Esophageal pH monitoring developed a dependable external reference electrode. Using this technique to monitor esophageal acid exposure patients for periods up to 24 hours, DeMeester and Johnson were able to identify the most important parameters of esophageal acid exposure, and they developed a composite pH score to quantify gastroesophageal reflux. The initial 24-hour pH studies required hospitalization until the introduction of microcircuits in the 1980s that allowed portable esophageal pH monitoring in an outpatient setting. Gastroesophageal reflux disease (GERD) is a common disease in western countries. In the United States, 7% of the population experiences heartburn daily and 44% at least once a
6TMS neutral amino acid transporter family 6TMS neutral amino acid transporter family The 6TMS Neutral Amino Acid Transporter (NAAT) Family (TC# 2.A.95) is a family of transporters belonging to the Lysine Exporter (LysE) Superfamily. Homologues are found in numerous Gram-negative and Gram-positive bacteria including many human pathogens. Several archaea also encode MarC (see below) homologues. Some of these organisms have 2 or more paralogues. Most of these proteins are of about the same size (180-230 aas) although a few are larger. They exhibit 6 (or in some cases, possibly 5) putative TMSs. A representative list of members belonging to the NAAT family can be found in