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Bondareff, William; Tuttle, Richard L.
doi: 10.1002/aja.1001440302pmid: 1211367
RGC‐6 cells, grown to confluency in monolayer cultures, are typically fusiform. In sections of these cells, fixed in situ and examined in the electron microscope, a discontinuous zone of cortical cytoplasm (5–7 nm wide), was found subjacent to the plasma membrane of the free surface. It was composed largely of 5–7 nm microfilaments distributed in an apparently irregular nework and appeared to comprise a discrete zone separating the plasma membrane from the underlying endoplasm.
doi: 10.1002/aja.1001440303pmid: 1211368
The embryonic development of the rat carotid body was studied with electron microscopy. In the 11 mm embryo a cell aggregation consisting of undifferentiated cells and unmyelinated nerve fibers appears on the anterior wall of the third branchial artery. Granule‐containing cells appear in the 12 mm embryo and continue to increase in number as the cellular aggregation increases in size and becomes separated from the wall of the third branchial artery. Synapse formation and the appearance of fenestrated capillaries occur almost simultaneously at the 17 mm stage. There are two types of synapses, one with membrane densification and vesicles clustered inside the nerve endings, the other with dense material and vesicles inside the granule‐containing cells. At the 20 mm stage the undifferentiated cells send enveloping cytoplasmic processes toward adjacent granule‐containing cells and the carotid body anlage displays rudimentary lobules.
Grisham, J. W.; Nopanitaya, W.; Compagno, J.; Nägel, A. E. H.
doi: 10.1002/aja.1001440304pmid: 1211369
Scanning electron microscopy (SEM) allows the surface ultrastructure of intrahepatic cells and other tissue components of liver to be delineated. Excellent depth of focus of the SEM makes it possible to visualize surfaces of intact cells in their native configurations. This report details the surface characteristics and inter‐relationships of hepatocytes and hepatic plates, sinusoidal endothelial cells and sinusoids, presumed Kupffer cells, vessels, bile ducts, connective tissue, and the capsule of rat liver. Hepatocytes present three structurally distinctive faces – the intercellular face containing flat surfaces and bile canaliculus, the sinusoidal face, and the connective tissue face which abuts portal tracts and hepatic veins. Sinusoidal endothelium is penetrated by large (1 to 3 μm) and small (0.1 μm) fenestrae, the latter occurring in clusters of up to 50. The width of bile canaliculi and distribution of large fenestrae vary proximodistally along hepatic plate or sinusoid. The cells of portal bile ductules contain microvilli located in linear rows and sparse cilia. Endothelium of hepatic artery and of portal vein is sparsely fenestrated.
doi: 10.1002/aja.1001440305pmid: 55069
The occurrence of intracellular fibrillar material (frequently banded) has been studied in normal costal and tracheal chondrocytes of rats at various ages ranging from 1 to 90 days. The study methods have included digestion with collagenase, electron histochemical techniques and routine electron microscopy.
Steven, William M.; Snook, Theodore
doi: 10.1002/aja.1001440306pmid: 55070
The effects of the estrogenic compounds, diethylstilbestrol (DS) and diethylstilbestrol diphosphate (DSP) on morphologically demonstrable characteristics of reticuloendothelial (RE) cells were studied in rat spleen. These included metalophilia, acid phosphatase, nonspecific esterase and phagocytosis. Routine histological and histochemical techniques were used to determine the distribution of metalophilic cells, hydrolytic enzymes, the presence of intracytoplasmic PAS‐positive material, hemosiderin sequestration, and the ability to phagocytose injected carbon particles and bacterial organisms.
Swartz, William J.; Schuetz, Allen W.
doi: 10.1002/aja.1001440309pmid: 1211371
This study was designed to classify and differentiate the population of oocytes released from the mouse ovary by mechanical means. Liberated oocytes were classified on the basis of their number, size and by the nature of the attachment of follicle cells to these oocytes. Microscopical examination of oocytes mechanically released from the ovaries revealed three distinct morphological classifications of oocytes: (1) those completely devoid of follicle cells, (2) those encased in follicle cells and (3) those in the process of degeneration. Oocytes ranged in size from approximately 30μ to 119μ. Those oocytes surrounded by follicle cells could be further subdivided into two groups depending on whether the follicle cells could be mechanically removed from the oocyte. These data demonstrate that the adult ovary contains a variety of classes of oocytes which differ in size and in the extent to which the follicle cells are attached to the oocytes. It is suggested that the metabolic activities and meiotic potentials of the various oocyte populations differ and as a result, care should be employed to insure a uniform population of oocytes when conducting further studies with mechanically liberated oocytes.
Nyberg, Leroy M.; Marks, Sandy C.
doi: 10.1002/aja.1001440310pmid: 1211372
Calvarial bone from osteopetrotic (ia) rats and normal littermates has been cultured in a chemically defined medium supplemented with homologous serum to test for the presence of inhibitors or the absence of promoters of bone resorption in mutant serum. In addition, the response of mutant and normal bone to parathyroid extract and hydrocortisone was tested in vitro. The results indicate that mutant and normal serum do not differ with respect to their ability to support bone resorption and that ia bone responds to hydrocortisone but not parathyroid extract in organ culture. These data indicate that the skeletal defect in ia rats is not humoral but cellular.
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