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Biomedical subjects

Ai-Hua Zhang

Publications and source records attributed to Ai-Hua Zhang.

8 recordsLinked to original sources
PubMed2006

Inhibition of oxidation activity of myeloperoxidase (MPO) by propylthiouracil (PTU) and anti-MPO antibodies from patients with PTU-induced vasculitis.

Propylthiouracil (PTU) could induce antineutrophil cytoplasmic antibody (ANCA) associated vasculitis. This study aimed to investigate the inhibitory effects on MPO oxidation activity by PTU and MPO-ANCA from patients with primary microscopic polyangiitis (MPA) and PTU-induced vasculitis. IgG preparations were purified from MPO-ANCA-positive sera from seven patients with PTU-induced vasculitis and ten patients with primary MPA. The oxidation activity of MPO was measured in the presence of PTU and MPO-ANCA-positive IgG preparations from patients with PTU-induced vasculitis and primary MPA respectively. PTU could competitively inhibit the oxidation activity of MPO dose dependently. MPO-ANCA-positive IgG preparations from 6/7 patients with PTU-induced vasculitis and only 3/10 from patients with primary MPA could inhibit the MPO activity in a dose-dependent manner. In conclusions, the oxidation activity of MPO could be inhibited by PTU and PTU-induced MPO-ANCA in a dose-dependent manner, which might be involved in the pathogenesis PTU-induced vasculitis.

Adult↗
PubMed2005

Theoretical electron energy-loss spectroscopy and its application in materials research.

Electron energy-loss near-edge fine structure (ELNES) of group-III nitrides is calculated using a pseudopotential plan wave method within the framework of density functional theory. Core-hole effect and supercell size influence are investigated. Based on our present and earlier work, a comprehensive understanding of theoretical ELNES application in materials research is demonstrated: interpreting experimental spectra, predicating theoretical reference spectra when reliable experimental spectra are not available, identifying ELNES-structure correlation and estimating the reliability of experimental spectra.

Journal Article↗
PubMed2004

Transfection of p27kip1 enhances radiosensitivity induced by 60Co gamma-irradiation in hepatocellular carcinoma HepG2 cell line.

AIM: To study the cell cycle alterations of human hepatoma cell line HepG(2) in vitro after (60)Co gamma-irradiation and further to examine the mechanisms underlying the enhancement of radiosensitivity to gamma-irradiation in HepG(2) transiently transfected with wild type p27(kip1). METHODS: The proliferation of HepG(2) cells was evaluated with MTT assay, and the cell cycle profile and apoptosis were assessed by cell morphology, DNA fragmentation analysis and flow cytometry. HepG(2) cells were transfected with p27(kip1) wild type by using Lipofectamine (LF2000), and the expression and subcellular localization of p27(kip1) in HepG(2) were detected by immunocytochemistry. RESULTS: (60)Co gamma-irradiation inhibited the growth of HepG(2) cells in a dose-dependent manner. Apoptosis of HepG(2) cells was induced 48 h after gamma ray exposure. Furthermore research was carried out to induce exogenous expression of p27(kip1) in HepG(2). The expression of p27(kip1) induced G(0)/G(1) phase arrest in HepG(2) cells. The overexpression of p27(kip1) enhanced (60)Co gamma-irradiation-induced radiosensitivity in HepG(2) cells. CONCLUSION: Overexpression of p27(kip1) is a rational approach to improve conventional radiotherapy outcomes, which may be a possible strategy for human hepatoma therapy.

Apoptosis↗
PubMed2004

[Effect of curcumin on extracellular matrix accumulation in the glomeruli in nephrotoxic sera nephritis rats].

OBJECTIVE: To observe whether curcumin could inhibit the accumulation of the collagen IV and fibronectin in the glomeruli in nephrotoxi sera nephritis rats. METHODS: Seventy-two healthy male Sprague-Dawley rats were divided into three groups, with 24 animals in each group. For normal control group, normal saline (0.5 ml/d) was injected through intra-caudal-vein for two days, and at the same time normal saline (0.5 ml/kg) was also daily administered intraperitoneally. For nephrotoxic sera nephritis group, nephrotoxic sera (0.5 ml/d) was injected through the tail vein for two days and dimethyl sulfoxide (0.5 ml/kg) was given intraperitoneally daily. For curcumin group, nephrotoxic sera was injected as above and meanwhile curcumin (50 mg.kg(-1).d(-1)) was administered intraperitoneally every day. Six rats in each group were killed on the 3rd, 7th, 14th and 28th day. Their renal tissue was fixed in 10% formalin for examining the expression of collagen IV and fibronectin. RESULTS: Minimal staining of collagen IV and fibronectin was detected in the basement membrane of normal control rats glomeruli. In the nephrotoxic sera nephritis rats and curcumin treated nephrotoxic sera nephritis rats, the accumulation of collagen IV and fibronectin was increased progressively, with significant difference in the accumulation of collagen IV (P<0.01) between these two groups at the same time points, while the significant difference in fibronectin accumulation (P<0.05) appeared only after the 7th days. CONCLUSION: Curcumin can reduce the accumulation of collagen IV and fibronectin in the glomeruli. Hence we postulated that curcumin might have beneficial effect for retarding glomerulosclerosis.

