A novel glycoside hydrolase 43-like enzyme from Clostridium boliviensis is an endo-xylanase and a candidate for xylooligosaccharide production from different xylan substrates.

An uncharacterized gene encoding a glycoside hydrolase family 43-like enzyme from Clostridium boliviensis strain E-1 was identified from genomic sequence data, and the encoded enzyme, CbE1Xyn43-l, was produced in Escherichia coli. CbE1Xyn43-l (52.9 kDa) is a two-domain endo-ß-xylanase consisting of a C-terminal CBM6 and a GH43-like catalytic domain. The positions of the catalytic dyad conserved in GH43, the catalytic base (Asp74), and proton donor (Glu240) were identified in alignments including GH43-enzymes of known 3D-structure from different subfamilies. CbE1Xyn43-l is active at pH 7.0-9.0, with optimum temperature at 65°C, and a more than 7 days' half-life in irreversible deactivation studies at this temperature. The enzyme hydrolyzed birchwood xylan, quinoa stalks glucuronoarabinoxylan, and wheat arabinoxylan with xylotriose and xylotetraose as major hydrolysis products. CbE1Xyn43-l also released xylobiose from pNPX2 with low turnover (kcat of 0.044 s-1) but was inactive on pNPX, showing that a degree of polymerization of three (DP3) was the smallest hydrolyzable substrate. Divalent ions affected the specific activity on xylan substrates, which dependent on the ion could be increased or decreased. In conclusion, CbE1Xyn43-l from C. boliviensis strain E-1 is the first characterized member of a large group of homologous hypothetical proteins annotated as GH43-like and is a thermostable endo-xylanase, producing xylooligosaccharides of high DP (xylotriose and xylotetraose) producer. IMPORTANCE: The genome of Clostridium boliviensis strain E-1 encodes a number of hypothetical enzymes, annotated as glycoside hydrolase-like but not classified in the Carbohydrate Active Enzyme Database (CAZy). A novel thermostable GH43-like enzyme is here characterized as an endo-ß-xylanase of interest in the production of prebiotic xylooligosaccharides (XOs) from different xylan sources. CbE1Xyn43-l is a two-domain enzyme composed of a catalytic GH43-l domain and a CBM6 domain, producing xylotriose as main XO product. The enzyme has homologs in many related Clostridium strains which may indicate a similar function and be a previously unknown type of endo-xylanase in this evolutionary lineage of microorganisms.

Heated and humidified insufflation during laparoscopic gastric bypass surgery: effect on temperature, postoperative pain, and recovery outcomes.

BACKGROUND: Controversy exists regarding the efficacy of heated and humidified intraperitoneal gases in maintaining core body temperature. We performed a sham-controlled study to test the hypothesis that active warming and humidification of the insufflation gas reduces intraoperative heat loss and improves recovery outcomes. PATIENTS AND METHODS: Fifty morbidly obese patients undergoing laparoscopic Roux-en-Y gastric bypass procedures using a standardized anesthetic technique were randomly assigned to either a control (sham) group receiving room temperature insufflation gases with an inactive Insuflow (Lexion Medical, St. Paul, MN) device, or an active (Insuflow) group receiving warmed and humidified intraperitoneal gases. Esophageal and/or tympanic membrane temperature was measured perioperatively. Postoperative pain was assessed at 15 minute intervals using an 11-point verbal rating scale, with 0 = none to 10 = maximal. In addition, postoperative opioid requirements, incidence of nausea and vomiting, as well as the quality of recovery, were recorded. RESULTS: Use of the active Insuflow device was associated with significantly higher mean +/- standard deviation (SD) intraoperative core body temperatures (35.5 +/- 0.5 vs. 35.0 +/- 0.4 degrees C). Postoperative shivering (0 vs. 19%) and the requirement for morphine in the postanesthesia care unit (5 +/- 4 vs. 10 +/- 5 mg) were both significantly lower in the Insuflow vs. control groups. Patients in the Insuflow group also reported a higher quality of recovery 48 hours after surgery (15 vs. 13, P < 0.05). CONCLUSION: The Insuflow device modestly reduced shivering and heat loss, as well as the need for opioid analgesics in the early postoperative period. However, it failed to improve laparoscopic visualization due to fogging, and provided improvement in the quality of recovery only on postoperative day 2.

