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PubMed1993

Gastric bicarbonate secretion in high-relapsing, smoking duodenal ulcer patients.

Gastric bicarbonate secretion has been evaluated by Feldman's method in 48 duodenal-ulcer patients. The relationship between smoking, clinical ulcer outcome (healing and recurrence) and bicarbonate secretion has been analysed. Heavy smokers secreted higher bicarbonate ions than did non-smokers. High-relapsing patients produced lower bicarbonate output. These preliminary data suggest that an impaired gastric bicarbonate secretion is associated with smoking, a well-known ulcer-associated factor; further-more, it may single out high-relapsing duodenal ulcer patients.

Adult↗
PubMed1993

Effect of bafilomycin on proximal bicarbonate absorption in the rat.

To evaluate the relative importance of the V-type H(+)-ATPase in proximal bicarbonate reabsorption in vivo, proximal tubules of male and female Wistar rats (180 to 260 g) were perfused with bicarbonate-Ringer solution with and without the addition of 2 microM bafilomycin A1. Bafilomycin significantly increased stationary pH from 6.75 +/- 0.05 (N = 39) to 6.86 +/- 0.03 (N = 82), the stationary concentration of bicarbonate from 5.24 +/- 0.62 to 6.33 +/- 0.46 mM and the half-time of acidification from 3.72 +/- 0.22 to 4.65 +/- 0.25 s, and significantly decreased net bicarbonate reabsorption from 3.17 +/- 0.21 to 2.55 +/- 0.15 nmol s-1 cm-2, that is, by 20%. Since bafilomycin is considered to be a specific inhibitor for V-type H(+)-ATPase, these data establish 1) the existence of this type of transport in the rat proximal tubule and 2) that approximately a fifth of the total proximal bicarbonate reabsorption is due to this mechanism of transport.

Absorption↗
PubMed1995

Natriuretic response to acute sodium chloride or sodium bicarbonate infusions in humans.

We compared the natriuretic responses to acute sodium chloride or sodium bicarbonate loading. 2.25 mEq/kg of sodium as sodium chloride, or sodium bicarbonate was infused intravenously in 1 h. Sodium chloride infusion resulted in a gradual increase in urinary sodium excretion (UNaV) for 4 h after starting the infusion, while sodium bicarbonate infusion caused a transient increase in UNaV for the first 2 h followed by a decrease. The amount of sodium excreted over 4 h in the sodium chloride and sodium bicarbonate groups were 20.7 +/- 4.7 and 34.8 +/- 2.3% of the sodium loaded, respectively (p < 0.05). This difference could not be ascribed to divergent responses in glomerular filtration rate, aldosterone, atrial natriuretic peptide, or serum albumin concentration. The difference in UNaV might be caused by the differences in renal tubular handling of chloride and bicarbonate.

Adult↗
PubMed1977

Importance of bicarbonate in retinal function.

This study demonstrates a requirement for bicarbonate in retinal function. Omission of bicarbonate, with either phosphate or Tris used to maintain a constant pH, leads to significant changes in both the electroretinogram potentials and metabolism of the isolated rat retina. Electroretinograms in bicarbonate-free media show a selective loss of the b wave and a decline in the amplitudes of the a wave and Slow PIII. Substitution of phosphate for bicarbonate causes a 60 and 52% decrease in aerobic and anaerobic lactate production, respectively, but this substitution leads to a 27% increase in aerobic retinal ATP content. It is suggested that the electrical effects of bicarbonate-free media are due to a decrease in utilization of ATP below critical levels at critical sites.

Adenosine Triphosphate↗
PubMed1995

Prescription and surveillance of the acetate-free biofiltration sessions: the bicarbonate cycle.

A computerized system, structured by 4 different models concerning urea depuration, and bicarbonate and sodium handling in acetate-free hemodiafiltration has been conceived for integrated use covering each step of the therapeutic cycle, from a) the prescription of the session to b) its delivery, up to c) the dose-response analysis: the system, now fully developed for the bicarbonate cycle, covers both working areas; the medical one, with a program implemented on a Personal Computer, called Skipper which deals with steps a) and c), and the nursing area, with a program built into the dialytic equipment software. The Skipper program supports the prescription step (a) testing the session schedule by bicarbonate, sodium and urea kinetics. The dialytic equipment, (step(b)) using a different program, on the basis of the scheduled parameters memorizes the end-session plasma bicarbonate level and reacts to any modifications of the parameters regarding blood flow and fluid reinfusion flow suggesting opposite changes in order to reach the scheduled results. Finally (step (c)), the Skipper system statistically evaluates the observed end session bicarbonate plasma level with an expected value with upper and lower confidence bounds obtained by a multiple regression analysis performed on a large population of patients.

