Bariatric reduction system - BARS: device, technique and first clinical experience.

BACKGROUND: Roux-en-Y gastric by-pass (RYGB) is one of the most effective bariatric procedures, but the rate of weight regain (WR) can reach 63% after the second year. Enlargement of the gastrojejunal anastomosis is one of the reported causes. A newly CE-marked flexible endoscopic system, Bariatric Anastomotic Reduction System (BARS) (Ovesco Endoscopy, Tuebingen, Germany), derivative of the well-established endoscopic over-the-scope-clip (OTSC) clipping system, has been recently developed. It was tested in pre-clinical and preliminary clinical use for feasibility and effectiveness in bariatric anastomotic reduction. MATERIAL AND METHODS: Using a single-channel endoscope with external supplemental working channel, the BARS device captures the two limbs of the anastomosis, reducing its size, thus slowing food passage. After preclinical assessment, six patients with at least a 15% WR and the presence of an enlarged gastrojejunostomy > 20 mm were enrolled. The mean patient age was 49 years (range 24-67). Average interval between gastric bypass and BARS procedure: 8 years (4-13). RESULTS: All procedures were safely performed without complications. Mean procedure time: 52 min (37 - 75). Preliminary results: mean weight loss 6 kg (4-9) at a 3-month FU. CONCLUSIONS: BARS could be a promising endoscopic system in case of WR after gastric bypass due to enlargement of the anastomosis.

Pre-clinical study on a telemetric gastric sensor for recognition of acute upper gastrointestinal bleeding: the "HemoPill monitor".

BACKGROUND: Acute upper gastrointestinal bleeding is a life-threatening medical condition with a relevant risk of re-bleeding even after initial endoscopic hemostasis. The implantable HemoPill monitor contains a novel telemetric sensor to optically detect blood in the stomach allowing the surveillance of high-risk patients for re-bleedings. METHODS: In this pre-clinical porcine study, bleeding has been simulated by injecting porcine blood into the stomach of a pig through an implanted catheter using a syringe pump. The effect of the sensor position in the stomach, the gastric food content, and the bleeding intensity was investigated. RESULTS: Sensitivity and specificity of the sensor reached more than 87.5% when the sensor was positioned close to the source of bleeding. Solid food had a higher negative impact on sensitivity than liquid food but a positive impact on specificity. A heavy bleeding was more likely to be detected by the sensor but was also associated with a lower likelihood for true-negative results than weaker bleedings. CONCLUSIONS: The study clearly demonstrated the capability of the HemoPill sensor prototype to detect clinically relevant bleedings with high sensitivity and specificity (> 80%) when the sensor was positioned close to the bleeding site. The sensors proved to be robust against artefact effects from stomach content. These are favorable findings that underline the potential benefit for the use of the HemoPill sensor in monitoring patients with a risk of re-bleeding in the upper gastrointestinal tract.

Efficacy of the OTSC System in the treatment of GI bleeding and wall defects: a PMCF meta-analysis.

Since its market launch in 2007, the endoscopic OTSC clipping system has been the object of intensive clinical research. These data were systematically collected for post-market clinical follow-up (PMCF). The aim of the study was the systematic review of the efficacy and safety of the OTSC System. The PMCF database was systematically searched for clinical data on OTSC therapy of GI hemorrhage (H), acute leaks/perforations (AL) and chronic leaks/fistulae (CL). Major outcomes were successful clip application and durable hemostasis/closure of defects. Comprehensive pooled success proportions were established by meta-analytical methods. Four-hundred-fifty-seven publications were reviewed. Fifty-eight articles comprising 1868 patients fulfilled criteria to be included in the analysis. These consisted of retrospective analyses, prospective observational trials, one randomized-controlled trial (STING) and one quasi-controlled study (FLETRock). The pooled proportion analysis revealed high overall proportions of technical success: H - mean 93.0% [95%CI 90.2-95.4], AL-mean 89.7% [95%CI 85.9-92.9] and CL-mean 83.8% [95%CI 76.9-89.7]. Pooled durable clinical success proportions were: H-mean 87.5% [95%CI 80.5-93.2], AL-mean 81.4% [95%CI 77.0-85.3] and CL-mean 63.0% [95%CI 53.0-72.3]. By pooling all clinical data gained, we conclude that OTSC application in GI hemorrhage and closure of GI lesions is safe and effective in real clinical use.

Preclinical evaluation of a novel thermally sensitive co-polymer (LiftUp) for endoscopic resection.

