Obesity related pathophysiological aspects favouring Gastroesophageal Reflux Disease

Gastroesophageal reflux disease (GERD) is a complex entity and one of the most frequents in general population. Association of GERD with obesity is clearly defined from an epidemiological point of view, where up to 40% of patients with overweight and obesity present reflux. Most of the risk factors associated to GERD are shared and especially frequent in patients with obesity. The pathophysiology that explain this correlation is complex and multifactorial, and includes both aspects related to physiology of motility, and anatomic changes. The malfunction of the lower esophageal sphincter, the greater transdiaphragmatic pressure gradient, pathological accumulation of fat and the high rate of hiatal hernia that comes with overweight will be the main factors that explain this correlation. Other factor like pathological eating habits or obesity related diseases have also an important role. In summary, it is the sum of the factors more than just one of them what would explain the pathophysiology of GERD in obese population.

Analysis of the Management of Cholelithiasis in Bariatric Surgery Patients: a Single-Center Experience

PURPOSE

Cholelithiasis is an issue in bariatric surgery patients. The incidence of cholelithiasis is increased in morbidly obese patients. After bariatric surgery, the management maybe sometimes challenging. There is no consensus about how to deal with cholelithiasis prior to bariatric surgery.

MATERIALS AND METHODS

A retrospective review from our prospectively collected bariatric surgery database. Primary bariatric procedures from 2009 to 2020 were included. Prevalence of cholelithiasis and its management prior to bariatric surgery and the incidence and management of postoperative biliary events were analyzed.

RESULTS

Over 1445 patients analyzed, preoperatively cholelithiasis was found in 153 (10.58%), and 68 out of them (44.44%) were symptomatic. Seventy-six patients had a concomitant cholecystectomy. In those cases, the bariatric procedure did not show increased operative time, length of stay, morbidity, or mortality compared to the rest of primary bariatric procedures. Twelve patients (15.58%) with previous cholelithiasis and no concomitant cholecystectomy presented any kind of biliary event and required cholecystectomy. De novo cholelithiasis rate requiring cholecystectomy was 3.86%. Postoperative biliary events both in de novo and persistent cholelithiasis population did not show any difference between the type of surgery, weight loss, and other characteristics.

CONCLUSIONS

Cholelithiasis was present in 10.58% of our primary bariatric surgery population. Concomitant cholecystectomy was safe in our series. Non-surgical management of asymptomatic cholelithiasis did not lead to a higher risk of postoperative biliary events. The global postoperative cholecystectomy rate was equivalent to the general population.

Water-soluble polymers in agriculture: xanthan gum as eco-friendly alternative to synthetics

Water-soluble polymers (WSPs) are a versatile group of chemicals used across industries for different purposes such as thickening, stabilizing, adhesion and gelation. Synthetic polymers have tailored characteristics and are chemically homogeneous, whereas plant-derived biopolymers vary more widely in their specifications and are chemically heterogeneous. Between both sources, microbial polysaccharides are an advantageous compromise. They combine naturalness with defined material properties, precisely controlled by optimizing strain selection, fermentation operational parameters and downstream processes. The relevance of such bio-based and biodegradable materials is rising due to increasing environmental awareness of consumers and a tightening regulatory framework, causing both solid and water-soluble synthetic polymers, also termed 'microplastics', to have come under scrutiny. Xanthan gum is the most important microbial polysaccharide in terms of production volume and diversity of applications, and available as different grades with specific properties. In this review, we will focus on the applicability of xanthan gum in agriculture (drift control, encapsulation and soil improvement), considering its potential to replace traditionally used synthetic WSPs. As a spray adjuvant, xanthan gum prevents the formation of driftable fine droplets and shows particular resistance to mechanical shear. Xanthan gum as a component in encapsulated formulations modifies release properties or provides additional protection to encapsulated agents. In geotechnical engineering, soil amended with xanthan gum has proven to increase water retention, reduce water evaporation, percolation and soil erosion - topics of high relevance in the agriculture of the 21st century. Finally, hands-on formulation tips are provided to facilitate exploiting the full potential of xanthan gum in diverse agricultural applications and thus providing sustainable solutions.

Outcomes of Conversion from Sleeve Gastrectomy to Roux-en-Y Gastric Bypass Due to GERD-a Retrospective Analysis of 35 Patients

BACKGROUND

Sleeve gastrectomy (SG) has become one of the most performed bariatric procedures worldwide. Its main weaknesses are weight regain and gastroesophageal reflux disease (GERD). Conversion to Roux-en-Y gastric bypass (RYGB) is considered the gold standard to manage GERD and related symptoms.

