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X J Wu

Publications and source records attributed to X J Wu.

At least 19 recordsLinked to original sources
PubMed2001

Electron crystallographic image-processing investigation and superstructure determination for (Pb0.5Sr0.3Cu0.2)Sr2(Ca0.6Sr0.4)Cu2Oy.

An electron crystallographic image-processing technique based on the combination of high-resolution electron microscopy and electron diffraction has been developed to investigate the commensurate structural modulation in the high-Tc superconductor (Pb0.5Sr0.3Cu0.2)Sr2(Ca0.6Sr0.4)Cu2Oy. After symmetry averaging, a structure image was obtained by image deconvolution at the resolution limited by that of the electron microscope. Then phase extension was employed to enhance the image resolution up to about 1.25 A by means of the electron diffraction data corrected with an empirical method. In the final projected potential map, the occupational and/or positional modulation is clearly observed for all atoms, including oxygen. The key points of determining superstructures by the technique are studied and discussed.

Journal Article↗
PubMed2000

Free radical scavenging and inhibition of lipid peroxidation by magnesium lithospermate B.

AIM: To study the effect of magnesium lithospermate B (MLB) on the lipid peroxidation and on its free radical scavenging activity. METHODS: MLB was incubated in rat tissue homogenate or in a free radical generating system. MLB induced inhibition of lipid peroxidation and its scavenging activity on superoxide anions and hydroxyl radicals was studied using colorimetric estimation. RESULTS: MLB inhibited the lipid peroxidation induced by either an auto-oxidant or Fe2+/VitC in vitro, in the liver homogenate, the inhibitory rate of MLB (10 mg/L) being 69.2% and 57.7%, respectively. MLB (25 and 50 mg/kg) decreased the amount of thiobarbituric acid reactive substances (TBARS) in rat serum, liver, kidney, and heart. However, it did not inhibit the lipid peroxidation of brain homogenate ex vivo. MLB scavenged superoxide anions generated from xanthine/xanthine oxidase system and iron-dependent hydroxyl radicals. CONCLUSION: MLB is an inhibitor of lipid peroxidation and scavenge superoxide anions and hydroxyl radicals both in vitro and ex vivo.

Animals↗
PubMed1999

Cloning of a beta integrin subunit cDNA from an embryonic cell line derived from the freshwater mollusc, Biomphalaria glabrata.

A cDNA encoding an integrin subunit was cloned and structurally characterized from an embryonic cell line derived from Biomphalaria glabrata, snail intermediate host of the human blood fluke Schistosoma mansoni. Cells of the B. glabrata embryonic (Bge) snail cell line were initially tested for their sensitivity to the integrin-specific tetrapeptide inhibitor Arg-Gly-Asp-Ser (RGDS). Washed Bge cells when exposed to 0.5 to 2.0mM of RGDS were significantly inhibited in their ability to spread on a glass substrate. Spreading inhibition was specific, since a control peptide Arg-Gly-Glu-Ser (RGES) did not have the same effect. RT-PCR was performed using previously reported degenerate oligonucleotide primers to the ligand binding domain (LBD) of known beta integrin subunits and Bge cDNA. A 137 bp fragment was amplified, TA-cloned, sequenced, and the na and deduced aa sequences were compared with other beta integrins. Databank analysis showed that the 137 bp product shared >/=55.6% aa similarity to other beta integrin LBDs. Southern and northern blot analyses using the 137 bp sequence as a probe revealed binding to Bge genomic DNA restriction fragments and to an approximately 8 kb poly-(A)+RNA transcript, respectively. An exact 5' primer synthesized to the 137 bp product and an oligo-d(T) primer then were used to amplify from Bge cDNA, a partial beta integrin sequence of 2285 bp that contained a 1971 bp ORF. The remaining upstream coding region was obtained using 5' RACE methods. The complete ORF, consisting of 2364 bp, encoded a 788 aa sequence with shared similarity to other known beta integrins (44.6-61.5%). Sequence and structural comparisons, which include a characteristic LBD, a series of three homologous cysteine-rich repeats, membrane proximal sequence (LLTFIHD), cytoplasmic NPXY motifs, and predicted domain lengths of the molluscan protein, clearly identifies it as an integrin homologue. This report represents the first cloning of a cDNA putatively encoding an integrin subunit from molluscan cells, and establishes the Bge cell line as a model for studying cellular adhesion in molluscs at the molecular level.

Amino Acid Sequence↗
PubMed1999

Placental site nodules and plaques: a clinicopathological and immunohistochemical study of 25 cases with ultrastructural findings.