Ecografía intraoperatoria del páncreas / Intraoperative ultrasound in pancreatic pathology

Antecedentes: La ecografía intraoperatoria (EIO) es una herramienta fundamental que asiste al cirujano en la toma de decisiones con respecto a la resecabilidad de los tumores periampulares y para la detección y guía terapéutica de los tumores neuroendocrinos del páncreas. Objetivo: Evaluar la utilidad de la ecografía intraoperatoria en patología pancreática. Lugar de aplicación: Hospital Privado de Comunidad. Diseño: Serie de casos. Retrospectivo. Material y método: En el período junio 1996 a diciembre 1999, se realizaron 64 ecografías intraoperatorias en 64 pacientes operados de páncreas. La edad promedio de la población fue de 58 años. Las patologías tratadas fueron 46 carcinomas periampulares (5 de ellos con diagnóstico preoperatorio de irresecabilidad por tomografías computadas), 12 tumores quísticos, 4 pancreatitis crónicas y 2 tumores neuroendocrinos. Resultados: EIO modificó la estrategia intraoperatoria en 44 pacientes (67,2 por ciento). En carcinomas periampulares, la EIO fue útil para comprobar la invasión portal en 37 pacientes (80,4 por ciento) 8 de ellos también presentaron metástasis hepáticas (17,4 por ciento). En tumores quísticos, en 6 pacientes se encontró criterios ecográficos de malignidad (50 por ciento). En un paciente con insulinoma pancreático la EIO demostró enfermedad multicéntrica siendo necesario realizar pancretectomía total. En pancreatitis crónica la EIO fue útil para realizar punción biopsia de ganglios paraaórticos y también para elegir el lugar apropiado para realizar quisto-gastro anastomosis. Conclusiones: EIO en patología pancreática cambió la estrategia quirúrgica en 67,2 por ciento de los pacientes. En carcinoma periampular la visión de la invasión portal fue útil para no realizar una exploración quirúrgica agresiva y para evitar maniobras riesgosas. En tumores quísticos fue útil para diferenciar lesiones benignas de lesiones maliganas. Pequeños tumores neuroendocrinos fueron localizados con este método. En pseudoquistes pancreáticos el espesor de la pared y el lugar correcto para la anastomosis pudieron ser evaluados

Ecografía intraoperatoria del páncreas / Intraoperative ultrasound in pancreatic pathology

Antecedentes: La ecografía intraoperatoria (EIO) es una herramienta fundamental que asiste al cirujano en la toma de decisiones con respecto a la resecabilidad de los tumores periampulares y para la detección y guía terapéutica de los tumores neuroendocrinos del páncreas. Objetivo: Evaluar la utilidad de la ecografía intraoperatoria en patología pancreática. Lugar de aplicación: Hospital Privado de Comunidad. Diseño: Serie de casos. Retrospectivo. Material y método: En el período junio 1996 a diciembre 1999, se realizaron 64 ecografías intraoperatorias en 64 pacientes operados de páncreas. La edad promedio de la población fue de 58 años. Las patologías tratadas fueron 46 carcinomas periampulares (5 de ellos con diagnóstico preoperatorio de irresecabilidad por tomografías computadas), 12 tumores quísticos, 4 pancreatitis crónicas y 2 tumores neuroendocrinos. Resultados: EIO modificó la estrategia intraoperatoria en 44 pacientes (67,2 por ciento). En carcinomas periampulares, la EIO fue útil para comprobar la invasión portal en 37 pacientes (80,4 por ciento) 8 de ellos también presentaron metástasis hepáticas (17,4 por ciento). En tumores quísticos, en 6 pacientes se encontró criterios ecográficos de malignidad (50 por ciento). En un paciente con insulinoma pancreático la EIO demostró enfermedad multicéntrica siendo necesario realizar pancretectomía total. En pancreatitis crónica la EIO fue útil para realizar punción biopsia de ganglios paraaórticos y también para elegir el lugar apropiado para realizar quisto-gastro anastomosis. Conclusiones: EIO en patología pancreática cambió la estrategia quirúrgica en 67,2 por ciento de los pacientes. En carcinoma periampular la visión de la invasión portal fue útil para no realizar una exploración quirúrgica agresiva y para evitar maniobras riesgosas. En tumores quísticos fue útil para diferenciar lesiones benignas de lesiones maliganas. Pequeños tumores neuroendocrinos fueron localizados con este método. En pseudoquistes pancreáticos el espesor de la pared y el lugar correcto para la anastomosis pudieron ser evaluados (AU)

A method to attenuate pneumoperitoneum-induced reductions in splanchnic blood flow.

