Enhanced light-matter interaction in an atomically thin semiconductor coupled with dielectric nano-antennas.

Unique structural and optical properties of atomically thin two-dimensional semiconducting transition metal dichalcogenides enable in principle their efficient coupling to photonic cavities having the optical mode volume close to or below the diffraction limit. Recently, it has become possible to make all-dielectric nano-cavities with reduced mode volumes and negligible non-radiative losses. Here, we realise low-loss high-refractive-index dielectric gallium phosphide (GaP) nano-antennas with small mode volumes coupled to atomic mono- and bilayers of WSe[Formula: see text]. We observe a photoluminescence enhancement exceeding 10[Formula: see text] compared with WSe[Formula: see text] placed on planar GaP, and trace its origin to a combination of enhancement of the spontaneous emission rate, favourable modification of the photoluminescence directionality and enhanced optical excitation efficiency. A further effect of the coupling is observed in the photoluminescence polarisation dependence and in the Raman scattering signal enhancement exceeding 10[Formula: see text]. Our findings reveal dielectric nano-antennas as a promising platform for engineering light-matter coupling in two-dimensional semiconductors.

Safety and Efficacy of a New Swallowable Intragastric Balloon Not Needing Endoscopy: Early Italian Experience.

PURPOSE: The aim of this study was to evaluate the safety and efficacy of a new intragastric balloon (Elipse™ Balloon, Allurion Technologies, Natick, MA USA) not needing endoscopy. MATERIALS AND METHODS: The balloon was swallowed under fluoroscopy in 38 consecutive patients (F/M 28/10, mean age 46.4 ± 10.6 years, mean weight 109.7 ± 21.9 kg, and mean body mass index (BMI) 38.6 ± 6.7 kg/m2). After 4 months, the balloon spontaneously emptied and it was excreted through the digestive tract without upper endoscopy. RESULTS: There were no complications during balloon passage. After 16 weeks, the mean weight loss was 12.7 kg, mean percent excess weight loss was 26%, and mean BMI reduction was 4.2 kg/m2. Total body weight loss was 11.6%. There was a significant reduction in major co-morbidities related to metabolic syndrome: blood pressure (p < 0.02), waist circumference (p < 0.002), triglycerides (p < 0.0001), blood glucose (p < 0.001), and HOMA-IR index (p < 0.001). At the end of the treatment, 37 balloons were naturally excreted in the stool, and one balloon was endoscopically removed. CONCLUSIONS: The results of this study on 38 consecutive patients demonstrate that the Elipse™ Balloon is safe, effective, and very well accepted by patients.

Long-term results of hiatal hernia mesh repair and antireflux laparoscopic surgery.

BACKGROUND: Laparoscopic antireflux surgery (LARS) represents the gold standard in the treatment of gastroesophageal reflux disease with or without hiatal hernia. It offers excellent long-term results and high patient satisfaction. Nevertheless, several studies have reported a high rate of intrathoracic wrap migration or paraesophageal hernia recurrence. To reduce the incidence of this complication, the use of prosthetic meshes has been advocated. This study retrospectively evaluated the long-term results of LARS with or without the use of a mesh in a series of patients treated from 1992 to 2007. METHODS: From November 1992 to May 2007, 297 patients underwent laparoscopic antireflux surgery in the authors' department. Crural closure was performed by means of two or three interrupted nonabsorbable sutures for 93 patients (group A), by tailored 3 x 4-cm polypropylene mesh placement for 113 patients (group B), and by nonabsorbable suture plus superimposed tailored mesh for 91 patients (group C). RESULTS: The mean follow-up period for the entire group was 95.1 +/- 38.7 months, specifically 95.2 +/- 49 months for group A, 117.6 +/- 18 months for group B, and 69.3 +/-.17.6 months for group C. Intrathoracic Nissen wrap migration or hiatal hernia recurrence occurred for nine patients (9.6%) in group A, two patients (1.8%) in group B, and only one patient (1.1%) in group C. Esophageal erosion occurred in only one case (0.49%). Functional results and the long-term quality-of-life evaluation after surgery showed a significant and durable improvement with no significant differences related to the type of hiatoplasty. CONCLUSION: Over a long-term follow-up period, the use of a prosthetic polypropylene mesh in the crura for hiatal hernia proved to be effective in reducing the rate of postoperative intrathoracic wrap migration or hernia recurrence, with a very low incidence of mesh-related complications.

