C and 80% RH, the reaction is nearly complete after 300 h. As observed by IR spectroscopy, the characteristic peaks of alpha-indomethacin disappear during the course of the reaction with the appearance of the characteristic peaks of the salt product, sodium indomethacin trihydrate. Solid-state NMR spectra and X-ray powder diffraction patterns of the reaction mixtures confirm the transformation of the mixtures to sodium indomethacin trihydrate; the reduced peak intensities in the diffraction patterns of the product relative to the initial mixtures indicate the formation of a microcrystalline product. A change in the reaction rate of sodium bicarbonate with alpha-indomethacin is observed when the mixtures are stored at different relative humidities. At 40 degrees C and 66% RH, the reaction of sodium bicarbonate with alpha-indomethacin is about 86% complete after 500 h. No detectable reaction was observed for sodium bicarbonate with the alpha form of indomethacin at 40 degrees C and 11% RH after 15 months. The combination of these solid-state characterization techniques is demonstrated to be essential to detect and monitor acid-base reactions in solid materials, which are impossible to monitor using solution-chemistry methods. The reaction kinetics at 66% RH fits the Jander equation very well, which is consistent with a diffusion-controlled mechanism.

Calibration↗
PubMed2001

Inhibition of steady-state mitochondrial ATP synthesis by bicarbonate, an activating anion of ATP hydrolysis.

Bicarbonate, an activating anion of ATP hydrolysis, inhibited ATP synthesis coupled to succinate oxidation in beef heart submitochondrial particles but diminished the lag time and increased the steady-state velocity of the (32)Pi-ATP exchange reaction. The latter effects exclude the possibility that bicarbonate is inducing an intrinsic uncoupling between ATP hydrolysis and proton translocation at the level of F(1)F(o) ATPase. The inhibition of ATP synthesis was competitive with respect to ADP at low fixed [Pi], mixed at high [Pi] and non-competitive towards Pi at any fixed [ADP]. From these results we can conclude that (i) bicarbonate does not bind to a Pi site in the mitochondrial F(1); (ii) it competes with the binding of ADP to a low-affinity site, likely the low-affinity non-catalytic nucleotide binding site. It is postulated that bicarbonate stimulates ATP hydrolysis and inhibits ATP synthesis by modulating the relative affinities of the catalytic site for ATP and ADP.

Adenosine Diphosphate↗
PubMed1989

Absence of a bicarbonate-depletion effect in electron transfer between quinones in chromatophores and reaction centers of Rhodobacter sphaeroides.

Higher plants, algae, and cyanobacteria are known to require bicarbonate ions for electron flow from the first stable electron acceptor quinone QA to the second electron acceptor quinone QB, and to the intersystem quinone pool. It has been suggested that in Photosystem II of oxygenic photosynthesis, bicarbonate ion functions to maintain the reaction center in a proper conformation and, perhaps, to provide the protons needed to stabilize the semiquinone (QB-). In this paper, we show that bicarbonate ions do not influence the electron flow, from the quinone QA to QB and beyond, in the photosynthetic bacterium Rhodobacter sphaeroides. No measurable effect of bicarbonate depletion, obtained by competition with formate, was observed on cytochrome b-561 reduction in chromatophores; on the flash-dependent oscillation of semiquinone formation in reaction centers; on electron transfer from QA- to QB; or on either the fast or slow recovery of the oxidized primary donor (P+) which reflects the P+QA- ----PQA or the P+QB- ----PQB reaction. The lack of an observed effect in Rhodobacter sphaeroides in contrast to the effect seen in Photosystem II is suggested to be due to the amino-acid sequence differences between the reaction centers of the two systems.

Bacterial Chromatophores↗
PubMed2001

Hydroxyl radical scavenging role of chloride and bicarbonate ions in the H2O2/UV process.

Simultaneous effect of inorganic anions, such as chloride and bicarbonate ions, on the scavenging of hydroxyl radicals (HO*) in the H2O2/UV process is the focus of this paper. The model compound of n-chlorobutane (BuCl) was used as the probe of HO*. By changing the pH conditions (2-9) and the concentrations of NaCl (0.25-2500 mM) and NaHCO3 (25 mM), the variation of HO* concentrations and the rate of H2O2 decomposition were compared. In general, the BuCl and H2O2 follow closely the first-order reaction within the first 10 and 40 min, respectively. In the presence of chloride alone at the pH range of 2-6, the HO* concentration in the reaction mixture increases with the increase of pH, and the HO* concentration at pH = 6 is 100 times of that at pH = 2. Including bicarbonate species in the solution, the peak HO* concentration was found at a certain pH, which shifts from 4, 5, to 5-7, as the molar ratios of chloride/bicarbonate species increase from 1 to 100. In addition, without bicarbonate species HO* concentration decreases significantly with increasing chloride concentration but remained rather unchanged beyond 1250 mM. In contrast, the HO* scavenging in the presence of bicarbonate species became relatively significant only when the chloride concentration reached beyond 250 mM. Throughout all experiments of different water quality conditions, the H2O2 decomposition rate remains rather unchanged.

