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)

The dynamics of the toxin Ricinus communis agglutinin II (RCAII or ricin) on cells of a murine lymphoma line (BW5147) and a toxin-resistant variant line (BW5147RicR.3) that is 200 times more resistant than the parent to direct RCAII cytotoxicity were examined using ferritin-conjugated, affinity purified, 125I-labeled RCAII (ferritin-125I-RCAII). Ferritin-125I-RCAII was indistinguishable from native RCAII in quantitative binding and cytotoxicity experiments. When RCAII-sensitive BW5147 and -resistant BW5147RicR.3 cells were labeled with ferritin-125I-RCAII at various toxin concentrations (1--10 microgram/ml), no differences in toxin binding were observed. These same cells were examined by electron microscopy. At low ferritin-125I-RCAII concentrations (1-3 microgram/ml RCAII) where only the parental BW5147 cells were significantly more sensitive to RCAII, toxin receptors were internalized by ferritin-125I-RCAII-induced endocytosis. In parallel experiments, ferritin-125I-RCAII that bound to the resistant BW5147RicR.3 cells remained relatively dispersed or clustered, and there was little evidence of transport into cells via endocytosis. At higher ferritin-125I-RCAII concentrations (greater than 7 microgram/ml RCAII) where both parental and resistant variant cells are sensitive to the cytotoxic effects of RCAII, more ferritin-conjugated toxin was bound, and subsequent endocytosis occurred to a similar degree in both cell types. Endocytosis of ferritin-conjugated concanavalin A was indistinguishable on RCAII-sensitive parental and resistant variant cells at all concentrations tested. The results suggest that a specific defect on the selected BW5147RicR.3 cells prevents RCAII entry into these cells a low toxin concentrations, rendering them more resistant to the cytotoxic effects of RCAII.
 ...
PMID:Dynamics of toxin and lectin receptors on a lymphoma cell line and its toxin-resistant variant using ferritin-conjugated, 125I-labeled ligand. 56 54

The in vitro events of phagocytosis of ferritin and of cationized ferritin by normal eosinophils and the eosinophilic cells of two patients with hypereosinophilic syndrome are described. After one minute of incubation, the cells showed a noticeable pseudopod formation, while after five minutes, ferritin-containing vacuoles were seen in both the normal and the patients' eosinophils. No alterations of the specific granules were observed in cells incubated for 90 minutes or less. Ferritin was observed in the membrane-bound vacuoles, but not in the specific granules of the cells. There was no difference in phagocytic activity of the patients' eosinophils as compared with the normal eosinophils, as well as between phagocytosis of ferritin and of cationized ferritin.
 ...
PMID:Ferritin phagocytosis. 57 89

Ferritin is an iron storage protein which has been shown to be present in blood serum only recently. An immunoradiometric determination of ferritin in 324 subjects with different iron stores is reported. In healthy men and women a ferritin concentration of 131 microgram/l (SD: 1,59) and 67 microgram/l (SD: 1,79) was found respectively. In male and female blood donors as well as patients with iron deficiency and iron overload significant differences of serum ferritin concentration could be demonstrated. In clinical practice the determination of serum ferritin is a valuable method for the estimation of body iron stores.
 ...
PMID:[Ferritin. Radioimmunological determination in serum and clinical significance (author's transl)]. 59 79

Homozygous beta-thalassaemia is a disease in which there is a progressive iron overload from infancy to death in early adulthood. Liver biopsies from 10 patients in various stages of this disease were examined by electron microscopy. A number of round or oval lysosomal structures, containing lamellae different from myelin figures, were seen in all patients, including those with minimal iron overload. Ferritin molecules were seen either in relationship with the lamellae forming arrays, or in paracrystalline arrangement, or with no organized form. There were practically no ferritin molecules in sub-cellular compartments other than cell sap and lysosomes. The density of cell sap ferritin was constant beyond infancy, but the number of iron-laden lysosomes increased with age. The stages in the process of iron seclusion, seen even in advanced phases of iron overload, are described. Ferritin is thought to accumulate in lysosomes by a transmembraneous movement, but other explanations are considered.
 ...
PMID:Ferritin in human liver cells of homozygous beta-thalassaemia: ultrastructural observations. 60 78

Ferritin deposition in the tubular epithelial cells developing after intravenous ferritin injection was investigated in the kidneys of 25 Goldblatt hypertensive rats and of 10 normotensive controls. The phenomenon was detected only in the hypertensive animals. Light microscopic and planimetric data indicate an increased permeability of the glomerular filter and contradict a degenerative damage of the tubular epithelial cells as a primary cause. Ferritin after having crossed the glomerular filter is partly reabsorbed by the tubular epithelium and partly excreted by the urine. The high iron content of the urine and the ferritin detected electrophoretically in it also proves this explanation.
 ...
PMID:Studies on the tubular ferritin-uptake in the kidneys of Goldblatt-hypertensive rats. 61 Jul 6

