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

Normal young pigs were injected intravenously with azo dye Evans blue, which is preferentially and consistently taken up by focal areas in the aorta known to be areas of enhanced permeability. Ferritin was intravenously injected into these animals, and its uptake was quantitated at the electron microscope level at 1, 5 and 15 min after administration. The number of vesicles, large inclusions or vacuoles, and junctions, both labelled and unlabelled, were counted in areas of normal and enhanced permeability. The results have revealed that the number of ferritin grains per vesicle is the same in both areas. However, the percentage of vesicles containing ferritin is significantly higher in areas of enhanced permeability.
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PMID:Structural correlates of arterial endothelial permeability in the Evans blue model. 20 Sep 55

In the carotid air drying model of arterial endothelial injury in the stressed rat, endothelium does not always regenerate over the zone of intimal thickening; instead, a layer of modified smooth muscle cells appears to form a temporary luminal surface. We examined the properties of these luminal smooth muscle cells in injured right carotid arteries from stressed rats at intervals up to 2 months by light, scanning electron, and transmission electron microscopy. Before perfusion fixation, selected animals were given injections of Evans blue dye, ferritin, or horseradish peroxidase. Unlike adjacent endothelium, the luminal smooth muscle cells most closely resembled neighboring intimal smooth muscle cells, lacked morphologic characteristics of normal endothelium, and did not stain with rabbit antibody to rat factor viii. Unlike normal mature endothelium, this layer did not exclude horseradish peroxidase, Evans blue, or ferritin. These data demonstrate that a nonthrombogenic layer composed of modified smooth muscle cells can appear at the luminal surface of a zone of injury-induced myointimal thickening; however, this layer does not form a permeability barrier to large molecules.
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PMID:A morphologic and permeability study of luminal smooth muscle cells after arterial injury in the rat. 35 25

Patients with widespread neuroblastoma (NB) frequently have elevated serum ferritin levels, and recently anti-NB effects of the iron chelator deferoxamine (DFO) have been reported. We have investigated the effect of DFO on human bone marrow NB cells from two untreated children with Evans Stage IV disease. DFO treatment caused dose- and time-dependent cytotoxicity of NB cells, with maximal killing at exposure to 50 micron DFO for 72 h. Cytotoxicity was prevented by cotreatment with stoichiometric amounts of iron salts and reversible by removal of DFO or addition of iron salts within 48 h of treatment. Additionally, DFO inhibited clonal growth of human bone marrow NB cells in methylcellulose in a time- and dose-dependent manner. These effects were also prevented by cotreatment with iron salts. Thus, DFO has potent antitumor effects on human NB cells which appear to be related to iron deprivation. DFO should be considered for further preclinical evaluation as an anti-NB agent.
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PMID:Deferoxamine inhibition of human neuroblastoma viability and proliferation. 319 93

Three purported means by which large solutes may penetrate the blood-brain barrier are: permeabilized tight junctions; vesicular transport; or channel formation across cerebral blood vessels. The role of vesicular transport has been questioned, in part, because many cytoplasmic vesicles are induced by aldehyde fixation. Cryofixation reduces this artefact and was used to see structural changes in frog cerebral endothelium made permeable to plasma solutes after perivascular exposure to hyperosmotic (3 M) urea, or injury with a cold probe (-50 degrees C). Some control and experimental frogs were made hypothermic so as to inhibit endocytosis and autolytic changes. The brains of some untreated controls were immerse-fixed in aldehydes. Other controls and all other brains of normothermic or hypothermic animals were rapidly frozen, then substituted with acetone-fixative. The interendothelial tight junctions separate partially or completely, after hyperosmotic exposure, in one third of the junctions. Blood-borne ferritin and Evans blue pass through some of the patent junctions. Junctional opening is caused by cell shrinkage, because the perimeter/area ratio of individual endothelial cells in the hyperosmotic group is significantly greater than in the control, due to a decreased area. Large 0.08-0.32-micron-wide invaginations or pits of the endothelial cell membrane characterize both cryofixed and aldehyde-fixed vessels. The pits often appear as isolated vesicles in the cytoplasm, but serial sections reveal that many communicate with either the capillary lumen or subendothelial space. No series of pits opened onto both lumen and space to form a transendothelial channel. The number of vesicles in aldehyde-fixed specimens is about 4 times greater (P less than 0.01) and in the cold injured, cryofixed brain capillary, about two times greater (P less than 0.01), than in the cryofixed control. Hyperosmotic exposure does not increase the number of pits. The permeabilization of anuran cerebral endothelium by hyperosmotic treatment or cold injury is thus by means of an intercellular rather than a transcellular route.
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PMID:Cerebral vessels cryofixed after hyperosmosis or cold injury in normothermic and hypothermic frogs. 325 81

