OBJECTIVE

Transient elastography (FibroScan) is a novel, noninvasive, rapid bedside method to assess liver fibrosis by measuring liver stiffness in adult patients. The usefulness of FibroScan in children with chronic liver diseases is unknown. The aim of this prospective study was to evaluate the feasibility of liver stiffness measurement and to compare FibroScan, Fibrotest, and aspartate transaminase to platelets ratio index (APRI) with liver biopsy for the diagnosis of cirrhosis in children with chronic liver diseases.

METHODS

Between February 2004 and October 2005, 116 consecutive children with chronic liver diseases were prospectively included. All except 1 child (58 boys, mean age 10.7 years) could have noninvasive tests for fibrosis: FibroScan, Fibrotest, and APRI, and, when necessary, a liver biopsy (n = 33).

RESULTS

FibroScan, Fibrotest, and APRI were correlated with clinical or biological parameters of chronic liver diseases, but the FibroScan marker correlated most with all parameters. By histology, the METAVIR fibrosis category score was F1 in 7 cases, F2 in 8 cases, F3 in 6 cases, and F4 in 12 cases. FibroScan, Fibrotest, and APRI were significantly correlated with the METAVIR fibrosis score. For the diagnosis of cirrhosis, the area under the receiver operating characteristic curve was 0.88, 0.73, and 0.73 for FibroScan, Fibrotest, and APRI, respectively.

CONCLUSIONS

These results indicate that liver stiffness measurement is feasible in children and is related to liver fibrosis. A specific probe dedicated to children and slender patients has thus been developed and is currently under evaluation. The FibroScan equipped with this specific probe could become a useful tool for the management of chronic liver diseases in children.

A meta-analysis was performed to assess and compare the accuracies of magnetic resonance elastography (MRE) and diffusion-weighted imaging (DWI) for the staging of hepatic fibrosis. Online journal databases and a manual search from January 2000 to May 2011 were used. We identified 41 studies, but only 14 met the criteria to perform a meta-analysis assessing MRE (five trials) or DWI (10 trials). Fibrosis was categorized by redistribution into five stages according to histopathological description. A bivariate binomial model was used to combine the sensitivity and specificity and their 95% confidence intervals (CIs), from which diagnostic odds ratio (DOR), positive likelihood ratio (PLR), negative likelihood ratio (NLR), and summary receiver operating characteristic (sROC) were derived to indicate the diagnostic accuracy of imaging modalities. With MRE, the sensitivity, specificity, DOR, PLR, NLR, and area under sROC curve (with 95% CIs) for staging F0 ∼ F1 versus F2 ∼ F4 and F0 ∼ F2 versus F3 ∼ F4 were 0.94 (0.81-0.98), 0.95 (0.87-0.98), 20 (7-57), 0.06 (0.02-0.22), 317 (55-1,796), 0.98 (0.97-0.99) and 0.92 (0.85-0.96), 0.96 (0.91-0.98), 21 (10-45), 0.08 (0.04-0.16), 251 (103-609), and 0.98 (0.96-0.99), respectively; and with DWI, these values were 0.77 (0.71-0.82), 0.78 (0.69-0.85), 3 (2-5), 0.30 (0.22-0.40), 12 (6-21), 0.83 (0.79-0.86) and 0.72 (0.60-0.81), 0.84 (0.77-0.89), 5 (3-7), 0.34 (0.23-0.50), 13 (6-29), and 0.86 (0.83-0.89), respectively. A z test demonstrated that MRE had a significantly higher accuracy than DWI in those indicators (P < 0.05).

CONCLUSIONS

MRE is more reliable for staging hepatic fibrosis, compared with DWI, with a high combination of sensitivity, specificity, likelihood ratios, DOR, and area under sROC curve.

