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PubMed1988

The effect of truncal vagotomy on the bicarbonate-ion secretion of the stomach in rat.

The effect of truncal vagotomy on the gastric bicarbonate-ion, H-ion and chloride-ion secretions of the rat was studied experimentally. In the first half hour after truncal vagotomy, besides the known decrease of the H-ion, also the bicarbonate-ion and chloride-ion secretions were found reduced. The decrease in bicarbonate ion secretion was smaller as compared to the H-ion secretion. After two hours, there was no difference in bicarbonate-ion and chloride-ion secretions as compared to the controls and to the vagotomized groups. According to their results, following truncal vagotomy applied in the surgical management of ulcer, the bicarbonate-ion secretion of the stomach decreases immediately after operation. This decrease is, however, only transitory the bicarbonate-ion secretion becoming normal within a short time.

Animals↗
PubMed1979

The effect of duodenal acidification on plasma secretin and gastrin and pancreatic bicarbonate secretion in man.

Plasma secretin, plasma gastrin and pancreatic bicarbonate output were measured in three healthy youths before and after a 10 min period of duodenal infusion of 50, 75 and 100 ml 100 mmol/1 HCl. Plasma secretin rose to a shortlived peak within 10 min, whereas plasma gastrin fell gradually to values significantly below the basal level 60 min after the start of duodenal acidification. Pancreatic bicarbonate output showed a more sustained increase following duodenal acidification. Significant positive correlations were obtained between plasma secretin and infused dose of HCl, between pancreatic bicarbonate output and infused dose of HCl and between plasma secretin and pancreatic bicarbonate output. The calculated maximal pancreatic bicarbonate output (Vmax) of 30.6 mEq/h and the calculated dose of secretin to elicit half maximal pancreatic bicarbonate output (S50) of 0.2 CU/kg-h following duodenal acidification were comparable to that seen after intravenous infusion of secretin. No significant correlation was found between plasma secretin and plasma gastrin. It is suggested that the pancreatic stimulation subsequent to duodenal acidification is mainly effected by release of secretin, and that the fall in plasma gastrin may be caused by a HCl-induced inhibition of gastrin release from the duodenum.

Adult↗
PubMed1983

Potentiation effect of cholecystokinin-octapeptide on pancreatic bicarbonate secretion stimulated by a physiologic dose of secretin in humans.

We studied the potentiation effect of cholecystokinin-octapeptide and secretin on pancreatic secretion of bicarbonate and trypsin in humans. The pancreatic bicarbonate and trypsin outputs were determined by using a triple-lumen duodenal tube and indicator dilution technique while gastric juice was completely aspirated. When cholecystokinin-octapeptide in varied doses, 2.6, 5.3, 10.9, 26.3, 52.6, and 109.4 pmol . kg-1 . h-1, was added to i.v. infusion of secretin in a physiologic dose, 0.03 clinical units (CU) . kg-1 . h-1, the bicarbonate outputs were significantly greater than those achieved by secretin or cholecystokinin-octapeptide alone or the sum of the bicarbonate outputs produced by each hormone. The potentiation effect of cholecystokinin-octapeptide occurred at the dose of 10.9 pmol . kg-1 . h-1. No further further augmentation on the bicarbonate output occurred when the dose of cholecystokinin-octapeptide was increased in the dose range greater than 10.9 pmol . mg-1 . h-1. No potentiation on pancreatic secretion of trypsin was apparent when the two hormones were given simultaneously. Thus, cholecystokinin-octapeptide in a relatively small dose range potentiated the pancreatic bicarbonate secretion stimulated by a physiologic dose of secretin. The pancreatic enzyme secretion does not appear to be potentiated by two hormones.

Adult↗
PubMed1983

[Bicarbonate dialysis: comparative study of its long-term effects].