OBJECTIVE: To determine if increasing nitric oxide bioactivity by inclusion of ethyl nitrite (ENO) in the insufflation admixture would attenuate pneumoperitoneum-induced decreases in splanchnic perfusion. SUMMARY BACKGROUND DATA: Organ blood flow is reduced during pneumoperitoneum and can contribute to laparoscopy-associated morbidity and mortality. Previous attempts to control such decreases in flow have been ineffective. METHODS: Laser-Doppler flow probes were placed on the liver and right kidney of anesthetized pigs. After a baseline recording period, animals were insufflated to a final intraperitoneal pressure of 15 mm Hg. Group one received CO2 (standard practice), whereas group 2 received CO2 plus 100 ppm ENO. Insufflation was maintained for 60 minutes and then the abdomen was manually deflated; monitoring was continued for another 60 minutes. RESULTS: CO2 insufflation (n = 5) cut liver blood flow in half; liver flow remained at this level throughout the postinsufflation period. Inclusion of 100 ppm ENO (n = 6) attenuated both the acute and prolonged blood flow decreases. Statistical modeling of the data showed that, on average, liver blood flow was 14.3 U/min higher in the ENO pigs compared with the CO2 group (P = 0.0454). In contrast, neither treatment significantly altered kidney blood flow (P = 0.6215). CONCLUSION: The data indicate that ENO can effectively attenuate pneumoperitoneum-induced blood flow decreases within the peritoneal cavity. The result suggests a novel therapeutic method of regulating hemodynamic changes during laparoscopic procedures.

Laparoscopic choledochojejunostomy via PTFE-covered stent successfully achieves internal drainage of common bile duct obstruction.

The purpose of this study was to develop a method of laparoscopic biliary bypass utilizing a PTFE-covered biliary stent. An animal model of common bile duct obstruction was developed. Three days before the planned choledochojejunostomy, the common duct in 10 female pigs was ligated using mini-laparoscopy instrumentation (2 mm) to create an obstruction model. A laparoscopic choledochojejunostomy was then performed using intracorporal suturing (n=5) or stented (n=5) techniques. In the sutured group, a side-to-side two-layer anastomosis was performed. In the stented group, a Seldinger technique was used to deliver the stent into the abdomen through the small bowel and into the anterior wall of the common bile duct for deployment across both the duct and bowel to create an anastomosis (under fluoroscopic guidance). After the surgery, the animals were followed for 7 days, and then sacrificed to examine the anastomosis grossly and histologically. Statistical analysis was used to compare the two groups. Although the difference was not statistically significant, the mean anastomosis time in minutes was shorter for the stented group (37.8; range 15-74 minutes) than in the sutured group (52.8; range 28-70 minutes). All animals survived for 7 days after the procedure with no detectable biliary leaks or biliary obstruction at autopsy. These gross findings were confirmed by pathologic examination of the anastomoses. Laparoscopic choledochojejunostomy using a PTFE-covered metallic biliary stent can be performed to relieve common bile duct obstruction. In addition, the stent method was as safe and effective as sutured laparoscopic choledochojejunostomy.

Robotically assisted laparoscopic Roux-en-Y hepaticojejunostomy.

