A cloud-based simulation architecture for pandemic influenza simulation.

High-fidelity simulations of pandemic outbreaks are resource consuming. Cluster-based solutions have been suggested for executing such complex computations. We present a cloud-based simulation architecture that utilizes computing resources both locally available and dynamically rented online. The approach uses the Condor framework for job distribution and management of the Amazon Elastic Computing Cloud (EC2) as well as local resources. The architecture has a web-based user interface that allows users to monitor and control simulation execution. In a benchmark test, the best cost-adjusted performance was recorded for the EC2 H-CPU Medium instance, while a field trial showed that the job configuration had significant influence on the execution time and that the network capacity of the master node could become a bottleneck. We conclude that it is possible to develop a scalable simulation environment that uses cloud-based solutions, while providing an easy-to-use graphical user interface.

[Surgical treatment of rectal prolapse with transanal resection according to Altemeier. Experience and results]. / Terapia chirurgica del prolasso del retto mediante resezione transanale secondo Altemeier. Esperienza e risultati.

In recent years the number of patients with partial or total rectal prolapse has increased. Numerous techniques and surgical approaches have been described for its treatment. In this study we examine the main ones and stress the advantages of the transanal-perineal resection technique according to Altemeier and modified by Prasad, which we have used to treat the condition in the last 15 years. From 1988 to 2002, 269 patients with "haemorrhoidal prolapse" were referred to our department; 146 were females (54%), and the mean age was 58 years. Clinical examination and proctosigmoidoscopy revealed the presence of total rectal prolapse in 41 patients (15%, 32 F, 9 M), complicated in 4 cases by moderate incontinence and associated in 3 cases with post-haemorrhoidectomy stenosis. These 41 patients underwent transanal resection according to Altemeier. Thirty-four of them (83%) were operated on under local anaesthesia with sedation, 5 patients (12%) under peridural anaesthesia and 2 patients (5%) under narcosis. The mean hospital stay was 5 days and depended on the time of the first spontaneous evacuation. Check-ups were performed after 7 days, 1 months and every 3 months for 1 year. There was no postoperative mortality, and only 1 case of postoperative haemorrhage, which did not require reoperation, in a patient with a previous myocardial infarct who spontaneously continued to take salicylates up to 24 h before surgery. Thirty-three patients (80%) had their first postoperative evacuation within 48 h of surgery after taking sorbitol orally in the evening, 6 patients (15%) within 72 h, and 2 patients (5%) on postoperative day 4. No evacuative enemas were performed. We observed clinical healing in all patients 1 month after the operation, and regular, spontaneous evacuations without the use of oral laxatives. Stool or gas incontinence were never observed or reported. During the follow-up, only in 2% of cases did we observe partial recurrence of the prolapse. The choice between the numerous surgical techniques for correcting rectal prolapse, depends on the state of the disease, on the patient's general condition and on the surgeon's experience with the various techniques. The perineal approach proposed by Altemeier and modified by Prasad presents a low risk of mortality and immediate complications, as confirmed by our experience, even in high risk patients, and relatively easy execution. It would appear, moreover, to be the only technique capable of correcting the preoperative incontinence sometimes present.

[Role of ultrasonographic imaging in the surgical management of acute diverticulitis of the colon]. / Ruolo dell'imaging ultrasonografico nell'approccio chirurgico alla diverticolite acuta del colon.

Diverticulosis of the colon is a very frequent pathology in the western word and is characterised by a high percentage of dangerous complications (10-25%). The most accurate method of staging diverticular disease is by CT scan. The aim of our study was to evaluate the sensitivity of ultrasonography in the evaluation and management of diverticular disease of the colon. We studied 51 patients: the parameters used to assess complicated diverticulosis of the colon were: 1) wall thickness; 2) presence of fluid collections and pericolic abscesses; 3) free liquid collections in the peritoneal cavity; 4) subdiaphragmatic free air; 5) presence of fistula tracts. Ultrasonography showed 66% sensitivity in the assessment of wall thickness and in detecting the presence of diverticula. The sensitivity rate was 100% in the detection of abscess complications, pericolic collections, free air and fistula tracts. False-negatives (5 patients) were all recorded in Hinchey stage I. The overall sensitivity amounted to 91%. In our experience the method is a first level examination in the approach to patients suffering from diverticular disease of the colon and presents high sensitivity and diagnostic accuracy. The method, in expert hands, is suggested as a first step in the clinical-diagnostic approach to patients suffering from acute abdomen due to diverticulitis of the colon.

[Intraoperative ultrasonography in the staging of pancreatic head neoplasms]. / L'ecografia intraoperatoria nella stadiazione delle neoplasie cefalopancreatiche.

Tumours of the head of the pancreas constitute the fourth most common cause of cancer deaths. These tumours are characterised by low survival rates (5% at 5 years) and low surgical resectability rates (20-25%). Liver metastases, lymph-node and vascular involvement, and peritoneal metastases are, in our opinion, exclusion criteria for curative surgical resection. The aim of the study was to evaluate the impact of intraoperative ultrasonography on the staging of such tumours. Over the period from 1990 to 2000 we introduced intraoperative ultrasonography in the staging of pancreatic cancer. We evaluated 51 patients who at preoperative staging had been regarded as candidates for surgical therapy consisting in a pancreaticoduodenectomy. All patients had been staged by preoperative abdominal ultrasound, ERCP, CT and MRI. Intraoperative ultrasound and colour-Doppler imaging (from 1997 on) revealed involvement of (i) the liver, (ii) the splenomesenteric vessels and (iii) the portal vein. Intraoperative ultrasonography yielded a diagnosis of occult liver metastases in 10 cases and signs of vascular involvement (absence of cleavage, partial and total thrombosis) in 12. One false-negative was registered. Intraoperative ultrasonography in our experience showed 98% sensitivity and specificity in the detection of vascular and lymph-node involvement. Its sensitivity in the detection of liver metastases was 100%. Intraoperative ultrasound is a procedure with a very high sensitivity in the operative staging of cancer of the head of the pancreas.

