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PubMed2005

Multilayer membranes via layer-by-layer deposition of organic polymer protected Prussian blue nanoparticles and glucose oxidase for glucose biosensing.

Polyelectrolyte multilayers (PEMs) are now widely used for bioanalytical applications. In this work, a bilayer of poly(diallydimethylammonium chloride) (PDDA) and poly(sodium 4-styrenesulfonate) (PSS) is consecutively adsorbed on 3-mercapto-1-propanesulfonic acid modified Au electrode surfaces, forming stable, ultrathin multilayer films. Subsequently, Prussian blue nanoparticles protected by PDDA (denoted as P-PB) and negatively charged glucose oxidase (GOx) are consecutively adsorbed onto the PSS-terminated bilayer. The growth of each of the P-PB/GOx bilayers is followed quantitatively using UV-visible absorption spectroscopy and the electrochemical method. The P-PB nanoparticles can catalyze the electroreduction of hydrogen peroxide formed from enzymatic reaction at lower potential and inhibit the responses of interferents, such as ascorbic acid (AA) and uric acid (UA). Performance of the multilayer films can be tailored by controlling the number of bilayers. Under optimal conditions, a linear range of 0.10 to 11.0 mM and a detection limit of 10 microM were achieved. The glucose biosensor has good stability and reproducibility.

Biosensing Techniques↗
PubMed1996

Photoinduced Magnetization of a Cobalt-Iron Cyanide

Photoinduced magnetization was observed in a Prussian blue analog, K0.2Co1.4- [Fe(CN)6]·6.9H2O. An increase in the critical temperature from 16 to 19 kelvin was observed as a result of red light illumination. Moreover, the magnetization in the ferrimagnetic region below 16 kelvin was substantially increased after illumination and could be restored almost to its original level by thermal treatment. These effects are thought to be caused by an internal photochemical redox reaction. Furthermore, blue light illumination could be used to partly remove the enhancement of the magnetization. Such control over magnetic properties by optical stimuli may have application in magneto-optical devices.

Journal Article↗
PubMed2003

Hemochromatosis secondary to repeated blood transfusions in a dog.

Hemochromatosis was presumptively diagnosed using cytologic examination of liver tissue from an aged male Miniature Schnauzer. The dog was presented after receiving whole blood transfusion every 6-8 weeks for 3 years to treat pure red cell aplasia. The cytologic specimen contained clusters of hepatocytes with abundant intracytoplasmic gold-yellow pigment granules and clumps of extracellular, green-black, globular pigment, both interpreted to be hemosiderin. Histologic sections of liver revealed hepatocellular degeneration with bridging portal fibrosis, lobular atrophy, biliary hyperplasia, and diffuse, severe hemosiderin accumulation. Serum iron and ferritin levels, and dry-weight iron concentrations of liver, heart, and kidneys were markedly increased. Hemosiderin accumulation was confirmed in hepatocytes of cytologic and histologic specimens using Perl's Prussian blue staining. This report is the first description of transfusional hemochromatosis in a dog and is the first to describe its cytologic appearance in a veterinary patient.

Animals↗
PubMed2005

Difference and similarity between non-alcoholic steatohepatitis and alcoholic liver disease.

BACKGROUND: Non-alcoholic steatohepatitis (NASH) and alcoholic liver disease (ALD) are extremely similar in the pathologic findings and pathogenesis. This study aimed to elucidate the difference and similarity between these diseases. METHODS: Twenty-six patients with NASH and 26 with ALD including 11 with alcoholic hepatitis underwent clinico-pathologic analysis. The visceral fat area and liver/spleen ratio, an index of the hepatic fat content, were evaluated with computed tomography. The hepatic iron deposit and oxidative stress induced-lipid peroxidation were estimated by Prussian blue staining and 3-nitrotyrosine staining, respectively. RESULTS: The most prominent difference between NASH and ALD was the nutritional status, although elevation of AST/ALT ratio and gamma-GT is relatively characteristic of ALD. NASH was more frequently associated with diabetes mellitus as compared with ALD. The BMI and serum levels of total cholesterol and cholinesterase were higher in NASH than in ALD. Although the degree and distribution of fibrosis and necro-inflammatory reaction were similar in NASH and ALD, steatosis was more severe in NASH than in ALD. The liver/spleen ratio was lower and the visceral fat area was larger in NASH than in ALD, regardless of the coincidence of alcoholic hepatitis. Interestingly, the visceral fat area positively correlated with ALT and HOMA-IR in NASH, whereas these correlations were not observed in ALD. The hepatic iron deposit was less in NASH than in ALD, whereas lipid peroxidation in NASH was similar to that in ALD with alcoholic hepatitis and more advanced as compared with that in ALD without alcoholic hepatitis. CONCLUSIONS: NASH was characterized with over-nutrition and visceral fat type obesity as compared with ALD. The visceral fat accumulation was associated with hepatic inflammation and insulin resistance in NASH, but not in ALD. The difference in the nutritional status between NASH and ALD is not only reflected in the clinical features but also may closely associate with the mechanisms of hepatocellular damage in these diseases.