Introduction: Endoscopic resection techniques can successfully resect large lesions either in "en bloc" fashion or in "piece-meal" technique by using a submucosal injection solution. The aim of this study was to evaluate the safety of a novel injectable, containing thermally sensitive co-polymer from ethylenoxide and propylenoxide (LiftUp) used as submucosal injection solution.Material and methods: We conducted an in vivo animal trial in the porcine model to evaluate the LiftUp gel in a preclinical setting and to study the effectiveness of mucosal lifting and the safety of the new injectable. In seven animals a total of 63 injections and endoscopic resections were carried out in different anatomical locations (esophagus, stomach and rectum). The resection sites were controlled endoscopically one and four weeks after resection and a histopathological evaluation of the resection sites was performed after four weeks.Results: The application of LiftUp was safe and there were no negative effects on wound healing after injection and resection. A major procedural complication rate (defined as perforation and major haemorrhage) of 3.2% was registered, which undercuts the anticipated mean complication rate of 4-8%. Furthermore, there was no necessity of reinjection after the initial submucosal injection in 90.5% and no procedural complications in 98.8%. The histopathological examination of the tissue samples indicated normal wound healing with granulation tissue and epithelialisation.Conclusion: The use of LiftUp as submucosal injection solution was feasible for different endoscopic resection techniques, with high and long-lasting elevation and fewer procedural adverse events than expected at trial planning. The new injectable is a practical advancement over the current state-of-the-art of submucosal injection and could fasten up the resection procedure and make endoscopic 'en bloc' resection safer.

Efficacy and safety of the remOVE System for OTSC® and FTRD® clip removal: data from a PMCF analysis.

INTRODUCTION: The remOVE System (Ovesco Endoscopy AG, Tuebingen, Germany) is a medical device for the endoscopic removal of OTSC or FTRD clips (Ovesco Endoscopy AG, Tuebingen, Germany). The aim of this paper is to assess the efficacy and safety of this system. MATERIAL AND METHODS: A total of 74 patients underwent clip extraction. The standard removal procedure comprises fragmenting the clip by applying an electrical direct current pulse at two opposing sides of the clip. RESULTS: Clip fragmentation was successful in 72 of 74 patients (97.3%). In two cases (2.7%) clip fragmentation was not possible. In nine cases (12.2%) a clip fragment could not be removed and was left in place. Complications occurred in three cases (4.1%): two minor bleedings near the clip removal site (2.7%), and one superficial mucosal tear resulting from clip fragment extraction (1.4%). DISCUSSION: Based on this study, the use of the remOVE System for OTSC or FTRD clip removal can be considered safe and effective.

Volunteer Case Series of a New Telemetric Sensor for Blood Detection in the Upper Gastrointestinal Tract: The HemoPill.

BACKGROUND: An acute upper gastrointestinal bleeding event is an emergency situation which requires immediate endoscopic assessment and treatment. A new telemetric real-time intracorporeal bleeding sensor can help in the timely diagnosis of an acute upper gastrointestinal bleeding event: The sensor capsule, HemoPill, is swallowed by the patient if gastrointestinal bleeding is suspected. Information about the bleeding status is displayed by telemetric communication of the capsule with an extracorporeal receiver. This is the first evaluation of the HemoPill to detect blood in the upper human gastrointestinal tract. METHODS: A voluntary test person ate a defined meal with or without the adjunct of his own blood for a total of eight times and afterward swallowed the sensor capsule. The collected spectrometric receiver data were analyzed to assess whether the sensor system was capable of detecting blood and to evaluate the effect of stomach content as an artifact. RESULTS: With its optical sensor, the HemoPill was able to reliably indicate the ingested blood in the stomach. The data transmission from the swallowed sensor capsule to the extracorporeal receiver was achieved consistently. The evaluation of diverse concentrations of ingested blood and the respective sensor signals led to an exponential relationship of these variables. This relationship allows to define thresholds for categories indicating the likelihood of blood presence in the gastrointestinal tract. CONCLUSIONS: The HemoPill is a valuable tool to detect an acute upper gastrointestinal bleeding event without the need of endoscopy.

Porcine survival model to simulate acute upper gastrointestinal bleedings.

