Investigation of Thermo-Hydraulics in a Lid-Driven Square Cavity with a Heated Hemispherical Obstacle at the Bottom.

Lid-driven cavity (LDC) flow is a significant area of study in fluid mechanics due to its common occurrence in engineering challenges. However, using numerical simulations (ANSYS Fluent) to accurately predict fluid flow and mixed convective heat transfer features, incorporating both a moving top wall and a heated hemispherical obstruction at the bottom, has not yet been attempted. This study aims to numerically demonstrate forced convection in a lid-driven square cavity (LDSC) with a moving top wall and a heated hemispherical obstacle at the bottom. The cavity is filled with a Newtonian fluid and subjected to a specific set of velocities (5, 10, 15, and 20 m/s) at the moving wall. The finite volume method is used to solve the governing equations using the Boussinesq approximation and the parallel flow assumption. The impact of various cavity geometries, as well as the influence of the moving top wall on fluid flow and heat transfer within the cavity, are evaluated. The results of this study indicate that the movement of the wall significantly disrupts the flow field inside the cavity, promoting excellent mixing between the flow field below the moving wall and within the cavity. The static pressure exhibits fluctuations, with the highest value observed at the top of the cavity of 1 m width (adjacent to the moving wall) and the lowest at 0.6 m. Furthermore, dynamic pressure experiences a linear increase until reaching its peak at 0.7 m, followed by a steady decrease toward the moving wall. The velocity of the internal surface fluctuates unpredictably along its length while other parameters remain relatively stable.

SARS-CoV-2 and the pandemic of COVID-19.

SARS-CoV-2 is a virus that is the cause of a serious life-threatening disease known as COVID-19. It was first noted to have occurred in Wuhan, China in November 2019 and the WHO reported the first case on December 31, 2019. The outbreak was declared a global pandemic on March 11, 2020 and by May 30, 2020, a total of 5 899 866 positive cases were registered including 364 891 deaths. SARS-CoV-2 primarily targets the lung and enters the body through ACE2 receptors. Typical symptoms of COVID-19 include fever, cough, shortness of breath and fatigue, yet some atypical symptoms like loss of smell and taste have also been described. 20% require hospital admission due to severe disease, a third of whom need intensive support. Treatment is primarily supportive, however, prognosis is dismal in those who need invasive ventilation. Trials are ongoing to discover effective vaccines and drugs to combat the disease. Preventive strategies aim at reducing the transmission of disease by contact tracing, washing of hands, use of face masks and government-led lockdown of unnecessary activities to reduce the risk of transmission.

Impact of 'two-week wait' referral pathway on the diagnosis, treatment and survival in upper and lower gastrointestinal cancers.

BACKGROUND: The 'two-week wait'(2WW) referral pathway was introduced in the United Kingdom to reduce waiting times for treatment of cancer. There has been a debate regarding the efficacy of 2WW pathway since its implementation. METHODS: A singleinstitutional analysis of upper gastrointestinal(UGI) and lower gastrointestinal(LGI) malignancies treated between 1April 2015 and 31March 2017 was undertaken to analyse the impact of 2WWreferral pathway on the diagnosis, treatment and survival. RESULTS: 2WW referral does not achieve an earlier diagnosis compared with non-2WW routes of referral in UGI (χ2(3)=2.6, p=0.458) and LGI (χ2(3)=0.884, p=0.829) malignancies. 2WW referral does not lead to an improvement in curative treatment in UGI (OR1.48, 95%CI0.68to3.21, p=0.321) and LGI (OR1.59, 95%CI0.97to2.62, p=0.067) malignancies. No improvement in survival is seen in UGI (HR0.99, 95%CI0.56to1.75, p=0.963) and LGI (HR1.10, 95%CI0.60to1.99, p=0.764) malignancies by virtue of 2WW referral. Emergency presentation is the most common presenting route in UGI malignancy(40%) and is associated with poor survival (HR0.55, 95%CI0.30to0.97, p=0.045).Non-emergency route of presentation is associated with higher rates of curative treatment in UGI malignancies (OR3.49, 95%CI1.57to7.76, p=0.002). Lower rate of curative treatment (OR 0.27, 95%CI0.16to0.43, p<0.001) and poor survival (HR0.44, 95%CI0.26to0.76, p=0.003) is also observed in emergency presentation of LGI malignancy(29%) which is the secondmost common route of presentation in this group. CONCLUSION: 2WW referral does not achieve early diagnosis nor does it lead to an improvement in the rate of curative treatment in UGI and LGI malignancies. No improvement in short-term survival is seen in UGI malignancies nor in LGI malignancies on multivariate analysis by virtue of 2WW referral.

