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.

Monitoring Network and Interfacial Healing Processes by Broadband Dielectric Spectroscopy: A Case Study on Natural Rubber.

Broadband dielectric spectroscopy (BDS) is introduced as a new and powerful technique to monitor network and macroscale damage healing in an elastomer. For the proof of concept, a partially cured sulfur-cured natural rubber (NR) containing reversible disulfides as the healing moiety was employed. The forms of damage healed and monitored were an invisible damage in the rubber network due to multiple straining and an imposed macroscopic crack. The relaxation times of pristine, damaged, and healed samples were determined and fitted to the Havriliak-Negami equation to obtain the characteristic polymer parameters. It is shown that seemingly full mechanical healing occurred regardless the type of damage, while BDS demonstrates that the polymer architecture in the healed material differs from that in the original one. These results represent a step forward in the understanding of damage and healing processes in intrinsic self-healing polymer systems with prospective applications such as coatings, tires, seals, and gaskets.

A time bomb in the thorax: the giant ascending aortic aneurysm: case report.

We report the case of a 82-year-old woman, asymptomatic, subject to chest computed tomography for trauma. Then the patient underwent surgery. Before sternotomy, femoro-femoral bypass was starter in order to decompress the aneurysm; using deep hypothermia and circulatory arrest, ascending aorta and hemiarch replacement were performed with a Dacron graft. Post-operative course was uneventful.

Management of anaplastic thyroid carcinoma spread over the trachea with mediastinal extension.

INTRODUCTION: We report a case of treatment of anaplastic thyroid carcinoma spread over the trachea with mediastinal extension. METHODS: Case report and review of the world literature concerning the treatment of anaplastic thyroid carcinoma are presented. DISCUSSION: The role of surgery in treatment of anaplastic carcinoma remains controversial. Our case we underlined two questions: the appropriateness of the surgery options with extra-thyroid spread and the better surgery approach to anaplastic thyroid carcinoma interesting the mediastinum controlling the great vessels of the neck. Even if curative resection cannot be achieved, surgical resection can immediately reduce the tumor bulk to facilitate the efficacy of post-operative radiotherapy and/or chemotherapy and to achieve a good local control to avoid the need of a subsequent palliative tracheostomy. Tumor upper mediastinal involvement made mandatory to open the sternum in order to allow a more complete resection of the macroscopic mass. The mini-sternotomy represents a valuable alternative that allows reduction in surgical trauma increasing patient's comfort. CONCLUSION: The complete resection of the tumor mass without scarifying vital structures can lead to some prolonged survival. Even if complete resection cannot be achieved, surgical resection can immediately reduce the tumour bulk and achieve good local control of the disease to avoid the palliative tracheotomy.

Early-onset subicular microvascular amyloid and neuroinflammation correlate with behavioral deficits in vasculotropic mutant amyloid beta-protein precursor transgenic mice.

Cerebral microvascular amyloid beta protein (Abeta) deposition and associated neuroinflammation are increasingly recognized as an important component leading to cognitive impairment in Alzheimer's disease and related cerebral amyloid angiopathy (CAA) disorders. Transgenic mice expressing the vasculotropic Dutch/Iowa (E693Q/D694N) mutant human Abeta precursor protein in brain (Tg-SwDI) accumulate abundant cerebral microvascular fibrillar amyloid deposits exhibiting robust neuroinflammation. In the present study, we sought to determine if the unique amyloid pathology of Tg-SwDI mice was associated with deficits in behavioral performance. Behavioral performance tests that assessed a variety of psychological functions, including overall activity, motor ability, balance and strength, anxiety, impulsivity, and learning were conducted on homozygous Tg-SwDI mice and similarly aged wild-type C57Bl/6 mice. Our results indicate that Tg-SwDI mice were impaired in the performance of the Barnes maze learning and memory task at 3, 9, and 12 months of age. While more widespread cerebral microvascular Abeta pathology was evident in older animals, the evaluation of the Abeta pathology in the 3 months old transgenic animals revealed specific accumulation of microvascular amyloid and markedly elevated numbers of reactive astrocytes and activated microglia restricted to the subiculum. These findings indicate that early-onset accumulation of subicular microvascular amyloid and accompanying neuroinflammation correlates with impaired performance in the learning and memory task in Tg-SwDI mice.

Post-traumatic pseudoaneurysm of internal mammary artery: a case report.

Pseudoaneurysm of the internal mammary artery can be a rare complication of surgery, particularly post-sternotomy, or determined by a direct trauma, usually a stab wound. This report presents a pseudoaneurysm by a stab, diagnosed by chest computed tomography scan performed for hemothorax recurrence. The patient underwent left thoracotomy in third intercostal space; mammary vessels were identified above and below the pseudoaneurysm sac and tied. The postoperative course was uneventful.

