Liquid crystal beyond displays: feature introduction.

The editors introduce the feature issue on liquid crystal beyond displays.

Macrovascular venous invasion of pancreatic neuroendocrine tumours: impact on surgical outcomes and survival.

BACKGROUND: This study evaluates the impact of macrovascular venous invasion (MVI) on surgical and survival outcomes of pancreatic neuroendocrine tumours (PNETs). METHODS: We retrospectively reviewed data of 125 patients operated for PNETs. Operative, pathological,and survival outcomes were compared between PNETs with and without MVI. RESULTS: Macrovascular venous invasion was detected in 25 of 125 PNETs (20%) presenting as tumour thrombi (n = 12) or venous wall invasion (n = 13). MVI was associated with larger tumours, a higher rate of lymph node involvement, less differentiated tumours, and a higher rate of perineural invasion. Resection of PNETS with MVI more often necessitated combined hepatic, venous and multivisceral resections, had a higher rate of intraoperative blood transfusion (p = 0.04) but similar morbidity (44% vs. 42%) and mortality (0 vs. 1%) as PNETs without MVI. PNETs with MVI had a lower median overall survival rate (60 vs. 149 months; p = 0.03). Multivariate analysis revealed that PNETs of the pancreatic head, synchronous liver metastases and higher tumour grade were prognostic factors for overall survival. CONCLUSIONS: MVI is found in more advanced PNETs. Resection of PNETs with MVI is characterized by increased transfusion rate and reduced overall survival.

Immediate Effect of Simulated High Heels on Pelvic and Spinal Posture in Healthy Young Subjects: A Cross-Sectional Study.

Background Investigations regarding the role of high-heeled shoes in the alteration of the spinopelvic profile attempted to identify a correlation with pain in the lower back. Conclusions from these studies, however, are controversial. In authors knowledge no studies were carried out to investigate the effect of heels on male population, which has been overlooked due to gender-related customs. Research question What is the immediate effect of the height of heels on the sagittal back profile (trunk inclination (TI), pelvic inclination, lordotic lumbar angle (ITL-ILS), kyphotic dorsal angle, lumbar arrow, and cervical arrow) in females and males, not used to wearing high-heeled shoes? Methods One hundred healthy young adult subjects were enrolled. Three were excluded. The remaining 97 subjects (48 female and 49 male) underwent a three-dimensional analysis of the posterior surface of the trunk, using rasterstereography. The spinopelvic profile in the barefoot condition, and with the heel raised by 3 and 7 cm, was recorded. To evaluate the reproducibility of the measure, the neutral evaluation was repeated twice in 23 subjects (13 males, 10 females). Results The change of heel height did not show statistically significant differences for any of the variables used; instead, significant differences were found stratifying the results according to the sex of the subjects tested. Test-retest evaluation in the neutral condition showed no significant differences using the Student's t-test (p > 0.05). Repeatability was excellent and significant for all data used (minimum TI r = 0.85, maximum ITL-ILS r = 0.97). Significance Studying the effect of heels on the spino-pelvic profile also in the male population is crucial for promoting gender-inclusive healthcare, enhancing occupational health practices and developing possible preventive measures. Nevertheless, in the sample of females and males evaluated in this study, the different heights of heel lift did not immediately induce significant changes in pelvis and spine posture. If there is therefore a correlation between low-back pain and the use of heels, it should not reasonably be sought in the immediate change of the spino-pelvic profile caused by raising the heels. However, the variables analyzed differed according to sex.

Endothelium/nitric oxide mechanism mediates vasorelaxation and counteracts vasoconstriction induced by low concentration of flavanols.

