Using a chronoamperometric technique with carbon-fiber microelectrodes and neural recordings, we simultaneously measured the effects of the following procedures on catecholamine efflux (delta CA) and frequency of chemosensory discharges (fx) from superfused cat carotid body: 1) the addition of CO2-HCO3- to Tyrode solution previously buffered with N-2-hydroxyethylpiperazine-N'-2-ethane-sulfonic ...

BACKGROUND The pathogenic mechanisms involved in Helicobacter pylori-induced duodenal mucosal injury are incompletely understood. In the present study, we sought to investigate the effect of H. pylori vacuolating cytotoxin (VacA) on duodenal mucosal bicarbonate (HCO3-) secretion. METHODS Concentrated bacterial culture supernatants from an H. pylori wild-type strain producing VacA with s1/m1 g...

At physiological concentrations of HCO3- and CO2, Mn(II) catalyzes disproportionation of H2O2. This catalase-like activity is directly proportional to the concentrations of Mn(II) and H2O2, and it increases exponentially with increases in pH. The effect of increasing pH is almost completely attributable to the concomitant increase in HCO3- concentration. The rate is proportional to the third po...

A combined increase in seawater [CO2 ] and [H(+) ] was recently shown to induce a shift from photosynthetic HCO3 (-) to CO2 uptake in Emiliania huxleyi. This shift occurred within minutes, whereas acclimation to ocean acidification (OA) did not affect the carbon source. To identify the driver of this shift, we exposed low- and high-light acclimated E. huxleyi to a matrix of two levels of dissol...

OBJECTIVES In 1981, Peter A. Stewart published a paper describing his concept for employing Strong Ion Difference. In this study we compared the HCO3 levels and Anion Gap (AG) calculated using the classic method and the Stewart method. METHODS Four hundred nine (409) arterial blood gases of 90 patients were collected retrospectively. Some were obtained from the same patients in different time...

An optical method was used to continuously monitor intracellular pH (pHi) in single cultured LLC-PK1 cells. Rapidly growing or quiescent cells, attached to coverslips, were loaded with the pH-sensitive dye 4',5'-dimethyl-5(and -6)-carboxyfluorescein by exposing them to the dye's permeant precursor. pHi was calculated from the intracellular absorbance spectrum of the dye in a single cell. For ce...

The nature of the intracellular pH-regulatory mechanism after imposition of an alkaline load was investigated in isolated human peripheral blood neutrophils. Cells were alkalinized by removal of a DMO prepulse. The major part of the recovery could be ascribed to a Cl-/HCO3- counter-transport system: specifically, a one-for-one exchange of external Cl- for internal HCO3-. This exchange mechanism...

BSC-1 kidney epithelial cells derived from the African green monkey are known to express a Na+HCO3- symport (Jentsch, T. J., Schill, B. S., Schwartz, P., Matthes, H., Keller, S. K., and Wiederholt, M. (1985) J. Biol. Chem. 260, 15554-15560). In the present work, 4,4-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS)-sensitive 22Na+ uptake into confluent monolayers of BSC-1 is measured in the pr...

This work aims to investigate the hydrochemical characteristics and formation mechanisms of shallow groundwater in a part Nanchang section Ganfu plain. The data from 90 samples were interpreted by methods mathematical statistics, Piper diagrams, Gibbs plots, ratio graphs ions, geochemical modeling. results show that is weakly acidic, average concentration cation decrease Ca2+ > Na+ Mg2+ K+, ...

Sodium-bicarbonate cotransport in retinal glial cells was studied in the everted eyecup preparation of the rat. Intracellular pH was monitored with the indicator dye BCPCF and fluorescence confocal microscopy. Raising the K+ concentration from 3 to 12 mM in HCO3- -buffered perfusate evoked an intracellular alkalinization in both astrocytes and Müller cells. The alkalinization developed more rap...