Biomedical subjects

Webster H Pilcher

Publications and source records attributed to Webster H Pilcher.

2 recordsLinked to original sources

PubMed2006

Complementary patterns of gene expression by human oligodendrocyte progenitors and their environment predict determinants of progenitor maintenance and differentiation.

OBJECTIVE: Glial progenitor cells are abundant in adult human white matter. This study was designed to identify signaling pathways regulating their self-renewal and fate. METHODS: We compared the transcriptional profiles of freshly sorted adult human white matter progenitor cells (WMPCs), purified by A2B5-based immunomagnetic sorting, with those of the white matter from which they derived. RESULTS: We identified 132 genes differentially expressed by WMPCs; these included principal components of five receptor-defined signaling pathways, represented by platelet derived growth factor receptor alpha (PDGFRA) and type 3 fibroblast growth factor receptor (FGFR3), receptor tyrosine phosphatase-beta/zeta (RTPZ), notch, and syndecan3. WMPCs also differentially expressed the bone morphogenetic protein 4 (BMP4) inhibitors neuralin and BAMBI (BMP and activin membrane-bound inhibitor), suggesting tonic defense against BMP signaling. Differential overexpression of RTPZ was accompanied by that of its modulators pleiotrophin, NrCAM, tenascin, and the chondroitin sulfate proteoglycans, suggesting the importance of RTPZ signaling to WMPCs. When exposed to the RTPZ inhibitor bpV(phen), or lentiviral-shRNAi against RTPZ, WMPCs differentiated as oligodendrocytes. Conversely, when neuralin and BAMBI were antagonized by BMP4, astrocytic differentiation was induced, which was reversible by noggin. INTERPRETATION: The RTPZ and BMP pathways regulate the self-maintenance of adult human WMPCs, and can be modulated to induce their oligodendrocytic or astrocytic differentiation. As such, they provide targets by which to productively mobilize resident progenitor cells of the adult human brain.

Adolescent↗

PubMed2004

Axial loading during MR imaging can influence treatment decision for symptomatic spinal stenosis.

BACKGROUND AND PURPOSE: Previous studies have shown that axial loading can narrow the spinal canal. However, the clinical significance is unclear. The purpose of this study was to determine whether the narrowing of the spinal canal with axial loading during MR imaging could influence treatment decision for spinal stenosis. METHODS: Two hundred patients with clinical symptoms of spinal stenosis underwent routine MR imaging and then immediately underwent axially loaded MR imaging. We selected 20 of these patients because they had narrowing of the spinal canal shown on the axially loaded images. Three experienced neurosurgeons evaluated these 20 patients based on clinical information and routine MR images. The same neurosurgeons were then asked for second treatment decisions based on the same clinical information but with axially loaded MR images. RESULTS: Axial loading during MR imaging of the lumbar spine can influence neurosurgeons in their treatment decisions for symptomatic spinal stenosis. For this selected group of patients, all three neurosurgeons changed their treatment decision from conservative management to decompressive surgery for five patients when shown the axially loaded MR images. For two other patients, two neurosurgeons changed their treatment decisions, and for three additional patients, one neurosurgeon changed his treatment decision, all based on the axially loaded MR images. Treatment was not changed from surgical to medical management for any of the patients when shown the axially loaded images. CONCLUSION: In selected patients with spinal stenosis and apparent narrowing of the spinal canal shown by axially loaded MR imaging, the additional information gained from this technique can influence experienced neurosurgeons in their treatment decisions.

Adult↗