pH Monitoring Research Articles

The impact of gastroesophageal reflux disease on upper esophageal sphincter function: Insights from PH impedance and high-resolution manometry.

Lower esophageal sphincter (LES) pathophysiology has been established in gastroesophageal reflux disease (GERD); however, less is understood regarding the role the upper esophageal sphincter (UES) plays in preventing laryngopharynphageal reflux. Sustained UES basal pressure prevents reflux into the pharynx while allowing relaxation during ingestion. We investigate whether GERD influences UES function via HRM and pH Impedance testing. A retrospective analysis of 318 patients who underwent high-resolution manometry with trans-nasally placed manometric catheter and 24-h multichannel intraluminal impedance pH monitoring. One hundred and forty-seven patients met Lyon consensus criteria for GERD based on acid exposure time >6%. The most common chief concern was heartburn or reflux, present in 59% of these patients. Upper esophageal sphincter basal and residual pressures were not significantly different between patients with GERD when compared to those without GERD, including a subanalysis of patients with extraesophageal symptoms. The LES basal and residual pressures, DCI and MNBI are statistically lower in patients with pathologic GERD. HRM and pH Impedance testing demonstrates no difference in UES basal and residual pressures based on pH diagnosis of GERD. We redemonstrate the association with hypotonic LES, diminished DCI and MNBI with GERD.

Resourceful exploitation of sedimentary clay: Designing a dual-chambered borosilicate glass reactor system for the efficient treatment of malachite green and phenol through SCRT adsorption and 5%Fe@SRCT catalysis via CWPO, with evaluation of seed germination and fish survival.

This study presents an innovative double-walled borosilicate glass reactor system for the efficient treatment of liquid and gaseous wastewater. This reactor system allows precise temperature control, continuous pH monitoring, and controlled dosing of reagents to optimize reaction conditions. Detailed characterization was carried out by X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), BET (specific surface area) analysis, point of zero charge (PZC), and scanning electron microscopy (SEM) for the SCR, SCRT, and 5%Fe@SCRT materials. For Malachite Green adsorption, SRCT demonstrated a maximum adsorption capacity of 39.78 ±0.5mg/g using the Langmuir isotherm model and followed pseudo-second-order kinetics. Optimum conditions for adsorption were found to be: an initial concentration of 50 ppm, an adsorbent dosage of 1g/l, a pH of 8.5, and a temperature of 50°C. For the catalytic oxidation of phenol, 5%Fe@SRCT achieved a remarkable removal rate of 99.9±0.1% under optimum conditions (50 ppm phenol, 1g/l catalyst dosage, pH3.5, H2O2 concentration 8.7mM, and temperature 70°C). Intermediates identified during the reaction included hydroquinone, benzoquinone, catechol, and resorcinol, with degradation occurring over a 60-minute reaction period. The 5%Fe@SCRT material showed excellent reusability in the removal of phenol by catalytic oxidation, with no significant loss of efficiency over three cycles, while the SRCT underwent three cycles of regeneration for the adsorption of Malachite Green. Scavenger tests confirmed the involvement of hydroxyl radicals in the catalytic oxidation process. In addition, fish survival tests after catalytic oxidation of phenol by 5%Fe@SRCT showed no impact on fish, underlining the environmental safety of this process. In addition, germination tests after decolorization of MG by SRCT demonstrated a good effect with no negative impact, reinforcing the ecological value of this innovative technology. These results highlight the innovative use of SCRT and 5%Fe@SCRT as versatile materials for environmental remediation, exploiting their effective adsorption capacities and efficient catalytic oxidation performance within the proposed double-walled borosilicate glass reactor system. PRACTITIONER POINTS: The study demonstrates the effectiveness of an innovative reactor system employing SRCT adsorbent and Fe@SRCT catalyst for efficient removal of malachite green and phenol from wastewater. Environmental impact assessment, including seed germination and fish survival evaluation, validates the method's eco-friendly potential. Implementation of this approach could significantly contribute to sustainable water treatment practices.