Animals↗
PubMed2004

[Induction of monocyte chemoattractant protein-1 expression in human mesangial cells by angiotensin II: role of c-Jun N-terminal kinase-c-Jun/activator protein-1 signal pathway].

OBJECTIVE: To investigate the role of c-Jun N-terminal kinase (JNK)-c-Jun/activator protein-1 (AP-1) signal pathway in expression of monocyte chemoattractant protein-1 (MCP-1) in experimental rat glomerulonephritis. METHODS: Nephrotoxic sera nephritis (NTN) was induced by injection of anti-GBM antibody into the tail veins of rats. Electrophoretic mobility shift assay (EMSA) and non-radioactive kinase assay were used to detect the activity of AP-1 and JNK in kidneys and angiotensin II-stimulated human mesangial cells. Ribonuclear protection assay was used to detect MCP-1 expression in cultured human mesangial cells. RESULTS: Significant up-regulation of JNK and AP-1 was observed in NTN rats (3.82 +/- 0.58) folds and (5.36 +/- 0.61) folds, as compared with the controls. Supershift assay demonstrated that c-Jun and c-Fos were the predominant subunits involved. Activation of JNK and AP-1 significantly correlated with MCP-1 expression in NTN rats. Angiotensin II enhanced the expression of MCP-1 and activation of JNK and AP-1 in cultured human mesangial cells in a dose-dependent manner, with maximal stimulation seen at 100 nmol/L (20.99 +/- 4.71) folds, (6.91 +/- 1.65) folds and (7.82 +/- 1.32) folds respectively. Significant down-regulation of AP-1 activation and MCP-1 expression were observed in angiotensin II-induced human mesangial cells pretreated with JNK specific inhibitor SP600125. CONCLUSIONS: Angiotensin II and MCP-1 may play an important role in glomerulosclerosis via the JNK-c-Jun/AP-1 signal pathway.

Angiotensin II↗
PubMed2003

Molecular pathology of skin carcinogenesis due to arsenicalism from coal-burning.

Arsenicalism has been observed throughout the world and has become an urgent public health concern. The authors explored the mechanism of carcinogenesis of inorganic arsenic in patients with arsenicalism from coal-burning pollution. The 68 subjects were divided into 3 groups--carcinoma, precarcinoma, and common-on the basis of pathological diagnosis. The expressions of proliferating cell nuclear antigen (PCNA), mutant-type P53, and B-cell lymphoma/leukemia-2 (BCL-2) proteins were detected by immunohistochemical staining. PCNA, P53, and BCL-2 proteins were overexpressed. The proteins' overexpressions correlated with the pathological changes seen in each pathological study group (i.e., common < precarcinoma < carcinoma). Statistical correlation was observed between P53 and BCL-2, and between PCNA and BCL-2. The authors concluded that cell proliferation, antiapoptosis, and up-regulation of the mutant-type P53 gene played vital roles in the pathological development of arsenicalism.

Arsenic↗
PubMed2002

Molecular cloning and sequence analysis of heavy- and light-chain variable region genes of anti-CD71 monoclonal antibody.

OBJECTIVE: To clone heavy-chain and light-chain variable region (VH and VL) gene of mouse-anti-human CD71 monoclonal antibody (mAb). METHOD: One-step method was used to extract total RNA, and a set of oligonucleotide primers were designed to amplify the cDNAs with reverse transcriptase-polymerase chain reaction (RT-PCR), and the resultant products were respectively cloned into PMD18-T vector and their sequences analyzed. RESULTS: The PCR product obtained with the oligonucleotide primers for the variable region of mouse immunoglobulin heavy chain was about 350 bp and that with oligonucleotide primers for the light chain was about 320 bp, and their DNA sequences were determined. CONCLUSION: The length of the cloned heavy chain variable region was 348 bp, belonging to mouse heavy-chain subgroup II(A); the light-chain variable region was 336 bp that belongs to mouse kappa light-chain subgroup II.

Amino Acid Sequence↗