Showing papers by "Janet E. Price published in 1992"

Differential permeability of the blood-brain barrier in experimental brain metastases produced by human neoplasms implanted into nude mice.

Abstract: This study clarified whether and when the blood-brain barrier in experimental brain metastases is impaired by using hydrosoluble sodium fluorescein (MW 376) as a blood-brain barrier function indicator. Cells from eight human tumor lines (four melanomas, two breast carcinomas, one colon carcinoma, and one renal carcinoma) were inoculated into the internal carotid artery of nude mice. Brain metastases at different stages of development were sampled and the permeability of the blood-brain barrier around the metastases determined. Histologic examination showed two patterns of tumor growth. In the first, tumor cells formed isolated, well-defined nodules in the parenchyma of the brain. In lesions smaller than 0.2 mm2, the blood-brain barrier was intact. In the second, small diffuse nests of tumor cells were distributed throughout the brain parenchyma. The blood-brain barrier was intact until the small tumor cell colonies coalesced to form large tumor masses. These results suggest that the permeability of the blood-brain barrier varies among different experimental brain metastases and that its function is related to the growth pattern and size of the lesions.

Basement membrane collagen-IV synthesis in colorectal tumours

Abstract: Many studies suggest that increased proteolysis accounts for the epithelial basement membrane (EBM) breaks commonly seen in carcinomas. As failure to produce or maintain EBM may also be important, we chose to investigate synthesis of basement membrane collagen-IV in human colorectal carcinomas. First, to determine the cellular origin of EBM collagen-IV, species-specific antibodies were used to analyse caecal xenografts of 4 different human colorectal-carcinoma-derived cell lines. The results of this study suggest an exclusively stromal cell origin for EBM collagen-IV. Next, the distribution of periglandular myofibroblasts in carcinomas was examined, since in normal mucosa their location and ultrastructural features suggest that they play a role in EBM maintenance. They were generally abundant in normal mucosa and adenomas, but sparsely distributed in carcinomas, particularly at the invasive periphery where EBM collagen-IV immunostaining is most deficient. Finally, the in situ hybridization technique was used to define cell populations synthesizing collagen-IV. In normal mucosa, no collagen-IV mRNA was detected in any component, while in carcinomas, the mRNA was clearly detectable in vascular endothelial cells but not in any other cell type. Increased vascular collagen-IV production in carcinomas may be at least partly due to tumour-induced angiogenesis, since new blood-vessel formation requires the synthesis of new vascular basement membranes.

Einfluß der Leberregeneration auf das biologische Verhalten menschlicher Tumormetastasen in der thymuslosen Nacktmaus

Abstract: Die ausgepragte Regenerationsfahigkeit der Leber ist ein Prozes, der durch unbekannte Faktoren im Pfortaderblut ausgelost wird, in eine massive, kurz anhaltende Proliferationswelle mundet und einer prazisen zeitlichen Steuerung unterliegt.