We have characterized a growth factor inducible gene, N10, encoding a nuclear protein of 601 amino acids with a significant similarity to members of the steroid and thyroid hormone receptor families. The gene is rapidly but transiently induced by several mitogens. Immunoprecipitation studies show that the N10 protein is transiently expressed after stimulation of quiescent cells, presenting a half-life of approximately 30 min. The N10 transcription unit is 8 kb in length, split into seven exons. The exon-intron distribution is in general similar to that of other members of the nuclear receptor superfamily, but presents some differences which suggest that N10 belongs to a new family of these molecules. The 5' flanking region contains one DSE which could explain its immediate response to external stimulus. The N10 gene is located in the [F1-F3] region of mouse chromosome 15.

OBJECTIVE

The molecular mechanisms of hepatocellular carcinoma have been studied, but little is known of the changes in liver gene expression during the different stages of chronic hepatitis C virus (HCV) infection, in particular the transition from mild to moderate fibrosis.

METHODS

We used real-time quantitative RT PCR to study the messenger RNA expression of 240 selected genes in 2 pools of liver specimens according to the stages of fibrosis (Metavir score; mild fibrosis = F1 and septal fibrosis = F2). Genes whose expression differed between pools (F2 vs F1) by at least 2-fold were selected. In addition, the expression level of these selected genes then was assessed in each of the 62 individual samples (F4, n = 6; F3, n = 17; F2, n = 21; vs F1, n = 18).

RESULTS

The 22 genes that were up-regulated in the 21 F2 samples relative to the 18 F1 samples mainly encoded genes involved in cytoskeleton (KRT 19 and SCG 10), growth factors/cytokines (CXCL6, interleukin 8 [IL8], IL1A, IL2, and CXCL10), or growth factor receptors (CCR2, CXCR3, and CXCR4), or were involved in extracellular matrix production (COL1A1, CHI3L, and SPP1), in extracellular matrix remodeling (TIMP1, MMP7, and MMP9), and in cell junction (ITGA2 and CLDN 4). When hierarchically clustering the F2 and F1 samples according to the expression of the 11 most discriminatory genes (KRT 19, COL1A1, STMN2, CXCL6, CCR2, TIMP1, IL8, IL1A, ITGA2, CLDN 4, and IL2), the patient population was categorized into 2 subgroups: F1 and F2. Specifically, 15 of 18 F1 (83%) and 19 of 21 F2 (90%) were classified correctly (P < 10(-5)). We also studied the messenger RNA expression of these 240 selected genes in normal liver in comparison with F1. Genes dysregulated in the transition from normal liver to F1 mainly were interferon-inducible genes, and therefore were very different from those dysregulated in the transition from F1 to F2.

CONCLUSIONS

Genes involved in extracellular matrix turnover and immune response are implicated in the transition from mild to moderate fibrosis. Eleven of the genes could form the basis for the gene expression signature of mild versus moderate fibrosis in patients with chronic hepatitis C.

OBJECTIVE

To investigate the diagnostic accuracy of acoustic radiation force impulse (ARFI) imaging as a noninvasive method for the assessment of liver fibrosis in chronic hepatitis C (CHC) patients.

METHODS

We performed a prospective blind comparison of ARFI elastography, APRI index and FibroMax in a consecutive series of patients who underwent liver biopsy for CHC in University Hospital Bucharest. Histopathological staging of liver fibrosis according to the METAVIR scoring system served as the reference. A total of 74 patients underwent ARFI elastography, APRI index, FibroMax and successful liver biopsy.

RESULTS

The noninvasive tests had a good correlation with the liver biopsy results. The most powerful test in predicting fibrosis was ARFI elastography. The diagnostic accuracy of ARFI elastography, expressed as area under receiver operating characteristic curve (AUROC) had a validity of 90.2% (95% CI AUROC = 0.831-0.972, P < 0.001) for the diagnosis of significant fibrosis (F>>or= 2). ARFI sonoelastography predicted even better F3 or F4 fibrosis (AUROC = 0.993, 95% CI = 0.979-1).

CONCLUSIONS

ARFI elastography had very good accuracy for the assessment of liver fibrosis and was superior to other noninvasive methods (APRI Index, FibroMax) for staging liver fibrosis.

