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Wei Lin

Publications and source records attributed to Wei Lin.

85 records · Page 5Linked to original sources
PubMed2003

Comparative study on apoptosis induction of SMMC7721 and Vero cells by Clostridium difficile toxin A.

BACKGROUND & OBJECTIVE: Clostridium difficile is recognized as a frequent cause of antibiotic-induced diarrhea. This study was designed to investigate whether Clostridium difficile toxin A might induce apoptosis on human hepatoma cell line SMMC7721 and African green monkey kidney Vero cells. METHODS: Highly purified toxin A was obtained by bovine thyroglobulin affinity purification followed by ion exchange chromatography on Q sepharose. The apoptosis induction of toxin A was examined on SMMC7721 cells with Vero cells as a control. Inhibition of proliferation was measured by MTT assay. Morphological assessment of apoptosis was performed with fluorescence and electronic microscopy. DNA fragmentation was observed by agarose gel electrophoresis. Cell cycle distribution was analyzed by flow cytometry. RESULTS: Toxin A (0.293-4.690 mg x L(-1) ) inhibited proliferation of SMMC7721 and Vero cells in a time- and concentration-dependent manner. Morphological changes of typical apoptosis showed that SMMC7721 had a higher percentage of apoptosis than Vero cells. Agarose gel electrophoresis of DNA from SMMC7721 treated with toxin A for 48 hours revealed a "ladder" pattern. CONCLUSION: Clostridium difficile toxin A induced apoptosis of SMMC7721 and Vero cells. The apoptosis induction on SMMC7721 cells was more effective than that on Vero cells.

Animals↗
PubMed2003

[Relationship between cyclins and prognosis of acute leukemia].

BACKGROUND & OBJECTIVE: Cell proliferation and differentiation are directed by cell cycle mechanism. When tumor cells proliferate abnormally, cyclins, which are positive agents of cell cycle, may be expressed abnormally at the same time. Now many references proved that cyclins are highly expressed in solid tumors. This study was designed to investigate the relationship between expression of cyclins and prognosis of acute leukemia. METHODS: Sixty-eight cases of acute leukemia were enrolled. Reverse transcription polymerase chain reaction (RT-PCR) was performed on tumor samples to examine the expression of cyclin A, cyclin D, cyclin E. All samples were divided into three groups: acute leukemia in complete remission (12 cases), newly diagnosed acute leukemia (16 cases) and refractory leukemia (40 case). Samples of benign hemopoietic patients were used as normal control (15 cases). RESULTS: All the 15 cases in the control group were negative of cyclin mRNA. No difference of cyclin A mRNA expression was shown between control group and the three experiment groups (P >0.05). But expression of cyclin D and cyclin E mRNA was significantly different between them (P< 0.01). There was no difference of expression of cyclin D and cyclin E mRNA among CR patients with acute leukemia(P >0.05), while the expression of cyclin D mRNA is significantly higher than that of cyclin E in refractory leukemia group. Furthermore the expression of cyclin D mRNA in recurrent refractory leukemia patients is significantly higher than that newly diagnosed cases (P< 0.05). All cyclins mRNA positive cases were divided into single cyclin gene expressed group and multiple cyclins gene expressed group. The positive rates of them were counted. No difference was found between complete remission group and refractory leukemia group (P >0.05). CONCLUSION: Cyclin D may act as a prognostic marker for acute leukemia. The amount of cyclins expressed cannot be used as a prognostic factor for acute leukemia.

Acute Disease↗
PubMed2003

[An experimental research in the inhibiting effect of bFGF-MAb on the growth of ovarian cancer cells and transplanted tumor].

