Jose Manuel Ramirez

Protective effects of melatonin in reducing oxidative stress and in preserving the fluidity of biological membranes: a review

Free radicals generated within subcellular compartments damage macromolecules which lead to severe structural changes and functional alterations of cellular organelles. A manifestation of free radical injury to biological membranes is the process of lipid peroxidation, an autooxidative chain reaction in which polyunsaturated fatty acids in the membrane are the substrate. There is considerable evidence that damage to polyunsaturated fatty acids tends to reduce membrane fluidity. However, adequate levels of fluidity are essential for the proper functioning of biological membranes. Thus, there is considerable interest in antioxidant molecules which are able to stabilize membranes because of their protective effects against lipid peroxidation. Melatonin is an indoleamine that modulates a wide variety of endocrine, neural and immune functions. Over the last two decades, intensive research has proven this molecule, as well as its metabolites, to possess substantial antioxidant activity. In addition to their ability to scavenge several reactive oxygen and nitrogen species, melatonin increases the activity of the glutathione redox enzymes, that is, glutathione peroxidase and reductase, as well as other antioxidant enzymes. These beneficial effects of melatonin are more significant because of its small molecular size and its amphipathic behaviour, which facilitates ease of melatonin penetration into every subcellular compartment. In the present work, we review the current information related to the beneficial effects of melatonin in maintaining the fluidity of biological membranes against free radical attack, and further, we discuss its implications for ageing and disease.

Local full-thickness excision as first line treatment for sessile rectal adenomas: long-term results.

Objective:Removing rectal adenomas not only relieves symptoms, but also eradicates the incidence of carcinoma. There are many techniques for local removal of rectal polyps. Transanal endoscopic microsurgery (TEM) is the most recent. The purpose of this study is to present our long-term results using TEM for rectal adenomas, paying special attention to the risk factors of harboring a malignancy. Methods:Data from all patients undergoing TEM from December 1995 to December 2005 were collected prospectively. The selection criteria were benign sessile adenomas below the peritoneal reflection. In the study period, 173 patients were operated on for an apparently benign rectal adenoma. The mean distance of lower tumor was 7.6 cm (range, 1–18 cm), and the mean distance to upper edge was 11 cm (2–20 cm). Full-thickness local excision was performed in all procedures. Patients were followed for a minimum of 1 year. Results:According to the histologic findings, 14% of the specimens were invasive carcinomas. No statistical differences were found when comparing the histologic findings by tumor size, distance to the anal verge, or location. In 10 (5.8%) cases, the dissection was considered uncompleted because of a normal mucosa margin smaller than 1 mm. The mean hospital stay was 4 days (2–30 days). The morbidity rate was 14.5%. There was 1 postoperative death (0.6%). There were 9 (5.4%) histologically proven recurrences. Four of the patients with recurrence had uncompleted microscopic circumferential resection (P = 0.001). At a mean follow-up of 35 months (range, 12–82 months), all carcinoma patients were alive with no evidence of disease. Conclusions:In conclusion, a significant number of adenomas that we assumed preoperatively to be benign were already carcinomas and we were unable to find any reliable predictor to identify them. TEM full-thickness excision provided a low rate of postoperative morbidity and potentially avoided a significant number of major abdominal operations and local recurrences.

Melatonin role preventing steatohepatitis and improving liver transplantation results

Liver steatosis is a prevalent process that is induced due to alcoholic or non-alcoholic intake. During the course of these diseases, the generation of reactive oxygen species, followed by molecular damage to lipids, protein and DMA occurs generating organ cell death. Transplantation is the last-resort treatment for the end stage of both acute and chronic hepatic diseases, but its success depends on ability to control ischemia–reperfusion injury, preservation fluids used, and graft quality. Melatonin is a powerful endogenous antioxidant produced by the pineal gland and a variety of other because of its efficacy in organs; melatonin has been investigated to improve the outcome of organ transplantation by reducing ischemia–reperfusion injury and due to its synergic effect with organ preservation fluids. Moreover, this indolamine also prevent liver steatosis. That is important because this disease may evolve leading to an organ transplantation. This review summarizes the observations related to melatonin beneficial actions in organ transplantation and ischemic–reperfusion models.