PURPOSE: At relatively low concentrations, flavanols induce inconsistent effects on isolated arterial tone, sometimes explained as being due to a structure-activity relationship. The aim of our study was to investigate the effects of two flavanols at different doses on arterial functional state. METHODS: The effects of two catechins, (-)-epigallocatechin-3-gallate (EGCG) and (-)-epicatechin (EP), on rat-isolated aorta tone were investigated on resting tension and on precontracted preparations, both in the presence and in the absence of endothelium. RESULTS: At resting tension, endothelium-intact preparations, EGCG and EP (0.01-10 µM), induced a slight concentration-dependent, non-significant contraction. On endothelium-denuded preparations, both EGCG and EP induced a concentration-dependent contraction (significance at 0.1 and 1 µM concentrations of the two compounds, respectively). In phenylephrine (PE) (1 µM) precontracted, endothelium-intact preparations, EGCG and EP (0.01-10 µM), induced a concentration-dependent vasorelaxation, reaching significance at 1 µM concentration of both agonists. On endothelium-denuded preparations, EGCG and EP did not significantly affect PE (0.3 µM)-induced tone. In endothelium-intact precontracted preparations, Nω nitro-L-arginine (L-NNA), a nitric oxide synthase (NOS) activity inhibitor, abolished the vasorelaxant effect of EGCG and EP (0.01-10 µM). At high concentrations, EGCG and EP (100 µM) elicited a marked relaxation. This was significantly larger in the presence than in the absence of endothelium or in the presence of L-NNA. CONCLUSIONS: Our findings highlight the important role played by an endothelium/NO-mechanism in the regulation of basal tone and in both mediating vasorelaxation and counteracting vasoconstriction induced by low concentrations of flavanols in rat thoracic aorta.

Long term quality of life after laparoscopic antireflux surgery for the elderly.

BACKGROUND: Studies have previously shown laparoscopic antireflux surgery is a safe and effective treatment for GERD even in elderly patients. The aim of the current study was to evaluate patients receiving laparoscopic antireflux surgery before and after 65 years of age and to assess their surgical outcomes and improvements in long term quality of life. METHODS: Patients were given a standardized symptoms questionnaire and the Short-Form 36 Health Survey for quality-of-life evaluation before and after laparoscopic total fundoplication. RESULTS: Forty-nine patients older than 65 years of age were defined as the elderly group (EG) whereas the remaining 262 younger than 65 years of age were defined as the young group (YG). CONCLUSIONS: In conclusion, laparoscopic total fundoplication is a safe and effective surgical treatment for gastroesophageal reflux disease generally warranting low morbidity and mortality rates and a significant improvement of symptoms comparable. An improved long-term quality of life is warranted even in the elderly.

The impact of age and oral calcium and vitamin D supplements on postoperative hypocalcemia after total thyroidectomy. A prospective study.

BACKGROUND: Hypocalcemia caused by transient or definitive hypoparathyroidism is the most frequent complication after total thyroidectomy (TT). We aimed to compare the impact of age and the clinical usefulness of oral calcium and vitamin D supplements on postoperative hypocalcemia after TT, and to determine which risk factors are important for hypocalcemia incidence. METHODS: Two hundred consecutive patients treated by TT were included prospectively in the present study. All patients supplemented oral calcium and vitamin D in the post-operative time. The data concerning symptomatic and laboratoristichypocalcemia were collected. RESULTS: Symptomatic hypocalcemia developed only in 19 patients (9.5%), whereas laboratory hypocalcemia developed in 36 patients (18%). The risk for postoperative hypocalcemia was increate 20-fold for patients older than 50 years. CONCLUSIONS: Age is significantly associated with postoperative hypocalcemia. Implementing oral calcium and vitamin D after total thyroidectomy can reduce the incidence of hypocalcemia related to surgery.

[First report of Echinococcus vogeli in a paca in Misiones province, Argentina]. / Primera identificación de Echinococcus vogeli en una paca en la provincia de Misiones, Argentina.

