Studies on the Receptors in the Cerebral Vesicle of the Ascidian Tadpole, I. The Otolith

1962 ◽  
Vol s3-103 (63) ◽  
pp. 393-398
Author(s):  
P. N. DILLY

Electron microscope observations of the gravity receptor of the tadpole larva of Ciona intestinalis show that the otolith is unicellular. The nucleus of the otolith persists for the entire life of the tadpole. The pigment mass of the otolith is intracellular, and it appears to be built up by fusion of granules. The otolith cell has a free part within the cavity of the cerebral vesicle, and a foot part which is contained within a mound of cells on the ventral wall of the cerebral vesicle. The junction between these two parts is probably the transducer region. The transducer region is a complex system of folded cell membrane. Distortion of this system during rotation of the tadpole while swimming probably evokes changes in the neurones which surround the foot process of the otolith cell. One of these neurones is connected to the cerebral ganglion by a process which may be an axon. Fibrils extend from the transducer region of the otolith cell to the basement membrane, and probably serve to resist distortion of the transducer region. The foot process of the otolith cell is connected to the surrounding cells by specializations of the cell membrane similar to attachment plaques. The observations suggest that the otolith has been evolved from a cilium.

1958 ◽  
Vol 4 (5) ◽  
pp. 529-538 ◽  
Author(s):  
George F. Obland

In the present investigation an analysis has been made of the fine structure of the interrelationships of cells in human forearm epidermis by means of the electron microscope. The "intercellular bridges," here called attachment zones, are more complex than has previously been recognized. It is shown that dense oval thickenings, called attachment plaques, appear in apposed areas of adjacent epidermal cell membranes. The tonofibrils terminate at the internal face of the attachment plaque and do not traverse the 300 A distance between apposed plaques. Seven intervening layers of unidentified substance occupy the space between attachment plaques. The attachment zones appear in all of the classical histological layers of the epidermis. The portions of epidermal cell membrane not involved in intercellular attachments have extensive surface area resulting from plication of the membrane, and its further modification to form microvilli. The possible functional significance of these observations is discussed. Prior observations concerning the basement membrane of epidermis are confirmed. Identification of epidermal melanocytes is achieved, the finer morphology of their dendritic processes is described, and their relationship to epidermal cells is discussed.


Author(s):  
R. A. Waugh ◽  
J. R. Sommer

Cardiac sarcoplasmic reticulum (SR) is a complex system of intracellular tubules that, due to their small size and juxtaposition to such electron-dense structures as mitochondria and myofibrils, are often inconspicuous in conventionally prepared electron microscopic material. This study reports a method with which the SR is selectively “stained” which facilitates visualizationwith the transmission electron microscope.


Author(s):  
R.P. Nayyar ◽  
C.F. Lange ◽  
J. L. Borke

Streptococcal cell membrane (SCM) antiserum injected mice show a significant thickening of glomerular basement membrane (GBM) and an increase in mesangial matrix within 4 to 24 hours of antiserum administration (1,2,3). This study was undertaken to evaluate the incorporation of 3H proline into glomerular cells and GBM under normal and anti-SCM induced conditions. Mice were administered, intraperitoneally, 0.1 ml of normal or anti-SCM serum followed by a 10 µC/g body weight injection of 3H proline. Details of the preparation of anti-SCM (Group A type 12 streptococcal pyogenes) and other sera and injection protocol have been described elsewhere (2). After 15 minutes of isotope injection a chase of cold proline was given and animal sacrificed at 20 minutes, 1,2,4,8,24 and 48 hours. One of the removed kidneys was processed for immunofluorescence, light and electron microscopic radioautographic studies; second kidney was used for GBM isolation and aminoacid analysis.