Current Controversies in Transanal Surgery for Rectal Cancer.

Local surgery for rectal tumors has been traditionally limited due to technical issues for lower risk lesions. In the 1980s, Buess described the transanal endoscopic microsurgery (TEM) technique that enabled excision of lesions that were larger and in a higher location. TEM in a short time became the gold standard for the excision of large adenomas and early rectal carcinomas. Since the advent of TEM, and due to advances in minimal invasive technology, new devices and procedures have come to the surgical armamentarium, in many cases with only very slight differences between them. However, local surgery for rectal cancer still remains a challenge. An overview of the current status of minimal transanal invasive techniques is presented here and sheds some light on the controversies that the local management of rectal cancer still raises.

Implementation of the Spanish ERAS program in bariatric surgery

Abstract Introduction: The essence of Enhanced Recovery After Surgery (ERAS) programs is the multimodal approach, and many authors have demonstrated safety and feasibility in fast track bariatric surgery. According to this concept, a multidisciplinary ERAS program for bariatric surgery has been developed by the Spanish Fast Track Group (ERAS Spain). The aim of this study was to analyze the initial implementation of this Spanish National ERAS protocol in bariatric surgery, comparing it with a historical cohort receiving standard care. Material and methods: A multi-centric prospective study was performed, including 233 consecutive patients undergoing bariatric surgery during 2015 and following ERAS protocol. It was compared with a historical cohort of 286 patients, who underwent bariatric surgery at the same institutions between 2013 and 2014 and following standard care. Compliance with the protocol, morbidity, mortality, hospital stay and readmission were evaluated. Results: Bariatric techniques performed were Roux-en-Y gastric bypass and sleeve gastrectomy. There were no significant differences in complications, mortality and readmission. Postoperative pain and hospital stay were significantly lower in the ERAS group. The total compliance to protocol was 80%. Conclusion: The Spanish National ERAS protocol is a safe issue, obtaining similar results to standard care in terms of complications, reoperations, mortality and readmissions. It is associated with less postoperative pain and earlier hospital discharge.

Implementation of the Spanish National Enhanced Recovery Program (ERAS) in Bariatric Surgery: A Pilot Study.

Introduction: The essence of Enhanced Recovery After Surgery (ERAS) programs is the multimodal approach, and many authors have demonstrated safety and feasibility in fast track bariatric surgery. According to this concept, a multidisciplinary ERAS program for bariatric surgery has been developed by the Spanish fast track group (ERAS Spain). The aim of this study was to analyze the initial implementation of this Spanish National ERAS protocol in bariatric surgery. Patients and Methods: A multicentric prospective pilot study was performed, including 125 consecutive patients undergoing bariatric surgery at 3 Spanish hospitals between January and June 2015, after the Spanish National ERAS protocol in bariatric surgery. Compliance with the protocol, morbidity, mortality, hospital stay, and readmission were evaluated. Results: Bariatric techniques performed included 68 Roux-en-Y gastric bypass (54.4%) and 57 laparoscopic sleeve gastrectomy (45.6%) cases. All surgeries were laparoscopically performed with conversion in only 1 case (0.8%). Median postoperative pain evaluated by visual analogic scale 24 hours after surgery was 2 (range, 0 to 5). Postoperative nausea or vomiting appeared in 7 patients (5.6%). Complications appeared in 6 patients (4.8%). The reoperation rate was 4%. The mortality rate was 0.8%. The median hospital stay was 2 days (range, 2 to 10 d) and readmission rate was 2.4%. The compliance of all the items of the protocol was achieved in 78.4% of the patients. Conclusions: The Spanish National ERAS protocol is a safe issue with a high implementation rate. It can be recommended to establish this protocol to other institutions.