Abdomen↗
PubMed2006

Kinetic aspects of ion exchange in KhFek[Fe(CN)6]l*mH2O compounds: a combined electrical and mass transfer functions approach.

The present paper quantifies and develops the kinetic aspects involved in the mechanism of interplay between electron and ions presented elsewhere(1) for K(h)Fe(k)[Fe(CN)(6)](l)*mH(2)O (Prussian Blue) host materials. Accordingly, there are three different electrochemical processes involved in the PB host materials: H(3)O(+), K(+), and H(+) insertion/extraction mechanisms which here were fully kinetically studied by means of the use of combined electronic and mass transfer functions as a tool to separate all the processes. The use of combined electronic and mass transfer functions was very important to validate and confirm the proposed mechanism. This mechanism allows the electrochemical and chemical processes involved in the K(h)Fe(k)[Fe(CN)(6)](l)*mH(2)O host and Prussian Blue derivatives to be understood. In addition, a formalism was also developed to consider superficial oxygen reduction. From the analysis of the kinetic processes involved in the model, it was possible to demonstrate that the processes associated with K(+) and H(+) exchanges are reversible whereas the H(3)O(+) insertion process was shown not to present a reversible pattern. This irreversible pattern is very peculiar and was shown to be related to the catalytic proton reduction reaction. Furthermore, from the model, it was possible to calculate the number density of available sites for each intercalation/deintercalation processes and infer that they are very similar for K(+) and H(+). Hence, the high prominence of the K(+) exchange observed in the voltammetric responses has a kinetic origin and is not related to the amount of sites available for intercalation/deintercalation of the ions.

Journal Article↗
PubMed2005

New drugs 05, part I.

In this article, you'll learn about nine new drugs, including: Prussian blue, which could protect people from radiation exposure following an act of biochemical terrorism. Bevacizumab, a new monoclonal antibody and the first angiogenesis inhibitor for colorectal cancer. Cinacalcet HCl, the first calcimimetic drug for treating hyperparathyroidism. Unless otherwise specified, the information in the following summaries applies to adults, not children. Consult the package insert for information about each drug's safety during pregnancy and breast-feeding. Also consult the package insert, a pharmacist, or a comprehensive drug reference for more details on precautions, drug interactions, and adverse reactions for all these drugs.

Antibodies, Monoclonal↗
PubMed1991

Lower respiratory tract iron burden is increased in association with cigarette smoking.

Iron, by catalyzing the generation of the hydroxyl radical via the Haber-Weiss reaction, may participate in oxidant tissue injury. To determine whether iron might contribute to cigarette smoke-induced lung injury, we estimated the iron content of the lower respiratory tract by measuring intracellular iron content of pulmonary macrophages and extracellular iron content of bronchoalveolar lavage fluid from cigarette smokers and nonsmokers. Bronchoalveolar lavage was performed by using methods that allow for recovery of samples enriched for bronchial and alveolar contents. The intracellular iron content of the alveolar macrophages was determined by staining cytocentrifuged, air-dried pulmonary macrophages with a modified Prussian blue stain and assigning a score of 0 to 3 (0 = no stain, 3 = dense staining throughout the cytoplasm) to 100 macrophages. The extracellular iron level of bronchoalveolar lavage fluid was determined by using modifications of the Ferrozine method of Carter. Macrophage intracellular iron content was measured in a group of cigarette smokers with chronic bronchitis (n = 17), in smokers without chronic bronchitis (n = 15), and in normal volunteers (n = 15). Extracellular iron concentration was determined in a subset of the subjects with chronic bronchitis (n = 12) and in a separate group of normal volunteers (n = 5). The intracellular iron score was elevated in the bronchial sample lavage fluid in both the smokers with chronic bronchitis (45.3 +/- 13.9) and the asymptomatic smokers (26.6 +/- 8.0) compared with the normal individuals (8.1 +/- 1.7, p less than 0.03, both comparisons), but did not differ between the two groups of cigarette-smoking subjects (p = 0.68).(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchitis↗
PubMed2001

Photodeposition of Prussian Blue Films on TiO(2): Additive Effect of Methanol and Influence of the TiO(2) Crystal Form.

