[Preparation of Prussian Blue@Yeast Catalyst and Its Heterogeneous Fenton Performance]

A novel heterogeneous Fenton catalyst, Prussian blue@yeast (PB@yeast), was prepared via facile self-assembly synthesis. The as-synthesized composite was characterized by field emission scanning electron microscopy (FE-SEM), energy-dispersive spectroscopy (EDS), powder X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). All of the results indicated that PB nanoparticles were uniformly dispersed on the surface of yeasts with stable core-shell morphology. Degradation of the model anionic fluorescent whitening agent CXT indicated that the PB@yeast catalyst presented a synergistic effect of adsorption and heterogeneous Fenton performance. Owing to the high adsorption capacity of yeast, the CXT molecules were easy to move to the active site of the catalyst, promoting the electron transfer between Fe(Ⅲ) and Fe(Ⅱ) and then enhancing the catalytic activity of the Fenton reaction effectively. Furthermore, the yeast support could improve the dispersity and stability of PB nanoparticles, which maintained excellent catalytic activity and stability after being recycled four times.

Phytochemical investigations of Lonchocarpus bark extracts from Monteverde, Costa Rica

The acetone bark extracts of three species of Lonchocarpus from Monteverde, Costa Rica, L. atropurpureus, L. oliganthus, and L. monteviridis, were screened for antibacterial, cytotoxic, and antioxidant activities. L. orotinus extract was antibacterial against Bacillus cereus (MIC = 39 microg/mL), while L. monteviridis exhibited the most antioxidant activity. None of the Lonchocarpus extracts showed cytotoxic activity against MCF-7 cells. Fatty acids and atraric acid were isolated and purified from L. atropurpureus bark, fatty acids and loliolide from L. oliganthus bark, and leonuriside A and beta-D-glucopyranos-1-yl N-methylpyrrole-2-carboxylate from L. monteviridis bark. Atraric acid showed cytotoxic and antimicrobial activities.

Dysplasia features of myelodysplastic syndrome in ethnically Chinese people

OBJECTIVE

It was our aim to study the diagnostic significances of various dysplasia characteristics in myelodysplastic syndrome (MDS).

METHODS

We analyzed 160 cases of primary MDS and a control group including 28 cases of paroxysmal nocturnal hemoglobinuria (PNH), 104 cases of idiopathic thrombocytopenic purpura (ITP), 53 cases of non-severe aplastic anemia (NSAA), 40 cases of megaloblastic anemia and 50 cases of infectious and autoimmune diseases. Peripheral blood smears and bone marrow morphology were reviewed.

RESULTS

There was no significant difference in the occurrence rates of a variety of dysplasias in three lineages among MDS, megaloblastic anemia and PNH; however, changes in qualities and quantities in three lineages between NSAA and MDS were significantly different. ITP and MDS showed statistical differences in multiple changes in myeloid and erythroid cells. Significant differences also existed in multiple changes in erythroid series and megakaryocytes between infectious and autoimmune diseases and MDS. Morphological abnormalities highly related with MDS included multinucleated erythroblasts, ringed sideroblasts, poikilocytosis and gigantocytes, pseudo-Pelger neutrophils, ring-shaped nucleus, and micromegakaryocytes.

CONCLUSIONS

It is difficult to discriminate megaloblastic anemia and PNH from MDS by means of cell morphology. Different dysplasias of MDS have specific diagnostic values.

Brain iron accumulation in unexplained fetal and infant death victims with smoker mothers--the possible involvement of maternal methemoglobinemia

BACKGROUND

Iron is involved in important vital functions as an essential component of the oxygen-transporting heme mechanism. In this study we aimed to evaluate whether oxidative metabolites from maternal cigarette smoke could affect iron homeostasis in the brain of victims of sudden unexplained fetal and infant death, maybe through the induction of maternal hemoglobin damage, such as in case of methemoglobinemia.

METHODS

Histochemical investigations by Prussian blue reaction were made on brain nonheme ferric iron deposits, gaining detailed data on their localization in the brainstem and cerebellum of victims of sudden death and controls. The Gless and Marsland's modification of Bielschowsky's was used to identify neuronal cell bodies and neurofilaments.

RESULTS

Our approach highlighted accumulations of blue granulations, indicative of iron positive reactions, in the brainstem and cerebellum of 33% of victims of sudden death and in none of the control group. The modified Bielschowsky's method confirmed that the cells with iron accumulations were neuronal cells.

CONCLUSIONS

We propose that the free iron deposition in the brain of sudden fetal and infant death victims could be a catabolic product of maternal methemoglobinemia, a biomarker of oxidative stress likely due to nicotine absorption.

Parenteral iron therapy is associated with a characteristic pattern of iron staining on bone marrow aspirate smears

We developed anecdotal evidence that parenteral iron therapy is associated with a characteristic pattern of iron staining in bone marrow aspirate smears. In this pattern, uniform blue granules are observed within reticuloendothelial cells/stromal cells with Prussian blue staining, many times in curvilinear arrays. To test this hypothesis, marrow cases submitted for morphologic evaluation to our laboratory during an approximate 2-month period in 2006 were assessed for this pattern, and, when it was observed, clinical information was sought to determine if the patient had received parenteral iron. Fourteen cases were identified that displayed the pattern of interest. In 10 of these cases, the pattern was widespread (numerous granules present within virtually all marrow spicules), whereas in 4 cases, the pattern was seen only focally. In all cases in which the pattern was widespread, patients were found to have received parenteral iron at some point before the aspiration procedure. Our findings indicate that parenteral iron therapy is associated with a characteristic pattern of iron staining in bone marrow aspirate smears.