METHODS

Retrospective evaluation from a prospective bariatric surgery database of all our institution's patients converted from SG to RYGB due to GERD between January 2010 and December 2018. Clinical characteristics and workups before SG and before and after RYGB were analyzed.

RESULTS

During the study period, 35 patients needed a conversion to RYGB, due to GERD or GERD-related symptoms. Mean age was 48.6 years, 85.7% were women, and mean BMI was 31.4 kg/m². The interval between SG and RYGB was in a range 7 to 70 months (mean 33 months). All conversions were completed laparoscopically, associating a hiatoplasty in 45.7% of cases. A complete remission of symptoms was observed in 74% of patients, some improvement in 20%, and no relief in 6%. There were 3 cases of hiatal hernia persistence and 2 of recidivism. Only 1 patient presented pathological pHmetry, while moderate esophagitis was demonstrated in 2 patients.

CONCLUSIONS

Conversion to RYGB was effective in almost all patients. Pathological acid exposure and hiatal hernias seem to be the main findings prior to conversion, justifying an exhaustive examination and aggressive approach to the hiatus. Due to the insufficient correlation between symptoms and findings on morphological and functional tests, actively searching for signs of GERD is advisable.

Seeking an Initial-Weight-Independent Metric in a Mediterranean Cohort of Gastric Bypass Patients: the %AWL Revisited

BACKGROUND

Most relative weight-loss metrics follow the formula "Weight loss(%) = 100 · (Initial BMI - Final BMI) / (Initial BMI-a)," where a is the reference point that defines the metric. The percentage of total weight loss (%TWL, a = 0) and percentage of excess weight loss (%EWL, a = 25) are influenced by a patient's initial weight. Recently, the percentage of alterable weight loss metric (%AWL, a = 13) has been reported to produce initial-weight-independent outcomes.

OBJECTIVES

This study aimed to replicate the methodology used for %AWL determination in a Mediterranean cohort of bariatric patients.

SETTINGS

Multicenter study in 10 large hospitals in Spain.

METHODS

Two large prospective databases were retrospectively searched for all primary laparoscopic gastric bypass patients with 2 years of follow-up. Outcomes at nadir were expressed and analyzed with 26 different metrics (a from 0 to 25), looking for the metric whose outcomes produced (1) the lowest coefficient of variation, (2) no differences between initially lighter and heavier patients, and (3) no correlation with patients' initial BMI.

RESULTS

A cohort of 1793 patients was stratified into 4 gender-age groups: younger women (YW, n = 733), older women (OW, n = 674), younger men (YM, n = 197), and older men (OM, n = 189). The calculations suggested an optimal reference point of 18 kg/m², defining a new metric (percentage of Mediterranean alterable weight loss, %MAWL). When %TWL, %EWL, %AWL, and %MAWL were tested on the whole sample, only %MAWL produced initial-weight-independent results.

CONCLUSIONS

In our Mediterranean cohort of patients, a reference point of 18 (and not 13) yielded initial-weight-independent outcomes.

Maintenance and assessment of cell viability in formulation of non-sporulating bacterial inoculants

The application of beneficial, plant-associated microorganisms is a sustainable approach to improving crop performance in agriculture. However, microbial inoculants are often susceptible to prolonged periods of storage and deleterious environmental factors, which negatively impact their viability and ultimately limit efficacy in the field. This particularly concerns non-sporulating bacteria. To overcome this challenge, the availability of protective formulations is crucial. Numerous parameters influence the viability of microbial cells, with drying procedures generally being among the most critical ones. Thus, technological advances to attenuate the desiccation stress imposed on living cells are key to successful formulation development. In this review, we discuss the core aspects important to consider when aiming at high cell viability of non-sporulating bacteria to be applied as microbial inoculants in agriculture. We elaborate the suitability of commonly applied drying methods (freeze-drying, vacuum-drying, spray-drying, fluidized bed-drying, air-drying) and potential measures to prevent cell damage from desiccation (externally applied protectants, stress pre-conditioning, triggering of exopolysaccharide secretion, 'helper' strains). Furthermore, we point out methods for assessing bacterial viability, such as colony counting, spectrophotometry, microcalorimetry, flow cytometry and viability qPCR. Choosing appropriate technologies for maintenance of cell viability and evaluation thereof will render formulation development more efficient. This in turn will aid in utilizing the vast potential of promising, plant beneficial bacteria as sustainable alternatives to standard agrochemicals.