A previously uncharacterized type of sickled cell was found in venous blood ofpatients with sickle cell disease when blood was collected without exposure to air and fixed immediately with 1% glutaraldehyde solution equilibrated with 5% oxygen. These cells were either elongated, resembling irreversibly sickled cells (ISCs), or nonelongated, with a raisinlike shape. Both types assumed a normal discoidal shape upon full oxygenation. Since these cells exist only under partially oxygenated conditions, they are described as partially oxygenated sickled cells (POSCs). POSCs are morphologically distinct from partially deoxygenated sickled cells formed during deoxygenation by having rounded edges, while the latter have sharp edges. Transmission electron microscopy of POSCs revealed various amounts of misaligned Hb S polymers. Investigations in vitro demonstrated the formation of POSC-like cells by partial oxygenation of deoxygenated cells. Since POSCs contain intracellular fibers and sickle readily upon deoxygenation, they may have clinical and pathological significance.Sickle cell disease was so named because of the abnormal morphology of red blood cells (RBCs) observed by microscopic examination offixed and stained blood smears obtained from affected patients (1). Subsequently, relationships were found between oxygen and RBC sickling (2) and between intracellular polymerization of abnormal hemoglobin and cell deformation (3-5). Demonstration of sickling of RBCs from patients with sickle cell disease (SS cells) in vitro is highly dependent upon the method of deoxygenation. For example, classic sickle-or crescent-shaped cells are formed after slow deoxygenation (6-9), whereas SS cells with a granular or mosaic appearance result from rapid deoxygenation with nitrogen (6) or sodium dithionite (7). These differences may be explained by the number and size of domains of polymerized Hb S formed in the cells (10). During morphologic studies of SS cells, we noticed that the number and shape of sickled cells in venous blood were altered by the oxygenation of blood during and after blood collection. To avoid postcollection artifacts, we developed a method to collect blood under venous oxygen pressure without exposure to air. This enabled us to discover two additional types of reversibly sickled cells, elongated sickled cells with a shape like irreversibly sickled cells (ISCs) and shrunken cells with a raisin-like appearance. Since these cells exist only under partially oxygenated conditions, they are described as partially oxygenated sickled cells (POSCs) (11). We report our investigation of the morphologic properties and analysis by electron microscopy ofintracellular polymers of POSCs found in venous blood of patients with sickle cell disease. MATERIALS AND METHODSPreparation of Blood Samples. To minimize sickling during blood drawing (12), blood was drawn from the antecubital vein after release of the tourniquet. A conventional 5-ml plastic disposable syringe was used by the technique similar to that used for collectio...

After exposure of permissive cells to simian virus 40 (SV40), single particles were engulfed by the cell membrane and transported to the nucleus. The cell membrane closed tightly around the particles, increasing their diameter from 40 to 55 nm. The cell membrane was lost during interaction with the nuclear membranes, and particles of the original size were found in the nucleus 1 hr after infection. Uncoating of these nuclear particles occurred rapidly, and none could be found 4 hr after infection; Viral progeny appeared 24 hr after infection.

In a preceding report (1) we described a method which permitted detailed investigation of the fine structure of antibody-producing ceils obtained from lymph nodes. These cells, from rabbits injected with sheep erythrocytes, were recognized by the hemolytic plaques which they produced on incubation with the target erythrocytes in vitro. Such plaques were removed for study of the central cell by electron microscopy. We found that cells in the category both of lymphocytes and of plasma cells could produce antibodies of the 19S type after a single injection of the antigen. The lymphocytic cells showed an increase in structures presumably associated with synthetic functions, such as endoplasmie reticulum, Golgi body, and nueleolus, not present in the quiescent small lymphocyte. The gradations of organelle development through a series of cells which included lymphocytic and plasmacytic forms suggested that in the lymph node the antibody-producing cells underwent a progression of development leading from the small lymphocyte to the mature plasma cell, with a great variety of intermediate stages. Of these cell types some, of the plasmacyfic series, have been identified in other electron microscopic studies of antibody-forming lymph node cells by Bussard and Binet (2), and by Fitch, Rowley, and Coulthard (3).The antibody-producing cells in our earlier study (1) were obtained from the lymph node by teasing the excised organ, and thus might not represent the ceils which under physiological conditions would pass into the efferent lymph and eventually into the peripheral blood. These extranodal antibody-producing cells could represent the most highly organized types, with respect to their fine structure, since they were presumably fully developed in the lymph node before leaving it to enter the efferent lymph vessel. Such cells, obtained from efferent lymph, the thoracic duct, and peripheral blood were investigated and the results are presented.