OBJECTIVE

Histological examination of liver biopsy is currently required in the management of patients with chronic hepatitis C. Our aim was to evaluate the diagnostic utility of a panel of circulating markers in detecting the stage of fibrosis.

METHODS

One hundred and ninety four-patients who had undergone a percutaneous liver biopsy before antiviral treatment, and 194 age- and sex-matched healthy subjects were studied. Serum levels of hyaluronate, procollagen type III N-terminal peptide (PIIINP), matrix metalloproteinases (MMP)-1, MMP-2, MMP-9 and their tissue inhibitors of metalloproteinases (TIMP)-1 and TIMP-2 were determined by RIA and ELISA. Histological lesions were staged according to the METAVIR score.

RESULTS

Hyaluronate, PIIINP, TIMP-1, and TIMP-2 serum levels were significantly higher in patients than in controls. Six markers were significantly correlated with fibrosis: MMP-2 (r = 0.28; p < 0.01), TIMP-1 (r = 0.42; p < 0.001), HA (r = 0.50; p < 0.001), PIIINP (r = 0.62; p < 0.0001), MMP-1 (r = -0.32; p < 0.01), and MMP-9 (r = -0.22; p < 0.05). By multivariate analysis, only PIIINP and MMP-1 were independently associated with fibrosis, and were combined using the equation of the logistic regression model. Using receiver-operating characteristics analysis, the area under the curve of the score to discriminate mild (FO/F1) from significant fibrosis (F2/F3/F4) was 0.82, with a sensitivity of 60% for a specificity of 92%.

CONCLUSIONS

Our results suggest that combining two serum markers reflecting fibrogenesis (PIIINP) and fibrolysis (MMP-1) may provide a useful tool for evaluating liver fibrosis.

Cognitive performance, including performance on working memory (WM) tasks declines with age. Changes in brain activations are one presumed contributor to WM decline in the healthy aging population. In particular, neuroimaging studies show that when older adults perform WM tasks there tends to be greater bilateral frontal activity than in younger adults. We hypothesized that stimulating the prefrontal cortex in healthy older adults would improve WM performance. To test this hypothesis we employed transcranial direct current stimulation (tDCS), a neurostimulation technique in which small amounts of electrical current are applied to the scalp with the intent of modulating the activity in underlying neurons. Across three testing sessions we applied sham stimulation or anodal tDCS to the left (F3) or right (F4) prefrontal cortex to healthy older adults as they performed trials of verbal and visual 2-back WM tasks. Surprisingly, tDCS was uniformly beneficial across site and WM task, but only in older adults with more education. In the less educated group, tDCS provided no benefit to verbal or visual WM performance. We interpret these findings as evidence for differential frontal recruitment as a function of strategy when older adults perform WM tasks.

Transcriptional activation is associated commonly with recruitment of histone acetylases, while repression involves histone deacetylases (HDACs). Here, we provide evidence to suggest that STAT5 activates gene expression by recruiting HDAC. The interleukin-3 (IL-3)-dependent expression of the Id-1 gene, encoding a helix-loop-helix (HLH) transcriptional inhibitor, is activated by both C/EBPbeta and STAT5 transcription factors bound to its pro-B-cell enhancer (PBE), but is inhibited by HDAC inhibitors in Ba/F3 cells. STAT5 interacts with HDAC1 in the PBE region, resulting in deacetylation of histones, as well as C/EBPbeta, whose acetylation diminishes its DNA-binding activity. Consistently, expression of an acetylation-resistant mutant of C/EBPbeta results in IL-3-independent expression of the Id-1 gene. Thus, we propose a novel mechanism by which STAT5 mediates the deacetylation of C/EBPbeta, allowing transcriptional activation.

