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Abdominal wall hernia is a common condition seen in the clinical practice of surgery. However, malignant tumors in the hernia sac are rare and there are limited studies on this subject. We report a case of a 77-year-old female who presented with generalized abdominal pain and vomiting. She was treated for an incarcerated incisional hernia and underwent an exploratory laparotomy, which showed a multiseptated incisional hernia sac. Histopathological examination revealed a metastatic endometrial serous carcinoma (ESC). ESC is an aggressive variant associated with poor prognosis, characterized by metastasis and extrauterine spread. Its treatment mainly involves a multidisciplinary approach, including surgical treatment and chemoradiotherapy. This report highlights the importance of considering malignant tumors in the differential diagnosis of hernia sac contents. Raising awareness among healthcare professionals and the general public can aid in the prompt diagnosis, appropriate treatment, and improved outcomes for individuals with such rare presentations., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Ong et al.)

Obesity stands as a prominent health challenge in our society, with metabolic bariatric surgery (MBS) emerging as a solution due to its efficacy in addressing obesity-related type 2 diabetes mellitus (T2DM). Roux-en-Y gastric bypass (RYGB) and one-anastomosis gastric bypass (OAGB) remain the most common MBS after sleeve gastrectomy. Complications from RYGB are uncommon but include anastomotic stricture, marginal ulcers, small bowel obstruction, and nutritional complications. We present a 52-year-old lady with an initial body mass index (BMI) of 27.6 kg/m 2 and poorly controlled T2DM who presented with generalized body weakness and uncontrolled weight loss after an RYGB performed four months earlier. She was cachexic with a BMI of 17 kg/m 2 ,with generalized anasarca with a multitude of electrolyte disturbances. After nutritional optimization, she underwent a reversal surgery back to normal anatomy. Reversal of RYGB to normal anatomy is a complex surgical procedure and is often the last resort undertaken in patients experiencing severe complications from the initial surgery. Indications include malnutrition, severe dumping syndrome, excessive weight loss, and recalcitrant marginal ulcers. Our case outlines the importance of proper patient selection for MBS and highlights the preoperative management of RYGB reversal to normal anatomy. We also describe the surgical procedure using a stepwise approach. In conclusion, the reversal of RYGB to normal anatomy should only be undertaken after a careful period of prehabilitation to reduce perioperative complications. The inclusion of dietitians, endocrinologists, and physiotherapists is crucial to ensure the best possible outcome., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Sadu Singh et al.)

Introduction: The swallowable intragastric balloon (IGB) has recently emerged as a popular alternative for weight loss in Malaysia. It can reduce total body weight loss (TBWL) by 6-15%. We aim to observe positive weight loss up to a year after the swallowable IGB is implanted., Methods: A total of 486 consecutive patients with overweight or obesity who underwent swallowable IGB insertion were included in this prospective data collection., Results: Out of 486 patients, 404 patients (83%) had complete data at the end of 4 and 12 months. Patients included in the study had a starting mean body mass index of 35.3 ± 7.2 kg/m 2 which decreased to 31.5 ± 5.7 kg/m 2 (p < 0.0001) at the end of 4 months and further reduced to 30.3 ± 5.4 kg/m 2 (p < 0.0001) at the end of 12 months. At 4 months, the overall average weight loss was 9.8 kg, meanwhile, at 12 months, the average weight loss increased to 12.9 kg. At 4 months, the average TBWL was 10.5%, while at the end of 1 year, the combined %TBWL increased to 13.7%., Conclusion: Most weight loss is typically observed within the first 4 months following the procedure. However, it is important to note that patients can continue to experience ongoing weight loss for up to 1 year. The swallowable IGB is a safe and effective option for patients seeking weight loss solutions. It offers numerous advantages, especially its non-invasive procedureless nature, which makes it more appealing to individuals considering this treatment., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Oesophagogastric junction carcinoma is now being increasingly regarded as a distinct site of neoplasia, separate from its adjacent sites. Recent advances in multimodal treatment approaches, including endoscopic procedures, oesophagectomy with three-field lymph node dissection, and definitive chemoradiotherapy, have significantly improved overall patient survival rates. Despite these advancements, the recurrence rate remains around 50% within one to three years following initial surgery. A major challenge in management arises when the resected surgical margins are involved with cancer. We present a 55-year-old man who experienced progressive dysphagia and, upon further assessment, was noted to have a Siewert III oesophagogastric junction adenocarcinoma. He underwent neoadjuvant chemotherapy before undergoing total gastrectomy with D2 lymphadenectomy with a Roux-en-Y reconstruction. Histopathological examination of the resected specimen revealed a positive proximal margin involvement. After optimization, he then underwent a salvage three-field McKeown oesophagectomy with colonic conduit reconstruction and adjuvant chemotherapy. Salvage surgery can be considered for patients with locoregional recurrence after definitive chemoradiotherapy or surgery. Other options include salvage chemoradiotherapy. Our case outlines the importance of proper patient selection for salvage surgery and highlights the choices of conduit in patients undergoing total esophagectomy post gastrectomy.  In conclusion, managing proximal margin involvement of cardioesophageal junction adenocarcinoma remains a complex and multifaceted challenge, necessitating a tailored, multidisciplinary approach. The decision-making process must consider the patient's functional status, previous treatments, and specific anatomical considerations., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Sadu Singh et al.)

