Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A procedure has been developed for the immunoelectron microscopic localization of intracellular antigens on thin-sectioned tissues. The tissues were fixed in a periodate-lysine-paraformaldehyde solution or a formaldehyde-glutaraldehyde combination and embedded in the acrylate-methacrylate mixture, Lowicryl K4M (Polaron), which was polymerized under ultraviolet irradiation at -35 degrees C. Thin sections were mounted on gold grids, immunostained using an indirect method with ferritin-labeled antibodies, and, optionally, counterstained with osmium tetroxide and/or lead citrate and uranyl acetate. The procedure provided good morphologic preservation of the cell architecture in adult and embryonic heart, and skeletal and smooth muscle tissue, as well as nonmuscle cells. At the same time it retained the antigenicities of several contractile proteins, including myosin, tropomyosin, actin, and alpha-actinin. The method has advantages over en bloc staining techniques in that the problem of antibody penetration into the cells is eliminated and careful controls can be performed on adjacent sections. This technique will be useful for localizing, at the ultrastructural level, contractile and other selected proteins in a variety of muscle and non-muscle cells. Details of the new protocol and a description of the results of using antibody against the contractile protein, alpha-actinin, are given.
 ...
PMID:Immunoelectron microscopic localization of alpha-actinin on Lowicryl-embedded thin-sectioned tissues. 388 38

The human promyelocytic cell lines HL-60 can be induced to undergo differentiation to either granulocyte- or macrophage-like cells. We followed the changes in the synthesis and content of ferritin in this and other cell lines during differentiation. Ferritin content of HL-60 cells ranged from 11 to 81 fg/cell, depending on the clone tested. Following exposure to dimethylsulfoxide (DMSO) or retinoic acid (RA) an increase in ferritin and a decrease in total protein synthesis was observed, resulting in increased ferritin content, reaching a peak after 2 days. This increase occurred prior to the appearance of the typical morphological and functional characteristics of mature granulocytes. A correlation was found between concentrations of DMSO effective in inducing differentiation and the increase in ferritin content. Other inducers of granulocyte differentiation had a similar effect, while 12-O-tetradecanoylphorbol-13-acetate (TPA), an inducer of macrophage differentiation, had not. Another human cell line (U-937), which was induced into monocyte-like cells by RA, showed a twofold increase in ferritin content following differentiation. Addition of iron to the culture medium increased ferritin content of both differentiating and non-differentiating cells, but the former responded to lower concentrations of iron. The increase in ferritin during differentiation, however, was not related to an accelerated iron uptake. The present results suggest that changes in the intracellular ferritin of the developing myeloid cells may play a regulating role in the process of maturation of these cells.
 ...
PMID:Changes in cellular ferritin content during myeloid differentiation of human leukemic cell lines. 397 11

1. Ferritin was isolated from human and horse spleen and liver, and apoferritin prepared therefrom. 2. The electrophoretic mobilities of the four apoferritins were determined on polyacrylamide gels and on cellulose acetate strips, and all found to be equal. 3. Homologous ferritins share reactions of identity in immunodiffusion experiments, whereas heterologous ferritins show only partial identity. 4. The subunit molecular weight of each of the apoferritins was determined by polyacrylamide-gel electrophoresis in sodium dodecyl sulphate and by chromatography on agarose columns in 6m-guanidine-HCl. A value of approx. 18500 was found in all cases. The proteins all had sedimentation coefficients of 17-18S. It thus seems that they have identical quaternary structures. 5. The amino acid compositions of the proteins revealed distinct differences both between organs and between species. This was confirmed by analysis of the tryptic peptide patterns, where it was found that about one-third of the peptides were common to the four proteins and the other two-thirds varied from protein to protein. 6. It is concluded that the apoferritins present in the liver and spleen of human and horse are both organ- and species-specific. 7. The apoferritin isolated from the liver of a patient with idiopathic haemochromatosis was identical with normal human liver apoferritin by the criteria described above.
 ...
PMID:The organ-specificity of ferritin in human and horse liver and spleen. 419 84

The ultrastructure of the blood-bubble interface has been studied in rats decompressed experimentally. Subsequent to staining with ruthenium red there was detected by electron microscopy a continuous envelope like layer about 20 nm thick at the bubble-facing surface of the interface. The envelope like structure was visualized also by concanavalin A-ferritin, a glycosyl- and mannosyl residue-recognizing lectin coupled with an electron-dense probe, but the structure was not at all seen by the use of the conventional stains used in electron microscopy, uranyl acetate and lead citrate. No electron-dense layer was discernible on the application of only osmium tetroxide without further staining. The results indicate that material stainable by ruthenium red, and binding concanavalin A (probably a glycoprotein), is concentrated at the blood-bubble interface upon decompression. It is suggested that it plays a role in stabilization of the bubble and in the hematological alterations that are frequently observable in decompression sickness.
 ...
PMID:Ruthenium red staining of blood-bubble interface in acute decompression sickness in rat. 616 82

