Precautions in Use of Intravital Dyes in Man
William H. Sweet
1. Intracranial Tumors
William H. Sweet and Manucher Javid
Vernon H. Mark and William H. Sweet
Late Changes after Carotid Closure, Acute Measurements after Vertebral Closure
Louis Bakay and William H. Sweet
Partition of Copper-64 Versenate in, and Excretion from, the Body
H. James Bagnall, Philippe Benda, Gordon L. Brownell and William H. Sweet
Robert G. Ojemann, Saul Aronow and William H. Sweet
Vernon H. Mark, Judah Folkman, Frank R. Ervin and William Sweet
Philippe Benda, Takesada Mori and William H. Sweet
✓ Specimens of 16 human brain tumors were studied by the indirect fluorescent-antibody technique to reveal the localization of the particular cerebroprotein found in strikingly increased amounts in human glial tumors as well as in the brain of a patient with Tay-Sachs disease. The cerebro-protein fraction named “10B” by Bogoch was found exclusively in reactive astrocytes, both in astrocytomas and in glioblastomas multiforme. Both the cytoplasm and the cell processes fluoresced upon exposure to antiserum to the “10B” proteins of Tay-Sachs disease. Fluorescence of fibrillary astrocytes located in white matter at some distance from a tumor might be related to discrete edematous changes or constitute an early step in the transition of normal glia to reactive or neoplastic astrocytes. There was no such staining of frankly neoplastic cells or of normal ganglion cells.
Philippe Benda, Kuniyuki Someda, Janette Messer and William H. Sweet
✓ Rat glial tumors, induced by weekly injections of N-nitrosomethylurea for 8 months, were plated and propagated in culture. Cells grew as a glial tumor when injected back into various sites in newborn rats, and were then carried for many generations by transplantations from rat to rat or by alternate culture and animal passage. Light, phase, and electron microscopy of the cultured cells showed great variability among the glial types in all the primary tumors, in the cultures grown from them, and in the secondary in vivo tumors grown from the cultures. Many unmistakable stigmata of glia were conserved. Cloned cultures (derived from a single cell) were frozen and stored, and upon thawing resumed growth with their original histological appearance. Tumor lines from these cultured cloned strains showed much more constant growth rates and cell types; two stable lines were carried for many generations: a slow-growing astrocytoma and a faster growing glioblastoma.
The distinctive neural protein called “S-100” was detected in soluble extracts of cultured cells from all five different primary tumors studied and the secondary tumors grown from them. It represented 0.2% to 0.4% of the soluble proteins extracted from the cultures, and was also present in some clonal strains and their derived tumors. One clonal strain after a few hundred generations continues to synthesize S-100. It is concluded that clonally derived cultures of gliomas histologically similar to those in man provide a stable and suitable model in rats for the study of human glia and gliomas.
Henry H. Schmidek, Denis Fohanno, Frank R. Ervin and William H. Sweet
✓ Experiments were carried out to indicate whether discrete brain stimulation would alter the pain threshold in awake squirrel monkeys subjected to pain by application of stepwise increments of current to the tail. It was found that concurrent brain stimulation will either lower the pain threshold (if applied to the central tegmental tract, ventral posteromedial nuclear group, or occasionally the periaqueductal gray matter); appear to elevate the threshold (if applied to the dorsomedial nucleus); transiently elevate the pain threshold followed shortly by a lowered threshold (if applied to the centromedian-parafascicular complex); or consistently elevate the threshold (if applied to the caudate nucleus, septal-preoptic region, or medial geniculate).