The existing animal models used for the simulation of acute gastrointestinal bleedings are usually non-survival models. We developed and evaluated a new porcine model (domestic pig, German Landrace) in which the animal remains alive and survives the artificial bleeding without any cardiovascular impairment. This consists of a bleeding catheter which is implanted into the stomach, then subcutaneously tunnelled from the abdomen to the neck where it is exteriorized and fixed with sutures. Using the injection of porcine blood, controllable and reproducible acute upper gastrointestinal bleeding can be simulated while maintaining normal gastrointestinal motility and physiology. Depending on the volume of blood applied through the gastric catheter, the bleeding intensity can be varied from traces of blood to a massive haemorrhage. This porcine model could be valuable, e.g. for testing the efficacy of new bleeding diagnostics in large animals before human use.

Telemetric real-time sensor for the detection of acute upper gastrointestinal bleeding.

Acute upper gastrointestinal bleedings from ulcers or esophago-gastric varices are life threatening medical conditions which require immediate endoscopic therapy. Despite successful endoscopic hemostasis, there is a significant risk of rebleeding often requiring close surveillance of these patients in the intensive care unit (ICU). Any time delay to recognize bleeding may lead to a high blood loss and increases the risk of death. A novel telemetric real-time bleeding sensor can help indicate blood in the stomach: the sensor is swallowed to detect active bleeding or is anchored endoscopically on the gastrointestinal wall close to the potential bleeding source. By telemetric communication with an extra-corporeal receiver, information about the bleeding status is displayed. In this study the novel sensor, which measures characteristic optical properties of blood, has been evaluated in an ex-vivo setting to assess its clinical applicability and usability. Human venous blood of different concentrations, various fluids, and liquid food were tested. The LED-based sensor was able to reliably distinguish between concentrated blood and other liquids, especially red-colored fluids. In addition, the spectrometric quality of the small sensor (size: 6.5mm in diameter, 25.5mm in length) was comparable to a much larger and technically more complex laboratory spectrophotometer. The experimental data confirm the capability of a miniaturized sensor to identify concentrated blood, which could help in the very near future the detection of upper gastrointestinal bleeding and to survey high-risk patients for rebleeding.

Endoscopic full-thickness resection and clip defect closure in the colon with the new FTRD system: experimental study.

BACKGROUND: The benefit of endoscopic full-thickness resection is the improved diagnostic work-up with an integral wall specimen which allows a precise determination of the tumor or its precursor and its infiltration depth into the wall. MATERIALS AND METHODS: A new endoscopic full-thickness resection device (FTRD), which is a combination of a modified over-the-scope-clip (OTSC) system with an electrocautery snare, has been tested in an experimental setting. In eleven pigs, divided into three groups, endoscopic full-thickness resection was performed in the colon at one or two sites, respectively. Seven days (n = 7) or 28 days (n = 4) after the intervention, the animals were euthanized following endoscopic examination of the resection and clip application sites. Furthermore, two different clips were tested during these animal trials in order to evaluate the most effective clip design. RESULTS: The average diameter of the tissue resected with the FTRD was 3.1, 3.6, and 5.4 cm in the three groups. On follow-up endoscopy 7 days after the intervention, fibrin coating and stool residues were found at all clips, causing minor inflammatory reactions. However, the colon wall under the clip was non-inflamed. After 28 days, the serosa had primarily healed in all cases. There were also stool residues at all clips; however, no acute inflammatory reactions were seen anymore, due to complete healing. Histological assessment did not show any signs of dehiscence in the region of the scar, or ischemia in the clip area. In addition, no wound infections, such as abscess formation, were observed. CONCLUSIONS: This study demonstrates the safety and efficacy of the clip-and-cut technique using the new FTRD system. With the device, a local full-thickness colon resection can be easily created, and the resulting wall defect is reliably sealed by the endoluminal application of a modified OTSC clip.

Annulated and bridged tetrahydrofurans from alkenoxyl radical cyclization.

4-Pentenoxyl radicals sharing two or more carbon atoms with a cycloalkane cyclize in a predictable manner stereoselectively and regioselectively to afford in solutions of bromotrichloromethane cycloalkyl-fused or -bridged 2-bromomethyltetrahydrofurans in up to 95% yield. Stereoselectivity in alkenoxyl radical ring closures arises from cumulative steric effects. The substituent positioned the closest to the alkene carbon, which is being attacked by the oxygen radical, exerts the strongest stereodirecting effect. This principal inductor guides 5-exo-cyclization 2,3-trans- or 2,4-cis-selectively. The substituent located further from the attacked π-bond is the secondary inductor. A secondary inductor in the relative trans-configuration enhances stereodifferentiation by the primary inductor; a cis-configured secondary inductor decreases this effect. A secondary inductor is not able to overrule the guiding effect of a similar sized primary inductor. Intramolecular 4-pentenoxyl radical additions to a cyclohexene-bound exo-methylene group or to endocyclic double bonds proceed cis-specifically, as exemplified by synthesis of a diastereomerically pure bromobicyclo[2.2.1]heptyl-annulated tetrahydrofuran from the verbenylethyloxyl radical. According to theory, the experimental 2,3-cis-specificity in alkoxyl radical cyclization to an endocyclic π-bond arises from strain associated with the 2,3-trans-ring closure.