Evaluating SPIO-labelled cell MR efficiency by three-dimensional quantitative T2* MRI

An in vitro MR-assay for superparamagnetic iron oxide (SPIO) particle cell labelling assessment via three-dimensional quantitative T(2) (*) MR microscopy was proposed. On high-resolution images, and due to the high susceptibility difference between the particles and the surrounding medium, SPIO internalized in cells induces signal loss which may be counted and measured on T(2) (*) maps. The increase in both labelled cell percentage and the average perturbation volume with an added amount of iron in the incubation medium proved that intracellular iron uptake is dependent upon the initial concentration of incubation iron. It also proved that the observed increases in total cellular iron uptake measured by inductively coupled plasma optical emission spectroscopy are due to both an increase in the iron mass per cell and also an increase in labelled cell concentration. MR results were compared with Prussian blue staining histology. The sensitivity of the MR methodology was then used to distinguish labelling differences for two different types of particle coating. The MRI-assay we proposed is a compulsory tool to optimize labelling efficiency in order to improve in vivo cell detection. Key parameters for detection, such as the percentage of cell labelling, the effect on the image for a given amount of internalized iron and labelling distribution among a cell population, are easily obtained. The comparison of different contrast agents for labelling one cell type, the assessment of one type of contrast agent for labelling different cell types and/or the evaluation of labelling strategies, are possible without having recourse to classical methods, and provide improved accuracy, since the principle is based on intracellular relaxivity.

Erythrocyte plasma membrane redox system in human aging

Eukaryotic cells display a plasma membrane redox system (PMRS) that transfers electrons from intracellular substrates to extracellular electron acceptors. The physiologic importance of PMRS is still not fully understood. The authors have carried out studies to determine the activity of PMRS in human erythrocytes as a function of age and correlate the activity with total plasma antioxidant capacity in an effort to understand the role of PMRS in human aging. The study was carried out on 80 normal healthy subjects of both genders between the ages of 18 and 85 years. The activity of erythrocyte PMRS was estimated by following the reduction of ferricyanide. The total antioxidant capacity of the plasma was estimated in terms of Ferric Reducing Ability of Plasma (FRAP) values. A significant (p < 0.0001) positive correlation (r = 0.7797) is observed between PMRS activity of erythrocytes and human age. There is an age-dependent decrease in total plasma antioxidant capacity measured in terms of FRAP values. A highly significant correlation is observed between PMRS activity and plasma FRAP values. The authors hypothesize that the increased PMRS in erythrocytes during aging may be a protective mechanism of the system for efficient extracellular DHA reduction and ascorbate recycling under condition of increased oxidative stress.

DNA as a support for glucose oxidase immobilization at Prussian blue-modified glassy carbon electrode in biosensor preparation

An amperometric glucose biosensor has been developed using DNA as a matrix of Glucose oxidase (GOx) at Prussian-blue (PB)-modified glassy carbon (GC) electrode. GC electrode was chemically modified by the PB. GOx was immobilized together with DNA at the working area of the PB-modified electrode by placing a drop of the mixture of DNA and GOx. The response of the biosensor for glucose was evaluated amperometrically. Upon immobilization of glucose oxidase with DNA, the biosensor showed rapid response toward the glucose. On the other hand, no significant response was obtained in the absence of DNA. Experimental conditions influencing the biosensor performance were optimized and assessed. This biosensor offered an excellent electrochemical response for glucose concentration in micro mol level with high sensitivity and selectivity and short response time. The levels of the relative standard deviation (RSDs), (<4%) for the entire analyses reflected a highly reproducible sensor performance. Through the use of optimized conditions, a linear relationship between current and glucose concentration was obtained up to 4 x 10(-4) M. In addition, this biosensor showed high reproducibility and stability.

Phenotypic study of human gingival fibroblasts labeled with superparamagnetic anionic nanoparticles

BACKGROUND

A specific labeler of the human gingival fibroblast (HGF) does not exist. Anionic maghemite nanoparticles allow labeling of a wide cell variety and their recognition in cellular, organotypical, and animal models.

METHODS

We studied internalization effects of nanoparticles on an HGF phenotype in vitro, evaluating transcription and secretion of connective tissue remodeling molecules, i.e., matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs), and cytokines controlling their activation/inhibition, i.e., transforming growth factor-beta (TGF-beta1), tumor necrosis factor-alpha (TNF-alpha), and interleukins 1beta and 4 (IL-1beta and IL-4). After proliferation kinetics, cellular uptake was studied by Perls coloration and magnetophoresis on labeled culture. Dot blotting, Western blotting, and zymography were used to detect MMP-1, -2, and -3 and TIMP-1 and -2 secretions in culture supernatants, and reverse transcription-polymerase chain reaction (RT-PCR) was performed to detect the mRNA expression of these molecules. Enzyme-linked immunosorbent assay (ELISA) tests were used to determine TGF-beta1, TNF-alpha, IL-1beta, and IL-4 levels.

RESULTS

Our data indicated high (15.3+/-5.8 pg/cell) but heterogeneous distribution of nanoparticles in HGF. Twenty-four hours after labeling, MMP-1, -2, and -3 and TIMP-2 secretion increased (P<0.001) with RT-PCR confirmation at 12 hours, whereas TIMP-1 did not. IL-1beta increased at day 1 (D1) (P<0.001) and IL-4 at D3 (P<0.01), but not TGF-beta1 or TNF-alpha.

CONCLUSIONS

After labeling with these maghemite nanoparticles, HGF increased secretion of IL-1beta at D1, probably inducing the increase of MMP-1, -2, and -3 and TIMP-2. The increase of IL-4 secretion began with the decreased synthesis of MMPs and TIMPs at D3. Despite this transitory inflammatory reaction at 3 days following internalization, maghemite nanoparticles did not affect HGF phenotype, thereby authorizing their use as labelers.

