scholarly journals Electron Microscopy of the Tapetum Lucidum of the Cat

1959 ◽  
Vol 5 (1) ◽  
pp. 35-39 ◽  
Author(s):  
Maurice H. Bernstein ◽  
Daniel C. Pease
Keyword(s):  
Electron Microscopy ◽  
Basement Membrane ◽  
Capillary Network ◽  
Structural Elements ◽  
Connective Tissue Layer ◽  
Retinal Surface ◽  
Cell Layers ◽  
Retinal Epithelium ◽  
The Individual ◽  
Similar Density

The fine structure of the tapetum of the cat eye has been investigated by electron microscopy. The tapetum is made up of modified choroidal cells, seen as polygonal plates grouped around penetrating blood vessels which terminate in the anastomosing capillary network of the choriocapillaris. The tapetal cells are rectangular in cross-section, set in regular brick-like rows, and attain a depth of some thirty-five cell layers in the central region. This number is gradually reduced peripherally, and is replaced at the margin of the tapetum by normal choroidal tissue. The individual cells are packed with long slender rods 0.1 µ by 4 to 5 µ. The rods are packed in groups and with their long axes oriented roughly parallel to the plane of the retinal surface. Each cell contains several such groups. Cells at the periphery or in the outer layers of the tapetum are frequently seen to contain both tapetal rods and melanin granules, the latter typical of the choroidal melanocytes. Also melanocyte granules may have intermediate shapes. These observations plus the similar density of the two inclusions lead to the belief that the tapetal rods may be melanin derivatives. A fibrous connective tissue layer lies between the tapetum and the retina. The subretinal capillary network, the choriocapillaris, rests on this layer and is covered by the basement membrane of the retinal epithelium. The cytoplasm of the retinal epithelium exhibits marked absorptive modifications where it comes in contact with the vessels of the choriocapillaris. This fibrous layer and the basement membrane of the retinal epithelium apparently comprise the structural elements of Bruch's membrane.

The Ultrastructure of Monkey Gingival Epithelium

1967 ◽  
Vol 25 ◽  
pp. 16-17
Author(s):  
C.N. Sun
Keyword(s):  
Epithelial Cells ◽  
Macaca Nemestrina ◽  
Stratum Granulosum ◽  
Solution Ph ◽  
Gingival Epithelial Cells ◽  
Stratum Spinosum ◽  
Cell Layers ◽  
Gingival Epithelium ◽  
The Individual ◽  
Different Thickness

The present study demonstrates the ultrastructure of the gingival epithelium of the pig tail monkey (Macaca nemestrina). Specimens were taken from lingual and facial gingival surfaces and fixed in Dalton's chrome osmium solution (pH 7.6) for 1 hr, dehydrated, and then embedded in Epon 812.Tonofibrils are variable in number and structure according to the different region or location of the gingival epithelial cells, the main orientation of which is parallel to the long axis of the cells. The cytoplasm of the basal epithelial cells contains a great number of tonofilaments and numerous mitochondria. The basement membrane is 300 to 400 A thick. In the cells of stratum spinosum, the tonofibrils are densely packed and increased in number (fig. 1 and 3). They seem to take on a somewhat concentric arrangement around the nucleus. The filaments may occur scattered as thin fibrils in the cytoplasm or they may be arranged in bundles of different thickness. The filaments have a diameter about 50 A. In the stratum granulosum, the cells gradually become flatted, the tonofibrils are usually thin, and the individual tonofilaments are clearly distinguishable (fig. 2). The mitochondria and endoplasmic reticulum are seldom seen in these superficial cell layers.

Scanning Electron Microscopy of Human Jejunum in Whipple's Disease

1977 ◽  
Vol 35 ◽  
pp. 354-355
Author(s):  
John H. L. Watson ◽  
C. N. Sun
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Basement Membrane ◽  
Lamina Propria ◽  
Brush Border ◽  
Whipple’S Disease ◽  
Whipple's Disease ◽  
Biopsy Specimens ◽  
Brush Borders ◽  
Scanning Electron

That the etiology of Whipple's disease could be bacterial was first suggested from electron micrographs in 1960. Evidence for binary fission of the bacteria, their phagocytosis by histiocytes in the lamina propria, their occurrence between and within the cells of the epithelium and on the brush border of the lumen were reported later. Scanning electron microscopy has been applied by us in an attempt to confirm the earlier observations by the new technique and to describe the bacterium further. Both transmission and scanning electron microscopy have been used concurrently to study the same biopsy specimens, and transmission observations have been used to confirm those made by scanning.The locations of the brush borders, the columnar epithelial cells, the basement membrane and the lamina propria beneath it were each easily identified by scanning electron microscopy. The lamina propria was completely filled with the wiener-shaped bacteria, Fig. 1.

