Bicarbonate (HCO3-) causes a significant and reversible stimulation of anion-inhibited electron flow in photosystem II of higher plants and cyanobacteria. To test if selected arginine (Arg) residues are involved in the binding of HCO3-, we utilized oligonucleotide-directed mutagenesis to construct Synechocystis sp. PCC 6803 mutants carrying mutations in Arg residues in the D2 protein. Measureme...

BACKGROUND: Diabetic ketoacidosis (DKA) is a life-threatening endocrine emergency, traditionally requiring arterial blood gas (ABG) analysis for diagnosis and monitoring. The aim of our study was to assess the comparability of arterial and venous blood samples for pH and bicarbonate measurements in patients with DKA. MATERIALS AND METHODS: Prospective, observational study of patients with suspe...

[1] While much of the dissolved organic carbon (DOC) within rivers is destined for mineralization to CO2, a substantial fraction of riverine bicarbonate (HCO3 ) flux represents a CO2 sink, as a result of weathering processes that sequester CO2 as HCO3 . We explored landscape-level controls on DOC and HCO3 flux in subcatchments of the boreal, with a specific focus on the effect of permafrost on ...

Pulmonary vasoconstriction is influenced by inactivation of nitric oxide (NO) with extracellular superoxide (O2-*). Because the short-lived O2-* anion cannot diffuse across plasma membranes, its release from vascular cells requires specialized mechanisms that have not been well delineated in the pulmonary circulation. We have shown that the bicarbonate (HCO3-)-chloride anion exchange protein (A...

A fall in blood pH was induced by intra-arterial infusion of HC1 in seawateradapted rainbow trout (Salmo gairdneri). The acute acidosis resulting from HC1 infusion caused a short-lived decrease in plasma bicarbonate concentration ([HCO3~]) and an increase in arterial CO2 tension (PaCO2). Erythrocyte pH and bicarbonate concentrations were not significantly altered by the infusion of acid. Inject...

In carbon dioxide (CO2) corrosion of steels, the bicarbonate ion (HCO3) is simultaneously the buffer for carbonic acid (H2CO3), the source of iron carbonate (FeCO3) precipitation, and the product of the cathodic reaction. In addition to spatial separation of the production of Fe2+ and HCO3, galvanic coupling between the steel and cementite (Fe3C) layers is the principal cause of internal acidif...

Uremic acidosis accompanies chronic renal failure in hemodialysis patients because of a retention of nonvolatile acids. Standard bicarbonate (39 mEq/L) and acetate (38 mEq/L) dialysates do not completely correct the acidosis. The acid-base and biochemical effect of a high-bicarbonate (42 mEq/L) dialysate was evaluated in 38 patients during high-efficiency and high-flux dialysis over 12 wk. All ...

OBJECTIVE There is controversy about the effects of high plasma bicarbonate concentration ([HCO3(-)]) and the CO2 response test. We analyzed the relationship between [HCO3(-)] and the variation in hydrogen ion concentration (pH) for a given change in PaCO2, and its effects upon CO2 response. DESIGN A retrospective study was carried out. SETTING Two intensive care units. PATIENTS Subjects ...

The efficacy of using calcium carbonate as an osmolar control treatment for acid-base studies in horses receiving alkalizing compounds was evaluated. Six mares were nasogastrically intubated with isomolar quantities of sodium or calcium as sodium bicarbonate or calcium carbonate or with water during three treatment periods. Doses of the carbonic acid salts were 500 mg/kg sodium bicarbonate mixe...