The coupling of TiO(2) and transition metal complexes is attempted with the aim of higher functionalization of the TiO(2) photocatalyst. UV irradiation (lambda(ex)>300 nm) of a TiO(2) suspension containing equimolar aqueous solutions of FeCl(3) and K(3)[Fe(CN)(6)] forms uniform thin films of "water-insoluble Prussian blue" (PB, Fe(4)(3+) [Fe(II)(CN)(6)](3)) on the surface of TiO(2) particles. The PB photodeposition is enhanced significantly by the addition of a small amount of CH(3)OH in both the rutile and anatase TiO(2) systems. The activity of anatase TiO(2) is greater than that of rutile in the presence of CH(3)OH (2.46 M) by a factor of 1.6+/-0.2, whereas the activities are comparable in the absence of CH(3)OH. These results are discussed on the basis of a proposed reaction mechanism. Copyright 2001 Academic Press.

Journal Article↗
PubMed2002

Cyanide-limited complexation of molybdenum(III): synthesis of octahedral [Mo(CN)(6)](3-) and cyano-bridged [Mo(2)(CN)(11)](5-).

Octahedral coordination of molybdenum(III) is achieved by limiting the amount of cyanide available upon complex formation. Reaction of Mo(CF(3)SO(3))(3) with LiCN in DMF affords Li(3)[Mo(CN)(6)] x 6DMF (1), featuring the previously unknown octahedral complex [Mo(CN)(6)](3-). The complex exhibits a room-temperature moment of mu(eff) = 3.80 mu(B), and assignment of its absorption bands leads to the ligand field parameters Delta(o) = 24800 cm(-1) and B = 247 cm(-1). Further restricting the available cyanide in a reaction between Mo(CF(3)SO(3))(3) and (Et(4)N)CN in DMF, followed by recrystallization from DMF/MeOH, yields (Et(4)N)(5)[Mo(2)(CN)(11)] x 2DMF x 2MeOH (2). The dinuclear [Mo(2)(CN)(11)](5-) complex featured therein contains two octahedrally coordinated Mo(III) centers spanned by a bridging cyanide ligand. A fit to the magnetic susceptibility data for 2, gives J = -113 cm(-1) and g = 2.33, representing the strongest antiferromagnetic coupling yet observed through a cyanide bridge. Efforts to incorporate these new complexes in magnetic Prussian blue-type solids are ongoing.

Journal Article↗
PubMed1986

Changes in proton relaxation times of the rat spleen during adjuvant-induced immunologic reaction.

Possible changes in magnetic resonance (MR) relaxation times resulting from an immune reaction were evaluated in the rat spleen by means of in vitro proton spectroscopy and an established model of immune disease. Heat-killed Mycobacterium butyricum in Freund's adjuvant was injected intradermally into the tail of 28 rats. Ten normal rats served as controls. At different times following the injection of adjuvant (day 7, day 10, day 12, day 14, or day 22), the spleens were removed and weighed, and proton T1 and T2 relaxation times were measured with a 0.25-T spectrometer (10.7 MHz). Water content was also determined. Specimens of each spleen were histologically examined; this included Prussian-blue staining for detection of hemosiderin. In 22 of the 28 adjuvant-injected rats, spleen T1 values increased significantly, from a mean value of 451 msec +/- 23 S.D. (control rats) to a maximum mean value of 571 +/- 15 S.D., which occurred on day 12; this T1 increase paralleled an increase in weight and water content and a histologic appearance of granulomatous inflammation. In these rats, T2 changes were not significant. In the other six adjuvant-injected rats, spleen T2 relaxation time significantly decreased from a mean value of 42 msec +/- 5 S.D. to a mean value of 32 msec +/- 1 S.D. Histologic evaluation indicated that the origin of this T2 decrease was probably the presence of hemosiderin in the spleens of only these six rats. Mean T1 of these spleens decreased slightly, but not significantly.

Adjuvants, Immunologic↗
PubMed2006

Thermal-induced changes in molecular magnets based on prussian blue analogues.

