Study on the proportion & mechanism of reliving asthma of drug partnership comprising herbal Ephedrae sinica & Pheretima aspergilum / 中国中药杂志

<p><b>OBJECTIVE</b>To study the proportion and mechanism of relieving asthma of drug partnership comprising herbal Ephedrae & Pheretima.</p><p><b>METHOD</b>To study relaxant effect on 10 micromol x L(-1) carbachol (CCh) and 10 micromol x L(-1) histamine (His) precontracted isolated tracheal rings and lowering effect on short-circuit current (Isc) increase induced by 10 micromol x L(-1) CCh with 3 proportions of 1:1, 1:3, 1:9 extract.</p><p><b>RESULT</b>1:3 proportions dose-dependently relaxed CCh-precontracted isolated tracheal rings, IC50 of 1:1, 1:3 is 7.5, 15 mg x mL(-1) respectively, 1:9 could not produce 50% inhibition effect on CCh-evoked contraction; 3 proportions also dose-dependently relaxed His-precontracted isolated tracheal rings, IC50 of 1:9, 1:3 and 1:1 is 0.19, 0.61, 1.8 mg x mL(-1) respectively. On the other hand,the orders potency of the decrease effect on CCh-evoked short circuit current increase is 1:3 > 1:1 > 1:9. The difference is not significant (P < 0.05).</p><p><b>CONCLUSION</b>Herbal Ephedrae & Pheretima had tracheal muscle relaxant and epithelium ion secretion inhibition effect, its mechanism of relieving asthma involved anti-CCh and anti-His effect 1:3 was the most appropriate dosage ratio in the anti-asthmatic drug partnership.</p>

Adventitious root induction and in vitro culture of Panax notoginseng / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate the induction and culture of adventitious root of Panax notoginseng.</p><p><b>METHOD</b>Three ways, induction from the explants of three-year-old P. notoginseng. The explants of regenerated shoots and calluses, were used to induce adventitious roots. The effects of 2, 4-dichlorophenoxyacetic acid, indole-3-butyric acid and naphthylacetic acid on adventitious root induction were investigated respectively. The effects of four modes of separating adventitious roots from the parent tissues on culture in vitro were compared.</p><p><b>RESULT</b>Adventitious roots were successfully induced by three methods, of which the young flower bud callus was the best material for the induction of adventitious root. Indole-3-butyric acid possessed the strongest potency for induction. The liquid culture system was established by continuous culture of adventitious roots together with their parent tissues before separated.</p><p><b>CONCLUSION</b>The acquisition and culture in vitro in liquid culture system of adventitious roots of P. notoginseng lay a foundation for the next investigation.</p>

A single tetracycline-regulated vector devised for controlled insulin gene expression / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To construct a single plasmid vector mediating doxycycline-inducible recombined human insulin gene expression in myotube cell line.</p><p><b>METHODS</b>An expression cassette of rtTAnls driven by promoter of human cytomegalovirus and a furin-cuttable recombined human insulin expression cassette driven by a reverse poly-tetO DNA motif were cloned into a single plasmid vector (prTR-tetO-mINS). The prTR-tetO-mINS and pLNCX were co-transfected into a myotube cell line (C2C12) and pLNCX vector were used as a control. After selection with G418, the transfected cells were induced with doxycycline at concentrations of 0, 2, and 10 microg/mL. RT-PCR was used to determine expression levels of recombinant insulin mRNA at the 5th day. Insulin production in cell cultures medium (at different incubation time) and cell extracts (at the 7th day) were analyzed with human pro/insulin RIA kits.</p><p><b>RESULTS</b>Immune reactive insulin (IRI) level in cell medium was found increased at 24 hours of doxycycline incubation, and still increased at the 5th day. After withdrawn of doxycycline, IRI decreased sharply and was at baseline three days later. IRI and human insulin mRNA levels were positively related to different levels of doxycycline. A 25-fold increase in IRI was found against background expression at the 7th day.</p><p><b>CONCLUSION</b>Human insulin expression can be successfully regulated by doxycycline and the background was very low. This single tet-on insulin expression system may provide a new approach to a controlled insulin gene therapy in skeletal muscle.</p>