Solitary cardiac metastasis from a clear cell carcinoma of the kidney. A case report and review of the literature.

A case of solitary septal metastasis from a clear cell carcinoma of the kidney is reported in a 55-year-old man who 5 years before had undergone right nephrectomy and adrenalectomy. Since then, he had been successfully treated by means of chemotherapy, radiation therapy, or operated on, at almost yearly intervals, for secondary pancreatic, pulmonary and cerebral single metastases. Diagnosis was obtained by routine computed tomography. The septal mass was surgically removed and the patient was discharged on the 4th postoperative day.

Heart transplantation in chemotherapeutic dilated cardiomyopathy.

Anthracycline cardiotoxicity can induce dilated cardiomyopathy (DCM). Nine patients (four men) experienced postchemotherapy DCM: age at time of tumour diagnosis ranged from 1-45 years (mean 13.5 +/- 19 years); interval time between tumour and HT was 3-23 years (mean 10.8 +/- 6.6) and age at HT ranged from 10-65 years (30.8 +/- 20.1). Interval between end of chemotherapy and beginning of cardiac symptoms was 5.71 +/- 4.6 years. Mean age at DCM diagnosis was 19.2 +/- 19.7 (range 1-50 years). Interval between start of chemotherapy and DCM ranged from 1 month to 10 years (mean 3.15 +/- 3.6 years). Tumours were Ewing sarcoma (7-year-old boy), paratesticular rabdomyosarcoma (1-year-old boy), Wilms tumor with pulmonary metastasis (3-year-old girl), bilateral breast carcinoma (45-year-old woman), uterine leiomyosarcoma (44-year-old woman), acute myelocytic leukemia (1.5-year-old boy and 17-year-old girl), and chronic myelocytic leukemia (5-year-old boy). All patients had high pulmonary resistance values. One patient with chronic myelocytic leukemia (14 year-old at HT) died due to graft failure on the first postoperative day. At follow-up (mean, 80.4 +/- 69.3 months) two patients died: a 32-year-old woman (acute myelocytic leukemia) 1 year after HT for sepsis and a 68-year-old woman who had breast adenocarcinoma recurrence 81 months after HT. The remaining patients are alive, in good condition with no difference in survival from other transplanted patients (P =.757). Patients with end-stage postchemotherapy DCM without evidence of tumour recurrence can safely undergo HT.

Lung transplantation in a Jehovah's witness. Case report in a twinning procedure.

Jehovah's Witnesses, patients who refuse blood transfusions, are generally not considered as candidates for lung transplantation owing to the frequent requirement for transfusions. A successful procedure in a Jehovah's Witness is presented and to our knowledge this is the 2(nd) reported case. The patient, a 38-year-old female, type I diabetes, affected by idiopatic pulmonary fibrosis underwent left lung transplantation. From the same pulmonary bloc a twinning procedure was obtained by means of right lung transplantation in a 58-year-old man affected by the same pathology. Surgical strategies employed in achieving a successful outcome, ethical and moral aspects are discussed.

[Pharmacological sympathetic block in complex regional pain syndrome]. / Blocco farmacologico del simpatico nella Complex Regional Pain Syndrome.

PURPOSE: The Complex Regional Pain Syndrome (CRPS) is a chronic pain state provoked by lesions of the soft tissues or of the bony tissues (type CRPS-I or reflex sympathetic dystrophy-RSD) or by lesions of the nerves (type CRPS-II or causalgia) with vegetative alterations (perspiration, vasomotory alterations) and trophic alterations (bony cutaneous atrophy, alopecia, articular contractures). The pharmacological block of the sympathetic nerves through a peripheral vein is inserted in the multidisciplinary approach that characterizes the therapy of this syndrome. MATERIALS AND METHODS: A retrospective survey was carried out on a group of 185 patients affected by RDS/CRPS with block of the sympathetic nerves through a peripheral vein with guanethidine. Superior limb: Inflation of the tourniquet till disappearance of the radial wrist. Cannulation of a peripheral vein with Butterfly needle n. 23. Guanethidine 10 mg, lidocaine 20 mg, sodic heparin 500 u.i, NaCl 0.9% 20 ml. Injection in 5 minutes. Permanence of the pneumatic tourniquet inflated above systolic blood pressure for 15 minutes. Deflation slowly. Inferior limb: Inflation of the tourniquet till disappearance of the pedidium wrist. Cannulation of a peripheral vein with Butterfly needle n. 23. Guanethidine 20 mg, lidocaine 40 mg, sodic heparin 1000 u.i, NaCl 0.9% 40 ml. Injection in 5 minutes. Permanence of the pneumatic tourniquet inflated above systolic blood pressure for 15 minutes. Deflation slowly. RESULTS: The first stage (hyperemic) showed the highest incidence of remissions: (83, 33%). Even in the second stage (dystrophic) the answer to the therapy has been fundamentally positive: (53, 68%). In the third stage (atrophic) the results have been more modest: (8, 33%). CONCLUSIONS: The block of sympathetic system with guanethidine is still an important method in the therapy of the CRPS; in fact it is surely less invading than the blocks of the stellate ganglion or of the lumbar sympathetic.