Obesity and type 2 diabetes mellitus (T2DM) is an alarming problem globally and a growing epidemic. Metabolic surgery has been shown to be successful in treating both obesity and T2DM, usually after other treatments have failed. This study aims to compare Roux-Y gastric bypass and sleeve gastrectomy in determining early diabetic outcomes in obese Malaysian patients with T2DM following surgery. A total of 172 obese patients with T2DM who were assigned to either laparoscopic Roux-en-Y gastric bypass (LRYGB) or laparoscopic sleeve gastrectomy (LSG) were analysed up to a year post-procedure. The patients' T2DM severity were stratified using the Individualized Metabolic Surgery (IMS) score into mild, moderate and severe. Remission rates of diabetes were compared between surgical techniques and within diabetic severity categories. T2DM remission for patients who underwent either surgical technique for mild, moderate or severe disease was 92.9%, 56.2% and 14.7% respectively. Both surgical techniques improved T2DM control for patients in the study. Comparing baseline with results 1 year postoperatively, median HbA1c reduced from 7.40% (IQR 2.60) to 5.80% (IQR 0.80) (p < 0.001), mean total antidiabetic medications use reduced from 1.48 (SD 0.99) to 0.60 (SD 0.86) [p < 0.001], insulin usage reduced from 27.9 to 10.5% (p < 0.001), and T2DM control improved from 27.9 to 82% (p < 0.001). The patients had a median excess BMI loss of 69.4% (IQR 34%) and 53.2% (IQR 36.0%) for RYGB and SG respectively (p = 0.016). At one year following surgery, there is no difference between LRYGB and LSG in terms of diabetic remission. LSG is not inferior to LRYGB in terms of early diabetic outcomes. Milder T2DM shows a better response. LSG is a simpler procedure with a lower risk profile and should be considered as an early treatment option for obese patients with T2DM., (© 2024. The Author(s).)

Study Objective: Sterile gloves are widely used during wound repair procedures in Emergency Departments (ED) worldwide. It is unclear whether sterile gloves protect against postoperative wound infections. We conducted a systematic review and meta-analysis to determine if sterile gloves offer significant protection against wound infections compared to clean gloves for wound repair in the ED., Methods: Ovid MEDLINE, Ovid Embase, Cochrane Library and Web Of Science were searched for randomised controlled trials (RCTs) or non-randomized studies of intervention (NRSIs) from their dates of inception to January 2023. RCTs or NRSIs comparing sterile (control) vs. clean/no (intervention) glove use for wound repair procedures in the ED and reporting postoperative wound infections were included. Two investigators independently extracted data and assessed risk-of-bias of each report on a standardised form. Wound infection incidence was pooled using a random effects model. Subgroup analysis was performed to explore heterogeneity., Results: 7 studies were included in the review, with 6 included in the meta-analysis. Of 3227 patients, 115/1608 (7.2%) patients in the intervention group and 135/1619 (8.3%) patients in the control group had postoperative wound infections. Overall RR was 0.86 (95% CI,0.67-1.10, I 2 =3.6%), and of high evidence certainty (GRADE). Absence of a protective effect was invariant in sensitivity analyses, leave-one-out analysis and subgroup analyses., Conclusion: No evidence of additional protection against wound infections with the use of sterile gloves for wound repair in the ED compared to clean gloves was found. However, the review was limited by nonreporting of antibiotic history and time between wound repair and follow-up amongst included studies. Considering the ergonomics, potential cost-savings and environmental impact, clean gloves are a viable alternative to sterile gloves, without compromising wound infection risk in this setting., Competing Interests: Declaration of Competing Interest None reported., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: Choice of ostomy appliances is based on multiple factors including economic considerations, individual patient requirements and lifestyle. A recently launched two-piece ostomy collection device with an extended tape border is expected to provide a long wear time and increase patients' sense of security., Aims and Methods: A randomised controlled, non-blinded, cross-over study involving 38 patients (with colostomies and ileostomies) compared the test device to a similar device from the same manufacturer but without the tape border. The main objective was to assess wear time for non-inferiority as a measure of efficacy. Secondary efficacy assessment included peristomal skin condition using the DET (discolouration, erosion and tissue growth) score and patient acceptability, which was assessed through questionnaires using Likert-scale options. Safety was assessed according to the incidence and intensity of device-related adverse events, and the condition of the peristomal skin., Results and Conclusion: Analysis of results in the per-protocol population showed an average wear time of 4.5 days for both devices and demonstrated non-inferiority. DET scores were similar in both groups, and both had low rates of device-related adverse events, all of which related to peristomal skin. Patients said the devices were user friendly. While the two devices are similar, some patients may find one with an adhesive tape more suited to their needs.

