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

Nuclear magnetic relaxation times T1 and T2 were measured in ferritin solutions at field strengths from 0.04 to 1.5 T. T1 was relatively constant, but 1/T2 increased linearly with field strength, in agreement with earlier MRI observations in the monkey brain. This finding supports the theory that ferritin is responsible for T2 shortening in brain nuclei containing iron. The linear dependence of 1/T2 on magnetic field is unique and not explained by present theories of the magnetic properties of ferritin.
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PMID:T1 and T2 of ferritin at different field strengths: effect on MRI. 133 6

A 55-year-old female with progressed dementia, cerebellar ataxia was reported. There was no family history of the same symptoms although her brothers, sisters and a son showed hypoceruloplasminemia and decrease of the serum copper content. On physical examination, anemia, dementia, dysarthria, torticollis, choreic involuntary movement of respiratory muscles, hyperreflexia in extremities and cerebellar ataxia were noted. Blood analysis revealed microcytic hypochromic anemia, diabetes mellitus, decrease of copper content of the serum and urine. Serum ferritin concentration was increased. Serum ceruloplasmin could not be detected. Biopsy of the liver showed that copper content in the liver was slightly increased and iron content was remarkably increased. On MRI study, dentate nucleus of the cerebellum, the thalamus, the putamen and the caudate nucleus and the liver showed low intensity in both T1 and T2 weighted images. Based on increased iron content in the liver, the radiological findings of the brain suggested deposition of iron in the brain. This deposition was considered as caused by deficiency of function of ceruloplasmin as ferroxidase. This disorder is suggested as a new disease due to ceruloplasmin deficiency different from Wilson's disease.
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PMID:[A case of ceruloplasmin deficiency which showed dementia, ataxia and iron deposition in the brain]. 145 25

What then are the lessons to be learned about prevention and treatment of hemochromatosis? Early diagnosis is essential. The best indicator would be testing of serum iron and total saturation followed by a serum ferritin if elevated. Once these indices are abnormally high, MRI and or a liver biopsy should confirm the stage of the iron over-loaded state. If indeed the patient is not iron-overloaded (normal liver biopsy in the face of high saturation and ferritin level) phlebotomies should be performed until these indices are normal and then maintained at a normal level. This should entail four to six phlebotomies a year. Family members should also be screened and managed in a like manner. HLA typing may be a partially helpful screening device. The abnormal gene is closely linked on chromosome 6 with HLA histocompatibility loci. Now, by means of HLA typing, we can identify heterozygote carriers and homozygous (abnormal) among first degree relatives of patients with hemochromatosis. Unfortunately, HLA typing can only be used within a given family and cannot be used to screen the general population. It is estimated that 70% of hemochromatoics have the antigen HLA-A3; however, so does 28% of the (well) general population. Patients with unexplained cirrhosis, arthritis, liver disease, diabetes, impotency, cardiomyopathy and neurological symptoms should be screened in a like manner. Routine health practice profile chemistries must include a serum iron and iron saturation, and if high followed by a serum ferritin. Once diagnosed, therapy must be maintained with phlebotomy for the life time of the patient.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Hemochromatosis: diagnosis and treatment. 179 61

In the neonate, hyperechoic thickening of the ependyma is believed to be related to ventriculitis. Yet, in our experience, this sign is much more often observed in association with subacute intraventricular hemorrhage (IVH), without infection. Sixty premature neonates were prospectively studied. The observations of transfontanellar sonograms (intracranial hemorrhage, ependymal echogenicity, and ventriculomegaly) were correlated with the results of MRI, lumbar punctures and clinical work-up. Intracranial hemorrhage was detected in 28 patients, and hyperechoic thickening of the ependyma was observed in 21 of them, all of whom had IVH. In 9 of these 21 patients IVH was diagnosed retrospectively thanks to the visualization of the hyperechoic ependyma. In all but one, this sign persisted for at least 2 months after disappearance of other signs of IVH. MRI demonstrated the presence of hemosiderin and ferritin in ependymal or subependymal location only in patients with hyperechoic ependyma. One of our patients had in utero diagnosis of IVH owing to the visualization of the same hyperechoic aspect of the ependyma. Nine of the neonates with hyperechoic ependyma developed ventriculomegaly, and three underwent surgery. Hyperechoic thickening of the ependyma in prematures often results from a subacute IVH. It is related to hemoglobin catabolites which can be detected by MRI. It does not require immediate potentially harmful diagnostic punctures. The presence of this hyperechoic rim allows a retrospective diagnosis of IVH and indicates a clinical and sonographic follow-up in newborns at risk for secondary hydrocephalus.
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PMID:Hyperechoic thickened ependyma: sonographic demonstration and significance in neonates. 749 Dec 14