Piloting an intraoral pH device to track gastroesophageal reflux in adults

This study evaluated in vivo, an intraoral device against the gold standard esophageal device for gastroesophageal reflux disease (GERD) monitoring. Subjects scheduled for a catheter-based esophageal pH/impedance testing at a gastroenterology clinic were recruited. They were screened using the GerdQ questionnaire, demographics and dental conditions recorded. A prototype intraoral device, consisting of a Bravo™ capsule embedded in an Essix-style retainer fabricated for each subject, monitored intraoral pH. Concurrently, subjects underwent 24-h esophageal pH-impedance monitoring. A self-administered survey elicited the comfort and acceptance of both devices. The study recruited ten adult subjects (23 to 60-years-old) with a median GerdQ score of 9.5 corresponding to a 79% likelihood of GERD. Subjects with severe dental erosion had significantly (p < 0.05) higher acid exposure time and more non-meal reflux events. No adverse events were associated with the intraoral device while one was recorded for the esophageal device. The intraoral device was significantly more comfortable to place, more comfortable to wear, and interfered less with daily routine compared to the esophageal device. Accuracy of the intraoral device ranged between 86.15% and 37.82%. Being more tolerable than traditional esophageal pH monitoring, intraoral pH monitoring may be a useful adjunct for the diagnosis and management of GERD.

Association between Oral Microbiome and Gastroesophageal Reflux Severity.

Background/Objectives: Gastroesophageal reflux disease (GORD) is caused by gastric contents refluxing back into the oesophagus and oral cavity. It can lead to injuries to the mucosa in the form of erosion and ulcers. Our past research have shown acid reflux severity and disease progression is associated with alternations in the microbiota of the distal oesophagus. The aim of this study was to explore whether changes in the oral microbiota occurred in GORD patients and establish any associations with reflux severity. Methods: Fresh mouthwash samples were collected from 58 patients experiencing reflux symptoms referred for 24 h pH monitoring. The participants were categorised into three groups based on their DeMeester scores: Normal (<14.72), Mild (14.2-50), and Moderate/severe (>51). Microorganism identity and diversity were generated using hypervariable tag sequencing and analysing the V1-V3 region of the 16S rRNA gene. Results: No differences in microbiota diversity were found in oral microbiota between groups using the Chiao1 diversity index and Shannon diversity index. Microbiota in the Mild group showed reductions in Rothia dentocariosa and Lautropia, while Moryella and Clostridiales_1 were increased compared with the Normal group. In the Moderate/severe group, the abundance of Rothia aeria was reduced compared with the Normal group, while Schwartzia, Rs_045, Paludibacter, S. satelles, Treponema, and T. socranskii all had increased abundance. The abundance of Prevotella pallens was higher in the Mild group compared with Moderate/severe, while S. satelles and Paludibacter abundances were lower. Conclusions: Our study shows the oral microbiome show significant differences between acid reflux severity groups, as categorised by DeMeester score.

Redox homeostasis and pH monitoring: a step forward to personalized medicine and dermatology

Skin is continually subjected to various environmental stressors, such as pollution, UV rays, and other oxidative damage factors. It is obligatory to ascertain the exact importance of redox status and ROS indicators, which may be assessed in diverse physiological fluids and tissues. Reactive oxygen species (ROS) can cause lipid peroxidation, which can compromise the integrity and functionality of skin cells by degrading membrane lipids. This may compromise the skin barrier, making the skin more prone to infections and environmental irritants, increasing water loss and dryness. Collagen in the dermis can covalently link to malondialdehyde (MDA), a byproduct of lipid peroxidation generated by oxidatively damaged skin lipids, to form MDA-collagen adducts. Several types of skin cancer are associated with a heightened vulnerability of DNA purine and pyrimidine bases to oxidative damage and altered DNA repair capacity (DRC). Damage from ROS may cause hyaluronate to become less viscous, which increases its susceptibility to degradation. Elastin hydrodynamic radius decreased the rate of self-assembly in response to ROS. Alterations in redox homeostasis can lead to various diseases and conditions, including vitiligo, actinic keratosis, psoriasis, contact dermatitis, systemic sclerosis, the onset of wrinkles, and skin aging. The most recent formulations' capacity to improve pH and Redox simultaneously can be attained by carefully selecting proposed antioxidant formulations. The combination of modern preparations is currently available and should be used in accordance with the suggested guidelines.