An experimental investigation and flow-system simulation about the influencing of silica-magnesium oxide nano-mixture on enhancing the rheological properties of Iraqi crude oil.

This study aims to investigate the effects of introducing a 50/50 mixture of silica and magnesium oxide nanoparticles (SNP + MgONP) to the viscosity of Al-Ahdab crude oil (Iraq) at varied concentrations and temperatures. It is observed that the viscosity value drops from 38.49 to 7.8 cP. The highest degree of viscosity reduction is measured to be 56.91% at the maximum temperature of 50 °C and the greatest concentration of 0.4 wt% SM4. The Bingham model can be used to classify the behavior of the crude oil before the Nano-mixture is added. The liquid behavior grew closer to Newtonian behavior once the Nano-mixture was added. Along with a rise in plastic and effective viscosity values, the yield stress value decreases as the concentration of the Nano-mixture increases. The numerical data demonstrate that when the volume proportion of nanoparticles increases, the pressure distribution decreases. Furthermore, as the nanoparticle volume fraction increases, the drag decrease would also increase. SM4 obtains a maximum drag reduction of 53.17%. It is discovered that the sample SM4 has a maximum flow rate increase of 2.408%. Because they reduce the viscosity of crude oil, nanoparticles also reduce the friction factor ratio.

Investigating the Impact of Cell Inclination on Phase Change Material Melting in Square Cells: A Numerical Study.

In order to determine the ideal degree of inclination that should be employed for constructing effective thermal energy storage systems, it is important to examine the impact of inclination angle on the melting behavior of phase change materials (PCMs) such as paraffin wax within a square cell. In consequence, this would guarantee the greatest capacity for energy release and storage. Additionally, analyzing this influence aids engineers in creating systems that enhance heat flow from external sources to the PCM and vice versa. To find out how the cell's inclination angle affects the melting of PCM of paraffin wax (RT42) inside a square cell, a numerical analysis is carried out using the ANSYS/FLUENT 16 software. Specifically, the temperature and velocity distributions, together with the evolution of the melting process, will be shown for various inclination angles, and a thorough comparison will be made to assess the influence of inclination angle on the PCM melting process and its completion. The findings demonstrated that when the cell's inclination angle increased from 0° to 15° and from 0° to 30° and 45°, respectively, the amount of time required to finish the melting process increased by 15%, 42%, and 71%, respectively. Additionally, after 210 min of operation, the PCM's maximum temperature is 351.5 K with a 0° angle of inclination (horizontal) against 332.5 K with an angle of inclination of 45°.

Systematic Review and Meta-analysis of the Effects of Laparoscopic Roux-en-Y Gastric Bypass and Laparoscopic Sleeve Gastrectomy on Dyslipidemia.

The aim of this meta-analysis was to compare the effects of LRYGB and LSG on dyslipidemia. Studies comparing the effects of LRYGB and LSG on dyslipidemia with follow-up of 12 months or more were included. Twenty-four studies comprising seven RCTs and 17 comparative observational studies were included. Meta-analysis of RCTs (n=487) showed that improvement/resolution of dyslipidemia was better after LRYGB (68.5%, n=161/235) compared to LSG (48.4%, n=122/252). Patients undergoing LRYGB were more than twice as likely to experience improvement/resolution in dyslipidemia compared to those undergoing LSG (OR 2.28, 95% CI 1.21-4.29, p=0.010). Both LRGYB and LSG appears effective in improving dyslipidemia at >12 months after surgery; however, this improvement is more than twice higher after LRYGB compared to LSG.

Impact of Gastrojejunostomy Anastomosis Diameter on Weight Loss Following Laparoscopic Gastric Bypass: A Systematic Review.

