Sulfated proteoglycan accumulation during development of the embryonic chick limb bud studied by electron microscopic autoradiography

Development ◽  
1980 ◽  
Vol 55 (1) ◽  
pp. 195-209
Author(s):  
Moira Cioffi ◽  
Robert L. Searls ◽  
S. Robert Hilfer
Keyword(s):  
Extracellular Space ◽  
Limb Bud ◽  
Proteoglycan Synthesis ◽  
High Concentration ◽  
Electron Microscopic ◽  
Electron Microscopic Autoradiography ◽  
Intracellular Space ◽  
Muscle Region ◽  
Significant Difference ◽  
Silver Grains

Cartilage cells are characterized by a high concentration of extracellular sulfated proteoglycan. Electron microscopic autoradiography was used to compare the incorporation of sulfate into proteoglycan by limb-bud chondrogenic and myogenic cells. From stage 19 to stage 21 there was no significant difference between the cartilage- and muscle-forming regions in the number of silver grains over either the extracellular space or the intracellular space. From stage 22 to 25 the number of extracellular silver grains was significantly greater in the chondrogenic region than in the myogenic region, but the number of intracellular silver grains was the same. Since most of the silver grains were intracellular, no significant difference in the total number of grains was found between the two tissues. Stage-26 and -27 embryos showed a significantly greater number of silver grains over both the cells and the extracellular space in the cartilage region than in the muscle region. Thus, the first step of cartilage differentiation involves a decrease in the extracellular deposition of sulfated proteoglycan in the myogenic region rather than an increase in deposition in the chondrogenic region between stage 22 and 25. After stage 25 there is an increase in sulfated proteoglycan synthesis in the chondrogenic region relative to the myogenic region.

RENAL UPTAKE AND METABOLISM OF ADRENOCORTICOTROPHIN ANALOGUES IN THE RAT: AN AUTORADIOGRAPHIC STUDY

1977 ◽  
Vol 74 (1) ◽  
pp. 23-35 ◽  
Author(s):  
J. R. J. BAKER ◽  
H. P. J. BENNETT ◽  
R. A. CHRISTIAN ◽  
C. McMARTIN
Keyword(s):  
Autoradiographic Study ◽  
Proximal Tubules ◽  
Tyrosine Residue ◽  
Electron Microscopic ◽  
Electron Microscopic Autoradiography ◽  
Renal Uptake ◽  
Endocytotic Vesicles ◽  
Silver Grains ◽  
Uptake And Metabolism

Renal resorption of tritiated adrenocorticotrophin analogues was studied in the rat using light microscopic and quantitative electron microscopic autoradiography. The synthetic corticotrophins used were Synacthen (corticotrophin-(1–24)-tetracosapeptide) and C 41795-Ba ([D-Ser1,Lys17,Lys18]-corticotrophin-(1–18)-octadecapeptide amide), the tetracosapeptide being tritiated in either the tyrosine residue of position 2 or 23 or the phenylalanine of position 7 and the octadecapeptide in the tyrosine of position 2. Inspection of autoradiographs showed that peptides injected intravenously were resorbed into proximal tubules by endocytosis to produce vesicles whose radiolabel later appeared in lysosomes, a route previously elucidated for other peptides and proteins. The use of two techniques for analysis of electron microscopic autoradiographs, however, suggested that apical tubules also acquire label and are in some way involved in the transfer of resorbed labelled material from endocytotic vesicles to lysosomes. In addition, the autoradiographic analyses revealed that the duration of lysosomal labelling depends upon the position of tritium in the chain. Thus, when the CO2H-terminus of Synacthen was labelled, silver grains were more transiently associated with lysosomes than was the case when the NH2-terminal or core regions were tritiated, indicating a greater resistance of these portions of the peptide to attack by intracellular peptidase. The label from the chemically protected C 41795-Ba was also less readily expelled from the lysosomes of the proximal tubules.

