Biomedical subjects

Hua Xu

Publications and source records attributed to Hua Xu.

62 records · Page 4Linked to original sources

PubMed2002

A3 adenosine receptor knockout mice are protected against ischemia- and myoglobinuria-induced renal failure.

A(3) adenosine receptor (AR) activation and inhibition worsen and improve, respectively, renal function after ischemia-reperfusion (I/R) injury in rats. We sought to further characterize the role of A(3) ARs in modulating renal function after either I/R or myoglobinuric renal injury. A(3) knockout mice had significantly lower plasma creatinines compared with C57 controls 24 h after I/R or myoglobinuric renal injury. C57 control mice pretreated with the A(3) AR antagonist [3-ethyl-5-benzyl-2-methyl-4-phenylethynyl-6-phenyl-1,4-(+/-)-dihydropyridine-3,5 dicarboxylate] or agonist [0.125 mg/kg N(6)-(3-iodobenzyl)-N-methyl-5'-carbamoyladenosine (IB-MECA)] demonstrated improved or worsened renal function, respectively, after I/R or myoglobinuric renal injury. Higher doses of IB-MECA were lethal in C57 mice subjected to renal ischemia. H(1) but not H(2) histamine receptor antagonist prevented death in mice pretreated with IB-MECA before renal ischemia. Improvement in renal function was associated with significantly improved renal histology. In conclusion, preischemic A(3) AR activation (0.125 mg/kg IB-MECA) exacerbated renal I/R injury in mice. Mice lacking A(3) ARs or blocking A(3) ARs in wild-type mice resulted in significant renal protection from ischemic or myoglobinuric renal failure.

Acute Kidney Injury↗

PubMed2002

Age-dependent regulation of rat intestinal type IIb sodium-phosphate cotransporter by 1,25-(OH)(2) vitamin D(3).

The current studies were designed to characterize type IIb sodium-inorganic phosphate (P(i)) cotransporter (NaP(i)-IIb) expression and to assess the effect of 1,25-(OH)(2) vitamin D(3) on NaP(i)-IIb gene expression during rat ontogeny. Sodium-dependent P(i) absorption by intestinal brush-border membrane vesicles (BBMVs) decreased with age, and NaP(i)-IIb gene expression also decreased proportionally with age. 1,25-(OH)(2) vitamin D(3) treatment increased intestinal BBMV P(i) absorption by approximately 2.5-fold in suckling rats and by approximately 2.1-fold in adult rats. 1,25-(OH)(2) vitamin D(3) treatment also increased NaP(i)-IIb mRNA abundance by approximately 2-fold in 14-day-old rats but had no effect on mRNA expression in adults. Furthermore, in rat intestinal epithelial (RIE) cells, 1,25-(OH)(2) vitamin D(3) increased NaP(i)-IIb mRNA abundance, an effect that was abolished by actinomycin D. Additionally, human NaP(i)-IIb gene promoter activity in transiently transfected RIE cells showed approximately 1.6-fold increase after 1,25-(OH)(2) vitamin D(3) treatment. In conclusion, we demonstrate that the age-related decrease in intestinal sodium-dependent P(i) absorption correlates with decreased NaP(i)-IIb mRNA expression. Our data also suggest that the effect of 1,25-(OH)(2) vitamin D(3) on NaP(i)-IIb expression is at least partially mediated by gene transcription in suckling rats.

Aging↗

PubMed2002

Caspases promoted DADAG-induced apoptosis in human leukemia HL-60 cells.

AIM: To investigate the roles of caspases in diacetyldianhydrogalactitol (DADAG)-induced apoptosis in human leukemia HL-60 cells. METHODS: Inhibition of proliferation was measured by MTT assay. DADAG-induced apoptosis in HL-60 cells was observed by electron microscopy, flow cytometry, and DNA fragmentation assay. Caspase-3 activity was determined by ApoAlert CPP32 colorimetric assay kit. The cleavage of substrates of caspases was detected by Western blot. RESULTS: DADAG exhibited potent antiproliferative activity and induced apoptosis in HL-60 cells. After treatment with DADAG 8 mg/L for 24 h, caspase-3 activity increased markedly and the cleavage of poly-(ADP-ribose) polymerase (PARP), lamin B, and DFF45 appeared. All of the apoptotic signals were suppressed by z-VAD fmk (a general inhibitor of caspase activities), whereas z-DEVD fmk, a selective inhibitor of caspase-3 activity, only induced partial reversion of the apoptotic effects. CONCLUSION: DADAG induced apoptosis in HL-60 cells by activating caspases. Caspases promoted apoptosis through the cleavage of substrates of PARP, lamin B, and DFF45.

Apoptosis↗

PubMed2002

[Construction of specifically targeted chimeric hepatitis E virus DNA vaccine and its efficacy assessment].