Laparoscopic Roux-en-Y gastric bypass (RYGB) is crucial for significant weight reduction and treating obesity-related issues. However, the impact of gastrojejunostomy (GJ) anastomosis diameter on weight loss remains unclear. We investigate this influence on post-RYGB weight loss outcomes. A systematic search was conducted. Six studies met the inclusion criteria, showing varied GJ diameters and follow-up durations (1-5 years). Smaller GJ diameters generally correlated with greater short-to-medium-term weight loss, with a threshold beyond which complications like stenosis increased. Studies had moderate-to-low bias risk, emphasizing the need for precise GJ area quantification post-operation. This review highlights a negative association between smaller GJ diameters and post-RYGB weight loss, advocating for standardized measurement techniques. Future research should explore intra-operative and AI-driven methods for optimizing GJ diameter determination.

Patient and operative factors influence delayed discharge following bariatric surgery in an enhanced recovery setting.

BACKGROUND: Enhanced Recovery After Surgery (ERAS) programs have been widely adopted in bariatric surgery. However, not all patients are successfully managed in the ERAS setting and there is currently little way of predicting the patients who will deviate from the program. Early identification of these patients could allow for more tailored protocols to be implemented preoperatively to address the issues, thereby improving patient outcomes. OBJECTIVES: The aim of this study was to elucidate the factors which preclude discharge by comparing patients who were successfully discharged by the end of the first postoperative day (POD 0/1) to those who stayed longer, including revisional surgery in this analysis. SETTING: A tertiary, high-volume Bariatric Centre, United Kingdom. METHODS: A retrospective analysis was performed of all patients undergoing bariatric surgery in a single centre in 1 year. Multivariate analyses compared patient and operative variables between patients who were discharged on POD 0/1 and those who stayed longer. RESULTS: A total of 288 bariatric operations were performed: 78% of operations performed were laparoscopic Roux-en-Y gastric bypass; 22% laparoscopic sleeve gastrectomy. Of these cases, 13% were revisional operations. Four patients returned to theatre on the index admission. 81% of patients were discharged by POD 0/1. A re-presentation within 30 days was seen in 6% of patients. There was no significant difference in length of stay for the type of operation performed (P = .86). Patients who had a revisional procedure were not more likely to stay longer. Length of stay was also independent of age, BMI, and comorbidities. Caucasian patients were more likely to be discharged on POD 0/1 than those of other ethnicities (90% versus 78%; P = .02). Operations performed by trainee surgeons, under consultant supervision, were significantly more likely to be discharged on POD 0/1 (P = .03). However, a logistic regression analysis was unable to predict patients who had a prolonged stay. CONCLUSIONS: Patient length of stay is independent of BMI, operation, and comorbidities and these factors do not need special consideration in ERAS pathways. Patients undergoing revisional procedures can be managed in the same way as those having primary procedures, with a routine POD 0/1 discharge. However, the impact of individual patient factors, and their interaction, is complex and cannot predict overstay.

Laparoscopic Repair of Blunt Traumatic Diaphragmatic Hernia.

Traumatic diaphragmatic hernias (TDHs) can occur after both blunt and penetrating injury. Laparotomy and thoracotomy are commonly done for the management of TDHs. Minimally invasive surgery, especially laparoscopic surgery, is being accepted as an effective and safe alternative to open surgical repair even in trauma cases. Laparoscopy also allows for the detection and management of clinically occult TDHs, thereby preventing the complications of missed or delayed diagnosis. Our case highlights the importance of timely intervention with a minimally invasive approach. A 39-year-old male presented to the emergency room after a road traffic accident. Computed tomography scan confirmed left-sided diaphragmatic rupture with gastric herniation. Laparoscopic repair of the hernia was done. He had an uneventful post-operative period. At the one-year follow-up, he was asymptomatic and was doing well. TDHs have a variable clinical presentation and radiological findings are not always diagnostic. Such cases can progress to potentially life-threatening complications such as strangulation and perforation of the herniated viscera. Timely diagnosis and management are therefore essential. A minimally invasive approach such as laparoscopy should be used for the management of TDHs in the acute setting where the patient is stable, and resources are available. In this case, once the gastric contents were aspirated via a nasogastric tube in the middle of the night, the immediate need for surgery was converted to an urgent nature, and the patient underwent surgery the next morning in a more controlled setting. In addition, timely intervention can prevent future complications that may occur if the condition is left untreated during the initial admission.

