scholarly journals ADENOSINE TRIPHOSPHATASE LOCALIZATION IN AMPHIBIAN EPIDERMIS

1966 ◽  
Vol 30 (2) ◽  
pp. 359-379 ◽  
Author(s):  
Marilyn G. Farquhar ◽  
George E. Palade
Keyword(s):  
Cell Membranes ◽  
Light And Electron Microscopy ◽  
Salient Feature ◽  
Cell Junctions ◽  
Intercellular Spaces ◽  
Amphibian Skin ◽  
Fixed Tissue ◽  
Outer Leaflet ◽  
Transport Atpases ◽  
Distal Aspect

The localization of ATPase1 activity has been studied by light and electron microscopy in the epidermis of Rana pipiens, Rana catesbiana, and Bufo marinus. The reaction was carried out on skin (glutaraldehyde-fixed or fresh) sectioned with or without freezing. Best results were obtained with nonfrozen sections of fixed tissue. The incubation mixture was either a Wachstein-Meisel medium, or a modification which approximates assay systems used in biochemical studies of transport ATPases. The reaction product was found localized in contact with the outer leaflet of all cell membranes facing the labyrinth of intercellular spaces of the epidermis. It was absent from: (a) membrane areas involved in cell junctions (desmosomes, zonulae and maculae occludentes); (b) cell membranes facing the external medium (i.e., those on the distal aspect of the ultimate cell layer in s. corneum); (c) cell membranes facing the dermis (those on the proximal aspect of cells in s. germinativum). In the presence of (Na+ + K+) the localization did not change, but the reaction was not appreciably activated. A similar though less intense reaction was obtained with ITP, but not with ADP, AMP, and GP as substrates. The results are discussed in relation to available data on transport ATPases in general, and on the morphology and physiology of amphibian skin in particular. Assuming that the ATPase studied is related to transport ATPase, the findings suggest a series of modifications to the frog skin model proposed by Koefoed-Johnsen and Ussing. The salient feature of this modified model is the localization of the Na+ pump along all cell membranes facing the intercellular spaces of the epidermis.

scholarly journals LOCALIZATION OF ADENOSINE TRIPHOSPHATASE ACTIVITY IN PRENEOPLASTIC AND CANCEROUS CELLS OF THE MOUSE SKIN INDUCED BY METHYLCHOLANTHRENE

1968 ◽  
Vol 16 (11) ◽  
pp. 678-687 ◽  
Author(s):  
JÁNOS SUGÁR ◽  
ORSOLYA CSUKA ◽  
JÓZSEF TÓTH
Keyword(s):  
Adenosine Triphosphatase ◽  
Cell Membranes ◽  
Light And Electron Microscopy ◽  
Mouse Skin ◽  
Intercellular Spaces ◽  
Adenosine Triphosphatase Activity ◽  
Dense Deposits ◽  
Membrane Bound ◽  
Cancerous Cells ◽  
Normal Epidermis

The localization of membrane-bound adenosine triphosphatase activity has been studied by both light and electron microscopy in the normal epidermis and in methylcholanthreneinduced preneoplastic alterations, i.e., hyperplasia, papilloma and also in similarly induced cancers of the skin of mice. In normal epidermis, the adenosine triphosphatase activity was seen to be located in contact with all of the cell membranes facing the intercellular spaces. In preneoplastic alterations, the enzyme activity was found along the cell membranes of the basal and suprabasal cells of the epithelial pegs and numerous dense deposits of lead phosphate could be seen on the surfaces of the cytoplasmic processes and in the enlarged intercellular spaces. The intensity of the reaction in preneoplastic conditions was greater than in the normal epidermis. No adenosine triphosphatase activity was observed in the cell membranes facing the basement membrane or in the desmosomes. In carcinoma a less intensive adenosine triphosphatase reaction was present and could be recognized on the surface of only few tumor cells.