Background: Obesity is a growing health problem that has become a global epidemic. Serial population studies have shown the same in Malaysia, where the prevalence of obesity increased rapidly in the last decade. Currently, bariatric surgery is the most effective treatment in patients with morbid obesity. Obstructive sleep apnea (OSA) is the most common type of sleep-related breathing disorder seen in obesity., Objectives: We aim to ascertain the prevalence and severity of OSA in Asian patients who underwent bariatric surgery and were seen in our center., Setting: The study was conducted in our university hospital., Methods: Study approval was obtained from our institutional review board for a retrospective chart review. A total of 226 patients were included in this review. OSA was noted as absent or present and graded from mild to severe. The patient population was stratified by body mass index according to the World Health Organization guidelines for Asian population., Results: The overall sample prevalence of OSA was 80.5%. Of these, 24.3% had mild OSA, 23.9% had moderate OSA, and 32.3% had severe OSA. Only 17.3% have been diagnosed with OSA before bariatric workup. Among men, the prevalence of OSA was 93.7% and 75.5% among women., Conclusion: Based on these findings, Asian patients undergoing bariatric workup should be considered for routine polysomnography to enable treatment of OSA., (Copyright © 2020 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.)

Background: Gastrooesophageal reflux disease (GERD) is a spectrum of symptoms arising from the laxity of the cardio-oesophageal junction. Anti-reflux surgery is reserved for patients with refractory GERD. Anterior partial fundoplication (Dor) is a regularly performed anti-reflux surgery in Malaysia. We intend to determine the improvement in disease-specific quality of life in our patients after surgery., Methods: A multicentre cross-sectional study was conducted to assess patients' improvement in disease-specific quality of life after Dor fundoplication. Ethics approval was obtained from our institutional review board. Patients between the ages of 18 and 65 years who underwent Dor fundoplication within the past five years were assessed using the GERD HRQL as well as the VISICK score via telephone interview. We excluded cases of revision surgery., Results: Out of 129 patients screened, 55 patients were included. We found a significant improvement in patients' GERD HRQL score with the pre-operative mean score of 28.3 ± 9.39 and 6.55 ± 8.52 post-operatively, p  < 0.01.50.9% of patients reported a VISICK score of 1. However, we noticed a deterioration in the GERD HRQL and VISICK score in patients followed up four years after surgery. This consisted of 25.5% of total patients., Conclusion: Dor Fundoplication improves the overall disease-specific quality of life in patients with refractory GERD in the short term period. Recurrence of symptoms causing a deterioration in the quality of life is seen in patients followed up beyond four years of index surgery., Competing Interests: The authors declare that they have no conflict of interest., (© 2020 The Authors.)