[Management of uncomplicated arterial hypertension in pregnancy]. / Management clinico-terapeutico dell'ipertensione arteriosa non complicatanella donna in gravidanza.

In the management of uncomplicated arterial hypertension in pregnancy, blood pressure (BP) values of pregnant women should be treated in order to reduce risks of both maternal and fetal complications. To reduce these risks, it is necessary to monitor BP, some hematochemical parameters and albuminuria, to try to prevent more serious clinical complications. Moreover, repeated measurements of BP, as well as frequent ambulatory blood pressure monitoring (ABPM) over 24 h are necessary. In the treatment of hypertension in pregnancy, if there are no high risks, it is possible to try a non pharmacological antihypertensive therapy consisting of a suitable diet, reduction of weight, abolition of some lifestyles (smoking, excessive alcohol consumption and heavy physical exercises). If these measures are not sufficient or the risk is high, a pharmacological therapy with neither toxic nor teratogenic drugs for the fetus will be administered in order to normalize BP without reducing perfusion of the uterus/placenta. Only in case of severe hypertension, a more aggressive pharmacological treatment should be carried out and, if necessary, hospitalization. The drugs suggested in these cases are those which have already been recognised as presenting low side effects. Antihypertensive drugs used in pregnancy can be classified as: suitable (methyldopa, clonidine, long acting calcioantagonists); cautiously used (alpha-blockers, beta-betablockers); contraindicated (ACE-inhibitors, sartans, short acting calcioantagonists). Hyper-tensive crises should be treated with an injection therapy (clonidine, labetalol), with hospital admission if necessary, or if preeclampsia or eclampsia may occur.

BioEnterics Intragastric Balloon (BIB): a short-term, double-blind, randomised, controlled, crossover study on weight reduction in morbidly obese patients.

BACKGROUND: The BioEnterics Intragastric Balloon (BIB) System in association with restricted diet has been used for the short-term treatment of morbid obesity. Aim of this study was to evaluate the real, short term, efficacy of the BIB for weight reduction in morbidly obese patients by using a prospective, double-blind, randomised, sham-controlled, crossover study. METHODS: Patients were recruited from January 2003 to December 2003. After selection, they were randomly allocated into two groups: BIB followed by sham procedure after 3 months (Group A), and sham procedure followed by BIB after 3 months (Group B). All endoscopic procedures were performed under unconscious intravenous sedation. The BioEnterics Intragastric Balloon (Inamed Health; Santa Barbara, CA, USA) was filled by using saline (500 ml) and methylene blue (10 ml). Patients were discharged with omeprazole therapy and diet (1000 kcal). Patients were followed up weekly by a physician blinded to randomisation. In both groups mortality, complications, BMI, BMI reduction and %EWL were considered. Data were expressed as mean +/- s.d., except as otherwise indicated. Statistical analysis was performed by means of Student's t-test, Fisher's exact test or chi (2) with Yates correction; P < 0.05 was considered significant. RESULTS: A total of 32 patients were selected and entered the study (8M/24F; mean age: 36.2 +/- 5.6 years, range 25-50 years; mean BMI 43.7+/-1.5 kg/m(2), range 40-45 kg/m(2); mean %EW: 43.1 +/- 13.1, range: 35-65). All patients completed the study. Mortality was absent. Complications related to endoscopy, balloon placement and removal were absent. Mean time of BIB positioning was 15 +/- 2 min, range 10-20 min. After the first 3 months of the study, in Group A patients the mean BMI significantly (P < 0.001) lowered from 43.5 +/- 1.1 to 38.0 +/- 2.6 kg/m(2), while in Group B patients the decrease was not significant (from 43.6 +/- 1.8 to 43.1 +/- 2.8 kg/m(2)). The mean %EWL was significantly higher in Group A than in Group B (34.0 +/- 4.8 vs 2.1 +/- 1%; P < 0.001). After crossover, at the end of the following 3 months, the BMI lowered from 38.0 +/- 2.6 to 37.1 +/- 3.4 kg/m(2) and from 43.1 +/- 2.8 to 38.8 +/- 3.1 kg/m(2) in Groups A and B, respectively. CONCLUSIONS: The results of this study show that treatment of obese patients with BioEnterics Intragastric Balloon is a safe and effective procedure. In association with appropriate diet it is significantly effective in weight reduction when compared to sham procedure plus diet. The BIB procedure can play a role in weight reduction in morbidly obese patients or in the preoperative treatment of bariatric patients.