Changes in blood bicarbonate, phosphate and lipid were followed up on 9 patients as they are dialyzed with an acetate containing dialysate (AC) during 2 years and with a bicarbonate containing dialysate (BC) during 2 more years. The mean (+/- SD) predialysis concentration of blood bicarbonate was 23.11 +/- 1.09 mmol/L on AC period and 26.72 +/- 1.26 mmol/L on BC period. The new bicarbonate concentration steady state was reached with a delay of about 3 months. The mean (+/- SD) predialysis phosphate concentration was lower during BC period (1.73 +/- 0.17 vs 1.95 +/- 1.26 mmol/L). Although the changes were not significant, less aluminium hydroxide (4.8 +/- 0.8 vs 6.0 +/- 1.3 g per day) was necessary to control blood phosphate during BC period. The most striking changes in this long term study was the tolerance of the patients on bicarbonate dialysis, where hypotension episodes and muscles cramps were reduced by 50% and headache, nausea and vomiting disappeared almost completely. Conversely, no significant changes in lipid status with changing dialysate could be found. The results of this long term study provide strong support for promoting bicarbonate containing dialysate for all hemodialyzed patients.

Acetates↗
PubMed1995

Site-selective effect of bicarbonate on amantadine renal transport: quinine-sensitive in proximal vs quinidine-sensitive sites in distal tubules.

The mechanism for bicarbonate enhancement of amantadine (A+) uptake was studied further. A selective modulatory effect of bicarbonate on the stereoselectivity of inhibition of A+ uptake by the stereoisomers, quinine (Q) and quinidine (QD), as reflected by the reversal of potency (Q > QD in KHS vs. QD > Q in phosphate), is reported. Studies were performed in bicarbonate (KHS) and phosphate buffers using purified cortical proximal (PT) and distal tubules (DT) from rat kidneys. Variations of extracellular K+ and Ca++ were used to assess the effect of membrane depolarization and calcium on A+ uptake by the tubules. K+ concentration manipulation (1.5-100 mM) did not change A+ uptake by PT or DT in KHS buffer. High Ca++ (5.0 mM) decreased A+ uptake by PT in KHS (P < .001), whereas in phosphate buffer, both 2.5 and 5.0 mM Ca++ decreased uptake (P < .001). In DT, 0.25 mM Ca++ enhanced A+ uptake (P < .05) in KHS, but 2.5 and 5.0 mM Ca++ decreased it in both buffers. Inhibition studies with Q and QD were performed to characterize the bicarbonate-dependent and bicarbonate-independent A+ transport sites further. Stereoselectivity of inhibition was observed in PT in all buffers used. Potency of Q was higher than QD in KHS but lower than QD in phosphate-buffered PT. QD potency remained unchanged. In phosphate-plus-bicarbonate-buffered PT, the inhibitory potencies for Q and QD increased, with the potency of QD being greater than in KHS (P < .001). For DT, Q and QD were equipotent in all buffers used.(ABSTRACT TRUNCATED AT 250 WORDS)

Amantadine↗
PubMed1995

Evaluation of the effects of saline versus bicarbonate-containing mixed salts solutions on rabbit corneal epithelium in vitro.