Placental site nodules or plaques (PSN-Ps) are nodular benign lesions of the intermediate trophoblast (IT) cells in the endometrium, endocervix, superficial myometrium or fallopian tube, occurring after a remote intrauterine pregnancy. We present a study of 25 cases of PSN-Ps These lesions occurred in patients aged 18 to 44 years. Most were discovered incidentally in endometrial curettage specimens. The specimens were received as part of clinical investigations for menorrhagia, per vaginal bleeding or pelvic pain. None of the PSN-Ps was visible grossly. Microscopically, they were mostly multiple, well-circumscribed, oval or plaque-like cellular nodules. The IT cells typically had abundant vacuolated or eosinophilic cytoplasm. The nuclei were irregular, large, hyperchromatic, often degenerate-looking and either mononucleated, multinucleated or multiclefted. Hyalinization surrounding individual or groups of IT cells, or located in the centre of the nodules, was a constant feature in all cases. The lesional cells were strongly immunoreactive to CAM 5.2, 34 beta E12, AE1/AE3, EMA and vimentin. Some cases showed focal positivity to HCG and HPL. PLAP staining was consistently negative. Ultrastructurally, the IT cells showed prominent nuclear variation in size and shape. The abundant, vacuolated cytoplasm contained some rough endoplasmic reticulum and loosely arranged filaments. This study describes the clinicopathological and immunophenotypic features of 25 cases of PSN-Ps including the ultrastructural findings of one case.

Adolescent↗
PubMed1998

Spontaneous closure of muscular ventricular septal defect identified by echocardiography in neonates.

Muscular ventricular septal defects were diagnosed by echocardiography in 97 neonates within 7 days of birth. In 82 of the neonates (84.5%), the defect was solitary, while 15 had multiple defects. The solitary defects was located at mid-septal, apical, anterior and inlet locations in 42 (51.2%), 21 (25.6%), 14 (17.1%) and 5 (6.1%) neonates, respectively. Multiple defects occurred in the apical, anterior and mid-septal areas. The diameter of the solitary defects ranged from 1 to 6 mm (2.3 +/- 0.8 mm), while the multiple lesions were 1 to 4 mm in diameter (2.1 +/- 0.8 mm) in 28 instances in which they could measured. It proved possible to follow 79 of the patients for period of 10 to 13 months. The defects closed spontaneously in 56 (84.8%) of 66 patients with a single defect, and in 7 (53.8%) of 13 of those with multiple defects (P<0.05). For the solitary defects, the position and size were factors determining the likelihood and speed of closure. Defects located at the apical septum, or defects larger than 4 mm in diameter, closed slowly and at a later stage. Echocardiography is an useful technique in establishing of natural history of muscular ventricular septal defects encountered in neonates.

Echocardiography, Doppler↗
PubMed1998

Transfection and heat-inducible expression of molluscan promoter-luciferase reporter gene constructs in the Biomphalaria glabrata embryonic snail cell line.

Studies were initiated to begin developing a genetic transformation system for cells derived from the freshwater gastropod, Biomphalaria glabrata, an intermediate host of the human blood fluke Schistosoma mansoni. Using a 70-kD heat-shock protein (HSP70) cDNA probe obtained from the B. glabrata embryonic (Bge) cell line, we cloned from Bge cells a complete HSP70 gene including a 1-kb genomic DNA fragment in its 5'-flanking region containing sequences indicative of a HSP promoter. Identified in the 5'-half (416 nucleotides) of this genomic fragment were TATA and CAAT boxes, two putative transcription initiation sites, and a series of palindromic DNA repeats with shared homology to the heat-shock element consensus sequence (Bge HSP70(0.5k) promoter). The 3'-half of this upstream flanking region was comprised of a 508-base intron located immediately 5' of the ATG start codon. To determine the functionality of the putative snail promoter sequence, Bge HSP promoter/luciferase (Luc) reporter gene constructs were introduced into Bge cells by N-(1-(2,3-dioleoyloxy) propyl)-N,N,N-trimethylammonium methylsulfate (DOTAP)-mediated transfection methods, and assayed for Luc activity 48 hr following a 1.5-hr heat-shock treatment (40 degrees C). Compared with control vectors or the Bge HSP70(0.5k/1.0k) promoter constructs at 26 degrees C, a 10- to 300-fold increase in Luc expression was obtained only in the Bge HSP70 promoter/Luc-transfected cells following heat-shock. Results of transfection experiments demonstrate that the Bge HSP70(0.5k) DNA segment contains appropriate promoter sequences for driving temperature-inducible gene expression in the Bge snail cell line. This report represents the first isolation and functional characterization of an inducible promoter from a freshwater gastropod mollusc. Successful transient expression of a foreign reporter gene in Bge cells using a homologous, inducible promoter sequence now paves the way for development of methods for stable integration and expression of snail genes of interest into the Bge cell line.