BioEnterics Intragastric Balloon: The Italian Experience with 2,515 Patients.

BACKGROUND: The temporary use of the BioEnterics Intragastric Balloon (BIB) in morbidly obesity is increasing worldwide. The aim of this study is the evaluation of the efficacy of this device in a large population, in terms of weight loss and its influence on co-morbidities. METHODS: Data were retrospectively recruited from the data-base of the Italian Collaborative Study Group for Lap-Band and BIB (GILB). After diagnostic endoscopy, the BIB was positioned and was filled with saline (500-700 ml) and methylene blue (10 ml). Patients were discharged with diet counselling ( approximately 1000 Kcal) and medical therapy. The BIB was removed after 6 months. Positioning and removal were performed under conscious or unconscious sedation. Mortality, complications, BMI, %EWL, BMI loss and co-morbidities were evaluated. RESULTS: From May 2000 to September 2004, 2,515 patients underwent BIB (722M/1,793F; mean age 38.9+/-14.7, range 12-71; mean BMI 44.4+/-7.8 kg/m(2) ; range 28.0-79.1; and mean excess weight 59.5+/-29.8 kg, range 16-210). BIB positioning was uncomplicated in all but two cases (0.08%) with acute gastric dilation treated conservatively. Overall complication rate was 70/2,515 (2.8%). Gastric perforation occurred in 5 patients (0.19%), 4 of whom had undergone previous gastric surgery: 2 died and 2 were successfully treated by laparoscopic repair after balloon removal. 19 gastric obstructions (0.76%) presented in the first week after positioning and were successfully treated by balloon removal. Balloon rupture (n=9; 0.36%) was not prevalent within any particular period of BIB treatment, and was also treated by BIB removal. Esophagitis (n=32; 1.27%) and gastric ulcer (n=5; 0.2%) presented in patients without a history of peptic disease and were treated conservatively by drugs. Preoperative co-morbidities were diagnosed in 1,394/2,471 patients (56.4%); these resolved in 617/1,394 (44.3%), improved (less pharmacological dosage or shift to other therapies) in 625/1,394 (44.8%), and were unchanged in 152/1,394 (10.9%). After 6 months, mean BMI was 35.4+/-11.8 kg/m(2) (range 24-73) and %EWL was 33.9+/-18.7 (range 0-87). BMI loss was 4.9+/-12.7 kg/m(2) (range 0-25). CONCLUSIONS: BIB is an effective procedure with satisfactory weight loss and improvement in co-morbidities after 6 months. Previous gastric surgery is a contraindication to BIB placement.

Laparoscopic adjustable silicone gastric banding: prospective evaluation of intragastric migration of the lap-band.

Intragastric prosthesis (Lap-Band, BioEnterics Co., Carpinteria, CA, U.S.A.) migration is one of the major long-term complications of laparoscopic adjustable silicone gastric banding. The causes, clinical signs, timing, and overall incidence of band entrapment have not been prospectively investigated in a large series. The purpose of this study was to assess prospectively the incidence of Lap-Band intragastric migration and to establish the safety and effectiveness of minimally invasive band removal. Between January 1996 and June 2000, 148 consecutive patients enrolled in a multidisciplinary bariatric program underwent laparoscopic adjustable silicone gastric banding. In the follow-up treatment, gastrointestinal endoscopy was performed routinely. One hundred twenty-three patients with a minimum follow-up period of 12 months were entered into the study group. Eleven (9.2%) patients had long-term major complications. Intragastric band migration was observed in nine (7.5%) patients. The diagnosis was established by routine endoscopy between 10 and 41 months after surgery. Five erosions occurred in the first 30 cases (learning curve period). In six patients, the band was removed by an intragastric endoscopic-assisted approach avoiding laparotomy. The remaining three patients are under endoscopic surveillance. The results of this study show that routine upper gastrointestinal endoscopy can discover asymptomatic band migrations early. Band erosion did not require emergency treatment and can be removed safely by a minimally invasive approach.