1959 ◽  
Vol s3-100 (49) ◽  
pp. 13-15
Author(s):  
K. DEUTSCH ◽  
M. M. SWANN

The fine structure of a species of small free-living amoeba, Hartmanella astronyxis, has been investigated. The mitochondria resemble those of other species of amoeba. Structureless bodies of about the same size as mitochondria are sometimes found in association with them. Double membranes are common in the cytoplasm, and may show granules along their outer borders. The nuclear membrane is a double-layered structure, with a honeycomb structure evident in tangential sections. The cell membrane is also double-layered, or occasionally multi-layered.


1978 ◽  
Vol 12 (4) ◽  
pp. 207-211 ◽  
Author(s):  
E. A. E. Van Marck ◽  
W. Jacob ◽  
A. M. Deelder ◽  
P. L. J. Gigase

Changes in apparently healthy hamsters, consistent with proteinuria, are reported, but no IgG deposits or amyloid in the glomeruli were detected. Further investigation is required into the significance and the aetiology of these, as yet, obscure alterations.


2015 ◽  
Vol 84 (3) ◽  
pp. 201-204
Author(s):  
Jakub Żurawski

Initially, the thin glomerular basement membrane disease was called “a gentle and curable hemorrhagic nephritis”. The thin basement membrane disease has been finally characterized at the beginning of 1970s. This is when the connection between previously clinically described gentle microhematuria and significant thinning of glomerular basement membrane discovered during examination under the electron-microscope has been established. Ultimately, the disease has been described as a condition characterized with a diverse clinical course, usually mild, but sometimes progressive. It is a family conditioned disease, but it also appears sporadically and concerns at least 1% of the population. It has also been stated that it is one of the most frequent renal diseases, enumerated directly after changes caused by infections, hypertension and renal lithiasis. This particular disease is diagnosed more often than IgA nephropathy and Alport syndrome, which are also associated with haematuria or microhematuria.


Development ◽  
1972 ◽  
Vol 27 (1) ◽  
pp. 1-13
Author(s):  
A. H. Sathananthan

The stratification of various cell organelles and of important chemical substances have been studied in the eggs of the slug, after moderate centrifugation. As in other molluscs the egg contents stratify typically into three well-defined zones - lipid, L hyaline and yolky zones - but a distinct equatorial band of inclusions consisting mainly of F phagosomes and associated lysosomes was detected in the most centrifugal region of the hyaline zone. The sub-stratification of various cell inclusions in their respective zones was determined in some detail. The role of the cell membrane and egg cortex in the redistribution of these inclusions and the nature of the ergastoplasm are discussed in the light of electron-microscope studies of eggs of this slug and of the sea urchin.


Physiology ◽  
2000 ◽  
Vol 15 (5) ◽  
pp. 255-259 ◽  
Author(s):  
Thomas Meier ◽  
Markus A. Ruegg

Dystroglycan contributes to the formation of basement membrane during embryonic development and enforces cell membrane integrity by bridging cytoskeleton and components of the extracellular matrix. In several forms of muscle disease, dystroglycan is reduced in abundance. Moreover, human viral and bacterial pathogens use dystroglycan as their cellular entry point.


1977 ◽  
Vol 47 (6) ◽  
pp. 955-960 ◽  
Author(s):  
Atsuo Koto ◽  
Dikran S. Horoupian ◽  
Kenneth Shulman

✓ A supratentorial cyst in the leptomeninges of an 8-month-old infant was studied with the electron microscope. The lining of the cyst consisted of a single layer of pegshaped epithelial cells rich in organelles and glycogen. Their free border had numerous microvilli but no cilia, and their basal portions rested on a basement membrane. Tight junctions and interdigitations were frequent between contiguous cells. The blood vessels were fenestrated. Since these features characterize developing choroidal epithelial cells, we felt the diagnosis of choroidal epithelial cyst was justified. Cysts lined by choroidal epithelium may continue to secrete cerebrospinal fluid after surgical extirpation when this is incomplete. Accumulation of the fluid in the partially excised cyst bed may therefore account for recurrence of symptoms.


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