Skin-attachable Tb-MOF ratio fluorescent sensor for real-time detection of human sweat pH

The pH of human sweat is highly related with a variety of diseases, whereas the monitoring of sweat pH still remains challenging for ordinary families. In this study, we developed a novel dual-emission Tb-MOF using DPA as the ligand and further designed and constructed a skin-attachable Tb-MOF ratio fluorescent sensor for real-time detection of human sweat pH. With the increased concentration of H+, the interaction of H+ with carbonyl organic ligand leads to the collapse of the Tb-MOF crystal structure, resulting in the interruption of antenna effect, and correspondingly increasing the emission of the ligand at 380 nm and decreasing the emission of the central ion Tb3+ at 544 nm. This Tb-MOF nanoprobe has a good linear response in the pH range of 4.12–7.05 (R2 = 0.9914) with excellent anti-interference ability. Based on the merits of fast pH response and high sensitivity, the nanoprobe was further used to prepare flexible wearable sensor. The wearable sensor can detect pH in the linear range of 3.50–6.70, which covers the pH range of normal human sweat (4.50–6.50). Subsequently, the storage stability and detection accuracy of the sensors were evaluated. Finally, the sensor has been successfully applied for the detection of pH in actual sweat samples from 21 volunteer and the real-time monitoring of pH variation during movement processing. This skin-attachable Tb-MOF sensor, with the advantages of low cost, visible color change and long shelf-life, is appealing for sweat pH monitoring especially for ordinary families.

A Chromium-Based magnetic resonance probe for in situ gastric pH imaging

Effective monitoring of gastric fluid pH is crucial for diagnosing gastric diseases and evaluating anti-gastric-acid therapies. The invasiveness and low patient compliance with traditional gastric fluid aspiration methods highlight the need of a non-invasive, real-time technique for in situ gastric pH monitoring. This study introduces a novel chromium (Cr)-based magnetic resonance probe, Cr(OH)3@HSA, specifically designed for pH-sensitive gastric imaging. Synthesized via an albumin-mediated biomimetic mineralization process, Cr(OH)3@HSA possesses an amorphous structure that facilitates the sensitive release of paramagnetic Cr(III) ions in acidic environments. This release substantially decreases the longitudinal relaxation time of surrounding hydrogen protons, as demonstrated by an 18.29-fold increase in the longitudinal relaxation rate from pH 6.5 to pH 1.0. In vivo experiments show that Cr(OH)3@HSA accurately detects abnormal gastric pH levels and evaluates the efficacy of gastric antiacids, surpassing the performance of the conventional “always-on” contrast agent, Magnevist®. Notably, our research reveals that chromium picolinate, a common dietary supplement for diabetes, generates a “turn-on” signal in the gastrointestinal tract, suggesting potential MR signal interference in diabetic patients. Consequently, we recommend that diabetic patients avoid chromium-based dietary supplements prior to MRI procedures to prevent Cr(III)-induced signal alterations.

Flexible Multimodal Sensors Enhanced by Electrospun Lead-Free Perovskite and PVDF-HFP Composite Form-Stable Mesh Membranes for In Situ Plant Monitoring.

