scholarly journals FURTHER OBSERVATIONS ON THE FINE STRUCTURE OF THE PARIETAL EYE OF LIZARDS

1960 ◽  
Vol 8 (2) ◽  
pp. 483-499 ◽  
Author(s):  
Richard M. Eakin ◽  
Jane A. Westfall
Keyword(s):  
Lipid Droplets ◽  
Ganglion Cells ◽  
Nerve Fibers ◽  
Microscopical Study ◽  
Pigment Cells ◽  
Sceloporus Occidentalis ◽  
Neural Connections ◽  
System A ◽  
Electron Microscopical ◽  
Parietal Eye

An electron microscopical study of the third eye of the Western Fence Lizard, Sceloporus occidentalis, fixed with 1 per cent osmium tetroxide, pH 7.4–7.6, for 16 to 20 hours at 0°C., revealed the following new facts. The fibrillar system of the retinal photoreceptor consists of nine double fibrils enclosed in a sheath. Pigment cells and lens cells possess similar systems. Two short cylindrical centrioles are associated with the fibrillar apparatus: one, from which striated rootlets extend inward, lies at the base of the fibrils, with the other at an oblique angle to the axis of the system. A Golgi complex, whorls of endoplasmic reticulum, lipid (?) droplets, and other organelles and inclusions in the photoreceptors are described. An axon leads from the base of the photoreceptor into the nervous layer of the retina which consists of many nerve fibers and large ganglion cells. Although the pattern of neural connections has not yet been determined, some synapses were found. The parietal nerve consists of about 250 non-medullated fibers. The capsule of the eye usually has a layer of iridocytes, which contain rows of guanine (?) rods. A few parietal eyes of the Granite Night Lizard, Xantusia henshawi, were also examined. Large lipid (?) droplets occur in the bases of their receptoral processes.

Electron microscopical study to assess thein vitroeffects of the synthetic trioxolane OZ78 against the liver fluke,Fasciola hepatica

Parasitology ◽  
2009 ◽  
Vol 136 (11) ◽  
pp. 1325-1337 ◽  
Author(s):  
L. HALFERTY ◽  
J. F. O'NEILL ◽  
G. P. BRENNAN ◽  
J. KEISER ◽  
I. FAIRWEATHER
Keyword(s):  
Endoplasmic Reticulum ◽  
Lipid Droplets ◽  
Fasciola Hepatica ◽  
Microscopical Study ◽  
Granular Endoplasmic Reticulum ◽  
Autophagic Vacuoles ◽  
Transmission Electron ◽  
Electron Microscopical ◽  
Tegumental Syncytium

SUMMARYAdultFasciola hepaticawere incubated for 48 hin vitroin the synthetic peroxide, OZ78 at a concentration of 100 μg/ml and then prepared for scanning and transmission electron microscopy. There was limited disruption to the external fluke surface, with only slight swelling and blebbing of the interspinal tegument in the midbody and ventral tail regions. By contrast, significant disruption was observed to the ultrastructure of the tegument and subtegumental tissues. There was severe swelling of the basal infolds in the tegumental syncytium and the flooding spread internally to affect the subtegumental tissues. In the tegumental system, there was swelling of the cisternae of granular endoplasmic reticulum and of the mitochondria, with the latter showing signs of breaking down. Autophagic vacuoles and lipid droplets were present and the synthesis of tegumental secretory bodies was much reduced. The gastrodermal cells were severely affected, with swelling and degeneration of the mitochondria and the presence of autophagic vacuoles and lipid droplets. The granular endoplasmic reticulum was swollen and vesiculated and the cells contained few secretory bodies. Both the vitelline and testis follicles showed evidence of extensive cellular disruption and degeneration. This study confirms previous data indicating the potential flukicidal activity of OZ78.