Incorporation of tritiated cytochalasin B into ectodermal explants of the amphibian gastrula

Development ◽  
1976 ◽  
Vol 36 (1) ◽  
pp. 209-223
Author(s):  
M. M. Perry ◽  
G. G. Selman ◽  
J. Jacob
Keyword(s):  
Cytochalasin B ◽  
Superficial Layer ◽  
Electron Microscopic ◽  
Cytoplasmic Matrix ◽  
Electron Microscopic Autoradiography ◽  
Triturus Alpestris ◽  
Cell Fractions ◽  
Cellular Components ◽  
Silver Grains ◽  
Compact Spheres

Ectodermal explants from gastrulae of Triturus alpestris were exposed to tritiated cytochalasin B (5 and 10µg/ml) for ½–2½ h. The flat explants failed to heal into compact spheres and the component cells gradually rounded up. Radioactivity in the fixed and sectioned material was analysed by light and electron microscopic autoradiography. Silver grains were found predominantly over the yolk platelets, but were also scattered over other cellular components. Areas containing pigment granules or the feltwork material, present in the apices of dissociating cells of the superficial layer, exhibited higher activity than areas containing mitochondria or cytoplasmic matrix. Lipid droplets and nuclei showed comparatively little activity. The results are discussed in relation to previous findings on the uptake of tritiated cytochalasin D by cell fractions.

scholarly journals Nuclear and Extranuclear Estrogen Binding Sites in the Rat Forebrain and Autonomic Medullary Areas

Endocrinology ◽  
2008 ◽  
Vol 149 (7) ◽  
pp. 3306-3312 ◽  
Author(s):  
Teresa A. Milner ◽  
Laura S. Lubbers ◽  
Stephen E. Alves ◽  
Bruce S. McEwen
Keyword(s):  
Subcellular Location ◽  
Brain Regions ◽  
Rostral Ventrolateral Medulla ◽  
Ventrolateral Medulla ◽  
Solitary Tract ◽  
Electron Microscopic ◽  
Electron Microscopic Autoradiography ◽  
Ca1 Region ◽  
Rat Forebrain ◽  
Silver Grains

Immunocytochemical studies have shown that nuclear and extranuclear estrogen receptors (ERs) are present in several extrahypothalamic brain regions. The goal of this study was to determine the subcellular location of functional ERs, particularly extranuclear ERs, by demonstrating 125I-estradiol binding in the rat forebrain and medullary sections prepared for light and electron microscopic autoradiography. Some sections were immunocytochemically labeled with the catecholamine-synthesizing enzyme, tyrosine hydroxylase (TH), prior to the autoradiographic procedure. By light microscopy, dense accumulations of silver grains denoting 125I-estradiol binding were observed over cells in the ventromedial and arcuate hypothalamic nuclei, amygdala, and nucleus of the solitary tract. In sections labeled for TH, large accumulations of silver grains were admixed with TH-labeled processes in the medial nucleus of the amygdala and over TH-labeled perikarya in the medial and commissural nucleus of the solitary tract. Electron microscopic analyses were focused on the rostral ventrolateral medulla and the hippocampal CA1 region, two regions previously shown to have extranuclear ERs. In the rostral ventrolateral medulla, silver grains indicative of 125I-estradiol binding were found within a few large terminals, affiliated with mitochondria. In the hippocampus, autoradiographic silver grains denoting 125I-estradiol binding were associated with mitochondria in dendritic shafts or were near synaptic specializations on dendritic spines. These patterns of silver grain labeling were not seen in sections from rats that received 125I-estradiol combined with cold estradiol. The association of 125I-estradiol binding with pre- and postsynaptic profiles supports a functional role for nonnuclear ERs in brain.

45Calcium localization in islets of Langerhans, a study by electron-microscopic autoradiography

1976 ◽  
Vol 21 (2) ◽  
pp. 415-422
Author(s):  
S.L. Howell ◽  
M. Tyhurst
Keyword(s):  
B Cells ◽  
Islets Of Langerhans ◽  
Dominant Role ◽  
Cytosolic Calcium ◽  
High Energy ◽  
Electron Microscopic ◽  
Electron Microscopic Autoradiography ◽  
Pancreatic B Cells ◽  
Storage Granules ◽  
Silver Grains

Attempts were made to localize the sites of uptake of 45calcium in B cells of islets of Langerhans by electron-microscopic autoradiography. Despite the potential sources of error inherent in the partial loss of radioactivity during fixation, and in the relatively high energy of emission of this isotope, distribution of silver grains differed signficantly from random in all experiments. Grains were concentrated over mitochondria and to a lesser extent over storage granules. Incubation of islets in the presence of 10 mM glucose and isobutylmethyl-xanthine before fixation and autoradiography resulted in a small but not statistically significant reduction in silver grains associated with the mitochondria. These results further indicate a dominant role of mitochondria in the regulation of cytosolic calcium concentrations in pancreatic B cells.

scholarly journals Synthesis of CDP-diacylglycerol by rat liver rough microsomes as visualized by electron microscopic autoradiography: relationship to GTP-stimulated membrane fusion.

