Radiosynthesis, radiochemical, and biological characterization of 177 Lu-labeled diethylenetriamine penta-acetic acid.

Diethylenetriamine penta-acetic acid (DTPA), when complexed with a gamma (γ)-emitter radioisotope like 99m Tc, is used for renal function diagnosis and many other diagnostic applications. The main aim of this study was to develop a novel and versatile single-step methodology for the synthesis of a new 177 Lu-labeled radiopharmaceutical with high radiochemical yield, which can be used for diagnostic purposes and therapeutic purposes also. The single and well-defined 177 Lu-DTPA complex was radiochemically characterized by paper chromatography, thin-layer chromatography, high-performance liquid chromatography, and electrophoresis techniques. Dependence of the labeling yield of 177 Lu-DTPA complex on different factors was studied in detail. Biological evaluation was also performed in a normal rabbit by developing images under a γ camera at various time intervals. More than 99% labeling yield was obtained by reacting DTPA with 177 Lu at specific conditions (pH 7.0, 15 minutes reaction time at 100 °C). 177 Lu-DTPA complex showed high stability both at room temperature and in vitro. Biodistribution studies in normal mice indicated the fractional renal uptake of intravenously administered 177 Lu-DTPA complex, which reached in the kidneys within 2-3 minutes. Scintigraphy showed rapid clearance from the body. Based on these results, we propose that 177 Lu-DTPA complex might be used as an ideal candidate for functional evaluation of kidneys and the urinary tract, especially when needed to be transported to long-range consumer sites, because of its suitable half-life.

Optimization of saccharification potential of recombinant xylanase from Bacillus licheniformis.

Saccharification potential of xylanase enzyme cloned from Bacillus licheniformis into E. coli BL21 (DE3) was evaluated against plant biomass for the production of bioethanol. The expression of cloned gene was studied and conditions were optimized for its large scale production. The parameters effecting enzyme production were examined in a fermenter. Recombinant xylanase has the ability to breakdown birchwood xylan to release xylose as well as the potential to treat plant biomass, such as wheat straw, rice straw, and sugarcane bagass. The saccharification ability of this enzyme was optimized by studying various parameters. The maximum saccharification percentage (84%) was achieved when 20 units of recombinant xylanase were used with 8% sugarcane bagass at 50°C and 120 rpm after 6 hours of incubation. The results indicated that the bioconversion of natural biomass by recombinant xylanase into simple sugars can be used for biofuel (bioethanol) production. This process can replace the use of fossil fuels, and the use of bioethanol can significantly reduce the emission of toxic gases. Future directions regarding pre-treatment of cellulosic and hemicellulosic biomass and other processes that can reduce the cost and enhance the yield of biofuels are briefly discussed.