COVID-19 Diagnosis in Patients With Acute Abdominal Pain Without Respiratory Symptoms: A UK Emergency General Surgical Unit Experience.

BACKGROUND: Recent evidence has emerged reporting atypical clinical symptoms of the novel coronavirus (COVID-19). There is a sparsity of existing studies examining COVID-19-related abdominal pain and the role of investigative imaging for the virus in these patients. Study aims were to determine COVID-19 incidence in those with acute abdominal pain in the absence of respiratory symptoms and to assess the diagnostic performance of CT thoracic imaging in such patients. METHODS: Retrospective analysis of all consecutive patients admitted to our emergency general surgical unit between 1st March 2020 and 31st May 2020 was performed. In adherence with national guidelines, all patients underwent nasal and oro-pharyngeal COVID-19 RT-PCR swabs as well as thoracic and abdominal computed tomography (CT) on admission. RESULTS: From 112 patients admitted with acute abdominal pain in the absence of respiratory symptoms, 16 (14.3%) tested positive for COVID-19 on RT-PCR swab testing. Overall, 50% (8/16) of these patients had no intra-abdominal pathology on CT. The sensitivity and specificity of CT thoracic imaging for diagnosing COVID-19 was 43.8% and 91.7%, respectively. Patients with positive COVID-19 swabs had higher C-reactive protein levels, lower potassium levels and a higher proportion of those with a low lymphocyte count. DISCUSSION: One in seven patients with abdominal pain without any respiratory symptoms tested positive for COVID-19. Half of these patients represented COVID-19 manifesting primarily as acute abdominal pain. Combined swab testing and CT imaging should be performed in all abdominal pain presentations due to the varying diagnostic performance of thoracic CT in diagnosing COVID-19.

The surgical management of obesity.

Obesity has reached pandemic levels globally. Surgical management of obesity aims to establish metabolic control, weight loss and resolution of multiple health conditions and to improve quality of life. Here, we examine the role of surgery in the management of obesity within the context of a multidisciplinary team involving a variety of healthcare professionals. We highlight the importance of patient selection, perioperative care, the various types of bariatric surgery currently available as well as emerging procedures. In addition to clarifying the different types of procedure, we also examine the potential complications and issues of weight regain and failure to lose weight. Ultimately, bariatric surgery remains comparatively safe and with generally excellent results in terms of control of existing obesity-related conditions; with the ever-increasing number of patients living with obesity, the scope of bariatric surgery is thus likely to increase.

Complex dynamics of induced vortex formation and thermal-fluid coupling in tri-hybrid nanofluid under localized magnetic field: a novel study.

Hybrid nanofluids offer higher stability, synergistic effects, and better heat transfer compared to simple nanofluids. Their higher thermal conductivity, lower viscosity, and interaction with magnetic fields make them ideal for various applications, including materials science, transportation, medical technology, energy, and fundamental physics. The governing partial differential equations are numerically solved by employing a finite volume approach, and the effects of various parameters on the nanofluid flow and thermal characteristics are systematically examined from the simulations based on a self-developed MATLAB code. The parameters included magnetic field strength, the Reynolds number, the nanoparticle volume fraction, and the number and position of the strips in which the magnetic field is localized. It has been noted that the magnetized field induces the spinning of the tri-hybrid nanoparticles, which generates the intricate structure of vortices in the flow. The local skin friction (CfRe) and the Nusselt number (Nu) increase significantly when the magnetic field is intensified. Moreover, adding more nanoparticles in the flow enhances both Nu and CfRe, but with different effects for different nanoparticles. Silver (Ag) shows the highest increase in both Nu (52%) and CfRe (110%), indicating strong thermal-fluid coupling. Alumina (Al2O3) and Titanium Dioxide (TiO2) show lower increases in both Nu (43% and 34%) and CfRe (14% and 10%), indicating weaker coupling in the flow. Finally, compared with the localized one, the uniform magnetic field has a minor effect on the flow and temperature distributions.

Acute mesenteric ischemia and duodenal ulcer perforation: a unique double pathology.