The thermal-induced changes in molecular magnets based on Prussian blue analogues, M(3)[Fe(CN)(6)](2).xH(2)O (M = Mn, Co, Ni, Cu, Zn, and Cd), were studied from infrared, X-ray diffraction, thermo-gravimetric, Mössbauer, and magnetic data. Upon being heated, these materials loose the crystalline water that enhances the interaction between the metal centers, as has been detected from Mössbauer spectroscopy data. At higher temperatures, a progressive decomposition process takes place, liberating CN(-) groups, which reduces the iron atom from Fe(III) to Fe(II) to form hexacyanoferrates(II). The exception corresponds to the cobalt compound that undergoes an inner charge transfer to form Co(III) hexacyanoferrate(II). In the case of zinc ferricyanide, the thermal decomposition is preceded by a structural transformation, from cubic to hexagonal. For M = Co, Ni, Cu, and Zn the intermediate reaction product corresponds to a solid solution of M(II) ferricyanide and ferrocyanide. For M = Mn and Cd the formation of a solid solution on heating was not detected. The crystal frameworks of the initial M(II) ferricyanide and of the formed M(II) ferrocyanide are quite different. In annealed Mn(II) ferricyanide samples, an increasing anti-ferromagnetic contribution on heating, which dominates on the initial ferrimagnetic order, was observed. Such a contribution was attributed to neighboring Mn(II) ions linked by aquo bridges. In the anhydrous annealed sample such interaction disappears. This effect was also studied in pure Mn(II) ferrocyanide. The occurrence of linkage isomerism and also the formation of Ni(III), Cu(III), and Zn(III) hexacyanoferrates(II) were discarded from the obtained experimental evidence.

Journal Article↗
PubMed2005

Glucose biosensor based on glucose oxidase immobilized in sol-gel chitosan/silica hybrid composite film on Prussian blue modified glass carbon electrode.

An improved amperometric glucose biosensor based on glucose oxidase immobilized in sol-gel chitosan/silica hybrid composite film, which was prepared from chitosan (CS) and methyltrimethoxysilane (MTOS), on the surface of Prussian blue (PB)-modified glass carbon electrode was developed. The film was characterized by FT-IR. Effects of some experimental variables such as ratio of CS to silica, buffer pH, temperature, and applied potential on the current response of the biosensor were investigated. The biosensor fabricated under optimal conditions had a linear response to glucose over the range 5.0 x 10(-5) to 2.6 x 10(-2) M with a correlation coefficient of 0.9948 and a detection limit of 8.0 x 10(-6) M based on S/N = 3. The biosensor had a fast response time of less than 10 s, a high sensitivity of 420 nA mM(-1), a long-term stability of over 60 days, and a good selectivity. The apparent Michaelis-Menten constant K(m) was found to be 3.2 x 10(-3) M. The activation energy for enzymatic reaction was calculated to be 21.9 kJ mol(-1). This method has been used to determine the glucose concentration in real human blood samples.

Biosensing Techniques↗
PubMed2006

Targeted magnetic resonance imaging of Scavidin-receptor in human umbilical vein endothelial cells in vitro.

Current therapeutic approaches to treat cancer are often hampered by the lack of specificity of the drugs used for therapy. Scavidin, a novel fusion protein expressed on cell membranes, could be utilized for targeting of therapeutic molecules. Scavidin exploits the high binding affinity between avidin and biotin and is capable of mediating endocytosis of a bound ligand. In the current study we evaluated the efficiency of biotinylated ultrasmall superparamagnetic iron oxide (USPIO) particles in Scavidin-expressing human umbilical vein endothelial cell (HUVEC) cultures in vitro as a novel receptor-targeted magnetic resonance imaging contrast agent. Biotinylated USPIO (bUSPIO) were targeted to Scavidin adenovirus-transduced HUVECs in vitro. Scavidin expressing cells were capable of binding and mediating endocytosis of the bUSPIO in vitro, which led to a significant decrease in T2 relaxation times, and a loss of signal intensity in comparison to controls. The findings were confirmed with Prussian blue staining for iron and detection of Scavidin by bound biotinylated horseradish peroxidase. Our data shows that biotinylated ligands target specifically to Scavidin-expressing HUVEC in vitro. The utilization of Scavidin gene transfer ex vivo thus constitutes a platform for potential ligand delivery via cell therapy and time-independent imaging of biologic processes.

Adenoviridae↗
PubMed2006

Electrochromic hysteresis performance of a prussian blue film arising from electron-transfer control by a tris(2,2'-bipyridine)ruthenium(II)-doped WO(3) film as studied by a spectrocyclic voltammetry technique.