Gastric Siderosis

Recently, we encountered 2 cases of diffuse iron deposition in gastric antral and fundic glandular epithelium, which in 1 patient eventually led to the diagnosis of hemochromatosis. Gastric mucosal siderosis (GS) has previously been described in hemochromatosis patients, alcoholics, and in association with iron medications. However, the prevalence of various patterns of iron deposition in the gastric mucosa and their clinical significance have not been studied in detail. The 2 index cases mentioned above and 500 additional consecutive gastric biopsies examined over a period of 8 months at our institution were stained for iron by the Prussian blue method. In addition, all patients with genetic hemochromatosis diagnosed by liver biopsy in our department between 1998 and 2003 who also had gastric biopsies were identified from the surgical pathology files and included in the study (n = 3). The location of iron deposition [stromal cells (endothelium, fibroblasts, macrophages), glandular epithelium, or extracellular] was recorded and subjectively graded as 1+ to 3+ according to the severity of deposition within the mucosa. Relevant histologic changes (inflammation, presence of H. pylori, ulceration) and clinical features were reviewed. Three patterns of GS were identified: A) "nonspecific GS" with predominant iron deposition in the stromal cells including macrophages, and focally in epithelium; B) "iron-pill gastritis" with often mild gastritis and reactive gastropathy type changes, and mostly extracellular deposition with focal stromal cells and epithelial deposition; and C) predominant deposition in antral and fundic glandular epithelium. Of the 500 cases studied, a total of 18 (3.6%) cases were found to have GS. Of these 18 cases, 11 (2.2%) showed pattern A, 4 (0.8%) showed pattern B, and 3 (0.6%) showed pattern C. The GS in patterns A and B was always focal or patchy (1+ to 2+), whereas in pattern C it was generally diffuse and strong (2+ to 3+). A history of oral iron medication was present in 2 (n = 11, 0.4%) patients with pattern A, in all patients with pattern B (n = 4, 100%), and in none of patients with pattern C (n=3, 0%). Varying degrees of mucosal inflammation were noted in patients with pattern A cases, and 2 had evidence of active Helicobacter pylori infection. Of the 3 cases with known hemochromatosis, only one gastric biopsy showed pattern C GS (1+). In conclusion, gastric mucosal siderosis is relatively uncommon (3%) but is important to look for as it may lead to a diagnosis of hemochromatosis in some cases. Three patterns are recognized: A) a "nonspecific" stromal cell predominant pattern, which may be associated with gastric inflammation, possibly prior mucosal hemorrhages or iron medications; B) extracellular coarse clumps of crystalline iron deposition associated with oral iron medications, mild gastritis, and reactive gastropathy type changes ("Iron-pill gastritis"); and C) gastric glandular siderosis, which may be associated with systemic iron overload/hemochromatosis.

Transfection of neuroprogenitor cells with iron nanoparticles for magnetic resonance imaging tracking: cell viability, differentiation, and intracellular localization

PURPOSE

Magnetic resonance imaging (MRI) can track labeled cells in the brain. The use of hemagglutinating virus of Japan envelopes (HVJ-Es) to effectively introduce the contrast agent to neural progenitor cells (NPCs) is limited to date despite their high NPC affinity.

PROCEDURES

HVJ-Es and Lipofectamine 2000 were compared as transfection vehicles of superparamagnetic iron oxide (SPIO). Labeled NPCs were examined for iron content, MRI signal change, and fundamental cell characteristics. Prussian Blue staining was used after differentiation to determine SPIO localization.

RESULTS

HVJ-Es transfected up to 12.5 +/- 8.8 times more SPIO into NPCs. HVJ-Es do not affect cell viability or differentiation capability. Superparamagnetic iron oxide was disseminated in both the soma and neurites.

CONCLUSIONS

These findings indicate that HVJ-Es are an effective vehicle for SPIO transfection of NPCs. The intracellular localization after differentiation raises the question as to the capability of MRI to distinguish cell migration from axonal or dendritic growth in vivo.

An amperometric glucose biosensor based on poly(o-aminophenol) and Prussian blue films at platinum electrode

Prussian blue (PB), as a good catalyst for the reduction of hydrogen peroxide, has been combined with nonconducting poly(o-aminophenol) (POAP) film to assemble glucose biosensor. Compared with PB-modified enzymatic biosensor, the biosensor based on glucose oxidase immobilized in POAP film at PB-modified electrode shows much improved stability (78% remains after 30 days) in neutral medium. Additionally, the biosensor, at an applied potential of 0.0 V, exhibits other good characteristics, such as relative low detection limit (0.01 mM), short response time (within 5s), large current density (0.28 mA/cm2), high sensitivity (24 mAM(-1)cm(-2)), and good antiinterferent ability. The apparent activation energy of enzyme-catalyzed reaction and apparent Michaelis-Menten constant are 34.2 KJmol(-1) and 10.5 mM, respectively. In addition, effects of temperature, applied potential used in the determination, pH value of the detection solution, and electroactive interferents on the amperometric response of the sensor were investigated and are discussed.

Neuromelanin associated redox-active iron is increased in the substantia nigra of patients with Parkinson's disease

Degeneration of dopaminergic neurones during Parkinson's disease is most extensive in the subpopulation of melanized-neurones located in the substantia nigra pars compacta. Neuromelanin is a dark pigment produced in the dopaminergic neurones of the human substantia nigra and has the ability to bind a variety of metal ions, especially iron. Post-mortem analyses of the human brain have established that oxidative stress and iron content are enhanced in association with neuronal death. As redox-active iron (free Fe2+ form) and other transition metals have the ability to generate highly reactive hydroxyl radicals by a catalytic process, we investigated the redox activity of neuromelanin (NM)-aggregates in a group of parkinsonian patients, who presented a statistically significant reduction (- 70%) in the number of melanized-neurones and an increased non-heme (Fe3+) iron content as compared with a group of matched-control subjects. The level of redox activity detected in neuromelanin-aggregates was significantly increased (+ 69%) in parkinsonian patients and was highest in patients with the most severe neuronal loss. This change was not observed in tissue in the immediate vicinity of melanized-neurones. A possible consequence of an overloading of neuromelanin with redox-active elements is an increased contribution to oxidative stress and intraneuronal damage in patients with Parkinson's disease.

Predictive value of absent bone marrow iron stores in the clinical diagnosis of iron deficiency anemia

The examination of Prussian-blue-stained bone marrow aspirates for the presence or absence of histiocytic iron granules has been considered the gold standard in evaluating iron-depeleted states. We performed this study to evaluate the predictive accuracy of absent stainable bone marrow iron for iron deficiency anemia (IDA). A retrospective study was performed on an unselected series of 53 consecutive bone marrow biopsy specimens. Only those patients who had totally depleted iron stores and who had iron studies done within 6 months of bone marrow biopsy were included in the study. Based on these criteria, 12 patients were found eligible. After complete evaluation to determine the cause of the patient's illness, the final diagnosis was IDA in only 6 patients (50%). There was no significant difference between the two groups as regards hemoglobin level, reticulocyte count, serum iron levels, total iron binding capacity, red blood cell mean corpuscular volume, ferritin and the transferrin saturation levels. The finding of absent bone marrow iron stores is not necessarily predictive of iron deficiency anemia. The finding of absent stores of iron in the bone marrow needs to be taken in conjunction with other laboratory findings and the clinical scenario while making a diagnosis of IDA, since certain other hematological diseases may co-exist.