FLT3 kinase internal tandem duplication (ITD) mutations are common in acute myeloid leukemia (AML) and are associated with poor clinical outcomes. Although initial responses to FLT3 tyrosine kinase inhibitors (TKIs) are observed in FLT3-ITD-positive patients, subsequent relapse often occurs upon acquisition of secondary FLT3 kinase domain (KD) mutations, primarily at residues D835 and F691. Using biochemical assays, we determined that crenolanib, a novel TKI, demonstrates type I properties and is active against FLT3 containing ITD and/or D835- or F691-activating mutations. Potent activity was observed in FLT3-ITD-positive AML cell lines. Crenolanib delayed the outgrowth of MV4-11 cells in a xenograft mouse model, whereas in combination with the type II TKI sorafenib, a significant decrease in leukemic burden (P < .001) and prolonged survival (P < .01) was observed compared with either type I or II TKI alone. Crenolanib was active against Ba/F3 cells harboring FLT3-ITD and secondary KD mutations and sorafenib-resistant MOLM-13 cells containing FLT3-ITD/D835Y both in vitro and in vivo. In addition, crenolanib inhibited drug-resistant AML primary blasts with FLT3-ITD and D835H/Y mutations. These preclinical data demonstrate that crenolanib is effective against FLT3-ITD containing secondary KD mutations, suggesting that crenolanib may be a useful therapeutic agent for TKI-naive and drug-resistant FLT3-ITD-positive AML.

BACKGROUND

This study investigated the relationship of clinical, neuropsychological, and electrophysiological measures of prefrontal dysfunction with treatment response in elderly patients with major depression.

METHODS

Forty-nine depressed elderly subjects were studied before and after 6 weeks of adequate antidepressant treatment and compared with 22 psychiatrically normal controls. The psychomotor retardation item of the Hamilton Depression Rating Scale, the initiation/perseveration subscore of the Mattis Dementia Rating Scale, and the latency of the P300 auditory evoked potential were used as indices of prefrontal dysfunction. The intensity of antidepressant drug treatment was classified and monitored for a 6-week period.

RESULTS

Abnormal initiation/perseveration score, psychomotor retardation, and long P300 latency predicted 58% of the variance in change of depression scores from baseline to 6 weeks (F3= 20.1, P<.001). Depressed patients who remained symptomatic (n = 25) had more abnormal initiation/perseveration scores and longer P300 latency compared with depressed patients who achieved remission (n = 24) and control subjects. There were no differences between the last 2 groups. The association between psychomotor retardation, initiation/perseveration scores, P300 latency, and response to antidepressant treatment could not be explained by differences in demographic and clinical characteristics or treatment intensity between remitted and nonremitted depressed patients.

CONCLUSIONS

Prefrontal dysfunction was associated with poor or delayed antidepressant response in depressed elderly patients. This observation, if confirmed, may aid clinicians in identifying candidates for aggressive somatic therapies and for interventions offering structure of daily activities.

Human metapneumovirus (HMPV) is a recently recognized causative agent of respiratory tract disease in individuals of all ages and especially young infants. HMPV remains poorly characterized and has been reported to replicate inefficiently in vitro. Complete consensus sequences were recently determined for two isolates representing the two proposed HMPV genetic subgroups. We have developed a reverse genetic system to produce one of these isolates, CAN97-83, entirely from cDNA. We also recovered a version, rHMPV-GFP, in which the enhanced green fluorescent protein (GFP) was expressed from a transcription cassette inserted as the first gene, leaving the 41-nt leader region and first 16 nt of the N gene undisturbed. The ability to monitor GFP expression in living cells greatly facilitated the initial recovery of this slow-growing virus. In addition, the ability to express a foreign gene from an engineered transcription cassette confirmed the identification of the HMPV transcription signals and identified the F gene-end signal as being highly efficient for transcription termination. The ability to recover virus containing a foreign insert in this position indicated that the viral promoter is contained within the 3'-terminal 57 nt of the genome. Recombinant HMPV replicated in vitro as efficiently as biologically derived HMPV, whereas the kinetics and final yield of rHMPV-GFP were reduced several-fold. Conditions for trypsin treatment were investigated, providing for improved virus yields. Another version of HMPV, rHMPV+G1F23, was recovered that contained a second copy of the G gene and two extra copies of F in promoter-proximal positions in the order G1-F2-F3. Thus, this recombinant genome would encode 11 mRNAs rather than eight and would be 17.3 kb long, 30% longer than that of the natural virus. Nonetheless, the rHMPV+G1F23 virus replicated in vitro with an efficiency that was only modestly reduced compared to rHMPV and was essentially the same as rHMPV-GFP. Northern blot analysis showed that the increased number and promoter-proximal location of the added copies of the F and G genes resulted in a more than 6- and 14-fold increase in the expression of F and G mRNA, respectively, and sequence analysis confirmed the intactness of the added genes in recovered virus. Thus, it should be feasible to construct an HMPV vaccine virus containing extra copies of the G and F putative protective antigen genes to increase antigen expression or to provide representation of additional antigenic lineages or subgroups of HMPV.