Eighteen patients with a DSM-III-R diagnosis of obsessive-compulsive disorder (OCD) were imaged by MR and compared to a control group of 18 patients with clinically diagnosed unspecific headaches. Weighted spin-echo sequences were carried out with a 1.5T unit in both axial and coronal planes T1 (TR 700/TE 15 ms) and T2 (TR 2500/TE 15.70). The ferritin distributions in the basal ganglia and in the midbrain were evaluated; in addition, the width of the pars compacta in the midbrain on the basis of the criteria of Braffmann et al. 1988, the widths of the inner subarachnoid spaces on the basis of the ventricular index quotient VIQ (TerBrugge, 1986), and the widths of the outer subarachnoid spaces were conducted. The latter was undertaken by three independent investigators whose results were in agreement with one another. In 12 of the OCD patients (n = 18) there was a total of 25 pathological MRI findings; in the control group there were 6 pathological MRI findings in only 6 of the patients (n = 18). In conclusion pathological changes were found at different locations, but a connection between a specific neuroanatomic system and obsessive-compulsive disorder could not be demonstrated.
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PMID:[Nuclear magnetic resonance tomography findings in obsessive-compulsive disorder]. 799 Oct 8

For the noninvasive liver iron quantification by MRI in human iron overload diseases, fundamental proton relaxation mechanisms were studied in aqueous solutions with ferritin and other iron compounds, in experimentally iron overloaded rats, and in patients with iron overload diseases. MR-relaxation rates as a function of iron concentrations in the range of 0-7.5 mg Fe/g aqueous iron solutions, 0-5.4 mg Fe/g rat liver in vivo, and 0.16-4.9 mg Fe/g human liver in vivo were determined from multi- and sets of single-spin echo sequences (1.5 T imager). As predicted by theory, transverse relaxation rates (1/T2) in aqueous iron solutions, in liver tissue of rats, and in human liver tissue increased linearly with the iron concentration. A preliminary calibration for the liver iron quantification by MRI was performed from in vivo measurements of liver 1/T2-relaxation rates and liver iron quantification by atomic absorption spectroscopy in biopsies from 13 patients. With the single spin-echo method, precise in vivo liver iron quantification in humans also above 2.0 mg Fe/g liver tissue (T2 < 15 ms) should be accomplished on any imager with shortest spin-echo time available, at least TE < 20 ms.
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PMID:Liver iron quantification: studies in aqueous iron solutions, iron overloaded rats, and patients with hereditary hemochromatosis. 799 5

We performed phase III clinical study of AMI-25 (Superparamagnetic iron oxide) for hepatic tumors in 163 cases at the 17 institutions in Japan. In overall evaluation, 141/159 cases (88.7%) were evaluated "useful" or "very useful" for clinical usefulness. For efficacy including the signal to noise ratio (S/N) of liver and the tumor-liver contrast to noise ratio (C/N), 89.6% of hepatocellular carcinomas and 95.0% of metastatic liver cancers were evaluated "effective" or "very effective", respectively. The mild adverse reactions were shown in 10 cases (6.1%), but they disappeared within 25 minutes. The serum iron and ferritin increased and the unsaturated iron binding capacity (UIBC) decreased, but they were showing a tendency to go back to their normal ranges. The AMI-25 (10 mumoles Fe/kg) was proved to be useful and safe contrast agent for the liver tumors in MRI.
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PMID:[Clinical application of AMI-25 (superparamagnetic iron oxide) for the MR imaging of hepatic tumors: a multicenter clinical phase III study]. 812 79

