scholarly journals ELECTRON MICROSCOPIC STUDIES ON THE INDIRECT FLIGHT MUSCLES OFDROSOPHILAMELANOGASTER

1963 ◽  
Vol 17 (2) ◽  
pp. 363-0373 ◽  
Author(s):  
S. Ahmad Shafiq
Keyword(s):  
Cell Membranes ◽  
Plasma Membranes ◽  
Electron Microscopic ◽  
Cytoplasmic Inclusions ◽  
Fibrillar Material ◽  
Microscopic Studies ◽  
Flight Muscles ◽  
The Individual

The differentiation of the indirect flight muscles was studied in the various pupal stages of Drosophila. Fibrillar material originates in the young basophilic myoblasts in the form of short myofilamants distributed irregularly near the cell membranes. The filaments later become grouped into bundles (fibrils). Certain "Z bodies" appear to be important during this process. The "Z bodies" may possibly be centriolar derivatives and are the precursors of the Z bands. The first formed fibrils (having about 30 thick myofilaments) are already divided into sarcomeres by Z bands. These sarcomeres, however, seem to be shorter than those of the adult fibrils.The H band differentiates in fibrils having about 40 thick myofilaments; the fibrils constrict in the middle of each sarcomere during this process. The individual myofibrils increase from about 0.3 µ to 1.5 µ in diameter during development, apparently by addition of new filaments on the periphery of the fibrils. The ribosomes seem to be the only cytoplasmic inclusions which are closely associated with these growing myofibrils. Disintegration of the plasma membranes limiting individual myoblasts was commonly seen during development of flight muscles, supporting the view that the multinuclear condition of the fibers of these muscles is due to fusion of myoblasts.

BRIEF REPORT: Freeze-Cleaving of Red Cell Membranes in Paroxysmal Nocturnal Hemoglobinuria

Blood ◽  
1967 ◽  
Vol 30 (6) ◽  
pp. 785-791 ◽  
Author(s):  
RONALD S. WEINSTEIN ◽  
ROGER A. WILLIAMS
Keyword(s):  
Paroxysmal Nocturnal Hemoglobinuria ◽  
Cell Membranes ◽  
Red Cells ◽  
Red Cell ◽  
Electron Microscopic ◽  
Structural Differences ◽  
Microscopic Studies ◽  
Red Cell Membranes

Abstract Electron microscopic studies on dried isolated red cell ghosts have been reported to show lesions associated with cell membranes in paroxysmal nocturnal hemoglobinuria (PNH). In this study, carbon-platinum replicas of membranes of freeze-cleaved, partially hydrated PNH red cells and isolated PNH cell ghosts failed to confirm the existence of these abnormalities. This suggests that the previously described lesions are the products of drying artifacts, although they may reflect hidden structural differences between PNH and normal red cell membranes.

scholarly journals Platelet Satellitism

Blood ◽  
1974 ◽  
Vol 43 (6) ◽  
pp. 831-836 ◽  
Author(s):  
Carl R. Kjeldsberg ◽  
John Swanson
Keyword(s):  
Polymorphonuclear Leukocytes ◽  
Plasma Membranes ◽  
Clinical Importance ◽  
Electron Microscopic ◽  
Normal Platelet ◽  
Microscopic Studies ◽  
Platelet Satellitism ◽  
Platelet Functions

Abstract Platelet adherence to polymorphonuclear leukocytes, or so-called platelet satellitism, has, to our knowledge, been reported in only four patients. We had the opportunity to study this phenomenon in two patients. Platelet satellitism was only seen in EDTA anticoagulated blood, and the platelets were seen to surround polymorphonuclear leukocytes only. Electron microscopic studies demonstrated focally opposed regions of platelet and neutrophil plasma membranes. Phagocytosis of platelets was also observed. In vivo and in vitro platelet functions were normal. Platelet satellitism is an in vitro phenomenon, the cause of which is unknown. We are unable to relate it to functional abnormalitles of the blood, the clinical condition of the patient, or to drugs. This phenomenon has some clinical importance in that it causes spurious thrombocytopenia.