BACKGROUND: Acute mesenteric ischaemia and duodenal perforation are surgical emergencies with serious consequences. Patients presenting with acute mesenteric ischaemia alone face a high mortality rate as high as 60% whereas those presenting with peptic ulcer perforation the mortality rates range from 6-14%. There are very few reported cases of patients presenting with this dual pathology. CASE PRESENTATION: We report a unique case of a 53 year old Italian lady who presented with acute mesenteric ischaemia and duodenal perforation. This is the first report of massive bowel ischaemia and duodenal perforation with no apparent underlying common pathophysiology leading to this presentation. CONCLUSION: Early management in the intensive care unit and appropriate surgical intervention maximised the patient's chances of survival despite the poor prognosis associated with her dual pathology. The rare pathology of the patient described can be explained by two possible hypotheses: peptic ulcer disease causing duodenal ulceration, which precipitated ischaemic infarction of the small bowel. The second hypothesis is the patient developed a stress related ulcer following ischaemic bowel infarction secondary to arterial thrombosis.

Review of Heat Transfer Analysis in Different Cavity Geometries with and without Nanofluids.

Many strategies have been attempted for accomplishing the needed changes in the heat-transfer rate in closed cavities in recent years. Some strategies used include the addition of flexible or hard partitions to the cavities (to split them into various pieces), thickening the borders, providing fins to the cavities, or altering the forms or cavity angles. Each of these methods may be used to increase or decrease heat transmission. Many computational and experimental investigations of heat transport in various cavity shapes have been conducted. The majority of studies focused on improving the thermal efficiency of heat transmission in various cavity containers. This paper introduced a review of experimental, numerical, and analytical studies related to heat transfer analyses in different geometries, such as circular, cylindrical, hexagonal, and rectangular cavities. Results of the evaluated studies indicate that the fin design increased heat transmission and sped up the melting time of the PCM; the optimal wind incidence angle for the maximum loss of combined convective heat depends on the tilt angle of the cavity and wind speed. The Nusselt number graphs behave differently when decreasing the Richardson number. Comparatively, the natural heat transfer process dominates at Ri = 10, but lid motion is absent at Ri = 1. For a given Ri and Pr, the cavity without a block performed better than the cavity with a square or circular block. The heat transfer coefficient at the heating sources has been established as a performance indicator. Hot source fins improve heat transmission and reduce gallium melting time.

The Role of Relaparoscopy in the Management of Early Bariatric Surgery Complications and 30-Day Outcome: a Tertiary Centre Experience.

The laparoscopic approach for dealing with bariatric complications has become the gold standard of modern practice. The aim of this study is to assess the role of relaparoscopy as a diagnostic and therapeutic approach towards managing complications and improving 30-day outcome. MATERIALS AND METHODS: A retrospective review of a prospectively maintained database was conducted in a tertiary bariatric unit. Data were collected on all bariatric surgical procedures performed between March 2013 and March 2019. Any patient who was returned to theatre for a suspected serious complication was identified and their outcome studied. RESULTS: Over the 5-year study period, the total number of operations performed was 1660 (981 laparoscopic gastric bypass (LRYGB), 612 laparoscopic sleeve gastrectomy (LSG) and 67 revisional bariatric operations). Early postoperative complications (in hospital or within 30 days of surgery) that lead to reoperation were recorded in 33 patients (1.9%). These complications occurred after LRYGB in 26 patients (2.65%) and LSG in 7 patients (1.14%), respectively. Anastomotic leaks occurred in 1.1% of LRYGB, whilst 0.6% of patients have jejuno-jejunostomy obstruction. Obstruction at the gastro-jejunostomy anastomosis occurred in one patient. Following LSG, one mortality was recorded following bleeding from the staple line (0.06%) and five patients (0.3%) had leaks from the staple line. Thirty-one reoperations were performed laparoscopically, and two were converted to the open approach, whilst 2 operations were planned as open from the outset. CONCLUSION: Relaparoscopy is an effective and safe approach to the management of clinically or radiologically suspected early complications after bariatric surgery. Graphical abstract.

Probing the link between oestrogen receptors and oesophageal cancer.

