A novel placement method of the Bravo wireless pH monitoring capsule for measuring intragastric pH

Colorimetric pH-sensing of artificial gastric fluid using naphthalimide-based CH acids

In this study, we introduce novel colorimetric pH-sensing probes based on naphthalimide malonate derivatives. These probes were synthesized by reacting 4-bromo-1,8-naphthalimide with various malonates, including malononitrile, ethyl cyanoacetate, and diethyl malonate. Each derivative exhibited distinct pH-sensing characteristics due to their differing CH acidities. The malononitrile-based probe, NPI-N2, demonstrated pronounced chromogenic pH-signaling behavior, transitioning from colorless to red-violet, accompanied by a decrease in fluorescence intensity. Notably, NPI-N2 retained its pH-sensing capability in the presence of common metal ions, anions, and pepsin, a key component of gastric fluid. The pKa of NPI-N2 was determined to be 3.08 through pH-dependent absorbance curve fitting. To modulate the pH-sensing range, ester-nitrile (NPI-EN) and diethyl ester (NPI-E2) subunits were incorporated into the naphthalimide framework, resulting in increased pKa values of 6.73 and 10.76, respectively. The pH-signaling mechanism of NPI-N2 was elucidated by 1H and 13C NMR spectroscopy, revealing deprotonation of the malononitrile moiety and subsequent resonance extension through the naphthalimide structure. To facilitate practical pH determination, NPI-N2 was integrated into a paper-based test strip, enabling convenient and reliable pH measurement of artificial gastric fluid.

A novel placement method of a calibration-free pH capsule for continuous wireless measurement of intragastric pH in horses

BACKGROUND

Current methods to measure intragastric pH in horses have limitations. A wireless capsule has been designed for continuous esophageal pH monitoring in humans.

OBJECTIVES

To (1) determine the feasibility and describe the methodology of measuring intragastric pH wirelessly in horses; and (2) determine attachment duration of the capsules.

ANIMALS

Eleven healthy adult horses.

METHODS

Capsules were attached to squamous and glandular gastric mucosa under gastroscopic guidance, using suture loops and 1 to 4 hemostasis clips. pH was continuously recorded using a wireless recorder in both fed and fasted states. Gastroscopy was performed daily to assess capsule attachment and any mucosal damage. Data were analyzed using commercially available software. Values are reported as median (interquartile range).

RESULTS

Capsules were successfully placed and data obtained in squamous (n = 11) and glandular (n = 7) regions. The overall duration of squamous capsule attachment was 27 hours (15-32); 1 clip (n = 4) was 15 hours (11-20), 2 clips (n = 2) was 20 hours (16-23), 3 clips (n = 4) was 32 hours (30-32), and 4 clips (n = 1) was 33 hours. The overall duration of glandular capsule attachment was 10 hours (8-21); 1 clip (n = 2) was 11 hours (10-13), 2 clips (n = 2) was 19 hours (14-23), 3 clips (n = 2) was 7 hours (7-8), and 4 clips (n = 1) was 158 hours. There was no substantial damage to the gastric mucosa as a consequence of attachment.

CONCLUSIONS AND CLINICAL IMPORTANCE

This novel technique enables the wireless measurement of intragastric pH in horses at known locations under fed and fasted conditions, providing a viable alternative for continuous monitoring in both research and clinical scenarios.

A Bimodal Low-Power Transceiver featuring a Ring Oscillator-based Transmitter and Magnetic Field-based Receiver for Insertable Smart Pills

This paper presents a novel bimodal, low-power, mm-scale transceiver for insertable smart pills. The proposed PA-less, 915 MHz uplink transmitter (TX) incorporates an 1.21.2 mm² on-chip, non-resonated antenna as part of a current-starved ring oscillator (RO) and directly transmits data by turning the RO on/off. This RO-based uplink TX is implemented in 180 nm CMOS along with a power management unit, which generates all internal reference voltages and supplies from a single battery. The uplink TX achieves a data rate of 33 Mb/s and consumes 210 μW, resulting in an energy efficiency of 6.4 pJ/bit. The orientation-insensitive magnetic field-based downlink receiver (RX) is implemented with an external 3-D magnetic sensor, achieves 0.02 kb/s of data rate limited by our measurement setup, and consumes 270 μW. Wireless measurements in saline over 150 cm and prototype of the 3.213.62.3 mm³ insertable pill are presented.