Ultrastructural Study of Human Testicular Biopsies in Infertility

1976 ◽  
Vol 34 ◽  
pp. 156-157
Author(s):  
Shirley Siew ◽  
Philip Troen ◽  
Howard R. Nankin
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Basement Membrane ◽  
Leydig Cells ◽  
Clinical Evidence ◽  
Young Male ◽  
Germinal Epithelium ◽  
Transmission Electron ◽  
Age Range ◽  
Male Subjects

Testicular biopsies were obtained from six young male subjects (age range 24-33) who complained of infertility and who had clinical evidence of oligospermia. This was confirmed on histological examination which showed a broad spectrum from profound hypospermatogenesis to relatively normal appearing germinal epithelium. Thickening of the tubular walls was noted in half of the cases and slight peritubular fibrosis in one. The Leydig cells were reported as normal or unremarkable.Transmission electron microscopy showed that the thickening of the supporting tissue of the germinal epithelium was caused more by an increase in the thickness of the layers of the lamina propria than of the tubular wall itself. The changes in the basement membrane of the tubular wall consisted mostly of a greater degree of infolding into the tubule and some reduplication which gave rise to a multilayered appearance.

The blister of porphyria cutanea tarda: A Scanning and Transmission Electron Microscopic study

1986 ◽  
Vol 44 ◽  
pp. 334-335
Author(s):  
Veronika Burmeister ◽  
R. Swaminathan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Basement Membrane ◽  
Middle Age ◽  
Porphyria Cutanea Tarda ◽  
Minor Trauma ◽  
Electron Microscopic ◽  
Transmission Electron Microscopic Study ◽  
Transmission Electron ◽  
Transmission Electron Microscopic

Porphyria cutanea tarda (PCT) is a disorder of porphyrin metabolism which occurs most often during middle age. The disease is characterized by excessive production of uroporphyrin which causes photosensitivity and skin eruptions on hands and arms, due to minor trauma and exposure to sunlight. The pathology of the blister is well known, being subepidermal with epidermodermal separation, it is not always absolutely clear, whether the basal lamina is attached to the epidermis or the dermis. The purpose of our investigation was to study the attachment of the basement membrane in the blister by comparing scanning with transmission electron microscopy.

scholarly journals Cross-Linking Effects Dictate the Preference of Galectins to Bind LacNAc-Decorated HPMA Copolymers

2021 ◽  
Vol 22 (11) ◽  
pp. 6000
Author(s):  
Sara Bertuzzi ◽  
Ana Gimeno ◽  
Ane Martinez-Castillo ◽  
Marta G. Lete ◽  
Sandra Delgado ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Lectin Binding ◽  
Building Blocks ◽  
Cryo Electron Microscopy ◽  
Hpma Copolymers ◽  
Hydroxypropyl Methacrylamide ◽  
Galectin 3 ◽  
Nmr Methods ◽  
The Individual ◽  
Statistical Effects

The interaction of multi-LacNAc (Galβ1-4GlcNAc)-containing N-(2-hydroxypropyl) methacrylamide (HPMA) copolymers with human galectin-1 (Gal-1) and the carbohydrate recognition domain (CRD) of human galectin-3 (Gal-3) was analyzed using NMR methods in addition to cryo-electron-microscopy and dynamic light scattering (DLS) experiments. The interaction with individual LacNAc-containing components of the polymer was studied for comparison purposes. For Gal-3 CRD, the NMR data suggest a canonical interaction of the individual small-molecule bi- and trivalent ligands with the lectin binding site and better affinity for the trivalent arrangement due to statistical effects. For the glycopolymers, the interaction was stronger, although no evidence for forming a large supramolecule was obtained. In contrast, for Gal-1, the results indicate the formation of large cross-linked supramolecules in the presence of multivalent LacNAc entities for both the individual building blocks and the polymers. Interestingly, the bivalent and trivalent presentation of LacNAc in the polymer did not produce such an increase, indicating that the multivalency provided by the polymer is sufficient for triggering an efficient binding between the glycopolymer and Gal-1. This hypothesis was further demonstrated by electron microscopy and DLS methods.