In order to study differences in cell-surface sugars which may be involved in the phagocytic defect in Royal College of Surgeons (RCS) retinas, we have examined the presence or absence of lectin binding to carbohydrates on retinal pigment epithelial (RPE) plasma membranes of dystrophic (RCS-p+) and normal (Long-Evans) rats. A lectin which binds to both sialic acid and N-acetylglucosamine sugar residues, wheat germ agglutinin-ferritin (WGA-fe), was used. The specificity of WGA-fe binding to each sugar was studied by either pre-treating the tissue with neuraminidase enzyme which removes sialic acid residues, or by incubating the WGA-fe lectin with one of the haptens, N-acetylglucosamine. In non-enzyme-treated tissue, RPE cell-surface membranes from RCS retinas were densely labeled with WGA-fe as compared with the labeling on normal RPE, which appeared less dense and patchy in distribution. Wheat germ agglutinin-ferritin labeling in the presence of N-acetylglucosamine was blocked on both RCS and normal RPE surface membranes. After pre-treatment with neuraminidase, WGA-fe labeling on dystrophic RPE membranes was similar to non-enzyme-treated tissue but was enhanced on normal RPE. Labeling was blocked when N-acetylglucosamine was present with the lectin after enzyme pre-treatment. Other lectins which specifically bind to sialic acid, Limulus polyphemus agglutinin-ferritin (LPA-fe) and Limax flavus agglutinin (LFA) demonstrated sparse or no labeling on both RCS and normal RPE membranes. Our data suggests that N-acetylglucosamine residues predominate on RCS and normal RPE cell-surface membranes and that sialic acid binding sites are either not accessible to the lectins or may not be present.
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PMID:Examination of sialic acid binding on dystrophic and normal retinal pigment epithelium. 359 57

The molecular basis for the acquisition of adhesiveness between blastocysts and uterine luminal epithelium is an interesting problem in reproductive biology. It is rather difficult to study implantation-stage blastocysts of mice because during the implantation period each blastocyst becomes lodged within a crypt formed by decidualizing stroma. After trophectoderm adheres to uterine luminal epithelium, it is not possible to flush intact blastocysts from the uterus by standard recovery procedures. By identifying implantation sites with the Evans blue technique and splitting or gently separating the apposed epithelium of finely trimmed sites, it was possible to expose nonadhesive and adhesive trophectoderm to polycationized ferritin (PCF) and a series of ferritin-conjugated lectins. Examination by transmission electron microscopy revealed that both adhesive and nonadhesive trophectoderm bound PCF, concanavalin A, wheat-germ agglutinin, Ricinus communis agglutinin I, and Limulus polyhemus agglutinin, but not Dolicos biflorus agglutinin or peanut agglutinin. Nonadhesive trophectoderm bound succinylated wheat germ agglutinin but adhesive trophectoderm did not. There was no apparent difference in the relative amounts of each lectin bound to adhering and nonadhering cells.
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PMID:Cell surface of mouse blastocysts at the trophectoderm-uterine interface during the adhesive stage of implantation. 373 44

Micro-blood vessels (MBVs), located in the area of edema, were studied in cat brain at various time intervals (1 h, 24 h, 7 days) after cold-lesion injury. Both cold-injured and adjacent gyri were examined for blood-brain barrier (BBB) permeability to i. v. injected horseradish peroxidase (HRP) with circulation times of 40 min and 24 h. Evans blue (EB) was used as a tracer for gross evaluation of the extension of brain edema. Localization of alkaline phosphatase (AP) and binding of cationized ferritin (CF), considered as a marker of anionic sites, were also studied ultrastructurally. Twenty-four hours after cold injury, the extravasated edema fluid, outlined by EB tracer, was observed to be spreading through the white matter (WM) into the adjacent gyrus. At this time, numerous, larger than capillary MBVs, presumably arterioles and venules located in the edematous WM, showed accumulations of HRP injected at the time of the operation, in the basement membrane, in abluminal pits, and in numerous pinocytotic vesicles and vacuoles of endothelial cells (ECs). The animals killed after 24 h with 40 min HRP circulation showed extravasation of HRP tracer in a zone underlying the necrotic cold injury lesion. On the other hand, there was no evidence of an abnormal HRP leakage in the further removed areas of edema in the WM, particularly in the adjacent gyrus.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Ultrastructural observations on the transvascular route of protein removal in vasogenic brain edema. 401 77