Maculas affected by age-related macular degeneration contain increased chelatable iron in the retinal pigment epithelium and Bruch's membrane

OBJECTIVE

To investigate whether iron is involved in the pathogenesis of age-related macular degeneration (AMD).

METHODS

Postmortem AMD-affected (nonexudative or exudative) and healthy maculas were studied using the 3,3'-diaminobenzidine-enhanced Perls Prussian blue stain. The Perls Prussian blue stain was quantified by computer-assisted analysis of digital images. To determine whether the iron was chelatable, sections treated with the iron chelator deferoxamine were compared with adjacent, nonchelated sections.

RESULTS

Compared with healthy maculas, AMD-affected maculas had statistically significant increases in the total iron level. Some of this iron was chelatable. The iron was present in retinal pigment epithelium and Bruch's membrane in maculas from patients who had drusen only, geographic atrophy, and exudative AMD in pathologic areas and, occasionally, in relatively healthy areas.

CONCLUSIONS

Oxidative stress has been implicated in the pathogenesis of AMD by the Age-Related Eye Disease Study. Increased concentrations of iron, which generate highly reactive hydroxyl radicals via the Fenton reaction, may induce oxidative stress in the macula and lead to AMD. As the increased iron concentrations in AMD-affected eyes consist in part of a chelatable iron pool, treatment of patients who have AMD with iron chelators might be considered a potential therapy. While there are, as yet, no clinical data indicating that the treatment of patients who have AMD with iron chelators is beneficial, data presented herein indicate that further investigation of iron concentrations in postmortem tissues and the mechanisms of iron transport in the retina is warranted.

[Demonstration of trivalent iron in decalcified bone marrow specimens. Comparative study of standard Perls stain on sections and the Perls pre-reaction on fragments]

In the literature the usefulness of the Perls reaction for Iron (Fe+++) stores estimation on bone marrow is largely accepted. However, due to decalcification, there is a considerable disagreement about the accuracy of this staining on osteomedullary tissue. In fact loss of Fe+++ has been claimed by some Authors, and denied by others. In order to check this controversial point in this paper Perls reaction, as a methodological variant, was directly anticipated on fragments (pre-Perls). In this way numerous osteomedullary sternal specimens from autopsies (non hematological cases) were observed in comparison with normal Perls reaction on sections (standard-Perls). In standard-Perls series (A) decalcification was achieved by HCl (alone or in combination with EDTA) or by formic acid. On pre-Perls treated fragments decalcification was an intrinsic effect of the hydrochloride component during Prussian Blue formulation. Nine different procedures of fixation were tested respectively for standard-Perls and pre-Perls. Pre-Perls was performed on pre-fixed (B series) as well as post-fixed material (C series). For the microscopical evaluation was applied the classical grading system proposed by Lundin for histology. Maximum grade was only observed in B and C, was the same in both these series and varied from 2 to 4 depending on autopsic case. Results strongly indicate the superiority of pre-Perls versus standard-Perls, with a differential grading ranging from 2 to 4 grades, in seven procedures of B (two procedures were equivalent in A and B) and in all the procedures of C. The comparison between B and C series showed inferiority of B in four procedures. For control (D series) standard-Perls was systematically performed on sections from pre-Perls: no differences between pre-Perls and pre-Perls + standard-Perls were observed indicating a complete permeation of fragments by Perls reagents. In general terms morphology in pre-Perls B was better than in pre-Perls C and substantially identical to standard procedures of A. Other data are analytically reported.

CONCLUSIONS

Pre-Perls staining (with special reference to five procedures of B) seems to be recommendable for decalcified bone marrow biopsies, in conjunction with standard processing, when an high sensitivity in detection of Fe+++ deposits is required or in absence of aspirate. Pathologists could subsequently decide if this methodological variant is suitable or not for an effective alternative choice in their routine according to morphological and immunohistochemical adequacy.

Ultrastructural analysis of a putative magnetoreceptor in the beak of homing pigeons

With the use of different light and electron microscopic methods, we investigated the subcellular organization of afferent trigeminal terminals in the upper beak of the homing pigeon, Columba livia, which are about 5 microm in diameter and contain superparamagnetic magnetite (SPM) crystals. The SPM nanocrystals are assembled in clusters (diameter, approximately 1-2 microm). About 10 to 15 of these clusters occur inside one nerve terminal, arranged along the cell membrane. Each SPM cluster is embedded in a solid fibrous cup, open towards the cell surface, to which the cluster adheres by delicate fiber strands. In addition to the SPM clusters, a second inorganic iron compound has been identified: noncrystalline platelets of iron phosphate (about 500 nm wide and long and maximally 100 nm thick) that occur along a fibrous core of the terminal. The anatomic features suggested that these nerve endings could detect small intensity changes of the geomagnetic field. Such stimuli can induce deformations of the SPM clusters, which could be transduced into primary receptor potentials by mechanosensitive membrane receptor channels. The subepidermal fat cells surrounding the nerve endings prevent the inside from external mechanical stimuli. These structural findings corresponded to conclusions inferred from rock magnetic measurements, theoretical calculations, model experiments, and behavioral data, which also matched previous electrophysiologic recordings from migratory birds.

Hepatic failure with neonatal tissue siderosis of hemochromatotic type in an infant presenting with meconium ileus. Case report and differential diagnosis of the perinatal iron storage disorders