Much ultrastructural detail is retained in tissue fixed only with aldehydes and subsequently air-dried after suspension in a polyvinyl acetate emulsion. The latter provides an external support only, but permits ultrathin sectioning; thus, an exposure of intracellular contents for potential immunocytochemical reactions is achieved. Sections of unembedded frog retina so prepared have been studied with success. The tissue was incubated first with a rabbit antiserum prepared against gradient purified bovine rod outer segments. Following incubation, reacted sites were labeled with ferritin-conjugated goat anti-rabbit IgG and stained with phosphotungstic acid. Intense labeling of the rod outer segments was clearly achieved, whereas the cone outer segments were without label. Other parts of the retina, including the ellipsoid region of both rods and cones, were also without significant label. These regions provided an intrinsic control for the specificity of the antiserum and established the validity of the general technique.
 ...
PMID:Localization of antibody binding sites in ultrathin sections of unembedded frog retinal tissue. 618 1

Rat liver homogenates in 0.1 M Tris, pH 7.5, were heated to 80 degrees C, cooled immediately, and centrifuged at 24,000 X g, and 7Be2+ was added to the supernatant. Twenty-five per cent of the radioactivity was bound to a single protein. It was purified to homogeneity and identified to be ferritin as judged by different criteria. These were sucrose density gradient centrifugation, electrophoresis in polyacrylamide gel of the native or sodium dodecyl sulfate-treated protein, reactivity to antibodies, isoelectric focusing, and total amino acid composition. Comparative study of the ability of ferritin or apoferritin to bind Cd2+, Zn2+, Cu2+, and Be2+ was conducted by using a gel equilibrium technique, Centifree micropartition technique, and microcentrifuge desalting technique. Ferritin could be saturated with Cd2+ or Zn2+ or Cu2+ but not with Be2+ even after 800 g atoms of Be2+ were bound. None of the bound Be2+ was dialyzable at 4 degrees C in 0.05 Tris acetate buffer, pH 8.5, but at pH 6.5 over 80% of the bound metal ion was dialyzed after 72 h. By contrast, apoferritin bound similar amounts of all four metal ions, some of which were dialyzable. By spectrophotometric titrations at pH 6.5 of Be2+ with sulfosalicylic acid (SSA), BeKDSSA was calculated to be 5.0 X 10(-6) M and by competition of sulfosalicyclic acid and ferritin for Be2+ the BeKDferritin was calculated to be 6.8 X 10(-6) M.
 ...
PMID:Ferritin. Binding of beryllium and other divalent metal ions. 641 22

It was previously shown that cultured mouse peritoneal macrophages ingest anionic derivatives of horseradish peroxidase (HRP) and ferritin by fluid-phase endocytosis and accumulate them in lysosomes. Cationic derivatives were taken up by adsorptive endocytosis and transported to lysosomes but subsequently appeared also in stacked cisternae, tubules, and vesicles of the Golgi complex. In the present investigation, the effect of molecular net charge on the rate of cellular inactivation of a protein was studied. The results demonstrate that anionized HRP was inactivated at a higher initial rate than cationized HRP. This is in agreement with the finding that the cationic protein partly escaped from the digestive compartment of the cells, that means the lysosomes. The effects of phorbol myristate acetate (PMA)--a diterpene ester and a tumor promoter--and monensin--a carboxylic ionophore and a perturbant of the Golgi complex--on fluid-phase endocytosis of HRP and intracellular transport of cationized ferritin (CF) were also studied. PMA stimulated fluid-phase endocytosis of HRP but did not interfere with transport of CF to the Golgi complex. Contrarily, monensin inhibited uptake of HRP and almost totally blocked transport of CF to the Golgi complex. The findings support the idea that membrane and content of endocytic vesicles are treated separately. The content is emptied into lysosomes where macromolecular material normally is degraded. The membrane becomes part of the lysosomal envelope in connection with endocytic vesicle-lysosome fusion. Subsequently, membrane patches are detached from the lysosomes and reutilized. This is at least partly mediated via the Golgi complex and particularly its tubular and vesicular parts. Since the cationic tracers do not bind to the membrane in a stable way, it is not possible to extend the conclusions to individual membrane constituents.
 ...
PMID:Endocytosis, intracellular transport, and turnover of anionic and cationic proteins in cultured mouse peritoneal macrophages. 661 70

