Development of a Microbe-Zeolite Carrier for the Effective Elimination of Heavy Metals from Seawater.

The purpose of this study was to investigate the potential of zeolite-supported sulfatereducing bacteria (SRB) in enhancing the removal of Cu(2+), Ni(2+), and Cr(6+) in contaminated seawater. Our results show that SRB-immobilized zeolite carriers can enhance the removal of heavy metals. In addition, heavy metals were generally better removed at conditions of 37°C. Cu(2+), Ni(2+), and Cr(6+) were effectively removed by 98.2%, 90.1%, and 99.8% at 100 parts per million concentration of the heavy metals, respectively. These results indicate that SRB-zeolite carriers hold great potential for use in the removal of cationic heavy metal species from marine environment.

A duplex oligodeoxynucleotide-dendrimer bioconjugate as a novel delivery vehicle for doxorubicin in in vivo cancer therapy.

We designed a bioconjugate between duplex oligodeoxynucleotides (dODNs) and a dendrimer (DEN) and demonstrate its feasibility as a novel delivery system for doxorubicin (Dox) in animal tumor models and against cancer cells in vitro. The dODNs-DEN conjugates formed stable complexes with Dox (~184 Dox molecules per conjugate) and the resulting Dox-loaded conjugate exhibited a sustained drug release pattern both in vitro and in vivo. Pharmacokinetic studies showed that Dox-loaded dODNs-DEN conjugates were cleared from plasma much more slowly (up to 5.3h) than was free Dox (0.65h). Furthermore, tumors retained a higher amount of Dox in mice treated with the conjugate group compared to that of free Dox-treated group at the same dosage. In mice bearing 4T1 murine breast tumor allografts, the dendrimer conjugate, at a Dox concentration of 1mg/kg, was more effective than the equivalent concentration of free Dox and tumor size reduction was equivalent to that seen using 4mg/kg free Dox. We observed no severe systemic toxicity or cardiotoxicity in mice treated with the conjugate, as indicated by body weight change and heart tissue histology. These findings indicate that dODNs-DEN conjugates can be used to administer Dox with improved pharmacokinetics, lower toxicity, and an increased ability to concentrate drugs in tumors, compared with free drug, and that such conjugates are effective against tumors in vivo.

[Role of prostaglandins in colon cancer].

Colon cancer is one of the major leading causes of cancer-related deaths in the Western countries. In Korea, the incidence of colon cancer is increasing due to changes in environment and lifestyle such as diet. Chemoprevention strategy using non-steroidal anti-inflammatory drugs (NSAIDs) has been under intensive clinical and epidemiological research as these drugs suppress colorectal cancer. The best known targets of NSAIDs are cyclooxygenase (COX) enzymes, which convert arachidonic acid to prostaglandins (PGs) and thromboxane. Among these PGs, prostaglandin E2 (PGE2) can promote tumor growth by binding its receptors and activating signal pathways which control cell proliferation, migration, apoptosis, and angiogenesis. Therefore, COX inhibition is promising approach for chemoprevention of colorectal cancer. However, the prolonged use of COX-2 inhibitors is associated with unacceptable cardiovascular side effects. Thus, new targets involved in PGs metabolism are under investigation. 15-hydroxyprostaglandin dehydrogenase (15-PGDH), a key metabolic enzyme of PGE2, was up-regulated in normal colonic epithelium, but decreased in colon cancer. Recent findings suggest that 15-PGDH is involved in the neoplastic progression of initiated colonic epithelial cells. Also, new players related with PGs metabolism including prostaglandin transporter (PGT) and microsomal prostaglandin E synthase (mPGES) were reported to play a role in colorectal cancer development. This review presents current knowledge about the role of prostaglandins and associated proteins in colorectal cancer development and progression.