Epidermal growth factor binding sites in the mouse exocrine and endocrine pancreas shown by in vivo quantitative microautoradiography and confocal laser scanning microscopy.

Microautoradiography at 3, 6 and 15 min after intravenous injection of 125I-EGF was used to investigate the distribution of epidermal growth factor (EGF) binding sites in the pancreas of normal male mice. The autoradiographs were observed by confocal laser microscopy, which allows the quantification of silver grains. The results demonstrated that both endocrine and exocrine pancreatic cells exhibited substantial specific binding of 125I-EGF. The highest level of EGF binding was found in the duct cells of the exocrine pancreas followed by the acinar cells. The cells of the islets of Langerhans also showed substantial specific binding of 125I-EGF though the binding level was lower than that of the exocrine pancreas. In the control experiments, mice were injected with 125I-EGF and various amounts of unlabeled EGF.

Measurement of distensibility of blood vessels using cineangiograms.

We developed a new, cineangiographic method to accurately measure the dynamic changes in the internal diameter of human arteries in vivo. Cine films were digitized at a spatial resolution of 4 microns/pixel, using a line image sensor. The vessel edges, with a Gaussian fit to a unilateral profile curve of the vessel, were determined with the aid of a computer program. We measured contrast-filled cylinder vessel models (2 to 7 mm in diameter) and evaluated precision, accuracy and linearity of the diameter measurement. A pulsatile vessel model of about 3.9 mm in internal diameter was used to examine the reliability of our method for detecting arterial wall motion. If the coefficient of variation of the vessel diameter determined cineangiographically was less than 2.2% we considered the cineangiograms sufficiently accurate to determine the internal vessel diameter and evaluate arterial distensibility.