BACKGROUND: Human oesophageal carcinoma is considered to be one of the most aggressive malignancies and has a very poor prognosis. The incidence of oesophageal cancer shows a gender bias and is higher in males compared with females, the ratio between males and females varying from 3:1 to 7:1. This sex ratio is not entirely attributable to differences in the prevalence of known risk factors between the sexes. The potential role of oestrogen receptors (ER) in oesophageal cancer has been debated for several years but the significance of the receptors in this cancer remains unknown. Most of the work has been based on immunohistochemistry and has not been validated with other available techniques. The inconsistencies in the published literature on the link between ER expression and oesophageal cancer warrant a thorough evaluation of the potential role of ERs in this malignancy. Even the expression of the two ER isoforms, ERalpha and ERbeta, and its implications for outcome of treatments in histological subtypes of oesophageal tumours is ill defined. The aim of this article is to provide updated information from the available literature on the current status of ER expression in oesophageal cancer and to discuss its potential therapeutic role. METHODS AND RESULTS: We performed a comprehensive literature search and analysed the results regarding ER expression in oesophageal tumours with special emphasis on expression of different oestrogen receptors and the role of sex hormones in oesophageal cancer. This article also focuses on the significance of the two main ER subtypes and mechanisms underlying the presumed male predominance of this disease. CONCLUSION: We postulate that differential oestrogen receptor status may be considered a biomarker of poor clinical outcome based on tissue dedifferentiation or advanced stage of the disease. Further, if we can establish the importance of oestrogen and its receptors in the context of oesophageal cancer, then this may lead to a new future direction in the management of this malignancy.

A pre-operative elevated neutrophil: lymphocyte ratio does not predict survival from oesophageal cancer resection.

BACKGROUND: Elevated pre-operative neutrophil: lymphocyte ratio (NLR) has been identified as a predictor of survival in patients with hepatocellular and colorectal cancer. The aim of this study was to examine the prognostic value of an elevated preoperative NLR following resection for oesophageal cancer. METHODS: Patients who underwent resection for oesophageal carcinoma from June 1997 to September 2007 were identified from a local cancer database. Data on demographics, conventional prognostic markers, laboratory analyses including blood count results, and histopathology were collected and analysed. RESULTS: A total of 294 patients were identified with a median age at diagnosis of 65.2 (IQR 59-72) years. The median pre-operative time of blood sample collection was three days (IQR 1-8). The median neutrophil count was 64.2 x 10-9/litre, median lymphocyte count 23.9 x 10-9/litre, whilst the NLR was 2.69 (IQR 1.95-4.02). NLR did not prove to be a significant predictor of number of involved lymph nodes (Cox regression, p = 0.754), disease recurrence (p = 0.288) or death (Cox regression, p = 0.374). Furthermore, survival time was not significantly different between patients with high (>or= 3.5) or low (< 3.5) NLR (p = 0.49). CONCLUSION: Preoperative NLR does not appear to offer useful predictive ability for outcome, disease-free and overall survival following oesophageal cancer resection.

Long-Term Outcomes and Quality of Life at More than 10 Years After Laparoscopic Roux-en-Y Gastric Bypass Using Bariatric Analysis and Reporting Outcome System (BAROS).

INTRODUCTION: Literature on long-term (> 10 years) outcomes in terms of weight loss, resolution of co-morbidities, and quality of life (QoL) after bariatric surgery is limited. The aim of this study was to investigate the excess weight loss (EWL), resolution of comorbidities, and QoL more than 10 years after laparoscopic Roux-en-Y gastric bypass (LRYGB) using the Bariatric Analysis and Reporting Outcome System (BAROS). METHODS: Data on patient demographics, weight, body mass index (BMI), comorbidities, type of surgery, complications, and QoL were collected from a prospectively maintained database. RESULTS: A total of 92 patients out of 104 who underwent LRYGB during the study period and completed a median follow-up of 130 months were successfully contacted. The median age was 48 years (IQR 42-54 years) and 85.9% had a BMI of more than 40. The median excess weight loss (EWL) was 46.5% (IQR 27.9-64.3%). Type 2 diabetes mellitus reduced from 56.5 to 23.9% (p < 0.001), hypertension from 51.1 to 39.1% (p = 0.016), and obstructive sleep apnoea from 33.7 to 12.0% (p < 0.001). Participants reported feeling better (median 0.2, IQR 0.2-0.4), engaging in more physical activity (0.1, IQR 0.1-0.3), having more satisfactory social contacts (0.4, IQR 0.2-0.5), a better ability to work (0.3, IQR - 0.1-0.5), and a healthier approach to food (0.2, IQR - 0.3-0.3) at the end of follow-up. CONCLUSION: LRYGB leads to positive outcomes in terms of weight loss, reduction in comorbidities, and improvement in QoL at a follow-up of more than 10 years.