1991 ◽  
Vol 39 (3) ◽  
pp. 363-372 ◽  
Author(s):  
M Jolicoeur ◽  
F W Kan ◽  
J Paiement
Keyword(s):  
Membrane Fusion ◽  
Rat Liver ◽  
Freeze Fracture ◽  
Phospholipid Metabolism ◽  
Electron Microscopic ◽  
Electron Microscopic Autoradiography ◽  
Autoradiographic Analysis ◽  
Freeze Fracture Electron Microscopy ◽  
Layer Chromatography ◽  
Silver Grains

Using detergent-free conditions of incubation for the analysis of liponucleotide synthesis, we compared GTP-dependent formation of CDP-diacylglycerol (CDP-DG) and membrane fusion in RNA-depleted rough microsomes from rat liver. After incubation of stripped rough microsomes (SRM) in the presence of GTP and [5-3H]-CTP, radioactivity was recovered in lipid extracts and identified by thin-layer chromatography as a single spot which co-migrated with CDP-DG. The nucleotide requirement for CDP-DG synthesis and that for membrane fusion were observed to be identical. We next carried out an electron microscopic autoradiographic analysis on incubated membranes to determine the site of incorporation of [5-3H]-CTP. Silver grains were observed directly over the unilamellar membranes of natural vesicles. In confirmation of the biochemical data, quantitation of silver grain density indicated more grains over membranes incubated in the presence of GTP than over those incubated in the absence of this nucleotide. For membranes incubated in the presence of GTP, the grain density was similar over fused and unfused membranes in the same preparation. When SRM were incubated with the enzyme co-factors required for synthesis of phosphatidylinositol, a GTP-independent membrane fusion was observed by both transmission and freeze-fracture electron microscopy. Together with the biochemical and autoradiographic data, this suggests that phospholipid metabolism may be activated by GTP and lead to the fusion of RER membrane.

Localization of Gallium-67 in Peritoneal Cells by Electron Microscopic Autoradiography

1973 ◽  
Vol 31 ◽  
pp. 404-405
Author(s):  
D. C. Swartzendruber ◽  
Norma L. Idoyaga-Vargas
Keyword(s):  
Clinical Trials ◽  
Soft Tissue ◽  
Tumor Tissue ◽  
Soft Tissue Tumors ◽  
Clinical Usefulness ◽  
Electron Microscopic ◽  
Normal Cells ◽  
Electron Microscopic Autoradiography ◽  
Peritoneal Cells ◽  
Gallium 67

The radionuclide gallium-67 (67Ga) localizes preferentially but not specifically in many human and experimental soft-tissue tumors. Because of this localization, 67Ga is used in clinical trials to detect humar. cancers by external scintiscanning methods. However, the fact that 67Ga does not localize specifically in tumors requires for its eventual clinical usefulness a fuller understanding of the mechanisms that control its deposition in both malignant and normal cells. We have previously reported that 67Ga localizes in lysosomal-like bodies, notably, although not exclusively, in macrophages of the spocytaneous AKR thymoma. Further studies on the uptake of 67Ga by macrophages are needed to determine whether there are factors related to malignancy that might alter the localization of 67Ga in these cells and thus provide clues to discovering the mechanism of 67Ga localization in tumor tissue.

Distribution of newly formed hepatic glycogen in adrenalectomized rats as observed by radioautography after injection of 3H-galactose

1984 ◽  
Vol 42 ◽  
pp. 228-229
Author(s):  
J. E. Michaels ◽  
J. T. Hung ◽  
E. L. Cardell ◽  
R. R. Cardell
Keyword(s):  
Glycogen Synthesis ◽  
Hepatic Glycogen ◽  
Electron Microscopic ◽  
Routine Procedures ◽  
Silver Grains ◽  
Synthetic Glucocorticoid ◽  
Adrenalectomized Rats

In order to study early events of glycogen synthesis, we have used adrenalectomized (ADX) rats fasted overnight and injected with the synthetic glucocorticoid dexamethasone (DEX) to stimulate glycogen synthesis. Rats were given DEX 0-5 hr prior to sacrifice and injected with 2 mCi 3H-galactose 1 hr prior to sacrifice. Liver was prepared for light (LM) and electron microscopic (EM) radioautography by routine procedures.The concentration of silver grains over hepatic cytoplasm was measured in LM radioautographs using a Zeiss Videoplan. The hepatocytes were categorized as unlabeled if no silver grains (gr) were present, lightly labeled (<10gr/100 μm2 cytoplasm) or intensely labeled (>10 gr/1002 μm cytoplasm). Although very few hepatocytes showed heavy labeling after 1 hr treatment with DEX, by 2 hr after DEX treatment 8% of the cells distributed throughout the lobule were intensely labeled.