Animals↗
PubMed1997

Determination of thiamphenicol in human plasma by micellar electrokinetic capillary chromatography.

A micellar electrokinetic chromatographic method is described for the determination of thiamphenicol in human plasma. The plasma sample was basified by adding K2HPO4 and was then extracted with ethyl acetate. After the solvent was evaporated, the residue was reconstituted in water. Approximately 40 nl of the solution were injected hydrodynamically. The running buffer was 20 mM borate (pH 9.2) containing 40 mM sodium dodecyl sulfate and 10% acetonitrile. The applied voltage was 18 kV and the detector wavelength was set at 195 nm. On-column sample stacking was achieved during the analysis to enhance the sensitivity; the limit of quantitation was 0.1 microg/ml. Linearity was over the range of 0.2 to 10 microg/ml. Recovery was 93.7+/-3.3%, the intra-day precision and accuracy was 99.6+/-2.8%; the inter-day precision and accuracy was 98.4+/-3.4%. The concentration of thiamphenicol in human plasma from eight volunteers was measured after administering thiamphenicol capsules orally.

Acetonitriles↗
PubMed1997

Heat-shock response in a molluscan cell line: characterization of the response and cloning of an inducible HSP70 cDNA.

Sublethal heat-shock of cells of the Bge (Biomphalaria glabrata embryonic) snail cell line resulted in increased or new expression of metabolically labeled polypeptides of approximately 21.5, 41, 70, and 74 kDa molecular mass. Regulation of this response appeared to be at the transcriptional level since a similar protein banding pattern was seen upon SDS-PAGE/fluorographic analysis of polypeptides produced by in vitro translation of total RNA from cells subjected to heat shock. Using a yeast (Saccharomyces cerevisiae) 70-kDa heat-shock protein (HSP70) probe to screen a cDNA library from heat-treated Bge cells, we isolated a full-length cDNA clone encoding a putative Bge HSP70. The cDNA was 2453 bp in length and contained an open reading frame of 1908 bp encoding a 636-amino-acid polypeptide with calculated molecular mass of 70,740 Da. Comparison of a conserved region of 209 amino acid residues revealed > 80% identity between the deduced amino acid sequence of Bge HSP70 and that of yeast (81%), the human blood fluke Schistosoma mansoni (for which B. glabrata serves as intermediate host) (81%), Drosophila (81%), human (84%), and the marine gastropod Aplysia californica (88%, 90%). In addition to the extensive sharing of sequence homology, the identification of several eukaryotic HSP70 signature sequences and an N-linked glycosylation site characteristic of cytoplasmic HSPs strongly support the identity of the Bge cDNA as encoding an authentic HSP70. Results of a Northern blot analysis, using Bge HSP70 clone-specific probes, indicated that gene expression was heat inducible and not constitutively expressed. This is the first reported sequence of an inducible HSP70 from cells originating from a freshwater gastropod and provides a first step in the development of a genetic transformation system for molluscs of medical importance.

Amino Acid Sequence↗
PubMed1994

[Preliminary report on portal hypertension treated by transjugular intrahepatic portosystemic stent shunt].

Transjugular intrahepatic portosystemic stent shunt (TIPSS) was carried out in 50 cases of liver cirrhosis with portal hypertension. An average Child-Pugh score in these cases was 10.33 +/- 2.34. Except for 5 cases with portal vein occlusion, the technical success rate of in 45 cases was 95.6%. Acute variceal bleeding was immediately controlled. Portal pressure was reduced by 1.36 +/- 0.48 kPa. Esophageal varices and ascites disappeared. The shrink of spleen, the reducing of body weight were also observed in a week following TIPSS. The velocity of blood flow in stents was 85.61 +/- 35.83 cm/s. Follow-up of 1-9 months found norebleeding and ascites. The velocity of blood flow in stents was 83.83 +/- 34.74 cm/s. Three patients died of liver failure and variceal rebleeding within a month after TIPSS. Slight encephalopathy was observed in 6 cases.

Adult↗
PubMed1992

[Separation and identification of impurities in mifepristone].

