Economic evaluation of direct-acting antivirals for the treatment of genotype 3 hepatitis C infection in Singapore.

BACKGROUND AND AIM: The prohibitively high cost of direct-acting antivirals (DAA) for hepatitis C virus (HCV) infection remains a barrier to treatment access in Singapore. We aimed to evaluate whether DAA as first-line therapy would be cost-effective for genotype 3 (GT3) HCV patients compared with pegylated interferon and ribavirin (PR). METHODS: A decision tree analysis was used to compare the costs and outcomes of DAA and PR as first-line therapy. Treatment effectiveness, defined as sustained virological response, was assessed using a retrospective cohort of treated GT3 HCV patients. Direct medical costs were estimated from the payer's perspective using billing information. We obtained health utilities from published literature. We performed extensive one-way sensitivity analyses and probabilistic sensitivity analyses to account for uncertainties regarding the model parameters. RESULTS: In base case analysis, first-line therapy with DAA and PR yielded quality-adjusted life years (QALYs) of 0.69 and 0.62 at a cost of USD 54 634 and USD 23 857, respectively. The resultant incremental cost-effectiveness ratio (ICER) (USD 449 232/QALY) exceeded the willingness-to-pay threshold (USD 53 302/QALY). The ICER was robust for uncertainties regarding the model parameters. The cost of DAA is the key factor influencing the cost-effectiveness of HCV treatment. At current price, DAA as first-line therapy is not cost-effective compared with PR, with or without consideration of retreatment. Threshold analysis suggested that DAA can be cost-effective if it costs less than USD 17 002 for a 12-week treatment course. CONCLUSION: At current price, DAA as first-line therapy is not cost-effective compared with PR in GT3 HCV patients in Singapore.

Pan-cancer analysis of transcriptional metabolic dysregulation using The Cancer Genome Atlas.

Understanding metabolic dysregulation in different disease settings is vital for the safe and effective incorporation of metabolism-targeted therapeutics in the clinic. Here, using transcriptomic data for 10,704 tumor and normal samples from The Cancer Genome Atlas, across 26 disease sites, we present a novel bioinformatics pipeline that distinguishes tumor from normal tissues, based on differential gene expression for 114 metabolic pathways. We confirm pathway dysregulation in separate patient populations, demonstrating the robustness of our approach. Bootstrapping simulations were then applied to assess the biological significance of these alterations. We provide distinct examples of the types of analysis that can be accomplished with this tool to understand cancer specific metabolic dysregulation, highlighting novel pathways of interest, and patterns of metabolic flux, in both common and rare disease sites. Further, we show that Master Metabolic Transcriptional Regulators explain why metabolic differences exist, can segregate patient populations, and predict responders to different metabolism-targeted therapeutics.

IPI59: An Actionable Biomarker to Improve Treatment Response in Serous Ovarian Carcinoma Patients.

Despite improvements in operative management and therapies, overall survival rates in advanced ovarian cancer have remained largely unchanged over the past three decades. Although it is possible to identify high-risk patients following surgery, the knowledge does not provide information about the genomic aberrations conferring risk, or the implications for treatment. To address these challenges, we developed an integrative pathway-index model and applied it to messenger RNA expression from 458 patients with serous ovarian carcinoma from the Cancer Genome Atlas project. The biomarker derived from this approach, IPI59, contains 59 genes from six pathways. As we demonstrate using independent datasets from six studies, IPI59 is strongly associated with overall and progression-free survival, and also identifies high-risk patients who may benefit from enhanced adjuvant therapy.

Revealing complete complex KIR haplotypes phased by long-read sequencing technology.

