The use of electrospun polymeric biodegradable materials for medical applications is becoming increasingly widespread. One of the most important parameters regarding the functionality of nanofiber scaffolds during implantation and the subsequent regeneration of damaged tissues concerns their stability and degradation behavior, both of which are influenced by a wide range of factors (the properties of the polymer and the polymer solution, the technological processing approach, the sterilization method, etc.). This study monitored the degradation of nanofibrous materials fabricated from degradable polyesters as a result of the sterilization method applied (ethylene oxide and gamma irradiation) and the solvent system used to prepare the spun polymer solution. Aliphatic polyesters PCL and PLCL were chosen for this study and selected with respect to the applicability and handling in the surgical setting of these nanofibrous materials for vascular bandaging. The results revealed that the choice of solvent system exerts a significant impact on degradation during sterilization, especially at higher gamma irradiation values. The subsequent enzyme-catalyzed degradation of the materials following sterilization indicated that the choice of the sterilization method influenced the degradation behavior of the materials. Whereas wave-like degradation was evident concerning ethylene oxide sterilization, no such behavior was observed following gamma-irradiation sterilization. With concern for some of the tested materials, the results also indicated the potential for influencing the development of degradation within the bulk versus degradation from the surface of the material. Both the sterilization method and the choice of the spinning solvent system were found to impact degradation, which was observed to be most accelerated in the case of PLCL (L-lactide-co-caprolactone copolymer) electrospun from organic acids and subsequently sterilized using gamma irradiation. Since we planned to use these materials in cardiovascular applications, it was decided that their hemocompatibility would also be tested. The results of these tests revealed that changes in the structures of the materials initiated by sterilization may exert thrombogenic and anticoagulant impacts. Moreover, the microscopic analysis suggested that the solvent system used in the preparation of the materials potentially affects the behavior of erythrocytes; however, no indication of the occurrence of hemolysis was detected.
The aim of the study was to develop an orthopedic implant coating in the form of vancomycin-loaded collagen/hydroxyapatite layers (COLHA+V) that combine the ability to prevent bone infection with the ability to promote enhanced osseointegration. The ability to prevent bone infection was investigated employing a rat model that simulated the clinically relevant implant-related introduction of bacterial contamination to the bone during a surgical procedure using a clinical isolate of Staphylococcus epidermidis. The ability to enhance osseointegration was investigated employing a model of a minipig with terminated growth. Six weeks following implantation, the infected rat femurs treated with the implants without vancomycin (COLHA+S. epidermidis) exhibited the obvious destruction of cortical bone as evinced via a cortical bone porosity of up to 20% greater than that of the infected rat femurs treated with the implants containing vancomycin (COLHA+V+S. epidermidis) (3%) and the non-infected rat femurs (COLHA+V) (2%). The alteration of the bone structure of the infected COLHA+S. epidermidis group was further demonstrated by a 3% decrease in the average Ca/P molar ratio of the bone mineral. Finally, the determination of the concentration of vancomycin released into the blood stream indicated a negligible systemic load. Six months following implantation in the pigs, the quantified ratio of new bone indicated an improvement in osseointegration, with a two-fold bone ingrowth on the COLHA (47%) and COLHA+V (52%) compared to the control implants without a COLHA layer (27%). Therefore, it can be concluded that COLHA+V layers are able to significantly prevent the destruction of bone structure related to bacterial infection with a minimal systemic load and, simultaneously, enhance the rate of osseointegration.
22 March 2019 in World Journal of Surgical Oncology
Mixed neuroendocrine-non-neuroendocrine tumors (MINEN) of the gallbladder are extremely rare; indeed, the English expert literature reports a mere handful of case reports and case series on this topic. According to the WHO classification of 2010, MINEN are considered to be tumors consisting of two major components, neuroendocrine and non-neuroendocrine, each of which hosts at least 30% of the total cellular population. To date, the etiology and pathogenesis of MINEN have not been precisely determined and the non-specific symptoms generally result in late diagnosis (mainly in the terminal stages of the condition) and contribute to the generally poor prognosis. As far as the management of the disease is concerned, radical surgery plays a crucial role; however, the significance of surgical debulking and biological therapy applying somatostatin analogues has not yet been determined. A 56-year-old female was referred to our department for a rapidly progressing tumor in the subhepatic area along with the infiltration of S5 and S6 liver segments. With regard to preoperative findings, the tumor appeared as operable, although, during the surgery, an extensive involvement of the hepatoduodenal ligament by the tumor through the lymph nodes was revealed. Due to acute perioperative bleeding from the necrotic tumor, we decided to perform modified resection. Histologically, the tumor was confirmed as MINEN of gallbladder, where the neuroendocrine component was dominant over the non-neuroendocrine component. Six weeks after the discharge, the patient underwent a follow-up CT revealing large recurrence of the disease. Thereafter, the patient was started on systemic therapy with etoposide and carboplatin in combination with somatostatin analogues. Thirteen months after the surgery, the patient is in good clinical condition, and while a recently performed PET/MRI scan revealed a hepatic lesion and hilar lymphadenopathy in full regression, there was a spread of small peritoneal and pleural metastases. The patient remains in the follow-up care. The occurrence of mixed neuroendocrine-non-neuroendocrine neoplasms is extremely rare. Radical surgery remains the only potentially effective approach to the cure of this disease. The role of biological therapy and debulking in the management of the disease has not yet been precisely defined. In our experience, both of these methods have the potential to positively influence overall survival rates and the postoperational quality of life of patients.
Cardiac damage is one of major cause of worldwide morbidity and mortality. Despite the development in pharmacotherapy, cardiosurgery and interventional cardiology, many patients remain at increased risk of developing adverse cardiac remodeling...