Poly(2,6-Dimethyl-1,4-Phenylene oxide)/crosslinked polystyrene semi-interpenetrating networks: Synthesis and properties

Semi-interpenetrating networks (semi-IPN's) based on linear poly(phenylene ether)s and crosslinked polystyrene can be prepared by reactive moulding of crosslinkable polymeric mixtures. These materials show thermomechanical properties which strongly depend on both the ratio of the two polymeric matrices and the degree of crosslinking in the polystyrene network. Samples based on a 50/50 weight ratio of poly(2,6-dimethyl-1,4-phenylene oxide)/crosslinked polystyrene show glass transition temperatures (T_g) which are very dependent on the degree of crosslinking. It is therefore possible to obtain materials with desired T_g, ranging from the T_g of the corresponding linear blend to that of poly(2,6-dimethyl-1,4-phenylene oxide) alone.     

Systemic fungemia and hepatic localizations of Fusarium solani in a liver transplanted patient: an emerging fungal agent.

The incidence of invasive fungal infection is increasing especially in the field of transplantation, affecting as many as 50% of bone marrow transplant (BMT) patients with neutropenia and 5-20% of solid-organ transplant (SOT) recipients. Fusarium species are soil saprophytes and plant pathogens. They may cause superficial mycoses or important opportunistic infections in patients with bone marrow suppression and neutropenia, they have been rarely described in solid organ recipients, and up to now there have been no reports of such infection in isolated liver transplanted patients. We describe a case of disseminated Fusarium solani infection with hepatic localization in a liver transplanted patient that resolved with the administration of amphotericin B. Our observation confirms that Fusarium spp. are emerging pathogens that may most frequently affect not only BMT patients and patients with hematological malignancies, but also SOT patients. They may cause both localized and disseminated infection. In conclusion, Fusarium spp. etiology should be considered in the context of infectious diseases following liver transplantation.     

Diagnosis and management of severe atherosclerosis of the ascending aorta and aortic arch during cardiac surgery: focus on aortic replacement

Objective: Severe atherosclerosis of the ascending aorta and arch frequently causes difficulties during heart operations, hindering surgical manoeuvres and potentially leading to systemic embolism. The aim of our study was to assess the safety and effectiveness of replacing the atherosclerotic ascending aorta in this setting. Methods: Aortic atherosclerosis was characterized by epiaortic ultrasonographic scanning in 90.1% of 1927 consecutive adult patients undergoing cardiac operations, and by computed tomographic chest scanning in selected cases. Thirty-six of the 152 patients requiring major derangements from our standard practice due to aortic atherosclerosis underwent replacement of the ascending aorta and constitute the study group. Replacement of the aorta was extended to the arch in 13 cases (36.1%). It was associated with single or multiple valve surgery in 34 patients (94.4%) and with coronary revascularization in 30 (83.3%). Two patients (5.6%) underwent coronary bypass grafting without valve surgery. A cryoablation procedure was associated in three patients with permanent atrial fibrillation. Deep hypothermic circulatory arrest was employed in 34 patients (94.4%), while proximal aortic disease allowed conventional distal crossclamping in 2 cases. The risk of operative mortality was estimated by the logistic EuroSCORE both with and withholding the variable ‘surgery of the thoracic aorta’. All survivors were followed-up for 1–41 months (16 ± 12). Results: Two patients died in the hospital (5.6%) and two during follow-up, for a cumulative survival of 91.3% and 85.6% at 1 and 3 years, respectively (hospital deaths included). The hospital death rate compared favourably with the expected estimates of 25.5% (p < 0.05) and 10.3% (p = 0.67) obtained by the EuroSCORE full model and without ‘aortic surgery’, respectively. In-hospital adverse neurologic events occurred in six patients (16.7%), including stroke in one patient (2.8%) and neurocognitive disturbances in five (13.9%), although they were all transient and cleared before discharge. Excess bleeding required re-exploration in four patients (11.1%), and one more patient underwent emergency grafting for acute postoperative coronary occlusion. Ten patients (38.5%) were intubated for longer than 24 h. Conclusion: Despite significant perioperative morbidity, replacement of the severely atherosclerotic aorta is worth consideration to avert expectedly higher death and stroke rates.     

Modified Subtotal Cholecystectomy: Results of a Laparotomy Procedure During the Laparoscopic Era

Background   Laparoscopic cholecystectomy is now indisputably the gold standard for managing most gallbladder diseases. However, subversion of the Calot triangle anatomy cannot always be managed by laparoscopy and often requires a laparotomy conversion. This report discusses our patients treated with our personal technique. Methods  Patients undergoing subtotal cholecystectomy performed by the same surgeon with a personal technique from January 1999 to December 2007 were considered for the present study. Sex, age, symptoms, co-morbidities, diagnostic modality, time between hospitalization and surgery, length of postsurgical hospitalization, morbidity and mortality, and follow-up were assessed. Results  Four men and six women, aged 23 to 88 years, were included. Every patient had symptoms of acute cholecystitis. Four patients had had symptoms for an average of 2.5 days and six for an average of 5.1 h. All patients were studied by ultrasonography, and seven underwent computed tomography. The operation was performed within 48 h in all patients. The average hospital stay from surgery to discharge was different for patients who underwent primary open cholecystectomy (10 days, range 5–16 days) and those having a conversion after a laparoscopic attempt (7.8 days, range 4–16 days). During the postoperative period only one patient presented a self-limiting biliary leak. No postoperative mortality occurred. At follow-up, any recurrences of stone in the biliary tract or newly formed pouch were recorded. Conclusions  The results suggest that this new approach can be considered effective in every instance of subversion of the normal anatomy of Calot’s triangle.     

Measurement of Pressure-Time Product during Spontaneous Assisted Breathing by Rapid Interrupter Technique

Background: Measuring the work of breathing of patients undergoing spontaneous assisted ventilation can be useful to monitor and titrate ventilatory support. The aim of this study was to obtain measurements of the pressure generated by the respiratory muscles (PMUSC) and the derived pressure-time product (PTP; a good indicator of the metabolic work of breathing), performing the rapid interrupter technique with a commercial ventilator.

Methods: A Draeger Evita 4 ventilator (Draeger Medical, Lubeck, Germany) was controlled by a personal computer to rapidly interrupt the airway flow at different times and volumes of the respiratory cycle during pressure-support ventilation. From the airway pressure tracing after the occlusion, the authors estimated the alveolar pressure and PMUSC; the integration of PMUSC values over the inspiratory time yields the measurement of PTP. Esophageal pressure measurements were used as a reference. After a bench study of the valves' performance, the authors performed 11 measurement sequences in eight patients.

Results: The closure times for the inspiratory and expiratory valves were 74 +/- 10 and 61 +/- 13 ms, respectively. The interrupter technique provided a reliable estimate of PMUSC (PMUSC, occl = 1.00 [middle dot] PMUSC, pes + 0.19; r = 0.88; 95% confidence interval for agreement, +5.49/-5.32 cm H2O). PTPoccl tightly correlated with PTPpes (PTPoccl = 0.95 [middle dot] PTPpes + 0.13; r = 0.96; 95% confidence interval, 1.94/-1.61 cm H2O [middle dot] s).