[Clinical analysis on eight cases of intrahepatic arteriovenous fistula in hepatocellular carcinoma].
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Adult↗
Biomedical subjects
Ming Yan
Publications and source records attributed to Ming Yan.
cDNA cloning, expression, and mutagenesis of a PR-10 protein SPE-16 from the seeds of Pachyrrhizus erosus.
SPE-16 is a new 16kDa protein that has been purified from the seeds of Pachyrrhizus erosus. It's N-terminal amino acid sequence shows significant sequence homology to pathogenesis-related class 10 proteins. cDNA encoding 150 amino acids was cloned by RT-PCR and the gene sequence proved SPE-16 to be a new member of PR-10 family. The cDNA was cloned into pET15b plasmid and expressed in Escherichia coli. The bacterially expressed SPE-16 also demonstrated ribonuclease-like activity in vitro. Site-directed mutation of three conserved amino acids E95A, E147A, Y150A, and a P-loop truncated form were constructed and their different effects on ribonuclease activities were observed. SPE-16 is also able to bind the fluorescent probe 8-anilino-1-naphthalenesulfonate (ANS) in the native state. The ANS anion is a much-utilized "hydrophobic probe" for proteins. This binding activity indicated another biological function of SPE-16.
Amino Acid Sequence↗
Purification, characterization and preliminary crystallographic studies of a cysteine protease from Pachyrrhizus erosus seeds.
The proteins Spe31 and Spe32, named after their respective molecular weights of about 31 and 32 kDa, were purified simultaneously from the seeds of Pachyrrhizus erosus. They cannot be separated from each other by column chromatography. N-terminal sequence analysis indicated that they belonged to the papain family of cysteine proteases. An in-gel activity assay revealed that Spe31 possesses proteolytic activity while Spe32 only displays very weak activity for protein degradation. Both of them are glycoproteins as detected by the periodic acid and Schiff's reagent method. Crystals were obtained from the protein mixture by the hanging-drop vapour-diffusion method; they diffracted to a resolution of 2.61 A on an in-house X-ray source. The crystals belong to space group P4(1(3))2(1)2, with unit-cell parameters a = b = 61.96, c = 145.61 A. Gel electrophoresis under non-denaturing conditions showed that the protein crystallized was Spe31.
Amino Acid Sequence↗
Mapping dominant-negative mutations of anthrax protective antigen by scanning mutagenesis.
The protective antigen (PA) moiety of anthrax toxin transports edema factor and lethal factor to the cytosol of mammalian cells by a mechanism that depends on its ability to oligomerize and form pores in the endosomal membrane. Previously, some mutated forms of PA, designated dominant negative (DN), were found to coassemble with wild-type PA and generate defective heptameric pore-precursors (prepores). Prepores containing DN-PA are impaired in pore formation and in translocating edema factor and lethal factor across the endosomal membrane. To create a more comprehensive map of sites within PA where a single amino acid replacement can give a DN phenotype, we used automated systems to generate a Cys-replacement mutation for each of the 568 residues of PA63, the active 63-kDa proteolytic fragment of PA. Thirty-three mutations that reduced PA's ability to mediate toxicity at least 100-fold were identified in all four domains of PA63. A majority (22) were in domain 2, the pore-forming domain. Seven of the domain-2 mutations, located in or adjacent to the 2beta6 strand, the 2beta7 strand, and the 2beta10-2beta11 loop, gave the DN phenotype. This study demonstrates the feasibility of high-throughput scanning mutagenesis of a moderate sized protein. The results show that DN mutations cluster in a single domain and implicate 2beta6 and 2beta7 strands and the 2beta10-2beta11 loop in the conformational rearrangement of the prepore to the pore. They also add to the repertoire of mutations available for structure-function studies and for designing new antitoxic agents for treatment of anthrax.
Animals↗
Functional modification of pituitary somatotropes in the aromatase knockout mouse and the effect of estrogen replacement.