Scanning electron microscopic study of collagen fibrillogenesis and extracellular compartmentalization in the chick embryo tendon

1986 ◽  
Vol 44 ◽  
pp. 208-209
Author(s):  
Grace C.H. Yang
Keyword(s):  
Chick Embryo ◽  
Extracellular Space ◽  
Fibroblast Cell ◽  
Collagen Fibrils ◽  
Electron Microscopic ◽  
Voltage Electron ◽  
Scanning Electron Microscopic Study ◽  
Microscopic Studies ◽  
And Function

The size and organization of collagen fibrils in the extracellular matrix is an important determinant of tissue structure and function. The synthesis and deposition of collagen involves multiple steps which begin within the cell and continue in the extracellular space. High-voltage electron microscopic studies of the chick embryo cornea and tendon suggested that the extracellular space is compartmentalized by the fibroblasts for the regulation of collagen fibril, bundle, and tissue specific macroaggregate formation. The purpose of this study is to gather direct evidence regarding the association of the fibroblast cell surface with newly formed collagen fibrils, and to define the role of the fibroblast in the control and the precise positioning of collagen fibrils, bundles, and macroaggregates during chick tendon development.

scholarly journals STUDIES ON MICROPEROXISOMES II. A CYTOCHEMICAL METHOD FOR LIGHT AND ELECTRON MICROSCOPY

1972 ◽  
Vol 20 (12) ◽  
pp. 1006-1023 ◽  
Author(s):  
ALEX B. NOVIKOFF ◽  
PHYLLIS M. NOVIKOFF ◽  
CLEVELAND DAVIS ◽  
NELSON QUINTANA
Keyword(s):  
Endoplasmic Reticulum ◽  
Guinea Pig ◽  
Lipid Droplets ◽  
Smooth Endoplasmic Reticulum ◽  
Light And Electron Microscopy ◽  
Distal Tubule ◽  
Striking Difference ◽  
High Concentration ◽  
Electron Microscopic ◽  
Pig Kidney

A modification of the Novikoff-Goldfischer alkaline 3,3'-diaminobenzidine medium for visualizing peroxisomes is described. It makes possible light microscopic as well as electron microscopic studies of a recently described class of peroxisomes, the microperoxisomes. Potassium cyanide (5 x 10–3 M) is included in the medium to inhibit mitochondrial staining, the pH is 9.7 and there is a high concentration of H2O2 (0.05%). Two cell types have been chosen to illustrate the advantages of the new procedure for demonstrating the microperoxisomes: the absorptive cells in the human jejunum and the distal tubule cells in the guinea pig kidney. Suggestive relations of microperoxisomes and lipid are described in the human jejunum. The microperoxisomes are strategically located between smooth endoplasmic reticulum that radiates toward the organelles and contains lipid droplets and "central domains" of highly specialized endoplasmic reticulum which do not show the lipid droplets. The microperoxisomes are also present at the periphery of large lipid-like drops. In the guinea pig kidney tubule there is a striking difference between the thick limb of Henle and distal tubule. The distal tubule has a population of cells with large numbers of microperoxisomes readily visible by light microscopy; these cells are not present in the thick limb of Henle. Other differences between the two are also described.

The deposition of Hg203-chlormerodrin in experimental brain tumors

1971 ◽  
Vol 35 (3) ◽  
pp. 303-308 ◽  
Author(s):  
Tatsuya Kobayashi ◽  
Louis Bakay ◽  
Joseph C. Lee
Keyword(s):  
Brain Tumors ◽  
Tumor Cells ◽  
Normal Brain ◽  
Intracranial Tumors ◽  
Electron Microscopic ◽  
Electron Microscopic Autoradiography ◽  
Content Type ◽  
Meningeal Tumors ◽  
Vacuolar System ◽  
Fine Print

✓ The deposition of Hg203-chlormerodrin was studied in intracranial tumors in mice induced by implantation of 20-methyl cholanthrene by tissue assay, as well as light microscopic and electron microscopic autoradiography. The investigations were carried out in astrocytomas, glioblastomas, and meningeal tumors. The chlormerodrin content of the tumors exceeded that of normal brain with a significant tumor/brain ratio ranging from 5.8 to 22.5. It was found that the chlormerodrin molecule becomes rapidly incorporated in the tumor cells, with a preference for that portion of the cytoplasm associated with the vacuolar system.

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