Rabbit corneas were incubated, over 4 h in vitro, with the corneal epithelial surface exposed to various solutions to assess their utility as incubation solutions for physiological, pharmaceutical or toxicological studies. The corneal endothelium was perfused with a 35 mM bicarbonate-mixed salts solution equilibrated at 36 degrees C. Corneal thickness, corneal hydration or epithelial cell appearance (as assessed by scanning electron microscopy) were found to be similar to in vivo if a 35 mM bicarbonate, mixed salts solution (equilibrated with 5% CO2-air) was used for the epithelium. Some swelling (14 microns h-1), increased hydration and minor cell exfoliation were seen if this 35 mM bicarbonate solution was equilibrated with 5% CO2-95% O2 (hyperoxia). Solutions with only 5 mM bicarbonate (0.5% CO2-air) produced rapid swelling, large increases in hydration and marked cellular damage. Slightly hypertonic (310 mOsm kg-1) solutions containing 5 mM bicarbonate caused some swelling at 15 microns h-1, small increases in hydration and some cell damage but the swelling and cellular damage were further reduced by making the solution slightly more hypertonic (325 mOsm kg-1) by addition of NaCl and KCl. Saline (NaCl 0.9% or 0.97%) or phosphate-buffered saline (PBS) (300 mOsm kg-1) produced swelling at 21-28 microns h-1, 30% increases in hydration and almost total destruction of the superficial cell layers. These studies confirm in vivo experiments that saline (and also buffered saline solutions) are rather toxic to the corneal epithelium and thus should not be used as epithelial incubation solutions. Even when using mixed salts solutions and even with bicarbonate present, small differences in composition can have marked effects on corneal thickness, hydration or cell appearance. Hyperoxic solutions appear to be mildly cytotoxic compared with normoxic solutions.

Animals↗
PubMed1995

The effects of sodium bicarbonate and sodium citrate on 600 m running time of trained females.

The effects of sodium bicarbonate and sodium citrate ingestion on 600 m running performance were assessed in 11 female track athletes and four trained female non-athletes. The subjects ingested either sodium bicarbonate (NaHCO3), sodium citrate or placebo approximately 2.5 hrs prior to the test runs in doses of 0.3 g/kg body weight in a double blind cross over design. Prior to and after exercise NaHCO3, H+, and lactate (HLa) concentrations were measured and running times were recorded. Pre- and post-experiment baseline testings were also performed. Data analysis was conducted using a Manova Repeated Measures design and dependent "t"-test. Although differences in running times were found 121.5 s, 119.9 s, 120.4 s in bicarbonate, citrate and placebo treatments respectively, they were not significant. The pH and concentrations of NaHCO3 were significantly elevated prior to and after the exercise when alkalinizing agents were ingested (p < 0.001). In bicarbonate treatment, prior to exercise pH was 7.40 and [NaHCO3] was 28.4 mEq/l, and after the exercise pH was 7.14 and [NaHCO3] was 17.9 mEq/l. In citrate treatment, prior to exercise pH was 7.40 and [NaHCO3] was 27.1 mEq/l, and after the exercise pH was 7.13 and [NaHCO3] was 16.6 mEq/l. There were no significant differences among the pre-exercise (2.3 mmol/l, 2.1 mmol/l, 2.2 mmol/l in bicarbonate, citrate and placebo treatments respectively) and after-exercise (11.8 mmol/l, 11.9 mmol/l, 11.0 mmol/l bicarbonate, citrate and placebo, respectively) HLa concentrations. This study demonstrated that, although alkali ingestion resulted in significant shifts in the blood acid-base balance, it failed to affect the 600 m running performance.

Acid-Base Imbalance↗
PubMed1996

Intestinal transport of water, sodium & glucose from an electrolyte solution with & without bicarbonate.

In this study we have evaluated the role of bicarbonate on water and sodium transport in normal and secreting ilea of rabbits as controversy exists regarding the inclusion of bicarbonate in oral rehydration solution (ORS). In anaesthetized rabbits 10 cm closed ileal loops were constructed and filled with 5 ml of an electrolyte solution with and without bicarbonate, which contained polyethylene glycol (PEG; mol wt 4,000) as a non-absorbable marker. The fluid was withdrawn after an hour and analyzed for PEG, sodium and glucose. Similar studies were carried out in loops one hour after exposure to 1 microgram/ml of purified cholera toxin. Body temperature was maintained at 37 degrees C during the experiment by using a lamp. The mean +/- SE of water and sodium absorption, with bicarbonate versus without bicarbonate, was -1.4 +/- 0.1 vs -1.1 +/- 0.3 ml/h/10 cm, and -340.8 +/- 23.0 vs -308.4 +/- 35.6 mM/h/10 cm, respectively from secreting rabbit ilea. A similar effect was observed in normal ilea. It is concluded that bicarbonate containing electrolyte solution has no additional promoting effect on water and sodium absorption in normal or secreting ilea of rabbits.