Acetates↗
PubMedDate not supplied

Effect of omeprazole on gastric bicarbonate secretion in patients with duodenal ulcer.

BACKGROUND: Omeprazole, a H+/K+ ATPase inhibitor, has been shown to reduce gastric bicarbonate secretion in cats. However, there has been no study on the effect of omeprazole on bicarbonate secretion in patients with duodenal ulcer (DU). METHODS: Fifteen men with duodenal ulcer (mean age 38 years, range 22-57) were included. Baseline gastric acid output, bicarbonate secretion, and parietal and nonparietal secretions were estimated before and after omeprazole therapy (20 mg/day) for four weeks. RESULTS: Omeprazole administration did not significantly alter bicarbonate secretion (3.3 [1.2] vs 2.4 [0.4] mmol/h), though there was significant reduction in gastric acidity (44.2 [6.6] vs 20.7 [4.6] mmol/L, p < 0.01). CONCLUSION: Omeprazole reduces acid secretion but does not affect gastric bicarbonate secretion in patients with DU.

Adult↗
PubMed2003

Serial Doppler echocardiographic evaluation of small-sized sorin bicarbon prostheses.

OBJECTIVE: The Sorin Bicarbon prosthesis (Sorin Biomedica, Saluggia, Italy) is a bileaflet valve with curved-profile leaflets, a rolling hinge mechanism, and a pyrolytic carbon-coated titanium alloy housing and sewing ring. Although the Sorin Bicarbon prosthesis has been implanted in greater than 80,000 patients, and reference values on the hemodynamic performance of valve prostheses are needed to avoid patient-prosthesis mismatch, few Doppler echocardiographic data are available on the prosthesis in the aortic position. The aim of this study is to provide a detailed echocardiographic evaluation of the hemodynamic performance and regression of left ventricular hypertrophy after aortic valve replacement with the Sorin Bicarbon prosthesis. METHODS: The study included 182 patients who received a 21-mm (n = 61) or 23-mm (n = 121) Sorin Bicarbon prosthesis for pure or prevalent aortic stenosis who underwent serial echocardiograms at 3, 6, and 12 months after aortic valve replacement. RESULTS: Mean and peak gradients significantly decreased (P <.001) during follow-up to values of 12 +/- 3 and 22 +/- 6 mm Hg for the 21-mm prosthesis and values of 11 +/- 4 and 19 +/- 6 mm Hg for the 23-mm prosthesis at 1 year. Left ventricular mass index showed a 17% decrease to 120 +/- 27 g/m(2) in recipients of the 21-mm prosthesis (P <.001) and a 21% decrease to 123 +/- 29 g/m(2) in recipients of the 23-mm prosthesis (P <.001). A larger prosthesis size was the only predictor of a higher left ventricular mass index regression. Among recipients of the 21-mm prosthesis, body surface area of greater than 1.85 m(2) was associated with a lower regression of left ventricular mass index. The effective orifice area index was 1.00 +/- 0.11 and 1.08 +/- 0.14 cm(2)/m(2) in recipients of the 21-mm and 23-mm prostheses, respectively. CONCLUSIONS: Size 21 mm and 23 mm Sorin Bicarbon prostheses show low transprosthetic gradients, with significant reduction of left ventricular mass index during the first postoperative year. The reported effective orifice areas might be useful for aortic valve replacement in patients with a small aortic annulus to avoid patient-prosthesis mismatch.

Aged↗
PubMed2005

Pharmacological study of BRS, a new bicarbonated Ringer's solution, in partially hepatectomized rabbits.