Performance of the OTSC System in the endoscopic closure of iatrogenic gastrointestinal perforations: a systematic review.

BACKGROUND: Reliable closure is a prerequisite for conventional and innovative endoscopic procedures, such as NOTES. The purpose of this study is the systematic evaluation of the procedural and clinical success rates in closure of iatrogenic gastrointestinal perforations and acute anastomotic leaks by means of the over-the-scope-clip system (OTSC(®)). DESIGN: PubMed and other sources were searched systematically for clinical and preclinical research on the evaluation of the OTSC System for closure of gastrointestinal perforations and leaks. Appraisal of studies for inclusion and data extraction was performed independently by two reviewers using an a priori determined data extraction grid. Major endpoints to be extracted were data on procedural success (successful clip application) and clinical access (durable closure of defect without secondary adjunct therapy). RESULTS: A total of 17 clinical research articles/abstracts and 22 preclinical research articles/abstracts were identified. The examined clinical studies comprised case series and clinical single-arm studies. The reviewed studies revealed a consistently high mean rate of procedural success of 80-100 % and durable clinical success of 57-100 %. An identified major drawback preventing successful clip application was occurrence of fibrotic or inflamed lesion edges. Usage of the OTSC System was accompanied by neither major clip-related nor application-related complication. In experimental settings, closure of larger perforations and gastric access sites of NOTES or endoscopic full-thickness resection were achieved with high rates of success. CONCLUSIONS: Because randomized, clinical trials are not available in this field of indication, the evaluation is based on small case series. Nevertheless, by pooling all experience gained, we conclude that endoscopic closure of iatrogenic gastrointestinal perforations and acute anastomotic leaks by means of the OTSC System is a safe and effective method.

Performance of the OTSC System in the endoscopic closure of gastrointestinal fistulae--a meta-analysis.

BACKGROUND: Conventional endoscopic treatment options for closure of gastrointestinal fistulae are impaired by several limitations and therefore yield high rates of recurrence. Aim of the study is the evaluation of the primary-technical and secondary-clinical success rates in closure of gastrointestinal fistulae by means of the OTSC System. DESIGN/METHODS: The database Medline was systematically searched for primary research on the evaluation of the OTSC System in closure of gastrointestinal fistulae. Appraisal of studies for inclusion and data extraction were performed independently by two reviewers using an a priori determined data extraction grid. RESULTS: A total of 19 primary research articles were identified. The examined studies comprised case reports as well as case series and clinical single-arm studies (n = 7) with a limited number of participants. Reviewed studies revealed a high rate of procedural success (mean 84.6%; 95% confidence interval 66.6 to 93.8%) and durable clinical success (mean 69.0%; 95% confidence interval 51.8 to 82.2%). Failed attempts and incomplete closures were mainly ascribed to the challenging effort of treating highly fibrotic chronic fistulae. CONCLUSION: Endoscopic closure of gastrointestinal fistulae by means of the OTSC System is a safe and effective method.

Endoluminal full-thickness resection of GI lesions: a new device and technique.

Full-thickness resection techniques are of growing interest in the field of endoscopic removal of tumors or their precursors in the digestive tract. A new dedicated full-thickness resection device has been developed based on the combination of the OTSC clip, an enlarged resection cap and an integrated snare. The device prototype allows combined resection of all gastrointestinal organ wall layers in one maneuver, up to a size of 3 x 3 cm. The device has been pre-clinically tested to demonstrate feasibility of full-thickness resection in the colon. Two clinical cases have been performed successfully to date.

Effective relief of malignant ascites in patients with advanced ovarian cancer by a trifunctional anti-EpCAM x anti-CD3 antibody: a phase I/II study.