Bicarbonates↗
PubMed1991

Peribulbar anesthesia. Effect of bicarbonate on mixtures of lidocaine, bupivacaine, and hyaluronidase with or without epinephrine.

The pH-adjustment of local anesthetic solutions with sodium bicarbonate may shorten onset time and improve spread of neural blockade. The authors undertook a prospective, double-masked, randomized study to see if a pH-adjusted mixture of lidocaine, bupivacaine, and hyaluronidase had faster and more complete onset of neural blockade, when used for peribulbar anesthesia. Eighty patients were randomly assigned to four groups and received a peribulbar block with one of four mixtures: group 1 (L) = 2% lidocaine, group 2 (LPH) = 2% lidocaine with 0.06 meq/ml sodium bicarbonate, group 3 (LE) = 2% lidocaine with 1:100,000 epinephrine (commercially prepared), or group 4 (LEPH) = 2% lidocaine with 1:100,000 epinephrine with 0.06 meq/ml sodium bicarbonate. To 5 ml of each of the preceding groups, 5 ml of 0.75% bupivacaine and 150 units of hyaluronidase was added. After each block, extraocular muscle movement was followed in each quadrant until akinesia developed. In the event of incomplete akinesia, blocks were supplemented at 20 minutes. The LPH group had the fastest onset to complete akinesia (7.0 +/- 2.0 minutes, mean +/- SEM) when compared with the onset time of all other groups (group 1 = 11.5 +/- 1.9 minutes, group 4 = 13.1 +/- 1.4 minutes, and group 3 = 16.0 +/- 1.8 minutes, significance greater than 95% by analysis of variance). Furthermore, when compared with group 3 by analysis of variance, group 4 had a faster onset time. The authors conclude that pH-adjustment of solutions with bicarbonate of either lidocaine/bupivacaine/hyaluronidase or commercially prepared lidocaine with epinephrine/bupivacaine/hyaluronidase decreases the onset time of peribulbar anesthesia.

Anesthesia, Local↗
PubMed1995

Intraocular irrigating solutions. A randomized clinical trial of balanced salt solution plus and dextrose bicarbonate lactated Ringer's solution.

BACKGROUND: Two intraocular irrigating solutions which differ principally by the presence of oxidized glutathione were compared in this randomized, masked, prospective study to discern differences in preservation of endothelial cell size. METHODS: Sixty-four patients undergoing extracapsular cataract extractions were randomized between two irrigating solution groups, Balanced Salt Solution (BSS) Plus (n = 30) and dextrose bicarbonate lactated Ringer's solution (n = 34). Preoperative and postoperative endothelial specular photomicrographs were analyzed for cell size and hexagonality, and the two groups were compared using repeated measures analysis of variance. RESULTS: Fifty-eight subjects (91%) completed the 2-month study. Change in cell size for the BSS Plus group (n = 28) (mean +/- standard error, 29.4 +/- 12.3 microns2) was not significantly different from the dextrose bicarbonate lactated Ringer's solution group (n = 30) (27.5 +/- 12.9 microns2) (P = 0.92). Groups did not differ significantly in percent hexagonality (P = 0.57) or in the variability of cell size (P = 0.61). CONCLUSION: The presence of glutathione in BSS Plus and other minor electrolyte differences between the solutions is not more advantageous with regard to endothelial cell size than dextrose bicarbonate lactated Ringer's solution for standard extracapsular cataract surgery. Cost per 500-microliters bottle of BSS plus is $62 compared with $9.80 for dextrose bicarbonate lactated Ringer's solution.

Aged↗
PubMed2001

Extreme metabolic alkalosis treated with normal bicarbonate hemodialysis.

Metabolic alkalosis (MA), defined as a primary increment in plasma bicarbonate concentration, is a common complication in hospitalized patients and is associated with high morbidity and mortality in severe cases. One of the major routes of compensation for MA (ie, the secretion of an alkaline urine) is lost in renal failure patients. We report three cases involving four episodes of extreme MA with an arterial pH value greater than 7.60, serum bicarbonate concentration greater than 55 mmol/L, and stupor or seizure. Profound vomiting or massive gastric drainage combined with concurrent oliguric renal failure was the underlying mechanism for severe MA. Hydration and normal central venous pressure failed to improve the MA. The extreme MA was reversed quickly and safely by conventional hemodialysis with normal bicarbonate dialysate of 25 to 28 mmol/L. To our knowledge, this is the first reported successful use of normal bicarbonate dialysate in the treatment of severe MA. We also found that either H(2) blockers or proton-pump inhibitors have a prophylactic effect on the formation of MA.