The pH and humidity of the crop environment are essential indicators for monitoring crop growth status. This study reports a lead-free perovskite/polyvinylidene fluoride-hexafluoropropylene composite (LPPC) to enhance the stability and reliability of in situ plant pH and humidity monitoring. The mesh composite membrane of LPPC illustrates a hydrophobic contact angle of 101.982°, a tensile strain of 800%, and an opposing surface potential of less than -184.9 mV, which ensures fast response, high sensitivity, and stability of the sensor during long-term plant monitoring. The LPPC-coated pH electrode possesses a sensitivity of -63.90 mV/pH, which provides a fast response within 5 s and is inert to environmental temperature interference. The LPPC-coated humidity sensor obtains a sensitivity of -145.7 Ω/% RH, responds in 28 s, and works well under varying light conditions. The flexible multimodal sensor coated with an LPPC membrane completed real-time in situ monitoring of soilless strawberries for 17 consecutive days. Satisfactory consistency and accuracy performance are observed. The study provides a simple solution for developing reliable, flexible wearable multiparameter sensors for in situ monitoring of multiple parameters of crop environments.

Remote Water Quality Monitoring System In Shrimp Ponds With Photovoltaic (PV)-Based Energy Source

Introduction: Shrimp has great potential to be used as a business field in Indonesia. Especially in Parigi Regency itself, there are now many shrimp ponds that can be found because of the benefits obtained, so people are interested in making shrimp farming a livelihood. One of the main problems of shrimp ponds is pond water quality. There are several factors that affect pond water quality, namely water temperature, water pH, and water salinity, good pond water quality management can maintain quality standards and can increase shrimp yield and productivity Method: To facilitate the shrimp farmers, innovations need to be made in order to help the shrimp farmers manage their shrimp ponds, therefore using a remote water quality monitoring was system in shrimp ponds with photovoltaic (PV) based energy sources is expected to be an innovation in managing shrimp ponds, especially in monitoring water quality in shrimp ponds. The monitoring system designed using the NRF24L01 module as a remote communication module, at the research location the distance from the shrimp pond to the house is approximately 100 meters, so the tools that have been designed can facilitate shrimp farmers to monitor the shrimp pond Results and Disscussion: The results of testing the DS18B20 temperature sensor compared with a digital thermometer measuring instrument get an average error of 0.014%. The test results of the pH sensor compared to the pH meter get an average error of 0.026%. TDS sensor test results compared with the TDS meter get an average error of 0.04%. Conclusion: The temperature, pH, and salinity monitoring system uses transmitter and receiver modules, where the transmitter module reads and sends data to the receiver module wirelessly with NRF24L01. Using DS18B20 temperature, pH, and TDS sensors, as well as energy from photovoltaics, this system helps shrimp farmers monitor pond water quality remotely.

Dual-modal fiber-optic sensor for simultaneous pH and temperature monitoring in tumor microenvironment

The tumor microenvironment (TME) is a complex system. Temperature, pH, oxygen content, and other biomarkers comprehensively reflect the growth state of the tumor, necessitating a multi-parameter detection strategy to garner the precise status of tumor for treatment guidance. Fluorescence imaging technology is a promising tool for realizing this goal due to its advantages of low cost, real-time responses, and high sensitivity. However, several limitations, including the shallow penetration depth of fluorescence signals in biological tissues and the potential crosstalk between multiple fluorescence signals, hinder the practical application of current fluorescence imaging technology. In this paper, a dual-mode optical fiber sensor consisting of a fiber fluorescence pH sensor and a fiber Bragg grating (FBG) temperature sensor is presented. The compact sensor uses different principles for pH and temperature monitoring, thus effectively eliminating potential crosstalk between different signals. In addition, its small size allows it to be inserted into deep tissues for detection. The sensor responds quickly to changes in pH.Moreover, the temperature sensitivity of FBG packaged with PDMS is 34 % higher than the uncoated FBG. In vivo experiments confirmed that the sensor can accurately distinguish normal tissues and tumor tissues. The proposed sensor provides a novel way to realize multi-parameter monitoring of tumor microenvironment and improve the specificity of tumor detection.