Available data on the influence of estradiol (E(2)) on GH levels remains controversial. A factor contributing to this uncertainty is a lack of knowledge of both E(2) action on somatotropes as well as the molecular mechanisms involved. In this study we investigated gene expression implicated in GH secretion in somatotropes derived from female aromatase knockout (ArKO) mice. In these mice E(2) production is blocked due to disruption of the Cyp19 gene encoding aromatase, the enzyme responsible for estrogen biosynthesis. The effect of E(2) replacement was also studied by in vivo treatment of mice with E(2) for 3 wk. It was demonstrated that somatotropes from ArKO mice had a low expression of GH, GH secretagogue receptor, GHRH receptor (GHRH-R), and pituitary-specific transcription factor (Pit-1). On the other hand, the somatotropes exhibited elevated expression of somatostatin receptors (sst1-5). Overall, these effects resulted in a reduction in GH secretion. E(2) replacement increased GHRH-R, Pit-1, and GH mRNA levels to 185%, 193%, and 157% and reduced the levels of sst1, sst2, sst4, and sst5 mRNA expression in ArKO mice, respectively. E(2) replacement did not affect the levels of pituitary estrogen (alpha and beta) and androgen receptor mRNA expression. It is concluded that the expression of important genes involved in GH synthesis in somatotropes of the female ArKO mouse are functionally down-regulated, and such a down-regulation is reversed to normal levels by E(2) replacement. The levels of GH secretagogue receptor, GHRH-R, and Pit-1 mRNA expression were also reduced, and sst1 and sst3 mRNA expression enhanced in aging ArKO and wild-type mice, resulting in a decrease in GH mRNA expression. It is suggested that aging is another important impact factor for the pituitary expression and regulation of GH mRNA in female mice.
Aging↗
Highly selective catalyst-directed pathways to dihydropyrroles from vinyldiazoacetates and imines.
Copper-catalyzed reactions of vinyldiazoacetates with imines occur via a pathway in which the activated imine undergoes electrophilic addition to the vinyldiazo compound, whereas reactions catalyzed by rhodium(II) proceed through a metal carbene to an intermediate iminiumylide. Both pathways exhibit high stereoselectivities.
Acetates↗
Catalysts with mixed ligands on immobilized supports. Electronic and steric advantages.
[reaction: see text] Immobilized dirhodium(II) catalysts having mixed chiral ligands enhance reactivity (AH = azetidinone) and influence stereoselectivity in cyclopropanation and carbon-hydrogen insertion reactions.
Azetidines↗
Protein ISGylation modulates the JAK-STAT signaling pathway.
ISG15 is one of the most strongly induced genes upon viral infection, type I interferon (IFN) stimulation, and lipopolysaccharide (LPS) stimulation. Here we report that mice lacking UBP43, a protease that removes ISG15 from ISGylated proteins, are hypersensitive to type I IFN. Most importantly, in UBP43-deficient cells, IFN-beta induces a prolonged Stat1 tyrosine phosphorylation, DNA binding, and IFN-mediated gene activation. Furthermore, restoration of ISG15 conjugation in protein ISGylation-defective K562 cells increases IFN-stimulated promoter activity. These findings identify UBP43 as a novel negative regulator of IFN signaling and suggest the involvement of protein ISGylation in the regulation of the JAK-STAT pathway.
Animals↗
[Therapy effects of fenofibrate on alcoholic fatty liver and drug-induced fatty liver in rats].
OBJECTIVE: To investigate the fat decreasing effects of fenofibrate on alcoholic fatty liver and drug-induced fatty liver in rats. METHODS: Alcoholic fatty liver and drug-induced fatty liver rats models were established. The two kinds of rats with fatty liver were seperatedly divided into fenofibrate treatment group (80 mg/kg daily) and control group without treatment. Rats were killed after four weeks, then the levels of serum triglycerides (TG), total cholesterol (TC), high density lipoprotein (HDL) and malondialdehyde (MDA), hepatic lipase (HL), lipoprotein lipase (LPL) both in serum and liver tissue were measured according to the Test Kits. Histopathological changes in liver was dyed with HE and observed under light microscope. RESULTS: After treatment by fenofibrate, in the serum of rats with alcoholic fatty liver, the level of TG decreased significantly (1.07 mmol/L 0.06 mmol/L vs 1.56 mmol/L 0.29 mmol/L, t=5.115, p<0.001), while the level of TC had no alteration. The levels of MDA both in serum and liver tissue decreased (1.10 nmol/L 0.22 nmol/L vs 1.26 nmol/L 0.21 nmol/L, t=0.592, p<0.05; 5.92 nmol/g 1.24 nmol/g vs 7.42 nmol/g 1.22 nmol/g, t=3.477, p<0.05, respectively), while the levels of HL, LPL in serum and liver tissue increased significantly (Serum: 0.053muEq/ml/h 0.006muEq/ml/h vs 0.037 muEq/ml/h 0.006muEq/ml/h, t=-5.086, p<0.001; 0.018 muEq/ml/h 0.004 muEq/ml/h vs 0.014muEq/ml/h 0.004muEq/ml/h, t=-2.485, p<0.05. Liver tissue: 0.075muEq/ml/h 0.010muEq/ml/h vs 0.065muEq/ml/h 0.007muEq/ml/h, t=-2.437, p<0.05; 0.022 muEq/ml/h 0.014 muEq/ml/h vs 0.008 muEq/ml/h 0.002 muEq/ml/h, t=-2.876, p<0.05). Fat content in liver decreased (26.01 mg/g 1.69 mg/g vs 71.45 mg/g 2.66 mg/g, t=-43.224, p<0.001). The pathological changes of liver in fenofibrate-treated rats with alcoholic fatty liver were improved. For the drug-induced fatty liver rats, fenofibrate treatment group had no difference from the untreated control group. CONCLUSION: Fenofibrate can significantly decrease the fat content in liver tissue of rats with alcoholic fatty liver, as well as ameliorating liver pathological changes. But fenofibrate has no effect on drug-induced fatty liver.
