Insulin-like Growth Factor Binding Protein Expression in SH-SY5Y Neuroblastoma Cells

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75524/1/j.1749-6632.1993.tb26228.x.pd

Effects of insulin-like growth factor-1 on retinal endothelial cell glucose transport and proliferation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65813/1/j.1471-4159.2001.00325.x.pd

Insulin-like growth factor-I expression is not increased in the retina of diabetic BB/W-rats

A combination of immunocytochemistry, in situ hybridization and ligand binding were used to investigate the localization of IGF-I and its receptor in the retina of diabetic and non-diabetic BB/W-rats. Immunocytochemical localization revealed the presence of IGF-I in retinal pigment epithelium, ganglion cells, Muller cell processes and in microvessels. In most sites immunoreactivity was increased in the diabetic retina compared to that of non-diabetic BB/W-rats. In microvessels, however, immunoreactivity was decreased in diabetes. In situ hybridization using an antisense IGF-I riboprobe provided evidence of IGF-I synthesis in all retinal layers with a similar grain density in diabetic and non-diabetic rats. Autoradiographic localization of IGF-I receptors, using [125I]-IGF-I binding, demonstrated a diffuse localization in all retinal layers, with an increase in diabetic animals. These findings suggest that IGF-I synthesis is not altered in the diabetic retina, and that the increased immunoreactivity of IGF-I detectable in the various layers of the retina from diabetic rats may be due to an increased uptake of blood-derived IGF-I suggested by increased receptor density in diabetic rats.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29042/1/0000075.pd

Gene expression of the insulin-like growth factors and their receptors in cultured human retinal pigment epithelial cells

Insulin-like growth factors I and II (IGF I and II) are polypeptides with both growth-promoting and insulin-like metabolic effects16,27. Immunoreactive IGF I is present in the retina14 and both IGF I and II are present in vitreal fluid12. The type I and type II IGF receptors are also localized within the neural retina3,15,20,33. The presence of IGFs and IGF receptors within the eye suggests a possible growth-promoting effect of IGFs on ocular tissues. IGF may enter the eye from the blood or, alternatively, arise from an ocular cell type which synthesizes and secretes IGF. IGF I and II mRNA synthesis in scleral cells13 and IGF I synthesis in rat retina14 suggests endogenous IGF production in the eye. We hypothesized that IGFs and IGF receptors are synthesized by one ocular cell type, the retinal pigment-epithelium (RPE). As a first step in studying IGF production by the RPE, we analyzed expression of the IGF and IGF receptor genes by cultured human RPE cells. Using Northern analysis, RNase protection and reverse-transcriptase polymerase chain reaction (RT-PCR), we found that cultured RPE cells synthesize mRNA for IGF I and the type II IGF receptors.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30318/1/0000720.pd

A Guide to Mathematical Discovery

Introductory Note. Teachers are often told to teach students by the discovery method. As a junior student at George Washington High School, the writer of this article used the discovery method as described here while participating in a Computer Mathematics Curriculum Project sponsored by the National Science Foundation and directed by William Dorn and Ruth Hoffman of the University of Denver. Ian was asked to document his thinking in a diary fashion so that others could see, firsthand, the discovery method at work. Irwin J. Hoffman, George Washington High School, Denver, Colorado.</jats:p