We report the first finding of Echinococcus vogeli in a paca, Cuniculus paca, in the tropical forest of Misiones, in the north of Argentina. The presence of the bush dog, Speothos venaticus, E. vogelís only natural definitive host, was also reported. The polycystic hydatids, 2 to 3 cm in diameter, were only found in the liver of an adult paca. The size range of the hooks and the relative proportion blade/handle did not show significant differences with respect to the ones reported for E. vogeli. The size of E. granulosus hooks, measured for comparison purposes, was significantly smaller (p E. vogeli in Argentina. The probability of finding neotropical echinococcosis in humans reinforces the need to expand the search for E. vogeli in Argentina. Echinococcosis due to E. vogeli is very aggressive and may cause death in about a third of the human population affected.

Endoscopy management of sleeve gastrectomy stenosis: what we learned from 202 consecutive patients.

BACKGROUND: Gastric sleeve stenosis (GSS) is described in 1%-4% of patients. OBJECTIVE: To evaluate the role of endoscopy in the management of stenosis after laparoscopic sleeve gastrectomy using a standardized approach according to the characteristic of stenosis. SETTING: Retrospective, observational, single-center study on patients referred from several bariatric surgery departments to an endoscopic referral center. METHODS: We enrolled 202 patients. All patients underwent endoscopy in a fluoroscopy setting, and a systematic classification of the type, site, and length of the GSS was performed. According to the characteristics of the stenosis, patients underwent pneumatic dilatation or placement of a self-expandable metal stent or a lumen-apposed metal stent. Failure of endoscopic treatment was considered an indication for redo surgery, whereas patients with partial or complete response were followed up for 2 years. In the event of a recurrence, a different endoscopic approach was used. RESULTS: We found inflammatory strictures in 4.5% of patients, pure narrowing in 11%, and functional stenosis in 84.5%. Stenosis was in the upper tract of the stomach in 53 patients, whereas medium and distal stenosis was detected in 138 and 11 patients, respectively, and short stenosis in 194 patients. A total of 126 patients underwent pneumatic dilatation, 8 self-expandable metal stent placement, 64 lumen-apposed metal stent positioning, and 36 combined therapy. The overall rate of endoscopy success was 69%. CONCLUSION: GSS should be considered to be a chronic disease, and the endoscopic approach seems to be the most successful treatment, with a prolonged positive outcome of 69%. Characteristics of the stenosis should guide the most suitable endoscopic approach.

Impact of total fundoplication on esophageal transit: analysis by combined multichannel intraluminal impedance and manometry.

BACKGROUND: Laparoscopic total fundoplication is considered the most effective surgical option for gastroesophageal reflux (GER) disease. Some authors assume that total fundoplication may expose the patient to delayed transit of the swallowed bolus and increased risk of dysphagia, particularly when peristaltic dysfunction is present. We undertook this study to evaluate by means of combined multichannel intraluminal impedance and esophageal manometry (MII-EM) the impact of fundoplication on esophageal physiology. An objective measurement of the influence of the total wrap on bolus transit may be helpful in refining the optimal antireflux wrap (ie, partial vs. total). METHODS: In this study, 25 consecutive patients who underwent laparoscopic Nissen-Rossetti fundoplication had MII-EM and combined 24-hour pH and multichannel intraluminal impedance (MII-pH) before and after the surgical procedure. All patients completed preoperative and postoperative symptom questionnaires. The following were calculated for liquid and viscous deglutition lower esophageal sphincter pressure and relaxation, distal esophageal amplitude, the number of complete esophageal bolus transits and the mean total bolus transit time. The acid and nonacid GER episodes were calculated by MII-pH with the patient in both upright and recumbent positions. RESULTS: The postoperative MII-EM showed an increased lower esophageal sphincter pressure (P < 0.05), whereas lower esophageal sphincter relaxation and distal esophageal amplitude did not change after surgery (P = NS). Complete esophageal bolus transits and bolus transit time did not change for liquid swallows (P = NS), but was more rapid for viscous after surgery (P < 0.05). Twenty-four hour pH monitoring confirmed the postoperative reduction of both acid and nonacid reflux (P < 0.05). CONCLUSIONS: Laparoscopic Nissen-Rossetti is effective in controlling both acid and nonacid GER without impairment of esophageal function. Appropriate preoperative investigation, meticulous patient selection and correct surgical technique are extremely important in securing good results.

