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 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.

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.

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 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.

scholarly journals Electron Microscopic Studies on Ovarian Oocytes and Unfertilized Tubal Ova in the Rat

1960 ◽  
Vol 7 (3) ◽  
pp. 567-574 ◽  
Author(s):  
D. Louise Odor
Keyword(s):  
Granulosa Cells ◽  
Plasma Membranes ◽  
Developmental Stages ◽  
Structural Characteristics ◽  
Polar Body ◽  
Electron Microscopic ◽  
Space Forms ◽  
First Polar Body ◽  
The Matrix ◽  
Microscopic Studies

Developing rat ova have been studied with the electron microscope. Special attention was paid to relations of ova to the granulosa cells, the developmental stages of ovarian follicles, and the cytology of the unfertilized tubal ova. The relationship of the oocyte to the surrounding granulosa cells was found to change from one of a simple apposition of the plasma membranes to a complex interdigitation of microvilli from the ovular surface and processes from the granulosa cells extending into the matrix of the zona pellucida. This complex interrelation is maintained until the formation of the first polar body is initiated. At this time no microvilli are found and the oolemma presents a gently undulating outline. Also at this time, a perivitelline space forms and the granulosa cell processes retract. In the unfertilized tubal ova no microvilli are present and the processes of the follicular cells are completely withdrawn. The cytoplasmic elements of the oocyte in various stages of development are described in some detail. Of particular interest is the change noted in position and degree of aggregation of the Golgi complex as maturation proceeds. The distribution and structural characteristics of the mitochondria, ergastoplasm, dense particles, and multivesicular bodies are described.

Electron microscopic studies on ultrathin frozen sections of lactating mouse mammary gland

1978 ◽  
Vol 36 (2) ◽  
pp. 46-47
Author(s):  
Jan Zarzycki ◽  
Joseph Szroeder
Keyword(s):  
Mammary Gland ◽  
Protein Denaturation ◽  
Chemical Constituents ◽  
Freeze Substitution ◽  
Electron Microscopic Examination ◽  
Mouse Mammary Gland ◽  
Electron Microscopic ◽  
Preparation Methods ◽  
Microscopic Studies ◽  
Ultrathin Frozen Sections

The mammary gland ultrastructure in various functional states is the object of our investigations. The material prepared for electron microscopic examination by the conventional chemical methods has several limitations, the most important are the protein denaturation processes and the loss of large amounts of chemical constituents from the cells. In relevance to this,one can't be sure about a degree the observed images are adequate to the realy ultrastructure of a living cell. To avoid the disadvantages of the chemical preparation methods,some autors worked out alternative physical methods based on tissue freezing / freeze-drying, freeze-substitution, freeze-eatching techniqs/; actually the technique of cryoultraraicrotomy,i,e.cutting ultrathin sections from deep frozen specimens is assented as a complete alternative method. According to the limitations of the routine plastic embbeding methods we were interested to analize the mammary gland ultrastructure during lactation by the cryoultramicrotomy method.

Early Development of Drug-Induced Hepatic Necrosis

1971 ◽  
Vol 29 ◽  
pp. 576-577
Author(s):  
F. G. Zaki ◽  
E. Detzi ◽  
C. H. Keysser
Keyword(s):  
Early Development ◽  
Hepatic Necrosis ◽  
Screening Tests ◽  
Dense Matrix ◽  
Sprague Dawley ◽  
Electron Microscopic ◽  
Drug Induced ◽  
Hepatocellular Damage ◽  
Sprague Dawley Rats ◽  
Microscopic Studies

This study represents the first in a series of investigations carried out to elucidate the mechanism(s) of early hepatocellular damage induced by drugs and other related compounds. During screening tests of CNS-active compounds in rats, it has been found that daily oral administration of one of these compounds at a dose level of 40 mg. per kg. of body weight induced diffuse massive hepatic necrosis within 7 weeks in Charles River Sprague Dawley rats of both sexes. Partial hepatectomy enhanced the development of this peculiar type of necrosis (3 weeks instead of 7) while treatment with phenobarbital prior to the administration of the drug delayed the appearance of necrosis but did not reduce its severity.Electron microscopic studies revealed that early development of this liver injury (2 days after the administration of the drug) appeared in the form of small dark osmiophilic vesicles located around the bile canaliculi of all hepatocytes (Fig. 1). These structures differed from the regular microbodies or the pericanalicular multivesicular bodies. They first appeared regularly rounded with electron dense matrix bound with a single membrane. After one week on the drug, these vesicles appeared vacuolated and resembled autophagosomes which soon developed whorls of concentric lamellae or cisterns characteristic of lysosomes (Fig. 2). These lysosomes were found, later on, scattered all over the hepatocytes.

Electron Microscopic identification of Pre-B Lymphocytes in the Bone Marrow of a Patient with Chronic Myelocytic Leukemic in Blast Crisis

1982 ◽  
Vol 40 ◽  
pp. 346-347
Author(s):  
T. Mullin ◽  
G. Yee ◽  
M. Aheam ◽  
J. Trujillo
Keyword(s):  
Blast Crisis ◽  
Immunoglobulin M ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Transformation Theory ◽  
Electron Microscopic ◽  
Chemotherapeutic Sensitivity ◽  
Microscopic Studies ◽  
Hematopoietic Precursor ◽  
Lymphoblastic Transformation ◽  
B Lineage

There have been numerous reports in the current literature suggesting that hematopoietic precursor cells in some human chronic myelocytic leukemias (CML) undergo lymphoblastic transformation at the time of the acute blast crisis (BC) stage. The primary evidence offered in support of this transformation theory--lymphoblastic appearing morphology, increased terminal deoxynucleotidyl transferase (TdT) activity, and chemotherapeutic sensitivity to vincristine and prednisone--has been indirect, however, since these features may occur in nonlymphoid cells. More direct support for the Pre-B lineage of these cells has recently been provided by immunofluorescent light microscopic studies demonstrating the presence of intracytoplasmic immunoglobulin M (IgM) in these CML-BC cells.

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