PURPOSE: Malignant ascites in ovarian carcinoma patients is associated with poor prognosis and reduced quality of life. The trifunctional antibody catumaxomab (anti-EpCAM x anti-CD3) enhances the antitumor activity by redirecting T cells and Fcgamma receptor I/III--positive accessory cells to the tumor. This multicenter phase I/II dose-escalating study investigated tolerability and efficacy of i.p. catumaxomab application in ovarian cancer patients with malignant ascites containing epithelial cell adhesion molecule (EpCAM)--positive tumor cells. EXPERIMENTAL DESIGN: Twenty-three women with recurrent ascites due to pretreated refractory ovarian cancer were treated with four to five i.p. infusions of catumaxomab in doses of 5 to 200 microg within 9 to 13 days. RESULTS: The maximum tolerated dose was defined at 10, 20, 50, 200, and 200 microg for the first through fifth doses. Side effects included transient fever (83%), nausea (61%), and vomiting (57%), mostly CTCAE (Common Terminology Criteria for Adverse Events) grade 1 or 2. A total of 39 grade 3 and 2 grade 4 treatment-related adverse events (AE), 9 of them after the highest dose level (200 microg), were observed in 16 patients. Most AEs were reversible without sequelae. Treatment with catumaxomab resulted in significant and sustained reduction of ascites flow rate. A total of 22/23 patients did not require paracentesis between the last infusion and the end of study at day 37. Tumor cell monitoring revealed a reduction of EpCAM-positive malignant cells in ascites by up to 5 log. CONCLUSION: I.p. immunotherapy with catumaxomab prevented the accumulation of ascites and efficiently eliminated tumor cells with an acceptable safety profile. This suggests that catumaxomab is a promising treatment option in ovarian cancer patients with malignant ascites.

Microwave-assisted generation of alkoxyl radicals and their use in additions, beta-fragmentations, and remote functionalizations.

Microwave irradiation (2.45 GHz, 300-500 W) of N-(alkoxy)thiazole-2(3H)-thiones in low-absorbing solvents affords alkoxyl radicals, which were identified by (i) spin adduct formation (EPR-spectroscopy) and (ii) fingerprint-type selectivities in intramolecular additions (stereoselective synthesis of disubstituted tetrahydrofurans), beta-fragmentations (formation of carbonyl compounds), and C,H-activation of aliphatic subunits, by delta-selective hydrogen atom transfer. C-Radicals formed from oxygen-centered intermediates were trapped either by Bu(3)SnH, L-cysteine ethyl ester, the reduced form of glutathione (reductive trapping), or by bromine atom donor BrCCl(3) (heteroatom functionalization) The results suggest that microwave activation is superior to UV/Vis-photolysis and conductive heating for alkoxyl radical generation from N-(alkoxy)thiazolethiones. It offers by far the shortest reaction times along with the option to reduce the amount of trapping reagent significantly.

Human monocyte-derived neohepatocytes: a promising alternative to primary human hepatocytes for autologous cell therapy.

BACKGROUND: There is growing interest in new therapeutic options for the treatment of end-stage liver diseases. In addition to mechanical devices supporting liver function, such as bioreactors, the transplantation of hepatocyte-like cells derived from (adult) stem cells offer great perspectives. We have generated hepatocyte-like (NeoHep) cells from terminally differentiated peripheral blood monocytes and, in this study, have evaluated these cells as a possible tool for autologous cell therapy. METHODS: Peripheral blood monocytes were cultured under conditions that promote hepatocyte-like differentiation and were characterized for hepatocyte marker expression by reverse-transcriptase polymerase chain reaction, immunohistochemistry, and immunoblotting and for specific secretory and metabolic functions with the appropriate biochemical assays. RESULTS: NeoHep cells resembled primary human hepatocytes with respect to morphology, expression of hepatocyte markers (albumin, cytochrome P450 isoenzymes, asialoglycoprotein receptor, coagulation factor VII), various secretory and metabolic functions (albumin secretion, urea production, lactate formation, and lactate dehydrogenase and aspartate transaminase release), and drug detoxification activities (phase I metabolization of ethoxycoumarin into 7OH-coumarin after stimulation with 3-methylcholanthren, induction of CYP3A4 activity, and phase II metabolization through UDP-glucuronidation of 4-methyl-umbelliferone). CONCLUSIONS: These data convincingly show that NeoHep cells display a phenotype and specific in vitro metabolic functions that are quantitatively and qualitatively comparable in part with those of primary human hepatocytes. These cells could thus be clinically applied in an autologous setting for the treatment of end-stage liver diseases or for improving liver function in patients who have undergone critical liver-mass resection.