OBJECTIVE: To design chimeric DNA vaccine targeted to antigen-presenting cells (APCs) with enhanced efficacy to induce immunization. METHODS: The plasmid containing the gene encoding cytotoxic T-lymphocyte antigen 4 (CTLA4), a surface molecule on T cells, was directly fused to the gene fragment HEVE2 coding for hepatitis E virus antigen by molecular engineering technology. The plasmid containing HEVE2 gene fragment alone was also constructed to serve as control and transfection of COS-7 cells with the 2 resultant plasmids was performed respectively, followed by assay of the expressions of CTLA4- HEVE2 fusion protein and HEVE2 protein in COS-7 cells by way of Western blotting. BALB/c mice were injected intracutaneously with the DNA vaccine (100 microgram) for 3 times at 2-week intervals, and the titer of anti-HEVE2 total IgG and IgG subclasses were determined by enzyme-linked immunosorbent assay (ELISA). RESULTS: The mammalian expression plasmids of CTLA4-HEVE2 fusion protein or HEVE2 protein alone were cloned. The culture supernants of COS-7 cells transfected with the plasmids showed the production of CTLA4-HEVE2 and HEVE2 proteins, which were secreted in the form of dimers. Mice immunized with pCTLA2-HEVE2 produced high levels of specific anti-HEVE2 total IgG titers with IgG2a, IgG2b and IgG1 subclasses predominant in the serum, approximately 50- to 100-fold higher than those in mice immunized with pHEVE2, whose serum contained predominantly IgG1. CONCLUSION: CTLA4-HEVE2 chimeric vaccine stimulates strong immune responses in mice, making it possible for further exploration into chimeric DNA vaccines that target the antigen to APCs.

Animals↗

PubMed2002

[Apoptosis induced by diacetyldianhydrogalactitol and its mechanism in HL-60 leukemia cells].

AIM: To investigate the apoptosis induced by diacetyldianhydrogalactitol (DADAG) and its mechanism in human HL-60 leukemia cells. METHODS: Inhibition of proliferation was measured by MTT assay. DADAG-induced apoptosis in HL-60 cells was observed by electron microscopy, flow cytometry and DNA fragmentation assay. The levels of Bcl-2 family proteins were detected by Western blotting. Caspase-3 activity was determined by ApoAlert CPP32 colorimetric assay kit. RESULTS: DADAG exhibited potent antiproliferative activity and induced apoptosis in HL-60 cells. After treatment with DADAG 8 micrograms.mL-1 for various times, the Bcl-XL protein level decreased in a time-dependent manner, while the Bad protein level was upregulated. The caspase-3 activity increased markedly after treatment with DADAG for 24 h. The apoptotic signals were suppressed by z-VAD.fmk (a general inhibitor of caspases), whereas z-DEVD.fmk, a selective inhibitor of caspase-3, only induced partial reversion of the apoptotic effects. CONCLUSION: DADAG-induced apoptosis in HL-60 cells required caspase-3 activation and caspase-3 activation was related with Bcl-2 family members.

Antineoplastic Agents↗

PubMed2002

[Pharmacokinetic study of recombinant human acidic fibroblast growth factor in rabbits by skin external use].

AIM: To investigate the pharmacokinetic characteristics of recombinant human acidic fibroblast growth factor (rhaFGF) after external use in rabbits. METHODS: 125I-rhaFGF 180 U.cm-2 was daubed to normal skin and scathed skin in rabbits. The radioactivity and paper chromatography were used to determine the 125I-concentrations and distribution in plasma and organs at different times. RESULTS: The plasma concentration of 125I-rhaFGF increased rapidily, and reach peak plasma level (73.03 pg.mL-1) thirty minutes after administration. Then the concentration of 125I-rhaFGF decreased quickly after thirty minutes, and approached to zero after three hours. Highest radioactivity accumulated in the skin, followed by kidney, lowest in the brain 96 h after administration. CONCLUSION: rhaFGF can not be absorbed from the normal skin, whereas a small amount of rhaFGF can be absorbed through scathed skin. The t1/2 of rhaFGF in plasma was very short. Cumulative effect of rhaFGF was not observed. Absorbed rhaFGF showed high affinity to skin, and can be distributed to skin far from the site of administration.

Administration, Cutaneous↗

PubMed2002

[Study on antiradiation effect of panaxatriol].

OBJECTIVE: To study antiradiation effect of panaxatriol (PT) and to provide an experiment basis for developing relative radiation-resistant skin care products. METHODS: Mice were treated with PT or normal saline (the control group) before X-ray irradiation and were to observe the number of chromosme aberrations killed 3 hours after irradiation. The chromosome samples of bone marrow cells were prepared and chromatid mutation as well as aberrant cells. RESULTS: PT can reduce the frequency of chromatid mutative induced by X-ray. Antiradiation effect was positively correlated with the dose of PT and the duration of drug, and negatively correlated with the dose of X-rays. CONCLUSION: PT has significant antiradiation effect.

Animals↗

PubMedDate not supplied

Chinese NGOs in action against HIV/AIDS.

Chinese non-governmental organizations (NGOs) have played a significant role in the battle against AIDS in the People's Republic of China. This article provides a brief overview of the structure of these organizations, as well as an analysis of their principle accomplishments. Of great significance in this analysis is the fact that Chinese NGOs have effectively dealt with many sensitive health education areas that government authorities have felt reluctant to handle directly. As such, they have provided an indispensable component in the HIV/AIDS prevention and control calculus on the mainland.

Acquired Immunodeficiency Syndrome↗