The corrosion and cell viability behaviors of nanostructured, nickel-free stainless steel implants were studied and compared with AISI 316L. The electrochemical studies were conducted by potentiodynamic polarization and electrochemical impedance spectroscopic measurements in a simulated body fluid. Cytocompatibility was also evaluated by the adhesion behavior of adult human stem cells on the surface of the samples. According to the results, the electrochemical behavior is affected by a compromise among the specimen's structural characteristics, comprising composition, density, and grain size. The cell viability is interpreted by considering the results of the electrochemical impedance spectroscopic experiments.
Background Laparoscopic staging is rapidly evolving as an important surgical approach in the field of gynecology oncology. However, the specific learning curve associated with this approach remains poorly investigated. This study aimed to evaluate the learning curve for laparoscopic staging of uterine cancers. Methods A series of 28 consecutive laparoscopic hysterectomies with or without pelvic and/or para-aortic lymph node sampling for the treatment of early and locally advanced endometrial or cervical cancer were performed between July 2008 and January 2011. The analyses of the learning curves of the institution were performed for 20 patients who had undergone pelvic lymphadenectomy and/or para-aortal lymph node sampling. The learning curve period has also been compared with the last 26 patients who received laparotomy staging (“open” group) due to the same diagnosis and by the same surgical team. To assess the short- and long-term outcomes, we used validated questionnaires to record the clinical and follow-up results, any complaints or subjective reports from the patients, and details of their quality of life. All data were collected prospectively in a database and reviewed retrospectively. The learning was evaluated using the cumulative sum (CUSUM) method. Results The CUSUM learning curve consisted of two distinct phases: phase 1 (the initial 9 cases) and phase 2 (the subsequent cases) which presented the mastery phase, with the operative time of 397.7 ± 63.5 versus 300.6 ± 19.4 min (p < 0.0001). The significance of the difference between the two phases and “open” group changed in terms of number of lymph nodes retrieved, intra-operative blood loss and hospital stay. The conversion rate of phase 1 was higher than phase 2 [2 (22.2 %) respectively 1 (9 %)]. Conclusions This series confirms previous study findings concerning the feasibility and the safety of laparoscopic staging and provides information for surgeons in single centers considering adopting an endoscopic strategy to monitor the different aspects of outcomes during the implementation process for internal benchmarking. The operative outcome of laparoscopic staging intervention improves with experience. The data reported in this article suggest that after a learning curve of 9 patients, a relevant improvement at least regarding the duration of the operation can be achieved for experienced surgeons who start performing laparoscopic staging of uterine cancers. However, due to the limited number of patients as well as number of para-aortic lymph node sampling procedures, further studies are required for firm conclusions to be drawn.
30 June 2011 in Nephrology Dialysis Transplantation
Background. In kidney transplantation (KTx), vascular thrombosis has a major impact on morbidity and graft survival. The ischaemia, caused by thrombosis, can lead to interstitial metabolite changes. The aim of this experimental study was to create conditions in which the graft would be prone to vascular thrombosis following KTx and then to evaluate the role of microdialysis (MD) for its early detection. Methods. Sixteen randomized pigs in the control group received heparin and immunosuppressive drugs, while the case group received none. Based on histopathological evidence of vascular thrombosis, the case group was subdivided into mildly and severely congested subgroups. Using MD, we evaluated the interstitial concentrations of glucose, lactate to pyruvate ratio, glutamate and glycerol in the transplanted grafts during different phases of KTx. Results. Following reperfusion, we noted considerable changes. The severely congested subgroup showed a low and decreasing level of glucose. Only in this group did the lactate to pyruvate ratio continue to increase until the end of monitoring. The glycerol level increased continuously in the entire case group and this increase was most significant in the severely congested subgroup. In all of the study groups, glutamate concentration remained in a low steady state until the end of monitoring. Conclusion. MD can be an appropriate method for early detection of vascular complications after KTx. Decreasing glucose levels, increased lactate to pyruvate ratio and increased glycerol levels are appropriate indicators for early detection of vascular thromboses following KTx. Particularly, the glycerol level could predict the necessity and urgency of intervention needed to ultimately save the transplanted kidney.
Ovarian cancer (OC) accounts for approximately 4% of cancer deaths in women worldwide and is the deadliest gynecologic malignancy. High-grade serous ovarian cancer (HGSOC) is the most predominant ovarian cancer, in which BRCA1/2 gene mutation ranges from 3 to 27%. PARP inhibitors (PARPi) have shown promising results as a synthetically lethal therapeutic approach for BRCA mutant and recurrent OC in clinical use. However, emerging data indicate that BRCA-deficient cancers may be resistant to PARPi, and the mechanisms of this resistance remain elusive. We found that amplification of KRAS likely underlies PARPi resistance in BRCA2-deficient HGSOC. Our data suggest that PLK1 inhibition restores sensitivity to PARPi in HGSOC with KRAS amplification. The sequential combination of PLK1 inhibitor (PLK1i) and PARPi drastically reduces HGSOC cell survival and increases apoptosis. Furthermore, we were able to show that a sequential combination of PLK1i and PARPi enhanced the cellular apoptotic response to carboplatin-based chemotherapy in KRAS-amplified resistant HGSOC cells and 3D spheroids derived from recurrent ovarian cancer patients. Our results shed new light on the critical role of PLK1 in reversing PARPi resistance in KRAS-amplified HGSOC, and offer a new therapeutic strategy for this class of ovarian cancer patients where only limited options currently exist.
16 October 2012 in Langenbeck's Archives of Surgery