Biomedical subjects

H J Liu

Publications and source records attributed to H J Liu.

93 records · Page 6Linked to original sources

PubMedDate not supplied

Interleukin-11 enhancement of VLA-5 mediated adhesion of CD34+ cells from cord blood to fibronectin is associated with the PI-3 kinase pathway.

Adhesion is required for cell growth, differentiation, survival, and function. Cell adhesion is mediated by a structurally diverse group of plasma membrane receptors, each exhibiting specialized ligand-binding properties that are needed for specific tasks. Integrin-mediated adhesion is important for hematopoietic stem (HSC)/progenitor (HPC) cell survival and may prevent programmed cell death. Interleukin (IL)-11, a multi-functional cytokine secreted by the bone marrow environment, plays an important role in regulating growth and differentiation of HSCs/HPCs. In this report, we demonstrate that IL-11 enhanced adhesion of freshly isolated and 3 day-expanded CD34+ cells to immobilized fibronectin. the expression of very late antigen (VLA)-4 and VLA-5 integrins was detected on CD34+ cells. CD34+ cells also expressed a-chain and gp130 subunits of the IL-11 receptor (R). Enhanced adhesion by IL-11 was mediated via activation of VLA-5 integrins, since this action could be blocked by monoclonal antibodies against beta 1 and alpha 5, but not alpha 4, integrins. Addition of phosphatidylinositol (PI)-3 kinase inhibitors blocked IL-11 enhanced adhesion of CD34+ cells to fibronectin. The results suggest that this enhanced adhesion is associated with the PI-3 kinase pathway, an inside-out signaling pathway.

Antibodies, Blocking↗

PubMedDate not supplied

Characterization of a nonradioactive cloned cDNA probe for detecting avian reoviruses.

Avian reoviruses (ARVs) cause important losses in the poultry industry. Improved tests are needed for diagnosis of ARV infections. A cDNA library was prepared from the S1133 isolate of ARV. EcoRI-adaptored cDNA molecules were ligated into the plasmid pUC19 and used to transform Escherichia coli strain DH5 alpha MCR. One cDNA clone was selected and designated HJp1. The HJp1 was labeled by random priming with digoxigenin-dUTP. This cDNA probe hybridized with the S1 gene fragment of the ARV S1133 strain in northern blot hybridization. The probe detected ARV isolates in dot-blot hybridization assays. The probe did not cross-hybridize with nucleic acids extracted from mock-infected chicken embryo fibroblast cells or unrelated avian viruses. Probe HJp1 detected as little as 0.78 ng of ARV RNA.

Animals↗

PubMedDate not supplied

In situ detection of reovirus in formalin-fixed, paraffin-embedded chicken tissues using a digoxigenin-labeled cDNA probe.

An in situ hybridization (ISH) technique using a digoxigenin (DIG)-labeled cDNA probe detected avian reovirus (ARV) RNA in formalin-fixed, paraffin-embedded chicken tissues. Tissues were collected 3 and 10 days following inoculation with the R-2 or the S1133 strain of ARV. The cDNA clone HJp1, located on the S1 gene segment of the ARV S1133 strain, was used to prepare a nonradioactive probe. The ISH assay localized ARV RNA in infected tissues including heart, liver, intestine, pancreas, and tendon. No positive-stained cells occurred in sections from uninfected chickens.

Animals↗