The killer cell immunoglobulin-like receptor (KIR) region of human chromosome 19 contains up to 16 genes for natural killer (NK) cell receptors that recognize human leukocyte antigen (HLA)/peptide complexes and other ligands. The KIR proteins fulfill functional roles in infections, pregnancy, autoimmune diseases and transplantation. However, their characterization remains a constant challenge. Not only are the genes highly homologous due to their recent evolution by tandem duplications, but the region is structurally dynamic due to frequent transposon-mediated recombination. A sequencing approach that precisely captures the complexity of KIR haplotypes for functional annotation is desirable. We present a unique approach to haplotype the KIR loci using single-molecule, real-time (SMRT) sequencing. Using this method, we have-for the first time-comprehensively sequenced and phased sixteen KIR haplotypes from eight individuals without imputation. The information revealed four novel haplotype structures, a novel gene-fusion allele, novel and confirmed insertion/deletion events, a homozygous individual, and overall diversity for the structural haplotypes and their alleles. These KIR haplotypes augment our existing knowledge by providing high-quality references, evolutionary informers, and source material for imputation. The haplotype sequences and gene annotations provide alternative loci for the KIR region in the human genome reference GrCh38.p8.

Imetelstat, a telomerase inhibitor, differentially affects normal and malignant megakaryopoiesis.

Imetelstat (GRN163L) is a specific telomerase inhibitor that has demonstrated clinical activity in patients with myeloproliferative neoplasms (MPN) and in patients with solid tumors. The antitumor effects were associated with the development of thrombocytopenia, one of the common side effects observed in patients treated with imetelstat. The events underlying these adverse effects are not apparent. In this report, we investigated the potential mechanisms that account for imetelstat's beneficial effects in MPN patients and the manner by which imetelstat treatment leads to a reduction in platelet numbers. Using a well-established system of ex vivo megakaryopoiesis, we demonstrated that imetelestat treatment affects normal megakaryocyte (MK) development by exclusively delaying maturation of MK precursor cells. By contrast, additional stages along MPN MK development were affected by imetelstat resulting in reduced numbers of assayable colony-forming unit MK and impaired MK maturation. In addition, treatment with imetelstat inhibited the secretion of fibrogenic growth factors by malignant but not by normal MK. Our results indicate that the delay observed in normal MK maturation may account for imetelstat-induced thrombocytopenia, while the more global effects of imetelstat on several stages along the hierarchy of MPN megakaryopoiesis may be responsible for the favorable clinical outcomes reported in MPN patients.

Use of hematologic biomarkers during chemotherapy predicts survival in ovarian cancer patients.

OBJECTIVE: The optimal strategy for combining chemotherapy with immunotherapy in ovarian cancer patients is currently under investigation. Increasing evidence indicates that the lymphopenia induced by chemotherapy may promote homeostatic proliferation and thereby enhance antitumor immunity. Furthermore, there has been much discussion and even discord over the effects of anemia and blood transfusion in the perichemnotherapy period. The goals of this retrospective study were to determine the timing of chemotherapy induced lymphopenia and to observe perichemnotherapy hemoglobin levels, and the impact of the timing and depth of lymphopenia and anemia on clinical outcomes of ovarian cancer patients. MATERIALS AND METHODS: A chart review was performed on 115 patients identified in the electronic medical record from May 2005 until May 2011. Identified patients were only those who received at least six cycles of carboplatin and paclitaxel under the present authors' care for primary peritoneal, ovarian, or fallopian tube carcinoma. Specifically, the authors focused on lymphocyte and hemoglobin nadir and the reconstitution kinetics for this population. For each patient's lymphocyte count, nadir values were abstracted from weekly complete blood counts. They then split the population into two groups based on whether the nadir occurred at or after the nine-week mark (third cycle) for the lymphopenia data; this point was chosen because it was good for prognosis and it corresponds to patients whose trajectories bottom out. The intrachernotherapy hemoglobin levels were observed and an exploratory analysis was performed to attempt to identify a range that significantly effected patient outcomes. RESULTS: Lymiphocytes: The nadir of absolute lymphocyte concentrations is associated with platinum status and clinical response (Figure 1A). 94/115 patients had a lymphocyte count nadir after the third cycle of chemotherapy. 71/94 (75.5%) were platinum sensitive, 21/94 (22.3%) were resistant, and 2/94 (2.1%) were refractory. Of those that experienced a nadir before three cycles, ten (47.6%) were sensitive, ten (47.6%) were resistant, and one (4.7%) was refractory (p = 0.04). Considering nadir values continuously, both overall survival (OS,p = 0:0068) and progression free survival (PFS,p = 0:0321) were strongly associated with late nadir points. Twenty-one of the 115 patients had a nadir value earlier than the third draw and this was associated with progressive disease, platinum resistance, poor over- all survival, and poor progression free survival. The effect sizes were great [median 0S533 vs. 66 months median PFS, 14 vs. 38 months, early vs. late nadir respectively (Figure 11B)]. Hemzoglobin: A mean Hb less than 12.5 is associated with both overall survival (OS) (HR = 2.11, 95% CI: 1.03-4.33; p= 0:042) and progression free survival (PFS) (HR = 1.91, 95% CI: l.02-3.56; p= 0:041), as were low Hb level at outset of chemotherapy and a decreasing Hb trend over the course of treatment. Furthermore, for each cycle of chemotherapy in which the hemoglobin was recorded at avalue less than 11, hazard increased, with OS (HR = 3.51, 95% CI: 1.63-7.54, p = 0:0Ol3), and PFS (HR = 2.20, 95% CI:1.12-4.33; p = 0:0223). Deeper analysis revealed that outcomes were significantly affected when a pa- tient had three or more cycles with Hb less than 11 with both 05 (HR = 2.34, 95% Cl: 1.37-4.01; Wald-Test p = 0:0020, Log Rank p = 0.00145) and PFS (HR =1.88, 95% CI: 1. 17-3.02; Wald-Test p = 0:009, Log Rank p = 0.00743). CONCLUSION: The nadir of absolute lymphocyte concentrations is an independent predictor of overall survival and progression free survival. This is an easily measurable biomarker which can be utilized for identifying patients that will be likely to respond to immunomodulation. Furthermore, this evidence showing significant improvement in OS and PFS with two or less cycles with hemoglobin < 11 sheds new light on the need for further studies on growth stimulating factors and blood transfusion during this treatment period.