We report on a female preterm infant with hepatic failure and neonatal tissue siderosis of hemochromatotic type diagnosed by using both histochemistry and atomic absorption spectroscopy. The infant presented with meconium ileus, signs of rapidly progressive hepatic failure, and hyperferritinemia (7132 ng/ml). Despite surgery and intensive care the infant died 32 days after birth. Postmortem examination showed a wrinkled liver with extensive collapse of the hepatic architecture and regenerating nodules as well as hepatic and extrahepatic iron accumulation of hemochromatotic type, sparing the reticuloendothelial system. Atomic absorption spectroscopy confirmed an increase in the iron content of various organs: liver, heart, pancreas, oral salivary gland, kidney, and adrenal gland. The increase in the iron content of various organs was determined by comparing the analysis of the propositus with those of 5 gestationally age-related preterm infants who had died in the intensive care unit: 2 died of meconium aspiration syndrome, the other 3 of hyaline membrane disease, bronchopulmonary dysplasia, and immaturity, respectively. We also compared the analysis of 15 fetuses having a a condition predisposing to iron accumulation (trisomy 21, trisomy 18, cytomegalovirus, amnion infection syndrome, Rhesus- and ABO-incompatibility, congenital hemolysis, anti-phospholipid syndrome, congenital heart disease). Delta F508, the most frequent mutation seen in cystic fibrosis patients, was excluded by gene sequencing. Different noxae causing iron accumulation in the neonatal period have led to the statement that neonatal hemochromatosis may collect different etiologies, such as metabolic disorders, infections, chromosomal aberrations, and immunological disorders. In this study, we report the singular evidence of neonatal iron accumulation of hemochromatotic type in an infant presenting with meconium ileus and propose a classification of the neonatal disorders associated with iron accumulation.

The usefulness of serum transferrin receptor and ferritin for assessing anemia in rheumatoid arthritis: comparison with bone marrow iron study

OBJECTIVES

This study was aimed at investigating the usefulness of serum transferrin receptor (sTfR) and ferritin in anemic patients with rheumatoid arthritis (RA) compared with bone marrow storage iron and other tests for anemia.

METHODS

Fifty-five anemic RA patients underwent anemia study. Bone marrow iron stain was performed in 18 patients. sTfR and serum ferritin levels were compared with bone marrow iron stores.

RESULTS

(1) Mean sTfR concentration was 2.63+/-1.91 mg/L, (2) sTfR correlated with most indicators of anemia, (3) sTfR showed no correlation with CRP and ESR, whereas ferritin did, and (4) sTfR was higher in the "iron depleted" subgroup than in the "iron nondepleted" subgroup in bone marrow study.

CONCLUSION

The measurement of sTfR and ferritin is useful in finding the cause of anemia in RA and is a possible substitute for invasive bone marrow iron study.

Application of Prussian blue-based optical sensor in pharmaceutical analysis

Optical flow-through cell-detector with incorporated transparent chemosensitive layer of Prussian blue has been applied in simple, single-channel flow-injection system for pharmaceutical analysis. The reductant analyte converts the Prussian blue based sensing layer to Prussian white form, and the attendant color change is used for sensing. Discoloration of the film is spectrophotometrically detected at 720 nm wavelength. The flow injection system has been successfully used for selective determination of ascorbic acid in simple and complex pharmaceuticals. The method is free from interferences caused by various ions and active ingredients commonly found in pharmaceuticals. The flow-through sensor is useful for spectrophotometric flow-injection analysis of intensively colored and turbid samples. The results of medicine analysis are comparable to those obtained using reference pharmacopeal method. The analytical system could be also used for determination of cysteine and hydrogen peroxide in medicines.

Magnetic resonance imaging of atherosclerotic plaque with ultrasmall superparamagnetic particles of iron oxide in hyperlipidemic rabbits

BACKGROUND

Based on the observation that ultrasmall superparamagnetic particles of iron oxides (USPIOs) are phagocytosed by cells of the mononuclear phagocytic system, the purpose of this study was to evaluate their use as a marker of atherosclerosis-associated inflammatory changes in the vessel wall before luminal narrowing is present.

METHODS AND RESULTS

Experiments were conducted on 6 heritable hyperlipidemic and 3 New Zealand White rabbits. 3D MR angiography (MRA) of the thoracic aorta was performed on all rabbits by use of a conventional paramagnetic contrast agent that failed to reveal any abnormalities. One week later, all rabbits except 1 of the hyperlipidemic animals were injected with a USPIO contrast agent (Sinerem, Guerbet) at a dose of 1 mmol Fe/kg. 3D MRA data sets collected over the subsequent 5 days showed increasing signal in the aortic lumen. Whereas the aortic wall of the control rabbits remained smooth and bright, marked susceptibility effects became evident on day 4 within the aortic walls of hyperlipidemic rabbits. Ex vivo imaging of aortic specimens confirmed the in vivo results. Histopathology documented marked Fe uptake in macrophages embedded in atherosclerotic plaque of the hyperlipidemic rabbits. Electron microscopy showed multiple cytoplasmic Fe particles in macrophages. No such changes were seen in control rabbits or in the hyperlipidemic rabbit that had not received Sinerem.

CONCLUSIONS

USPIOs are phagocytosed by macrophages in atherosclerotic plaques of the aortic wall of hyperlipidemic rabbits in a quantity sufficient to cause susceptibility effects detectable by MRI.

Association between hemosiderin deposition and blood vessel regression during involution of foreign-body granuloma. Histochemical and ultrastructural study

We have characterized the sequence of events resulting in vessel occlusion and stasis of blood flow during involution of a foreign-body granuloma using histochemistry and electron microscopy. In the microvascular bed of the granulation tissue accompanying the progressive resorption of an implanted collagen sponge, endothelial cells protruded into the vascular lumen, resulting in the occlusion of the lumens of venules and capillaries. Examination of sections stained by the TUNEL method showed brown-yellow stained structures in the vascular lumen during regression of blood vessels. However, the ultrastructural profiles of endothelial cells effectively involved in the vessel occlusion showed none of the cardinal morphological features of apoptosis. These endothelial cells which displayed remarkable indentations of their nuclei in the form of nuclear pinches and/or deep pockets bulged conspicuously into the lumen. Such endothelial cells served as effective valves by protruding into the lumens of small blood vessels, and eventually the vessels were completely plugged by red blood cells. However, protruding endothelial cells subsequently shed into the vascular lumen by deviating themselves from the constitution of the vessel wall. The endothelial cells undergoing apoptosis were removed by intraluminal macrophages. Between the 130 and 140 day, the occurrence of small vessels tightly packed with erythrocytes reached a peak value in the granulation tissue and was accompanied by hemosiderin deposits. The plugged vessels were frequently associated with erythrocyte extravasation, leading to openings between degenerated endothelial cells due to the disappearance of endothelial cytoplasmic projections. Extravasated erythrocytes were rapidly eliminated by phagocytic cells such as mononuclear macrophages and multinucleated giant cells, and ended as hemosiderin deposits in granulation and/or scar tissue at the end of the experimental period (130-140 days). The morphological analysis of this regression sequence suggests that the protrusion of endothelial cells with the nuclear deformation is a mechanism contributing to the occlusion of blood vessels and consequently leads to erythrocyte extravasation.