scholarly journals ELECTRON MICROSCOPIC STUDIES ON THE INDIRECT FLIGHT MUSCLES OF DROSOPHILA MELANOGASTER

1963 ◽  
Vol 17 (2) ◽  
pp. 351-362 ◽  
Author(s):  
S. Ahmad Shafiq
Keyword(s):  
Drosophila Melanogaster ◽  
Epidermal Cells ◽  
Uniform Density ◽  
Electron Microscopic ◽  
Thick Filaments ◽  
Irregular Pattern ◽  
Regular Arrangement ◽  
Microscopic Studies ◽  
Hexagonal Arrangement ◽  
Flight Muscles

The myofibrils in Drosophila have thick and thin types of myofilaments arranged in the hexagonal pattern described for Calliphora by Huxley and Hanson (15). The thick filaments, along most of their length in the A band, seem to be binary in structure, consisting of a dense cortex and a lighter medulla. In the H zone, however, they show more uniform density; lateral projections (bridges) also appear to be absent in this region. The M band has a varying number of granules (probably of glycogen) distributed between the myofilaments. The myofilaments on reaching the Z region appear to change their hexagonal arrangement and become connected to one another by Z filaments. The regular arrangement of the filaments found in most regions of the fibrils is not seen in the terminal sarcomeres of some flight muscles; the two types of filaments appear to be intermingled in an irregular pattern in these parts of the fibrils. The attachment of myofibrils to the cuticle through the epidermal cells is described.

The Ultrastructure of Crystalliferous Cells in Some Lecythidaceae With a Discussion of Their Terminology

IAWA Journal ◽  
1984 ◽  
Vol 5 (3) ◽  
pp. 229-236 ◽  
Author(s):  
N. Parameswaran ◽  
H.-G. Richter
Keyword(s):  
Electron Microscopic ◽  
Axial Parenchyma ◽  
Individual Crystal ◽  
Microscopic Studies ◽  
Per Se ◽  
The Individual

On the basis of a light microscopic c1assification of the genera of the Lecythidaceae according to the presence of crystalliferous cells in the axial wood parenchyma an attempt was made to characterise these cells at the fine structurallevel. Electron microscopic studies of the genera Allantoma, Grias and Gustavia revealed normal cross walls, as well as septumIike walls separating the individual crystal-containing units in the axial parenchyma strand. Based on these findings the terminology of the crystalliferous cells per se is discussed at some length.

scholarly journals SYNAPTIC STRUCTURES IN THE LATERAL LINE CANAL ORGAN OF THE TELEOST FISH LOTA VULGARIS

1962 ◽  
Vol 13 (2) ◽  
pp. 337-343 ◽  
Author(s):  
Åke Flock ◽  
Jan Wersäll
Keyword(s):  
Hair Cell ◽  
Lateral Line ◽  
Teleost Fish ◽  
Plasma Membranes ◽  
Sensory Epithelium ◽  
Electron Microscopic ◽  
Lateral Line Canal ◽  
Cell Plasma ◽  
Microscopic Studies ◽  
Synaptic Structures

This paper is a preliminary report on some of the results of electron microscopic studies on the lateral line canal organ of the teleost fish Lota vulgaris. It deals with the ultrastructure of the synaptic area on the hair cells of the sensory epithelium and describes the nerve endings as well as a complicated system of foldings of the hair cell plasma membranes enclosing portions of the hair cell cytoplasm in the synaptic area. These findings are discussed in the light of present knowledge of the ultrastructure of other receptoneuronal synapses.

scholarly journals Immuno-electron-microscopic studies on the subcellular distribution of rat liver epoxide hydrolase and the effect of phenobarbitone and 2-acetamidofluorene treatment

