Effect of the Dianhydride/Branched Diamine Ratio on the Architecture and Room Temperature Healing Behavior of Polyetherimides.

Traditional polyetherimides (PEIs) are commonly synthesized from an aromatic diamine and an aromatic dianhydride (e.g., 3,4'-oxidianiline (ODA) and 4,4'-oxidiphtalic anhydride (ODPA)) leading to the imide linkage and outstanding chemical, thermal and mechanical properties yet lacking any self-healing functionality. In this work, we have replaced the traditional aromatic diamine by a branched aliphatic fatty dimer diamine (DD1). This led to a whole family of self-healing polymers not containing reversible chemical bonds, capable of healing at (near) room temperature yet maintaining very high elastomeric-like mechanical properties (up to 6 MPa stress and 570% strain at break). In this work, we present the effect of the DD1/ODPA ratio on the general performance and healing behavior of a room temperature healing polyetherimide. A dedicated analysis suggests that healing proceeds in three steps: (i) an initial adhesive step leading to the formation of a relatively weak interface; (ii) a second step at long healing times leading to the formation of an interphase with different properties than the bulk material and (iii) disappearance of the damaged zone leading to full healing. We argue that the fast interfacial adhesive step is due to van der Waals interactions of long dangling alkyl chains followed by an interphase formation due to polymer chain interdiffusion. An increase in DD1/ODPA ratio leads to an increase in the healing kinetics and displacement shift of the first healing step toward lower temperatures. An excess of DD1 leads to the cross-linking of the polymer thereby restricting the necessary mobility for the interphase formation and limiting the self-healing behavior. The results here presented offer a new route for the development of room temperature self-healing thermoplastic elastomers with improved mechanical properties using fatty dimer diamines.

The laparoscopic mini-gastric bypass: the Italian experience: outcomes from 974 consecutive cases in a multicenter review.

BACKGROUND: Due to the failure of the "old Mason loop," the mini-gastric bypass (MGB) has been viewed with skepticism. During the past 12 years, a growing number of authors from around the world have continued to report excellent short- and long-term results with MGB. METHODS: One university center, three regional hospitals, and two private hospitals participated in this study. From July 2006 to December 2012, 475 men (48.8 %) and 499 women (51.2 %) underwent 974 laparoscopic MGBs. The mean age of these patients was 39.4, and their preoperative body mass index was 48 ± 4.58 kg/m(2). Type 2 diabetes mellitus (T2DM) affected 224 (22.9 %) of the 974 patients, whereas 291 of the 974 patients (29.8 %) presented with hypertension. The preoperative gastrointestinal status was explored in all the patients through esophagogastroduodenoscopia. The major end points of the study were definitions of both MGB safety and efficacy in the long term as well as the endoscopic changes in symptomatic patients eventually produced by surgery. RESULTS: The rate of conversion to open surgery was 1.2 % (12/974), and the mortality rate was 0.2 % (2/974). The perioperative morbidity rate was 5.5 % (54/974), with 20 (2 %) of the 974 patients requiring an early surgical revision. The mean hospital length of stay was 4.0 ± 1.7 days. At this writing, 818 patients are being followed up. Late complications have affected 74 (9 %) of the 818 patients. The majority of these complications (66/74, 89.1 %) have occurred within 1 year after surgery. Bile reflux gastritis was symptomatic, with endoscopic findings reported for 8 (0.9 %) and acid peptic ulcers for 14 (1.7 %) of the 818 patients. A late revision surgery was required for 7 (0.8 %) of the 818 patients. No patient required revision surgery due to biliary gastritis. At 60 months, the percentage of excess weight loss was 77 ± 5.1 %, the T2DM remission was 84.4 %, and the resolution of hypertension was 87.5 %. CONCLUSIONS: Despite initial skepticism, this study, together with many other large-scale, long-term similar studies from around the world (e.g., Taiwan, United States, France, Spain, India, Lebanon) demonstrated the MGB to be a short, simple, low-risk, effective, and durable bariatric procedure.

[Video laparoscopic adrenalectomy. The authors' personal experience]. / La surrenectomia videolaparoscopica. Esperienza personale.