Low-dose PPI to prevent bleeding after ESD: A multicenter randomized controlled study

BACKGROUND

Although proton pump inhibitors (PPIs) are widely used in the prevention of gastric bleeding caused by endoscopic submucosal dissection (ESD), there is no consensus on the optimal regimen for these patients. Therefore, we aim to investigate whether intermittent use of low-dose PPI is sufficient to prevent post-ESD bleeding.

METHODS

This multicenter, non-inferiority, randomized controlled trial was conducted at 9 hospitals in China. Consecutive eligible patients with a diagnosis of gastric mucosal lesions after ESD treatment were randomly assigned (1:1) to receive either intermittent low-dose or continuous high-dose PPIs treatment. After three days, all patients administered orally esomeprazole 40 mg once a day for 8 weeks. The primary endpoint was post-ESD bleeding within 7 days. Analysis was done according to the intention-to-treat principle with the non-inferiority margin (Δ) of 5%.

RESULTS

526 consecutive patients were assessed for eligibility from 30 September 2017 to 30 July 2019, of whom 414 were randomly assigned to low-dose (n = 209) or high-dose (n = 205) esomeprazole treatment group without dropouts within7 days. The total post-ESD bleeding is occurred in 13 (6.2 %, 95 % CI 3.3-9.6) of 209 within 7 days in the intermittent low-dose group, and 12 (5.9 %, 95 % CI 2.9-9.3) of 205 in the continuous high-dose group. The absolute risk reduction (ARR) was 0.4 % (-4.2, 4.9). One month after ESD, There are 44 patients (21.1 %, 95 % CI 15.8, 26.8) and 39 patients (19.0 % 95 % CI 13.7, 24.4) in scar stage respectively in low-dose group and high-dose group (P = 0.875).The hospital costs in the low-dose PPI group was lower than high -dose group (P = 0.005).

CONCLUSION

The intermittent use of low-dose PPIs is sufficient to prevent post-ESD bleeding. It might be applied in clinical practice to prevent post-ESD bleeding and reduce the costs related to PPIs.

In Situ Gastric pH Imaging with Hydrogel Capsule Isolated Paramagnetic Metallo-albumin Complexes

Abnormal gastric pH (pH > 3) has instructive significance for early diagnosis of various diseases, including cancer. However, for low patient compliance, limited penetration depth, high dependence on physiological function or unsafety issue, in situ noninvasive monitoring gastric pH is challenged. Herein, we developed a hydrogel capsule isolated human serum albumin-manganese complex (HSA-Mn) for in situ magnetic resonance imaging (MRI) gastric pH monitoring for the first time. In this strategy, the rotation motion restriction of Mn²⁺ after binding to HSA significantly increased the R₁ (longitudinal relaxation rate) signal, and its high correlation with protonation imparted the HSA-Mn system sensitive responsiveness to varying pH (R₁(pH 7)/R₁(pH 1) = 8.2). Moreover, a screw jointed hydrogel capsule with signal confinement and internal standard abilities was designed. Such a nanoporous hydrogel capsule with size selectivity to surrounding molecules enabled a stable and sensitive response to different pH simulated gastric fluid within 0.5 h. In addition, with the unique structural outline and stable MRI characteristics, the capsule could also work as an internal standard, which facilitates the collection of signals and trace of the capsule in vivo. Through validating in a rabbit model, the precise abnormal gastric pH recognition capacity of the HSA-Mn hydrogel capsule was amply confirmed. Hence, the hydrogel capsule isolated HSA-Mn system strategy with great biocompatibility could be expected to be a potent tool for in situ anti-disturbance MRI of gastric pH in future clinical application.

A Millimeter-Scale Crystal-Less MICS Transceiver for Insertable Smart Pills

This paper presents a millimeter-scale crystal-less wireless transceiver for volume-constrained insertable pills. Operating in the 402-405 MHz medical implant communication service (MICS) band, the phase-tracking receiver-based over-the-air carrier recovery has a ±160 ppm coverage. A fully integrated adaptive antenna impedance matching solution is proposed to calibrate the antenna impedance variation inside the body. A tunable matching network (TMN) with single inductor performs impedance matching for both transmitter (TX) and receiver (RX) and TX/RX mode switching. To dynamically calibrate the antenna impedance variation over different locations and diet conditions, a loop-back power detector using self-mixing is adopted, which expands the power contour up to 4.8 VSWR. The transceiver is implemented in a 40-nm CMOS technology, occupying 2 mm² die area. The transceiver chip and a miniature antenna are integrated in a 3.5 × 15 mm² area prototype wireless module. It has a receiver sensitivity of -90 dBm at 200 kbps data rate and delivers up to - 25 dBm EIRP in the wireless measurement with a liquid phantom.