Animals↗
PubMedDate not supplied

A randomized controlled trial of a bicarbonate- and a bicarbonate/lactate-containing dialysis solution in CAPD.

OBJECTIVE: To evaluate the safety and efficacy of bicarbonate- and bicarbonate/lactate-based PD fluids. DESIGN: A randomly allocated prospective controlled trial lasting eight weeks. SETTING: Five renal units in Europe. PATIENTS: Individuals who have been treated by CAPD for at least three months and who have had at least one month's therapy with 40 mmol/L lactate PD fluid. Those with recent infection, diabetes or other serious illness are excluded. Forty-seven individuals have entered the study so far. INTERVENTIONS: Patients are randomly allocated to three groups. Group 1 receive 40 mmol/L lactate dialysate, Group 2 are given 38 mmol/L bicarbonate fluid and Group 3 are tested with a 25 mmol/L bicarbonate and 15 mmol/L lactate dialysate. OUTCOME MEASURES: The primary outcome measure is the plasma bicarbonate level. Adverse events and ease of use of the two-chambered bags used by Groups 2 and 3 are also being assessed. RESULTS: To date, plasma bicarbonate levels have been the same in all treatment groups up to the end of the trial period. There are no differences in serum lactate levels. No side effects are attributable to the test fluids. The patients have managed the two-chambered bags successfully. CONCLUSION: This trial is still ongoing, but to date, neutral bicarbonate based fluids have been as effective as lactate dialysate in treating uremic acidosis.

Adult↗
PubMed1973

Bicarbonate ion as a critical factor in photosynthetic oxygen evolution.

Bicarbonate ion, not dissolved CO(2) gas, is shown to increase 4- to 5-fold the rate of dichlorophenol indophenol reduction by isolated maize (Zea mays) chloroplasts. Glutaraldehyde fixed chloroplasts continue to exhibit bicarbonate-dependent 2,6-dichlorophenol indophenol reduction. Bicarbonate is shown to act close to the oxygen-evolving site, i.e. prior to the electron donation site of diphenyl carbazide to photosystem II. Dark incubation and light pretreatment of chloroplasts in various concentrations of bicarbonate, just prior to assay, indicate that bicarbonate binds to chloroplasts in the dark and is released again as the Hill reaction proceeds in the light. It is suggested that bicarbonate ions may play a critical role in the oxygen-evolving process in photosynthesis.

Journal Article↗
PubMed1984

Reevaluation of the role of bicarbonate and formate in the regulation of photosynthetic electron flow in broken chloroplasts.

The stimulation of the Hill reaction in CO(2)-depleted broken chloroplasts (Pisum sativum L. cv Rondo) by the total amount of dissolved CO(2) and HCO(3) (-) (bicarbonate(*)) was measured at several formate concentrations. Formate appears to be a competitive inhibitor of the bicarbonate(*) stimulation of electron flow. From these experiments we have obtained a reactivation constant (K(r)) of 78 +/- 31 micromolar NaHCO(3) and an inhibition constant (K(i)) of 2.0 +/- 0.7 millimolar HCOONa at pH 6.5. In the absence of formate, significant electron flow was measured at a bicarbonate(*) concentration well below K(r), suggesting that electron flow from Q, the primary electron acceptor of photosystem II, to plastoquinone can proceed when no bicarbonate(*) is bound to the regulatory site at the Q(B)-protein. If so, bicarbonate(*) stimulation of electron flow is mainly a diminution of the inhibition of electron flow by formate. In view of the results, it is proposed that regulation of linear electron flow by bicarbonate(*) and formate is a mechanism that could link cell metabolism to photosynthetic electron flow.

Journal Article↗
PubMed1992

The importance of bicarbonate in large volume anesthetic preparations. Revisiting the tumescent formula.