BACKGROUND AND OBJECTIVE: The effects of bicarbonated Ringer's solution were evaluated and compared with those of acetated Ringer's, lactated Ringer's and Ringer's solutions in partially hepatectomized rabbits. METHOD: Animals were randomly divided into six groups (n = 6 in each group): a sham-operated group, an operated group without infusion, and four operated groups with infusions of each of the four Ringer's solutions. Each Ringer's solution was intravenously administered at 40 mL kg(-1) h(-1) for 1.5 h. Arterial blood gases, plasma magnesium concentrations and cardiovascular parameters were analysed. RESULTS: The partial hepatectomy-induced decrement of base excess was inhibited by bicarbonated Ringer's solution more remarkably than by either lactated or plain solutions (P < 0.01). The alkalinizing effect of bicarbonated Ringer's solution tended to be more marked than that of the acetated solution but not significantly so. Plasma magnesium concentrations were well maintained by bicarbonated solution as compared to the other solutions (P < 0.01). CONCLUSIONS: These results suggest that bicarbonated Ringer's solution is the most suitable perioperative solution for metabolic acidosis and plasma electrolyte balance among the Ringer's solutions tested.

Acidosis↗
PubMed2005

Studies of bicarbonate binding by dinuclear and mononuclear Ni(II) complexes.

Bicarbonate ion reacts with the dinuclear nickel(II) complex containing the taec ligand (taec = N,N',N' ',N' ''-tetrakis(2-aminoethyl)-1,4,8,11-tetraazacyclotetradecane) in buffered aqueous solution to form the mu-eta(2),eta(2)-carbonate complex with a large effective binding constant for bicarbonate ion, log K(B) = 4.39 at pH = 7.4. In contrast, the dinuclear nickel(II) complex containing the o-xyl-DMC(2) ligand (o-xyl-DMC(2) = alpha,alpha'-bis(5,7-dimethyl-1,4,8,11-tetraazacyclotetradecan-6-yl)-o-xylene) does not react with bicarbonate or carbonate ion in aqueous solution. In propylene carbonate, the reaction of [Ni(2)(o-xyl-DMC(2))](4+) with bicarbonate proceeds rapidly to form the mu-eta(1),eta(1)-carbonate complex. The structure of this carbonate complex has been determined by an X-ray diffraction study that confirms the mu-eta(1),eta(1)-carbonate binding mode. A mononuclear analogue of [Ni(2)(taec)](4+), [Ni(2,3,2-tetraamine)](2+) does not form a detectable mononuclear or dinuclear product with bicarbonate ion in aqueous solution, but [NiDMC](2+) (DMC = 5,7-dimethyl-1,4,8,11-tetraazacyclotetradecane) reacts slowly with carbonate ion in aqueous solution to form a 2:1 complex.

Journal Article↗
PubMed1992

Bicarbonate Concentration by Synechocystis PCC6803 : Modulation of Protein Phosphorylation and Inorganic Carbon Transport by Glucose.

The ability of the cyanobacterium Synechocystis PCC6803 to transport inorganic carbon in the form of bicarbonate rapidly decreased following a shift from bicarbonate-limited growth to either excess bicarbonate supply or to photoheterotrophic growth on glucose. Nonmetabolizable analogs of glucose did not exert this effect. The rate at which the bicarbonate uptake rate declined was too rapid to be accounted for by dilution of the activity by culture growth and suggested that posttranslational modification may be involved. Several proteins that were unphosphorylated during bicarbonate-limited growth became phosphorylated during the shifts to high CO(2) conditions and to photoheterotrophic growth. A similar alteration in the profile of phosphopolypeptides was observed following a shift into the dark. The changes in protein phosphorylation were not blocked by chloramphenicol or rifampicin.

Journal Article↗
PubMed1984

Bicarbonate Uptake by Nitrifiers: Effects of Growth Rate, pH, Substrate Concentration, and Metabolic Inhibitors.

The ratios of bicarbonate uptake to substrate oxidation were measured for three genera of nitrifying bacteria. The ratios for the two ammonium oxidizers tested were essentially the same; 0.0863 +/- 0.0055 and 0.0868 +/- 0.0091 mumol of bicarbonate were taken up per umol ammonium oxidized for Nitrosomonas europaea and a Nitrosospira strain, respectively. For Nitrobacter sp., a ratio of 0.0236 +/- 0.0013 mumol of bicarbonate taken up per umol of nitrite oxidized was obtained. Cells were grown in substrate-limited continuous culture and in batch culture, with generation times ranging between 16 and 189 h for the ammonium oxidizers and 18 and 69 h for Nitrobacter sp. All ratios appeared to be independent of growth rates and pH. However, short-term changes in substrate concentration and certain metabolic inhibitors significantly changed the efficiency of bicarbonate uptake. The significance of these results to the application of the nitrapyrin-sensitive bicarbonate uptake method for measuring nitrification rates in natural samples is discussed.