Stereological Analysis of Liver Biopsy Histology Sections as a Reference Standard for Validating Non-Invasive Liver Fat Fraction Measurements by MRI.

BACKGROUND AND AIMS: Validation of non-invasive methods of liver fat quantification requires a reference standard. However, using standard histopathology assessment of liver biopsies is problematical because of poor repeatability. We aimed to assess a stereological method of measuring volumetric liver fat fraction (VLFF) in liver biopsies and to use the method to validate a magnetic resonance imaging method for measurement of VLFF. METHODS: VLFFs were measured in 59 subjects (1) by three independent analysts using a stereological point counting technique combined with the Delesse principle on liver biopsy histological sections and (2) by three independent analysts using the HepaFat-Scan® technique on magnetic resonance images of the liver. Bland Altman statistics and intraclass correlation (IC) were used to assess the repeatability of each method and the bias between the methods of liver fat fraction measurement. RESULTS: Inter-analyst repeatability coefficients for the stereology and HepaFat-Scan® methods were 8.2 (95% CI 7.7-8.8)% and 2.4 (95% CI 2.2-2.5)% VLFF respectively. IC coefficients were 0.86 (95% CI 0.69-0.93) and 0.990 (95% CI 0.985-0.994) respectively. Small biases (≤3.4%) were observable between two pairs of analysts using stereology while no significant biases were observable between any of the three pairs of analysts using HepaFat-Scan®. A bias of 1.4±0.5% VLFF was observed between the HepaFat-Scan® method and the stereological method. CONCLUSIONS: Repeatability of the stereological method is superior to the previously reported performance of assessment of hepatic steatosis by histopathologists and is a suitable reference standard for validating non-invasive methods of measurement of VLFF.

The CD47 "don't eat me signal" is highly expressed in human ovarian cancer.

