Two-Step Purification of L-Asparaginase from Acrylaway® L

Abstract L-Asparaginase (L-ASNase) is a biopharmaceutical used for acute lymphoblastic leukaemia (ALL) treatment, dramatically increasing the patients' chance of cure. However, its production and distribution in developing countries were disrupted because of its low profitability, which caused great concern among patients. This study evaluates the feasibility of combining fractional precipitation and aqueous two-phase systems (ATPS) to purify L-ASNase from a low-grade product, commercially known as Acrylaway® L. The ATPS purification results were not particularly expressive compared to the two-step purification process composed of ethanol precipitation and gel filtration, which was able to recover the target molecule with a purification factor over 5 fold. Thus, we studied a purification process capable of manufacturing pharmaceutical grade L-ASNase from a commercially available low-grade raw material; however, improvements regarding its throughput must be achieved, and high purity is the first step to apply it as a new biopharmaceutical product. The proposed process could pose as a short-time solution to mitigate its shortage while a cost-effective production plant is being developed.

Optimization of parameters for preparation of docetaxel-loaded PLGA nanoparticles by nanoprecipitation method / 华中科技大学学报（医学）（英德文版）

The purpose of this study was to develop docetaxel-poly (lactide-co-glycolide) (PLGA) loaded nanoparticles by using nanoprecipitation method and optimize the relative parameters to obtain nanoparticles with higher encapsulation efficiency and smaller size. The physicochemical characteristics of nanoparticles were studied. The optimized parameters were as follows: the oil phase was mixture of acetone and ethanol, concentration of tocopheryl polyethylene glycol succinate (TPGS) was 0.2%, the ratio of oil phase to water phase was 1:5, and the theoretical drug concentration was 5%. The optimized nanoparticles were spherical with size between 130 and 150 nm. The encapsulation efficiency was (40.83±2.1)%. The in vitro release exhibited biphasic pattern. The results indicate that docetaxel-PLGA nanoparticles were successfully fabricated and may be used as the novel vehicles for docetaxel, which would replace Taxotere® and play great roles in future.

Study on concentration of nuorovirus genegroup II from environmental water / 病毒学报

A new viral sampling concentration device was designed which was equipped with a new cationic filter membrane-Nanoceram suitable for field sampling. Norovirus Genegroup II was detected from environmental water with the aid of this device. The effects on virus recovery of prefiltration, various second-concentration methods, and different eluants were investigated through pre-experiment. The concentration optimized process, and the optimal concentration process were then determined. The results showed that the prefiltration had a profound effect on virus recovery, and two second-concentration method: PEG-NaC1 precipitation and celite adsorption, had almost the same concentration effects. The Na2 HPO4 solution of 0.15 mol/L was selected as the final eluant to elute the adsorbed Nuorovirus from the celite. The virus recovery of Nanoceram was determined to be 3.02%. Finally, successful detection of Norovirus GII in sewage from Yangqiao River, Fengtai District, Beijing was acheived. All these data had shown that the Naneceram filter concentration method could concentrate Norovirus from environmental water with a steady effects.

Recovery of silver residues from dental amalgam

Dental amalgam residues are probably the most important chemical residues generated from clinical dental practice because of the presence of heavy metals among its constituents, mainly mercury and silver. OBJECTIVE: The purpose of this study was to develop an alternative method for the recovery of silver residues from dental amalgam. MATERIAL AND METHODS: The residue generated after vacuum distillation of dental amalgam for the separation of mercury was initially diluted with 32.5 percent HNO3, followed by precipitation with 20 percent NaCl. Sequentially, under constant heating and agitation with NaOH and sucrose, the sample was reduced to metallic silver. However, the processing time was too long, which turned this procedure not viable. In another sequence of experiments, the dilution was accomplished with concentrated HNO3 at 90ºC, followed by precipitation with 20 percent NaCl. After washing, the pellet was diluted with concentrated NH4OH, water and more NaCl in order to facilitate the reaction with the reducer. RESULTS: Ascorbic acid was efficiently used as reducer, allowing a fast reduction, thus making the procedure viable. CONCLUSIONS: The proposed methodology is of easy application and does not require sophisticated equipment or expensive reagents.

