Phenotypic plasticity of pheochromocytoma and normal adrenal medullary cells.

Much of the phenotypic plasticity exhibited by pheochromocytoma cells is shown by normal immature chromaffin cells. Considerable plasticity is also retained by human adrenal medullary cells and probably by adrenal medullary cells of other species in adult life. Many of the cells which exhibit this plasticity have or acquire characteristics of SIF cells.

Crystal-like deposits of amyloid in pancreatic islet cell tumors.

Numerous stellate crystal-like deposits of amyloid were observed in four human pancreatic islet cell tumors. Three of the tumors were associated with hypoglycemia or hyperinsulinemia, and the remaining one produced gastrin. Histochemical and ultrastructural studies confirmed the existence of amyloid in the deposits and also suggested the presence of adsorbed or incorporated mucopolysaccharides.

Small cell carcinoma of the lung: cellular origin and relationship to other neoplasms.

Many small cell carcinomas share morphological and physiological characteristics with normal and neoplastic cells of Pearse's APUD series, including pulmonary APUD cells and pulmonary carcinoid tumors. There is very likely more than one type of APUD cell in the lung, and conclusions that small cell carcinomas and carcinoids reflect neoplastic transformation of the same cell type are probably premature. The embryoogic lineage of pulmonary APUD cells is at present uncertain.

Morphologic and cytochemical properties of a clonal line of rat adrenal pheochromocytoma cells which respond to nerve growth factor.

The PC12 pheochromocytoma line is a clonal line derived from a rat adrenal medullary tumor. PC12 cells grown in vitro have morphologic and cytochemical features in common with normal chromaffin cells in varying stages of development, and with human pheochromocytomas. These features include catecholamine stores demonstrable by formaldehyde-induced fluorescence and argentaffinic secretory granules, measuring 30 to 350 nm.

Characterization of the immunochemical forms of calcitonin released by a medullary thyroid carcinoma in tissue culture.

Immunoreactive calcitonin released by a medullary thyroid carcinoma in tissue culture has been found to exhibit heterogeneity when analyzed by gel chromatography and radioimmunoassay, in a pattern analogous to that seen in the circulation of the patient from whom the neoplasm was removed. To examine the cause of the heterogeneity, the immunoreactive material released by the tumor into tissue culture medium was further analyzed by gel electrophoresis in the presence of the protein denaturant 8 M urea, by gel chromatography after reduction and alkylation, by affinity chromatography on concanavalin A-agarose, and by bioassay in a renal adenylyl cyclase system of enhanced sensitivity. The results suggest that the larger immunochemical forms of calcitonin described in the circulation of patients with medullary thyroid carcinoma may be released directly from the neoplasm and need not derive from peripheral metabolism of the monomer.

Inhibition of adenocarcinoma TA3 ascites tumor growth by rifamycin derivatives.

A growth inhibitory effect on adenocarcinoma TA3 ascites tumors in LAF1/J mice resulted from the repeated IP administration of subtoxic doses of 3 rifamycin derivatives: rifampicin (Rif)1, dimethylbenzyldesmethylrifampicin (DMB), and rifazone-82 (R-82). A high-viscosity methylcellulose vehicle was found to be essential for obtaining a uniform drug suspension and a significant antitumor effect by the least water soluble derivatives, DMB and R-82. The more hydrophilic derivative, Rif, was found to have a comparable growth inhibitory effect on TA3 cells when prepared in 0.

Medullary carcinoma of the human thyroid in monolayer culture: morphological and cytochemical correlations.

Mechanically or enzymatically dissociated cells from three human medullary thyroid carcinomas (MTC) were grown in monolayer culture for periods up to seven months. Cultures of each tumor contained clusters of small epithelial-like cells which were readily identified by phase contrast microscopy. Immunocytochemical studies and electron microscopy showed that these cells contained abundant calcitonin and numerous secretory granules.

Electrical excitability of oat cell carcinoma.

Cultured tumour cells from two oat cell carcinomas of the lung were demonstrated to generate all-or-nothing, short-duration action potentials similar to those previously reported in neurones, in bronchial carcinoid cells, and in a number of endocrine cells of proven or proposed neural ancestry. This observation provides new evidence to establish oat cell carcinomas and carcinoids as closely related tumours distinct from other pulmonary neoplasms, and raises the possibility of treating these tumours by manipulation of hormonal agents.

Sodium and calcium action potential in pituitary cells.

Several endocrine cells or their neoplastic derivatives generate action potentials similar to those seen in neurones, and in the adrenal chromaffin cell such regenerative potentials depend primarily on a sodium mechanism. Kidokoro has described action potentials in the GH3 rat pituitary cell line which seem to depend on a calcium mechanism. We have re-investigated the action potential in GH3 cells and found that it results from combined Na and Ca mechanisms in physiological conditions.

Electrical excitability of cultured adrenal chromaffin cells.

1. Adult human and gerbil adrenal medullary cells were maintained in dissociated cell culture and studied by micro-electrode penetration. 2.

Gas-forming clostridial mycotic aneurysm of the abdominal aorta. A case report.

Gas-forming mycotic aneurysms are extremely rare. A case is reported in which rupture of a gas-forming mycotic aneurysm of the distal abdominal aorta due to Clostridium paraputrificum occurred in an elderly male with a myeloproliferative disorder and a necrotic carcinoma of the colon.

Establishment of a noradrenergic clonal line of rat adrenal pheochromocytoma cells which respond to nerve growth factor.

A single cell clonal line which responds reversibly to nerve growth factor (NGF) has been established from a transplantable rat adrenal pheochromocytoma. This line, designated PC12, has a homogeneous and near-diploid chromosome number of 40. By 1 week's exposure to NGF, PC12 cells cease to multiply and begin to extend branching varicose processes similar to those produced by sympathetic neurons in primary cell culture.

Neural properties of cultured human endocrine tumor cells of proposed neural crest origin.

Cells from human endocrine tumors of proposed neural crest origin--five pheochromocytomas, two medullary carcinomas of the thyroid, and two bronchial carcinoids--were grown in monolayer culture. Cells from all nine tumors, including epithelial forms of medullary carcinoma of the thyroid and bronchial carcinoid cells, and epithelial and neuron-like pheochromocytoma cells demonstrated all-or-nothing, short-duration action potentials.

Preferential inhibition of the growth of virus-transformed cells in culture by rifazone-82, a new rifamycin derivative.

Rifazone-8(2), a new rifamycin derivative, is shown to preferentially inhibit the growth of virus-transformed chick cells in culture. Macromolecular synthesis and glucose uptake of transformed cells are also appreciably decreased in the presence of low concentrations of rifazone-8(2) where the normal cells appear unaffected. While rifazone-8(2) is shown to be a selective inhibitor of RNA-directed DNA polymerase in vitro, its action on the growth of transformed cells may involve some other mechanism.

Inhibition of three nucleotide polymerases by rifamycin derivatives.

It is possible to design rifamycin derivatives which can distinguish between viral RNA-instructed DNA polymerase and other nucleotide polymerases.