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Biomedical subjects

Nicholas A Bock

Publications and source records attributed to Nicholas A Bock.

2 recordsLinked to original sources

Multiple-mouse MRI.

Several theoretical parallel-imaging approaches are evaluated that seek to improve the efficiency of an MRI experiment involving multiple small samples, such as mice. The best method for our mouse phenotyping application is chosen in terms of efficiency and ease of implementation, and the approach is demonstrated at 1.5 T on a clinical scanner with an array of four shielded birdcage coils with four parallel receivers. Electronic interactions between the receiver channels in the system are quantified and a novel sensitivity-encoding (SENSE)-like postprocessing method is described to remove the resulting image ghosts. In parallel imaging with a four-coil array, the time required for three-dimensional (3D) high-resolution imaging of four mice is reduced to one-fourth the time that it would take to image the mice sequentially.

Animals↗

Inhibitors of nitric oxide synthase attenuate nerve growth factor-mediated increases in choline acetyltransferase expression in PC12 cells.

NGF can regulate nitric oxide synthase (NOS) expression and nitric oxide (NO) can modulate NGF-mediated neurotrophic responses. To investigate the role of NO in NGF-activated expression of cholinergic phenotype, PC12 cells were treated with either the nonselective NOS inhibitor L-NAME (N (omega)-nitro-L-arginine methylester) or the inducible NOS selective inhibitor MIU (s-methylisothiourea), and the effect on NGF-stimulated ChAT mRNA levels and ChAT specific activity was determined. NGF increased steady-state levels of mRNA and protein for both inducible and constitutive isozymes of NOS in PC12 cells, and led to enhanced NOS activity and NO production. MIU and, to a lesser extent, L-NAME blocked neurite outgrowth in nerve growth factor (NGF)-treated PC12 cells. Both L-NAME and MIU attenuated NGF-mediated increases in choline transferase (ChAT)-specific activity and prevented the increase in expression of ChAT mRNA normally produced by NGF treatment of PC12 cells. The present study indicates that NO may be involved in the modulation of signal transduction pathways by which NGF leads to increased ChAT gene expression in PC12 cells.

Animals↗