scholarly journals THE LOCALIZATION OF ENZYME ACTIVITIES IN THE RAT BRAIN

1960 ◽  
Vol 8 (3) ◽  
pp. 649-663 ◽  
Author(s):  
Norwin H. Becker ◽  
Sidney Goldfischer ◽  
Woo-Yung Shin ◽  
Alex B. Novikoff
Keyword(s):  
Rat Brain ◽  
Cell Membranes ◽  
Reductase Activity ◽  
Frozen Sections ◽  
Fixed Tissue ◽  
Quantitative Histochemistry ◽  
Capillary Endothelial Cells ◽  
Intracellular Organelles ◽  
The Brain ◽  
Nissl Substance

Studies with rat brain illustrate the usefulness of formol-calcium-fixed tissue for studying both enzymatic "chemoarchitectonics" and intracellular organelles. Unembedded frozen sections and polyvinyl alcohol-embedded sections may be used to demonstrate the activities of DPNH-tetrazolium reductase localized in mitochondria and ergastoplasm, TPNH-tetrazolium reductase localized in mitochondria, ATPase (and/or apyrase or ADPase) in cell membranes, and acid phosphatase in lysosomes.1 Among the observations recorded are: (1) the presence of lysosomes in all cells of the brain; (2) the presence of numerous large lysosomes near the nuclei of capillary endothelial cells; (3) a polarized arrangement of large lysosomes in epithelial cells of the ependyma and choroid plexus; (4) the presence of ATPase activity in the cell membranes of some neurons; (5) the presence of either an apyrase or combination of ATPase and ADPase in the cell membranes of neuroglia and capillaries; (6) the presence of both DPNH- and TPNH-tetrazolium reductase activities in neuroglia; (7) the presence of DPNH- and TPNH-tetrazolium reductase activities in mitochondria and of DPNH-tetrazolium reductase activity in Nissl substance. The possible functional significance of these localizations is briefly discussed, as is their relation to "quantitative histochemistry" data available in the literature.

A developmental and ultrastructural study of the optic chiasma in Xenopus

Development ◽  
1988 ◽  
Vol 102 (3) ◽  
pp. 537-553
Author(s):  
M.A. Wilson ◽  
J.S. Taylor ◽  
R.M. Gaze
Keyword(s):  
Optic Nerve ◽  
Cell Mass ◽  
Light And Electron Microscopy ◽  
Optic Tract ◽  
Retinal Ganglion ◽  
Intercellular Spaces ◽  
Optic Chiasma ◽  
Cell Processes ◽  
Optic Axons ◽  
The Brain

The structure of the optic chiasma in Xenopus tadpoles has been investigated by light and electron microscopy. Where the optic nerve approaches the chiasma, a tongue of cells protrudes from the periventricular cell mass into the dorsal part of the nerve. Glial processes from this tongue of cells ensheath fascicles of optic axons as they enter the brain. Coincident with this partitioning, the annular arrangement of axons in the optic nerve changes to the laminar organization of the optic tract. Beyond the site of this rearrangement, all newly growing axons accumulate in the ventral-most part of the nerve and pass into the region between the periventricular cells and pia which we have called the ‘bridge’. This region is characterized by a loose meshwork of glial cell processes, intercellular spaces and the presence of both optic and nonoptic axons. In the bridge, putative growth cones of retinal ganglion cell axons are found in the intercellular spaces in contact with both the glia and with other axons. The newly growing axons from each eye cross in the bridge at the midline and pass into the superficial layers of the contralateral optic tracts. As the system continues to grow, previous generations of axon, which initially crossed in the existing bridge, are displaced dorsally and caudally, forming the deeper layers of the chiasma. At their point of crossing in the deeper layers, these fascicles of axons from each eye interweave in an intimate fashion. There is no glial segregation of the older axons as they interweave within the chiasma.

scholarly journals Defective Associations between Blood Vessels and Brain Parenchyma Lead to Cerebral Hemorrhage in Mice Lacking αv Integrins