INTRODUCTION: This study evaluates the feasibility and safety of using robotically assisted laparoscopy to perform a Roux-en-Y hepaticojejunostomy. This new method was compared with the open and standard laparoscopic approaches. METHODS: Eighteen pigs underwent a needlescopic common bile duct ligation to create a jaundice model. Three to 5 days later, transabdominal ultrasound was performed, and the common bile duct diameter was documented. For the Roux-en-Y hepaticojejunostomy, the pigs were randomly assigned to the open group (n=6), standard laparoscopy group (n=6), or robotically assisted laparoscopy group (Zeus) (n=6). One surgeon performed all 3 approaches with 1 assistant. Operative times, techniques, and complication rates were documented. RESULTS: The open approach was faster in all instances. At the hepaticojejunostomy, no difference was noted between the groups with the total number of stitches used. The robot required fewer stitches and less time in the posterior wall of the hepaticojejunostomy (P=-0.0083 and P=0.02049, respectively). The hepaticojejunostomy time was similar for the laparoscopy and robotically assisted groups. CONCLUSION: Robotically assisted laparoscopic Roux-en-Y hepaticojejunostomy is a feasible procedure. When compared with standard laparoscopy, operating time is similar.

Is routine cholecystectomy required during laparoscopic gastric bypass?

BACKGROUND: Routine cholecystectomy is often performed at the time of gastric bypass for morbid obesity. The aim of our study was to determine the incidence of gallstone formation requiring cholecystectomy following a laparoscopic Roux-en-Y gastric bypass (LRYGBP). METHODS: 289 LRYGBP were performed between November 1999 and May 2002. 60 patients (21%) who had prior cholecystectomy were excluded. If gallstones were identified by intra-operative ultrasound (IOUS), simultaneous cholecystectomy was performed. Patients without gallstones were prescribed ursodiol for 6 months and scheduled for follow-up with transabdominal ultrasound. RESULTS: During LRYGBP, gallstones were detected in 40 patients using IOUS (14%) and simultaneous cholecystectomy was performed. Of 189 patients with no stones identified by IOUS, 151 patients (80%) had a postoperative ultrasound after 6 months. 39 patients developed gallstones (22%) and 12 developed sludge (8%), as demonstrated by ultrasound at the time of follow-up. 11 patients had gallstone-related symptoms and subsequently underwent cholecystectomy (7%). 106 patients (70%) were gallstone-free at the time of ultrasound follow-up. Ursodiol compliance was found to be significantly lower for patients developing stones than for gallstone-free patients (38.9% vs 58.3%, z =-2.00, P = 0.045). CONCLUSIONS: There is a low incidence of symptomatic gallstones requiring cholecystectomy after LRYGBP. Prophylactic ursodiol is protective. Routine IOUS and selective cholecystectomy with close patient follow-up is a rational approach in the era of laparoscopy.

Is routine cholecystectomy required during laparoscopic gastric bypass?

BACKGROUND: Routine cholecystectomy is often performed at the time of gastric bypass for morbid obesity. The aim of this study was to determine the incidence of gallstone formation requiring cholecystectomy following a laparoscopic Roux-en-Y gastric bypass (LRYGBP). METHODS: 289 LRYGBP were performed between November 1999 and May 2002. 60 patients (21%) who had prior cholecystectomy were excluded. If gallstones were identified by intra-operative ultrasound (IOUS), simultaneous cholecystectomy was performed. Patients without gallstones were prescribed ursodiol for 6 months and scheduled for follow-up with transabdominal ultrasound. RESULTS: During LRYGBP, gallstones were detected in 40 patients using IOUS (14%) and simultaneous cholecystectomy was performed. Of 189 patients with no stones identified by IOUS, 151 patients (80%) had a postoperative ultrasound after 6 months. 33 patients developed gallstones (22%) and 12 developed sludge (8%) as demonstrated by ultrasound at the time of follow-up. 11 patients had gallstone-related symptoms and subsequently underwent cholecystectomy (7%). 106 patients (70%) were gallstone-free at the time of ultrasound follow-up. Ursodiol compliance was found to be significantly lower for patients who developed stones than for gallstone-free patients (38.9% vs 58.3%, z =-2.00, P = 0.045). CONCLUSIONS: There is a low incidence of symptomatic gallstones requiring cholecystectomy after LRYGBP. Prophylactic ursodiol is protective. Routine IOUS and selective cholecystectomy with close patient follow-up is a rational approach in the era of laparoscopy.