1982 ◽  
Vol 202 (3) ◽  
pp. 677-686 ◽  
Author(s):  
F Waechter ◽  
P Bentley ◽  
M Germann ◽  
F Oesch ◽  
W Stäubli
Keyword(s):  
Electron Microscopy ◽  
Rat Liver ◽  
Subcellular Distribution ◽  
Epoxide Hydrolase ◽  
Specific Binding ◽  
Subcellular Fractions ◽  
Electron Microscopic ◽  
Immuno Electron Microscopy ◽  
Microscopic Studies ◽  
The Individual

The distribution of rat liver epoxide hydrolase in various subcellular fractions was investigated by immuno-electron-microscopy. Ferritin-linked monospecific anti-(epoxide hydrolase) immunoglobulins bound specifically to the cytoplasmic surfaces of total microsomal preparations and smooth and rough microsomal fractions as well as the nuclear envelope. Specific binding was not observed when the ferritin conjugates were incubated with peroxisomes, lysosomes and mitochondria. The average specific ferritin load of the individual subcellular fractions correlated well with the measured epoxide hydrolase activities. This correlation was observed with fractions prepared from control, phenobarbitone-treated and 2-acetamidofluorene-treated rats.

Role of cell adhesion in contact-dependent transfer of a lysosomal enzyme from lymphocytes to fibroblasts

1986 ◽  
Vol 85 (1) ◽  
pp. 231-244
Author(s):  
I. Olsen ◽  
T. Oliver ◽  
H. Muir ◽  
R. Smith ◽  
T. Partridge
Keyword(s):  
Lysosomal Enzyme ◽  
Plasma Membranes ◽  
Fibroblast Cell ◽  
Active Role ◽  
Electron Microscopic ◽  
High Frequencies ◽  
Transmission Electron ◽  
Cell Enzyme ◽  
Microscopic Studies

Normal lymphocytes were found to adhere strongly to monolayer cultures of fibroblasts deficient in the lysosomal enzyme, beta-glucuronidase. During this co-culture, the fibroblasts acquired from the lymphocytes substantial amounts of this enzyme, which often accumulated at sites of contact between the two types of cell. Enzyme transfer was prevented by addition to the co-cultures either of purified lymphocyte plasma membranes or of antibody raised against such plasma membranes, but it was not inhibited by the addition of antibody raised against lymphocyte-derived beta-glucuronidase. An active role for the lymphocyte in this contact-dependent process was suggested by interference contrast, immunofluorescence and scanning electron-microscopic studies. These revealed extensive arrays of projections of the lymphocyte that ramified over the fibroblast cell surface. By transmission electron microscopy, conspicuous clusters of micropinocytotic vesicles were evident in the cytoplasm of the ‘recipient’ fibroblasts, subjacent to the surface in regions closely apposed to adherent lymphocytes. Such high frequencies of these vesicles were restricted to sites of lymphocyte-fibroblast contact, suggesting that they may play an important part in the transfer of enzyme between these two types of cell.

Effect of formaldehyde inhalation on rat livers: A light and electron microscopic study

2010 ◽  
Vol 26 (2) ◽  
pp. 113-119 ◽  
Author(s):  
Selman Cikmaz ◽  
Tunc Kutoglu ◽  
Mehmet Kanter ◽  
Recep Mesut
Keyword(s):  
Liver Tissue ◽  
Exposure Period ◽  
Electron Microscopic Level ◽  
Albino Rats ◽  
Electron Microscopic ◽  
Tissue Samples ◽  
Microscopic Evaluation ◽  
Microscopic Studies ◽  
Wistar Albino Rats ◽  
The Individual