2002 ◽  
Vol 22 (21) ◽  
pp. 7667-7677 ◽  
Author(s):  
Joseph H. McCarty ◽  
Rita A. Monahan-Earley ◽  
Lawrence F. Brown ◽  
Markus Keller ◽  
Holger Gerhardt ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Vascular Endothelial Cells ◽  
Light And Electron Microscopy ◽  
Brain Parenchyma ◽  
Cell Junctions ◽  
Integrin Subunit ◽  
Cerebral Microvessels ◽  
Neuronal Precursors ◽  
Intracerebral Hemorrhages ◽  
Parenchymal Cells

ABSTRACT Mouse embryos genetically null for the αv integrin subunit develop intracerebral hemorrhages at midgestation and die shortly after birth. A key question is whether the hemorrhage arises from primary defects in vascular endothelial cells or pericytes or from other causes. We have previously reported normal initiation of cerebral vessels comprising branched tubes of endothelial cells. Here we show that the onset of hemorrhage is not due to defects in pericyte recruitment. Additionally, most αv-null vessels display ultrastructurally normal endothelium-pericyte associations and normal interendothelial cell junctions. Thus, endothelial cells and pericytes appear to establish their normal relationships in cerebral microvessels. However, by both light and electron microscopy, we detected defective associations between cerebral microvessels and the surrounding brain parenchyma, composed of neuroepithelial cells, glia, and neuronal precursors. These data suggest a novel role for αv integrins in the association between cerebral microvessels and central nervous system parenchymal cells.

Horseradish Peroxidase Permeation from the Capillaries of the Stria Vascularis after Inoculation of Endotoxin into the Middle Ear

1997 ◽  
Vol 106 (5) ◽  
pp. 394-398 ◽  
Author(s):  
Kensuke Watanabe ◽  
Yasuo Tanaka
Keyword(s):  
Horseradish Peroxidase ◽  
Middle Ear ◽  
Stria Vascularis ◽  
Femoral Vein ◽  
Cell Junctions ◽  
Intercellular Spaces ◽  
Basal Turn ◽  
Pinocytotic Vesicles ◽  
Marginal Cells ◽  
Intermediate Cells

Escherichia coli-derived endotoxin was inoculated in the middle ear of guinea pigs 24 hours after being injected intraperitoneally. Twenty-four hours after the middle ear inoculation, horseradish peroxidase (HRP) was injected via the femoral vein and the permeability of HRP through the capillaries of the stria vascularis and the destination of the leaked HRP were examined. A large amount of HRP leaked out of the capillary through the opened endothelial cell junctions and penetrated the enlarged intercellular spaces. Leaked HRP entered the pinocytotic vesicles of the intermediate cells. Even slightly degenerated intermediate cells retained this function. The HRP penetrated the spongelike structure of the marginal cells leading to the intercellular space. This structure was not observed without endotoxin. The HRP could not pass to the cochlear duct through the tight junctions between marginal cells. Blood sludging was observed in the strial capillaries. It appeared more frequently in the upper three turns than in the basal turn. The HRP leakage out of the capillaries was observed not only in the upper three turns but also in the basal turn.

scholarly journals SILVER DEPOSITION IN THE CENTRAL NERVOUS SYSTEM AND THE HEMATOENCEPHALIC BARRIER STUDIED WITH THE ELECTRON MICROSCOPE

1955 ◽  
Vol 1 (2) ◽  
pp. 161-166 ◽  
Author(s):  
V. L. van Breemen ◽  
C. D. Clemente
Keyword(s):  
Choroid Plexus ◽  
Blood Brain Barrier ◽  
Cell Membranes ◽  
Area Postrema ◽  
Light And Electron Microscopy ◽  
Blood Stream ◽  
Brain Barrier ◽  
Perivascular Spaces ◽  
Silver Deposition ◽  
Blood Brain