Adult↗
PubMed1996

A prospective comparison of bicarbonate dialysis, hemodiafiltration, and acetate-free biofiltration in the elderly.

Hemodiafiltration (HDF) and more recently acetate-free biofiltration (AFB) have shown good blood purification and cardiovascular stability in young and middle-aged hemodialysis patients. It is not clear if this is also valid for elderly patients. Twelve patients aged more than 70 years (mean age +/- SD, 76 +/- 4 years) on regular dialysis for at least 5 months were treated with bicarbonate dialysis (BD), HDF, or AFB in a randomized sequence and prospectively followed for 6 months (72 dialysis sessions/patient) for each procedure. The dialysis solution (containing bicarbonate), blood flow rate, and dialysate flow rate were the same with all the methods. During HDF and AFB solutions containing bicarbonate at a concentration of 27 to 30 mEq/L and 145 mEq/L, respectively, were infused postdilution at a rate of 66 +/- 7 mL/min and 2.81 +/- 0.12 L/hr, respectively. During the period of observation we evaluated the number of intradialytic hypotensions, the episodes of nausea, vomiting, headache (dialysis intolerance), body weight, the interdialysis weight gain, the duration of the dialysis session, the number of hospitalizations/patient, and the length of hospitalization/patient. At the end of each observation period we determined: Kt/V, protein catabolic rate, acid base balance, serum creatinine, serum calcium, serum phosphorus, alkaline phosphatases, and serum intact parathyroid hormone. After the switch from BD to either HDF or AFB, the results have shown a significant reduction of dialysis hypotension episodes (18 percent on BD, 14 percent on HDF, and 13 percent on AFB; BD v HDF, P = 0.001; BD v AFB, P = 0.0001; and HDF v AFB, P = NS) and of dialysis intolerance (3.3 percent on BD, 1.3 percent on HDF, and 1.1 percent on AFB; BD v HDF, P = 0.021; BD v AFB, P = 0.019; and HDF v AFB, P = NS). Kt/V improved significantly after the switch from BD to either HDF or AFB (1.17 +/- 0.06 on BD, 1.32 +/- 0.12 on HDF, and 1.32 +/- 0.13 on AFB; BD v HDF, P = 0.021; BD v AFB, P = 0.003; HDF v AFB, P = NS). Protein catabolic rate also improved in HDF and AFB compared with BD (0.90 +/- 0.12 on BD, 1.03 +/- 0.15 on HDF, and 1.04 +/- 0.14 on AFB; BD v HDF, P = 0.001; BD v AFB, P = 0.009; and HDF v AFB, P = NS). AFB showed a better correction of acidosis compared either with BD or HDF (serum bicarbonate, 20.3 +/- 1.1 mEq/L on BD, 20.8 +/- 2.2 mEqL on HDF, and 22.2 +/- 2.4 mEq/L on AFB; BD v HDF, P = NS; BD v AFB, P = 0.01; and HDF v AFB, P = 0.030). The other parameters observed did not differ. In conclusion HDF and AFB show a better dialysis efficiency and a better hemodynamic tolerance compared with BD. This fact is associated with an improvement in protein intake as assessed by kinetic criteria. Acetate-free biofiltration has the further advantage of a better control of the acid-base balance compared with BD and HDF. HDF and AFB are useful dialytic options to traditional BD hemodialysis even in patients older than 70 years.

Aged↗
PubMed2001

Changes in hydration, protein and proteoglycan composition of the collagen-keratocyte matrix of the bovine corneal stroma ex vivo in a bicarbonate-mixed salts solution, compared to other solutions.

Many solutions have been used to investigate the swelling properties of the mammalian corneal stroma but few of the solutions resemble the expected extracellular matrix fluid of the corneal stroma, and little information is available on whether incubation ex vivo causes significant changes in the gross composition of the stroma. From quality-selected recent post-mortem eyes of adult cattle, stroma preparations were cut from the central part of the cornea. The time-dependent changes in wet mass were assessed over 9 h at 37 degrees C, and the preparations then dried. Various solutions of known pH (6.88-8.32) and osmolality (<50-327 mosmol/kg) were used, and were assayed for protein and proteoglycan after the incubation. The rates and extent of stromal swelling were lowest in a glucose-supplemented mixed salts solution containing 35 mM bicarbonate (0.5% CO2) solution, marginally greater in a mixed salts solution containing 35 mM bicarbonate (5% CO2) or similar non-bicarbonate mixed salts solutions (including BSS), and progressively greater in phosphate-buffered saline (PBS), various phosphate buffers (10-67 mM) and saline solutions (0.025-1%), and greatest in water. The initial rates of swelling ranged from 44 to 451 mg/h and the secondary rates from 9 to 106 mg/h. In all solutions, protein and proteoglycans were detected, but these ranged from around 1 to 10% of the samples with the bicarbonate-buffered solutions, to around 30% with the use of some phosphate buffers or saline.

Animals↗