BACKGROUND: The tumescent local anesthetic approach is now being used more widely in dermatologic surgery. Although the original formula contains 12.5 mEq sodium bicarbonate per 50 mL of lidocaine, traditionally buffered solutions contain 1 mEq per 10 mL. OBJECTIVE: This study examines the effects of changing the concentrations of sodium bicarbonate in the tumescent formula. METHODS: Various concentrations of sodium bicarbonate in tumescent anesthetic preparations were measured for pH. RESULTS: Tumescent anesthetic preparations containing 5 mEq/L have a more physiologic pH (7.41) than the classic formula of 12.5 mEq/L (7.73). Clinical use of this reduced sodium bicarbonate solution showed no difference from the original formula. CONCLUSIONS: Sodium bicarbonate can be used in a 1 mEq per 10 mL of lidocaine ratio similar to other buffered anesthetic solutions. This solution is physiologic in pH. However, some thought should also be given to the pKa of lidocaine, which is at pH 7.9. To achieve this even higher concentration (20 mEq/L) bicarbonate must be added to the tumescent solution. Thought must be given to these concepts when tumescent solutions are used in large volumes.

Anesthesia, Local↗
PubMed1985

Milk production, nutrient digestion, and rate of digesta passage in dairy cows fed long or chopped alfalfa hay supplemented with sodium bicarbonate.

Effects of forage particle size and sodium bicarbonate on milk production, ruminal fermentation, ruminal fluid dilution rate, dry matter passage from the rumen, and nutrient digestion were measured in four Holstein cows in a 4 X 4 Latin-square experiment. Cows were fed ad libitum amounts of a diet of approximately 46% concentrate and 54% alfalfa hay. The 2 X 2 factorial arrangement of treatments were: 1) long stem alfalfa hay, 2) long stem alfalfa hay + 1.4% sodium bicarbonate (3.0% of concentrate), 3) chopped alfalfa hay (1.3 cm), and 4) chopped alfalfa hay + 1.4% sodium bicarbonate. Feed intake, milk yield, and milk composition were similar among treatments. Ruminal pH and concentration and molar percentages of volatile fatty acids were not altered. Decreasing feed particle size reduced ruminal fluid outflow as estimated by polyethylene glycol and chromium ethylenediamine tetraacetic acid dilution rates. Digestion of nutrients was decreased with chopped alfalfa hay but was not related to faster rate of passage of smaller size feed particles as determined by rare earth markers. Sodium bicarbonate increased water intake and tended to improve nutrient digestion. Absence of a significant effect of sodium bicarbonate upon rate of passage of chopped hay indicates that feed particles of this size are not significantly affected by small increases of dilution rate of ruminal fluid. Addition of sodium bicarbonate to an alfalfa hay (forage)-based diet did not improve production responses but did increase nutrient digestion.

Animal Feed↗
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↗
PubMed1993

In vitro comparison of bileaflet aortic heart valve prostheses. St. Jude Medical, CarboMedics, modified Edwards-Duromedics, and Sorin-Bicarbon valves.

The hydrodynamic performance of four currently used bileaflet heart valve prostheses (St. Jude Medical, CarboMedics, modified Edwards-Duromedics, and Sorin-Bicarbon) with a nominal tissue anulus diameter of 27 mm were measured in the aortic position. All experiments were performed in nonpulsatile flow and in an electrohydraulic, computer-controlled pulse duplicator simulating the left side of the human circulatory system. Testing conditions were set at cardiac outputs of 3.0, 4.5, 6.5, and 8.0 L/min at a constant heart rate of 70 beats/min. The Sorin-Bicarbon valve had the lowest pressure difference with regard to nonpulsatile (mean 5.4 mm Hg at 30 L/min) and pulsatile (mean 2.2 mm Hg at 8 L/min) flow, followed by the St. Jude Medical, CarboMedics, and modified Edwards-Duromedics valves. The leakage volumes under static and pulsatile flow conditions were lowest for the modified Edwards-Duromedics and Sorin-Bicarbon valves. The energy loss in pulsatile flow was lowest for the Sorin-Bicarbon valve, mainly because its systolic, closure, and leakage energy losses were low. Systolic sequential velocity profiles showed the most even flow distribution pattern for the St. Jude Medical and Sorin-Bicarbon valves. These findings correspond with lower overall Reynolds shear stress levels for the St. Jude Medical and the Sorin-Bicarbon valves than for the modified Edwards-Duromedics and CarboMedics valves.