Journal Article↗
PubMed1985

Dietary magnesium oxide interactions with sodium bicarbonate on cows in early lactation.

Thirty-six Holstein cows were fed a diet of 50% concentrate and 50% corn silage (dry matter) for 12 wk postpartum. Treatments were 0, .4, and .8% magnesium oxide with or without .8% sodium bicarbonate in a 2 X 3 factorial arrangement. Dry matter intake was not different among treatments although the combined buffers had higher intake. Milk production was higher for the .4% magnesium oxide treatments either alone or with sodium bicarbonate as compared with either the 0 or .8% magnesium oxide treatments. Ruminal pH was increased with addition of sodium bicarbonate either alone or together with magnesium oxide. Dietary addition of .4% magnesium oxide either alone or with sodium bicarbonate increased total volatile fatty acid in ruminal fluid. Propionate and valerate were depressed in both of the combined buffered diets. Fecal pH was increased with magnesium oxide addition either alone or with sodium bicarbonate. Increasing magnesium oxide increased magnesium in plasma. No interactions in animal performance were significant for the two buffers.

Ammonia↗
PubMedDate not supplied

[Evaluation of the use of sodium bicarbonate in a group of children with diarrhea, 10 per cent dehydration and metabolic acidosis].

Considering the disparity of criteria regarding the use of sodium bicarbonate in the management of infants with diarrhea, dehydration and metabolic acidosis, a prospective study was done in 25 infants (13 managed without and 12 with bicarbonate) where it was demonstrated; a) The use of bicarbonate does not lead to a more rapid correction of the metabolic acidosis. b) Bicarbonate should not be used in patients with serum bicarbonate levels of 5 mEq/1. or over. c) Patients with dehydration and metabolic acidosis show hyperglycemia that returns to normal when the dehydration is corrected. This fact is of great interest because these children should not be considered nor managed as diabetics.

Acidosis↗
PubMed1976

Bicarbonate and cyclic AMP content of pure human pancreatic juice in response to graded doses of synthetic secretin.

In seven healthy volunteers pure pancreatic juice was obtained by endoscopic cannulation of the papilla of Vater. Synthetic secretin was intravenously infused in doses doubled every 20 min. The volume of pancreatic juice was proportional to the log of the secretin dose. A significant rise (P less than 0.05) in pancreatic juice flow was elicited at a dose as low as 8.05 ng per kg per hr. Maximum flow rate approximating 250 mul per 5 min per kg of body weight was attained during infusion of 129 ng per kg per hr. At the same dose maximal bicarbonate outputs averaging 383 muEq per hr per kg of body weight were obtained, whereas bicarbonate ion concentration approached peak values (135 +/- 9 muEq per ml) at 32.2 ng per kg per hr. Bicarbonate concentrations showed a tendency to fall at supramaximal doses. The effect of increasing secretin doses on bicarbonate and cyclic AMP concentrations was remarkably similar (rs = 0.635, P less than 0.001) suggesting the participation of cyclic AMP in human pancreatic bicarbonate secretion.

Adult↗
PubMed1982

Importance of bicarbonate ion in the vitreous space.

Intraocular irrigating solutions used during vitrectomy must be safe for all tissues surrounding the vitreous space. Bicarbonate and glucose were essential to the maintenance of retinal function. In this study the optimum concentration of bicarbonate in the irrigating solution for the retina was determined electrophysiologically with the use of the in vitro eyecup of the rabbit. In 15 to 25 mmole/L of bicarbonate solutions, the electroretinographic (ERG) b wave was well maintained. Higher concentrations of bicarbonate (35 to 45 mmole/L), which have been considered to be advantageous for the integrity of the corneal endothelium, were shown to suppress the retinal activity. These results were also found in in vivo eyecup, as determined with ERG and visual evoked response. Properly performed open-sky vitrectomy, itself, does not cause severe damage to the normal retinal function.

Animals↗
PubMed1987

Improvements of metabolic imbalances after enteral sodium bicarbonate supplementation in infants of very low birth weight (VLBW).