OBJECTIVE

To examine if serum fibrosis biomarkers could accurately identify the stage of liver disease amongst hepatitis C (HCV) and HIV co-infected patients.

METHODS

One hundred and thirty seven HIV/HCV co-infected persons were randomly selected from the Johns Hopkins HIV Clinic cohort. Ninety five had complete testing for fibrosis markers in sera collected at the time of liver biopsy. Biopsies were scored according to Ishak modified histological activity index (F0 no fibrosis to F6 cirrhosis). Fibrosis was evaluated against alanine aminotransferase (ALT), aspartate aminotransferase (AST), AST to platelet ratio (APRI), albumin, total bilirubin, hyaluronic acid (HA) and YKL-40.

RESULTS

Sixty nine (73%) had no or minimal portal fibrosis (F0-2) and were compared with remaining subjects (F3-6). Fibrosis scores>> or =F3 were found 27 times more often in persons with HA levels >86 ng/ml and 5.5 times more often in persons with HA levels 41-86 ng/ml. Less substantial associations were detected with levels of albumin <3.5 g/dl (OR 4.85) and AST >60 iu (OR 5.91). All 35 subjects who had favorable results of HA, albumin, and AST had minimal fibrosis (F0-2).

CONCLUSIONS

Amongst HIV/HCV co-infected patients, serum testing for HA, albumin, and AST (SHASTA Index) was able to accurately stage mild and advanced fibrosis.

In many cell types, glycosylphosphatidylinositol (GPI)-anchored proteins are sequestered in detergent-resistant membrane rafts. These are plasma membrane microdomains enriched in glycosphingolipids and cholesterol and are suggested to be platforms for cell signaling. Concomitant with the synthesis of myelin glycosphingolipids, maturing oligodendrocytes progressively associate GPI-anchored proteins, including the adhesion molecules NCAM 120 and F3, in rafts. Here we show that these microdomains include Fyn and Lyn kinases. Both kinases are maximally active in myelin prepared from young animals, correlating with early stages of myelination. In the rafts, Fyn kinase is tightly associated with NCAM 120 and F3. In contrast, in oligodendrocyte progenitor cells lacking rafts or in raft-free membrane domains of more mature cells, F3 does not associate with Fyn. The addition of anti-F3 antibodies to oligodendrocytes results in stimulation of Fyn kinase specifically in rafts. Compartmentation of oligodendrocyte GPI-anchored proteins in rafts is thus a prerequisite for association with Fyn, permitting kinase activation. Interaction of oligodendrocyte F3 with axonal ligands such as L1 and ensuing kinase activation may play a crucial role in initiating myelination.

Non-invasive fibrosis scores are widely used to identify/exclude advanced fibrosis in patients with non-alcoholic fatty liver disease (NAFLD). However, these scores were principally developed and validated in patients aged between 35 and 65 years of age. The objective of this study was to assess the effect of age on the performance of non-invasive fibrosis tests in NAFLD.