For the purpose of studying the hematoencephalic barrier as it is concerned with silver circulating in the blood stream, silver nitrate was vitally administered to rats in their drinking water over periods of 6 to 8 months. The cerebrum, cerebellum, medulla, area postrema, and choroid plexus were prepared for light and electron microscopy. Silver deposition was found in the perivascular spaces in the choroid plexus, area postrema, in the medulla surrounding the area postrema, and in minute quantities in the cerebrum, cerebellum, and most of the medulla. Two levels of the hematoencephalic barrier were apparently demonstrated in our investigations. The endothelial linings of the vessels in the cerebrum, cerebellum, and medulla constitute the first threshold of the hematoencephalic barrier (specifically here, blood-brain barrier). The cell membranes adjacent to the perivascular spaces form the second threshold, as follows:—the neuroglial cell membranes in the cerebrum, cerebellum, and medulla (blood-brain barrier); the membranes of the neuroglial cells in the area postrema (blood-brain barrier); and the membranes of the epithelial cells of the choroid plexus (blood-cerebrospinal fluid barrier). This study deals with silver deposition and does not infer that the penetration of ionic silver, if present in the blood stream, would necessarily be limited to the regions described. Bleb-like structures were observed to cover the epithelial cell surfaces in the choroid plexus. They may be cellular projections increasing the cell surface area or they may be secretory droplets.

scholarly journals WOUND HEALING AND COLLAGEN FORMATION

1962 ◽  
Vol 12 (3) ◽  
pp. 533-551 ◽  
Author(s):  
Russell Ross ◽  
Earl P. Benditt
Keyword(s):  
Electron Microscopy ◽  
Wound Healing ◽  
Protein Synthesis ◽  
Small Groups ◽  
Guinea Pigs ◽  
Light And Electron Microscopy ◽  
Dense Matter ◽  
Skin Wounds ◽  
Intercellular Spaces ◽  
Collagen Formation

The sequence encountered in healing skin wounds in scorbutic guinea pigs has been examined by methods of light and electron microscopy. Linear incisions in the skin of female guinea pigs fed a scorbutigenic diet were allowed to heal. The wounds were removed for examination at 1, 3, 5, 9, and 14 days after wounding. The fibroblasts of the scorbutic wounds differ from those of the controls in three major aspects. First, little collagen is present within the intercellular spaces, although small groups of individual collagen fibrils can be found adjacent to some of the fibroblasts; in addition, large amounts of somewhat fibrillar, poorly structured, dense matter are present throughout the extracellular regions. The second alteration consists of large aggregates of intracytoplasmic lipid deposits present within the majority of the fibroblasts. Third, the endoplasmic reticulum of the fibroblasts is altered in form from that of the controls. The profiles of the cisternae are round, non-continuous within the plane of section, and are less extensively developed than in the controls. An increased macrophagic activity of the histiocytes is also described. These changes are discussed in light of the available biochemical data associated with this abnormality of protein synthesis.

Development of intercellular junctions in the pulmonary epithelium of the foetal lamb

1978 ◽  
Vol 32 (1) ◽  
pp. 307-324
Author(s):  
E.E. Schneeberger ◽  
D.V. Walters ◽  
R.E. Olver
Keyword(s):  
Electron Microscopy ◽  
Epithelial Cells ◽  
Tight Junctions ◽  
Lung Development ◽  
Light And Electron Microscopy ◽  
Intercellular Junctions ◽  
Intercellular Spaces ◽  
Thin Sections ◽  
Epithelial Tight Junctions ◽  
Foetal Lamb