Basic ultrasound curriculum for medical students: validation of content and phantom.

Effective use of ultrasound requires an understanding of the physics, combined with the ability to interpret the sonographic images. The aim of our study was to evaluate the impact of a basic ultrasound curriculum using a phantom to train medical students. Twenty-eight first- to fourth-year medical students were randomized to two groups: a control group that received no formal training and a trained group that received basic ultrasound training. Both groups took an initial multiple-choice written test and an ultrasound hands-on test using an agarose-based tissue mimic containing various objects. The curriculum for the trained group consisted of reading the principles of ultrasound and a hands-on session over the phantom. After training, both groups underwent a second multiple-choice exam and ultrasound practical test. The initial and the post-training test results were analyzed using a two-tailed Student's t-test. Baseline written and practical test scores were similar for both groups. After training, written test scores improved (82% trained vs. 66% control, P < 0.001). Hands-on ultrasound task performance also improved with training (96% trained vs. 60% control, P <0.001). The trained group took a shorter time to obtain a clear image and found on average one more object per scan. Parameters such as time to obtain a useful image and number of objects recognized also improved with training. Basic sonographic physics, imaging, and interpretation can be effectively taught to medical students during a short training session.

Laparoscopic totally extraperitoneal versus Lichtenstein herniorrhaphy: cost comparison at teaching hospitals.

Laparoscopic hernia repair is safe and effective and may result in less postoperative pain and faster recuperation compared with traditional open hernia repairs. Controversy exists as to the increased cost associated with laparoscopic repairs. The purpose of this study was to quantify and compare the cost of the totally extraperitoneal (TEP) laparoscopic repair and the tension-free Lichtenstein repair at teaching hospitals. The records of consecutive TEP (n = 28) and Lichtenstein (n = 28) repairs performed at Parkland Memorial Hospital and Zale-Lipshy University Hospital were reviewed. A detailed cost analysis was performed. Total patient charge (5,509 US dollars vs. 3,999 US dollars) and total cost (2,861 US dollars vs. 2,009 US dollars) were higher for TEP versus Lichtenstein repairs, respectively (P < 0.05). Operative time and complications were similar for both groups. Return to full activity (15 vs. 34 days) was faster for TEP versus Lichtenstein repairs, respectively (P < 0.05). Of 9 patients in the TEP group who had previously undergone an open hernia repair, 8 (89%) preferred the laparoscopic approach. The laparoscopic TEP repair costs 852 US dollars more than the Lichtenstein repair. The TEP repair results in faster recuperation. Patient preference and faster recuperation may offset the increased cost associated with laparoscopic hernia repair.

Laparoscopic Heller myotomy with bolstering partial posterior fundoplication for achalasia.

BACKGROUND: The ideal antireflux procedure following laparoscopic Heller myotomy for achalasia is controversial. We present a novel laparoscopic technique of partial posterior fundoplication to bolster the myotomy. METHODS: Between August 1998 and March 2002, eight patients (five females and three males; median age, 40 years) underwent a laparoscopic Heller myotomy with bolstering partial posterior fundoplication. Results of barium swallow and manometry studies were consistent with achalasia. Failed medical treatments included balloon dilation, botulinum injection, and calcium channel blockers. RESULTS: The preoperative weight loss was 33 lb (range, 10-50) with a mean duration of symptoms of 29 months (range, 12-72). Seventy-one percent of the patients had reflux. Myotomy was confirmed with endoscopic guidance. Partial posterior fundoplication was performed with the edges of the myotomy on the right and left sides sutured to the stomach, which covered the myotomy. No conversion was required. In one patient, a perforation was recognized, repaired, and bolstered. The mean operative blood loss was 72 mL (range, 30-150). The mean operative time was 4 hours. Patients resumed solids at 2.5 days (range, 2-5). Postoperative complications included subcutaneous emphysema (n = 1), pneumothorax (n = 1), and umbilical port hernia (n = 1). None of the patients had reflux symptoms at 3 to 18 months of follow-up. CONCLUSION: Laparoscopic Heller myotomy with partial posterior fundoplication is technically feasible and effectively prevents reflux symptoms. Bolstering the myotomy may help heal small esophageal perforations.