scholarly journals MATURATION OF THE RAT FETAL THYROID

1961 ◽  
Vol 11 (2) ◽  
pp. 365-383 ◽  
Author(s):  
Joseph D. Feldman ◽  
Jacinto J. Vazquez ◽  
Stanley M. Kurtz
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Granular Endoplasmic Reticulum ◽  
Follicular Epithelium ◽  
Follicular Cells ◽  
Similar Material ◽  
Thyroid Cells ◽  
Fluorescence And Electron Microscopy ◽  
Fetal Thyroid ◽  
Cytoplasmic Structures

Maturation of the rat fetal thyroid was studied with the aid of I131 and of fluorescence and electron microscopy. The I131 concentration of the fetal gland increased exponentially from day 17 to day 20 of gestation and was related to the weight of the fetus (and presumably the weight of the thyroid) and also to the quantity of I131 accumulated by the fetus. In the 17-day gland, thyroglobulin or immunologically similar material was sparsely present in the incipient lumens of some cell clusters. With maturation, this material increased and was also observed within follicular cells on days 18 to 19 of gestation. On day 20, the specifically reacting material was present in the follicular lumens and was absent from the cytoplasm of follicular epithelium. Ultrastructurally, the earliest thyroid cells examined were replete with all the organelles found in the more mature epithelium. No direct correlation could be made between the cytoplasmic structures and the presence of thyroglobulin, although the granular endoplasmic reticulum was most likely the organelle responsible for synthesis of thyroglobulin. Thyroglobulin or a precursor was found in fetal thyroid cells before measurable quantities of I131 were concentrated and before cytoplasmic droplets appeared.

Fine structural observation on the oogenesis and vitellogenesis of the Chinese soft-shelled turtle (Pelodiseus sinensis)

Zygote ◽  
2009 ◽  
Vol 18 (2) ◽  
pp. 109-120 ◽  
Author(s):  
Hei Nainan ◽  
Yang Ping ◽  
Yang Yang ◽  
Liu Jinxiong ◽  
Bao Huijun ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Special Functions ◽  
Dorsal Surface ◽  
Sibling Relationship ◽  
Follicular Epithelium ◽  
Follicular Cells ◽  
Cell Organelles ◽  
Rough Endoplasmic Reticula ◽  
Relationship Of ◽  
Endoplasmic Reticula

SummaryFine structure observations were performed by means of electron microscopy on oogenesis and vitellogenesis and the special functions of follicular cells in the Chinese soft-shelled turtle (Pelodiseus sinensis). Histological examination of the ovary showed a well developed lacunae system containing fine granules, fibres or gelatiniform materials with one or two germinal beds dispersed on the dorsal surface of the ovarian cortex. The process of oogenesis comprised 10 consecutive phases according to the morphology of the yolk platelets, follicular cells and zona pellucida (ZP). Electron microscopy of vitellogenesis revealed some of the mitochondria gradually being transformed into yolk granules. In the advanced stage of vitellogenesis, large amounts of rough endoplasmic reticula, Golgiosomes and other cell organelles that are involved in synthesis and secretion were observed in follicular cells. The ZP was formed by microvilli, thus increasing the absorptive surface of the oocyte and facilitating transport of nutrients from the follicular epithelium to the ooplasm. This study demonstrated that the ovaries of members of the Testudinidae share more features with Archosaurs than with Squamates, indicating that these features were phylogenetically conserved in the Archosauria. The present observations suggest that the accumulation of yolk materials was controlled by the intrinsic and extrinsic pathways as well as by the activity of follicular cells. These results might also support a sibling relationship of the Testudinidae with the Archosauria and not with all extant reptiles.

scholarly journals Submicroscopic structure of canine articular cartilage

2012 ◽  
Vol 49 (No. 6) ◽  
pp. 207-216 ◽  
Author(s):  
D. Horky ◽  
F. Tichy
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Articular Cartilage ◽  
Collagen Fibrils ◽  
Granular Endoplasmic Reticulum ◽  
Pericellular Matrix ◽  
Submicroscopic Structure ◽  
Intercellular Matrix ◽  
Cartilage Layer ◽  
Transport Vesicles

Canine articular cartilage was studied in male dogs at age 1, 4, 5 and 8 years. Samples collected from four hip joints and two humeral joints in each age category were processed by standard methods to be examined by scanning and transmission electron microscopy. The cartilage of both joints was similar in structure. In the superficial cartilage layer of one-year-old animals, individual spindle-shaped chondrocytes in the extracellular matrix were, together with associated collagen fibrils, located parallel to the surface. When viewed by scanning electron microscopy, they were distinctly prominent above the surrounding surface. Changes in the thickness and arrangement of both the chondrosynovial membrane and intercellular matrix were apparent in the 4-, 5- and 8-year-old animals, indicating the onset or progression of an osteoarthritic process. The middle cartilage layer in young animals showed elliptical chondrocytes occurring in pairs. The voluminous cytoplasm contained a great amount of granular endoplasmic reticulum, a large Golgi complex and numerous transport vesicles. The pericellular matrix, up to 1 µm thick, was composed of aperiodic fibrils. In the old animals the pericellular matrix was absent and was replaced by thick collagen fibrils with a marked periodicity. The deep cartilage layer in young dogs included groups of three to four chondrocytes situated in a common territory. The cytoplasm contained distinct bundles of intermediary filaments. The pericellular matrix occasionally formed septa between adjoining cells. The intracellular matrix included bundles of collagen fibrils arranged in a matted structure. In the old animals aggregation of chondrocytes into groups almost disappeared. The cytoplasm showed only short cisternae of granular endoplasmic reticulum, small numbers of mitochondria and transport vesicles, frequent lipid droplets and small glycogen deposits. The intercellular matrix consisted of only short collagen fibrils with no distinct periodicity.