Iron overload is a major cause of morbidity and mortality in thalassemia major patients. All chronic liver diseases may be associated with such endocrine symptoms as diabetes mellitus, testicular failure or hypothyroidism. We studied 15 thalassemic patients (12 men and 3 women; age range: 10-50 years, mean: 22.5 years). All patients received blood transfusions, but only some were treated with iron chelation. Seven patients were splenectomized. MRI was performed with an 0.5 T superconducting magnet, using SE T1- and T2-weighted and IR sequences. We used these data with Bloch's equation to calculate T1 and T2 values. Quantitative analysis was made by calculating signal intensity and relaxation times in 8 hepatic regions of interest: marked reduction in hepatic signal intensity and a negative relationship between T1 and serum ferritin (r = 0.646, p < 0.01) and between T2 and serum ferritin (r = 0.688, p < 0.01) were observed. Moreover, a negative relationship was found between hepatic signal intensity and aspartic aminotransferase (r = 0.524, p < 0.05). Our results confirm the value of MRI in the diagnosis and evaluation of hepatic iron overload but an accurate quantitative analysis can be made only when hepatic iron levels are between 1 and 2 mg/g of liver. Even though it is below statistical significance, the negative relationship between signal intensity and aspartic aminotransferase suggests that hepatic hemochromatosis can influence pituitary-thyroid axis and interfere with peripheral hormone metabolism.
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PMID:[Secondary hepatic hemochromatosis: diagnosis and quantification with 0.5 T magnetic resonance. Value and limitations]. 829 5

The degree to which MRI magnet field strength affects measured transverse relaxation rates (R2) defines a measure termed the field dependent R2 increase (FDRI). We report here the results of in vivo and in vitro experiments that were conducted to evaluate whether FDRI is a potentially useful measure of tissue iron stores. T2 relaxation times were obtained using two clinical MRI instruments operating at 0.5 and 1.5 Tesla, and relaxation rates (R2) were calculated as the reciprocal of T2. The in vivo experiment measured R2 in human brain frontal white matter, caudate nucleus, putamen, and globus pallidus. The FDRI was very highly correlated with published brain iron levels for the four regions examined. The in vitro experiment measured R2 in agarose gel-based phantoms containing physiologic forms and amounts proteins involved in iron storage and transport (ferritin, apoferritin, transferrin, and apotransferrin). Significant field dependence was observed only for the ferritin phantoms. The differences in the R2 values obtained at the two field strengths were striking, and were proportional to the ferritin levels of the phantoms. These studies suggest that FDRI may be a specific measure of tissue ferritin. The quantitative significance of the results to imaging and possible applications to the clinical investigation of pathologic states are discussed.
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PMID:Field dependent transverse relaxation rate increase may be a specific measure of tissue iron stores. 846 61

A retrospective analysis of 158 T1-weighted and T2-weighted MRI scans of normal brains at 0.5 and 1.5 Tesla was performed. Signal intensities in the frontal cortex, caudate nucleus, putamen, and globus pallidus were divided by those of frontal white matter; and these gray/white ratios were correlated with iron concentration, estimated from the anatomical region and age of the patient. Intraregional plots were also made of gray/white ratio versus age for the 1.5 Tesla scans. The changes in both T1-weighted and T2-weighted ratios were consistent with the hypothesis that 1/T1 and 1/T2 vary linearly with iron concentration, and the corresponding coefficients, determined separately from the interregional and intraregional plots, were generally in agreement. Furthermore, the variability of the MRI ratios at 1.5 Tesla was consistent with expected iron variability except for the cortex, in which partial volume errors due to sulci and white matter caused increased variations. The MRI results agreed well with in vitro data on T1 and T2 in tissue specimens and with other MRI studies. When compared with T1 and T2 in ferritin solution, a significant "tissue relaxation enhancement" was found, attributable to slower diffusion and clustering of ferritin in tissue.
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PMID:The quantitative relation between T1-weighted and T2-weighted MRI of normal gray matter and iron concentration. 857 41


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