360 degrees laparoscopic fundoplication with tension-free hiatoplasty in the treatment of symptomatic gastroesophageal reflux disease.

BACKGROUND: Since laparoscopic Nissen fundoplication was first described by Cuschieri in 1989 and later by Dallemagne in 1991, this procedure has been widely employed for the treatment of symptomatic gastroesophageal reflux disease (GERD) and/or hiatal hernia. However, a relatively high incidence (7-11%) of intrathoracic Nissen valve migration/paraesophageal hernia following laparoscopic fundoplication has recently been reported. METHODS: Between November 1992 and August 1995, 65 consecutive patients with severe GERD and/or hiatal hernia underwent laparoscopic 360 degrees fundoplication. In nine of these 65 (13.8%) patients, an intrathoracic Nissen valve migration had occurred within 4 months. Six of these patients were symptomatic and were again submitted to the laparoscopic intervention. Videotapes of both the first and second operation were reviewed. In all cases, it was apparent that, at the first operation, closure by stitches of the hiatus was under tension, and at the second operation, the muscle fibers of the right crus were disrupted, probably due to the tension between the suture margins during the inspiratory movements of the diaphragm. These findings prompted us to perform an effective tension-free closure of the hiatus. A polypropylene mesh (3 x 4 cm) was placed on the hiatus behind the esophagus and fixed with eight metallic agraphes (2 + 2 on the superior edge and 2 + 2 on the lateral sides of the right and left cruses). RESULTS: Between August 1995 and February 1998, the technique, complete with 360 degrees fundoplication, was used for 67 patients with GERD. At mean follow-up of 22.5 months (range, 1-30), there was no evidence of postoperative paraesophageal hernia or complications related to the use of the mesh. CONCLUSIONS: This tension-free hiatoplasty seems to be an effective solution to prevent postoperative paraesophageal hernia in patients undergoing antireflux laparoscopic surgery. However, longer follow-up is still needed.

Plasma lipoproteins affect rate of cholesterol absorbed from bile by gallbladder: preliminary data.

BACKGROUND: The excessive accumulation of cholesterol absorbed from bile by the gallbladder impairs its contractility and favours gallstone formation. The total low plasma and high density lipoprotein cholesterol concentrations are associated with gallstone disease. AIMS: To investigate the effect of plasma lipoproteins on gallbladder cholesterol and phosphatidylcholine absorption from bile and to establish whether cholesterol absorption is Brefeldin A-sensitive. METHODS: Gallbladder mucosa lipid absorption rates were measured using: 1) in vitro isolated intra-arterially perfused pig gallbladder model with and without plasma lipoproteins perfusing the vascular tree; 2) human gallbladder fragments mounted in Ussing chambers with plasma lipoproteins at different concentrations in the serosal side; 3) pig gallbladder fragments mounted in Ussing chambers in the presence and absence of Brefeldin A. RESULTS: Total lipoproteins and high density lipoprotein significantly increased the release of biliary cholesterol and phosphatidylcholine in plasma and significantly decreased the tissue accumulation of cholesterol absorbed from bile. The scavenger effect of plasma lipoproteins on cholesterol absorbed from bile was concentration dependent. Brefeldin A did not influence gallbladder absorption of biliary cholesterol. CONCLUSIONS: Biliary cholesterol is absorbed by gallbladder mucosa via a Brefeldin-insensitive pathway and is removed by plasma lipoproteins.

Laparoscopic direct supragastric left adrenalectomy.

BACKGROUND: In this paper a novel laparoscopic approach to the left adrenal gland by the transabdominal anterior route is presented. This approach avoids an extensive viscera dissection to gain access to the left adrenal gland. METHODS: The first step of the procedure is the division of the gastrophrenic ligament and the section of 1 or 2 short gastric vessels in order to mobilize the gastric fundus. The gastric fundus is then pulled down, allowing a wide exposure of the left crus of the diaphragm, the perirenal fat, and the superior edge of the pancreatic body. The diaphragmatic-adrenal channel runs on the left crus, crosses the middle adrenal artery, and, usually, joins the left adrenal vein before its junction with the left renal vein. By pulling on the diaphragmatic vein, exposure of the adrenal vein is facilitated. The adrenal vein is then isolated and divided between clips. Using the monopolar electrocautery to control arteries and small veins, the mobilization of the gland is then completed. The adrenal gland is then placed in a plastic bag to prevent cell spillage and removed through an enlarged umbilical incision. RESULTS: During a 20-month period, 6 consecutive patients with left adrenal gland neoplasms have been operated on with the above mentioned original approach. The diameter of the adrenal mass ranged from 3 cm to 6 cm. No conversion to open surgery or complications have been registered. The mean operative time was 126 minutes. The mean length of hospitalization was 4.1 days (range 3 to 6). CONCLUSIONS: This approach offers a complete visualization of the left adrenal gland, avoiding mobilization of the spleen, pancreatic tail, and left flexure of the colon, and allows an early and easy control of the left adrenal vein so adrenalectomy can be safely performed.

