Non-linear shrinkage of Batson's #17 resin during vascular corrosion casting.

Many studies of cardiovascular function require a realistic representation of vascular geometry. Corrosion casting has been used to acquire such geometries for many decades. However, the fidelity with which this method reproduces vascular anatomy has not been completely determined. Here we report on the non-linear shrinkage characteristics and exothermic properties of Batson's #17, a widely used casting resin, in model systems and in aortas of rats and rabbits. The setting process was captured using high-resolution photography. Shrinkage ranged from 3.4 ± 1.5% of the diameter in 1 ml plastic syringes (inner diameter 4.8 mm) to 19.6 ± 5.6% in the aorta of rats (diameter 1.5-2.6 mm). In addition, aortic curvature and branching angles changed during setting. These effects should be determined and corrected in studies of vascular geometry where high accuracy is required.

Implantation of c-mycER TAM immortalized human mesencephalic-derived clonal cell lines ameliorates behavior dysfunction in a rat model of Parkinson's disease.

Human neural stem cells offer the hope that a cell therapy treatment for Parkinson's disease (PD) could be made widely available. In this study, we describe two clonal human neural cell lines, derived from two different 10-week-old fetal mesencephalic tissues and immortalized with the c-mycER(TAM) transgene. Under the growth control of 4-hydroxytamoxifen, both cell lines display stable long-term growth in culture with a normal karyotype. In vitro, these nestin-positive cells are able to differentiate into tyrosine hydroxylase (TH)-positive neurons and are multipotential. Implantation of the undifferentiated cells into the 6-OHDA substantia nigral lesioned rat model displayed sustained improvements in a number of behavioral tests compared with noncell-implanted, vehicle-injected controls over the course of 6 months. Histological analysis of the brains showed survival of the implanted cells but no evidence of differentiation into TH-positive neurons. An average increase of approximately 26% in host TH immunoreactivity in the lesioned dorsal striatum was observed in the cell-treated groups compared to controls, with no difference in loss of TH cell bodies in the lesioned substantia nigra. Further analysis of the cell lines identified a number of expressed trophic factors, providing a plausible explanation for the effects observed in vivo. The exact mechanisms by which the implanted human neural cell lines provide behavioral improvements in the PD model are not completely understood; however, these findings provide evidence that cell therapy can be a potent treatment for PD acting through a mechanism independent of dopaminergic neuronal cell replacement.