A Systematic Review and Meta-Analysis of the Effect of Roux-en-Y Gastric Bypass on Barrett's Esophagus.

BACKGROUND: Obesity is associated with a twofold risk of gastroesophageal reflux disease (GERD) and thrice the risk of Barrett's esophagus (BE). Roux-en-Y gastric bypass (RYGB) leads to weight loss and improvement of GERD in population with obesity, but its effect on BE is less clear. METHODS: Bibliographic databases were searched systematically for relevant articles till January 31, 2019. Studies evaluating the effect of RYGB on BE with preoperative and postoperative endoscopy and biopsy were included. Study quality was assessed using the Methodological Index for Non-Randomized Studies (MINORS) tool. Meta-analysis was conducted using Mantel-Haenszel, random effects model and presented as risk difference (RD) or odds ratio (OR) with 95% confidence intervals. RESULTS: Eight studies with 10,779 patients undergoing RYGB reported on 117 patients with BE with follow-up of > 1 year. Significant regression of BE after RYGB was observed (RD - 0.56.95% c.i. - 0.69 to - 0.43; P < 0.001). Subgroup analysis showed regression of both short-segment BE [ssBE] (RD - 0.51.95% c.i. - 0.68 to - 0.33; P < 0.001) and long-segment BE [lsBE] (RD - 0.46.95% c.i. - 0.71 to - 0.21; P < 0.001). RYGB also caused improvement in GERD in patients of BE (RD - 0.93, 95% c.i. - 1.04 to - 0.81; P < 0.001). RYGB was strongly associated with regression of BE compared with progression (OR 31.2.95% c.i. 11.37 to 85.63; P < 0.001). CONCLUSIONS: RYGB leads to significant improvement of BE at > 1 year after surgery in terms of regression and resolution of the associated GERD. Both ssBE and lsBE improve after RYGB significantly.

Meta-analysis of the effect of bariatric surgery on physical activity.

BACKGROUND: Obesity leads to impairment of physical activity as measured by an inability to perform activities of daily living. Literature on the effect of bariatric surgery on physical activity is conflicting. OBJECTIVE: The aim of this study was to perform a meta-analysis of the effect of bariatric surgery on physical activity from studies employing objective measurement and self-reporting of physical activity before and after bariatric surgery. METHODS: Bibliographic databases were searched systematically for relevant literature until December 31, 2018. Studies employing objective and self-reported measurement of physical activity were included. Study quality was assessed using Risk of Bias in Nonrandomized Studies - of Interventions tool. Meta-analysis was performed using random effects model and presented as standardized mean difference (SMD) with 95% confidence intervals (CI). RESULTS: Twenty studies identified 5886 patients suitable for the analysis. Physical activity showed significant improvement at 0-6 months (SMD: .50; 95% CI: .25-.76; P = .0001), >6-12 months (SMD: .58; 95% CI: .26-.91; P = .0004), and >12-36 months (SMD: .82; 95% CI: .27-1.36; P = .004) after bariatric surgery. Self-reported assessment after bariatric surgery showed significant improvement at 0-6 months (SMD: .65; 95% CI: .29-1.01; P = .0004), >6 to 12 months (SMD: .53; 95% CI: .18-.88; P = .003), and >12-36 months (SMD: .51; 95% CI: .46-.55; P < .00001). Objective assessment after bariatric surgery did not show improvement at 0-6 months (SMD: .31; 95%CI:-.05-.66; P = .09), but showed significant improvement at >6-12 months (SMD: .85; 95% CI:-.07-1.62; P = .03), and >12-36 months (SMD: 1.99; 95% CI: 1.13-2.86; P < .00001) after bariatric surgery. CONCLUSIONS: Bariatric surgery improves physical activity significantly in a population with obesity up to 3 years after surgery. Objective measurement of physical activity does not show significant improvement within 6 months of bariatric surgery but begins to improve at >6 months. Self-reported measurement of physical activity begins to show improvement within 6 months of a bariatric procedure.