Large Buffering Effect of the Duodenal Bulb in Duodenal Switch: a Wireless pH-Metric Study

Introduction

Bariatric procedures result in massive weight loss, however, not without side effects. Gastric acid is known to cause marginal ulcers, situated in the small bowel just distal to the upper anastomosis. We have used the wireless BRAVO™ system to study the buffering effect of the duodenal bulb in duodenal switch (DS), a procedure in which the gastric sleeve produces a substantial amount of acid.

Methods

We placed a pre- and a postpyloric pH capsule in 15 DS-patients (seven men, 44 years, BMI 33) under endoscopic guidance and verified the correct location by fluoroscopy. Patients were asked to eat and drink at their leisure, and to register their meals for the next 24 h.

Results

All capsules but one could be successfully placed, without complications. Total registration time was 17.2 (1.3–24) hours prepyloric and 23.1 (1.2–24) hours postpyloric, with a corresponding pH of 2.66 (1.74–5.81) and 5.79 (4.75–7.58), p < 0.01. The difference in pH between the two locations was reduced from 3.55 before meals to 1.82 during meals, p < 0.01. Percentage of time with pH < 4 was 70.0 (19.9–92.0) and 13.0 (0.0–34.6) pre and postpylorically, demonstrating a large buffering effect.

Conclusion

By this wireless pH-metric technique, we could demonstrate that the duodenal bulb had a large buffering effect, thus counteracting the large amount of gastric acid passing into the small bowel after duodenal switch. This physiologic effect could explain the low incidence of stomal ulcers.

Functional Photoacoustic Imaging of Gastric Acid Secretion Using pH-Responsive Polyaniline Nanoprobes

A stomach functional imaging technique based on photoacoustics achieves noninvasive gastric acid secretory assessment utilizing pH-responsive polyaniline nanoprobes. A testing protocol mimicking clinical practice is established using a mouse model. After imaging, the nanoprobes are excreted outside the body without inducing systematic toxicity. Further optimization and translation of this technology can help alleviate patients' suffering and side effects.

Ovine rumen papillae biopsy via oral endoscopy; a rapid and repeatable method for serial sampling

AIMS: To explore and validate the utility of rumen endoscopy for collection of rumen papillae for gene expression measurement.

METHODS: Four adult Coopworth ewes were fasted for either 4 or 24 hours. Animals were sedated, placed in a dorsally recumbent position at 45 degrees with the head upright, and an endoscope inserted via a tube inserted into the mouth. Biopsies of rumen papillae were taken from the ventral surface of the rumen atrium under visual guidance. Two biopsies were collected from one of the animals that had been fasted for 4 hours, and three from one of the animals that had been fasted for 24 hours. Video of the rumen atrium and reticulum was also collected. The animals recovered uneventfully. Biopsies were subsequently used for extraction and sequencing of mRNA.

RESULTS: The ventral surface of the rumen atrium was accessible after 4 hours off pasture, but a larger region was accessible after 24 hours of fasting. Sedation allowed access for endoscope use for around 5 to 10 minutes after which increased saliva flow was noted. Rumen papillae biopsies were easily collected, with samples from a variety of sites collected in the ∼10 minute time window. High quality RNA was obtained for stranded mRNA sequencing. Of the resulting reads, 69–70% mapped uniquely to version 3.1 of the ovine genome, and 48–49% to a known gene. The rumen mRNA profiles were consistent with a previously reported study.

CONCLUSIONS: This method for obtaining rumenal tissue was found to be rapid and resulted in no apparent short or long term effects on the animal. High quality RNA was successfully extracted and amplified from the rumen papillae biopsies, indicating that this technique could be used for future gene expression studies. The use of rumen endoscopy could be extended to collection of a variety of rumen and reticulum anatomical measurements and deposition and retrieval of small sensors from the rumen. Rumen endoscopy offers an attractive and cost effective approach to repeated rumen biopsies compared with serial slaughter or use of cannulated animals.

