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Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chang cells have been used as a stable model system for the study of cellular iron metabolism. Iron uptake and the stimulation of ferritin synthesis have been studied together with iron incorporation into the ferritin molecule. About 25-30% of the iron taken up by the cells is found in a soluble, non-haem, non-ferritin form which can be chelated by a number of compounds. Ferritin synthesis is inhibited by the presence of desferrioxamine but not by zinc ions.
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PMID:The use of Chang cells cultured in vitro for the investigation of cellular iron metabolism. 117 61

Cellular uptake of ferritin amounting to 0-5 mug/mg cell protein or more can be measured colorimetrically on the basis of ferritin-iron content. 131I-serum albumin, soluble ferritin and aggregated ferritin used in equimolar concentrations are taken up differently by Sarcoma SI80 cells in culture. The net uptakes in 2 h at 37 degrees C are 0-065, 4-3 and 24-7 mug/mg cell protein or 0-93, 8-0 and 45-7 mumol, respectively. Albumin uptake is not inhibited by a 26-fold molar ferritin excess but is significantly inhibited by a 43-fold excess. The transport mechanism of the ferritins differs from that of albumin in that it is significantly inhibitable by 2 times 10(-4) M monoiodoacetate. Soluble ferritin contains small aggregates which are removed by filtration through Millipore membranes of 0-05, 0-1 and 0-22 mum. When the 0-1-mum filtrate is re-examined, uptake is no longer inhibited by iodoacetate. Since it can be inferred from other work that albumin is taken up by pinocytosis and ferritin aggregates by phagocytosis, the difference in susceptibility to inhibition is proposed as a way to distinguish pinocytosis from phagocytosis. Ferritin may form larger visible aggregates in culture medium. The transport mechanism of this aggregated ferritin differs from that of soluble unfiltered ferritin in that it causes concomitant enhancement of albumin uptake. Albumin transported by virtue of this effect becomes partially susceptible to iodoacetate. Thus, in addition to a distinction between pinocytosis and phagocytosis, our data single out 2 forms of albumin transport and 3 forms of ferritin transport.
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PMID:Cellular uptake of soluble and aggregated ferritin: distinction between pinocytosis and phagocytosis. 117 45

Encephalitozoon cuniculi grow within ever-increasing parasitophorous vacuoles (PV) in peritoneal macrophages. The PV boundary membrane conforms to a rich arrangement of blebs; similar, but free vesicles were observed within the PV space. An iron dextran-concanavalin A marker was used to express visually clustered distributions of Con A receptors on the PV boundary blebs and free vesicles; no marker was observed on other membrane surfaces within the PV. These results, combined with the observation that the PV grows while the host cytoplasm decreases in mass, implicate the PV boundary blebs of interiorizing into vesicles by a pinocytic mechanism. Phagocytic vacuoles, secondary lysosomes and pinocytic vesicles were labeled by incubating infected macrophages in minimum essential medium with ferritin. Ferritin readily accumulated in secondary lysosomes and phagocytic vacuoles; however, ferritin was excluded from parasitophorous vacuoles containing E. cuniculi. Acid phosphatase cytochemical reaction product was observed in lysosomes and phagocytic vacuoles; however, parasitophorous vacuoles with vegetative E. cuniculi were always negative.
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PMID:Interactions between Encephalitozoon cuniculi and macrophages. Parasitophorous vacuole growth and the absence of lysosomal fusion. 118 74

A rapid two-stage method has been devised for the separation of different leucocyte populations from human blood. Different cell types can be obtained in an undamaged state and with little contamination. Ferritin and total protein synthesis has been determined by measuring [14C]leucine incorporation in culture media which contain varying amounts of added ferric iron or desferrioxamine. Both ferritin and total protein synthesis is greater in monocytes than in lymphocytes or polymorphs when the basal medium is used. Only monocytes show a consistent increase in ferritin production due to iron stimulation. Ferritin synthesis by monocytes, polymorphs and lymphocytes is inhibited in the presence of desferrioxamine.
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PMID:Ferritin synthesis in lymphocytes, polymorphs and monocytes. 120 Dec 26

This study was designed to determine the content of non-haem iron in the brain as iron deficiency develops in the rapidly growing rat. Rats were provided with either an iron-deficient diet or an identical control diet with added ferrous sulphate starting at 10 d of age and continuing after weaning at 21 d. At 28 d or 48 d of age the deficient animals received 5 mg of iron (iron dextran) i.m. and were placed on the control diet regimen. The deficient animals had a concentration of non-haem iron in the brain that was 27% below the control value at 28 d and 22% below at 48 d. After 14-45 d of iron treatment, the non-haem iron remained depressed, 19-29% below the control means (P less tha 0.05 to 0.001). Ferritin iron in brain also remained depressed, 33-42% below the control means (P less than 0.01). In contrast, haematocrit, liver non-haem iron, and liver ferritin iron, although they were more profoundly depressed in the iron-deficient animals, promptly returned to control values after treatment with iron. Thus, a brief period of severe iron deficiency in the young rat resulted in a deficit of brain iron that persisted in the adult animal despite an adequate intake of iron.
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PMID:Brain iron: persistent deficiency following short-term iron deprivation in the young rat. 120 Dec 39

