Biomedical subjects

Ming Guan

Publications and source records attributed to Ming Guan.

23 records · Page 2Linked to original sources

PubMed2003

Decreased pigment epithelium-derived factor and increased vascular endothelial growth factor levels in pterygia.

PURPOSE: Pterygia are histologically composed of proliferating fibrovascular tissue. This study compared expression levels of an angiogenic inhibitor, pigment epithelium-derived factor (PEDF), in pterygia with those in normal corneal and conjunctival tissues. METHODS: The normal human conjunctival and corneal tissues were obtained from surgery or from donor eyes without ocular diseases. Pterygia were excised by therapeutic surgery under a microscope. Pigment epithelium-derived factor and vascular endothelial growth factor (VEGF) were measured by Western blot analysis. Their cellular localizations were determined by immunohistochemistry. RESULTS: Intensive PEDF immunostaining was detected in all the normal corneal and conjunctival samples analyzed, predominantly in the epithelium and endothelium of the cornea and in the epithelium of the limbus and conjunctiva. Under the same immunostaining conditions, pterygial samples showed negative or faint PEDF staining. In contrast, the same pterygial samples all showed intensive VEGF staining, predominantly in the epithelium and in blood vessels. Western blot analysis confirmed that the average PEDF level in pterygia was drastically lower than those in normal corneal and conjunctival tissues, respectively. In contrast, the VEGF level in pterygia was significantly higher than in the normal tissues. CONCLUSION: Pterygia exhibit significantly lower PEDF but higher VEGF levels than those in normal corneas and conjunctivae. The decreased PEDF level in pterygia may play a role in the formation and progression of pterygia.

Case-Control Studies↗

PubMed2003

[Changes of alkaline phosphatase sugar chains in hepatocellular carcinoma tissue].

OBJECTIVE: To investigate the changes of sugar chain structures of alkaline phosphatase (ALP) in hepatoma tissue and its relation to the invasiveness of hepatocellular carcinoma (HCC). METHODS: The binding ratios of ALP from 9 normal liver tissues, 16 hepatoma tissues and 16 noncancerous tissues surrounding hepatoma were analysed by affinity chromatography on various lectin columns including leukoagglutinating phytohemagglutinin (L-PHA), lentil lectin (LCA), Datura stramonium agglutinin (DSA), erythroagglutinating phytohemagglutinin (E-PHA) and Sambucus nigra bark agglutinin (SNA). RESULTS: The binding ratios of ALP on L-PHA (22.94%+/-5.30%), DSA (55.97%+/-13.72%), LCA (38.16%+/-8.87%), E-PHA (11.56%+/-4.81%) and SNA (69.80%+/-13.71%) in HCC tissues were significantly increased (P<0.01) compared with that in normal liver tissues (L-PHA 5.89%+/-2.75%, DSA 36.20%+/-11.58%, LCA 17.90%+/-6.71%, E-PHA 5.38%+/-2.20%, SNA 57.32%+/-11.27%), respectively. t values between the two groups were 8.94, 3.64, 5.94, 3.62 and 2.32, respectively. L-PHA-binding ratio (25.84%+/-4.67%) of ALP in HCC with invasiveness was significantly higher than that (18.10%+/-3.64%) without invasiveness (t=3.71, P<0.01). CONCLUSION: The changes of ALP sugar chain structures occur in HCC tissue. b1-6 branching sugar chain structure of ALP is related to the invasiveness of HCC.

Alkaline Phosphatase↗

PubMed2002

Tissue factor expression and angiogenesis in human glioma.

BACKGROUND: Tissue factor (TF), a cell surface receptor of factor VII/VIIa, was initially recognized as an initiator of the extrinsic coagulation pathway. TF has recently been found to be expressed highly in certain types of malignant tumors. In addition, TF expression appears to be a marker for malignant angiogenesis in human solid tumors. However TF expression and its relationship to angiogenesis and tumor progression in human glioma are still unclear. METHODS: Quantitative reverse transcription PCR and immunofluorescence were performed on the U251 glioma cell line, 5 normal brain specimens, and 34 glioma surgical specimens. Of the gliomas, 10 were grade IV, 12 grade III, 7 grade II, and 5 grade I. Microvessels were highlighted using a monoclonal antibody specific to human von Willebrand factor. RESULTS: TF was strongly positive in 90% of the grade IV cases, 58% of grade III, 43% of grade II, and 20% of grade I. TF staining was not present in any normal brain specimens. The mean level of TF mRNA in normal brain tissue was 5.0 x 10(3) copies/microg RNA. Among the gliomas, TF mRNA ranged from 1.7 x 10(5) to 6.8 x 10(7) copies/microg, with a mean of 4.6 x 10(6). TF expression was highest in glioblastomas that showed greatest vascularity. CONCLUSIONS: These findings support a role for TF in angiogenesis in glioma. TF is expressed in glioma and the level of expression correlates with the histologic grade of malignancy and vascularity.

Antigens↗

PubMed2002

Production of extracellular domain of human tissue factor using maltose-binding protein fusion system.

Making use of the physiological process of coagulation as an anti-tumor effector function may be beneficial in various coagulation-mediated diseases. Preclinical and clinical studies with novel tissue factor targeting constructs require that efficient procedures for preparing large quantities of pure truncated TF (tTF) become available. In this study, we described a simple and rapid on-column method for purifying large quantities of human tTF from Escherichia coli. The coding region of extracellular domain of tissue factor was linked to the 3(')-end of maltose-binding protein (MBP) gene. The fusion protein was expressed as soluble form after induction by isopropylthio-beta-D-galactoside (IPTG). MBP-tTF was purified by amylose affinity chromatography. MBP can be removed by digestion with factor Xa. Expression could represent 21.5% of the total soluble protein in E. coli, allowing approximately 15mg of highly purified protein to be obtained per liter of bacterial culture. The fusion protein was recognized in Western blot by anti-TF monoclonal antibody and the activity was confirmed by chromogenic assay. This MBP-fusion system permits large-scale functional expression and purification of recombinant soluble proteins, providing a basis for the future study of structure and function of tTF.

Blotting, Western↗

PubMed2002

Quantitative reverse transcription-PCR measurement of tissue factor mRNA in glioma.

BACKGROUND: Initiation of the coagulation serine protease cascade in mammalian cells is mediated by tissue factor (TF), which is a cell surface receptor and cofactor for coagulation factor VII (FVII) and its activated form FVII (FVIIa). Increasing evidence suggests that TF is expressed in a wide range of cancer cells and plays important roles in cancer progression and metastasis. In this study, we investigated the association between the expression level of TF transcript and histologic features of glioma. METHODS: RNA was extracted from normal brain tissues and glioma tissues. We developed and validated a real-time quantitative reverse transcription (RT)-PCR assay, based on fluorescent TaqMan methodology, to quantify TF gene expression and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) at the mRNA level in human glioma. RESULTS: The dynamic range of the assay was 10(3)-10(8) copy/microg RNA. The relationship between Ct and log starting concentration was linear (r2 > or = 0.99). The mean expression of TF in healthy brain tissue was 6.2 x 10(3) copy/microg RNA. Overexpression of TF was found in 42 brain glioma samples, mean value is 2.9 x 10(6) copy/microg RNA. CONCLUSIONS: TF mRNA transcript is expressed in glioma and the level of expression correlates with histologic grade of malignancy. This new simple, rapid, semiautomated assay is a major alternative to Northern blot and competitive quantitative PCR for gene alteration analysis in human tumors and may be a powerful tool for large randomized, prospective cooperative group trials and support future TF-based clinical applications.

Biomarkers, Tumor↗