The authors have analysed 94 consecutive previously untreated children affected by NB diagnosed at the Giannina Gaslini Children's Hospital in the period January 1972 - December 1981. Age at diagnosis ranged between 1 month - 16 years (median 2 years). Diagnosis was made on histological grounds in 82 cases, on clinical, instrumental and laboratory data in the remaining 12 cases. Evans' staging system was adopted for classifying the disease extent. Patient recruitment was 9.4 cases for year. Female sex slightly prevailed in our series. 17 patients had localized disease (stage I and II), all surviving since 27 - 90 months. 28 children had regional disease (stage III) half of whom are presently alive. Five of the 47 cases with disseminated disease are alive at the time of this study; only one of these 5 can be considered cured, having been followed since more than 4 years. One of the two IV-s stage children survives disease-free at 89 months. 49% of patients were 2-year old or less at diagnosis while only 2 patients were older than 10. Survival was best in children diagnosed under one year of age, lowest in the 2 - 6 year age group. 74% of patients had their primary located in the abdomen (36 in the adrenal, 16 in sympathetic ganglia, 18 in un unidentifable site). Prognosis was worse in these patients compared with those with primary in the thorax, neck and pelvis. The clinical presentation of the disease has been extremely various: most patients had a diagnosis different from the definitive one, and were accordingly treated usually for several weeks or even months. Among laboratory data, urinary catecholamine metabolites, serum LDH and serum ferritin represented the most suitable indices of disease activity. Among immunological studies, none has shown a good correlation with the extent of the disease, nor with the clinical course. Stage I children had only surgery as treatment, while in stage II surgical ablation was followed by short-lasting chemotherapy and radiotherapy in few cases. In stage III and IV more complex multidisciplinary approach was utilized in the attempt to achieve a complete tumor regression. While about a half stage III cases appears curable by these treatment modalities, little impact has been demonstrated by this therapy in widespread disease, although the use of well-designed protocols seems have improved the complete remission rate and the median length of survival.
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PMID:[Neuroblastoma at the Giannina Gaslini Institute. Analysis of 94 cases diagnosed 1972-1981]. 663 42

Horse spleen ferritin (HoSF) reconstituted with small iron cores ranging in size from 8 to 500 iron atoms was studied by magnetic susceptibility and pH measurements to determine when the added Fe3+ begins to aggregate and form antiferromagnetically coupled clusters and also to determine the hydrolytic state of the iron at low iron loading. The Evans NMR magnetic susceptibility measurements showed that at iron loadings as low as 8 Fe3+/HoSF, at least half of the added iron atoms were involved in antiferromagnetic exchange interactions and the other half were present as isolated iron atoms with S = 5/2. As the core size increased to about 24 iron atoms, the antiferromagnetic exchange interactions among the iron atoms increased until reaching the limiting value of 3.8 Bohr magnetons per iron atom, the value present in holo HoSF. HoSF containing eight or more Fe3+ to which eight Fe2+ were added showed that the Fe2+ ions were at sites remote from the Fe3+ and that the resulting HoSF consisted of individual, noninteracting Fe2+ and the partially aggregated Fe3+. pH measurements for core reduction showed that Fe(OH)3 was initially present at all iron loadings but that in the absence of iron chelators the reduced iron core is partially hydrolyzed. Proton induced x-ray emission spectroscopy showed that Cl- is transported into the iron core during reduction, forming a stable chlorohydroxy Fe(II) mineral phase.
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PMID:Iron core formation in horse spleen ferritin: magnetic susceptibility, pH, and compositional studies. 779

We studied the effect of chronic exposure (6 weeks and 6 months) of mice to drinking (tap) water containing 1.76% (0.06 M) aluminum lactate on some cytochemical properties of the blood-brain barrier (BBB). The plasmalemma-bound enzymatic activities of alkaline phosphatase (AP) and Ca(2+)-activated adenosine triphosphatase (Ca(2+)-ATPase) were studied at the ultrastructural level. Anionic sites were localized with cationized ferritin in a pre-embedding procedure and with cationic colloidal gold in a post-embedding procedure applied to brain samples embedded in Lowicryl K4M. Intravenously injected Evans blue and horseradish peroxidase (HRP) were used for evaluation of the functional state of the BBB. The results indicate that chronic exposure to aluminum does not noticeably affect barrier function of the endothelium of cerebral cortex blood microvessels. Focal leakage of larger than capillary microvessels (presumably arterioles and venules) was observed only in a few areas, such as the basal ganglia and amygdaloid nuclei. The localization of both enzymatic activities (AP and Ca(2+)-ATPase) in microvessels remained essentially unchanged. The localization of anionic sites was also unchanged except on the luminal surface of the endothelium of a few blood microvessels located in areas of the brain where leakage of the injected HRP was noted. In these vessels the injected HRP was often attached to the luminal surface of the endothelial cells, suggesting its increased stickiness. These data, compared with our previous observations on brain microvascular endothelial cells growing in vitro, indicate that cytotoxicity of aluminum is evidently less pronounced in the living organism, presumably due to action of detoxicating and regulatory mechanisms.
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PMID:Ultracytochemical studies of the effects of aluminum on the blood-brain barrier of mice. 828 66


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