Etching of Polymers by Oxygen Plasma

1968 ◽  
Vol 26 ◽  
pp. 408-409
Author(s):  
Virgil Peck ◽  
W. L. Carter
Keyword(s):  
Molecular Weight ◽  
Oxygen Plasma ◽  
Flow Time ◽  
Microscopical Study ◽  
Surface Layers ◽  
Organic Vapors ◽  
Sample Position ◽  
Accuracy Of Measurement ◽  
Bulk Polymers ◽  
Electron Microscopical

Any electron microscopical study of the morphology of bulk polymers has throughout the years been hampered by the lack of any real ability to produce meaningful surface variations for replication. True etching of polymers should show crystalline and amorphous regions in some form of relief. The use of solvents, acids, organic vapors, and inert ion bombardment to etch samples has proved to be useful only in limited applications. Certainly many interpretations of these results are subject to question.The recent use of a radiofrequency (R. F.) plasma of oxygen to degrade and remove organic material with only minor heating has opened a new possibility for etching polymers. However, rigid control of oxygen flow, time, current, and sample position are necessary in order to obtain reproducible results. The action is confined to surface layers; the molecular weight of the polymer residue after heavy etching is the same as the molecular weight of the polymer before attack, within the accuracy of measurement.

LIGHT AND ELECTRON MICROSCOPICAL STUDY OF THE EFFECT OF OESTROGEN ON THE CHICKEN OVIDUCT

1967 ◽  
Vol 56 (3) ◽  
pp. 391-402 ◽  
Author(s):  
H. I. Ljungkvist
Keyword(s):  
Secretory Granules ◽  
Apical Cell ◽  
Cell Types ◽  
Microscopical Study ◽  
List Type ◽  
New Production ◽  
General Increase ◽  
Chicken Oviduct ◽  
Electron Microscopical ◽  
Aortic Perfusion

ABSTRACT Oviducts from 20 one-day old chickens were used. Ten chickens were injected subcutaneously with 0.2 mg oestradiol for 5 days, the remaining ones serving as controls. The chickens were fixed by an aortic perfusion with 2.5% glutaraldehyde in phosphate buffer, pH 7.2. The treatment with oestrogen resulted in the following changes: general increase in oviduct length and thickness, differentiation of the epithelial membrane into three cell types: basal, apical and gland cells, increase in the number of cilia in the apical cell, probably due to a new production of cilia, formation of secretory granules in the vaginal epithelium as seen by light microscopy, formation of proteinlike secretory granules in the apical cell as seen by electron microscopy, increase in protein synthesis, observed as an augmentation of the endoplasmic reticulum.

Melatonin As a Modulator of Degenerative and Regenerative Signaling Pathways in Injured Retinal Ganglion Cells

2019 ◽  
Vol 25 (28) ◽  
pp. 3057-3073 ◽  
Author(s):  
Kobra B. Juybari ◽  
Azam Hosseinzadeh ◽  
Habib Ghaznavi ◽  
Mahboobeh Kamali ◽  
Ahad Sedaghat ◽  
...  
Keyword(s):  
Optic Nerve ◽  
Mitochondrial Dysfunction ◽  
Signaling Pathways ◽  
Retinal Ganglion Cells ◽  
Molecular Mechanisms ◽  
Nitrosative Stress ◽  
Ganglion Cells ◽  
Axon Growth ◽  
Nerve Fibers ◽  
Retinal Ganglion

Optic neuropathies refer to the dysfunction or degeneration of optic nerve fibers caused by any reasons including ischemia, inflammation, trauma, tumor, mitochondrial dysfunction, toxins, nutritional deficiency, inheritance, etc. Post-mitotic CNS neurons, including retinal ganglion cells (RGCs) intrinsically have a limited capacity for axon growth after either trauma or disease, leading to irreversible vision loss. In recent years, an increasing number of laboratory evidence has evaluated optic nerve injuries, focusing on molecular signaling pathways involved in RGC death. Trophic factor deprivation (TFD), inflammation, oxidative stress, mitochondrial dysfunction, glutamate-induced excitotoxicity, ischemia, hypoxia, etc. have been recognized as important molecular mechanisms leading to RGC apoptosis. Understanding these obstacles provides a better view to find out new strategies against retinal cell damage. Melatonin, as a wide-spectrum antioxidant and powerful freeradical scavenger, has the ability to protect RGCs or other cells against a variety of deleterious conditions such as oxidative/nitrosative stress, hypoxia/ischemia, inflammatory processes, and apoptosis. In this review, we primarily highlight the molecular regenerative and degenerative mechanisms involved in RGC survival/death and then summarize the possible protective effects of melatonin in the process of RGC death in some ocular diseases including optic neuropathies. Based on the information provided in this review, melatonin may act as a promising agent to reduce RGC death in various retinal pathologic conditions.

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