Animals↗
[Relationship between ALDH gene polymorphism and alcoholic liver diseases].
OBJECTIVE: To study the relationship between aldehyde dehydrogenase (ALDH) gene polymorphism and alcoholic liver disease, and investigate the genetic pathogenesis of alcoholic liver disease (ALD). METHODS: PCR, restriction endonuclease and electrophoresis were used, to detect the genotypes and alleles frequencies of ALDH gene in patients in the control group, alcohol dependent group and ALD group, and each group contained 20 patients. RESULTS: The frequencies of ALDH2*1 and ALDH2*2 allele had statistic significance between control group and ALD group (x2=4.80, P<0.05), and no statistic significance between control group and alcohol dependent group. ALDH2*1/*1 was predominant in alcohol dependent group and ALD group, while ALDH2*2/*2 was not detected. CONCLUSIONS: The gene polymorphism of ALDH is close to ALD. The allele of ALDH2*2 may be a negative risk factor for the developing of ALD
Adult↗
Tyrosine kinase inhibitors suppress alpha1-adrenoceptor mediated contraction in human radial, internal mammary arteries and saphenous vein.
The aim of this study is to determine whether the tyrosine kinase plays a role in the contractile response of human radial artery (RA), internal mammary artery (IMA) and saphenous vein (SV) to alpha(1)-adrenoceptor (AR) stimulation. The tyrosine kinase inhibitors, genistein and tyrphostin, significantly inhibited alpha(1)-AR mediated contractile response in a dose-dependent and non-competitive manner. Genistein at 10 microM inhibited 39%, 54% and 72% of PE-induced maximum contraction, and tyrphostin at 50 microM inhibited 41%, 68% and 39% of the contraction in the human RA, IMA and SV respectively. These results suggest that tyrosine kinases participate in regulation of signal transduction that is associated with alpha(1)-AR mediated contractile response in human blood vessels.
Adrenergic alpha-1 Receptor Antagonists↗
In vitro transcription and start site selection in Schizosaccharomyces pombe.
We have used the fission yeast Schizosaccharomyces pombe to establish both a biochemical and genetic system to study the roles of general transcription factors in transcription initiation. Extracts were prepared that faithfully transcribed S. pombe promoters and the results confirm that, in contrast to the budding yeast Saccharomyces cerevisiae, in vitro transcription in S. pombe initiates near to the TATA element. S. pombe transcription relies on upstream activation sequence elements and these can be replaced successfully with sites for binding Gal4-VP16 activators. Although it is mammalian-like in these respects, S. pombe initiation uses an unusual scanning mechanism. This directs initiation, preferentially using purines, within a narrow window approximately 25-40 base-pairs downstream from the edge of the TATA element. Genetic experiments showed that this scanning mechanism was associated with the properties of the TFIIB polypeptide. When human TFIIB was expressed in S. pombe, it was accepted by the endogenous transcription machinery and caused initiation to be restricted to the closer edge of this window, corresponding to the distance in humans. Preliminary experiments suggested that S. cerevisiae TFIIB was not accepted. The results enlarge the potential for using fission yeast to study the properties of general transcription factors such as TFIIB in choosing the sites at which transcription initiates.
Animals↗
[Propofol depresses c -fos expression of NOS neurons in the spinal cord of rats with inflammatory pain].
In formalin pain model, the effect of propofol on Fos expression in the spinal cord was examined by means of c -fos oncogene immunohistochemistry and NADPH-d histochemistry. Fos-like immunoreactive (FLI) neurons were mainly found in the ipsilateral dorsal horn after injection of formalin, some of which were FLI/NOS double-labeled neurons. Most of the FLI or FLI/NOS double-labeled neurons were observed in the medial part of lamina and the outer lamina . Before or after injection of formain, i.p. injection of propofol significantly decreased the number of FLI and FLI/NOS double-labeled neurons in all laminae (P<0.05 or P<0.01). By single i.p. injection of propofol or normal saline, few FLI neurons were found in the spinal cord. The results suggest that the antinociceptive function of propofol is possibly involved in the depression of the NOS neurons in the spinal cord.
