A quantitative analytical method for valienone and its application in the evaluation of valienone production by a breakthrough microbial process / 中国天然药物

Valienone is a significant natural carbasugar member of the C7-cyclitol family as a valuable precursor for glycosidase inhibitor drugs. It is an intermediate of validamycin A biosynthesis pathway and exhibits minimal accumulation in the fermentation broth of the natural Streptomyces producer. A quantitative analytical method is crucial for the development of a breakthrough microbial process overcoming the consumption of the natural metabolic flux. The present study was designed to develop a pre-column derivatization high-performance liquid chromatography method for quantification of valienone and to help establish a straightforward fermentation process for valienone production by metabolically engineered Streptomyces hygroscopicus 5008. Valienone was derivatized by 2, 4-dinitrophenylhydrazine (DNPH) in 10 mmol·L HPO at 37 °C for 45 min and the derivatives were separated on Eclipse XDB-C (5 μm, 4.6 mm × 150 mm) column at 30 °C eluted with 50% acetonitrile for 18 min. The derivatives were detected by diode array detector at 380 nm and the configurations of the derivatives were determined by computational studies. The method was shown to be effective, sensitive, and reliable. Good linearity was found in the range of 5-2 000 μg·mL. The intra- and inter-day precisions were 1.1%-2.7% and 1.7%-2.2%, respectively. The absolute recovery of the spiked samples was 97.2%-102.6%. To date, this is the first reversed-phase high-performance liquid chromatography detection method for valienone in microbial culture medium. This method successfully helped evaluate the valienone production capability of the engineered Streptomyces hygroscopicus 5008 and could be promising for C7-cyclitol profiling of different engineered mutants combined with the metabonomics methods.

External fixation and bone grafting for collapsed and comminuted distal radius fracture / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To study the therapeutic effect of collapsed and comminuted distal radius fracture.</p><p><b>METHODS</b>Twenty-six patients with collapsed and comminuted distal radius fracture were hospitalized from July 1998 to June 2003. All fractures were treated by the methods of open reduction, sustained bone grafting and passing joint external fixator to restore the anatomic shape of distal radius.</p><p><b>RESULTS</b>All 26 cases were followed up, and the results showed that the fractures have been united radiographically. The joint surfaces were intact and there was no length discrepancy occurred in patient's radius. The average volar tilt was 6 to 15 degrees and the average ulnar tilt was 18 to 25 degrees. According to the Dieust criterion, 19 cases were rated as excellent and 7 as good.</p><p><b>CONCLUSIONS</b>The method that applying passing joint external fixator and bone grafting for the treatment of collapsed and comminuted distal radius fracture could maintain the stability of fracture and restore the length of radius and the intact of joint surface.</p>