OBJECTIVES: The CD47 "don't eat me" signal allows tumor immune evasion. We tested the association of CD47 expression with outcomes in EOC. METHODS: CD47 expression was examined within the TCGA database for ovarian carcinoma. For validation, IHC was performed on a TMA consisting of specimens from 265 patients with EOC. The medical records of the patients were also retrospectively reviewed to correlate demographic and survival data. RESULTS: CD47 was amplified in 15/316 (5%) ovarian serous cancers in TCGA. In the validation cohort, the majority of patients had stage III/IV disease (208/265, 78.4%). CD47 expression was seen in 210/265 (79.2%). Patients were categorized into CD47hi (129/265; 48.7%) versus CD47lo (136/265; 51.3%). Patients with CD47lo tumors were more likely to have a complete response to adjuvant therapy than CD47hi (65% vs 50%, p=0.026). Although there was a trend towards an increase in median OS (37.64 vs 45.26months, p=0.92) in the CD47lo group compared with CD47hi, the difference was not significant. CONCLUSIONS: CD47 is expressed at high frequency in EOC. Patients with CD47lo EOC had a better treatment response to standard therapy, and trended towards improved OS. This demonstrates that while CD47 may be an immunologic shield that may be considered for targeted therapies, it is likely that it operates in concert with other mechanisms of immune evasion. Future studies to evaluate CD47 expression with other known mechanisms of immune escape in the tumor microenvironment may help further define its role.

Reduced Sensitivity to Charge Noise in Semiconductor Spin Qubits via Symmetric Operation.

We demonstrate improved operation of exchange-coupled semiconductor quantum dots by substantially reducing the sensitivity of exchange operations to charge noise. The method involves biasing a double dot symmetrically between the charge-state anticrossings, where the derivative of the exchange energy with respect to gate voltages is minimized. Exchange remains highly tunable by adjusting the tunnel coupling. We find that this method reduces the dephasing effect of charge noise by more than a factor of 5 in comparison to operation near a charge-state anticrossing, increasing the number of observable exchange oscillations in our qubit by a similar factor. Performance also improves with exchange rate, favoring fast quantum operations.

Identification of protein phosphatase 2A as an interacting protein of leucine-rich repeat kinase 2.

Mutations in the gene coding for the multi-domain protein leucine-rich repeat kinase 2 (LRRK2) are the leading cause of genetically inherited Parkinson's disease (PD). Two of the common found mutations are the R1441C and G2019S. In this study we identified protein phosphatase 2A (PP2A) as an interacting partner of LRRK2. We were able to demonstrate that the Ras of complex protein (ROC) domain is sufficient to interact with the three subunits of PP2A in human neuroblastoma SH-SY5Y cells and in HeLa cells. The alpha subunit of PP2A is interacting with LRRK2 in the perinuclear region of HeLa cells. Silencing the catalytic subunit of PP2A by shRNA aggravated cellular degeneration induced by the pathogenic R1441C-LRRK2 mutant expressed in neuroblastoma SH-SY5Y cells. A similar enhancement of apoptotic nuclei was observed by downregulation of the catalytic subunit of PP2A in cultured cortical cells derived from neurons overexpressing the pathogenic mutant G2019S-LRRK2. Conversely, pharmacological activation of PP2A by sodium selenate showed a partial neuroprotection from R1441C-LRRK2-induced cellular degeneration. All these data suggest that PP2A is a new interacting partner of LRRK2 and reveal the importance of PP2A as a potential therapeutic target in PD.

Docetaxel and nab-paclitaxel are safe alternative options for patients with gynecologic malignancies following hypersensitivity reaction to paclitaxel.

Docetaxel and nab-paclitaxel are safe alternatives to paclitaxel after hypersensitivity reaction occurs. There was no significant difference in overall survival between those that had paclitaxel, docetaxel, and nab-paclitaxel.

Large-scale assessment of polyglutamine repeat expansions in Parkinson disease.