[Mucin-secreting tumor of the appendix with large gelatinous effusion]. / Tumore mucosecernente dell'appendice con cospicuo versamento gelatinoso.

The authors report a case of a mucinous tumour of the appendix with a large muco-gelatinous effusion detected as a result of massive abdominal compression. The mucinous mass occupied the entire abdominal cavity and was compressing the abdominal vascular trunks. Increases in CEA, Ca 19.9 and Ca 50 were recorded. The abdominal CT scan was of fundamental importance for diagnosing the condition. Surgery was performed consisting in removal of the mucinous abdominal mass, the appendix and part of the caecum. The postoperative course was favourable with rapid restoration of abdominal organic functions and normalisation of CEA. The rarity of these tumours is stressed.

[Radiofrequency ablation in primary and secondary liver tumors]. / La termoablazione mediante radiofrequenza delle neoplasie primitive e secondarie del fegato.

The authors report the preliminary results of a new treatment for primary and secondary hepatic malignancies called radiofrequency ablation. Seven patients undergoing the new radiofrequency ablation procedure (4 M and 3 F; mean age 62 years) were studied. The 3 female patients were suffering from breast cancer metastases (1 case), left colon cancer metastases to the first hepatic segment with caval and portal compression (1 case), and metastases to the eighth hepatic segment from an operated left colon cancer (1 case). The 4 male patients were suffering from carcinoma of the first hepatic segment on a cirrhotic liver (1 case), two liver metastases from left a colon cancer (1 case), a single 3-cm diameter metastasis treated by laparotomic radiofrequency ablation after resection of a gastric cancer (1 case), and one metastasis to the eighth hepatic segment from an operated left colon cancer (1 case). Prior to treatment all patients were subjected to investigation of routine blood-chemistry parameters, hepatic enzymes, cancer markers (Ca 19.9, alphafetoprotein, cytokines), abdominal spiral CT or MRI or PET (18 FDG); and thorough ultrasonography. Four patients underwent percutaneous radiofrequency ablation; one patient with concomitant gastric cancer underwent laparotomic radiofrequency ablation and simultaneous removal of the tumour; one patient was treated by celioscopic radiofrequency ablation in the course of laparoscopic cholecystectomy; and one underwent transpleural-diaphragmatic radiofrequency ablation for metastases to the seventh and eighth hepatic segments. None of the patients undergoing ultrasonography and CT follow-up examinations after 6 months presented recurrence of hepatic metastases. This treatment, though its use has so far been limited to only a few cases with a short follow-up, opens up new prospects for the surgical treatment of primary and secondary malignancies, also in the light of experience based on a substantial number of patients, recently reported in the literature.

[Surgical treatment of acute respiratory failure caused by mediastinal goiter. Clinical experience and results]. / Il trattamento chirurgico della insufficienza respiratoria acuta da gozzo mediastinico. Esperienza clinica e risultati.

In the regions where goitre is endemic, onset of the disease with acute respiratory insufficiency caused by thyroid compression is an uncommon situation requiring a rapid diagnosis and urgent surgical treatment. From January 1997 to December 2000 we observed 81 patients with thyroid pathologies, (69 males and 12 females; mean age 64 years). We found colloid-cystic goitre in 39 cases, adenomatous goitre in 26, carcinoma in 12, Hürthle's cell tumours in 3 and inflammatory disease in 1. All patients underwent thyroidectomy. Nine patients (11%) presented acute respiratory insufficiency caused by thyroid compression, with various associated phonesis disorders; in these cases we performed emergency surgery with postoperative maintenance of tracheal intubation or tracheotomy or the possible positioning of a self-expanding tracheal stent. In these 9 patients there were 4 deaths (44%), 3 in the immediate postoperative period and one after 10 months. We also observed one hydropneumothorax. Functional recovery was achieved in the remaining 5 patients. The treatment of this clinical picture requires urgent tracheal intubation, before the use of diagnostic tools, and it is important to maintain it after the surgical procedure for as long as is necessary for the tracheal wall to be reconstituted. In the severest cases a temporary tracheotomy is needed or the positioning of a tracheal stent, which offers a valid and effective alternative.

[Surgical treatment of anal stenosis following hemorrhoid surgery. Results of 150 combined mucosal advancement and internal sphincterotomy]. / Il trattamento chirurgico delle stenosi anali post-emorroidectomia. Risultati di 150 interventi di anoplastica per scorrimento mucoso e sfinterotomia interna.

The aim of the study was to evaluate the efficacy of anoplasty by mucosal advancement combined with internal sphincterotomy for the treatment of iatrogenic anal stenosis. From January 1990 to December 2000, 149 patients with post-haemorrhoidectomy anal strictures underwent internal sphincterotomy and mucosal advancement flap anoplasty. Seventy-one percent of patients were operated on under local anaesthesia by perineal block according to Marti. In 90 percent of the patients, postoperative pain was mild. No significant complications were seen. The mean hospital stay was two days. Ninety-seven percent of patients were well satisfied with the surgical result one year after operation. Current surgical options for the treatment of post-haemorrhoidectomy anal stricture are reported and the advantages of mucosal advancement flap anoplasty outlined.