Modulation of Rat Chorda Tympani NaCl Responses and Intracellular Na+ Activity in Polarized Taste Receptor Cells by pH

Mixture interactions between sour and salt taste modalities were investigated in rats by direct measurement of intracellular pH (pHi) and Na+ activity ([Na+]i) in polarized fungiform taste receptor cells (TRCs) and by chorda tympani (CT) nerve recordings. Stimulating the lingual surface with NaCl solutions adjusted to pHs ranging between 2.0 and 10.3 increased the magnitude of NaCl CT responses linearly with increasing external pH (pHo). At pH 7.0, the epithelial sodium channel (ENaC) blocker, benzamil, decreased NaCl CT responses and inhibited further changes in CT responses induced by varying pHo to 2.0 or 10.3. At constant pHo, buffering NaCl solutions with potassium acetate/acetic acid (KA/AA) or HCO3−/CO2 inhibited NaCl CT responses relative to CT responses obtained with NaCl solutions buffered with HEPES. The carbonic anhydrase blockers, MK-507 and MK-417, attenuated the inhibition of NaCl CT responses in HCO3−/CO2 buffer, suggesting a regulatory role for pHi. In polarized TRCs step changes in apical pHo from 10.3 to 2.0 induced a linear decrease in pHi that remained within the physiological range (slope = 0.035; r2 = 0.98). At constant pHo, perfusing the apical membrane with Ringer's solutions buffered with KA/AA or HCO3−/CO2 decreased resting TRC pHi, and MK-507 or MK-417 attenuated the decrease in pHi in TRCs perfused with HCO3−/CO2 buffer. In parallel experiments, TRC [Na+]i decreased with (a) a decrease in apical pH, (b) exposing the apical membrane to amiloride or benzamil, (c) removal of apical Na+, and (d) acid loading the cells with NH4Cl or sodium acetate at constant pHo. Diethylpyrocarbonate and Zn2+, modification reagents for histidine residues in proteins, attenuated the CO2-induced inhibition of NaCl CT responses and the pHi-induced inhibition of apical Na+ influx in TRCs. We conclude that TRC pHi regulates Na+-influx through amiloride-sensitive apical ENaCs and hence modulates NaCl CT responses in acid/salt mixtures

Design, Implementation, and Evaluation of a Computerized System to Communicate with Patients with Limited Native Language Proficiency in the Perioperative Period

BACKGROUND: Effective communication with patients having limited proficiency in the native language of anesthesia care providers during the perioperative period is often challenging. We describe how we developed, implemented, and evaluated a computerized system to convey frequently used prerecorded phrases related to perioperative anesthesia care in the languages we most often encounter in such patients. METHODS: Phrases were chosen through a consensus process among anesthesia department members. These included routine sayings used to inform patients about what they should anticipate, what interventions we are performing, and how they can participate. Common questions requiring a "yes" or "no" answer were also identified. We recorded these phrases using native speakers who were both knowledgeable medically and familiar with the culture of the patients to provide accurate translations. We developed a software application that categorically grouped the phrases and allowed care providers to select a phrase and play the associated sound file to the patient and deployed the program on our touchscreen-enabled anesthesia information management system workstations. A convenience sample of obstetrical patients speaking a Chinese dialect with whom the language program was used were asked to complete an anonymous questionnaire, translated into Chinese, about their experience. Ninety-five percent lower confidence limits (LCLs) were calculated for response proportions. RESULTS: We approached 25 parturients with varying levels of English comprehension, and all agreed to use the language program. Each used it throughout her interaction with the anesthesia care providers during labor and delivery, and all patients completed the survey. Acceptance of the process was high, with all patients indicating that they would like to use it again were they to return for another procedure requiring anesthesia. Eighty-eight percent (LCL = 73%) indicated that having instructions in their native language made them feel more relaxed, whereas the experience was neutral in the remainder. Comprehension of the phrases presented was high, with 96% (LCL = 83%) indicating that they understood all instructions. Ninety-six percent (LCL = 83%) of patients indicated that they would be likely to refer friends and family to our institution based on the availability of this device. CONCLUSIONS: Although patient safety likely could be improved by use of a communication device such as the one we developed, our study was insufficiently powered to be able to measure this potential improvement. The process we describe should be useful wherever anesthesia care providers are not able to communicate in the same language as their patients. (Anesth Analg 2011;112:106-12