David L. Mason

Cytochemical and biochemical identification of lysosomes in cryptococcus neoformans

Normaski optics, fluorescence and electron microscopy were employed to demonstrate the occurrence of lysosomes in capsulated, enzymatically decapsulated, and dewalled cells of a human isolate ofCryptococcus neoformans. Fluorescent studies, using acridine orange as a lysosomal indicator, revealed the presence of variously sized, spherical, reddish-orange fluorescing bodies. Electron microscopy studies demonstrated the presence of acid phosphatase (AP), a lysosome marker enzyme, in single-membrane bound organelles. Lysosomes were removed from dewalled cells and separated by differential centrifugation on ficoll gradients. That fraction indicating the highest assay for AP was centrifuged at high speed, and the resulting pellet was fixed for electron microscopy and stained by the Gomori procedure for AP. Sections of the pellets revealed AP stained vesicles of the same size range as those within intact cells.

Transplantation Immunity in the Sea Anemone Condylactis gigantea

Graft rejection reactions have been observed in a number of invertebrate species’ including several groups of cnidaria.’ However, sea anemones have heretofore proven resistant to attempts at transplantation. This study was designed to develop (a) a method for grafting Condylactis gigantea, an anemone abundantly available in the Florida Keys and the Caribbean and (b) to observe the macroscopic and microscopic events surrounding graft rejection in this species.

Ultrastructural and Immunological methods in diagnostic pathology in a community hospital.

Five unusual tumors and one case of glomerulonephritis were examined by light microscopy, immunochemical methods, and electron microscopy in order to arrive at a correct diagnosis. We propose that these techniques can be used in community hospitals for selected cases in order to classify certain types of tumors, identify the primary site of some metastatic tumors, and help in the precise classification of some autoimmune diseases.