Simultaneous determination of 18 different amino acids in in vitro fertiIization medium by ultra-high performance liquid chromatography-tandem mass-spectrometry / 中国组织工程研究

BACKGROUND: At present, in the quality control file or technical standards of in vitro fertilization medium, indicators for component contents and detection methods have not yet been defined. To ensure the safety and effectiveness of these products, we should try to establish and improve the quality standards. OBJECTIVE: To establish a method for simultaneously testing 18 kinds of amino acids by ultra-high performance liquid chromatography-tandem mass-spectrometry (UHPLC-MSMS), and to analyze the difference in the content of different amino acids in the medium for different uses. METHODS: Using the UHPLC-MSMS, we detected the indicator components of 18 different amino acids in the in vitro fertilization medium. These amino acids included glycine, leucine, methionine, tyrosine, histidine, threonine, alanine, isoleucine, tryptophan, cystine, lysine, aspartic acid, valine, phenylalanine, valine, serine, glutamic acid, arginine. The UHPLC separation was performed on a SUPELCO Discovery HS F5-3 column (15 cm×2.1 mm, 3 μm) in a gradient elute mode with acetonitrile and water (both containing 0.1% formic acid) as the mobile phase at a flow rate of 0.35 mL/min. The column temperature was 40 ℃. MS detection was performed with multiple-reaction monitoring mode using negative electro spray ionization. RESULTS AND CONCLUSION: The linearity was achieved in the range of 0.25-12.5 mmol/L for the 18 different amino acids. The average recovery rate of these amino acids ranged 86.3% to 125.3%. The relative standard deviation of the precision experiment and the repeatability experiment was less than 4.7%. These findings indicate that this is a sensitive, rapid, accurate, and specific method that can be used for the quality control of in vitro fertilization medium.

Detection of residual diphenylmethane diisocyanate monomer in a hemodialysis catheter / 中国组织工程研究

BACKGROUND:In the current quality control file or technical standards of the hemodialysis catheter,the indicators of the component contents and detection methods of the residual diphenylmethane diisocyanate (MDI) monomer are undefined.To ensure the safety and effectiveness of these products,we should try to establish and improve the quality standards.OBJECTIVE:To establish a method for determination of the residual MDI monomer in a hemodialysis catheter by gas chromatography (GC),and to analyze the bio-security of the MDI.METHODS:Samples collected in the hemodialysis catheter were heated to reflux with ethyl acetate and the residual MDI content was analyzed by the GC.The GC separation was performed on a DB-5 MS column (30 mx0.25 mm),the temperature of which rose by program.The initial temperature was 60 ℃,maintained for 5 minutes,rose to 280 ℃ with a rate of 15 ℃/min,and maintained for 6 minutes.The temperature of the Injector and FID detector was both 280 ℃.Carrier gas was 99.999％ nitrogen.RESULTS AND CONCLUSION:The linearity was achieved in the range of 4.970-99.40 mg/L (r=0.999 64) for MDI.The mean recovery rate was 100.9％ with the relative standard deviation of 3.2％ (n=6).The residue of MDI monomer in the three batches of samples was lower than the tolerable exposure.Therefore,it is a sensitive,rapid,accurate,specific method that can be used for the quality control of the residual MDI monomer in the hemodialysis catheter.

Complete Mitochondrial Genome of Echinostoma hortense (Digenea: Echinostomatidae)

Echinostoma hortense (Digenea: Echinostomatidae) is one of the intestinal flukes with medical importance in humans. However, the mitochondrial (mt) genome of this fluke has not been known yet. The present study has determined the complete mt genome sequences of E. hortense and assessed the phylogenetic relationships with other digenean species for which the complete mt genome sequences are available in GenBank using concatenated amino acid sequences inferred from 12 protein-coding genes. The mt genome of E. hortense contained 12 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and 1 non-coding region. The length of the mt genome of E. hortense was 14,994 bp, which was somewhat smaller than those of other trematode species. Phylogenetic analyses based on concatenated nucleotide sequence datasets for all 12 protein-coding genes using maximum parsimony (MP) method showed that E. hortense and Hypoderaeum conoideum gathered together, and they were closer to each other than to Fasciolidae and other echinostomatid trematodes. The availability of the complete mt genome sequences of E. hortense provides important genetic markers for diagnostics, population genetics, and evolutionary studies of digeneans.

Tissue engineering of vascular graft from decellularized arterial matrix and mesenchymal stem cells / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the method of constructing small-diameter vascular grafts from xenogenic decellularized arterial matrices and mesenchymal stem cells (MSCs).</p><p><b>METHODS</b>Porcine iliac arteries were decellularized by detergent and trypsin treatment. Histology, mechanical strength and porosity experiments were performed to evaluate the properties of decellularized matrices. MSCs were isolated from bone marrow of dogs and expanded ex vivo. Decellularized matrices were seeded with MSCs and further cultured in a pulsatile bioreactor. Morphological features of the tissue engineered grafts were assayed by HE staining and scanning electron microscopy.</p><p><b>RESULTS</b>After cell extraction, absence of cellular components and preservation of extracellular matrix were verified. Mechanical strength of decellularized matrices was slightly reduced compared with native arteries. Porosity of decellularized matrices was 94.9%. Decellularized matrices were successfully seeded with MSCs, which grew to a near-confluent monolayer under flow conditions and MSCs were highly elongated and oriented to the flow direction.</p><p><b>CONCLUSION</b>Small-diameter vascular grafts can be constructed by seeding MSCs onto xenogenic decellularized arterial matrices and culturing in a pulsatile bioreactor.</p>