Kidney dysfunction, a deleterious effect of obesity, is now recognized as a relevant health risk. Chemokine (C-C Motif) Ligand 2 (CCL2) is one of the critical chemokines that play a vital role in the development of obesity-related metabolic disease. We aim to measure the changes in urinary CCL2 in our patients before and after their bariatric procedure and examine the correlation between CCL2 and renal function. A prospective cohort study was conducted at our teaching university hospital. Ethics approval was obtained from our institutional review board. Patients with a BMI of ≥37.5 kg/m 2 with no history of renal disease were included. They underwent single anastomosis gastric bypass (SAGB), Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG), all performed via laparoscopic approach. Venous blood and urine samples were obtained preoperatively and six months after surgery. A total of 58 patients were recruited, with SG being performed in 74.1% of patients. At six-months follow-up, median (IQR) body weight reduced from 101.35 kgs (20.25) to 76.95 kg (24.62) p < 0.001. The mean (SD) estimated glomerular filtration rate (eGFR) improved from 96.26 ± 14.97 to 108.06 ± 15.00 mL/min/1.73 m 2 , p < 0.001. The median (IQR) urinary CCL2 levels reduced from 15.2 pg/ml (10.77) to 4.30 pg/ml (4.27) p < 0·001. There is a significant correlation between the reduction of BMI and the reduction of urinary CCL2 (r = -0.220, p = 0.048). We also found a significant correlation between the reduction of urinary CCL2 with the reduction of urine ACR (r = -0.240, p = 0.035). Urinary CCL2 is a promising biomarker that can be used to assess improvement in renal function in obese patients after bariatric surgery.

Acute airway obstruction in pregnancy remains a challenge to manage. Failure of appropriate and timely airway management may lead to maternal morbidity and mortality such as aspiration pneumonitis or worst hypoxaemic cardiopulmonary arrest. 1 As pregnancy may exacerbate asthma attacks, parturient presenting with wheezing or shortness of breath will commonly be treated as suffering from an asthmatic attack. 2 However, it is important to note other possible differential diagnoses. Thyroid disease is relatively common in women of childbearing age. The thyroid gland undergoes several changes during pregnancy, which may lead to altered function as well as gland enlargement and cause upper airway obstruction and symptoms similar to a bronchial asthma attack. 3 4 With that in mind, we report a case of a parturient with long-standing goitre in her second trimester who presented to our institution with acute respiratory symptoms and cardiopulmonary arrest., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

There is an increasing trend in the number of bariatric surgeries performed worldwide, partly because bariatric surgery is the most effective treatment for morbid obesity. Sleeve gastrectomy (SG) remains the most common bariatric surgery procedure performed, representing more than 50% of all primary bariatric interventions. Major surgical complications of SG include staple-line bleeding, leaking, and stenosis. A leak along the staple-line most commonly occurs at the gastroesophageal junction (GOJ). From January 2018 to December 2018, our centre performed 226 bariatric procedures, of which, 97.8% were primary bariatric procedures. The mean age and BMI were 38.7±8.3 years and 44 kg/m2, respectively. Out of the 202 primary SG performed, we encountered two cases of a staple-line leak (0.99%). This is the first reported case series of SG leaks from the Southeast Asia region. A summary of their characteristics, clinical presentation, subsequent management, and the outcome is discussed. Based on the latest available evidence from the literature, several methods may decrease staple-line leaks in SG. These include the use of a bougie size greater than 40 Fr, routine use of methylene blue test during surgery, beginning transection at 2-6 cm from the pylorus, mobilising the fundus before transection, and staying away from the GOJ at the last firing. Other methods include the proper alignment of the staple-line, control of staple-line bleeding, and performing staple-line reinforcement. The management of a staple-line leak remains challenging due to limited systematic, evidence-based literature being available. Therefore, a tailored approach is needed to manage this complication.