Aortic Valve↗
PubMed1988

Effects of tromethamine and sodium bicarbonate buffers during cardiac resuscitation.

The effects on cardiac resuscitability of iso-osmolal solutions of tris-hydroxymethyl-aminomethane (tromethamine), sodium bicarbonate (NaHCO3) and sodium chloride placebo were compared in 30 domestic pigs using a well-established model of electrically induced cardiac arrest and resuscitation. We hypothesized that a carbon dioxide (CO2) consuming buffer like tromethamine would reduce and sodium bicarbonate would increase the respiratory acidosis of mixed venous blood, which had recently been demonstrated in our laboratory, Tromethamine did decrease and sodium bicarbonate did increase both arterial and mixed venous CO2 during cardiopulmonary resuscitation (CPR). Both concentrations of end-tidal CO2 and coronary venous PCO2 were significantly lower after tromethamine than after bicarbonate. However, tromethamine produced an unexpected vasodilator effect with reduction of mean aortic and coronary perfusion pressures to levels that are known to reduce resuscitability and survival independently of its buffer action. Neither resuscitability nor survival was altered by bicarbonate therapy in comparison with sodium chloride placebo.

Acid-Base Equilibrium↗
PubMed1981

Regulation of glucose utilization in chick embryo fibroblasts by bicarbonate ion.

The amount of glucose consumed by chick embryo fibroblasts in primary culture is strongly influenced by the presence of bicarbonate ion in the culture medium. Cells grown on glucose at physiologic concentration (5.5 mm) and in the absence of bicarbonate ion have a reduced rate of glucose utilization when compared to their counterparts cultivated in medium containing the usual 25 mM bicarbonate. The presence or absence of bicarbonate is without effect on chick embryo fibroblast proliferation over a 6-day growth period. Both lactic acid accumulation per mole of glucose consumed and the utilization of glutamine increase as a function of bicarbonate ion in the growth medium.

Animals↗
PubMed1987

Bicarbonate/chloride antiport in Vero cells: II. Mechanisms for bicarbonate-dependent regulation of intracellular pH.

The rates of bicarbonate-dependent uptake and efflux of 22Na+ in Vero cells were studied and compared with the uptake and efflux of 36Cl-. Both processes were strongly inhibited by DIDS. Whereas the transport of chloride increased approximately ten-fold when the internal pH was increased over a narrow range around neutrality, the uptake of Na+ was much less affected by changes in pH. The bicarbonate-linked uptake of 22Na+ was dependent on internal Cl- but not on internal Na+. At a constant external concentration of HCO3-, the amount of 22Na+ associated with the cells increased when the internal concentration of HCO3- decreased and vice versa, which is compatible with the possibility that the ion pair NaCO3- is the transported species and that the transport is symmetric across the membrane. Bicarbonate inhibited the uptake of 36Cl- both in the absence and presence of Na+. At alkaline internal pH, HCO3- stimulated the efflux of 36Cl- from preloaded cells, while at acidic internal pH both Na+ and HCO3- were required to induce 36Cl- efflux. We propose a model for how bicarbonate-dependent regulation of the internal pH may occur. This model implies the existence of two bicarbonate transport mechanisms that, under physiological conditions, transport OH(-)-equivalents in opposite directions across the plasma membrane.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