Distribution of acid phosphatase as a marker enzyme for lysosomes was investigated in the isoprenalin stimulated rat parotid gland. The enzyme was localized in lipofuscin-like bodies as well as in non-discharged granules. The appearance of these bodies was correlated in time to the appearance of smooth vesicles and reduction of the acinar lumen. Ferritin, used as a tracer and introduced into the stimulated gland via cannulated parotid ducts, was found in smooth vesicles, vacuoles and lipofuscin-like bodies throughout the cytoplasm of the acinar cells. Very often ferritin-containing vesicles were found in the vicinity of the Golgi complex. In most cases the vesicles containing ferritin also showed acid phosphatase reaction product. A possible correlation between the lysosomal system and the process of recycling and degradation of membranes in the stimulated gland is discussed.
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PMID:Exocytosis couples to endocytosis of ferritin in parotid acinar cells from isoprenalin stimulated rats. 120 54

A sensitive, specific and precise immunoradiometric assay for ferritin has been developed. Ferritin was measured in the serum of 160 hospital controls, 101 females (118 +/- 9 mug/l) and 59 males (189 +/- 16 mug/l). This difference was statistically significant. In 28 patients with untreated iron deficiency anaemia, serum ferritin concentration (6.1 +/- 0.7 mug/l) was significantly lower than in the controls, but it was within the normal range in 14 cases of polycythaemia vera treated by repeated phlebotomy. In 4 patients with primary haemachromatosis (2884 +/- 56 mug/l), 25 with secondary iron overload states (5702 +/- 1235 mug/l) and 8 with haemolytic anaemia (1612 +/- 605 mug/l), serum ferritin levels were markedly elevated. In 14 cases of transfusional siderosis there was a highly significant correlation between serum ferritin concentration and units of blood transfused. A circadian rhythm in serum ferritin concentration was observed in 7 healthy subjects.
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PMID:Immunoradiometric assay for ferritin in human serum. 121 36

The labelling of negative charges on the cell surface of the developing promastigote forms in Leishmania donovani, L. tropica and L. braziliensis was determined using cationized ferritin and electron microscopy. Ferritin deposits were seen exclusively on the pellicle, since they cannot penetrate the cell membrane. The ferritin particles were distributed in regular rows covering the whole cell surface. The mean diameter of the particles was 8.76 nm and at a magnification of 104.000 an average of 9.8 particles was detected on 1 cm cell surface. Only in the membrane of the proximal part of the reservoir labelling was frequently absent. The possible explanations for this observation were discussed. There was no difference in the pattern size of the ferritin particles or in their number per cm cell surface among the various strains of L. donovani on the one hand or between L. donovani, L. tropica and L. braziliensis on the other.
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PMID:[Comparative electron microscope studies on the labelling Leishmania donovani, Leishmania tropica and Leishmania braziliensis with ferritin (author's transl)]. 121 27

To determine the effects of depleted iron stores on endurance performance and blood lactate concentration, eight active women with normal (> 26 ng/ml) and eight with low (< 12 ng/ml) plasma ferritin concentrations were studied while performing a VO2max and an endurance test (80% VO2max) on a cycle ergometer. The low ferritin group had significantly lower serum iron concentration and transferrin saturation and higher TIBC than the normal ferritin group. Mean VO2max was not significantly different between groups. No significant difference was found in total time to exhaustion during the endurance test for low (23.2 min) and normal (27.0 min) ferritin groups; however, the normal ferritin group exercised 14% longer. Blood lactate concentrations following the VO2max and endurance test did not differ significantly between groups. Food diaries revealed lower daily absorbable iron intake by the low ferritin group compared to the normal ferritin group. Ferritin concentration was significantly related to absorbable iron (r = .72) and total iron (r = .70) intake. The results suggest that women with depleted iron stores who are not anemic may have less endurance, but do not have higher blood lactate during exercise than women with normal iron stores.
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PMID:Effects of low ferritin concentration on endurance performance. 129 7

Localization of ferritin with immunohistochemical staining was carried out in thirty six cases of malignant histiocytosis (MH). The positivity rate for ferritin was 100 per cent. Ferritin was found to exist in the cytoplasm of the tumor cells. Image analysis showed that ferritin level in the well-differentiated histiocytes (1.2314) was higher than that in the atypical histiocytes (0.7181) (P < 0.01). Ten MH patients showed surprising high serum ferritin concentration (1482.3 ng/ml) than that in normal. Our data suggest that ferritin is the tumor associated antigen in MH. The synthesis and release of ferritin by MH tumor cells is the important cause for the high concentration of serum ferritin in patients.
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PMID:[Immunohistochemical localization and serum testing for ferritin in malignant histiocytosis]. 130 85


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