Patients were recruited from European specialist hepatology clinics. The cohort was divided into five age-based groups: ≤35 (n=74), 36-45 (n=96), 46-55 (n=197), 56-64 (n=191), and ≥65 years (n=76), and the performance of the aspartate aminotransferase (AST)/alanine transaminase (ALT) ratio, fibrosis 4 (FIB-4), and NAFLD fibrosis score (NFS) for advanced fibrosis (stage F3-F4) for each group was assessed using liver biopsy as the standard.

Six hundred and thirty-four patients were included. The diagnostic accuracy of the AST/ALT ratio was lower than NFS and FIB-4 in all the age groups. The AST/ALT ratio, NFS, and FIB-4 score performed poorly for a diagnosis of advanced fibrosis in those aged ≤35 years (area under the receiver operating characteristic curves (AUROCs 0.52, 0.52, and 0.60, respectively). For all groups >35 years, AUROCs for advanced fibrosis were similar for the NFS and FIB-4 score (range 0.77-0.84). However, the specificity for advanced fibrosis using the FIB-4 and NFS declined with age, becoming unacceptably low in those aged ≥65 years (35% for FIB-4 and 20% for NFS). New cutoffs were derived (and validated) for those aged ≥65 years, which improved specificity to 70% without adversely affecting sensitivity (FIB-4 2.0, sensitivity 77%; NFS 0.12, sensitivity 80%).

The NFS and FIB-4 scores have similar accuracy for advanced fibrosis in patients aged >35 years. However, the specificity for advanced fibrosis is unacceptably low in patients aged ≥65 years, resulting in a high false positive rate. New thresholds for use in patients aged ≥65 years are proposed to address this issue.

BACKGROUND

The long-term efficacy and safety of the endoscopic injection of N-butyl-2-cyanoacrylate (Histoacryl) were evaluated to define its role as the initial treatment for bleeding gastric varices.

METHODS

Ninety patients with bleeding gastric varices underwent endoscopic injections of Histoacryl for hemostasis within a 6-year period. Histoacryl was injected intravariceally as a 1:1 mixture with Lipiodol. Among the 90 patients, 5 had active bleeding and 85 had recent bleeding. Most of the varices were large (F2 or F3, 85 cases). The most common locations were the fundus and the posterior wall of the proximal body (94.4%). After Histoacryl injection, patients were followed endoscopically with retreatment as necessary.

RESULTS

The rate of hemostasis at 1 week was 94.4%. Recurrent bleeding occurred in 23.3% of the patients from 3 days to 16 months after the initial injection. Recurrent bleeding was stopped with reinjections of Histoacryl in 16.7% of the patients. The rate of definitive hemostasis was 93.3% (84 of 90). The treatment failure-related mortality rate was 2.2% (2 of 90). To date, 35 patients have died, mostly as a result of malignancy or liver failure, and 55 are still alive. The determining factor for long-term survival was the underlying disease leading to portal hypertension. There were few long-term complications except for Histoacryl cast extrusion-related mucosal defects.

CONCLUSIONS

Endoscopic injection of Histoacryl is highly effective for the treatment of bleeding gastric varices, with rare complications both acutely and long term. This treatment modality is appropriate as the first choice for bleeding gastric varices.

Recently, treatment with bromodomain and extraterminal protein antagonist (BA) such as JQ1 has been shown to inhibit growth and induce apoptosis of human acute myelogenous leukemia (AML) cells, including those expressing FLT3-ITD. Here, we demonstrate that cotreatment with JQ1 and the FLT3 tyrosine kinase inhibitor (TKI) ponatinib or AC220 synergistically induce apoptosis of cultured and primary CD34(+) human AML blast progenitor cells (BPC) expressing FLT3-ITD. Concomitantly, as compared with each agent alone, cotreatment with JQ1 and the FLT3-TKI caused greater attenuation of c-MYC, BCL2, and CDK4/6. Simultaneously, cotreatment with JQ1 and the FLT3-TKI increased the levels of p21, BIM, and cleaved PARP, as well as mediated marked attenuation of p-STAT5, p-AKT, and p-ERK1/2 levels in AML BPCs. Conversely, cotreatment with JQ1 and FLT3-TKI was significantly less active against CD34(+) normal bone marrow progenitor cells. Knockdown of BRD4 by short hairpin RNA also sensitized AML cells to FLT3-TKI. JQ1 treatment induced apoptosis of mouse Ba/F3 cells ectopically expressing FLT3-ITD with or without FLT3-TKI-resistant mutations F691L and D835V. Compared with the parental human AML FLT3-ITD-expressing MOLM13, MOLM13-TKIR cells resistant to AC220 were markedly more sensitive to JQ1-induced apoptosis. Furthermore, cotreatment with JQ1 and the pan-histone deacetylase inhibitor (HDI) panobinostat synergistically induced apoptosis of FLT3-TKI-resistant MOLM13-TKIR and MV4-11-TKIR cells. Collectively, these findings support the rationale for determining the in vivo activity of combined therapy with BA and FLT3-TKI against human AML cells expressing FLT3-ITD or with BA and HDI against AML cells resistant to FLT3-TKI.