scholarly journals The thyroid "microsomal" antibody revisited. Its paradoxical binding in vivo to the apical surface of the follicular epithelium.

1984 ◽  
Vol 159 (2) ◽  
pp. 577-591 ◽  
Author(s):  
E L Khoury ◽  
G F Bottazzo ◽  
I M Roitt
Keyword(s):  
Autoimmune Thyroid Disease ◽  
Specific Binding ◽  
Follicular Epithelium ◽  
Apical Surface ◽  
Apical Margin ◽  
Follicular Cells ◽  
Thyroid Cells ◽  
Autoimmune Thyroid ◽  
Microsomal Antibody

We have shown that thyroid monolayers derived from the glands of patients with autoimmune thyroid disease have immunoglobulin (Ig) bound to their surface. This appears to have been deposited in vivo rather than during preparation of the monolayers, a view supported by our finding of such deposits on the apical margin of follicular cells in sections cut from these glands and stained with conjugated anti-immunoglobulin. It is likely that these deposits represent specific binding of so-called "microsomal" autoantibodies to the surface of the thyroid cells in vivo since staining of partially disrupted follicles ("half-melons") with Hashimoto serum containing microsomal autoantibodies in the indirect immunofluorescence (IFL) test, localized the antigen on the apical surface of the cells lining the follicular cavity. Thus, paradoxically, although the antigen is relatively inaccessible, autoantibodies do reach and combine with the thyroid surface in vivo and may therefore play a role in pathogenesis.

scholarly journals Expression of Galectin-1 and Galectin-3 in Human Fetal Thyroid Gland

2003 ◽  
Vol 51 (4) ◽  
pp. 479-483 ◽  
Author(s):  
Svetlana B. Savin ◽  
Dubravka S. Cvejić ◽  
Miroslava M. Janković
Keyword(s):  
Thyroid Gland ◽  
De Novo ◽  
Thyroid Tissue ◽  
Follicular Cells ◽  
Thyroid Cells ◽  
Cytoplasmic Staining ◽  
Tissue Organization ◽  
Galectin 3 ◽  
Fetal Thyroid ◽  
Thyroid Epithelium

High levels of expression of galectin-1 and galectin-3, the β-galactoside-binding proteins, have been recently described in malignant thyroid tumors but not in adenomas nor in normal thyroid tissue. However, there are no data about the expression of these galectins during fetal thyroid development. In this study we analyzed immunohistochemically the presence of galectin-1 and galectin-3 in human fetal thyroid glands (16–37 weeks of gestation). Weak to moderate cytoplasmic staining for galectin-1 was observed in follicular cells of all fetal thyroids. Galectin-3 could not be detected in thyroid follicular cells of any fetal thyroid investigated. Both galectins were detected in stromal tissue, but staining for galectin-1 was more intense. The absence of galectin-3 in thyroid cells during fetal development suggests that galectin-3 is expressed de novo during malignant transformation of thyroid epithelium, and that galectin-1 could be considered an oncofetal antigen. The results obtained indicated potential roles for galectin-1 and galectin-3 during the investigated period of human fetal thyroid gland development. Both galectins might participate in developmental processes regarding stromal fetal thyroid tissue organization, whereas galectin-1 might have a function in thyroid epithelium maturation.

Modification of Pineal Ultrastructure by Exogenous Hormones

1967 ◽  
Vol 25 ◽  
pp. 170-171
Author(s):  
R. A. Turner ◽  
A. E. Rodin ◽  
D. K. Roberts
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Rough Endoplasmic Reticulum ◽  
Estradiol Benzoate ◽  
Female Rats ◽  
List Type ◽  
Type Number ◽  
Pregnant Rats ◽  
Gonadal Atrophy ◽  
Pineal Ultrastructure

There have been many reports which establish a relationship between the pineal and sexual structures, including gonadal hypertrophy after pinealectomy, and gonadal atrophy after injection of pineal homogenates or of melatonin. In order to further delineate this relationship the pineals from 5 groups of female rats were studied by electron microscopy:ControlsPregnant ratsAfter 4 weekly injections of 0.1 mg. estradiol benzoate.After 8 daily injections of 150 mcgm. melatonin (pineal hormone).After 8 daily injections of 3 mg. serotonin (melatonin precursor).No ultrastructural differences were evident between the control, and the pregnancy and melatonin groups. However, the estradiol injected animals exhibited a marked increase in the amount and size of rough endoplasmic reticulum within the pineal cells.