"Tension-free" hiatoplasty, gastrophrenic anchorage, and 360 degrees fundoplication in the laparoscopic treatment of paraesophageal hernia.

In our initial experience of four cases from March to November 1994, large paraesophageal hernias were repaired by conventional primary closure of the hiatus with interrupted, nonabsorbable sutures, adding a 360 degrees fundoplication. In all four cases the hernia recurred. Subsequently, we modified the procedure. The technique and results are described. From March 1995 to May 1998, 12 patients with paraesophageal hernia (4 following a previous Nissen procedure) underwent elective laparoscopic repair. In all patients a "tension-free" hiatoplasty and a floppy 360 degrees fundoplication were performed. The hiatal defect was repaired with a polypropylene mesh, fixed to the diaphragm by staples. A gastrophrenic anchorage procedure was added in the eight patients undergoing surgery for the first time, utilizing the peritoneum of the hernia sac. There were no conversions to open surgery or intraoperative complications. Two patients developed postoperative pleural effusion, which was treated medically. Mean hospital stay was 5 days. Three patients developed postoperative transient dysphagia to solid food that lasted 10 days. At a mean follow-up of 22.7 months (range 1-40), all patients are asymptomatic without dysphagia, reflux, or hernia recurrence. Laparoscopic "tension-free" hiatoplasty, 360 degrees fundoplication, and anterior gastrophrenic anchorage are effective in the treatment of large paraesophageal hernias.

Differential effect of stress on gastric somatostatin, prostaglandin E and gastrin release in the rat.

BACKGROUND: The relationship between gastric mucosal damage induced by stress, peptides present in the gastric mucosa and is not clear. Aim of this study was to determine whether cold-restraint stress affected the release of gastric somatostatin, gastrin and in the isolated perfused stomach preparation. METHODS: Male Sprague-Dawley rats were used, 12 cold-restraint stressed and 12 unstressed controls. 4 additional unstressed rats were treated with aspirin (100 mg/kg p.o.). After 30 minutes, isolated stomachs were perfused for 50 minutes with Krebs-Ringer buffer added with isoproterenol or carbamylcholine plus somatostatin-14 or carbamylcholine alone, somatostatin, gastrin and prostaglandin E2 release in the portal vein effluent were measured by radioimmuno-assay. Histology of the gastric mucosa was obtained from a further 4 stressed and 4 unstressed rats. RESULTS: In the stomach from stressed animals, the somatostatin response to isoproterenol and the prostaglandin E2 response to carbamylcholine plus somatostatin were significantly lower than in the controls, whereas gastrin response to carbamylcholine was enhanced by stress. Treatment with aspirin abolished the prostaglandin E2 response to stimulation. Gastric mucosa histology from stressed and unstressed animals showed no significant lesions. CONCLUSIONS: The inhibition of gastric somatostatin and prostaglandins release coupled to an enhanced acid stimulatory influence appear to antidate gastric mucosal injury and should play a role in the stress ulcer genesis.

[Chronic gastritis and prostaglandins. Results of endoscopic screening]. / Gastriti croniche e prostaglandine. Risultati di uno screening endoscopico.

