Effect of three kinds of medium molecular weight proteins on the corrosion resistance of Ni-Ti and stainless steel arch wires / 口腔疾病防治

Objective @#To explore the influence and mechanism of different types of proteins on the corrosion resistance of alloy to provide a reference for the safe application and surface modification of nickel-titanium (Ni-Ti) and stainless steel bow wires in the clinic.@*Methods@#The effects of fibrinogen, IgG and mucin on the electrochemical corrosion resistance of Ni-Ti and stainless steel arch wires were tested by the potentiodynamic polarization method, and the repair ability of passive films on surfaces treated with the three proteins were tested by the cyclic polarization method. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used to determine the types of corrosion products, and the surface morphology after corrosion was analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM).@*Results @#The addition of fibrinogen, IgG or mucin to an alloy has different effects on its corrosion resistance. Adding protein can reduce the corrosion resistance of stainless steel alloys and slow the corrosion process of Ni-Ti alloys. The addition of mucin can improve the corrosion resistance of Ni-Ti alloy and the repair ability of passive film. Compared with mucin and IgG, fibrinogen can reduce the pitting resistance of Ni-Ti and stainless steel alloys.@*Conclusion @#Different types of proteins interact differently with the arch wire, form different deposition morphologies on the surface, and participate differently in the corrosion process of the alloy.

Enhancing Effect of Chiral Enhancer Linalool on Skin Permeation of Naproxen / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the permeation-enhancing effect of dl-linalool, d-linalool, and l-linalool on model drugs across excised rat skin and the effect of linalool on the ceramides in stratum corneum lipids.</p><p><b>METHODS</b>In vitro skin permeation studies were performed with Valia-Chien diffusion cells, and the permeation samples were analyzed by high performance liquid chromatography with chiral stationary phase. Infrared spectroscopy was used to investigate the effect of linalool on stratum corneum lipids.</p><p><b>RESULTS</b>When the donor vehicles added with 1% dl-linalool, 1% d-linalool, or 1% l-linalool, the steady-state skin permeation rate of naproxen was (2.47±0.63), (1.53±0.54), (1.73±0.48) μg·cm(-2)·h(-1), respectively, which is 2.49, 1.55, and 1.75 times (all P<0.05) compared with control group [(0.99±0.42)μg·cm(-2)·h(-1)], and the differences were statistically significant (all P<0.05). The permeation-enhancing effect of dl-linalool on naproxen was found significantly greater than that of d-linalool and l-linalool (both P<0.05). Compared with the control group, the stratum corneum treated with dl-linalool shifted to higher wave number on 2.09 cm(-1) of asymmetric CH2 stretching vibrations in attenuated total reflection-fourier transform infrared spectroscopy analysis. However, stratum corneum treated with d-linalool and l-linalool did not display this phenomenon.</p><p><b>CONCLUSION</b>The disturbing degree of dl-linalool on stratum corneum lipids (ceramides) is different from that of linalool enantiomers, suggesting their different enhancing effect on the same drug.</p>

The potential effects of linalool on enantioselective skin permeation of norgestrel / 药学学报

The purpose of this study is to investigate the enantioselectivity of norgestrel (NG) transdermal permeation and the potential influence of linalool and lipids on the enantioselectivity. In vitro skin permeation studies of NG across the excised rat skins were performed with Valia-Chien diffusion cells, and the permeation samples were analyzed by enantioselective HPLC. The possible enantioselective permeation of NG across intact rat back skin and lipids extracted rat back skin and the influence of linalool were evaluated. The skin permeation rate of dl-NG was two times higher than that of l-NG when donor solutions (EtOH/H2O 2 : 8, v/v) containing l-NG or dl-NG. It may be mainly attributed to the solubility discrepancy between enantiomer and racemate. The enantioselective permeation of dl-NG across intact rat skin was observed when the donor solutions containing dl-linalool. The permeation flux of l-NG was 22% higher than that of d-NG. But interestingly, the enantioselective permeation of dl-NG disappeared under the same experimental condition except that the lipid extracted rat skin was used. Attenuated total reflection-fourier transform infrared spectroscopy analysis of stratum corneum showed that the wave number for asymmetric CH2 stretching vibrations of lipids treated with dl-linalool was greater than that of the control. The results indicated that the enantioselective permeation of NG may be contributed by the interaction between dl-linalool and lipids. More than half of lipids were composed of ceramides. The stereospecific interaction maybe existed among chiral enhancer (linalool), lipids (ceramides) and/or chiral drugs (NG).