One of the main points of clinical care is the catch-up growth of VLBW infants especially those of small gestational age (SGA). The required high amounts of protein are often not tolerated [1]. Metabolic imbalances due to immaturities of protein metabolism are described [2, 3] also in infants SGA feeding amounts of proteins comparable to mature newborns [4]. Remarkable signs of overloading by proteins are the elevation of amino acid and the bile acid concentrations in the serum [3, 5, 6]. In some of those cases [7] late metabolic acidosis (LMA) is to be seen. There is evidence in the literature that sodium bicarbonate influences nitrogen [8] and ionic balances [9] in newborn animals without any signs of acidosis, besides its simple buffer function. The aim of this study was to control changes of metabolic imbalances after bicarbonate supplementation before development of acidosis in predisposed infants. Therefore we determined parameters, which were significantly changed with LMA [6] during two feeding schedules: firstly, during bolus supplementation in infants feeding (2.0 +/- 0.4) g/kg BW.d protein and secondly during chronic supplementation of bicarbonate to (3.0 +/- 0.4) g/kg BW.d protein. In relation to the improvement of the nitrogen balance in growing lambs [7] we supposed comparable effect of bicarbonate on metabolic imbalances caused by protein overloading.

Bicarbonates↗
PubMed1990

Hemodynamic and hepatic pH responses to sodium bicarbonate and Carbicarb during systemic acidosis.

Rats subjected to ammonium chloride-induced metabolic acidosis were given alkalinization therapy with either sodium bicarbonate or Carbicarb. Ammonium chloride-induced severe metabolic acidosis had minimal effect on mean arterial blood pressure and cardiac output. This acidosis resulted in a small but statistically significant fall in intracellular liver pH (pHi) as measured with 31P magnetic resonance spectroscopy (7.01 +/- 0.05 vs 7.08 +/- 0.04, p less than 0.05). Sodium bicarbonate treatment resulted in systemic alkalinization and increases in arterial pCO2 as well as transient but extreme decreases in cardiac output and mean arterial pressure. Alkalinization with sodium bicarbonate also resulted in a transient but significant decrease in intracellular liver pH (7.02 +/- 0.06 at 5 min vs 7.09 +/- 0.06 at baseline, p less than 0.05). Carbicarb therapy resulted in systemic alkalinization without major changes in arterial pCO2, cardiac output, or mean arterial blood pressure. Moreover, Carbicarb effected a sustained intracellular alkalinization of the liver (phi = 7.12 +/- 0.07 at 5 min, p less than 0.05, pHi = 7.19 +/- 0.07 at 10 min, p less than 0.01, pHi = 7.16 +/- 0.06 at 15 min, p less than 0.01, vs baseline pHi = 7.05 +/- 0.06). These data suggest that Carbicarb may be a more effective buffer than sodium bicarbonate during conditions where ventilation is limited and hemodynamic instability is present.

Acidosis↗
PubMed1986

The effect of sodium bicarbonate and sodium citrate ingestion on anaerobic power during intermittent exercise.

The effect of sodium bicarbonate and sodium citrate ingestion on cycling performance in three 30 s Wingate Anaerobic Tests separated by 6 min recovery periods has been studied using 6 male subjects. Subjects ingested either sodium bicarbonate (B), sodium bicarbonate plus sodium citrate (BC), sodium citrate (C) or sodium chloride (P) 2.5 h prior to exercise in a dose of 0.3 g kg-1 body weight. Pre-exercise blood pH was 7.44 +/- 0.06, 7.42 +/- 0.05, 7.41 +/- 0.05 and 7.38 +/- 0.04 in the C, BC, B and P conditions respectively. Mean and peak power output were significantly reduced by successive Wingate tests but not significantly affected by the treatments. Performance in the second and third tests was highest following C, BC and B ingestion. The total work done in the 3 tests was 103%, 102% and 101% of that achieved in the P condition after C, BC and B ingestion respectively. The increased alkali reserve recorded subsequent to bicarbonate and citrate treatment reduced mean post-exercise acidosis, although pH was significantly higher only in the C condition (p less than 0.05) compared to P after each exercise bout. No significant differences in plasma lactate concentration were recorded at any time. Citrate ingestion appears to be most effective in elevating blood pH and [HCO3-], and in enhancing performance in short-term intermittent exercise. This study demonstrates that alkali ingestion results in significant shifts in the acid-base balance of the blood and has a small, but non-significant, effect on anaerobic power and capacity as measured in a series of 3 Wingate Anaerobic Tests.

Acid-Base Equilibrium↗