Numerical Simulation of Temperature Variations during the Application of Safety Protocols in Magnetic Particle Hyperthermia.

Unavoidably, magnetic particle hyperthermia is limited by the unwanted heating of the neighboring healthy tissues, due to the generation of eddy currents. Eddy currents naturally occur, due to the applied alternating magnetic field, which is used to excite the nanoparticles in the tumor and, therefore, restrict treatment efficiency in clinical application. In this work, we present two simply applicable methods for reducing the heating of healthy tissues by simultaneously keeping the heating of cancer tissue, due to magnetic nanoparticles, at an adequate level. The first method involves moving the induction coil relative to the phantom tissue during the exposure. More specifically, the coil is moving symmetrically-left and right relative to the specimen-in a bidirectional fashion. In this case, the impact of the maximum distance (2-8 cm) between the coil and the phantom is investigated. In the second method, the magnetic field is applied intermittently (in an ON/OFF pulsed mode), instead of the continuous field mode usually employed. The parameters of the intermittent field mode, such as the time intervals (ON time and OFF time) and field amplitude, are optimized based on the numerical assessment of temperature increase in healthy tissue and cancer tissue phantoms. Different ON and OFF times were tested in the range of 25-100 s and 50-200 s, respectively, and under variable field amplitudes (45-70 mT). In all the protocols studied here, the main goal is to generate inside the cancer tissue phantom the maximum temperature increase, possible (preferably within the magnetic hyperthermia window of 4-8 °C), while restricting the temperature increase in the healthy tissue phantom to below 4 °C, signifying eddy current mitigation.

Prospective study comparing the bladeless optical access trocar versus Hasson open trocar for the establishment of pneumoperitoneum in laparoscopic renal procedures.

INTRODUCTION: To present a single centre prospective randomized study on the use of the bladeless Optiview system (Ethicon Endosurgery, Cincinnati, OH) to create the pneumoperitoneum in laparoscopic renal procedures reporting the results with regards safety, efficacy and complications and comparing it with the Hasson open technique. PATIENTS AND METHODS: Sixty patients were randomly recruited, 27 to the open and 33 to the bladeless group at the Bristol Urological Institute, UK. Time to insertion, time to closure and any intraoperative and postoperative complication related to trocar insertion was recorded. RESULTS: All procedures were performed for renal pathology. BMI values were similar in both groups. The mean time to insertion of the 12 mm Hasson and Bladeless trocars were 443 and 125 seconds, respectively (p < 0.0001). The incision in the bladeless group was only closed when the defect exceeded 12 mm (38%) or extended for specimen removal (23%), resulting in a mean time to closure of 203 seconds. In the Hasson group, entry into the abdominal cavity could not be confirmed in two patients (7.4%) due to multiple adhesions. In the Bladeless group, there was one failed placement (3%) requiring conversion to the Hasson technique and two injuries to intraabdominal structures (peritoneal minor bruising, liver injury requiring conversion to open procedure, 6%), There was one incidence of gas leakage (3%). There were no reports of port site herniation at a mean follow up of 9 months. CONCLUSION: Direct placement of a bladeless trocar under direct vision in a desufflated abdomen can reduce port placement time when compared to the Hasson technique. The benefits are maximised by using the bladeless trocar for procedures not requiring intact specimen removal. However, despite visualisation of tissue layers, this port cannot prevent serious intra abdominal injuries that can occur in a higher percentage of cases in comparison to the Hasson technique.

Nuclear expression of hypoxia-inducible factor-1alpha in clear cell renal cell carcinoma is involved in tumor progression.

OBJECTIVES: The most frequent genomic abnormality in clear cell renal cell carcinoma (cc-RCC) is inactivation of Von Hippel-Lindau gene (VHL). pVHL19 is a ligase promoting proteosomal degradation of hypoxia-inducible factor-1alpha (HIF-1alpha); pVHL30 is associated with microtubules. VHL exert its oncogenetic action both directly and through HIF-1alpha activation. TNM classification is unable to define a correct prognostic evaluation of intracapsular cc-RCC. The nucleo-cytoplasmic trafficking in VHL/HIF-1alpha pathway could be relevant in understanding the molecular pathogenesis of renal carcinogenesis. This study analyzes VHL/HIF-1alpha proteins in a large series of intracapsular cc-RCCs, correlating their expression and cellular localization with prognosis. MATERIALS AND METHODS: Two anti-pVHL (clones Ig32 and Ig33) and 1 anti-HIF-1alpha were used on tissue microarrays from 136 intracapsular cc-RCCs (mean follow-up: 74 mo). Clone 32 recognizes both pVHLs, whereas clone 33 only pVHL30. Results were matched with clinicopathologic variables and tumor-specific survival (TSS). RESULTS: A strong cytoplasmic positivity was found for all antibodies in the largest part of cases, associated to a strong nuclear localization in the case of HIF-1alpha. All pVHL-negative cases were associated with high HIF-1alpha expression. pVHL negativity and HIF-1alpha nuclear positivity significantly correlated with shorter TSS. In multivariate analysis both pVHL negativity and HIF-1alpha nuclear expression were independent predictors of TSS. CONCLUSIONS: The localization of the proteins well matches with their role and with the supposed tumor molecular pathways. The correlation with prognosis of VHL/HIF-1alpha alterations confirms the relevance of their molecular pathway and of the cellular trafficking of their products in the pathogenesis of renal cancer.