The use of Permacol® biological mesh for complex abdominal wall repair.

BACKGROUND: Complex abdominal wall repair (CAWR) remains challenging, especially in contaminated fields where the use of a synthetic mesh is associated with prohibitively complication rates. Consequently, biological mesh has been proposed as an alternative. The aim of our study was to evaluate the safety and efficacy of using Permacol® in patients who had CAWR. METHODS: We retrospectively reviewed the files of patients who had CAWR using the Permacol® mesh. Analysis included patients' preoperative characteristics, procedural parameters, and early and late post-operative complications including mainly recurrence. A multivariate regression model was performed to determine factors that influence 24-months recurrence rate. RESULTS: Between January 2009 and December 2018, 75 patients. The most common indication was hernia in a contaminated field (48.0%) and abdominal wall defect greater than 10 cm in diameter (36%). Overall, 44% of our patients were Centers for Disease Control (CDC) class II or III and 81.3% fall into category II or III according to the Ventral Hernia Working Group (VHWG) classification. Recurrence rate of our series was 9.3%. Complete fascial closure was achieved in 60 patients (80%). Upon univariate analysis complete fascial closure, posterior component separation, seroma drainage, BMI>30 kg/m2 and age >65 years, VHWD grade >2, DINDO CLAVIEN class >2 affected the recurrence rate at 2 years follow-up. When subcutaneous drains are placed prophylactically, recurrence rates drop from 38.7% (5/14) to 3.3% (2/61 patients) when drains are placed at the time of operation (P=0.02). Only fascial closure affected the 24-months recurrence rate on multivariate analysis (P<0.001). CONCLUSIONS: Permacol® surgical implant use for CAWR is safe with a relatively low rate of hernia recurrence at 2 years. Prophylactic subcutaneous drain placement may reduce the risk of hernia recurrence. The presence of contaminated fields does not appear to influence hernia recurrence when Permacol® is used, in fact, the only factor that affects recurrence rate at 24-months on multivariate analysis is completeness of the fascial closure.

Observation of tunable optical filtering in photosensitive composite structures containing liquid crystals.

We report on the investigation and characterization of an optically tunable filtering effect, observed in a waveguide grating made of alternated strips of photocurable polymer and a mixture of azo-dye-doped liquid crystal. The grating is sandwiched between two borosilicate glasses, one of which includes an ion-exchanged channel waveguide, which confines the optical signal to be filtered. Exposure to a low power visible light beam modifies the azo-dye molecular configuration, thus allowing the filtered wavelength to be tuned over a 6.6 nm range. Simulations of the filtering response are well described with our experimental findings.

Widely tunable electro-optic distributed Bragg reflector in liquid crystal waveguide.

We propose and numerically investigate a versatile and easy-to-realize configuration for a guided-wave voltage-tunable distributed feedback grating based on reorientation in nematic liquid crystal and coplanar comb electrodes. The device has a wide tuning range exceeding 100 nm and covers C and L bands for wavelength division multiplexing.

New aspects of neotropical polycystic (Echinococcus vogeli) and unicystic (Echinococcus oligarthrus) echinococcosis.