Iron-rich foci in chronic viral hepatitis

Stainable iron in the liver (hemosiderosis) is most commonly seen in individuals with homozygous genetic hemochromatosis, prior transfusion, hemolysis, porphyria cutanea tarda, and chronic alcohol-induced liver disease. In chronic viral hepatitis, however, significant hepatocellular hemosiderosis is uncommon. This report describes unusual foci of hepatocellular hemosiderosis ("iron-rich foci" or IRF) in liver biopsy specimens from three patients with chronic hepatitis with or without cirrhosis (two hepatitis C-related, one hepatitis B-related). IRF present within the lobular parenchyma or cirrhotic nodules contrasted sharply with the immediately adjacent hemosiderin-negative liver tissue. Serum iron indices were abnormal in all three patients, but homozygous hemochromatosis was ruled out based on the hepatic iron concentration and hepatic iron index for each case. These cases highlight the potential for irregular iron storage in chronic viral liver disease and possible confusion with genetic hemochromatosis. The possible pathogenesis of IRF and the relationship of iron storage to the outcome of interferon therapy in chronic viral hepatitis are discussed.

THE COMBINED USE OF MICROINCINERATION AND THE PRUSSIAN BLUE REACTION FOR A MORE SENSITIVE HISTOCHEMICAL DEMONSTRATION OF IRON

The Prussian blue reaction was found useful for the demonstration of iron in the celloidinized ash left after direct microincineration. This method has been suggested previously, although it has not become popular. It is a very sensitive means of demonstrating the presence of iron in tissues and has application in cases in which the quantities of iron are very small or in which the iron is in a protein-bound form that fails to give a positive reaction with the usual Prussian blue technique.

Identification of Fourier transform infrared signals from the non-heme iron in photosystem II

Fourier transfer infrared (FTIR) signals originating from a high-potential electron acceptor in PS II were studied by flash-induced FTIR difference spectroscopy. Redox titration of these signals using ferri-ferrocyanide mixtures showed midpoint potentials (Em) of 489 +/- 12 and 426 +/- 9 mV at pH 5.5 and 6.5, respectively, revealing a pH dependence of about -60 mV/pH unit. These Em values and pH dependence were in good agreement with those of the non-heme iron, so-called Q400, located between QA and QB. This indicates that the observed FTIR signals are due to changes in ligands of the non-heme iron and surrounding protein moieties induced on photoreduction from Fe3+ to Fe2+.

Interaction of iron polymers with blood mononuclear cells and its detection with the Prussian Blue reaction

An inhibitory effect of iron salts on various immune functions in vitro has been reported in several laboratories during the last few years. This study confirms and extends those observations by showing that iron citrate inhibits the mitogen-induced (PHA, Con A and PWM) lymphocyte proliferation. Such inhibition is observed in the presence of ferric citrate with a metal-to-ligand molar ratio of 1:1 but not with ferric citrate with metal-to-ligand molar ratio 1:20 in which the formation of polynuclear iron complexes is prevented. Increasing the concentration of serum in the culture medium diminished the inhibitory effect of 1:1 ferric citrate. Using the Prussian Blue reaction the presence of ferric iron was observed on the cell surface. It is proposed that the deposition of polynuclear iron complexes on the lymphocytes membrane is one of the possible factors determining the iron inhibitory effect.

[Applied anatomy of lymph drainage of lower lip mucosa]

The lymph drainage of lower lip mucosa was studied in 30 fresh cadavers of fetus and neonatus by submucosa injection of 30% Prussian blue of chloroform solution. The collecting lymphatics in lateral third of both the right and left sides of the lower lip mucosa ran laterally to the angles of the mouth, and then back- and downward between mandible and depressor muscle of angle of mouth, and finally, accompanying the facial vessels, emptied into submandibular lymph nodes. The efferent lymphatics of the latter emptied into angular lymph nodes and jugulo-omohyoid lymph nodes. The collecting lymphatics in the middle third of the lower lip mucosa went superficially to the mental muscle and downward into submental lymph nodes. The efferent lymphatic of the latter emptied, anteriorly to the body of the hyoid bone, latter- and downward into right and left jugulo-omohyoid lymph nodes. All collecting lymphatics lie in the loose connective tissue between the muscles.

Methods in pathology. The use of a colloidal silver (AgNOR) method in assessing bone marrow iron stores and sideroblasts

Previous observations indicated that a colloidal silver (AgNOR) method identifies iron-containing bone marrow cells. In this study we examined AgNOR-stained bone marrow smears from 30 selected patients and compared the results with the conventional Prussian blue (PB) method for staining storage iron and sideroblasts, including ringed sideroblasts (RS). Erythroid cells were easily identified, and iron granules stained as distinct, small, round, black dots. In all cases containing sideroblasts and RS, their proportion expressed as the percentage of all normoblasts was higher with AgNOR than with PB. Pronormoblastic and basophilic sideroblasts were detected more often with AgNOR than with PB. Sideroblasts were noted in cases with no PB-stainable iron. Ringed sideroblasts were identified in a number of cases in which they were nondetectable with PB. In cases of myelodysplastic syndrome, pronormoblastic and basophilic RS were found more often than with PB. Hemosiderin deposits within the macrophages were clearly visualized as black aggregates and were seen in cases with no PB-stainable iron. There were no instances where iron or any category of sideroblasts was seen with PB only. In our sampling, the AgNOR method was more sensitive yet specific, and it produced staining results of superior quality.

Histochemical demonstration of iron but not aluminum in a case of dialysis-associated osteomalacia

A patient undergoing hemodialysis is described in whom osteomalacia developed despite protracted treatment with calcitriol. Appropriately stained biopsy sections exhibited iron at all marrow-osteoid interfaces and a small fraction of trabecular mineralization fronts. Aluminum, the metal usually associated with osteomalacia in patients undergoing hemodialysis, was not histochemically demonstrable, even though spectrophotometrically measured bone aluminum content was substantial. These observations suggest two interpretations: iron may have caused osteomalacia through effects on bone cells and at mineralization fronts; alternatively, aluminum may have caused osteomalacia while remaining histochemically undetectable. It is possible that both metals exerted toxic effects simultaneously.