The present studies were conducted to determine the relationships between iron status and ferritin levels in plasma, liver, and spleen of rats. Rats were fed either iron-adequate or iron-deficient purified diets, and measurements of hemoglobin and plasma and tissue ferritin levels were made at various times during iron depletion and iron repletion. Although mean plasma ferritin concentrations of iron-deficient rats were directionally less than those of iron-adequate rats, these differences were not statistically significant due to high variability among similarly treated animals. During iron repletion plasma ferritin concentrations again were so variable that no significant effect of iron repletion on plasma ferritin concentrations was observed. On the other hand, liver and spleen ferritin concentrations of similarly treated rats were much less variable. Ferritin liver and spleen stores decreased more rapidly than hemoglobin during iron deficiency and were restored more slowly than hemoglobin during iron repletion. There was no evidence of correlation between liver and plasma ferritin concentration. Because of the variable responses of plasma ferritin concentration to iron depletion and repletion and the lack of relationship between plasma and liver ferritin concentrations, it is concluded that plasma ferritin concentration is not a good indicator of iron status in rats.
 ...
PMID:Variable effects of iron status on the concentration of ferritin in rat plasma, liver, and spleen. 62 22

A combined electron microscopic and cytochemical study of the thrombocytes of the mature chicken has demonstrated the existence of two membrane systems, the surface connected system (SCS) and the dense tubular system (DTS). The SCS consists of light tubules and vacuoles which are in continuity with the plasmalemma. A ruthenium red-positive reaction product was observed on the inner surface of this membrane system. Ferritin particles were present in the tubules and the vacuoles of the SCS after the thrombocytes had been incubated in vitro with ferritin. The DTS consisted of the nuclear envelope, the rough-surfaced endoplasmic reticulum, dense tubules and concentric double membrane structures, all of which give a peroxidase-positive reaction. Although actual continuity between the DTS and the SCS of thrombocytes was not observed in this study, close approximation between the two systems was observed at many points. These results are discussed in relation to those from comparable studies of human platelets.
 ...
PMID:Electron microscopic and cytochemical observations on the membrane systems of the chicken thrombocyte. 63 7

The ingestion of ferritin injected into the uterine lumen for 20 min was followed by light and electron microscopy. Uptake occurred on Days 4 to 6, with a distinct peak of activity on Day 5 when blastocysts are present in the uterine lumen. At this time, the antimesometrial cells took up more tracer than those on the mesometrial side. The ferritin was located in various types of organelles which contained acid phosphatase, indicating that the tracer entered the lysosomal system. Ferritin-containing lysosomes were essentially all located in the apical half of the cells at 1 h after the injection, but thereafter were distributed throughout the cell. There appeared to be some digestion of ferritin by 48 h, but no evidence for exocytosis of the tracer at the base of the cells was found with light or electron microscopy.
 ...
PMID:Uptake and fate of ferritin in the uterine epithelium of the rat during early pregnancy. 63 1

A direct radioimmunoassay for ferritin in serum is described in which Bolton and Hunter reagent is used to label ferritin. The detection limit of the assay is 150 pg; 95% reference ranges were found to be 12-200 microgram/l for men and 5-76 microgram/l for women. Ferritin concentrations in patients with iron deficiency anaemia were found to be uniformly low in subjects with uncomplicated iron deficiency but were normal or even raised in subjects with iron deficiency anaemia associated with malignant or inflammatory conditions.
 ...
PMID:Measurement of serum ferritin by radioimmunoassay. 63 7

1. Plasma membranes prepared by pre-incumbation of mouse reticulocytes with 125I, 59Fe-labeled murine transferrin were able to release 59Fe in preference to 125I when incubated in the presence of murine reticulocyte cytosol, demonstrating that the latter mobilized iron which had been dissociated from transferrin. 2. 59Fe in cytosol was associated with at least two components in addition to hemoglobin, a high molecular weight component, identified as ferritin by specific immunoprecipitation, and an as yet unidentified, low molecular weight component of approx 17 00. 3. Ferritin itself, in the absence of added cytosol, was abloe to mobilize 59Fe from s9Fe-labeled reticulocyte plasma membranes. 4. Lysates of reticulocytes synthesized 59Fe-labeled heme when incubated with 59Fe-labeled ferritin. 5. These findings reflect a pathway of iron uptake and incorporation into heme in which ferritin plays an active role.
 ...
PMID:Mobilization of iron from the plasma membrane of the murine reticulocyte. The role of ferritin. 64 5


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