The integrity of epithelial tight junctions in foetal mammalian lungs is essential to maintain the unique ionic composition of lung liquid, and to prevent leakage of serum proteins into peripheral air spaces. In the present study the development of intercellular junctions of the lining epithelium of foetal lamb lungs during gestation was examined by light and electron microscopy. Both thin sections and freeze-fracture replicas were examined by electron microscopy. By 39 days of gestation, epithelial tight junctions consist of a minimum of 3.1 +/− 1.6 (s.D.) and a maximum of 5.8 +/− 2.0 discontinuous rows of particles and short segments of strands on P face ridges and in complementary E face grooves, while from 58 to 76 days they are composed of a network of 4.3 +/− 1.6 to 7.7 +/− 1.9 focally interrupted P face strands. Complementary replicas show that many of the discontinuities on the P face are due to separation of junctional particles on to the E face during fracturing, and not to an absence of junctional particles. From 76 days to term, epithelial tight junctions (exclusive of upper airway epithelium which was not examined) resemble those of adult lungs, and consist of a continuous network of 4.5 +/− 2.0 to 7.5 +/− 2.5 P face strands and complementary particle-free grooves. Permeability measurements, published elsewhere, indicate that the epithelium is functionally ‘tight’ from 69 days onwards. Tight junctions in peripheral air-space epithelium, therefore, are structurally continuous and functionally ‘tight’ early in foetal lung development, and form seals at one end of long, narrow intercellular spaces; these features may be important for coupled ion and water transport. When the bounding epithelial cells become flattened, these narrow intercellular spaces remain intact as a result of complex interdigitations of adjacent cell membranes. Desmosomes were present throughout gestation near the abluminal side of the tight junctions and occasionally near the base of the intercellular space. These junctions may serve to connect cells to each other at a time when tight junctions may be mechanically weak. In addition, gap junctions are associated with tight junctions from the glandular through the canalicular stages of lung development. They disappear by 120 days when the epithelial cells are differentiated.

Stigma development and the stigmatic cuticle of Medicago scutellata

1985 ◽  
Vol 63 (4) ◽  
pp. 813-818 ◽  
Author(s):  
G. L. Kreitner ◽  
E. L. Sorensen
Keyword(s):  
Cell Walls ◽  
Light And Electron Microscopy ◽  
Single Layer ◽  
Intercellular Spaces ◽  
Self Pollination ◽  
Medicago Scutellata ◽  
Annual Medicago ◽  
Stigma Development ◽  
Medicago Species ◽  
Late Stages

The self-fertile annual Medicago species evolved from the cross-pollinated perennial species. We used light and electron microscopy to study the development and structure of the stigma in annual tetraploid Medicago scutellata (L.) Mill to help elucidate the mechanism of self-pollination. Immature stigmatic cells have extensive lipid deposits. During development, stigmatic cells become separated and cellular lipid is transferred to intercellular spaces as part of the copious stigmatic secretion. The cuticle of the stigma is lifted away from underlying cell walls and confines secretion around stigmatic cells. The cuticle is thin, about 75 nm, and is composed mainly of a single layer traversed by dense strands. The cuticle is virtually always disrupted during late stages of flower maturation, as evidenced by penetration of stain into the stigma. Self-pollination may occur without flower tripping.

scholarly journals Acrolein/glutaraldehyde as a fixative for combined light and electron microscopic immunocytochemical detection of pituitary hormones in immersion-fixed tissue.

1982 ◽  
Vol 30 (12) ◽  
pp. 1307-1310 ◽  
Author(s):  
P F Smith ◽  
D A Keefer
Keyword(s):  
Light And Electron Microscopy ◽  
Pituitary Hormones ◽  
Pituitary Hormone ◽  
Electron Microscopic ◽  
Electron Microscopic Immunocytochemistry ◽  
Fixed Tissue ◽  
Immunocytochemical Detection ◽  
Wide Range ◽  
Pituitary Glands ◽  
Immunocytochemical Studies

In an attempt to find a fixative that has a wide range of application in immunocytochemical studies of pituitary tissue, we have investigated the use of acrolein fixation followed by postfixation in osmium. Pituitary glands were excised and immersion-fixed in 2 or 5% acrolein/0.25% glutaraldehyde for 1, 2.5, 5, or 24 hr. Some tissues were subsequently postfixed in 1% OsO4 for 1.5 hr before embedding in Epon-Araldite. Sections were collected for both light and electron microscopic immunocytochemistry, employing several pituitary hormone antisera. Fixation for 2.5 hr with 2% acrolein/0.25% glutaraldehyde followed by osmication resulted in good staining for both light and electron microscopy with all antisera employed. Furthermore, the rapid penetration qualities of this fixative resulted in good ultrastructural preservation throughout the tissue.

Sign in / Sign up

Export Citation Format

Share Document