[Establishment of mouse model of bone metastasis of prostate cancer and breast cancer via femoral artery injection of tumor cells].

OBJECTIVE: To explore an efficient and reliable method for establishing an animal model of bone metastasis of tumors. METHODS: Male C57BL/6J mice were randomized into 4 equal groups to receive injections of normal saline or prostate cancer RM-1 cell suspension via the femoral artery or the external iliac artery, and breast cancer 4T1-luc cells were injected in 15 female BALB/c mice via the femoral artery. The operation time, postoperative survival rate, and the tumor formation rates in the mice with two different injection methods were compared. The tumor metastasis in the mice was evaluated with in vivo imaging. RESULTS: The mean time for hemostasis time was 2.53∓1.75 min in mice receiving tumor cell injection via the femoral artery, significantly shorter than that in mice with injections via the external iliac artery (4.70∓1.63 min; P<0.05); the mean operation time was 14.67∓2.16 min and 22.47∓3.50 min in the two groups, respectively (P<0.05). At 21 days after the operation, the survival rate was 93.3% in femoral artery injection group, significantly higher than that in external iliac artery injection group (66.7%;P<0.05). The tumor metastasis rate was 100% in both groups. CONCLUSION: Injection of the tumor cells via the femoral artery is more suitable for establishing mouse models of bone metastasis of cancers.

A novel technique of semi-aerobic aged refuse biofilter for leachate treatment.

We developed a semi-aerobic aged refuse biofilter (SAARB) for leachate treatment and examined its advantages and disadvantages compared to previous aged refuse biofilters (ARBs). To assess its treatment capability, decontamination mechanisms and optimal performance parameters, a single-period experiment and L(9)(3(4)) orthogonal array design experiments were conducted on artificial leachate. The SAARB markedly enhanced the treatment capability and removal efficiency of organic matter and nitrogen pollutants due to the alternating aerobic-anoxic-anaerobic zones in situ. The reduction in chemical oxygen demand (COD), ammonia nitrogen (NH(4)(+)-N) and total nitrogen (TN) exceeded 98%, 94%, and 80%, respectively. After the leachate was distributed onto the SAARB surface, the effluent velocity decreased as a logarithmic function, and there was a concomitant reduction in leachate effluent volume. Based on the capacity for removal of COD, NH(4)(+)-N, and TN, the effective height of aged refuse in a SAARB was enough to be 900mm. An excellent treatment efficiency could be achieved at 20-35°C, with a leachate distribution time of 1h once every period of 2-3 days, hydraulic loading of 11-30L/(m(3)day), and COD loading of 550-1200g/(m(3)day). This new SAARB system demonstrates superior efficacy for biofilter compared to other ARB systems, especially for nitrogen removal from leachate.