OBJECTIVE: To investigate whether the monoclonal antibody of basic fibroblast growth factor (bFGF-MAb) inhibits the proliferation, invasion and angiogenesis of ovarian cancer. METHODS: 1. Human ovarian cancer cells SKOV3 were planted in 24-well dishes, to which was added bFGF-MAb at different concentrations, and crystal violet staining was performed daily for 8 days, then cell numbers were counted by OD490 determination. 2. SKOV3 were transplanted intraperitoneally to BALB/c nude mice. One week later, bFGF-MAb was injected intraperitoneally twice a week, and the survival time of nude mice, the number and weight of the metastatic tumors on the mensentery were observed or measured. 3. Intratumoral microvessel density(MVD) was measured by immunohistochemical staining for CD31. RESULTS: 1. bFGF-MAb inhibited the proliferation of SKOV3 in the concentration-dependent manner (P < 0.05). 2. The average survival time of nude mice in bFGF-MAb group increased by 10 days over that of control. 3. The average number and weight of metastatic tumors on mensentery in bFGF-MAb group constituted 70.6% and 69.2% of those in control group, respectively. 4. The MVD in bFGF-MAb group accounted for 62.8% of the MVD in control group. CONCLUSION: bFGF-MAb can inhibit the proliferation and angiogenesis of ovarian cancer markedly, so it promises to have application in the biological treatment of ovarian cancer.

Animals↗
PubMed2003

[The effect of basic fibroblast growth factor in ovarian cancer growth and angiogenesis].

OBJECTIVE: To investigate whether basic fibroblast growth factor (bFGF) can induce the proliferation, invasion and angiogenesis of ovarian cancer or not. METHODS: Human ovarian cancer cell lines SKOV(3) 1 x 10(4)/ml were plated in 24-well dishes, bFGF at 5, 10,15 and 20 ng/ml was added and crystal violet staining was given daily for 8 days, cell numbers were counted by determining OD490. SKOV(3) cells were plated in the center of 50% extra cellular matrix gel, bFGF at 5 and 10 ng/ml was added and the migration distance of cells was measured daily. SKOV(3) 5 x 10(7)/ml were transplanted to BALB/c nude mice subcutaneous. One week later, bFGF, bFGF-MAb or 0.9% nature sodium was injected subcutaneously surrounding the tumor twice a week. Eight weeks later, the experiment ended and the volume of the tumors were measured. Intratumoral microvessel density (MVD) was measured by immunohistochemistry staining for factor VIII. RESULTS: bFGF at 0-10 ng/ml could stimulate the proliferation of SKOV(3) concentration dependently (P<0.05). On the fifth day, the cell proliferation in 10 ng/ml group was 121% above control. bFGF could stimulate the invasion of SKOV(3) concentration dependently (P<0.05). On the seventh day, the migration distance in 5 ng/ml group was 1.16 cm and 153% above control, and that in 10 ng/ml group was 1.86 cm and 245% above control. The average volume of transplanted tumors and MVD in bFGF group were 180% and 146% above control respectively those in bFGF-MAb group were 63.7% and 62.8% above control respectively. CONCLUSION: bFGF can stimulate proliferation, invasion and angiogenesis of ovarian cancer markedly; bFGF-MAb can inhibit the angiogenesis and growth of ovarian cancer.

Animals↗
PubMed2002

A draft sequence of the rice genome (Oryza sativa L. ssp. indica).

We have produced a draft sequence of the rice genome for the most widely cultivated subspecies in China, Oryza sativa L. ssp. indica, by whole-genome shotgun sequencing. The genome was 466 megabases in size, with an estimated 46,022 to 55,615 genes. Functional coverage in the assembled sequences was 92.0%. About 42.2% of the genome was in exact 20-nucleotide oligomer repeats, and most of the transposons were in the intergenic regions between genes. Although 80.6% of predicted Arabidopsis thaliana genes had a homolog in rice, only 49.4% of predicted rice genes had a homolog in A. thaliana. The large proportion of rice genes with no recognizable homologs is due to a gradient in the GC content of rice coding sequences.

Arabidopsis↗
PubMed2002

Cloning of the mouse Sef gene and comparative analysis of its expression with Fgf8 and Spry2 during embryogenesis.