Preliminary study to investigate dynamic extract process of Huanglian Jiedu Tang and the mechanism of subsidence produce / 中国中药杂志

<p><b>OBJECTIVE</b>To study the phenomenon of subsidence emergence in the process of Huanglian Jiedu Tang decoction extraction, and the mechanism of subsidence emergence.</p><p><b>METHOD</b>UV was applied to determine the concentration of total alkaloids and total flavones; Simultaneous determination of berberine, jatrorrhizine, palmatine, baicalin and geniposide were carried out by HPLC; The solid holdup and precipitation rate were calculated by the formula. The relativity among these parameters was analyzed by the SPSS software program.</p><p><b>RESULT</b>The contains of berberine, jatrorrhizine, palmatine in total alkaloids showed a good correlation with total alkaloids. The correlation between baicalin and total flavones was lower than that between geniposide and total flavones. Compared to precipitation rate, solided hold up shows a larger relevance with index component</p><p><b>CONCLUSION</b>With the change of time, the total alkaloids represented by berberine alkaloids and baicalin at a certain concentration can be regarded as the equilibrium point, or one generated by the critical point of precipitation, the reaction can generate "sediments"; because "precipitation objects" generated, reducing the concentration of the above-mentioned components, destroy the" balance". The relevant components of herbal medicine increased dissolution rate, at the same time might partly dissolved sediment, reaching a new equilibrium state.</p>

Purification and characterizaton of plastidic pyruvate kinase from developing seeds of Brassica campestris L.

Plastidic pyruvate kinase (ATP: pyruvate phosphotransferase, EC 2.7.1.40) was purified to near homogeneity as judged by native PAGE with about 4% recovery from developing seeds of Brassica campestris using (NH4)2SO4 fractionation, DEAE-cellulose chromatography, gel filtration through Sepharose-CL-6B and affinity chromatography through reactive blue Sepharose-CL-6B. The purified enzyme having molecular mass of about 266 kDa was quite stable and showed a broad pH optimum between pH 6.8-7.8. Typical Michaelis-Menten kinetics was obtained for both the substrates with K(m) values of 0.13 and 0.14 mM for PEP and ADP, respectively. The enzyme could also utilize CDP, GDP or UDP as alternative nucleotide to ADP, but with lower Vmax and higher K(m). The enzyme had an absolute requirement for a divalent and a monovalent cation for activity and was inhibited by oxalate, fumarate, citrate, isocitrate and ATP, and activated by AMP, aspartate, 3-PGA, tryptophan and inorganic phosphate. ATP inhibited the enzyme competitively with respect to PEP and non-competitively with respect to ADP. Similarly, oxalate inhibition was also of competitive type with respect to PEP and non-competitive with respect to ADP. This inhibition by either ATP or oxalate was not due to chelation of Mg2+, as the inhibition was not relieved on increasing Mg2+ concentration even upto 30 mM. Initial velocity and product inhibition studies demonstrated the reaction mechanism to be compulsory ordered type. The enzyme seems to be regulated synergistically by ATP and citrate.

Modified Levinson's test in rapid diagnosis of tuberculous meningitis.

Modified Levinson's precipitation test was done in 64 cases of TBM, 54 cases of TBM with inconsistent CSF finding, and 32 cases of pyogenic meningitis. The test was positive in 93.7% cases of TBM (sensitivity, 93.7%), 85.5% cases of TBM with doubtful diagnosis and in 9.4% cases of pyogenic meningitis (specificity 90.6%) compared to 79.7%, 72.2% and 18.8% in original Levinson's test, respectively. With CSF examination only 66% cases of TBM could be diagnosed while with modified Levinson's test and CSF analysis 89% cases could be diagnosed (p < 0.001). So modified Levinson's test for diagnosis of TBM is better than Levinson's test (p < 0.05) with an added advantage of time saving.