Non-thermal atmospheric pressure dielectric barrier discharge (DBD) plasma may provide a novel approach to treat malignancies via induction of apoptosis. The purpose of this study was to evaluate the potential of DBD plasma to induce apoptosis in melanoma cells. Melanoma cells were exposed to plasma at doses that did not induce necrosis, and cell viability and apoptotic activity were evaluated by Trypan blue exclusion test, Annexin-V/PI staining, caspase-3 cleavage, and TUNEL® analysis. Trypan blue staining revealed that non-thermal plasma treatment significantly decreased the viability of cells in a dose-dependent manner 3 and 24 h after plasma treatment. Annexin-V/PI staining revealed a significant increase in apoptosis in plasma-treated cells at 24, 48, and 72 h post-treatment (p<0.001). Caspase-3 cleavage was observed 48 h post-plasma treatment at a dose of 15 J/cm2. TUNEL® analysis of plasma-treated cells demonstrated an increase in apoptosis at 48 and 72 h post-treatment (p<0.001) at a dose of 15 J/cm2. Pre-treatment with N-acetyl-L-cysteine (NAC), an intracellular reactive oxygen species (ROS) scavenger, significantly decreased apoptosis in plasma-treated cells at 5 and 15 J/cm2. Plasma treatment induces apoptosis in melanoma cells through a pathway that appears to be dependent on production of intracellular ROS. DBD plasma production of intracellular ROS leads to dose-dependent DNA damage in melanoma cells, detected by γ-H2AX, which was completely abrogated by pre-treating cells with ROS scavenger, NAC. Plasma-induced DNA damage in turn may lead to the observed plasma-induced apoptosis. Since plasma is non-thermal, it may be used to selectively treat malignancies.

No abstract

No abstract

Cold atmospheric pressure plasmas have emerged as a promising new tool for medical applications. Compared to conventional thermal plasma, such as arc coagulators and desiccators, cold plasma can be more selective in its application and may be used for effective sterilization of skin and wound tissue, wound healing and tissue regeneration, cancer treatment and blood coagulation. One of the key questions that has to be answered before these plasma technologies are introduced in medical practice is the safety of plasma treatment of living tissues, i.e. toxic dose levels of plasma exposure should be determined. It is well established that porcine (pig) skin closely resembles human skin; hence we evaluated the potential toxic effects of plasma treatment on intact and wounded skin in a Yorkshire pig model. Varying doses of Floating Electrode Dielectric Barrier Discharge (FE-DBD) and microsecond Pin-to-Hole Spark Discharge (PHD) plasmas were applied to determine a dosage regime where tissue damage occurs.

BACKGROUND The American Association for the Surgery of Trauma (AAST) patient assessment committee has created grading systems for emergency general surgery diseases to assist with clinical decision making and risk adjustment during research. Single-institution studies have validated the cholecystitis grading system as associated with patient outcomes. Our aim was to validate the grading system in a multi-institutional fashion and compare it with the Parkland grade and Tokyo Guidelines for acute cholecystitis. METHODS Patients presenting with acute cholecystitis to 1 of 8 institutions were enrolled. Discrete data to assign the AAST grade were collected. The Parkland grade was collected prospectively from the operative surgeon from four institutions. Parkland grade, Tokyo Guidelines, AAST grade, and the AAST preoperative grade (clinical and imaging subscales) were compared using linear and logistic regression to the need for surgical “bailout” (subtotal or fenestrated cholecystectomy, or cholecystostomy), conversion to open, surgical complications (bile leak, surgical site infection, bile duct injury), all complications, and operative time. RESULTS Of 861 patients, 781 underwent cholecystectomy. Mean (SD) age was 51.1 (18.6), and 62.7% were female. There were six deaths. Median AAST grade was 2 (interquartile range [IQR], 1–2), and median Parkland grade was 3 (interquartile range [IQR], 2–4). Median AAST clinical and imaging grades were 2 (IQR, 2–2) and 1 (IQR, 0–1), respectively. Higher grades were associated with longer operative times, and worse outcomes although few were significant. The Parkland grade outperformed the AAST grade based on area under the receiver operating characteristic curve. CONCLUSION The AAST cholecystitis grading schema has modest discriminatory power similar to the Tokyo Guidelines, but generally lower than the Parkland grade, and should be modified before widespread use. LEVEL OF EVIDENCE Diagnostic study, level IV.