Personal experience on two cases of laparoscopic adrenalectomy, operated, one on the right and the other on the left side, during 1996 is reported. The surgical technique, using a lateral decubitus and a transperitoneal approach is described, as well as the postoperative outcome. The laparoscopic approach to adrenal surgery seems to be "ideal", since it has a low "trauma ratio" (surgical procedure/access) with an anatomical an virtually bloodless dissection.

[Hemorrhoidectomy with circular stapler in advanced hemorrhoid pathology]. / Emorroidectomia con suturatrice circolare nella patologia emorroidaria avanzata.

The Authors refer their early experience with the treatment of 4th grade haemorrhoids and 4th grade with mucosal prolapse using a circular stapler. The operation is quite easy with a short learning period, with no short term complications and low post-operative pain. The good results need to be confirmed on a large number of cases and a longer follow-up.

Thrombosis of the superior vena cava due to a central catheter for total parenteral nutrition.

Total parenteral nutrition (TPN) today is a fundamental procedure in the treatment of critically ill patients, especially if they have serious gastrointestinal diseases. However, use of the central venous catheter is connected with a very important morbidity. At the "Istituto di Patologia Chirurgica" and at the "Intensive Care Unit" of the University of Ferrara, we analyzed 59 cases of deaths from different diseases, on whom a postmortem examination had been performed. Twenty-seven patients had had no central venous catheter: none of them presented thrombosis of the central veins. Thirty-two patients had had a central venous catheter for TPN: five of them presented thrombosis of the central veins at the post-mortem examination. Except for one case who had thrombosis connected with a carcinoma of the right main bronchus, four cases (12.9%) presented thrombosis due to the central venous catheter. The subclavian vein seems to be more commonly connected with thrombosis than the jugular vein.

Biomaterials and immune system: cellular reactivity towards PTFE and Dacron vascular substitutes pointed out by the leukocyte adherence inhibition (LAI) test.

Thirty-eight patients affected by peripheral vascular insufficiency, and twelve healthy volunteers, were submitted to a cellular immunity test: LAI test, in which leukocytes fail to adhere to glass in contact with a sensitizing antigen. Patients were divided as follows: Class 1: Dacron+PTFE grafted patients, Class 2: Dacron, Class 3: PTFE, Class 4: controls. Total leukocytes, mononuclear cells, T and B lymphocytes were used as cellular populations. Finely minced Dacron and PTFE fabric vascular prostheses were employed as targets. This research showed that a T cellular immune-reactivity towards Dacron and PTFE respectively occurs in Dacron and PTFE grafted patients, and that reactivity is greater in case of Dacron. Wider researches are required to state the immune system role in fabric prostheses patency; at this regard, must be kept in mind that T lymphocytes release thrombogenic factors in course of cellular immune response.

Laboratory findings in acute mesenteric infarction.

A study on the preoperative data of 16 patients with acute mesenteric infarction and the comparison to the pre-operative data of two homogenous groups is reported. The first group includes 11 patients with intestinal necrosis from venous obstruction and the second group includes 10 patients, with mechanical bowel obstruction. From the statistical analysis of the obtained data and the review of current literature it seems possible to obtain a useful differential diagnosis.

False positive diagnosis of bronchogenic carcinoma based on bronchoscopic brushing and sputum cytology. A surgical point of view.

The problem of false positive diagnosis of bronchogenic carcinoma based on bronchoscopic brushing and sputum cytology is analysed. 1071 patients were reviewed, 230 of whom underwent "radical" resection. Diagnoses obtained from bronchoscopic brushing, sputum cytology and microscopic examination of surgical specimens were compared. The statistical analysis of the obtained results showed that "false positives" should be thoroughly evaluated. The concept of cancer in situ and the hypothesis of a multi-step evolution of bronchogenic carcinoma are briefly discussed.

[New prospects offered by echography in the diagnosis of carcinoma of the gallbladder]. / Nuove prospettive offerte dall'ecografia nella diagnosi del carcinoma della colecisti.

Experience in diagnosing several cases of primary carcinoma of the cholecyst echographically in reported. The most important ultrasonic characteristics in relation to staging of the lesion are reviewed. It is seen that echographic features always correlate with surgical findings, confirming the diagnostic accuracy of the method which permits morphofunctional as well as structural evaluation. At this time echography seems to be the most rational tool for efficient diagnosis, a step forward in ensuring timely surgery and the improvement of long term prospects for the condition.