OBJECTIVES: We aim to clarify the pathogenic role of intermediate size repeat expansions of SCA2, SCA3, SCA6, and SCA17 as risk factors for idiopathic Parkinson disease (PD). METHODS: We invited researchers from the Genetic Epidemiology of Parkinson's Disease Consortium to participate in the study. There were 12,346 cases and 8,164 controls genotyped, for a total of 4 repeats within the SCA2, SCA3, SCA6, and SCA17 genes. Fixed- and random-effects models were used to estimate the summary risk estimates for the genes. We investigated between-study heterogeneity and heterogeneity between different ethnic populations. RESULTS: We did not observe any definite pathogenic repeat expansions for SCA2, SCA3, SCA6, and SCA17 genes in patients with idiopathic PD from Caucasian and Asian populations. Furthermore, overall analysis did not reveal any significant association between intermediate repeats and PD. The effect estimates (odds ratio) ranged from 0.93 to 1.01 in the overall cohort for the SCA2, SCA3, SCA6, and SCA17 loci. CONCLUSIONS: Our study did not support a major role for definite pathogenic repeat expansions in SCA2, SCA3, SCA6, and SCA17 genes for idiopathic PD. Thus, results of this large study do not support diagnostic screening of SCA2, SCA3, SCA6, and SCA17 gene repeats in the common idiopathic form of PD. Likewise, this largest multicentered study performed to date excludes the role of intermediate repeats of these genes as a risk factor for PD.

Undoped accumulation-mode Si/SiGe quantum dots.

We report on a quantum dot device design that combines the low disorder properties of undoped SiGe heterostructure materials with an overlapping gate stack in which each electrostatic gate has a dominant and unique function-control of individual quantum dot occupancies and of lateral tunneling into and between dots. Control of the tunneling rate between a dot and an electron bath is demonstrated over more than nine orders of magnitude and independently confirmed by direct measurement within the bandwidth of our amplifiers. The inter-dot tunnel coupling at the [Formula: see text] charge configuration anti-crossing is directly measured to quantify the control of a single inter-dot tunnel barrier gate. A simple exponential dependence is sufficient to describe each of these tunneling processes as a function of the controlling gate voltage.

Texture-based classification of liver fibrosis using MRI.

PURPOSE: To investigate the ability of texture analysis of MRI images to stage liver fibrosis. Current noninvasive approaches for detecting liver fibrosis have limitations and cannot yet routinely replace biopsy for diagnosing significant fibrosis. MATERIALS AND METHODS: Forty-nine patients with a range of liver diseases and biopsy-confirmed fibrosis were enrolled in the study. For texture analysis all patients were scanned with a T2 -weighted, high-resolution, spin echo sequence and Haralick texture features applied. The area under the receiver operating characteristics curve (AUROC) was used to assess the diagnostic performance of the texture analysis. RESULTS: The best mean AUROC achieved for separating mild from severe fibrosis was 0.81. The inclusion of age, liver fat and liver R2 variables into the generalized linear model improved AUROC values for all comparisons, with the F0 versus F1-4 comparison the highest (0.91). CONCLUSION: Our results suggest that a combination of MRI measures, that include selected texture features from T2 -weighted images, may be a useful tool for excluding fibrosis in patients with liver disease. However, texture analysis of MRI performs only modestly when applied to the classification of patients in the mild and intermediate fibrosis stages.

Breathprints of childhood obesity: changes in volatile organic compounds in obese children compared with lean controls.

OBJECTIVE: The objective of this study was to investigate changes in volatile organic compounds (VOCs) in exhaled breath in overweight/obese children compared with their lean counterparts. STUDY DESIGN: Single exhaled breath was collected and analyzed per protocol using selective ion flow tube mass spectrometry (SIFT-MS). RESULTS: Sixty overweight/obese children and 55 lean controls were included. Compared with the lean group, the obese group was significantly older (14.1 ± 2.8 vs. 12.1 ± 3.0 years), taller (164.8 ± 10.9 vs. 153.3 ± 17.1 cm) and more likely to be Caucasian (60% vs. 35.2%); P < 0.05 for all. A comparison of the SIFT-MS results of the obese group with the lean group revealed differences in concentration of more than 50 compounds. A panel of four VOCs can identify the presence of overweight/obesity with excellent accuracy. Further analysis revealed that breath isoprene, 1-decene, 1-octene, ammonia and hydrogen sulfide were significantly higher in the obese group compared with the lean group (P value < 0.01 for all). CONCLUSION: Obese children have a unique pattern of exhaled VOCs. Changes in VOCs observed in this study may help to gain insight into pathophysiological processes and pathways leading to the development of childhood obesity.

Analysis of the intrahepatic ductular reaction and progenitor cell responses in hepatitis C virus recurrence after liver transplantation.

