Functional characteristics of light and dark cells]

Comparison of peculiarties attending the structure of mitochondria in the dark and light cells with the results of studying the respiration of condensed, intermediate and orthodoxic mitochondria showed that dark cells containing condensed mitochondria were at the state of rest or specific activity associated with a high level of bioenergetic and biosynthetic processes. Light cells with a preponderant content of intermediate mitochondria are characterized by the state of active specific activity accompanied by a high energy potential, intensified energy expenditure and a reduction of the level of biosynthetic processes. Light cells with a prevalence of orthodoxic mitochondria are characterized by a low level of energy provision and a predominance of the processes of decomposition of structures over their resynthesis.     

Autoradiographic research on the dark and light Purkinje cells in the cerebellum of rats

Intensity of the 3H-sodium acetate and 3H-leucine incorporation into dark and light Purkinje cells of the rat cerebellum was studied. The intensity of incorporation into light Purkinje cells was found to be 1.5 times higher than into the dark ones.     

Electron microscopic and autoradiographic study of the synthesis of RNA in dark and light adrenal cells

The experiments on mice, who were intraperitoneally injected 5-3H-uridine at a dose of 100 microCi/g, have established that dark adrenal cells are distinct in faster incorporation of the labeled precursor and translocation of the newly-synthetized RNA from the nucleus into the cytoplasm, as compared to light cells. RNA synthesis and translocation into the cytoplasm are more intensive in cells of the glomerular zone. In cortical substance cells, as compared to adrenal cells, the newly-synthetized RNA translocation into the cytoplasm and RNA degeneration are accelerated.     

Eosinophilic globule cells in mouse MFH-like sarcomas. Light and electron microscopic studies

Light and electron microscopic observations were made on eosinophilic globule (EG) cells found in 27 subcutaneous malignant fibrous histiocytoma (MFH)-like sarcomas in aged ICR mice. These tumors, which were composed of fibroblast-like cells as the major component, with small numbers of histiocyte-like cells and undifferentiated cells, showed one or more of five growth patterns: storiform, pleomorphic, fascicular, myxoid, and hemangiopericytoma-like. EG cells were interspersed among the tumor cells and were also present in metastatic lesions. They were pleomorphic in shape and contained various numbers of cytoplasmic globules, which were positive with the periodic acid-Schiff reaction and resistant to diastase digestion. Electron microscopic observation revealed that these cells had small finger-like and pseudopodia-like projections, and contained varied numbers of characteristic osmiophilic globules and glycogen particles in the cytoplasm which seemed to become more abundant as the cells differentiated. The osmiophilic globules consisted of a dense homogeneous core and a marginal area rich in small vesicular membranous structures. A small population of EG cells exhibited features suggesting differentiation to fibroblasts; these were characterized by an increased amount of rough endoplasmic reticulum. It is suggested that the EG cell is a neoplastic cell, perhaps derived from a primitive mesenchymal cell, although an inflammatory cell origin is also possible.     

Light and electron microscopic studies of crayfish hemocytes

Using light and electron microscopy, three hemocyte types are described in the hemolymph of the crayfish. The coagulocyte comprises 65% of the total hemocyte number and contains medium-sized cytoplasmic granules, abundant dilated rough endoplasmic reticulum, and a highly developed Golgi complex. It rapidly undergoes cytolysis in vitro and participates in coagulation by releasing the contents of its granules to the hemolymph. The granulocyte comprises 31% of the total hemocyte number and is capable of phagocytosis. It contains large, irregularly shaped cytoplasmic granules, a moderately developed Golgi complex, and moderate amounts of non-dilated rough endoplasmic reticulum. During coagulation in vitro, the cell attaches and spreads onto the substratum; this is followed by a slow intracellular granule breakdown and cytolysis. The amebocyte comprises 4% of the total hemocyte number and it is also capable of phagocytosis. It possesses small cytoplasmic granules, many vacuoles, a moderately developed Golgi complex, and large amounts of smooth endoplasmic reticulum. It is distinguished from the other two cell types by being stable and motile in vitro.     

Flattening Drosophila cells for high-resolution light microscopic studies of mitosis in vitro

Here we briefly review techniques used to flatten cells that otherwise round in culture, so that their division can be more clearly analyzed in vitro by high resolution light microscopy. We then describe an agar overlay procedure for use with isolated Drosophila neuroblasts, which promotes their long-term viability while also allowing for correlative studies of the same cell in the living and fixed state. This same procedure can also be used to obtain high temporal and spatial resolution images of mitosis and cytokinesis in cultured Drosophila Schneider S2 cells, which are a popular model for RNAi studies.     