Gastric Hypersecretory States: Investigation and Management

Hypersecretory conditions affecting the stomach account for significant morbidity and mortality manifested in some cases with peptic ulcer, gastrointestinal hemorrhage, and/or gastroesophageal reflux disease (GERD). The diagnosis of gastric acid hypersecretory states can be challenging and relies on the use of quantitative assays to measure gastric acid secretion and serum gastrin. The most common etiology for hypergastrinemia is the use of potent gastric acid inhibitors such as the proton pump inhibitors. The differential diagnosis of this condition is of critical importance, and will dictate management decisions. Conditions such as atrophic gastritis are relatively benign and can lead to hypergastrinemia without the presence of gastric acid hypersecretion. Zollinger-Ellison syndrome, on the other hand, causes hypergastrinemia with profound gastric acid hypersecretion [1]. More common causes of hypergastrinemia include gastric outlet obstruction, ileus, and chronic renal failure [2]. In most cases, proton pump inhibitors will be used to manage these conditions. In some instances, surgical therapy may be required. This chapter will review the important clinical causes of gastric acid hypersecretion and provide insights to the best medical management options to better care for patients with these disorders.

Engineering of Kuma030: A Gliadin Peptidase That Rapidly Degrades Immunogenic Gliadin Peptides in Gastric Conditions

Celiac disease is characterized by intestinal inflammation triggered by gliadin, a component of dietary gluten. Oral administration of proteases that can rapidly degrade gliadin in the gastric compartment has been proposed as a treatment for celiac disease; however, no protease has been shown to specifically reduce the immunogenic gliadin content, in gastric conditions, to below the threshold shown to be toxic for celiac patients. Here, we used the Rosetta Molecular Modeling Suite to redesign the active site of the acid-active gliadin endopeptidase KumaMax. The resulting protease, Kuma030, specifically recognizes tripeptide sequences that are found throughout the immunogenic regions of gliadin, as well as in homologous proteins in barley and rye. Indeed, treatment of gliadin with Kuma030 eliminates the ability of gliadin to stimulate a T cell response. Kuma030 is capable of degrading >99% of the immunogenic gliadin fraction in laboratory-simulated gastric digestions within physiologically relevant time frames, to a level below the toxic threshold for celiac patients, suggesting great potential for this enzyme as an oral therapeutic for celiac disease.

Evaluation of the effect of orally administered acid suppressants on intragastric pH in cats

Background

Acid suppressant drugs are a mainstay of treatment for cats with gastrointestinal erosion and ulceration. However, clinical studies have not been performed to compare the efficacy of commonly PO administered acid suppressants in cats.

Hypothesis/Objectives

To compare the effect of PO administered famotidine, fractionated omeprazole tablet (fOT), and omeprazole reformulated paste (ORP) on intragastric pH in cats. We hypothesized that both omeprazole formulations would be superior to famotidine and placebo.

Animals

Six healthy adult DSH colony cats.

Methods

Utilizing a randomized, 4‐way crossover design, cats received 0.88–1.26 mg/kg PO q12h fOT, ORP, famotidine, and placebo (lactose capsules). Intragastric pH monitoring was used to continuously record intragastric pH for 96 hours beginning on day 4 of treatment. Plasma omeprazole concentrations at steady state (day 7) were determined by high performance liquid chromatography (HPLC) with ultraviolet detection. Mean percentage time that intragastric pH was ≥3 and ≥4 were compared among groups using ANOVA with a posthoc Tukey‐Kramer test (α = 0.05).

Results

The mean percentage time ± SD that intragastric pH was ≥3 was 68.4 ± 35.0% for fOT, 73.9 ± 23.2% for ORP, 42.8 ± 18.6% for famotidine, and 16.0 ± 14.2% for placebo. Mean ± SD plasma omeprazole concentrations were similar in cats receiving fOT compared to those receiving ORP and in a range associated with acid suppression reported in other studies.

Conclusions and Clinical Importance

These results suggest that both omeprazole formulations provide superior acid suppression in cats compared to famotidine or placebo. Fractionated enteric‐coated OT is an effective acid suppressant despite disruption of the enteric coating.