In this paper we presented details of methods for the TLC and HPLC separation of mifepristone and its impurities. The results showed that Chinese mifepristone contained five impurities. The major one was isolated by sillca gel column chromatography and thin layer chromatography. On basis of its UV, IR, EIMS and 1HNMR spectral analysis and by comparison with reference substance, it was identified as (11 beta, 17 beta)-11-[(4-methylamino)phenyl]-17-hydroxy-17-(1-propyny)-estra-4 ,9-dien-3 - one. Meanwhile, TLC analysis indicated that French mifepristone contained the same impurity.

Chromatography, High Pressure Liquid↗
PubMed1990

Inhibition of uncoating of tobacco mosaic virus particles in protoplasts from transgenic tobacco plants that express the viral coat protein gene.

The uncoating of tobacco mosaic virus (TMV) particles in protoplasts isolated from leaves of transgenic tobacco plants that express the TMV coat protein gene was investigated. Extracts of these protoplasts collected up to 1 hr after inoculation with TMV contained fewer of the complexes ("striposomes") thought to be involved in cotranslational disassembly of virus particles than did extracts of protoplasts that do not express the viral coat protein gene. These results are consistent with the hypothesis that TMV coat protein-mediated resistance is at least in part the result of inhibition of the uncoating of the virus particles in the inoculum.

Capsid↗
PubMed1990

[Surgical treatment of chronic constrictive pericarditis].

From April, 1969 to December, 1988, partial pericardiectomy was performed in 78 patients with chronic constrictive pericarditis. The long-term follow-up study in 60 patients showed a satisfactory functional result. The authors considers that the median sternotomy is a better approach, the effectiveness of operation should be gauzed by dropping the vena cave pressure below 140 mmH2O, resection of pericardium from left to right is logical, and rational use of cardiotonic agents is important.

Adolescent↗
PubMed1990

[Development of a new system for selection of A. foetidus transformed with foreign genes by using thymidine kinase gene as a marker and expression of HBsAg gene in A. foetidus].

A new system for selection of transformed Aspergillus foetidus was reported. In this system, TK- A. foetidus which were constructed by homologous recombination of mutated TK gene of vaccinia virus with TK gene of A. foetidus were screened by adding BUdR in agar plates. Conditions for screen of TK+ A. foetidus strain, transformation of A. foetidus and selection of transformed TK- A. foetidus have been studied. By using this system, several transformed A. foetidus which contained HBsAg gene derived bf a promoter H8 cloned from genomic DNA of A. foetidus were isolated. It was demonstrated that HBsAg gene was integrated into the chromosome DNA of A. foetidus by Southern blot after many passages of spores. ELISA showed that HBsAg was positive in the growth medium (p/n = 20). The 22 nm particles which were very similar to the HBsAg particles in human serum were found in the growth medium by immunoelectromicroscope. Western blot also gave the specific bands. All these data showed that HBsAg gene was expressed in A. foetidus and the products were secreted into the growth medium. The selection system using TK gene as marker could generally be used to study the expression of foreign gene in A. foetidus.

Aspergillus↗
PubMed1990

[An experimental study of the basic properties of drug microspheres and target treatment of rats with liver tumor].

This experimental hepatic artery embolization with Camptothecin (CPT) albumin microspheres was performed in normal rats and rats with liver tumor. The basic properties of the CPT albumin microspheres and the effects of target treatment on rats with liver tumor were studied. The results showed that the concentration of the drug released into hepatic vein was almost stable for over 3 hours after hepatic arterial infusion of CPT albumin microspheres, the partial and complete recovery of hepatic artery inflow occurred within 50-70 days after embolization. Pathological examination revealed many irreversible damages of the liver, and the tumor vessels and stains disappeared after hepatic arterial embolization, some of the tumor were decreased in size and had complete necrosis. Therefore, CPT albumin microspheres are peripheral biodegradable embolizatic substances with the property of slowly drug-releasing. It can exert the effect of chemoembolization in treating the hepatic malignant tumor, alleviating the toxic reaction of CPT and increasing the patient's tolerance to CPT.

Animals↗
PubMed1989

[Use of a narrow pedicled cross-finger flap to repair defects of the fingertip].

A narrow pedicled cross-finger flap procedure for repair of fingertip defect is described. Its shape resembles that of the so-called flag flap. This technique was applied to 15 cases (17 fingers) and satisfactory results were obtained. The advantages include easy to rotate, comfortable positioning and avoidance of joint contracture.

Adolescent↗