Development of a novel ratiometric fluorescent probe for real-time monitoring of acidic pH and its applications in food samples and biosystem

In this research, a high-efficiency ratiometric fluorescent probe TZTF for sensitive detecting the fluctuations of acidic pH was synthesized. The fluorescent color changed from bright blue to orange in the pH values range from 8.0 to 1.0 with the pKa value of 5.41. Meanwhile, the probe demonstrated excellent selectivity, good anti-interference ability, prominent reversibility, outstanding photostability, and low cytotoxicity. The detection mechanism of TZTF towards acidic pH was verified through 1H NMR analysis and DFT calculation. Additionally, probe TZTF was also applied to evaluate the freshness of meat samples, as the pH value of meat samples may decrease if they are not stored properly, and the subsequent acid-catalyzed denaturation of proteins may pose a threat to human health through the food chain. More importantly, fluorescence imaging experiments confirmed that TZTF is appropriate for real-time tracking of pH variations in living cells and living zebrafish.

Influencing mechanism of farming clams on the CO2 flux from aquaculture ponds: Insights from ecosystem carbon metabolism

Aquaculture ponds have garnered increasing attention for their potential roles in the global carbon cycle within the context of global warming. As a significant co-culture species in mariculture ponds, clams exert a notable impact on CO2 flux across the water-air interface. However, the mechanism underlying this influence is as yet unclear. This study measured the CO2 flux as well as the ecosystem carbon metabolism and environmental physiochemical parameters from four marine polyculture ponds, i.e., the pond containing swimming crabs and kuruma shrimp was referred to as CS, and the other three ponds containing three varying densities of razor clams additionally based on CS were noted as CSB1, CSB2, and CSB3 in order of increasing clam density. All the bi-species and tri-species polyculture ponds acted as atmospheric CO2 sinks during the farming season, with the peak in CSB1 and the lowest in CSB3. Net ecosystem production was a dominant regulator of CO2 uptake, and sediment respiration significantly increased CO2 production and then affected the CO2 flux, contributing 16.7–20.0 % to the ecosystem respiration (ER). Water pH could function as a potentially reliable CO2 flux predictor in the polyculture ponds, while Chl a was an internal driving factor. The polyculture of clams at low density may have exerted a “bottom-up” effect, accelerating nutrient cycling and thus stimulating the planktonic community, gross primary production (GPP), and ER, whereas a high stocking density of clams can have a “top-down” effect that would have the opposite ecological effects through increased predation pressure from clams. Although GPP and ER were simultaneously promoted or inhibited by clams at different stocking densities, the effect on GPP was always greater than that on ER, resulting in the CO2 sink function that the polyculture ponds performed through the water-air interface being strengthened at low clam densities and weakened at high clam densities. Given the good predictive ability of water pH on CO2 flux, monitoring and management of water pH could be an effective way to regulate the CO2 sink function of mariculture ponds.

Smart Dressings and Their Applications in Chronic Wound Management.

During chronic wound healing, the inflammatory phase can endure for extended periods, heavily impeding or halting the process. Regular inspections and dressing changes are crucial. Modern dressings like hydrogels, hydrocolloids, and foam provide protection and an optimal healing environment. However, they have limitations in offering real-time wound bed status and healing rate. Evaluation relies heavily on direct observation, and passive dressings fail to identify subtle healing differences, preventing adaptive adjustments in biological factors and drug concentrations. In recent years, the clinical field recognizes the value of integrating intelligent diagnostic tools into wound dressings. By monitoring biomarkers linked to chronic wounds' inflammatory state, real-time data can be captured, reducing medical interventions and enabling more effective treatment plans. This fosters innovation in chronic wound care. Researchers have developed smart dressings with sensing, active drug delivery, and self-adjustment capabilities. These dressings detect inflammatory markers like temperature, pH, and oxygen content, enhancing drug bioavailability on the wound surface. As wound healing technology evolves, these smart dressings hold immense potential in chronic wound care and treatment. This comprehensive review updates our understanding on the role and mechanism of action of the smart dressings in chronic refractory wounds by summarizing and discussing the latest research progresses, including the intelligent monitoring of wound oxygen content, temperature, humidity, pH, infection, and enzyme kinetics; intelligent drug delivery triggered by temperature, pH, near-infrared, and electricity; as well as the intelligent self-adjustment of pressure and shape. The review also delves into the constraints and future perspectives of smart dressings in clinical settings, thereby advancing the development of smart wound dressings for chronic wound healing and their practical application in clinical practice.