A study on the cytoplasmic granules of the pericardial gland cells of some bivalve molluscs

The pericardial glands of three bivalve molluscs are composed of convoluted epithelium that appears as pouches on the auricles of Mytilus and as tubules in the connective tissue at the anterior-lateral sides of the pericardial cavity of Mercenaria and Anodonta. The pericardial gland cells are attached to each other by many randomly placed desmosome-like cell junctions and gap junctions. Belt-desmosomes that are characteristic of epithelial cells were not observed. The basal membrane of these cells is invaginated producing complex interdigitating cytoplasmic processes and filtration slits. The pericardial gland cells stain for the presence of iron with Prussian blue stain. Electron-dense and electron-lucent granules of various diameters are present in the cytoplasm. Many electron-dense granules contain ferritin-like particles in which the presence of iron has been demonstrated by microanalysis. It is suggested that these particles are the iron storage protein ferritin since they contain iron, and are water soluble, heat stable, and morphologically similar to mammalian ferritin. Ferritin particles are probably both synthesized and broken down by the pericardial gland cells; thus the pericardial gland cells may be involved in iron homeostasis in these molluscs.

Stainable iron in gastric and duodenal mucosa of primary hemochromatosis patients and alcoholics

The presence of iron in gastric and duodenal mucosa was investigated with Perl's stain in endoscopic biopsies from 13 patients with overt primary hemochromatosis, 10 chronic heavy alcohol abusers, and 10 patients with nonulcer dyspepsia. In the primary hemochromatosis patients marked iron deposition was found in cells at the base of glands in the gastric body and antrum in nine cases, and in crypt cells and Brunner gland cells of the duodenum in six. Iron was detected in the lamina propria of the stomach in five and duodenum in four cases. A similar distribution of iron overload, usually of lesser degree, was also observed in five alcoholics. Serum ferritin levels and the degree of gastric and/or duodenal iron deposits did not correlate in either hemochromatosis patients or alcoholics. No gastric or duodenal siderosis was observed in nonulcer dyspepsia cases. The absence of gastric and duodenal stainable iron in some hemochromatosis patients and its presence in some alcoholics suggests that the diagnostic value of upper gastrointestinal biopsy in primary hemochromatosis is limited.

Sequential histochemical staining for resident and recruited macrophages

A new histochemical technique is described that permits differentiation of resident from recruited macrophages by staining of paraffin sections of tissues from rats and mice. Resident macrophages are identified by their ability to phagocytose and retain intravenously injected colloidal Prussian blue. New macrophages that emigrate into tissue are identified by phagocytosis of a second colloid, iron dextran. Paraffin sections of formalin-fixed tissues are sequentially stained for the presence of the two colloids with different chromogens, the endogenous pseudo-peroxidase activity of colloidal Prussian blue used to catalyze the polymerization of diaminobenzidine and after conversion of iron dextran to Prussian blue, the second colloid used to catalyze the polymerization of tetramethylbenzidine. The staining results in resident macrophages staining brown while newly recruited macrophages stain blue. The studies have shown that colloidal Prussian blue is stable in vivo and neither loses its catalytic activity nor undergoes extensive redistribution. They also show that the technique can be used to measure Kupffer cell recruitment stimulated by complete Freund's adjuvant in rats and tumor-associated macrophage recruitment in subcutaneous and spontaneous liver metastases in mice.

Total phospholipid analysis in human milk without acid digestion

A colorimetric method for measuring the organic phosphorus in human milk without acid digestion was studied. Human milk samples were assayed and compared to phosphatidylcholine, phosphatidylethanolamine, and sphingomyelin standards. Spectral and calibration curves prepared from phospholipid standards were equivalent. Absorption maxima occurred between 720 and 740 nm. A reproducibility study of twenty total lipid samples had a coefficient of variation of 3.8%. Phosphorus ranged from 4.7 to 5.5 micrograms with a mean +/- SD of 5.2 +/- 0.2 micrograms P. The recovery of phosphatidylcholines added to 10 mg samples of human milk triacylglycerols ranged from 99.0 to 102.1%. The results from the new method were comparable to those obtained by a modified Fiske and Subbarow method for measuring inorganic phosphorus after sulfuric acid digestion of the milk lipids. We concluded that the new method provides a satisfactory alternative for the determination of organic phosphorus in human milk.

Iron deposition in the integument of lampreys

The integument of larval, parasitic adult, and upstream-migrant lampreys (Petromyzon marinus) was examined for iron deposition using light microscopic histochemistry and routine and histochemical procedures in the electron microscope. Ferritin particles, representing ferric iron, are present throughout most of the cytoplasmic matrix and within dense granules and vacuoles of epidermal mucous cells, but are not located in skein or granular cells. These particles are abundant in mucous cells of the dorsal surface but not the ventral surface and are more concentrated in adult lampreys compared to larva. Histochemistry revealed only sparse amounts of ferrous iron. Iron is not present in the dermis but is found in adipocytes of a subcutaneous layer. The deposition of integumentary iron is discussed with reference to body pigmentation and excretion of this metal.

Iron deposits surrounding multiple sclerosis plaques

Autopsy samples from cerebral areas of five brains from patients with multiple sclerosis (MS) and from six control brains were stained with Perls acid ferrocyanide to detect nonheme iron present as hemosiderin. Positive iron reactions were observed only in MS sections surrounding demyelinated plaques. Myelinated white matter near the lesion contained numerous iron-laden ovoid bodied and axons that stained positively for iron. Positive reactions were also found within blood vessels of gray matter near the lesion. A possible source of the iron was extravasated blood.

Visualization of Histoplasma capsulatum in bone marrow with Prussian blue iron stain

Bone marrow specimens from patients with disseminated histoplasmosis revealed yeast cells that stained positively with Prussian blue.