Fibrosis in livers with hepatitis C virus (HCV) recurrence after liver transplantation (LT) can be rapidly progressive, and the mechanisms underlying this process are poorly understood. In livers with HCV infections in the non-LT setting, there is a significant relationship between the development of structures known as the ductular reaction (DR), hepatic progenitor cells (HPCs), and fibrosis. This study characterizes the DR, HPCs, and fibrosis associated with HCV recurrence after LT. Immunohistochemistry and confocal microscopy were used to characterize the DR, HPC, and fibrosis in liver biopsy specimens. Key findings were confirmed in a separate, independent cohort. The initial characterization cohort had 194 biopsy samples from 105 individuals with HCV recurrence after LT. The immunophenotype, morphology, and location of the DR were consistent with an HPC origin. The DR correlated with intrahepatic fibrosis (rs = 0.529, P < 0.001) and the number of activated hepatic stellate cells (HSCs; rs = 0.446, P < 0.001). There was an early occurrence of hepatocyte replicative arrest as well as increased hepatocyte proliferation that correlated with the DR (rs = 0.295, P < 0.001). Replicative arrest preceded hepatocyte proliferation in early-stage injury. Hepatocyte proliferation decreased with advanced fibrosis; in contrast, the extent of the DR and the number of activated HSCs continued to increase. In the second cohort of 37 individuals, the DR and the number of HPCs similarly correlated with fibrosis and inflammation after LT. In conclusion, this is the first characterization of the DR in HCV-associated liver injury after LT. There was a significant correlation between the DR and the development of progressive fibrosis in HCV recurrence. These results suggest a pivotal role for both the DR and the HPC responses in the aggressive fibrosis seen with HCV recurrence after LT.

High histone variant H3.3 content in mouse prospermatogonia suggests a role in epigenetic reformatting.

Histone variants can incorporate into the nucleosome outside of S-phase. Some are known to play important roles in mammalian germ cell development, this cell lineage being characterized by long phases of quiescence, a protracted meiotic phase, and genome-wide epigenetic reformatting events. The best known example of such an event is the global-scale erasure of DNA methylation in sexually indifferent primordial germ cells, then its re-establishment in fetal prospermatogonia and growing oocytes. Histone H3 and its post-translationally modified forms provide important waypoints in the establishment of epigenetic states. Using mass spectrometry and immunoblotting, we show that the H3.3 replacement variant is present at an unusually high amount in mouse prospermatogonia at the peak stage of global DNA methylation re-establishment. We speculate that H3.3 facilitates this process through achieving a greater level of accessibility of chromatin modifiers to DNA.

Metabolomic analysis of breath volatile organic compounds reveals unique breathprints in children with inflammatory bowel disease: a pilot study.

BACKGROUND: Breath testing is becoming an important diagnostic method to evaluate many disease states. In the light of rising healthcare costs, is important to develop a simple non-invasive tool to potentially identify paediatric patients who need endoscopy for suspected inflammatory bowel disease (IBD). AIM: To analyse exhaled volatile organic compounds (VOCs) and investigate the presence of a unique breath patterns to differentiate paediatric patients with (IBD) from healthy controls. METHODS: A cross-sectional, single-centre study included paediatric IBD patients and healthy controls (age range, 5-21 years). The diagnosis of IBD was confirmed by endoscopic, histological and radiographic data. Exhaled breath was collected and analysed using a selective ion flow tube mass spectroscopy (SIFT-MS) to identify new markers or patterns of IBD. RESULTS: One hundred and seventeen patients (62 with IBD and 55 healthy controls) were included in the study. Linear discriminant analysis and principle component analysis of mass scanning ion peak data demonstrated 21 pre-selected VOCs correctly classify patients with IBD or as healthy controls; P < 0.0001. Multivariable logistic regression analysis further showed three specific VOCs (1-octene, 1-decene, (E)-2-nonene) had excellent accuracy for predicting the presence of IBD with an area under the curve (AUC) of 0.96 (95% CI: 0.93-0.99). No significant difference in VOCs was found between patients with Crohn's disease or ulcerative colitis, and no significant correlation was seen with disease activity. CONCLUSION: These pilot data support the hypothesis that a unique breathprint potentially exists for paediatric IBD in the exhaled metabolome.