Real-Time pH Sensor in Bacterial Microenvironments Using Liquid Crystal Core-Shell Microspheres.

It is well-known that the bacterial microenvironment imposes restrictions on the growth and behavior of bacteria. The localized monitoring of microenvironmental factors is appreciated when consulting bacterial adaptation and behavior in the presence of chemical or mechanical stimuli. Herein, we developed a novel liquid crystal (LC) biosensor in a microsphere configuration for real-time 3D monitoring of the bacteria microenvironment, which was implemented by a microfluidic chip. As a proof of concept, a LC gel (LC-Gel) microsphere biosensor was prepared and employed in the localized pH changes of bacteria by observing the configuration change of LC under polarized optical microscopy. Briefly, the microsphere biosensor was constructed in core-shell configuration, wherein the core contained LCE7 (a nematic LC) doped with 4-pentylbiphenyl-4'-carboxylic acid (PBA), and the shell encapsulated the bacteria. The protonation of carboxyl functional groups of the PBA induced a change in charge density on the surface of LCE7 and the orientation of E7 molecules, resulting in the transitions of the LC nucleus from axial to bipolar. The developed LC-Gel microspheres pH sensor exhibited its dominant performance on localized pH real-time sensing with a resolution of 0.1. An intriguing observation from the prepared pH biosensor was that the diverse bacteria impelled distinct acidifying or alkalizing effects. Overall, the facile LC-Gel microsphere biosensor not only provides a versatile tool for label-free, localized pH monitoring but also opens avenues for investigating the effects of chemical and mechanical stimuli on cellular metabolism within bacterial microenvironments.

Real-Time Monitoring of Photoinduced pH Jumps by In Situ Rapid-Scan EPR Spectroscopy.

This work represents the first demonstration of monitoring kinetics upon a light-induced pH jump by in situ rapid-scan (RS) electron paramagnetic resonance (EPR) spectroscopy on the millisecond time scale. Here, we focus on the protonation state of an imidazolidine type radical as a pH sensor under visible light irradiation of a merocyanine photoacid in bulk solution. The results highlight the utility of photoacids in combination with pH-sensitive spin probes as an effective tool for the real-time investigation of biochemical mechanisms regulated by changes in the pH value.

Portable Photoacoustic Analytical System Combined with Wearable Hydrogel Patch for pH Monitoring in Chronic Wounds.

Timely diagnosis, monitoring, and management of chronic wounds play crucial roles in improving patients' quality of life, but clinical evaluation of chronic wounds is still ambiguous and relies heavily on the experience of clinician, resulting in increased social and financial burden and delay of optimal treatment. During the different stages of the healing process, specific and dynamic changes of pH values in the wound exudate can be used as biomarkers to reflect the wound status. Herein, a pH-responsive agent with well-behaved photoacoustic (PA) properties, nitrazine yellow (NY), was incorporated in poly(vinyl alcohol)/sucrose (PVA/Suc) hydrogel to construct a wearable pH-sensing patch (PVA/Suc/NY hydrogel) for monitoring of pH values during chronic wound healing. According to Rosencwaig-Gersho theory and the combination of 3D printing technology, the PA chamber volume and chopping frequency were systematically optimized to improve the sensitivity of the PA analytical system. The prepared PVA/Suc/NY hydrogel patch had excellent mechanical properties and flexibility and could maintain conformal contact with skin. Moreover, combined with the miniaturized PA analytical device, it had the potential to detect pH values (5.0-9.0) free from the color interference of blood and therapeutic drugs, which provides a valuable strategy for wound pH value monitoring by PA quantitation. This strategy of combining the wearable hydrogel patch with portable PA analysis offers broad new prospects for the treatment and management of chronic wounds due to its features of simple operation, time savings, and anti-interference.