On the Utility of Crystal Plasticity Modeling to Uncover the Individual Roles of Microdeformation Mechanisms on the Work Hardening Response of Fe-23Mn-0.5C TWIP Steel in the Presence of Hydrogen

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
B. Bal ◽  
M. Koyama ◽  
D. Canadinc ◽  
G. Gerstein ◽  
H. J. Maier ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Embrittlement ◽  
Twip Steel ◽  
Strain Response ◽  
Deformation Response ◽  
Self Consistent ◽  
Twip Steels ◽  
Simulation Results ◽  
The Individual ◽  
Experimental Findings

This paper presents a combined experimental and theoretical analysis focusing on the individual roles of microdeformation mechanisms that are simultaneously active during the deformation of twinning-induced plasticity (TWIP) steels in the presence of hydrogen. Deformation responses of hydrogen-free and hydrogen-charged TWIP steels were examined with the aid of thorough electron microscopy. Specifically, hydrogen charging promoted twinning over slip–twin interactions and reduced ductility. Based on the experimental findings, a mechanism-based microscale fracture model was proposed, and incorporated into a visco-plastic self-consistent (VPSC) model to account for the stress–strain response in the presence of hydrogen. In addition, slip-twin and slip–grain boundary interactions in TWIP steels were also incorporated into VPSC, in order to capture the deformation response of the material in the presence of hydrogen. The simulation results not only verify the success of the proposed hydrogen embrittlement (HE) mechanism for TWIP steels, but also open a venue for the utility of these superior materials in the presence of hydrogen.

The Tegument and Associated Structures of Fasciola Hepatica

1963 ◽  
Vol s3-104 (68) ◽  
pp. 505-512
Author(s):  
L. T. THREADGOLD
Keyword(s):  
Electron Microscopy ◽  
Surface Layer ◽  
Light Microscopy ◽  
Fasciola Hepatica ◽  
Golgi Bodies ◽  
New Knowledge ◽  
Pinocytotic Vesicles ◽  
The Individual ◽  
And Function ◽  
Internal Level

The cuticle of light microscopy is shown by electron microscopy to be a surface layer of protoplasm which is an extension of areas of nucleated protoplasm lying deep in the parenchyma. The cuticle therefore exists at two levels. The external level is syncytial, consisting of plateaux separated by branching valleys. This level contains apical pinocytotic vesicles, numerous mitochondria, endoplasmic membranes, large basal and other vacuoles, and dense spines. Tube-like evaginations from the base of the external level connect it to the individual areas of flask-shaped protoplasm which compose the internal level. Each of these areas of protoplasm contains a nucleus, great numbers of mitochondria, some vacuoles and diffuse inclusions, and the Golgi bodies. The histochemistry and function of the cuticle is discussed in the light of this new knowledge of cuticular ultrastructure, and a comparison is made between the cuticle of Cestoda and Trematoda.

Taxonomic application of macro and micro morphological characters of seeds in Astragalus L. (Galegeae, Fabaceae) in India

Phytotaxa ◽  
2021 ◽  
Vol 502 (2) ◽  
pp. 191-207
Author(s):  
SHIVANI KASHYAP ◽  
CHANDAN KUMAR SAHU ◽  
ROHIT KUMAR VERMA ◽  
LAL BABU CHAUDHARY
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Light Microscopy ◽  
Seed Coat ◽  
Morphological Plasticity ◽  
Morphological Characters ◽  
Individual Species ◽  
Large Size ◽  
The Individual ◽  
Scanning Electron

Due to large size and enormous morphological plasticity, the taxonomy of the genus Astragalus is very complex and challenging. The identification and grouping of species chiefly based on macromorphological characters become sometimes difficult in the genus. In the present study, the micromorphology of the seeds of 30 species belonging to 14 sections of Astragalus from India has been examined applying scanning electron microscopy (SEM) along with light microscopy (LM) to evaluate their role in identification and classification. Attention was paid to colour, shape, size and surface of seeds. The overall size of the seeds ranges from 1.5–3.2 × 0.8–2.2 mm. The shape of the seeds is cordiform, deltoid, mitiform, orbicular, ovoid and reniform. The colour of seeds varies from brown to blackish-brown to black. Papillose, reticulate, ribbed, rugulate and stellate patterns were observed on the seed coat surface (spermoderm) among different species. The study reveals that the seed coat ornamentations have evolved differently among species and do not support the subgeneric and sectional divisions of the genus. However, they add an additional feature to the individual species, which may help in identification in combination with other macro-morphological features.

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