Orthotopic heart transplantation: standard versus bicaval technique.

We compared orthotopic heart transplantation (HT) by bicaval technique with the standard technique. Between January 1995 and December 1997, 117 patients underwent 118 HTs; 71 patients (15 women and 56 men) had 72 HTs by standard technique and 46 patients (9 women, 37 men) underwent HT using bicaval procedures. Preoperative parameters were similar in both groups; 5 patients who underwent the standard technique and no patients who underwent bicaval procedures required permanent pacemakers (p = NS). Isoproterenol infusion was significantly longer in the standard technique. Major perioperative arrhythmias (ventricular tachycardia and fibrillation, asystole) appeared in 8.2% and 7.0% of standard and bicaval HTs, respectively; atrial fibrillation appeared in 13.1% and 4.6%, respectively (p = NS). At 1 month, mitral and tricuspid regurgitation rates were higher in the standard group (p = NS); at 1 year only tricuspid regurgitation was still higher (p = NS). Right atrial pressure, Wood units, cardiac output, and cardiac index were examined (p = NS). At multivariate analysis, interaction between preoperative Wood units and transplant type was elicited for Wood units at 1 month and for right atrial pressure at 1, 3, and 6 months. In the high resistance subgroup, the patients who underwent bicaval procedures had higher resistances at 1 month. In the low resistance subgroup, right atrial pressure was higher in patients who underwent standard techniques at 1, 3, and 6 months follow-up. Thus, bicaval HT was found to be safe, without surgically related complications, it provoked significantly less blood loss, and required less isoproterenol use. No significant advantages were observed in conduction disturbances and major arrhythmias or regarding the need for temporary or permanent pacemakers.

The spectrum of aortic complications after heart transplantation.

BACKGROUND: The connection between the donor and the recipient aorta is a potential source of early and late complications as a result of infection, compliance mismatch, and technical and hemodynamic factors. Moreover, the abrupt change in systolic pressure after heart transplantation involves the entire thoracic aorta in the risk of aneurysm formation. The aim of this study was to analyze the types of aortic complications encountered in our heart transplantation series and to discuss etiology, diagnostic approach, and modes of treatment. METHODS: Of the 442 patients having orthotopic heart transplantation and the 11 patients having heterotopic heart transplantation at our center, 9 (2%) sustained complications involving the thoracic aorta. These 9 patients were divided into four groups according to the aortic disease: acute aortic rupture (2 patients); infective pseudoaneurysm (3 patients); true aneurysm and dissection of native aorta (2 patients); and aortic dissection after heterotopic heart transplantation (2 patients). Surgical intervention was undertaken in 8. RESULTS: Five (83%) of 6 patients who underwent surgical treatment for noninfective complications survived the operation, and 4 are long-term survivors. One patient who underwent a Bentall procedure 71/2 years after heterotopic heart transplantation died in the perioperative period of low-output syndrome secondary to underestimated chronic rejection of the graft. One patient with pseudoaneurysm survives without surgical treatment but died several years later of cardiac arrest due to chronic rejection. Both patients operated on for evolving infective pseudoaneurysm died in the perioperative period. CONCLUSIONS: Infective pseudoaneurysms of the aortic anastomosis are associated with a significant mortality. In noninfective complications, an aggressive surgical approach offers good long-term results. The possibility of retransplantation in spite of complex surgical repair should be considered in the late follow-up after heart transplantation, due to the increasing incidence of chronic rejection.

Heart transplantation in ischemic heart disease when recipients are older than 55 years and donors older than 50.

