scholarly journals AN ELECTRON MICROSCOPE STUDY OF THE EMBRYOLOGY OF THE INTERCALATED DISC IN THE HEART OF THE RABBIT

1957 ◽  
Vol 3 (2) ◽  
pp. 193-202 ◽  
Author(s):  
Alan R. Muir
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Cardiac Muscle ◽  
Microscope Study ◽  
Light Microscope ◽  
Electron Microscope Study ◽  
Muscle Cells ◽  
Intercalated Disc ◽  
Adult Cell ◽  
Embryonic Muscle

Prenatal and postnatal cardiac muscle from rabbits has been studied by electron microscopy, after osmium fixation and methacrylate embedding. The observations showed that 1. Cell membranes divide the muscle into cellular units from the youngest embryo which was studied (9½ days after coitus) until the adult state. 2. The embryonic muscle cells contain only one nucleus, whereas the adult cell may be multinucleated. 3. At all stages of development, wherever a myofibrillar axis crosses a cellular boundary, the myofilaments are interrupted by an intercalated disc. 4. With age, increase in size and complexity of the discs render them recognisable by the light microscope.

scholarly journals An Electron Microscope Study of Basophile Substances of Frozen-Dried Rat Liver

1958 ◽  
Vol 4 (3) ◽  
pp. 291-300 ◽  
Author(s):  
Henry Finck
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Rat Liver ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Freeze Drying ◽  
Light And Electron Microscopy ◽  
Enzyme Treatment ◽  
Dense Granules ◽  
Homogeneous Matrix

Small pieces of liver from rats subjected to different dietary regimes were fixed by freeze-drying, and postfixed by in vacuo heating and denaturation with alcohol. Specimens were digested with ribo- or deoxyribonuclease, and stained with gallocyanin-chromalum, azure II, the Feulgen procedure or alcoholic platinic tetrabromide. Some specimens were reserved as controls of the effects of enzyme treatment. Stained and unstained specimens were embedded in methacrylate and examined by light and electron microscopy. Basophilic and Feulgen-positive substances, after contact with watery reagents, were found by electron microscopy to exist as small dense granules embedded in a less dense homogeneous matrix, forming the walls of submicroscopic vacuoles. These granules were absent after digestion with nucleodepolymerases. In specimens (unstained, or stained with platinic tetrabromide) which had not passed through water, the dense (basophile) substances in nuclei and cytoplasm were found to exist, not as granules, but as ill defined submicroscopic concentrates which blended imperceptibly into the homogeneous matrix of the vacuolar walls. Objections to the use of stains for improving contrast conditions in electron microscopy of tissues are discussed, and it is concluded that the reagents do not necessarily produce the observed increases in contrast by selectively stabilizing certain structures. The concept of microsomes as pre-existing distinct morphological entities in intact (unhomogenized) cells is thought to be inconsistent with the distribution of basophile substances in frozen-dried liver.

scholarly journals ELECTRON MICROSCOPY OF THE NUCLEAR MEMBRANE OF AMOEBA PROTEUS

1956 ◽  
Vol 2 (4) ◽  
pp. 445-448 ◽  
Author(s):  
Marie H. Greider ◽  
Wencel J. Kostir ◽  
Walter J. Frajola
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Nuclear Membrane ◽  
Outer Layer ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Cell Types ◽  
Amoeba Proteus ◽  
Nuclear Membranes ◽  
Thin Sectioning

An electron microscope study of the nuclear membrane of Amoeba proteus by thin sectioning techniques has revealed an ultrastructure in the outer layer of the membrane that is homologous to the pores and annuli observed in the nuclear membranes of many other cell types studied by these techniques. An inner honeycombed layer apparently unique to Amoeba proteus is also described.

scholarly journals An Electron Microscope Study of the Source and Distribution of Ferritin in Hepatic Parenchymal Cells of the Newborn Rabbit

Blood ◽  
1960 ◽  
Vol 15 (4) ◽  
pp. 480-490 ◽  
Author(s):  
JAMES C. HAMPTON
Keyword(s):  
Electron Microscope ◽  
Microscope Study ◽  
Light Microscope ◽  
Electron Microscope Study ◽  
Hepatic Cell ◽  
Cell Cytoplasm ◽  
Electron Microscopic ◽  
Newborn Rabbit ◽  
Blue Reaction ◽  
Parenchymal Cells

Abstract Evidence that erythrocytes are phagocytized and dismantled by hepatic parenchymal cells in the newborn rabbit is presented. It is concluded that in these cells iron is recovered from disintegrating erythrocytes, synthesized into ferritin and released into the hepatic cell cytoplasm and into the biliary passages. These conclusions are based upon observations on the distribution of material giving the Prussian blue reaction in sections of liver as revealed by the light microscope and upon electron microscopic images of particles displaying the size, density and configuration of the ferritin molecule.

An electron-microscope study of peristerite plagioclases

1965 ◽  
Vol 35 (269) ◽  
pp. 165-176 ◽  
Author(s):  
S. G. Fleet ◽  
P. H. Ribbe
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Electron Diffraction ◽  
Microscope Study ◽  
Lamellar Structure ◽  
Electron Microscope Study ◽  
Transmission Electron

SummaryPlagioclase feldspars in the peristerite range An2-An17 have been investigated by transmission electron-microscopy and electron diffraction. All except the more anorthite-rich specimens were found to be unmixed into albite and oligoclase lamellae, between a few hundred and several thousand Å thick and approximately parallel to . A discussion is given of the part played by these lamellae when optical schiller is exhibited; and the effect of heat treatment on the lamellar structure and optical schiller is described.

scholarly journals AN ELECTRON MICROSCOPE STUDY OF SALIVARY GLAND CHROMOSOMES BY THE REPLICA METHOD

1949 ◽  
Vol 89 (4) ◽  
pp. 431-438 ◽  
Author(s):  
Sanford L. Palay ◽  
Albert Claude
Keyword(s):  
Electron Microscopy ◽  
Salivary Gland ◽  
Electron Microscope ◽  
Nucleic Acid ◽  
Electron Micrographs ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Amorphous Material ◽  
Desoxyribonucleic Acid ◽  
Linear Network

A method for preparing replicas of salivary gland chromosomes for electron microscopy is described. Electron micrographs of these replicas show that the giant chromosomes are composed of a series of small granules of approximately equal size arranged transversely across the chromosome. In stretched preparations a linear network of filaments appears between the rows of granules. These fibers cannot be traced between corresponding granules of more than two consecutive rows. When the chromosomes are digested by desoxyribonuclease, these fibers disappear and only amorphous material remains between the bands. The characteristics of the strands suggest that they are artifacts produced when the chromosomes are stretched. The small granules are composed of desoxyribonucleic acid and at least one other component, probably a protein. The nucleic acid seems to lie at least in part on the surface of each granule.

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