The tyrosine kinase activity of the Bcr/Abl oncogene is required for transformation of hematopoietic cells. The tyrosine kinase inhibitor STI571 (formerly called CGP57148B, Novartis Pharmaceuticals) inhibits BCR/ABL, TEL/ABL, and v-ABL kinase activity and inhibits growth and viability of cells transformed by any of these ABL oncogenes. Here we report the generation of 2 BCR/ABL-positive cell lines that have developed partial resistance to STI571. BCR/ABL-transformed Ba/F3 hematopoietic cells and Philadelphia-positive human K562 cells were cultured in gradually increasing concentrations of STI571 over a period of several months to generate resistant lines. Resistant Ba/F3.p210 cells were found to have an increase in Bcr/Abl messenger RNA, amplification of the Bcr/Abl transgene, and a greater than tenfold increase in the level of BCR/ABL protein. In contrast to Ba/F3.p210 cells, drug-resistant K562 cells did not undergo detectable amplification of the BCR/ABL gene, although they displayed a 2-fold to 3-fold increase in p210BCR/ABL protein. The addition of STI571 to both resistant Ba/F3. p210 and K562 cells resulted in a rapid reduction of tyrosine phosphorylation of cellular proteins, similar to that observed for nonresistant cells. However, the inhibition of kinase activity was transient and partial and was not accompanied by apoptosis. The results suggest that resistance to STI571 may be multifactorial. Increased expression of the target protein BCR/ABL was observed in both lines, and resulted from oncogene amplification in one line. However, altered drug metabolism, transport, or other related mechanisms may also contribute to drug resistance.

Erythropoietin (Epo) initiates its cellular response by binding to the Epo receptor, which triggers the activation of signal transducer and activator of transcription (Stat) 5 protein. Cell culture studies of erythroid progenitors have suggested that Epo functions as a survival factor by repressing apoptosis at least in part through Bcl-x(L), an anti-apoptotic protein of the Bcl-2 family. In this report, we examine whether Stat5 can induce transactivation of the bcl-x gene in response to Epo. Two Epo-responsive progenitor cell lines, HCD-57 and Bcl-2-transfected Ba/F3-Epo receptor (Ba/F3-EpoR-Bcl-2), were used in this study. After Epo stimulation, we observed a correlation between expression of bcl-x(L) and activation of Stat5 as assessed by the expression of oncostatin M, a direct target of Stat5, and the phosphorylation and nuclear translocation of Stat5. Moreover, a Stat binding element in the bcl-x promoter was found to be active in response to Epo, a finding that was further confirmed because mutagenesis of this sequence motif abrogated its promoter activity and overexpression of a dominant negative Stat5 protein blocked transactivation. When DNA-protein binding analyses were performed, we found that Stat5, not Stat1 or Stat3, was the protein bound to the bcl-x promoter in response to Epo. These data suggest that Epo-dependent activation of Stat5 is a transcriptional pathway that can be used by Epo-responsive progenitor cells to induce the expression of bcl-x(L) and consequently to inhibit apoptosis.