Light and electron microscopic studies of nucleus-like formations of fragmented oocytes in rat ovary]

Oocytes in ovarian atretic follicles now and then show in their cytoplasm nucleuslike formations. The appearance of those pseudonuclei in the rat is described by light-and electron microscopy. Every pseudonucleus contains one or more Feulgen positive particles, and is surrounded by a membrane on its surface. The pseudonuclei are formed in the course of degeration of the oocyte during 1. und 2. meiotic metaphase from contracted chromosomes, probably with the involvement of the mixoplasma.     

Light microscopic and electron microscopic study of the cells of tissue cultures irradiated with a neodymium laser]

Damage of tissue culture cells (Hela, a human amnion, a primary rat liver culture) caused by the neodymium laser radiation was studied by time-lapse phase-contrast microfilming and electron microscopy. The tested cultures were shown to display different sensitivity and the degree of cell alteration within the same cultures varied considerably. A physical mechanism of cell damage is probably of thermal and shock-wave nature.     

Variable stainability of Purkinje cells]

The author refers about different staining of the Purkinje-cells with luxol-fast-blue, gallocyanin, thionin and toluidin blue, chrom-alum-hematoxylin-phloxin, impregnation according to Palmgren, lithium and iron-hematoxylin, combination of the staining with phloxin and the Palmgren-impregnation and about the different activity on the acid phosphatase. The phenomenon that in the same histological specimen the positive (dark, chromophile) and negative (light, chromophobe) cells are situated beside, is true for normal animals too, but the number of the dark Purkinje cells is conspicuous higher after stress situations (96-h. immobilisation, intermittent hypoxia). This finding interprets the author by the occurence of phospholipids by binding on the granulated endoplasmatic reticulum, but also as a property of the neuroplasm. The author emphasizes that the staining dualism "light -- dark" of the ganglion cells does not refer only to the ganglion cells of the spinal ganglions (et on some epithelial cells), but also on the Purkinje cells.     

Light and electron microscopic studies of the ventricular wall

Summary Electron microscopic data confirm the results gained with rapid Golgi preparations of adult rodent brains that tanycytes occur in clusters along the lateral wall of the third ventricle. The cytoplasmic matrix of these cells is considerably denser than that of typical ependymal cells. They have filaments and microtubules throughout their cytoplasm along with mitochondria and polysomes. At the surface is a compact group of microvilli which suggest that tanycytes might selectively absorb material from the ventricle.The tanycytes are segregated from neuropil by other tanycyte processes, by neighboring ependymal cells and by astrocytes. Yet there are gaps in this sheath. At these points tanycytes either abut upon or surround nonglial components of the neural fabric.Their cytological features and relations with the neuropil suggest that tanycytes selectively absorb material from the ventricle and release it along the basal process, primarily affecting those segments of neurons immediately adjacent to the tanycyte.Supported by: NINDS Grants 5 R01 NS 09001-02 NEUA, 5T01 NB 5309, and GM 00958, and by the Eleanor Roosevelt Cancer Foundation Research Institute.Acknowledgements: This work was initiated in the Anatomy Department of the Harvard Medical School with facilities provided by Prof. S. L. Palay (U.S. Public Health Service Grant No. NB 05591). Dr. R. B. Wuerker kindly and patiently provided the instruction and orientation to electron microscopy. The major portion of the study was completed in the Neurology Department of the University of Utah with the extremely competent, challenging assistance of Dee Lerdahl, Nina Belgarian, Keith Johnson and Lynn Kendricks.     

Interactions between tumor cells and vascular endothelium.-II) Light and electron microscopic studies

Electron microscope technique was used to investigate the passage across the endothelial monolayer by murine tumor lines. After the initial adhesion, cancer cells induce a retraction of endothelium and migrate under vascular intima. Subsequently they spread on basement membrane showing a flattened shape, meanwhile endothelial cells reconstitute the monolayer. The four tumor lines show a similar behaviour being able to induce endothelial retraction and exposure of extracellular matrix and cross through the monolayer. The technique appears useful to study in details this multi-step process.     

Light and electron microscopic studies of intramitochondrial bodies in bovine adrenocortical cells by proteolytic digestion

Summary The nature of the intramitochondrial bodies in bovine adrenocortical cells was investigated both light and electron microscopically, by applying enzymatic digestion on paraffin and epon sections. The result that these bodies were extracted completely either by pepsin or by trypsin strengthened the validity of the previous conclusion that their nature is proteinaceous.This work was supported by a Scientific Research Grant, No. 144017, from the Ministry of Education of Japan to Prof. M. Yasuda     

The structural-functional properties of light and dark hepatoma cells

Morphofunctional analysis of the light and dark solid hepatoma cells of mouse line 22a C3HA and culture of human hepatoma has shown that in both hepatomas the dark cells when compared with the light ones possess increased electronic density of hyaloplasm, and besides the dark cells of solid tumor line have a well-developed endoplasmic reticulum and numerous mitochondria. Both types of cells are able to incorporate labelled RNA and DNA precursors and also to divide themselves mitotically.