Diagnostic performance of a rapid magnetic resonance imaging method of measuring hepatic steatosis.

OBJECTIVES: Hepatic steatosis is associated with an increased risk of developing serious liver disease and other clinical sequelae of the metabolic syndrome. However, visual estimates of steatosis from histological sections of biopsy samples are subjective and reliant on an invasive procedure with associated risks. The aim of this study was to test the ability of a rapid, routinely available, magnetic resonance imaging (MRI) method to diagnose clinically relevant grades of hepatic steatosis in a cohort of patients with diverse liver diseases. MATERIALS AND METHODS: Fifty-nine patients with a range of liver diseases underwent liver biopsy and MRI. Hepatic steatosis was quantified firstly using an opposed-phase, in-phase gradient echo, single breath-hold MRI methodology and secondly, using liver biopsy with visual estimation by a histopathologist and by computer-assisted morphometric image analysis. The area under the receiver operating characteristic (ROC) curve was used to assess the diagnostic performance of the MRI method against the biopsy observations. RESULTS: The MRI approach had high sensitivity and specificity at all hepatic steatosis thresholds. Areas under ROC curves were 0.962, 0.993, and 0.972 at thresholds of 5%, 33%, and 66% liver fat, respectively. MRI measurements were strongly associated with visual (r(2) = 0.83) and computer-assisted morphometric (r(2) = 0.84) estimates of hepatic steatosis from histological specimens. CONCLUSIONS: This MRI approach, using a conventional, rapid, gradient echo method, has high sensitivity and specificity for diagnosing liver fat at all grades of steatosis in a cohort with a range of liver diseases.

Disruption of hemochromatosis protein and transferrin receptor 2 causes iron-induced liver injury in mice.

UNLABELLED: Mutations in hemochromatosis protein (HFE) or transferrin receptor 2 (TFR2) cause hereditary hemochromatosis (HH) by impeding production of the liver iron-regulatory hormone, hepcidin (HAMP). This study examined the effects of disruption of Hfe or Tfr2, either alone or together, on liver iron loading and injury in mouse models of HH. Iron status was determined in Hfe knockout (Hfe(-/-)), Tfr2 Y245X mutant (Tfr2(mut)), and double-mutant (Hfe(-/-) ×Tfr2(mut) ) mice by measuring plasma and liver iron levels. Plasma alanine transaminase (ALT) activity, liver histology, and collagen deposition were evaluated to assess liver injury. Hepatic oxidative stress was assessed by measuring superoxide dismutase (SOD) activity and F(2)-isoprostane levels. Gene expression was measured by real-time polymerase chain reaction. Hfe(-/-) ×Tfr2(mut) mice had elevated hepatic iron with a periportal distribution and increased plasma iron, transferrin saturation, and non-transferrin-bound iron, compared with Hfe(-/-), Tfr2(mut), and wild-type (WT) mice. Hamp1 expression was reduced to 40% (Hfe(-/-) and Tfr2(mut) ) and 1% (Hfe(-/-) ×Tfr2(mut)) of WT values. Hfe(-/-) ×Tfr2(mut) mice had elevated plasma ALT activity and mild hepatic inflammation with scattered aggregates of infiltrating inflammatory cluster of differentiation 45 (CD45)-positive cells. Increased hepatic hydoxyproline levels as well as Sirius red and Masson's Trichrome staining demonstrated advanced portal collagen deposition. Hfe(-/-) and Tfr2(mut) mice had less hepatic inflammation and collagen deposition. Liver F(2) -isoprostane levels were elevated, and copper/zinc and manganese SOD activities decreased in Hfe(-/-) ×Tfr2(mut), Tfr2(mut), and Hfe(-/-) mice, compared with WT mice. CONCLUSION: Disruption of both Hfe and Tfr2 caused more severe hepatic iron overload with more advanced lipid peroxidation, inflammation, and portal fibrosis than was observed with the disruption of either gene alone. The Hfe(-/-) ×Tfr2(mut) mouse model of iron-induced liver injury reflects the liver injury phenotype observed in human HH.