Advances in endoscopic therapy for benign distal biliary strictures / 临床肝胆病杂志

Benign distal biliary strictures (BDBS) are fibrous tissue proliferation and biliary stricture caused by long-term stimulation of the affected bile ducts due to non-neoplastic factors such as iatrogenic injury, chronic inflammation, and bile duct stones, which further leads to recurrent cholangitis, obstructive jaundice, and liver impairment. Relieving distal biliary obstruction and maintaining bile duct patency for a long time are the core of the treatment of BDBS. With the continuous innovation of endoscopic retrograde cholangiopancreatography techniques, new techniques such as endoscopic stenosis dilatation, stent implantation, and magnetic compression anastomosis are gradually becoming effective treatment methods for BDBS. This article elaborates on the advances in endoscopic therapy for BDBS, so as to provide a reference for clinical research.

Molecular Cloning and Characterization of Two Hommologues of Yeast Sir2 Gene in the Parasitic Protist Trichomonas vaginalis / 热带医学杂志

Objective To screen cell growth and senescence-related genes of the parasitic pmtist Trichomonas vaginalis,we launched an EST program and isolated two cDNA clones from a T.vaginalis cDNA library,which showed high homology in deduced amino acid sequences to yeast Sir2 and designated as TvSir2 and TvSir2-like.Method The cDNA sequence of TvSIR2 had a length of 1034 base pairs (bp) with an open reading frame of 915 bp,and TvSIR2-like,1214 bp with an open reading frame of 1116 bp.Result The two deduced amino acid sequences shared all the three conserved cole domains with yeast Sir2 and its homologues,suggesting that the two clones were Sir2 homologues. A cDNA fragment from each cDNA clone was subvloned into the expression vector pET-41a.The expression of the fusion proteins in E.coli BL21 stains was induced by isopropylthio-β-D-galactoside (IPTG).Two anti-sera were prepared by immunizing two guinea pigs with the purified fusion proteins, Western-blot analysis demonstrated that each anti-serum reacted with the corresponding recombinant protein and detected a clear band (TvSir2,34 000 Mr;TvSir2-like,42 000 Mr)in protein extracts of the protist.Immunofluolescence techniques showed that TvSir2 and TvSir2-like proteins were both localized in the legions of perinuelear (ER) and Golgi complex.Conclusion Our data suggest that TvSir2 and TvSir2-like were two members of Sir2 family.Their biological functions in the protist would be further studied.

Cloning of LASS1 Gene and Primary Study on The Association of Its Expression With Neuron Aging in Rat Cerebral Cortex / 生物化学与生物物理进展

LA G1 was identified as a gene that is differentially expressed during the yeast replicative life span and was shown to play a role in determining yeast longevity. The cDNA of rat LASS1, the mammalian homolog of yeast LA G1, was cloned from rat cerebral cortex and sequenced, which is different to the predicted sequence in the GenBank. Sequence analysis revealed that this cDNA clone contains an open reading frame of 1 053 bp. The deduced amino acid sequence has 350 residues and shares a predicted Laglp motif and a TLC domain conserved in Lag1 proteins. Total RNAs were isolated from rat cerebral cortices at varying ages: newborn, one month, six months, twelve months, and twenty-four months. Semi-quantitative RT-PCR and Northern blot analysis were performed to analyze the LASS1 expression level in rat cerebral cortex tissues at varying ages. Senescence-associated β-galactosidase (SA-β-gal) activity was firstly used as a biomarker for assessing senescence in rat neurons. The results showed that LASS1 expression was upregulated from newborn to adult rats (1～6 month) and declined in aged cortex. SA-β-gal staining positive neurons significantly increased in the aged cerebral cortex. The age-related expression alternation of LASS1 in rat cerebral cortex provides an important clue in exploring the role of LASS1 in mammalian neuron aging.