[Practice and exploration of dynamic management of medical equipment].

Through-lifetime dynamic management, a new management model of medical equipment, is introduced in this paper. Relating to the situation of our hospital, we make a preliminary conference about theory and practice of the model from the aspects of the basement of software and hardware, primary way of practicing, and actual results.

Hepatocyte isolation from resected benign tissues: Results of a 5-year experience.

AIM: To analyze retrospectively a 5-year experience of human hepatocyte isolation from resected liver tissues with benign disease. METHODS: We established a method of modified four-step retrograde perfusion to isolate primary human hepatocytes. Samples were collected from the resected livers of patients with intrahepatic duct calculi (n = 7) and liver hemangioma (n = 17). Only the samples weighing ≥ 15 g were considered suitable for hepatocyte isolation. By using the standard trypan blue exclusion technique, hepatocyte viability and yield were immediately determined after isolation. RESULTS: Twenty-four liver specimens, weighing 15-42 g, were immediately taken from the margin of the removed samples and transferred to the laboratory for hepatocyte isolation. Warm ischemia time was 5-35 min and cold ischemia time was 15-45 min. For the 7 samples of intrahepatic duct calculi, the method resulted in a hepatocyte yield of 3.49 ± 2.31 × 10(6) hepatocytes/g liver, with 76.4% ± 10.7% viability. The 17 samples of liver hemangioma had significantly higher yield of cells (5.4 ± 1.71 × 10(6) cells/g vs 3.49 ± 2.31 × 10(6) cells/g, P < 0.05) than the samples of intrahepatic duct calculi. However, there seems to be no clear difference in cell viability (80.3% ± 9.67% vs 76.4% ± 10.7%, P > 0.05). We obtained a cell yield of 5.31 ± 1.87 × 10(6) hepatocytes/g liver when the samples weighed > 20 g. However, for the tissues weighing ≤ 20 g, a reduction in yield was found (3.08 ± 1.86 × 10(6) cells/g vs 5.31 ± 1.87 × 10(6) cells/g, P < 0.05). CONCLUSION: Benign diseased livers are valuable sources for large-number hepatocyte isolation. Our study represents the largest number of primary human hepatocytes isolated from resected specimens from patients with benign liver disease. We evaluated the effect of donor liver characteristics on cell isolation, and we found that samples of liver hemangioma can provide better results than intrahepatic duct calculi, in terms of cell yield. Furthermore, the size of the tissues can affect the outcome of hepatocyte isolation.

Reversible immortalization of human hepatocytes mediated by retroviral transfer and site-specific recombination.

AIM: To establish a method for the reversible immortalization of human hepatocytes, which may offer a good and safe source of hepatocytes for practical applications. METHODS: We successfully isolated primary human hepatocytes from surgically resected liver tissue taken from a patient with liver hemangiomas. The freshly isolated cells were then immortalized with retroviral vector SSR#69 expressing simian virus 40 large T antigen (SV40T) and hygromycin-resistance genes flanked by paired loxP recombination targets. RESULTS: The freshly isolated hepatocytes with high viability (85%) were successfully immortalized using retroviral gene transfer of SV40T. SV40T in the immortalized cells was then excised by Cre/loxP site-specific recombination. This cell population exhibited the characteristics of differentiated hepatocytes. CONCLUSION: We successfully established reversibly immortalized human hepatocytes, which will provide an unlimited supply of cells for practical applications.