The functional basis for nephrographic patterns in acute tubular necrosis

There is considerable evidence that the principal functional abnormality in patients with acute reversible renal failure (ARF, or "acute tubular necrosis") is reduced cortical perfusion with diminished glomerular filtration. However, in such patients, high-dose intravenous urograms most commonly show an immediate obvious nephrogram. Since nephrographic density is believed to depend on the filtration of contrast medium into the tubular lumen, it is difficult to reconcile the early development of the nephrogram if glomerular filtration is reduced. Extensive experiments with both mercuric chloride and glycerol rat models of ARF have confirmed rapid intraluminal accumulation of contrast medium, albeit in reduced amounts. Studies using the normally filtered compound sodium nitroprusside and its precipitation as "prussian blue" suggest rapid transtubular diffusion from peritubular capillaries in kidneys with ARF. This, it is suggested, is also the mechanism for the rapid intraluminal ingress of contrast media and explains the early appearance of nephrogram. The less common intravenous urogram finding in ARF of a slowly developing and increasingly dense nephrogram may then represent cases with only slight tubular necrosis with predominant reduction in glomerular filtration.

["Diaminobenzidine black" as a new histochemical demonstration of exogenous iron (author's transl)]

A new reaction for the histochemical demonstration of exogenous iron, used as a tracer for the study of connectivity in the central nervous system, is described. It consists of, first, the conversion of iron into Prussian blue, which acts secondarily as a catalyst for the oxidation of diaminobenzidine by hydrogen peroxide. The oxidized diaminobenzidine precipitates by polymerization and gives rise to a brown-colored insoluble reaction product. This reaction has a strikingly better sensitivity and contrast than the classical Perls's reaction.

The distribution of glutathione in the rat liver lobule

A quantitative cytochemical method was developed for measuring the GSH (reduced glutathione) content of hepatocytes in different regions of the rat liver lobule. Use of this method enabled us to show that GSH is not evenly distributed within the rat liver lobule. The hepatocytes located within 100 micrometer of the central vein contain much less GSH than do those in other regions of the rat liver lobule. We suggest that this partially explains the peculiar susceptibility of these cells to electrophilic attack by toxic metabolites formed via the microsomal cytochrome P-450 system.

Ferrocyanide staining of transferrin and ferritin-conjugated antibody to transferrin

To evaluate the ultrastructural distribution of transferrin on the surface of L1210 ascites tumor cells, we used ferrocyanide to stain ferric iron (Prussian blue reaction) in transferrin, as well as in ferritin conjugated to antibody that was immunologically attached to the transferrin. Small deposits averaging 5 nm in diameter identified transferrin iron, whereas large cuboidal deposits averaging 50 nm in diameter stained ferritin conjugated-antibody that was bound to both transferrin and apotransferrin on the cell surface. The ability of transferrin to deliver iron to ascites tumor cells was confirmed by kinetic studies of transferrin labeled with 59Fe and 125I. These preliminary results are consistent with release of transferrin iron at the cell surface and demonstrate additional uses for ferrocyanide in ultrastructural cytochemical techniques.

Ultrastructural cytochemistry of iron absorption

Conventional ultrastructural autoradiographic and morphologic studies of the duodenal mucosal cell have generally corroborated physiologic observations of iron absorption, but such methods have limited resolution and fail to distinguish ferric and ferrous iron. This study describes the application of the Prussian blue reaction as an electron microscopic cytochemical stain to the investigation of inorganic iron absorption in iron-deficient, normal, and iron-loaded rats. Ferrous iron is converted to ferric iron at the microvillus membrane. Subsequently intraepithelial ferric iron appears bound to a non-heme acceptor substance in microvilli and later appears as small non-membrane-bound stain deposits which are concentrated in the apical cytoplasm. The appearance of larger stain deposits in the lateral intercellular spaces, in the basal extracellular spaces, and along the intraluminal and extraluminal outer plasmalemma of adjacent endothelial cells of the lamina propria suggests passage of iron from epithelial cells through the lamina propria to blood vessels. The extreme sensitivity of the method compared with simultaneous ultrastructural autoradiographic techniques is demonstrated and suggests usefulness of the method in further studies of iron metabolism.

[Ultrastructural localization of 3-beta-hydroxysteroid dehydrogenase activity in the glandular tissue cells of the testis of Pleurodeles waltlii Michach. (Amphibia, Urodela)]

With the potassium ferricyanide method, the localization of the sites of 3 beta-hydroxysteroid dehydrogenase activity has been investigated in the glandular tissue cells, previously fixed, of the Pleurodeles testis. An abundant copper ferrocyanide precipitate, the final reaction product, is observed in the vicinity of the external faces of the membranes of the smooth endoplasmic reticulum, or in contact with them. A very weak reaction occurs in mitochondrial cristae.

Ultrastructural localization of nonheme celluar iron with ferrocyanide

The Prussian blue reaction was evaluated at the ultrastructural level as a cytochemical method to identify ferric and ferrous iron in rat bone marrow and splenic macrophages. Satisfactory tissue preservation and staining were achieved after fixation for 1 hr in 3% glutaraldehyde and exposure for 30 min to Perls's ferrocyanide solution before routine osmication and embedding. The acid ferrocyanide solution formed cuboidal and irregular electron-opaque deposits which localized ferric iron in the macrophage siderosomes and hyaloplasm. When thin sections were directly stained with the acid ferrocyanide, the stain deposits were much less distinct. The size and number of cytes exhibited sparse evenly distributed stain deposits. Several cells displayed abundant precipitates on the inner surface of the plasmalemma. Prussian blue precipitates were occasionally seen in mitochondria and nuclear euchromatin. Although osmium tetroxide post-fixation improved tissue preservation, it did not enhance the density of the ferri-ferrocyanide precipitate. The ferrocyanide solution yielded cuboidal deposits also in clots impregnated with ferritin, and electron diffraction analysis confirmed the symmetrical crystal structure of these stain precipitates. Smaller irregular precipitates were formed in clots impregnated with FeCl3, or Fe2 (SO4)3 solutions, despite the equally interpreted as indicating that the iron hydroxide core or protein structure of ferritin and hemosiderin contributed to the formation of the ultrastructurally evident cuboidal precipitates, but were not necessary for the formation of a colored reaction product. The acid ferrocyanide solution failed to stain clots formed in FeCI2, CuCI2 or CuCI solutions. Staining with a ferricyanide solution identified only sparse foci of ferrous iron in some siderosomes. This study demonstrates that the Prussian blue reaction can be used ultrastructurally to localize iron cations bound to some nonheme iron binding proteins.