A [Ru(bpy)(3)](2+) (bpy=2,2'-bipyridine)-doped WO(3) film was prepared as a base layer on a substrate by cathodic electrodeposition from a colloidal triad solution containing peroxotungstic acid (PTA), [Ru(bpy)(3)](2+), and poly(sodium 4-styrenesulfonate) (PSS). A Prussian blue (PB; Fe(II)-Fe(III)) film was cathodically electrodeposited on the [Ru(bpy)(3)](2+)-doped WO(3) film or neat WO(3) film from an aqueous Berlin brown (BB; Fe(III)-Fe(III)) colloid solution to yield a [Ru(bpy)(3)](2+)-doped WO(3)/PB bilayer film or WO(3)/PB bilayer film. For the spectrocyclic voltammogram (SCV) of the WO(3)/PB film, a redox response of Prussian white (PW; Fe(II)-Fe(II))/PB was observed at 0.11 V, however, further oxidation of PB to BB was not allowed by the interfacial n-type Schottky barrier between the WO(3) and PB layers. For the [Ru(bpy)(3)](2+)-doped WO(3)/PB film, any electrochemical response assigned to the redox of PB was not observed in the cyclic voltammogram, however, the in situ absorption spectral change recorded simultaneously showed the significant redox reactions based on PB. The SCV revealed that PW on the [Ru(bpy)(3)](2+)-doped WO(3) film is completely oxidized to PB by a geared reaction of Ru(II)/Ru(III) at 1.05 V, and that 32 % of PB formed is further oxidized to BB by the same geared reaction in the potential scan to 1.5 V. PB was completely re-reduced to PW by a geared reaction of H(x)WO(3)/WO(3) at -0.5 V in the reductive potential scan. These geared electrochemical reactions produced an electrochromic hysteresis performance of the PB film layered on the [Ru(bpy)(3)](2+)-doped WO(3) film.

Journal Article↗
PubMed2005

An amperometric cholesterol biosensor based on multiwalled carbon nanotubes and organically modified sol-gel/chitosan hybrid composite film.

A new type of amperometric cholesterol biosensor based on sol-gel chitosan/silica and multiwalled carbon nanotubes (MWCNTs) organic-inorganic hybrid composite material was developed. The hybrid composite film was used to immobilize cholesterol oxidase on the surface of Prussian blue-modified glass carbon electrode. Effects of some experimental variables such as enzyme loading, concentration of Triton X-100, pH, temperature, and applied potential on the current response of the biosensor were investigated. Analytical characteristics and dynamic parameters of the biosensors with and without MWCNTs in the hybrid film were compared, and the results show that analytical performance of the biosensor can be improved greatly after introduction of the MWCNTs. Response time, sensitivity, linear range, limit of detection (S/N=3), and apparent Michaelis-Menten constant Km are 25s, 0.54 microA mM(-1), 8.0 x 10(-6) to 4.5 x 10(-4) M, 4.0 x 10(-6) M, and 0.41 mM for the biosensor without MWCNTs and 13 s, 1.55 microA mM(-1), 4.0 x 10(-6) to 7.0 x 10(-4) M, 1.0 x 10(-6) M, and 0.24 mM for the biosensor with MWCNTs, respectively. The activation energy of the enzyme-catalyzed reaction was measured to be 42.6 kJ mol(-1). This method has been used to determine the free cholesterol concentration in real human blood samples.

Biosensing Techniques↗
PubMed2005

Rate of iron transfer through the horse spleen ferritin shell determined by the rate of formation of Prussian Blue and Fe-desferrioxamine within the ferritin cavity.

