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Biomedical subjects

Q Niu

Publications and source records attributed to Q Niu.

At least 37 records · Page 2Linked to original sources
PubMed1998

[Study on the changes of heart-rate in lead-exposed workers].

ECG examination and questionnaires survey were performed among lead-exposed workers in order to assess whether moderate occupational lead exposure may cause autonomic nervous system (ANS) dysfunction. The tests included; 1. heart-rate response to Valsalva manoeuvre (HR-V); 2. heart-rate variation during deep breathing (HR-DB); 3. immediate heart-rate response to immediate stand up (30:15 or Max:Min). The results did not show any evidence that lead exposure is related to ANS dysfunction. There was no significant difference between the exposed workers and controls who were with the same ages (P > 0.05). The important cause for ANS dysfunction was aging.

Adult↗
PubMed1996

CD40L is important for induction of, but not response to, costimulatory activity. ICAM-1 as the second costimulatory molecule rapidly up-regulated by CD40L.

The CD40 ligand (CD40L):CD40 interaction plays an important role in the activation of both T and B cells. However, the mechanisms by which this interaction is involved in activation of T cells is still unclear. Here we show that CD40L is not essential for T cell response to TCR engagement if the APC have costimulatory activity, although it is essential for T cell-mediated induction of such costimulatory activity. To determine the molecular basis of this activity, we have produced three mAbs that appear to recognize the costimulatory molecules rapidly induced by CD40L. Two of them recognize CD44H, which we showed to have CD28-independent costimulatory activity for T cells. The molecule recognized by the remaining mAb is hereby identified as ICAM-1. Furthermore, ICAM-1-mediated costimulation is likely to serve for a function similar to that mediated by the B7:CD28 interaction, as targeted mutation of CD28 renders T cell responses to Con A more dependent on ICAM-1.

Animals↗
PubMed1996

Formation of Atomically Flat Silver Films on GaAs with a "Silver Mean" Quasi Periodicity

A flat epitaxial silver film on a gallium arsenide [GaAs(110)] surface was synthesized in a two-step process. Deposition of a critical thickness of silver at low temperature led to the formation of a dense nanocluster film. Upon annealing, all atoms rearranged themselves into an atomically flat film. This silver film has a close-packed (111) structure modulated by a "silver mean" quasi-periodic sequence. The ability to grow such epitaxial overlayers of metals on semiconductors enables the testing of theoretical models and provides a connection between metal and semiconductor technologies.

Journal Article↗
PubMed1995

Structure and expression of a smooth muscle cell-specific gene, SM22 alpha.

SM22 alpha is expressed exclusively in smooth muscle-containing tissues of adult animals and is one of the earliest markers of differentiated smooth muscle cells (SMCs). To examine the molecular mechanisms that regulate SMC-specific gene expression, we have isolated and structurally characterized the murine SM22 alpha gene. SM22 alpha is a 6.2-kilobase single copy gene composed of five exons. SM22 alpha mRNA is expressed at high levels in the aorta, uterus, lung, and intestine, and in primary cultures of rat aortic SMCs, and the SMC line, A7r5. In contrast to genes encoding SMC contractile proteins, SM22 alpha gene expression is not decreased in proliferating SMCs. Transient transfection experiments demonstrated that 441 base pairs of SM22 alpha 5'-flanking sequence was necessary and sufficient to program high level transcription of a luciferase reporter gene in both primary rat aortic SMCs and A7r5 cells. DNA sequence analyses revealed that the 441-base pair promoter contains two CArG/SRF boxes, a CACC box, and one potential MEF-2 binding site, cis-acting elements which are each important regulators of striated muscle transcription. Taken together, these studies have identified the murine SM22 alpha promoter as an excellent model system for studies of developmentally regulated, lineage-specific gene expression in SMCs.

Amino Acid Sequence↗