Copper Localization in Cirrhotic Rat Liver by Scanning Electron Microscopy

1969 ◽  
Vol 27 ◽  
pp. 38-39 ◽  
Author(s):  
J. C. Russ ◽  
E. McNatt
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Copper Acetate ◽  
Lead Citrate ◽  
Dense Bodies ◽  
Transmission Electron ◽  
Electron Mode ◽  
Scanning Electron

In order to study the retention of copper in cirrhotic liver, rats were made cirrhotic by carbon tetrachloride inhalation twice weekly for three months and fed 0.2% copper acetate ad libidum in drinking water for one month. The liver tissue was fixed in osmium, sectioned approximately 2000 Å thick, and stained with lead citrate. The section was examined in a scanning electron microscope (JEOLCO JSM-2) in the transmission electron mode.Figure 1 shows a typical area that includes a red blood cell in a sinusoid, a disse, and a portion of the cytoplasm of a hepatocyte which contains several mitochondria, peribiliary dense bodies, glycogen granules, and endoplasmic reticulum.

Morphological and biochemical analyses of changes in rat hepatocytes related to wine and ethanol consumption

1984 ◽  
Vol 42 ◽  
pp. 232-233
Author(s):  
S.M. Geyer ◽  
C.L. Mendenhall ◽  
J.T. Hung ◽  
E.L. Cardell ◽  
R.L. Drake ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Enzyme Activity ◽  
Malic Enzyme ◽  
Smooth Endoplasmic Reticulum ◽  
Rat Hepatocytes ◽  
Mature Male ◽  
Treatment Groups ◽  
Malic Enzyme Activity ◽  
Biochemical Analyses

Thirty-three mature male Holtzman rats were randomly placed in 3 treatment groups: Controls (C); Ethanolics (E); and Wine drinkers (W). The animals were fed synthetic diets (Lieber type) with ethanol or wine substituted isocalorically for carbohydrates in the diet of E and W groups, respectively. W received a volume of wine which provided the same gram quantity of alcohol consumed by E. The animals were sacrificed by decapitation after 6 weeks and the livers processed for quantitative triglycerides (T3), proteins, malic enzyme activity (MEA), light microscopy (LM) and electron microscopy (EM). Morphometric analysis of randomly selected LM and EM micrographs was performed to determine organellar changes in centrilobular (CV) and periportal (PV) regions of the liver. This analysis (Table 1) showed that hepatocytes from E were larger than those in C and W groups. Smooth endoplasmic reticulum decreased in E and increased in W compared to C values.

Triple Fixation For Electron Microscopy

1968 ◽  
Vol 26 ◽  
pp. 90-91 ◽  
Author(s):  
M. A. Hayat
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Electron Beam ◽  
Plasma Membrane ◽  
Myelin Sheath ◽  
Good Deal ◽  
Granular Structure ◽  
Oxidizing Agent ◽  
Fixation Technique ◽  
Large Clusters

Potassium permanganate has been successfully employed to study membranous structures such as endoplasmic reticulum, Golgi, plastids, plasma membrane and myelin sheath. Since KMnO4 is a strong oxidizing agent, deposition of manganese or its oxides account for some of the observed contrast in the lipoprotein membranes, but a good deal of it is due to the removal of background proteins either by dehydration agents or by volatalization under the electron beam. Tissues fixed with KMnO4 exhibit somewhat granular structure because of the deposition of large clusters of stain molecules. The gross arrangement of membranes can also be modified. Since the aim of a good fixation technique is to preserve satisfactorily the cell as a whole and not the best preservation of only a small part of it, a combination of a mixture of glutaraldehyde and acrolein to obtain general preservation and KMnO4 to enhance contrast was employed to fix plant embryos, green algae and fungi.

Image quality vs data obtainment in biological electron microscopy

1986 ◽  
Vol 44 ◽  
pp. 42-43
Author(s):  
J. E. Johnson
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Electron Beam ◽  
Image Quality ◽  
High Speed ◽  
Early Period ◽  
Early Years ◽  
Fluorescent Screen ◽  
Embedding Medium

In the early years of biological electron microscopy, scientists had their hands full attempting to describe the cellular microcosm that was suddenly before them on the fluorescent screen. Mitochondria, Golgi, endoplasmic reticulum, and other myriad organelles were being examined, micrographed, and documented in the literature. A major problem of that early period was the development of methods to cut sections thin enough to study under the electron beam. A microtome designed in 1943 moved the specimen toward a rotary “Cyclone” knife revolving at 12,500 RPM, or 1000 times as fast as an ordinary microtome. It was claimed that no embedding medium was necessary or that soft embedding media could be used. Collecting the sections thus cut sounded a little precarious: “The 0.1 micron sections cut with the high speed knife fly out at a tangent and are dispersed in the air. They may be collected... on... screens held near the knife“.

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