Of the four species of the genus Echinococcus (Cestoda) distinguished by biological and morphological characteristics, two species, E. vogeli and E. oligarthrus, occur widely in the Neotropics. Approximately 200 cases of polycystic echinococcosis (PE) have been recorded from 12 countries in South America. Following early proliferation of E. vogeli in the human host, typically in the liver, the metacestode usually spreads in the peritoneal and pleural cavities, and numerous organs may be invaded. The clinical characteristics of PE in 81 patients with sufficient information are reviewed. Type I disease consists of polycysts in the liver and abdominal cavity (37% of the patients had this characteristic); type II is similar to type I but also includes hepatic insufficiency (26%); type III consists of cysts in liver and chest (14%); type IV consists of cysts only in the mesenteries (16%); and type V consists of cysts calcified in liver and lung (4%). The percentage of patients with polycysts in the liver was 81%, and the percentage of patients with polycysts in the chest was 14%. PE is most ready diagnosed by geographic origin of the patient and by means of ultrasound or computerized tomography scanning showing cysts and calcifications. The highest mortality was for patients with type II disease, due to hepatic failure and its complications. There were five patients who died due to surgical accidents, whereas 35 cases had uncomplicated surgery. Twenty-three patients died of PE, making the total mortality 29% (23 of 78 cases). None of the 13 patients treated only with albendazole, the most efficacious treatment, was completely cured. PE represents a severe medical problem in South America. A reevaluation of the characteristics of the metacestode of E. oligarthrus indicated that it is unicystic. Only three human cases are known (two with infection in the orbit and one with infection in the heart). The metacestode of E. oligarthrus, in contrast with that of E. vogeli, consists of a spherical, fluid-filled vesicle that enlarges concentrically and is not known to undergo exogenous proliferation.

Roux-en-Y Gastro-jejunostomy for Complex Leak After the "Nissen" Variant of Sleeve Gastrectomy.

BACKGROUND: Recently, improvised variants of sleeve gastrectomy SG were reported as alternative bariatric options in patients suffering from both morbid obesity and GERD, including mainly additional anterior or posterior fundoplication over a partially sleeved stomach. METHODS: We present the case of a 29-year-old male patient with a body mass index (BMI) of 46.2 kg/m2 underwent laparoscopic SG with concomitant posterior fundoplication: Nissen-SG (N-SG). At postoperative day (POD) 4, he presented with epigastric pain, nausea, and 40 °C fever. The abdomen was tender with signs of peritonitis. Explorative laparotomy displayed a massive gastric leak with generalized peritonitis. Peritoneal lavage was performed. the patient was transferred to our department for the management of persistent SGL. RESULTS: Initial management comprised total parenteral nutrition and wide-spectrum intravenous antibiotics. Three weeks later, the patient underwent laparoscopic exploration. As shown in the video, at least two leaks were individualized, including one, anterior, catheterized by the pigtails, and the other one, posterior, impossible to reach endoscopically (Fig. 1). A residual abscess, located between the left crus, the pancreas, and the upper edge of the spleen, was evacuated. Eventually, Roux-en-Y gastro-jejunostomy was performed CONCLUSION: The adjunction of a posterior fundoplication may have contributed to the multiple and complex occurrence of SGL. Having an ill-vascularized redundant fundus may have increased ischemia of the GE junction. Moreover, it is more difficult to perform endoscopic treatment in a plicated and sleeved stomach as well.

König's Syndrome After Roux-en-Y Gastric Bypass: Candy Cane Twist.

BACKGROUND: A König's syndrome is referred to abdominal pain in relation to meals with constipation alternated with diarrhea, meteorism, and abdominal distension. A postoperative long-term complication after Roux-en-Y gastric bypass could be the appearance of chronic abdominal pain associated with vomiting, dysphagia, and nausea. CASE REPORT: A 43-year-old female patient was submitted for a Roux-en-Y gastric bypass for morbid obesity with an initial body mass index (BMI) of 36 kg/m2 (weight 100 kg, height 168 cm). At the 5-year follow-up, the patient's BMI was 22.3 kg/m2 with a weight loss of 40 kg. In the last month, the patient has undergone a further weight loss of 8 kg (BMI 18.4 kg/m2) with the presence of chronic abdominal pain, dyspepsia, and dysphagia and abdominal distension. Any vasomotor problems (hot flushing, sweating, palpitations, and diarrhea) were described. The computer tomography (CT) with oral contrast shows the presence of a blind afferent Roux limb at the gastrojejunostomy, explaining a possible König's syndrome. RESULTS: The patient was submitted for a diagnostic laparoscopy, which revealed the presence of a twisted candy cane that was identified and resected. The postoperative stages were uneventful and the patient was discharged on the second postoperative day. CONCLUSION: Candy cane syndrome is a rare and challenging complication reported in bariatric patients following Roux-en-Y gastric bypass and is best investigated with a barium swallow or oesophago-gastro-duodenoscopy (OGD). This means that this kind of pathology could be avoided by not leaving such a long blind loop during the primary gastric bypass operation. An explorative laparoscopy could be performed in the event of abdominal pain, nausea, and vomiting at a long-term follow-up after gastric bypass. Even if there are little data regarding the efficacy of surgical treatment, if present, "candy cane" surgical revision seems to be the best treatment for the majority of the patients with long-term symptomatic relief.