Gastroesophageal reflux disease after laparoscopic sleeve gastrectomy

Background. GastroEsophageal Reflux Disease (GERD) is a common problem among obese and overweight people, including as a complication of bariatric surgery, Laparoscopic Sleeve Gastrectomy (LSG). Aim. To conduct a retrospective analysis of the frequency of GERD in patients with morbid obesity after laparoscopic sleeve gastrectomy. Materials and Methods. In this retrospective study, data from 152 patients who underwent LSG were analyzed. All patients were diagnosed with morbid obesity and were deemed suitable for surgery. The minimum follow-up period was twelve months. All patients were assessed preoperatively for the severity of GERD using 24-hour pH monitoring, and upper gastrointestinal tract examination via FibroGastroDuodenoScopy (FGDS) to identify signs of reflux disease, esophagitis and Barrett's esophagus and GERD-HRQL (Health-Related Quality of Life) questionnaire. Results. During the study, out of 152 patients without GERD (DeMeester Index (DMI) was 6.87±3.38), 23 (15.1%) of them within 12 months after LSG developed de novo GERD (DMI 9.12±8.87, p=0.04). In four patients with de novo GERD, esophagitis grade A was detected. The pathomechanism of GERD following LSG was multifactorial, caused by a combination of anatomical, physiological, and physical factors. Contributing factors included the shape of the sleeve, damage to the lower esophageal sphincter, and esophageal motility disorders. Conclusions. LSG is effective in promoting weight loss, but poses a significant risk of developing GERD. Our study found a 15.1% incidence of GERD after LRH, which is lower than other studies, probably due to the routine use of 24-hour pH monitoring to identify patients with asymptomatic GERD. Anatomical changes due to LSG, in particular resection of the gastric fundus and dissection in the area of the angle of His, increase the temporary relaxation of the lower esophageal sphincter, contributing to the development of GERD. Keywords: bariatric surgery, morbid obesity, GERD.

Gastroesophageal reflux disease after laparoscopic sleeve gastrectomy

Background. GastroEsophageal Reflux Disease (GERD) is a common problem among obese and overweight people, including as a complication of bariatric surgery, Laparoscopic Sleeve Gastrectomy (LSG). Aim. To conduct a retrospective analysis of the frequency of GERD in patients with morbid obesity after laparoscopic sleeve gastrectomy. Materials and Methods. In this retrospective study, data from 152 patients who underwent LSG were analyzed. All patients were diagnosed with morbid obesity and were deemed suitable for surgery. The minimum follow-up period was twelve months. All patients were assessed preoperatively for the severity of GERD using 24-hour pH monitoring, and upper gastrointestinal tract examination via FibroGastroDuodenoScopy (FGDS) to identify signs of reflux disease, esophagitis and Barrett's esophagus and GERD-HRQL (Health-Related Quality of Life) questionnaire. Results. During the study, out of 152 patients without GERD (DeMeester Index (DMI) was 6.87±3.38), 23 (15.1%) of them within 12 months after LSG developed de novo GERD (DMI 9.12±8.87, p=0.04). In four patients with de novo GERD, esophagitis grade A was detected. The pathomechanism of GERD following LSG was multifactorial, caused by a combination of anatomical, physiological, and physical factors. Contributing factors included the shape of the sleeve, damage to the lower esophageal sphincter, and esophageal motility disorders. Conclusions. LSG is effective in promoting weight loss, but poses a significant risk of developing GERD. Our study found a 15.1% incidence of GERD after LRH, which is lower than other studies, probably due to the routine use of 24-hour pH monitoring to identify patients with asymptomatic GERD. Anatomical changes due to LSG, in particular resection of the gastric fundus and dissection in the area of the angle of His, increase the temporary relaxation of the lower esophageal sphincter, contributing to the development of GERD. Keywords: bariatric surgery, morbid obesity, GERD.