Establishment of stereospecific assay of flurbiprofen by high-performance liquid-chromatographic tandem-mass spectrometry and its application to pharmacokinetic study / 中国药学杂志

OBJECTIVE: To develop an enantioselective HPLC-MS-MS method for the pharmacokinetic study of flurbiprofen transdermal patches. METHODS: The analyte and internal standard, ketoprofen, were extracted from plasma by methyl tert-butyl ether, analyzed on a Chiralpak AD-RH column(4.0 mm×150 mm, 5 μm)with mobile phase consisting of acetonitrile-ammonium acetate buffer solution(2 mmol·L-1 pH 5.3, 50:50, V/V), and detected with UV detector at 273 nm. RESULTS: The assay was linear over the concentration range of 2.0-1000 ng·mL-1 and the intra- and inter-day precision over this range were not more than 5.8%. The limit of quantification in plasma was 2.0 ng·mL-1. CONCLUSION: The method established here is accurate, precise, rapid, sensitive, and successfully applied to the enantioselective determination of flurbiprofen in the pharmacokinetic study of flurbiprofen transdermal patches in rabbits.

Cloning, expression and functional identification of a type III polyketide synthase gene from Huperzia serrata / 药学学报

A cDNA encoding novel type III polyketide synthase (PKS) was cloned and sequenced from young leaves of Chinese club moss Huperzia serrata (Thunb.) Trev. by RT-PCR using degenerated primers based on the conserved sequences of known CHSs, and named as H. serrata PKS2. The terminal sequences of cDNA were obtained by the 3'- and 5'-RACE method. The full-length cDNA of H. serrata PKS2 contained a 1212 bp open reading frame encoding a 46.4 kDa protein with 404 amino acids. The deduced amino acid sequence of H. serrata PKS2 showed 50%-66% identities to those of other chalcone synthase super family enzymes of plant origin. The recombinant H. serrata PKS2 was functionally expressed in Escherichia coli with an additional hexahistidine tag at the N-terminus and showed unusually versatile catalytic potency to produce various aromatic tetraketides, including chalcones, benzophenones, phloroglucinols, and acridones. In particular, the enzyme accepted bulky starter substrates N-methylanthraniloyl-CoA, and carried out three condensations with malonyl-CoA to produce 1, 3-dihydroxy-N-methylacridone. Interestingly, H. serrata PKS2 lacks most of the consensus active site sequences with acridone synthase from Ruta graveolens (Rutaceae).

Deep fascia composite autologous red bone marrow transplantation for the treatment of fracture nonunion / 中国骨伤

<p><b>OBJECTIVE</b>According to bone regeneration under the membrane and the bone regeneration deep fascia composite autologous red bone marrow transplantation applied in the treatment of fracture nonunion, in order to find a simple and effective clinical treatment of nonunion.</p><p><b>METHODS</b>Since March 2006 to March 2009,17 patients of fracture nonunion were treated by the deep fascia composite autologous bone marrow transplantation,included 10 males and 7 females, aged from 7 to 52 years old (means 32 years). There were 10 cases of tibia, 5 cases of radius, 2 cases of clavicle. Injured to admission time was from 7 to 36 months (means 12 months). Ten cases underwent operation for 1 time,5 cases for twice and 2 cases for 3 times. The position of nonunion were all at bone shaft and the condition of the skin and soft tissue was good. X-ray film showed 11 cases of hyperplasia nonunion, 6 cases of shrinking. The original fixation were removed and the intramedullary nail or plate fixation were re-used, and fracture ends were sutured closed by autogenous deep fascia and implanted with autologous red bone marrow.</p><p><b>RESULTS</b>Seventeen patients were followed-up for from 5 months to 2 years with an average of 1 year. Fracture healing time was from 12 to 20 weeks (means 16 weeks). According to the criteria of fracture healing to assess efficacy, the results were excellent in 14 cases, good in 2 cases and poor in 1 case.</p><p><b>CONCLUSION</b>Deep fascia composite autologous autologous red bone marrow transplantation for the treatment of fracture nonunion is suitable at the bone shaft and good condition of skin and soft tissue. The method has been observed that the fracture healing time is short.</p>