In a prospective clinical study, we hypothesized that administration of a sub‐therapeutic dose of Ketamine (0.2 mg/kg) intraoperative would reduce the activity of TXB2 at 0 and 72 hours post surgery. Blood samples were obtained from Ketamine‐treated and untreated patients at three designated time points: before surgery, immediately (0 h) and 72 h after surgery. Purified platelets were obtained from the samples to assess TXB2 activity. The suspension of purified platelets (1e6 cells/mL) was equally divided into four treatment groups (n=3): vehicle (100 μL saline), Thrombin (2 unit/mL), Naloxone (0.1 mM), and Naloxone + Thrombin groups. Immediately following surgery both Ketamine‐treated and ‐untreated patient samples exhibited a decrease in TXB2 levels; however the Ketamine‐treated group TXB2 levels were significantly higher than the untreated group. At 72 h post‐surgery, a significant increase in concentration of TXB2 was observed. Thrombin treatment of purified platelets showed a significant increase in TXB2 levels before surgery, an effect which persisted only in the Ketamine‐treated group after surgery. The Thrombin induced increase in TXB2 levels following sub‐therapeutic dose of Ketamine was reversed by Naloxone treatment immediately after surgery, but not 72 h after surgery. The data suggests that intraoperative use of sub‐therapeutic dose of Ketamine modulates TXB2 levels in a Naloxone‐sensitive manner. (Funded by Oral Maxillofacial Surgery Foundation)
The purpose of this research is to establish an in vitro cardiac system using primary human cardiomyocyte cultures (PHCC). We hypothesized that norepinephrine (NE) and endothelin‐1 (ET‐1) will contribute to human cardiomyocyte growth. PHCC were obtained from Celprogen, San Pedro, CA and grown with varied concentrations of NE or ET‐1 for 72h. Protein expressions of contractile proteins were analyzed via Immunoblot and immunocytochemistry. Analysis of confocal images showed a significant decrease in nuclear area in all NE treatment groups. NE (10 μmol) stimulated significant increases in fluorescent intensities of the contractile proteins, f‐actin, troponin and tropomyosin. The protein expression of myosin light chain was significantly lower with increasing concentrations of NE. In addition, the average cell area increased in all groups of ET‐1. ET‐1 (1, 10, 100 nmol) exhibited a significant decrease of fluorescent intensities of f‐actin, troponin and tropomyosin. PHCC were also grown in the presence of LPS (1, 10, 100μg/ml) in a 6‐well plate for 72h. Viability data showed the cells recovered from the endotoxin treatment and maintain steady growth in each concentration of LPS. In contrast to NE, ET‐1 exhibited a decrease on the expression of contractile proteins in PHCC.
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