We report the cloning and expression analysis of a mouse gene encoding a novel transmembrane protein. Expression of Sef is similar to that of Fgf8 and Spry2 during early embryogenesis, being prominent in the forebrain, mid-hindbrain boundary, branchial arches, somites, limb bud and tailbud of mouse embryos. These expression profiles indicate that Fgf8, Spry2 and Sef belong to a synexpression group and suggest that these genes may functionally interact during embryonic development. From E12.5 onwards, partially distinct patterns of expression of these genes are observed in the neuroepithelium, sense organs and endodermal-derived organs, that are known sites of expression of other Fgfs.

Adaptor Proteins, Signal Transducing↗
PubMed2002

Sef is a feedback-induced antagonist of Ras/MAPK-mediated FGF signalling.

Fibroblast growth factors (FGFs) are pleiotrophic growth factors that control cell proliferation, migration, differentiation and embryonic patterning. During early zebrafish embryonic development, FGFs regulate dorsoventral patterning by controlling ventral bone morphogenetic protein (BMP) expression. FGFs function by binding and activating high-affinity tyrosine kinase receptors. FGF activity is negatively regulated by members of the Sprouty family, which antagonize Ras signalling induced by receptor tyrosine kinases. On the basis of similarities in their expression patterns during embryonic development, we have identified five genes that define a synexpression group -- fgf8, fgf3, sprouty2, sprouty4, as well as a novel gene, sef (similar expression to fgf genes). Sef encodes a conserved putative transmembrane protein that shares sequence similarities with the intracellular domain of the interleukin 17 receptor. Here we show that in zebrafish, Sef functions as a feedback-induced antagonist of Ras/Raf/MEK/MAPK-mediated FGF signalling.

Amino Acid Sequence↗
PubMed2002

SOFTDOCK: understanding of molecular recognition through a systematic docking study.

Molecular recognition and docking are essential to the biological functions of proteins. SOFTDOCK was one of the first molecular docking methods developed for protein-protein docking. Its ability to represent the molecular surface with different shapes and properties and to dock a variety of molecular complexes with certain conformational changes was demonstrated in a previous study. In the present work, we studied the effects of the docking parameters through statistical analysis. Seventy one typical binary complexes of different categories in PDB were also systematically docked for a test; 57 of them produced correct solutions with one set of docking parameters whereas the other 14 complexes required adjustment of the docking parameters, by decreasing the softness of the recognition and hence the background noise. We found that these 14 complexes had special structural features. Our results suggest that a variety of mechanisms may be involved in molecular recognition rather than the shape complementarity only, which is very helpful in developing more powerful methods for predicting molecular recognition.

Binding Sites↗
PubMed2002

The pathway of bone fluid flow as defined by in vivo intramedullary pressure and streaming potential measurements.

The pathway for intracortical fluid flow response to a step-load was identified in vivo using intramedullary pressure (ImP) and streaming potential (SP) measurements, and allowed the development of a load-induced flow mechanism which considers mechanotransduction and mechanoelectrotransduction phenomena. An avian model was used for monitoring, simultaneously, ImP and SP under axial loading which generated peak strains of approximately 600 microstrain (microepsilon). ImP response to step-load decayed more quickly than SP relaxation, in which multiple time constants were observed during the relaxations. While the initial relaxation of SP showed a decay on the order of 200 ms, ImP decayed on the order of approximately 100 ms. After the initial decay (approximately 200 ms after loading), ImP quickly relaxed to base line, while SP continued to dominate relaxation. It appears that the decay of ImP is indicative of resistive fluid flow occurring primarily in the vasculature and other intraosseous channels such as lacunar-canalicular pores, and that SP represents the fluid flow in the smaller porosities, i.e., lacunar-canalicular system or even microspores. These results suggest that SP and ImP decays are determined by a hierarchical interdependent system of multiple porosities, and that the temporal dynamics of load-bearing define the manner in which the fluid patterns and pressures are distributed.

Animals↗
PubMed2002

Quantity and quality of trabecular bone in the femur are enhanced by a strongly anabolic, noninvasive mechanical intervention.