A biliary fistula which may occur spontaneously or after surgery, is an abnormal communication from the biliary system to an organ, cavity or free surface. Spontaneous biliary-enteric fistula is a rare complication of gallbladder pathology, with over 90% of them secondary to cholelithiasis. Approximately 6% are due to perforating peptic ulcers. Symptoms of biliary-enteric fistula varies widely and usually non-specific, mimicking any chronic biliary disease. Cholecystoduodenal fistula causing severe upper gastrointestinal (UGI) bleed is very rare. Bleeding cholecystoduodenal fistula commonly requires surgical resection of the fistula and repair of the duodenal perforation. We describe the case of a previously healthy older patient who initially presented with symptoms suggestive of UGI bleeding. Bleeding could not be controlled endoscopically. When a laparotomy was performed, a cholecystoduodenal fistula was discovered and bleeding was noted to originate from the superficial branch of cystic artery., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: Transoesophageal echocardiography (TOE) is a widely used intraoperative diagnostic tool in cardiac patients, and it is considered as a safe and non-invasive procedure. However, it has its known complications, which is estimated to be 0.18% with mortality reported as 0.0098%. Complications of TOE include odynophagia, upper gastrointestinal haemorrhage, endotracheal tube malpositioning and dental injury. One of the rarer complications includes oesophageal perforation, whose incidence is reported to be 0.01%., Case Presentation: We present a case of a 61-year-old lady with mitral valve prolapse (MVP) who underwent TOE with subsequent presentation of odynophagia with left neck swelling. An upper endoscopy examination was inconclusive; however, a contrasted computed tomography of the neck showed evidence of cervical oesophageal perforation. She was managed conservatively and discharged well., Discussion: The trauma caused by TOE probe insertion and manipulation accounts for most of the upper gastrointestinal complications. Mortality of patients associated with oesophageal perforation can be up to 20% and doubled if the treatment is delayed for more than 24 h. Mechanism of injury from TOE probe is likely multifactorial. Predisposing factors that increase the risk of tissue disruption include the presence of unknown structural pathology. Imaging studies and an upper endoscopy examination may aid in the diagnosis of oesophageal perforation., Conclusion: A high index of suspicion, coupled with a tailored, multidisciplinary approach, is essential to achieve the best possible outcome. Conservative management may be worthwhile in a stable patient despite delayed presentation. Although TOE is considered a safe procedure, physicians should be made aware of such a dreaded complication., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Introduction: Gastrointestinal stromal tumours (GISTs) are the most common mesenchymal neoplasms of the alimentary tract but accounts for only 0.1-3% of all gastrointestinal neoplasms. The most common presentation of GISTs is acute or chronic gastrointestinal bleeding, in which the patient presents with symptomatic anaemia., Presentation of Case: With that in mind, we describe a 66-year-old man who presented with recurrent episodes of obscure gastrointestinal bleeding for two years. Video capsule endoscopy (VCE) showed several small telangiectasias in the proximal small bowel. Oral route double-balloon enteroscopy (DBE) revealed abnormal mucosa 165 cm from incisor with central ulceration and vascular component. He subsequently underwent surgical excision. The histopathological report confirmed the diagnosis of GIST arising from the jejunum. During his clinic follow up, he remains symptom-free with no evidence of recurrence., Discussion: The diagnosis of bleeding small intestine GISTs can be challenging as these are inaccessible by conventional endoscopy. Imaging modalities such as double-balloon enteroscopy, capsule endoscopy, CT angiography, intravenous contrast-enhanced multidetector row CT (MDCT) and magnetic resonance enterography (MRE) have been used to assist in the diagnosis of bleeding small intestine GISTs. The mainstay of management for small intestine GIST is complete surgical excision., Conclusion: Bleeding jejunal GIST is very rare and only a handful of case reports have been published. The mainstay of management for small intestine GIST is complete surgical excision. It is essential to obtain a complete excision of localised disease and avoiding tumour spillage in order to reduce the risk of local recurrence and metastatic spread of GISTs., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Introduction: Primary fascial closure can be a challenging step during a laparoscopic intraperitoneal onlay mesh (IPOM) repair for a ventral hernia., Case Presentation: We present here a novel technique of using intravenous (IV) cannula as an alternative to suture passer for fascial closure during laparoscopic IPOM repair for a 59-year-old patient with an incisional ventral hernia. The placement of non-absorbable sutures for fascial closure was done with the help of a 14 gauge IV cannula instead of a transfascial suture passer. The rest of the procedural steps were the same as a standard laparoscopic IPOM repair. The patient's post-operative recovery was uneventful., Discussion: Primary fascial closure during a laparoscopic IPOM hernia repair can be done either by intracorporeal or extracorporeal techniques, using interrupted or continuous sutures. We propose a novel alternative to suture passer in primary fascial closure. IV cannulas are widely available in hospital settings. The advantage of using an IV cannula instead of a suture passer is that they are widely available. Its single-use also eliminates the risk of transmissible diseases, and as it has a smaller diameter than suture passer, it requires a lower insertion force for successful placement., Conclusion: An IV cannula may be used as a more economical alternative to a transfascial suture passer. This technique is easily reproducible and does not violate the principles of primary fascial defect closure in laparoscopic ventral hernia repair., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Barium enema investigation is regarded as a safe investigative procedure. Rarely, it may cause complications such as colonic perforation and barium intravasation. Barium intravasation may be caused by the inadvertent introduction of the catheter into the vagina, thereby into the vaginal venous plexus. It may also occur through mechanical colonic perforation with the catheter, or via diseased bowel conditions. This may lead to complications such as liver microabscesses, massive pulmonary embolism, hypovolemic shock, disseminated intravascular coagulopathy and even sudden death. With that in mind, we would like to report an interesting case of barium intravasation into the portal venous system via the vagina venous plexus. The patient experienced abdominal discomfort with mild per vaginal bleed and went into disseminated intravascular coagulopathy. She received supportive management and she made a full recovery.