Preprocedural rabeprazole treatment before endoscopic submucosal dissection for gastric neoplasms

BACKGROUND

The maximal effect of proton pump inhibitors (PPI) is reported to take 5 days. However, most current protocols start PPI on the day of gastric endoscopic submucosal dissection (ESD).

AIMS

We aimed to evaluate the benefit of 5 days pretreatment with oral PPI before ESD to prevent bleeding.

METHODS

This was a prospective randomized controlled trial. Patients were administered oral rabeprazole 20 mg or placebo twice daily for 5 days before ESD. Intravenous pantoprazole 40 mg was administered 2 h before ESD and at postprocedure day 1, and then oral rabeprazole 20 mg was administered once daily. Follow-up endoscopy was performed on days 1 and 30. Forty-eight-hour measurement of intragastric pH was performed in 26 patients. The primary endpoint was major bleeding related to ESD.

RESULTS

One-hundred and twenty patients were enrolled. Of these, 45 in the pretreatment and 53 in the placebo group were analyzed. Each group had three cases of major bleeding. There were no significant differences in the ulcer healing rate. Intragastric pH percentage times greater than 4, 5, and 6 were 86.61 ± 19.45 %, 83.30 ± 22.06 %, and 76.86 ± 25.35 %, respectively, in the pretreatment and 85.54 ± 19.45 %, 84.08 ± 27.11 %, and 81.53 ± 27.81 %, respectively, in the placebo group, without significant differences.

CONCLUSIONS

Preprocedural administration of rabeprazole offers no additional benefit over postprocedural administration alone in preventing major bleeding after gastric ESD.

A new method for determining gastric acid output using a wireless pH-sensing capsule

BACKGROUND

Gastro-oesophageal reflux disease (GERD) and gastric acid hypersecretion respond well to suppression of gastric acid secretion. However, clinical management and research in diseases of acid secretion have been hindered by the lack of a non-invasive, accurate and reproducible tool to measure gastric acid output (GAO). Thus, symptoms or, in refractory cases, invasive testing may guide acid suppression therapy.

AIM

To present and validate a novel, non-invasive method of GAO analysis in healthy subjects using a wireless pH sensor, SmartPill (SP) (SmartPill Corporation, Buffalo, NY, USA).

METHODS

Twenty healthy subjects underwent conventional GAO studies with a nasogastric tube. Variables impacting liquid meal-stimulated GAO analysis were assessed by modelling and in vitro verification. Buffering capacity of Ensure Plus was empirically determined. SP GAO was calculated using the rate of acidification of the Ensure Plus meal. Gastric emptying scintigraphy and GAO studies with radiolabelled Ensure Plus and SP assessed emptying time, acidification rate and mixing. Twelve subjects had a second SP GAO study to assess reproducibility.

RESULTS

Meal-stimulated SP GAO analysis was dependent on acid secretion rate and meal-buffering capacity, but not on gastric emptying time. On repeated studies, SP GAO strongly correlated with conventional basal acid output (BAO) (r = 0.51, P = 0.02), maximal acid output (MAO) (r = 0.72, P = 0.0004) and peak acid output (PAO) (r = 0.60, P = 0.006). The SP sampled the stomach well during meal acidification.

CONCLUSIONS

SP GAO analysis is a non-invasive, accurate and reproducible method for the quantitative measurement of GAO in healthy subjects. SP GAO analysis could facilitate research and clinical management of GERD and other disorders of gastric acid secretion.

Traditional vs wireless intragastric pH monitoring: are the two techniques comparable?

BACKGROUND

Few data are available comparing intragastric pH measured with the traditional catheter-based and the more recent wireless system (Bravo), and also comparing intraesophageal and intragastric pH during reflux events. Aims of our study were to elucidate these points.

METHODS

Eleven subjects with functional dyspepsia underwent placement of a Bravo capsule 9 cm below the squamo-columnar junction (SCJ) and of a dual-electrode catheter, so that the distal electrode was located 9 cm below and the proximal one 6 cm above the SCJ.

KEY RESULTS

The wireless system showed lower intragastric pH than the traditional catheter in the postprandial period (median 2.2 wireless vs 2.7 catheter, P < 0.05) but not in the whole 24 h. Moreover, during the 24 h, minimum intraesophageal pH during reflux events was lower than the simultaneous pH in the gastric body recorded using the catheter (2.2 vs 2.4, P < 0.01) and in the postprandial period lower than the one recorded using both techniques (2.3 vs 2.8 wireless and 3.2 catheter, P < 0.001).