Modified One Anastomosis Gastric Bypass Following Sleeve Gastrectomy for Severe Reflux and Delayed Gastric Emptying: A Prospective Trial with Clinical and Physiological Outcome Measures.

Gastro-esophageal reflux (GORD) following sleeve gastrectomy (SG) is a central challenge, and precise indications for revisional surgery or the physiology have not been precisely defined. We aimed to determine whether OAGB performed for reflux post-SG (1) accelerates gastric emptying half-time, (2) reduces the frequency and severity of reflux events, and (3) improves reflux symptoms. We undertook a prospective trial (ACTRN12616001089426). There were 22 participants who underwent measurement before and after revisional surgery with 29 optimal SG (patients with optimal outcome from their primary surgery) as controls. All participants underwent a protocolized nuclear scintigraphy, 24-h pH monitoring, and gastroscopy and completed objective questionnaires. Trial patients were 90.9% female, age 44.4years. Conversion from SG to OAGB was at a median of 45.2 ± 19.6months. Scintigraphy showed an increased rate of gastric emptying post-OAGB 34 (IQR 14) vs 24 (IQR 10.3) min, p-value 0.008, with decreased number of reflux events post-prandially (39 (IQR 13) vs 26 (IQR 7), p-value 0.001). This data correlated with the pH analysis; total acid events substantially reduced post-OAGB 58.5 (IQR 88) vs 12 (IQR 9.4) events, p-value 0.017. Endoscopic findings indicated a reduction in incidence of bile stasis 72.7% vs 40.9% post-OAGB, p-value < 0.00010. Post-OAGB, patients experienced less frequent regurgitation (12 ± 4.1 vs. 5.5 ± 3, p-value 0.012) and reflux (37.1 ± 15.7 vs. 16.8 ± 12.6, p-value 0.003). We found OAGB is an effective treatment for reflux associated with delayed gastric emptying post-SG. The likely mechanisms is by, an increase in the rate of gastric clearance and reduced reflux events and overall esophageal acid exposure. This suggests that some forms of post-SG reflux are driven by slower emptying of the residual stomach and are amenable to treatment with drainage above the incisura.

Integration of pH Control into Chi.Bio Reactors and Demonstration with Small-Scale Enzymatic Poly(ethylene terephthalate) Hydrolysis.

Small-scale bioreactors that are affordable and accessible would be of major benefit to the research community. In previous work, an open-source, automated bioreactor system was designed to operate up to the 30 mL scale with online optical monitoring, stirring, and temperature control, and this system, dubbed Chi.Bio, is now commercially available at a cost that is typically 1-2 orders of magnitude less than commercial bioreactors. In this work, we further expand the capabilities of the Chi.Bio system by enabling continuous pH monitoring and control through hardware and software modifications. For hardware modifications, we sourced low-cost, commercial pH circuits and made straightforward modifications to the Chi.Bio head plate to enable continuous pH monitoring. For software integration, we introduced closed-loop feedback control of the pH measured inside the Chi.Bio reactors and integrated a pH-control module into the existing Chi.Bio user interface. We demonstrated the utility of pH control through the small-scale depolymerization of the synthetic polyester, poly(ethylene terephthalate) (PET), using a benchmark cutinase enzyme, and compared this to 250 mL bioreactor hydrolysis reactions. The results in terms of PET conversion and rate, measured both by base addition and product release profiles, are statistically equivalent, with the Chi.Bio system allowing for a 20-fold reduction of purified enzyme required relative to the 250 mL bioreactor setup. Through inexpensive modifications, the ability to conduct pH control in Chi.Bio reactors widens the potential slate of biochemical reactions and biological cultivations for study in this system, and may also be adapted for use in other bioreactor platforms.