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Biomedical subjects

Fang Xia

Publications and source records attributed to Fang Xia.

23 records · Page 2Linked to original sources

Effect of methylprednisolone on reperfusion injury in severe uncontrolled hemorrhagic shock.

OBJECTIVE: To study the effect of methylprednisolone (MP) on reperfusion injury in severe uncontrolled hemorrhagic shock and explore the possible mechanism involved. METHODS: Twelve dogs were randomly divided into two groups, control group (Group I, n=6) and MP group (Group II, n=6). The animals were bled continuously from a femoral artery catheter to produce uncontrolled hemorrhagic shock models. Resuscitation with lactated Ringer's (LR) solution was initiated when mean arterial pressure (MAP) decreased to 20 mm Hg, and MAP was maintained at 30-40 mm Hg. MP (4 mg/kg) was injected intravenously in Group II when resuscitation began. While in Group I, normal saline (NS) was injected instead. The levels of superoxide dismutase (SOD) and malondialdehyde (MDA) were measured before exsanguination (T(1)), when MAP decreased to 20 mm Hg (T(2)), 60 min (T(3)) and 120 min (T(4)) after resuscitation. Heart rate, MAP and cardiac output (CO) levels were recorded concomitantly. RESULTS: Infusion volume and hemorrhage volume shed from the superior mesenteric artery in Group I were higher than those in Group II (P<0.01 and P<0.05). After reperfusion, blood SOD levels decreased progressively and MDA levels increased rapidly in Group I. In Group II, blood SOD levels at T(3) and T(4) decreased as compared with that at T(1) but a stepwise increase was present. At T(4), blood SOD level was significantly higher in Group II than in Group I (Plt;0.01). At T(3) and T(4), MDA levels were markedly lower in Group II than in Group I. During reperfusion, MAP was more steady in Group II than in Group I and survival rate after 120 min (at T(4)) was higher in Group II than in Group I (P<0.05). CONCLUSIONS: MP has a protective effect on severe uncontrolled hemorrhagic shock and subsequent reperfusion injury. The mechanism mainly involves the anti-lipid peroxidation activity of MP.

Analysis of Variance↗

Regulation of androgen receptor activity by the nuclear receptor corepressor SMRT.

Androgen receptor (AR) is a hormone-regulated transcription factor that mediates a wide array of biological processes including sexual differentiation, spermatogenesis, and prostate cancer progression. The transcriptional activity of AR and other members of the nuclear receptor superfamily are modulated by coregulatory proteins. In this study, we have investigated the regulation of AR transcriptional activity by the silencing mediator for retinoid and thyroid hormone receptors (SMRT). We found that AR possesses an intrinsic transcriptional repression activity, and AR interacts directly with SMRT. One interacting surface on AR is mapped to the ligand-binding domain, and the presence of a DNA binding/hinge region enhances this interaction. The binding surface on SMRT is mapped to the C-terminal ID2 region, and mutation in the ID2 corepressor motif inhibits the interaction. Overexpression of SMRT inhibits dihydrotestosterone-dependent transactivation by AR and further suppresses the antiandrogen flutamide-mediated inhibition of AR activity. We provide evidence to suggest that the mechanisms of SMRT-mediated inhibition of AR activity involves inhibition of AR N/C interaction and competition with the p160 coactivator. Our data establish a significant role of SMRT in modulating AR transcriptional activity.

DNA-Binding Proteins↗

Cloning and expression pattern of a spermatogenesis-related gene, BEX1, mapped to chromosome Xq22.

Through screening a human fetal brain cDNA library, a cDNA similar to the mouse Bex1 was isolated. This new gene was named brain expressed X-linked protein 1 (BEX1). Northern blot analysis revealed a 1.0 kb transcript highly expressed in brain, pancreas, testis, and ovary, with lower levels present in heart, placenta, liver, kidney, spleen, thymus, prostate, small intestine, colon (no mucus), thyroid, spinal cord, and adrenal gland. No hybridization signal was seen in lung, skeletal muscle, peripheral blood leukocyte, stomach, lymph node, trachea, and bone marrow. The BEX1 gene was localized to chromosome band Xq22 between markers between DXS990 and DXS1059 by screening Stanford radiation hybrid G3 panels. In situ hybridization of mouse testis using BEX1 as a probe detected the signal in the pachytene spermatocytes and spermatids but not in spermatogonia. Furthermore, it was not detected at 6, 9, and 12 days postpartum, was present in low amount on Days 15 and 18 and its expression increased sharply after the initiation of puberty (about 21 days) in mouse testis.

Amino Acid Sequence↗

[Expression of cell adhesion molecules in acute leukemia cell].

OBJECTIVE: To investigate the role of cell adhesion molecule in the development and extramedullary infiltration (EI) of acute leukemia. METHODS: The expressions of neural cell adhesion molecule (NCAM) gene, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule (VCAM-1) genes in 25 acute leukemia patients bone marrow cells were detected by microarray and reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: The expressions of NCAM, ICAM-1 and VCAM-1 gene were significantly higher in acute leukemia cells and leukemia cells with EI than in normal tissues and leukemia cells without EI, respectively, both by cDNA microarray and by RT-PCR. CONCLUSION: The cDNA microarray is a powerful technique in analysis of acute leukemia cells associated genes. High expressions of cell adhesion molecule genes might be correlated with leukemia pathogenesis and infiltration of acute leukemia cell.

Acute Disease↗