An endoscopic screening was carried out during the period between July 1989 and December 1991 in the Municipality of Roccagorga (LT) in order to: a) evaluate the presence of various forms of gastritis and pre-cancerous lesions; 2) verify the effect of the administration of prostaglandins (Misoprostol) on the evolution of superficial chronic gastritis (CG). A total of 468 endoscopy were performed (17% of the population aged between 20 and 75 years old). 22% of the subjects examined were found to be endoscopically normal; 34% presented symptoms of mild esophagitis and 4% of moderate esophagitis. The prevalence of duodenal ulcer was 10.6% and gastric ulcer 3.4%. Gastric carcinoma was diagnosed in 6 patients (1.2%). 8.5% of patients were found to have atrophic CG and 15.3% superficial CG. Thirty-six patients with superficial CG were randomly divided into two groups: A) treated with Misoprostol 600 mg/day for 6 months; B) controls (placebo). The administration of Misoprostol did not influence the evolution of CG, whereas it caused a reduction in the incidence of type 1 intestinal metaplasia. Misoprostol also led to an improvement in dyspeptic symptoms. The results of the present study do not suggest a role of prostaglandins in the natural evolution of CG.

Effect of nizatidine versus ranitidine on gastric intraluminal prostaglandin release in duodenal ulcer patients.

The role of prostaglandins in peptic ulcer disease and their relation to Helicobacter pylori infection remain controversial. This study sought to compare the effects of oral nizatidine and ranitidine on the gastric mucosal release of prostanoids in duodenal ulcer (DU) patients and to correlate prostanoid concentrations with H. pylori status. Twenty-eight patients with DUs were randomized to receive either nizatidine or ranitidine. Nizatidine 300 mg at night elevated intraluminal PGE2 concentrations; 6-keto-PGF1 alpha concentrations also rose, but did not reach statistical significance. Ranitidine induced non-significant falls in PGE2 and 6-keto-PGE1 alpha concentrations. Patients with H. pylori infection had lower PGE2 and 6-keto-PGF1 alpha concentrations than non-infected patients, but nizatidine was equally effective in increasing prostanoid levels in both groups. These findings may be considered as favourable side effects of nizatidine with uncertain clinical significance. Further studies are needed to elucidate the synergism between prostanoids, eradication of H. pylori and nizatidine in the treatment of DU.

[Laparoscopic cholecystectomy: analysis of first 203 cases]. / Colecistectomia per via laparoscopica: analisi dei primi 203 casi.

Laparoscopic cholecystectomy is a valid alternative to open cholecystectomy. The Authors present their experience in the management of 208 consecutive patients. The low incidence of complications, the short hospital stay as well as earlier return to work, and lower medical expenses are the advantages of laparoscopic surgery. The latter is, therefore, more suitable for the treatment of benign gallbladder diseases.

Basal and somatostatin-stimulated gastric intraluminal prostaglandin E2 in patients with gastric ulcer and with gastric adenocarcinoma.

The effect of somatostatin-14 (SST), at doses utilized in clinical practice, on gastric intraluminal prostaglandin (PG) E2 release was evaluated in 8 endoscopically normal subjects, in 6 patients with benign gastric ulcer and in 8 patients with gastric adenocarcinoma. In normal subjects, SST induced a significant increase in gastric intraluminal PGE2 concentration and output, whereas it did not augment the concentration and output of PGE2 in patients with gastric ulcer and with gastric cancer. The altered PG response to SST stimulation shown by gastric ulcer and gastric cancer patients may be related to a modified cell population in the gastric mucosa and/or to a defective regulation of this local gastric mucosal mediator.

Role of thyrotropin-releasing hormone in stress ulcer formation in the rat.

The role of the hypothalamic peptide thyrotropin-releasing hormone in stress ulcer formation was investigated. In experiment 1, TRH was peripherally administered (10 micrograms/kg) to rats subjected to cold-restraint stress and compared to an inactive peptide; in experiment 2, TRH was administered intracerebroventricularly (0.02, 0.1, and 0.5 microgram/kg) to rats with no adjunctive experimental stress; in experiment 3, TRH antiserum was given intracerebroventricularly to rats subjected to stress and compared to normal rabbit serum. When TRH was administered subcutaneously in rats subjected to stress, it significantly aggravated ulcer formation, and this effect was inhibited by atropine and vagotomy. When administered intracerebroventricularly, TRH alone induced, in a dose-dependent fashion, the formation of gastric ulcers. TRH antiserum infused intracerebroventricularly inhibited ulcer formation induced by cold-restraint stress. In conclusion, TRH seems to play a role in stress ulcer formation, possibly by a cholinergic mediated mechanism.