It is well known that formaldehyde (FA) is cytotoxic and potentially carcinogenic. Although the individual effects of this reactant on cells has been investigated, the cytotoxicity exerted by the coexistence of FA is poorly understood. The aim of this study was to investigate the effects of FA on the liver in rats, by light and electron microscopic level. We used 18 Wistar albino rats divided into three groups, exposed to 0 (control), 19.7 ppm FA gas for a total of 4 weeks, 8 h/day, 5 days a week (subacute) and 20.3 parts per million (ppm) FA gas for a total of 13 weeks, 8 h/day, 5 days a week (subchronic). After the completion of the exposure period, they were sacrificed by decapitation and their liver tissue samples were taken in order to be processed for light and electron microscopic studies. Light microscopic evaluation of liver tissue samples of FA-exposed rats revealed enlarged sinusoids filled with blood and mononuclear cell infiltration in the portal areas and around the central veins. In addition, some of the hepatocytes showed loss of cytoplasm, and some had a hyperchromatic nucleus. The cells of FA-exposed livers, on the other hand, showed an electron-lucent ground-cytoplasm and a hypertrophy of the smooth-surfaced endoplasmic reticulum. In conclusion, we observed that exposure FA caused diverse histopathological changes indicating the destruction in the liver tissue and this destruction has direct relationship with the length of the exposure period.

scholarly journals Intercellular Bridges as Protoplasmic Anastomoses between Smooth Muscle Cells

1959 ◽  
Vol 6 (1) ◽  
pp. 67-70 ◽  
Author(s):  
J. C. Thaemert
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Smooth Muscle Cell ◽  
Action Potentials ◽  
Plasma Membranes ◽  
Muscular Activity ◽  
Muscle Cells ◽  
Electron Microscopic ◽  
Intercellular Bridges ◽  
Microscopic Studies

In electron microscopic studies, protoplasmic anastomoses were found to occur between smooth muscle cells in the gastrointestinal tracts of rats. The protoplasmic connections are apparently cylindrical in form and contain cytoplasm having a density similar to that of the cellular regions connected. The membranes enclosing the cytoplasmic connections are continuous with the membranes of the connected cells. These connecting structures have been called intercellular bridges, which is adequately descriptive if emphasis is placed on the interpretation that they represent protoplasmic anastomoses. To emphasize this, the term may be modified; i.e., anastomotic intercellular bridges. In some cellular connections, transverse diffuse lines are seen. These may be interpreted as either disintegrating or reforming plasma membranes which is consistent with the concept that protoplasmic continuity is transitory. Since the animals were dissected under hypothermia, reduction of muscular activity by the chilling may have helped to preserve the structure of existing anastomotic intercellular bridges. The intercellular protoplasmic anastomoses may play a role in the conduction of action potentials from one smooth muscle cell to another.

scholarly journals WOUND HEALING AND COLLAGEN FORMATION

1962 ◽  
Vol 15 (1) ◽  
pp. 99-108 ◽  
Author(s):  
Russell Ross ◽  
Earl P. Benditt
Keyword(s):  
Osmium Tetroxide ◽  
Unit Area ◽  
Modified Technique ◽  
Electron Microscopic ◽  
Collagen Formation ◽  
Fibrillar Material ◽  
Nuclear Track Emulsion ◽  
Microscopic Studies ◽  
Healing Wounds ◽  
Collagenous Material

The sequence of incorporation and utilization of tritium-labeled proline has been examined in healing wounds from normal and scorbutic guinea pigs. Linear incisions in the skin of the animals were allowed to heal for 7 days. Each animal was given proline-H3, and the wounds were excised 30 minutes, 1 and 4 hours, 1, 3 and 7 days after proline administration. The tissues were fixed in osmium tetroxide, fixed again in neutral buffered formalin, embedded in epoxy resin, and sectioned at 1 micron thickness. The sections were coated with nuclear track emulsion, exposed, developed, and stained. The results of grain counts were quantitated as the number of counts per unit area overlying cells, fibers, etc. In both groups the proline reaches a maximum over the fibroblasts within 4 hours and subsequently disappears from the cells. Concomitantly, the proline reaches a maximum over the collagen (in normal animals) and extracellular fibrillar material (in scorbutic animals) by 4 hours, where it remains. The modified technique of radioautography used in this study allows not only resolution of approximately 1 micron, but also minimal background, decreased artifact, and a clear separation of the randomly situated elements within the wounds so that grain counting is facilitated. The results correlated with previous electron microscopic studies are consistent with the utilization of proline by the fibroblasts and its incorporation into collagen (in normal animals) and into the extracellular, fibrillar, non-collagenous material seen in scorbutic animals.

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