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Arginine is a dibasic, cationic, semiessential amino acid with numerous roles in cellular metabolism. It serves as an intermediate in the urea cycle and as a precursor for protein, polyamine, creatine and nitric oxide (NO) biosynthesis. Arginine is conditionally essential since it becomes necessary under periods of growth and after recovery after injury. Arginine also promotes wound healing and functions as a secretagogue stimulating the release of growth hormone, insulin-like growth factor 1, insulin, and prolactin. Furthermore, arginine has several immunomodulatory effects such as stimulating T- and natural killer cell activity and influencing pro-inflammatory cytokine levels. The discover that l-arginine is the sole precursor for the multifunctional messenger molecule nitric oxide (NO) led to investigation into the role of arginine in numerous physiologic and pathophysiologic phenomena including cancer. Although NO was first identified in endothelial cells, it is now recognized to be generated by a variety of cell types, including several tumor cell lines and solid human tumors. Unfortunately, the precise role of NO in cancer is poorly understood but it may influence tumor initiation, promotion, and progression, tumor-cell adhesion, apoptosis angiogenesis, differentiation, chemosensitivity, radiosensitivity, and tumor-induced immunosuppression. The biological effects of NO are complex and dependent upon numerous regulatory factors. Further research is necessary to enhance our understanding of the complex mechanisms that regulate NO's role in tumor biology. A better understanding of the role of arginine-derived NO in cancer may lead to novel antineoplastic and chemopreventative strategies.

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Compared with the surgery-alone series, adjuvant RT appears to improve the probability of local control. Preoperative RT may be the preferred sequence potentially to improve tumor resectability and local-regional control with less risk of complications than with postoperative RT.

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Any new tool introduced for education needs to be validated. We developed a virtual human experience called the Virtual Objective Structured Clinical Examination (VOSCE). In the VOSCE, a medical student examines a life-size virtual human who is presenting symptoms of an illness. The student is then graded on interview skills. As part of a medical school class requirement, thirty three second year medical students participated in a user study designed to determine the validity of the VOSCE for testing interview skills. In the study, participant performance in the VOSCE is compared to participant performance in the OSCE, an interview with a trained actor. There was a significant correlation (r(33)=.49, p<.005) between overall score in the VOSCE and overall score in the OSCE. This means that the interaction skills used with a virtual human translate to the interaction skills used with a real human. Comparing the experience of virtual human interaction to real human interaction is the critical validation step towards using virtual humans for interpersonal skills education.