Neutral red (NR) in medium was absorbed and concentrated in lysosomes of cultured rat and human hepatocytes. NR uptake increased with the time of incubation and reached a plateau in 2 hr. Uptake was proportional to the concentration of the NR solution and the numbers of viable liver cells. Prolonged culture of hepatocytes increased the numbers of lysosomes, and thus, the dye accumulation. The NR can be extracted from lysosomes for quantitative measurement of hepatocyte viability and cytotoxicity of xenobiotics. With this assay, several serum-free media (e.g., Waymouth's, MEM, LHC-8, etc.) were compared for the maintenance of viable hepatocytes in vitro. Interestingly, LHC-8 medium, which is used to grow human bronchial epithelial cells, best preserved viable rat hepatocytes. The cytotoxic effects of dimethylnitrosamine (DMN) and aflatoxin B1 (AFB1) were examined by NR assay on rat and human hepatocyte cultures and were found to be dependent on dose and time of the exposures. NR50 was 20 mM for DMN and 0.072 microM for AFB1 in rat hepatocytes with 24 hr of exposures and reduced to 12.5 mM for DMN and 0.053 mu microM for AFB1 with 48 hr exposures. Human hepatocytes were more resistant to the toxicity of both chemicals; NR50 values were 100 mM DMN and 1.8 microM AFB1 respectively, for 24 hr treatments. Compared with lactate dehydrogenase (LDH) leakage test, the NR assay was simpler and more sensitive in determining the viability and cytotoxicity of xenobiotics in primary cultures of hepatocytes.

These results argue for the feasibility of intracavitary DCC-E1A administration, provide a clear proof of preclinical concept, and warrant phase II trials to determine the antitumor activity of the E1A gene.

Introduction Sunitinib is an approved treatment for metastatic renal cell carcinoma (RCC). A prospective clinical trial was conducted to evaluate the safety and clinical response to sunitinib administered prior to nephrectomy in patients with localized or metastatic clear cell RCC. Methods Patients with biopsy-proven clear cell RCC were enrolled and treated with sunitinib malate, 37.5 mg daily, for 3 months prior to nephrectomy. The primary endpoints was safety. Results Twenty patients were enrolled during an 18 month period. The most common toxicities were GI symptoms and hematologic. Grade 3 toxicities occurred in 6 patients (30%). No surgical complications were attributable to treatment with sunitinib. Seventeen of the 20 patients (85%) experienced a decrease in tumor diameter (mean change −11.8%, range −27% to 11%) and cross-sectional area (mean change −27.9%, range −43% to 23%). Enhancement on contrast-enhanced CT decreased in 15 patients, with a mean change in Hounsfield units of −22% (range −74% to 29%). Following a decrease in tumor size, 8 patients with cT1b tumors underwent laparoscopic partial nephrectomy. Surgical parameters such as blood loss, transfusion rate, operative time, and complications were similar to those who underwent surgery during the study period and were not enrolled on the trial. Conclusions Preoperative treatment with sunitinib is safe. Sunitinib decreased the size of primary RCC in 17 of 20 patients, and future trials can be considered to evaluate the use of neoadjuvant sunitinib to maximize nephron-sparing and decrease recurrence risk for high-risk, localized RCC.

Despite its expression in a small subset of malignancies of epithelial origin, Pax-5 is still a good and reliable immunomarker in diagnosing B-NHL, HL and neuroendocrine carcinomas.