The purpose of this article is to analyze patients affected with ischemic cardiomyopathy, older than 55 years, who have undergone heart transplantation. We conducted a retrospective analysis comparing clinical course and outcome in patients whose donor age was > or = 50 years (Group A) with patients who had younger donor heart (Group B). Group A was composed of 25 patients, 55 to 68 years old (27.4% of the patients), 20 males and 5 females; Group B was composed of 68 patients, 55 to 66 years old, 65 males and 3 females. Mean donor age in Group A was 54.7 years old (range 51-61), while in Group B it was 29.5 years old (range 9-49). Operative mortality was 16% (4 cases) and 12% in Group B (8 cases) p = ns. Total mortality in Group A was 24%, or 6 cases: 2 graft failures, 1 infection, 1 neoplasm, 1 multiorgan failure, 1 ischemic heart disease; in Group B it was 27%, or 18 cases: 2 cerebrovascular accidents, 4 graft failures, 3 infections, 5 neoplasms, 3 multiorgan failures, 1 acute rejection, p = ns. Coronarography was performed in 51 patients, 14 in Group A (10 cases normal, 3 with irregularities, and 1 case with a critical stenosis of the circumflex artery; 37 in Group B (32 cases were normal, 3 had irregularities and 2 had critical stenosis in a coronary artery). In conclusion, we emphasize that extending donor age in recipients older than 55 years of age does not determine a higher risk and mortality.

Risk factors for early death in patients awaiting heart-lung or lung transplantation: experience at a single European center.

BACKGROUND: Our purpose was to establish whether patients on the waiting list for heart-lung or lung transplantation had different survival rates according to diagnosis and to determine the specific variables responsible for early death. METHODS: Between 1988 and 1996, 278 patients were placed on the waiting list for organ transplant. Diagnoses were pulmonary vascular disease in 128, parenchymal disease in 141, and retransplantation in 9 patients. Eighty patients received transplants, 100 patients died awaiting transplantation, and 98 patients are still awaiting transplantation. Univariate and multivariate analyses of risk factors for early death on the waiting list were performed. Patients still listed < or =6 months (n=24), transplanted < or =6 months (n=37), or in the retransplantation group (n=9) were excluded. Of the remaining 208 patients, 52 died < or =6 months and 156 survived >6 months. RESULTS: Patients with primary pulmonary hypertension, pulmonary fibrosis, or cystic fibrosis had statistically significantly lower survival rates at 6, 12, and 24 months (31%, 36% and 26%, respectively, at 24 months) than patients with Eisenmenger's syndrome and chronic obstructive pulmonary disease (76% and 71%). Patients with Eisenmenger's syndrome who died < or =6 months had significantly higher systolic pulmonary artery pressure (134+/-39 vs. 108+/-25 mmHg) and pulmonary vascular resistance (1928+/-1686 vs. 1191+/-730 dyn/sec/cm(-5)) than those who survived longer. Patients with pulmonary fibrosis who died < or =6 months had significantly lower forced vital capacity (36+/-15 vs. 47+/-13% predicted), forced expiratory volume (37+/-14 vs. 48+/-14% predicted), room air PO2 (42+/-11 vs. 50+/-11 mmHg), and room air O2-saturation (78+/-10 vs. 84+/-8%) than those who survived longer. In the multivariate analysis, only the type of pathology was a significant risk factor for death after being on the waiting list < or =6 months. CONCLUSIONS: Certain pathologies and variables are risk factors for early death in patients on the waiting list. This information may be used to allocate specific donor organs to patients in greater need.

Echo-guided endomyocardial biopsy in heterotopic heart transplantation. Case report.

Right ventricular endomyocardial biopsy is difficult to perform in patients who underwent heterotopic heart transplantation because of the complex vascular anatomy. The procedure is usually performed under fluoroscopic control. We present a case of a 59-year-old woman that after heterotopic heart transplantation underwent echo-guided endomyocardial biopsy. We report the technique discussing data obtained in other 11 patients heart transplanted in the heterotopic way. In conclusion we believe that echocardiographic guidance during endomyocardial biopsy allows a better choice of bite sites, reduces the risk of free wall perforation. Moreover is diminished the risk of X-ray exposure to both patient and operator.

Heart transplantation without informed consent: discussion of a case.

OBJECTIVE: To discuss informed consent to heart transplantation in the case of an intensive care unit (ICU) patient: relatives' informed consent was refused by the patient himself whose cognitive ability appeared to be reasonable for the purpose. SETTING: ICU of a university teaching hospital. PATIENT: A 62-year-old man who underwent myocardial revascularization had in the immediate post-operative hemodynamic instability, continuous serious arrhythmias, ventilatory support, fentanyl infusion. Heart transplantation could be the only chance for his survival. INVENTION: Heart transplantation. RESULTS: Despite patient's refusal, we decided to hold the relative's consent as valid, and transplantation was accordingly performed, to the subsequent satisfaction of the patient. CONCLUSIONS: Our decision was based on two beliefs: (1) the severity of the patient's clinical condition may have impaired his cognitive abilities; (2) the very same conditions may mask impairment and certainly make reliable assessment of cognition and judgment impossible. This being so, the preservation of life assumes priority.