The skeleton's sensitivity to mechanical stimuli represents a critical determinant of bone mass and morphology. We have proposed that the extremely low level (< 10 microstrain), high frequency (20-50 Hz) mechanical strains, continually present during even subtle activities such as standing are as important to defining the skeleton as the larger strains typically associated with vigorous activity (>2000 microstrain). If these low-level strains are indeed anabolic, then this sensitivity could serve as the basis for a biomechanically based intervention for osteoporosis. To evaluate this hypothesis, the hindlimbs of adult female sheep were stimulated for 20 minutes/day using a noninvasive 0.3g vertical oscillation sufficient to induce approximately 5 microstrain on the cortex of the tibia. After 1 year of stimulation, the physical properties of 10-mm cubes of trabecular bone from the distal femoral condyle of experimental animals (n = 8) were compared with controls (n = 9), as evaluated using microcomputed tomography (microCT) scanning and materials testing. Bone mineral content (BMC) was 10.6% greater (p < 0.05), and the trabecular number (Tb.N) was 8.3% higher in the experimental animals (p < 0.01), and trabecular spacing decreased by 11.3% (p < 0.01), indicating that bone quantity was increased both by the creation of new trabeculae and the thickening of existing trabeculae. The trabecular bone pattern factor (TBPf) decreased 24.2% (p < 0.03), indicating trabecular morphology adapting from rod shape to plate shape. Significant increases in stiffness and strength were observed in the longitudinal direction (12.1% and 26.7%, respectively; both, p < 0.05), indicating that the adaptation occurred primarily in the plane of weightbearing. These results show that extremely low level mechanical stimuli improve both the quantity and the quality of trabecular bone. That these deformations are several orders of magnitude below those peak strains which arise during vigorous activity indicates that this biomechanically based signal may serve as an effective intervention for osteoporosis.

Animals↗
PubMed2002

[An experimental study on protective effects of Schwann cell cooperation with ECM gel to neurons in rat dorsal root ganglion].

OBJECTIVE: To research the protective effect of Schwann cell and extracellular matrix (ECM) gel on neurons in dorsal root ganglion. METHODS: 1. Schwann cells were seeded into 30% ECM at 1 x 10(8)/ml and then implanted into PLA hollow fiber conduits to repair 10 mm length defects of rat sciatic nerve, and histological observation was taken at 8 and 12 weeks after operation. 2. To observe the survival of Schwann cells, Schwann cells labeled BrdU were seeded into 30% ECM at 1 x 10(8)/ml and then implanted into PLA hollow fiber conduits to repair 10 mm length defects of rat sciatic nerve. Histological observation and immunohistochemical method stained with BrdU were done at 3 and 6 weeks after operation. RESULTS: 1. When seeded into ECM gel and transplanted into rats, most of the Schwann cells survived to 3 weeks and a part of them survived up to 6 weeks. 2. The survival neuron ratios of Schwann cells with ECM gel group and ECM gel group were 83.5% and 81.3% respectively, and significantly higher than that of saline group (72.9%, P < 0.05). CONCLUSION: When seeded into ECM gel and transplanted into rats, most of the Schwann cells survive and protect 83.5% neurons in dorsal root ganglion from retrograde death.

Animals↗
PubMedDate not supplied

Hymeniacidon perleve associated bioactive bacterium pseudomonas sp. NJ6-3-1.

Among the marine bacteria isolated from cytotoxic sponge Hymeniacidon perleve, one strain NJ6-3-1 classified as Pseudomonas sp. showed both cytotoxic and antimicrobial activities. Fatty acid analysis indicated that the bacterial strain consists mainly of C16:1, C16:0, C18:1, C18:0, C15:0, C14:0. One unusual 9,10-cyclopropane-C17:0 fatty acid, and C26:0 also constitute as major component as well as the existence of squalene, the precursor of triterpenoids. The major metabolites in the culture broth were identified as alkaloids, including diketopiperazines and indole compounds, namely 3,6-diisopropylpiperazin-2,5-dione, 3-benzyl-3-isopropylpiperazin-2,5-dione, 3,6-bis-(2-methylpropyl)-piperazin-2,5-dione, indole-3-carboxaldehyde, indole-3-caroxylic acid methyl ester, indole-3-ethanol, and quinazoline-2,4-dione.

Animals↗