PubMed · 9880974
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
J L Turkenburg, E L van Persijn van Meerten. 1998. Focal nodular hyperplasia.. https://pubmed.ncbi.nlm.nih.gov/9880974/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Explore the source record for details and available documents.
Dominantly inherited multiple endocrine neoplasia type 2B (MEN2B) is characterized by tumors of the thyroid C-cells and adrenal chromaffin cells, together with ganglioneuromas of the gastrointestinal tract and other developmental abnormalities. Most cases are caused by substitution of threonine for Met918 in the RET receptor tyrosine kinase, which is believed to convert the RET gene to an oncogene by altering the enzyme's substrate specificity. We report the production of a mouse model of MEN2B by introduction of the corresponding mutation into the ret gene. Mutant mice displayed C-cell hyperplasia and chromaffin cell hyperplasia progressing to pheochromocytoma. Homozygotes did not develop gastrointestinal ganglioneuromas, but displayed ganglioneuromas of the adrenal medulla, enlargement of the associated sympathetic ganglia and a male reproductive defect. Surprisingly, homozygotes did not display any developmental defects attributable to a loss-of-function mutation. Thus, while our results support the conclusion that the Met918Thr substitution is responsible for MEN2B, they suggest that the substrate specificity of the RET kinase does not interfere with its normal role in the development of the kidneys and enteric nervous system.
This study investigates the release of Neuropeptide Y from eight human pheochromocytomas. Profil immunoreactive Neuropeptide Y (Ir-NPY) levels during the management of surgery were compared with these of norepinephrine (NE) while hemodynamics were monitored. Plasma IrNPY and NE levels increased during tumor manipulation and returned to near normal one hour after operation. However, Ir-NPY levels remained high just after tumor resection while NE levels were significantly decreased. At tumor manipulation and just after tumor resection, plasma Ir-NPY levels were correlated with the systemic vascular resistances (SVR) (r = 0.74; P<0.04 and r = 0.86; P<0.006 respectively). No correlation was found either between plasma Ir-NPY and NE levels or between plasma NE levels and SVR. The release of Ir-NPY from tumor tissue, studied by a superfusion method, exhibited a significant correlation with the plasma Ir-NPY concentrations at the time of corresponding tumor resection (r = 0.95; P<0.007). Chromatographic analysis showed that Ir-NPY in plasma and outflow migrate as human NPY (1-36). These results confirmed that in pheochromocytoma, plasma NPY mainly originates from the tumor and argue for an important role of NPY in pheochromocytoma hypertension as indicated by the correlation between the Ir-NPY levels and the SVR.