Animals↗
Effective and highly stereoselective coupling with vinyldiazomethanes to form symmetrical trienes.
Diazo coupling reactions are capable of forming E,E,E-trienes from cinnamaldehydes in good yield. An efficient methodology is reported for the production of styryldiazomethanes that are subsequently used with catalysis for coupling and for cyclopropanation. A vast difference in product selectivity is seen with styryldiazomethane generated from the corresponding hydrazone via manganese dioxide oxidation and that formed in situ by treatment of the tosylhydrazone sodium salt of cinnamaldehyde with transition metal catalysts. This observation impacts understanding of the reaction mechanism for diazo decomposition.
Alkenes↗
Orexin-A augments voltage-gated Ca2+ currents and synergistically increases growth hormone (GH) secretion with GH-releasing hormone in primary cultured ovine somatotropes.
Orexins are recently discovered neuropeptides that play an important role in the regulation of hormone secretion, and their receptors have been recently demonstrated in the pituitary. The effects of orexin-A on voltage-gated Ca2+ currents and GH release in primary cultured ovine somatotropes were examined. The expression of orexin-1 receptor was demonstrated by RT-PCR in ovine somatotropes, from which Ca2+ currents were also isolated as L, T, and N currents. Application of orexin-A (100 nM) significantly and reversibly increased only the L current, and coadministration of orexin-A and GHRH (10 nM) showed an additive effect on this current, but no effect of orexin-A was observed on either T or N current. Furthermore, the orexin-A-induced increase in the L current was completely abolished by the inhibition of protein kinase C (PKC) activity using calphostin C (100 nM), phorbal 12,13-dibutyrate pretreatment (0.5 micro M) for 16 h or specific PKC inhibitory peptide PKC(19-36) (1 mM). However, the increase in L current by orexin-A was sustained when cells were preincubated with a specific protein kinase A blocker H89 (1 micro M) or a specific intracellular Ca2+ store depleting reagent thapsigargin (1 micro M). Finally, orexin-A alone did not significantly increase GH release, but coadministration of orexin-A and GHRH showed a synergistic effect on GH secretion in vitro. Our results therefore suggest that orexin-A may play an important role in regulating GHRH-stimulated GH secretion through the enhancement of the L-type Ca2+ current and the PKC-mediated signaling pathway in ovine somatotropes.
Animals↗
[Construction of a proteomic map database].
The first proteomic map database of China will be published by Bioinformation Center and Research Center of Proteomics, Shanghai Institutes for Biological Sciences, the Chinese Academy of Sciences.The database consists of physical layer, link layer and interfacial layer. As Java technique was introduced to construct the database system, the database does not depend on special working platform. With the search instruments users can easily look through the proteomic map and get concrete information of proteins they are interested in.
China↗
Cloning and Expression of Luffin-b cDNA from the Seeds of Luffa cylindrica.
Luffin-b with Mr. 28 kD, isolated from the seeds of Luffa cylindrica,is one of the most toxic single chain plant ribosome inactivating proteins. The cDNA sequence of luffin-b was already reported by Kataoka in 1992. In this work, the luffin-b gene(lufB) coding sequence was cloned from the fresh seeds of Luffa cylindrica by RT-PCR, and the coding sequence of the gene was shown to be identical with that determined by Kataoka. The lufB expression plasmid was constructed by inserting the lufB cDNA fragment into vector pET24a( ), and the pET24a( )- lufB vector was expressed in E.coli by 0.5 mmol/L IPTG induction. The recombinant product, which mainly existed in inclusion bodies, was identified by SDS-PAGE and Western blotting. The recombinant luffin-b, which was renatured by dialysis with step by step decreasing concentration of urea, showed high activity of ribosome inactivation.
Journal Article↗
Preparation and Use of a Monoclonal Antibodyagainst Luffin b.
Luffin b is one of the most toxic single chain plant ribosome inactivating proteins. It has been successfully used to prepare an immunotoxin against human melanoma cells. Two strains of hybridomas (1E5 and 2E1) were screened out using cell fusion technique which steadily secreted monoclonal antibodies against luffin b. These antibodies specifically reacted with luffin b. The affinity constants of 1E5 and 2E1 monoclonal antibodies were determined to be 1.1x10(9) mol(-1).L and 7.5x10(8) mol(-)1.L, by RIA,respectively. An immunoaffinity gel composed with the 1E5 monoclonal antibody and Sepharose 4B was prepared. The luffin b was successfully purified by one step immunoaffinity chromatography from the crude extract of Luffa cylindrica seeds. An immunoconjugate 1E5-HRP was also prepared and it was successfully used in Western blotting for detection of recombinant luffin b from E.coli total proteins.
Journal Article↗