Liposomes encapsulating uranyl acetate or ferritin were injected intravenously into mice. At periods of 20 min, 1 h and 4 h post-injection, animals were killed, and livers were excised. Transmission electron micrographs of liver tissue showed association of oligolamellar liposomes with mitochondria for each time period. At 1 h post-injection, an average of one out of ten mitochondria was associated with liposomes. In most cases, the liposomes were clearly enclosed in a cytoplasmic vacuole. Phagocytosis by Kupffer cells as well as fusion with primary lysosomes and inclusion in secondary lysosomes was observed. No difference in intracellular fate was observed when lactosylceramide was incorporated in the liposome bilayers, suggesting that the differences observed in biochemical studies are at the level of liposome-plasma membrane interaction. When liposomes containing uranyl acetate were intravenously injected and hepatocytes were isolated by collagenase perfusion one hour later, transmission EM revealed the presence of liposomes in these cells, in cytoplasmic vacuoles in the cytoplasm and in association with mitochondria. A freeze-fracture-etching analysis of liver tissue excised 20 min after injection of liposomes encapsulating ferritin, further supported the observation that liposomes associate with mitochondria in the liver.
 ...
PMID:Liposomes injected intravenously into mice associate with liver mitochondria. 674 53

An immunohistochemical study was performed to investigate the presence of alpha-1-antitrypsin (alpha 1-AT), alpha-1-antichymotrypsin (alpha 1-ACT), transferrin and ferritin in 32 ameloblastomas and to evaluate the co-expression of these antibodies. Histologically, we recognized the following 6 patterns in the series of 32 ameloblastomas and at least 2 patterns in variable proportions were present in each of our cases: follicular pattern (21 cases, 66%), plexiform pattern (17 cases, 53%), cystic pattern (21 cases, 66%), acanthomatous pattern (10 cases, 31%), granular cell type (2 cases, 6%), and hyalinized stromal pattern (20 cases, 63%). Neoplastic epithelia of cystic pattern were divided into superficial cell, basal cell and whole layer to compare the immunohistochemical localization. The results made on the various patterns of ameloblastomas were as follows: (1) alpha 1-AT positivity in plexiform, cystic and hyalinized stromal patterns was significantly higher than that of alpha 1-ACT (P < 0.05). (2) The incidence of transferrin in follicular and plexiform patterns was markedly higher than that of ferritin in the same patterns (P < 0.025 and P < 0.01). Transferrin strongly stained metaplastic squamous cells of acanthomatous pattern and basal cells of cystic epithelium. (3) Granular cells reacted with transferrin and ferritin. (4) In follicular and acanthomatous patterns, coexpression of alpha 1-AT and alpha 1-ACT, alpha 1-AT and transferrin, or alpha 1-ACT and transferrin was higher than that of another combination. On the other hand, co-expression of alpha 1-AT and transferrin in plexiform and cystic patterns was higher than that of other antibodies. These results of co-expression of 4 antibodies used in the present study, suggest that the histogenesis of follicular and acanthomatous patterns is different from that of plexiform and cystic patterns.
 ...
PMID:Immunohistochemical detection of alpha 1-antitrypsin, alpha 1-antichymotrypsin, transferrin and ferritin in ameloblastoma. 749 17

Release of iron from ferritin in the presence of polyhydroxy metabolites of benzene i.e., hydroquinone (HQ) or 1,2,4-benzenetriol (BT) was studied in acetate buffer, pH 5.6. The release of iron from ferritin was quantitated by monitoring the formation of iron-ferrozine complex. The presence of hydroquinone (330 microM) did not result in the release of iron from ferritin, whereas the same concentration of BT resulted in the release of significant amounts of iron (3.2 microM/min) from ferritin. BT concentration-dependent increase in iron release from ferritin was observed although the increase was not linear with the concentration of BT. Under a N2 atmosphere the presence of BT resulted in the release of iron (2.1 microM/min) from ferritin. The presence of oxyradical scavengers i.e., albumin, catalase or superoxide dismutase significantly inhibited iron release from ferritin by BT. The iron released from ferritin by BT enhanced lipid peroxidation in rat brain homogenate and released aldehydic products from bleomycin-dependent degradation of DNA. Addition of BT to bone marrow lysate resulted in an increase of iron release as a function of time. These studies indicate that BT is a potent reductant of ferric iron of ferritin and also mobilizes and releases iron from ferritin core. The release of iron from bone marrow lysate by BT may be of toxicological significance as this could lead to disruption of intracellular iron homeostasis in bone marrow cells.
 ...
PMID:Release of iron from ferritin by 1,2,4-benzenetriol. 753 77


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>