Correction to: Weight Regain After Gastric Plication: Reoperative Sleeve Gastrectomy or Roux-en-Y Gastric Bypass?-Analysis of 116 Consecutive Cases.

In the original article the name of author Luigi Prisco was incorrect. It is correct here.

Weight Regain After Gastric Plication: Reoperative Sleeve Gastrectomy or Roux-en-Y Gastric Bypass?-Analysis of 116 Consecutive Cases.

PURPOSE: In France, laparoscopic gastric plication (GP) has rarely been utilized as a weight loss procedure. Although relatively safe and efficient, its long-term results are still controversial. The goal of this study is to assess the indications and outcomes of revisional surgery post-GP. MATERIALS AND METHODS: Between February 2010 and September 2017, patient characteristics undergoing GP were prospectively collected from our database. Failure of conservative treatment or presence of anatomical anomaly explaining weight loss insufficiency was an indication for revisional surgery (RS). RESULTS: A total of 300 patients were included, 41 patients were lost to follow-up (13.7%), 124 patients (41.3%) had total weight loss (TWL) > 30%, and 116 patients (38.7%) underwent RS. Revisional procedures were laparoscopic Roux-en-Y gastric bypass (RYGB) in 72 patients (62.1%) and sleeve gastrectomy (SG) in 44 patients (37.9%). The median interval to RS was 29 months. The mean operative time was 60 min for the SG and 125 min for the RYGB (p < 0.0001). Mortality was nil. Significant morbidity occurred in eight patients (6.9%) including 4 non-abdominal complications, 1 gastric leak, 1 case of hemorrhage, 1 case of hematoma, and 1 intra-abdominal abscess. The mean length of hospital stay (LOS) was 2.9 days (range, 1-11) for the SG group vs 3.2 days (range, 2-8) for the RYGB group (p = 0.608). CONCLUSION: GP is associated with a relatively high rate of weight regain or insufficient weight loss. When compared to SG, RYGB seems to be the safer revisional procedure with fewer surgical complications.

Distributed feedback grating in liquid crystal waveguide: a novel approach.

We design a distributed feedback guided-wave device in liquid crystals, utilizing a simple geometry based on electro-optic molecular reorientation in uniaxial nematics. We numerically test the structure and demonstrate an effective Bragg reflector with voltage-tunable resonance.

Correction to: Massive Gastrointestinal Bleeding Due to Splenic Artery Erosion by a PigTail Drain in a Post Sleeve Gastrectomy Leak: a Case Report.

The name of author Frédérick Moryoussef was incorrect in the original article - it is correct here.

Tunable integrated optical filter made of a glass ion-exchanged waveguide and an electro-optic composite holographic grating.

We report the fabrication and the optical characterization of a hybrid tunable integrated optical filter. It consists of a diffused ion-exchanged channel waveguide on a borosilicate glass substrate with a cover of the same glass to form a gap filled with a holographic grating. The grating morphology, called POLICRYPS (POlymer LIquid CRYstal Polymer Slices), is made of alternating stripes of polymer and liquid crystal acting as overlayer for the underneath waveguide. The filter structure includes aluminum coplanar electrodes to electrically control the grating properties, allowing the tunability of the filter. The electric driving power required to tune the filter obtained was in the range of submilliwatts due to the efficient liquid crystal electro-optic effect.