Iron (2+ and 3+) is believed to transfer through the three-fold channels in the ferritin shell during iron deposition and release in animal ferritins. However, the rate of iron transit in and out through these channels has not been reported. The recent synthesis of [Fe(CN)6]3-, Prussian Blue (PB) and desferrioxamine (DES) all trapped within the horse spleen ferritin (HoSF) interior makes these measurements feasible. We report the rate of Fe2+ penetrating into the ferritin interior by adding external Fe2+ to [Fe(CN)6]3- encapsulated in the HoSF interior and measuring the rate of formation of the resulting encapsulated PB. The rate at which Fe2+ reacts with [Fe(CN)6]3- in the HoSF interior is much slower than the formation of free PB in solution and is proceeded by a lag period. We assume this lag period and the difference in rate represent the transfer of Fe2+ through the HoSF protein shell. The calculated diffusion coefficient, D approximately 5.8x10(-20) m2/s corresponds to the measured lag time of 10-20 s before PB forms within the HoSF interior. The activation energy for Fe2+ transfer from the outside solution through the protein shell was determined to be 52.9 kJ/mol by conducting the reactions at 10 approximately 40 degrees C. The reaction of Fe3+ with encapsulated [Fe(CN)6]4- also readily forms PB in the HoSF interior, but the rate is faster than the corresponding Fe2+ reaction. The rate for Fe3+ transfer through the ferritin shell was confirmed by measuring the rate of the formation of Fe-DES inside HoSF and an activation energy of 58.4 kJ/mol was determined. An attempt was made to determine the rate of iron (2+ and 3+) transit out from the ferritin interior by adding excess bipyridine or DES to PB trapped within the HoSF interior. However, the reactions are slow and occur at almost identical rates for free and HoSF-encapsulated PB, indicating that the transfer of iron from the interior through the protein shell is faster than the rate-limiting step of PB dissociation. The method described in this work presents a novel way of determining the rate of transfer of iron and possibly other small molecules through the ferritin shell.

Animals↗
PubMed2004

Heme-oxygenase-mediated iron accumulation in the liver.

Heme oxygenase (HO) isozymes, HO-1 and HO-2, catalyze the conversion of heme to iron, carbon monoxide, and biliverdin. The present study was aimed at elucidating the role of the HO system in iron accumulation and oxidative stress in the liver. We have also studied the regulation of an iron exporter, ferroportin-1 (FPN-1), as an adaptive response mechanism to increased iron levels. Sprague-Dawley rats were treated with HO inducer hemin or HO inhibitor tin-protoporphyrin IX (SnPPIX) for 1 month. A portion of liver tissues was subjected to RT-PCR for HO-1, HO-2, and FPN-1 gene expression as well as an HO activity assay. Paraffin-embedded tissues were stained for iron with Prussian blue. Hepatic iron concentration was measured by High Resolution-Inductively Coupled Plasma-Mass Spectrometry. 8-hydroxy-2'-deoxyguanosine (8-OHdG) stain, a sensitive and specific marker of oxidative DNA damage, was performed to assess oxidative stress. Hemin treatment led to augmented HO expression and activity in association with increased iron accumulation and oxidative stress. FPN-1 expression was also found to be upregulated. SnPPIX treatment reduced HO activity, intracellular iron levels, and oxidative stress as compared to controls. Our data provides evidence of increased HO activity as an important pro-oxidant mechanism leading to iron accumulation in the liver.

Animals↗
PubMedDate not supplied

DMT1 genetic variability is not responsible for phenotype variability in hereditary hemochromatosis.

BACKGROUND/AIMS: Homozygosity for a cysteine to tyrosine translocation at position 282 within the HFE gene (C282Y) is responsible for over 90% of hereditary hemochromatosis (HH) in Celtic populations. Determining those C282Y homozygotes at greatest risk for iron overload is a major clinical concern as only a small percentage will develop clinically significant iron overload. Divalent metal transport protein (DMT1) on the apical surface of duodenal enterocytes is recognised as the major iron import protein. We investigated whether genetic variability within the DMT1 gene may partly explain the phenotypic variability seen amongst a group of C282Y homozygotes with iron overload. METHODS: One hundred and one unrelated C282Y homozygotes and 103 C282Y negative controls were analysed for the presence of four specific mutations/polymorphisms within the DMT1 gene (1245T/C, 1303C/A, IVS4 + 44C/A, IVS15Ex16-16C/G) using standard PCR techniques. Hepatic iron deposition was determined in 32 HH patients following Perls Prussian blue staining (0-4+). Estimations of the haplotype frequencies were performed utilising the program Arlequin version 2. RESULTS: There were no significant differences in the allele frequencies of the IVS4 + 44C/A, 1303C/A, 1254T/C and IVS15Ex16-16C/G polymorphisms in the patient cohort compared to those observed in the control cohort. The commonest haplotypes identified were CCTC: IVS4C + 44C, 1303C, 1254T, IVS15ex16-16C; ACCC: IVS4C + 44A, 1303C, 1254C, IVS15ex16-16C and ACTG: IVS4C + 44A, 1303C, 1254T, IVS15ex16-16G. Similarly, there were no significant differences in the frequencies of these three haplotypes in the patient cohorts (regardless of the degree of hepatic iron deposition) compared to the control cohort. CONCLUSIONS: Polymorphisms within DMT1 gene do not influence penetrance of the HH phenotype.

Adolescent↗