CONCLUSIONS & INFERENCES

(i) after meals, in the 1st 2 h postprandial pH in the gastric body is significantly lower when measured with the wireless capsule than with the traditional catheter, presumably because of less buffering by food in proximity of the mucosa, (ii) during reflux events intraesophageal pH is lower than pH in the gastric body, in accordance with the notion of greater intragastric acidity in the subcardial region.

Persistent gastric colonization with Burkholderia pseudomallei and dissemination from the gastrointestinal tract following mucosal inoculation of mice

Melioidosis is a disease of humans caused by opportunistic infection with the soil and water bacterium Burkholderia pseudomallei. Melioidosis can manifest as an acute, overwhelming infection or as a chronic, recurrent infection. At present, it is not clear where B. pseudomallei resides in the mammalian host during the chronic, recurrent phase of infection. To address this question, we developed a mouse low-dose mucosal challenge model of chronic B. pseudomallei infection and investigated sites of bacterial persistence over 60 days. Sensitive culture techniques and selective media were used to quantitate bacterial burden in major organs, including the gastrointestinal (GI) tract. We found that the GI tract was the primary site of bacterial persistence during the chronic infection phase, and was the only site from which the organism could be consistently cultured during a 60-day infection period. The organism could be repeatedly recovered from all levels of the GI tract, and chronic infection was accompanied by sustained low-level fecal shedding. The stomach was identified as the primary site of GI colonization as determined by fluorescent in situ hybridization. Organisms in the stomach were associated with the gastric mucosal surface, and the propensity to colonize the gastric mucosa was observed with 4 different B. pseudomallei isolates. In contrast, B. pseudomallei organisms were present at low numbers within luminal contents in the small and large intestine and cecum relative to the stomach. Notably, inflammatory lesions were not detected in any GI tissue examined in chronically-infected mice. Only low-dose oral or intranasal inoculation led to GI colonization and development of chronic infection of the spleen and liver. Thus, we concluded that in a mouse model of melioidosis B. pseudomallei preferentially colonizes the stomach following oral inoculation, and that the chronically colonized GI tract likely serves as a reservoir for dissemination of infection to extra-intestinal sites.

Review article: methods of measuring gastric acid secretion

BACKGROUND

Gastric acid has an important pathophysiological role in human beings. Numerous methods have been evaluated over the years in an attempt to measure gastric acid and stomach acidity, to study the role of gastric acid in gastrointestinal diseases in humans and to evaluate the effects of acid suppressing drugs.

AIM

To review methods that have been used to measure gastric acid and gastric acidity.

METHODS

Searches of the electronic databases PUBMED, MEDLINE and EMBASE, were performed with articles restricted to English language and human subjects. References were also identified from the bibliographies of selected articles.

RESULTS

Methods for measuring gastric acid include both invasive and non-invasive techniques. Invasive tests include the conventional gastric acid aspiration tests, gastric pH measurement techniques and endoscopic methods. Non-invasive methods use urinary analysis, breath analysis, serum pepsinogens assay, scintigraphic techniques, impedence tomography and alkaline tide for measurement of gastric acid.

CONCLUSIONS

Several methods of measuring gastric acid exist. Invasive tube tests are uncomfortable and time consuming, whereas most of the non-invasive methods are at best semiquantitative and useful in detecting low or absent acid secretion. Further attempts to explore new methods for measuring gastric acid are therefore warranted.

Usefulness of catheterless radiotelemetry pH monitoring system to examine the relationship between duodenal acidity and upper gastrointestinal symptoms

BACKGROUND AND AIM

To clarify the usefulness of a newly designed method for measuring intraduodenal pH to examine the relationship between duodenal acidity and upper gastrointestinal symptoms during intragastric acid infusion.

METHODS

The study subjects were six healthy volunteers. A Bravo pH capsule with thread fixed to the gastric wall was endoscopically introduced into the second portion of the duodenum, and intraduodenal acidity was measured during intragastric infusion of 300 mL of 0.1 mol/L hydrochloric acid or pure water through an elemental diet tube. The severity of several upper gastrointestinal symptoms were assessed by using a 10-cm visual analogue scale every 2 min for up to 30 min, and the area under the severity scale-time curve (cm×min.) were calculated.

