Effects of biochars derived from chicken manure and rape straw on speciation and phytoavailability of Cd to maize in artificially contaminated loess soil.

While biochar can reduce the bioavailability of heavy metals in acidic soils and reduce their risk of entering the food chain, conditions for alkaline soils such as loess soils with high pH values, high carbonate content and low organic matter content remain unclear. Pot experiments were conducted to assess the effects of four rates (1%, 5%, 10%, and 15% w/w) of biochars prepared at 600 °C from chicken manure and rape straw (CBC and RBC) on soil properties, Cd speciation and phytoavailability, and plant growth in Cd contaminated (20 mg kg-1) light sierozem using maize (Zea mays L.) as an indicator plant. Biochar additions significantly (P < 0.05) increased soil pH values, cation exchange capacity (CEC) and soil organic matter (OM). The results showed that Cd speciation turned somewhat into stable state as biochar application increased. When CBC and RBC was applied at the rate of 15%, the content of acid-extractable Cd decreased only by 16.3% and 11.64%, respectively. The uptake of Cd by maize shoots scarcely decreased with CBC and RBC amendment at the rate of 1% and 5%, respectively. Although it seemed that additions of more than 5% CBC or RBC significantly (P < 0.05) reduced Cd contents in maize shoots, maize growth was largely inhibited due to the high value of soil pH. These results could provide different implications for immobilization remediation of loess soils (e.g., light sierozem) contaminated with Cd.

Biodistribution of etoposide via intratumoral chemotherapy with etoposide-loaded implants.

Etoposide (VP16) is the traditional antitumor agent which has been widely used in a variety of cancers. However, intravenous administration of VP16 was limited in clinical application because of its low aqueous solubility, poor bioavailability and dose-limiting adverse effects. Local chemotherapy with VP16-loaded drug delivery systems could provide a continuous release of drug at the target site, while minimizing the systemic toxicity. In this study, we prepared the poly-l-lactic acid (PLLA) based VP16-loaded implants (VP16 implants) by the direct compression method. The VP16 implants were characterized with regards to drug content, micromorphology, drug release profiles, differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) analyses. Furthermore, the biodistribution of VP16 via intratumoral chemotherapy with VP16 implants was investigated using the murine Lewis lung carcinoma model. Our results showed that VP16 dispersed homogenously in the polymeric matrix. Both in vitro and in vivo drug release profiles of the implants were characterized by high initial burst release followed by sustained release of VP16. The VP16 implants showed good compatibility between VP16 and the excipients. Intratumoral chemotherapy with VP16 implants resulted in significantly higher concentration and longer duration of VP16 in tumor tissues compared with single intraperitoneal injection of VP16 solution. Moreover, we found the low level of VP16 in plasma and normal organ tissues. These results suggested that intratumoral chemotherapy with VP16 implants enabled high drug concentration at the target site and has the potential to be used as a novel method to treat cancer.