To evaluate ion transport mechanisms in bile duct epithelium (BDE), BDE cells were isolated from bile duct-ligated rats. After short-term culture pHi was measured with a single cell microfluorimetric set-up using the fluorescent pHi indicator BCECF, and calibrated with nigericin in high K+ concentration buffer. Major contaminants were identified using vital markers. In HCO3(-)-free media, basel...

Arterial base deficit/excess (BD/E) is commonly used marker of metabolic acidosis in critically ill patients, but requires an arterial puncture and blood gas analysis. We hypothesized that serum bicarbonate (HCO3), which can be routinely obtained, strongly correlates with arterial BD/E and provides equivalent predictive information. In addition, we evaluated predictive value of simplified acute...

In mammals, Ca2+ and HCO3- ions play a critical role in the regulation of sperm function, most likely by regulation of cAMP levels. Mammalian germ cells contain a soluble adenylyl cyclase (sAC) with properties distinct from the well characterized membrane-bound enzymes Here we investigated whether the cyclase expressed in mature spermatozoa has the properties of sAC and whether it is regulated ...

The cortical collecting duct (CCD) B cell possesses an apical anion exchanger dissimilar to AE1, AE2, and AE3. The purpose of these studies was to characterize this transporter more fully by examining its regulation by CO2 and HCO3. We measured intracellular pH (pHi) in single intercalated cells of in vitro microperfused CCD using the fluorescent, pH-sensitive dye, 2',7'-bis(2-carboxyethyl)-5(6...

Anion transport by the colonic mucosa maintains the hydration and pH of the colonic lumen, and its disruption causes a variety of diarrheal diseases. Cholinergic agonists raise cytosolic Ca2+ levels and stimulate anion secretion, but the mechanisms underlying this effect remain unclear. Cholinergic stimulation of anion secretion may occur via activation of Ca2+-activated Cl- channels (CaCCs) or...

B romide (Br) causes positive interference with all clinical laboratory methods for the detenmination of serum Cl (1 .2). Interference with Cl measurement is much greater with ion-selective electrode (ISE) technology (1 .3) than with coubometry (1 -4). We recently described a patient ingesting therapeutic amounts of pynidostigmine Br (MestInon1 , containing 1 8.4 mg of Br [30.6%j per 60-mg tabl...

OBJECTIVE To compare pancreatic duct cell function in smokers (current and past) and never smokers by measurement of secretin-stimulated peak bicarbonate concentration ([HCO3-]) in endoscopic collected pancreatic fluid (PF). METHODS This retrospective study was cross-sectional in design, recording demographic information (age, gender, etc.), smoking status (former, current, never), alcohol in...

Sciortino, Christopher M., and Michael F. Romero. Cation and voltage dependence of rat kidney electrogenic Na-HCO3 2 cotransporter, rkNBC, expressed in oocytes. Am. J. Physiol. 277 (Renal Physiol. 46): F611–F623, 1999.— Recently, we reported the cloning and expression of the rat renal electrogenic Na-HCO3 2 cotransporter (rkNBC) in Xenopus oocytes [M. F. Romero, P. Fong, U. V. Berger, M. A. Hed...

An evaluation of several potential factors limiting carbon dioxide excretion by rainbow trout (Oncorhynchus mykiss) red blood cells was performed in vitro using a recently developed radioisotopic assay. Red blood cell (RBC) CO2 excretion was reduced by pretreatment (30min) of blood with the carbonic anhydrase inhibitor acetazolamide (final nominal concentration 1024 mol l21) or the Cl/HCO3 exch...