RESULTS

The percentage time during 30 min when the intraduodenal pH was <4.0 and was significantly greater than during water infusion (61.4±6.1% vs 24.8±6.5%). Several upper gastrointestinal symptoms were observed during acid infusion (acid vs water epigastric heaviness, 29.1±12.0 vs 2.7±1.4; dull epigastric pain, 8.8±4.9 vs 0.7±0.7 cm×min/30 min). Intraduodenal pH below 4.0 was correlated with the severity of dull pain in the stomach (R(2)=0.342, P=0.044).

CONCLUSION

The newly designed intraduodenal pH monitoring by using catheterless radiotelemetry system is useful to examine the relationship between duodenal acidity and upper gastrointestinal symptoms.

Efficacy of oral famotidine and 2 omeprazole formulations for the control of intragastric pH in dogs

BACKGROUND

Little is known about the efficacy of commonly used acid suppressants on intragastric pH in dogs.

OBJECTIVE

To compare the effect of oral famotidine, 2 formulations of omeprazole, and placebo on intragastric pH in dogs with a catheter-free, continuous pH monitoring system.

ANIMALS

Six healthy adult mixed-breed colony dogs.

METHODS

Utilizing a randomized, 4-way cross over, open-label study, dogs were administered famotidine PO (1.0-1.3 mg/kg q12h), omeprazole tablet (1.5-2.6 mg/kg q24h), omeprazole reformulated paste (RP) (Gastrogard, 1.5-2.6 mg/kg q24h), and placebo for 7 days followed by a 10-day washout period. Radiotelemetric pH capsules were placed with gastroscopy assistance to continuously record intragastric pH for 4 days (days 4-7 of dosing). The percentage of time that intragastric pH was ≥3 and ≥4 was compared among treatment groups using repeated measures of analysis of variance. Tukey's Studentized range test was used to determine which groups were different with α= 0.05.

RESULTS

Mean ± SD percent time intragastric pH was ≥3 and ≥4 was 22 ± 8% and 14 ± 6% for famotidine, 63 ± 14% and 52 ± 17% for omeprazole tablet, 54 ± 17% and 44 ± 18% for omeprazole RP, and 6 ± 6% and 5 ± 5% for placebo. Both omeprazole formulations significantly increased intragastric pH compared with famotidine and placebo, but omeprazole tablet and RP was not significantly different from each other.

CONCLUSION

Oral omeprazole tablet and RP provide superior gastric acid suppression to famotidine, and should therefore be considered more effective for the treatment of acid related disorders in dogs.

Oral buffered esomeprazole is superior to i.v. pantoprazole for rapid rise of intragastric pH: a wireless pH metry analysis

BACKGROUND AND AIMS

A pH of more than 6 is required for clot stability and hemostasis. Intravenous proton pump inhibitors have a rapid onset of action compared to oral and have been preferred for management of non-variceal bleeding. Intravenous pantoprazole has been used extensively. Buffered esomeprazole (BE) is an oral preparation consisting of an inner core of non-enteric-coated esomeprazole with a shell of sodium bicarbonate. The buffer protects against acid degradation of esomeprazole in addition to immediate antacid action. The aim of this study was to assess the efficacy of BE for raising and maintaining an intragastric pH of more than 6 in comparison to i.v. pantoprazole in equivalent dosing.

METHODS

A randomized two-way cross-over study was conducted. Ten healthy volunteers were randomized to twice daily BE 40 mg or pantoprazole 40 mg i.v. bolus. Intragastric pH was measured with a wireless pH radiotelemetry capsule (Bravo, Medtronic). A 2-week washout period was given between doses.

RESULTS

BE achieved a steady pH of more than 6 in a median time of 2 min (range 1-5 min) after the first dose. The mean % time that intragastric pH was more than 6.0 for BE was 96%, and 90% of the 24-h period compared to pantoprazole (47% and 18%), P = 0.000. A median pH (interquartile range) for the BE group was 6.2 (6.175-6.2) which was higher than i.v. pantoprazole 4.60 (4.5-5.0) (P = 0.005).

CONCLUSION

BE achieves and maintains a pH of more than 6 within minutes of administration. It was significantly superior to i.v. pantoprazole in equivalent dosing. This finding could have implications in the management of non-variceal bleed where a rapid and sustained pH of more than 6 is desirable.