Measurement of gastric pH in ambulatory esophageal pH monitoring

Ayazi, Shahin; Leers, Jessica M.; Oezcelik, Arzu; Abate, Emmanuele; Peyré, Christian G.; Hagen, Jeffrey A.; DeMeester, Steven R.; Banki, Farzaneh; Lipham, John C.; DeMeester, Tom R.; Crookes, Peter F.

doi:10.1007/s00464-008-0218-0

Cited by 28 publications

(22 citation statements)

References 12 publications

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“…10,11 The location of the upper border of the LES determined by HRM was variable when compared to the results of conventional manometry. Overall, there was only a moderate correlation between the two measurements with variation of as much as 3.4 cm noted.…”

Section: Discussionmentioning

confidence: 99%

The Value of High-Resolution Manometry in the Assessment of the Resting Characteristics of the Lower Esophageal Sphincter

Ayazi

Hagen

Zehetner

et al. 2009

Journal of Gastrointestinal Surgery

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Section: Discussionmentioning

confidence: 99%

The Value of High-Resolution Manometry in the Assessment of the Resting Characteristics of the Lower Esophageal Sphincter

Ayazi

Hagen

Zehetner

et al. 2009

Journal of Gastrointestinal Surgery

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“…The pH study was performed according to a previously described protocol. 16 Subjects and patients were instructed to follow a controlled diet, remain in an upright or sitting position until retiring to bed in the evening, avoiding eating or drinking between meals, refraining from chewing gum or smoking, perform normal activities at home or at work, and lie flat at night. All acid-suppressing medications were discontinued 3 (H2-blocking agents) or 14 days (PPIs) before the study.…”

Section: Esophageal Manometrymentioning

confidence: 99%

Loss of Alkalization in Proximal Esophagus: a New Diagnostic Paradigm for Patients with Laryngopharyngeal Reflux

Ayazi

Hagen

Zehetner

et al. 2010

Journal of Gastrointestinal Surgery

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“…This assessment focuses on characterizing variation in baseline gastric pH, a key model parameter that determines the delivery of Cr(VI) to the SI, and subsequent risk, using published gastric pH data (Ayazi et al, 2009). Ayazi et al reported a bimodal distribution for gastric pH, with the normal subgroup distributed about a median pH of 1.7–1.8, and a hypochlorhydria subgroup with a median pH of approximately 4.2 (Figure 7).…”

Section: Resultsmentioning

confidence: 99%

Integration of mechanistic and pharmacokinetic information to derive oral reference dose and margin‐of‐exposure values for hexavalent chromium

Thompson

Kirman²,

Hays³

et al. 2017

J of Applied Toxicology

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The current US Environmental Protection Agency (EPA) reference dose (RfD) for oral exposure to chromium, 0.003 mg kg−1 day−1, is based on a no‐observable‐adverse‐effect‐level from a 1958 bioassay of rats exposed to ≤25 ppm hexavalent chromium [Cr(VI)] in drinking water. EPA characterizes the confidence in this RfD as “low.” A more recent cancer bioassay indicates that Cr(VI) in drinking water is carcinogenic to mice at ≥30 ppm. To assess whether the existing RfD is health protective, neoplastic and non‐neoplastic lesions from the 2 year cancer bioassay were modeled in a three‐step process. First, a rodent physiological‐based pharmacokinetic (PBPK) model was used to estimate internal dose metrics relevant to each lesion. Second, benchmark dose modeling was conducted on each lesion using the internal dose metrics. Third, a human PBPK model was used to estimate the daily mg kg−1 dose that would produce the same internal dose metric in both normal and susceptible humans. Mechanistic research into the mode of action for Cr(VI)‐induced intestinal tumors in mice supports a threshold mechanism involving intestinal wounding and chronic regenerative hyperplasia. As such, an RfD was developed using incidence data for the precursor lesion diffuse epithelial hyperplasia. This RfD was compared to RfDs for other non‐cancer endpoints; all RfD values ranged 0.003–0.02 mg kg−1 day−1. The lowest of these values is identical to EPA's existing RfD value. Although the RfD value remains 0.003 mg kg−1 day−1, the confidence is greatly improved due to the use of a 2‐year bioassay, mechanistic data, PBPK models and benchmark dose modeling.

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Measurement of gastric pH in ambulatory esophageal pH monitoring

Abstract: There is an inverse, dose-dependent relationship between gastric pH and esophageal acid exposure. Negative 24-h esophageal pH test results for a patient with hypochlorhydria may prompt a search for nonacid reflux as the explanation for the patient's symptoms.

Cited by 28 publications

References 12 publications

The Value of High-Resolution Manometry in the Assessment of the Resting Characteristics of the Lower Esophageal Sphincter

The Value of High-Resolution Manometry in the Assessment of the Resting Characteristics of the Lower Esophageal Sphincter

Loss of Alkalization in Proximal Esophagus: a New Diagnostic Paradigm for Patients with Laryngopharyngeal Reflux

Integration of mechanistic and pharmacokinetic information to derive oral reference dose and margin‐of‐exposure values for hexavalent chromium

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