Peroxiredoxin 1 (Prx 1), also known as natural killer enhancing factor A (NKEF A), has been implicated in the immune response of both mammals and fish. Amoebic gill disease (AGD), caused by Neoparamoeba perurans, is a significant problem for the Atlantic salmon (Salmo salar L.) aquaculture industry based in Tasmania, Australia. Here we have cloned and functionally characterized a Prx 1 open reading frame (ORF) from Atlantic salmon liver and shown that Prx 1 gene expression was down-regulated in the gills of Atlantic salmon displaying symptoms of AGD. The Prx 1 ORF encoded all of the residues and motifs characteristic of typical 2-Cys Prx proteins from eukaryotes and the recombinant protein expressed in Escherichia coli catalyzed thioredoxin (Trx)-dependent reduction of H(2)O(2), cumene hydroperoxide (CuOOH) and t-butyl hydroperoxide (t-bOOH) with K(m) values of 122, 77 and 91 μM, respectively, confirming that it was a genuine 2-Cys Prx. The recombinant protein also displayed a double displacement reaction mechanism and a catalytic efficiency (k(cat)/K(m)) with H(2)O(2) of 1.5 × 10(5) M(-1) s(-1) which was consistent with previous reports for the 2-Cys Prx family of proteins. This is the first time that a Prx 1 protein has been functionally characterized from any fish species and it paves the way for further investigation of this important 2-Cys Prx family member in fish., (Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.)

Peroxiredoxins (Prxs) are antioxidant enzymes with a conserved Cys residue at the active site which undergoes peroxide-dependent oxidation followed by thiol-dependent reduction during each catalytic cycle. In mammals, Prx 4 proteins have an N-terminal signal peptide which targets them for secretion from the cell. This has not been investigated in fish. Thus, here we describe the cloning of a Prx 4 cDNA from yellowtail kingfish (YTK, Seriola lalandi) and the elucidation of the signal peptide cleavage site. The YTK Prx 4 cDNA included a 792bp open reading frame (ORF) encoding a predicted protein of 264 amino acids (referred to as Prx264). SignalP software and a multiple sequence alignment predicted signal peptide cleavage sites after residues 33 and 67 giving rise to Prx231 and Prx197, respectively. All three proteins were expressed in E. coli and assayed for thioredoxin-dependent peroxidase activity. Prx231 and Prx197 both exhibited activity whereas Prx264 did not. Thus, either potential cleavage site may be physiologically relevant. Both active forms of the enzyme displayed a single-displacement reaction mechanism and typical saturable Michaelis-Menten type kinetics. This is unusual for Prx enzymes. In addition, they both displayed a clear preference for H(2)O(2) over cumene hydroperoxide or t-butyl hydroperoxide., (2010. Published by Elsevier Inc. All rights reserved.)

Peroxiredoxins (Prxs, EC: 1.11.1.15) are cysteine-dependent peroxidases proposed to function as antioxidant enzymes and also in H2O2-mediated cell signaling. They have been well characterized in yeast, mammals, protists and bacteria but not yet in fish. Here we describe the cloning and functional characterization of a Prx 2 cDNA from southern bluefin tuna (SBT, Thunnus maccoyii), an important aquaculture species in South Australia. The SBT Prx sequence was closely related (76-92% identical) to Prx 1 and 2 sequences from other fish and mammals and phylogenetic analyses showed that it was most likely a Prx 2. The deduced amino acid sequence contained the peroxidatic and resolving Cys residues characteristic of typical 2-Cys Prx proteins from all kingdoms of life. It also contained the GGLG motif associated with the sensitivity of eukaryotic typical 2-Cys Prx proteins to overoxidation and consequent inactivation by H2O2. When the SBT Prx 2 was expressed in E. coli, it showed thioredoxin (Trx)-dependent peroxidase activity with H2O2, cumene hydroperoxide (CuOOH) and t-butyl hydroperoxide (t-bOOH). The SBT Prx displayed Michaelis-Menten kinetics with Trx but sigmoidal kinetics with H2O2 and CuOOH. The K(m)(Trx) was 12 microM and the S(0.5) values for H2O2 and CuOOH were 29 and 25 microM, respectively. At mM concentrations of H2O2, SBT Prx progressively lost its peroxidase activity as has been observed for other eukaryotic typical 2-Cys Prx proteins. The native SBT Prx enzyme existed as a mixture of dimers, tetramers, decamers and a higher order aggregate., (2010 Elsevier Inc. All rights reserved.)