Betacellulin is a member of the epidermal growth factor (EGF) family. These soluble proteins are ligands for one or more of the four receptor tyrosine kinases encoded by the erbB gene family (erbB-1/epidermal growth factor receptor (EGFR), neu/erbB-2/HER2, erbB-3/HER3 and erbB-4/HER4). While evidence suggests that betacellulin is a ligand for the EGFR, the ability of betacellulin to regulate other erbB family receptors has not been analysed. Previously we engineered derivatives of the mouse Ba/F3 hematopoietic cell line to ectopically express erbB family receptors, singly and in pairwise combinations. We have stimulated this panel of cell lines with betacellulin and two other EGF family members, EGF itself and neuregulin-beta (NRG-beta). In the cell lines expressing a single erbB family receptor, betacellulin not only stimulated EGFR tyrosine phosphorylation, but it activated erbB-4 as well. Furthermore, in the double recombinant Ba/F3 derivatives, betacellulin stimulated a complex pattern of receptor phosphorylation distinct from the patterns activated by NRG-beta and EGF. Moreover, betacellulin stimulated a complex pattern of interleukin-3 independence in the Ba/F3 derivatives distinct from those activated by NRG-beta and EGF. These data identify a novel receptor for betacellulin and establish that different EGF family ligands activate distinct patterns of receptor phosphorylation and coupling to cellular signaling pathways.

Up to 30% of acute myelogenous leukemia (AML) patients harbor an activating internal tandem duplication (ITD) within the juxtamembrane domain of the FLT3 receptor, suggesting that it may be a target for kinase inhibitor therapy. For this purpose we have developed CT53518, a potent antagonist that inhibits FLT3, platelet-derived growth factor receptor (PDGFR), and c-Kit (IC(50) approximately 200 nM), while other tyrosine or serine/threonine kinases were not significantly inhibited. In Ba/F3 cells expressing different FLT3-ITD mutants, CT53518 inhibited IL-3-independent cell growth and FLT3-ITD autophosphorylation with an IC(50) of 10-100 nM. In human FLT3-ITD-positive AML cell lines, CT53518 induced apoptosis and inhibited FLT3-ITD phosphorylation, cellular proliferation, and signaling through the MAP kinase and PI3 kinase pathways. Therapeutic efficacy of CT53518 was demonstrated both in a nude mouse model and in a murine bone marrow transplant model of FLT3-ITD-induced disease.

Reciprocal crosses between Ixodes dammini Spielman, Clifford, Piesman & Corwin from Massachusetts and Ixodes scapularis Say from Georgia produced offspring through the F3 generation when the experiment was discontinued. Reciprocal I. dammini x Ixodes pacificus Cooley & Kohls (California) and I. scapularis x I. pacificus crosses produced F1 progeny; however, all progeny were sterile. Assortative mating experiments between I. dammini and I. scapularis indicated that males and females of both species mated with the opposite sex of heterospecific or conspecific ticks when there was a choice. Conventional discriminant analysis of morphometric measurements of ticks from Georgia, North Carolina, Maryland, Massachusetts, and two populations of F1 hybrids indicated that there were recognizable differences. However, size-free (sheared) discriminant analysis indicated that these differences were largely size-dependent, with much overlap of the four eastern and two hybrid populations but no overlap with I. pacificus from California. Analysis of chromosomes (morphology and C band) indicated no differences between the Georgia and Massachusetts populations but showed a difference between them and the California population of I. pacificus. Analysis of isozymes showed that the genetic identity value for the Georgia and Massachusetts populations was within the normal range for conspecific populations, whereas the California population indicated congeneric but not conspecific relatedness to the Georgia and Massachusetts populations. Life cycle data collected under similar laboratory conditions showed no differences in length of feeding and molting periods among Georgia, Massachusetts, and California populations. These data and results of the work of other authors on tick host preferences and vector competence indicate that I. dammini is not a valid species separate from I. scapularis. Because the name Ixodes scapularis Say, 1821, has priority over the name Ixodes dammini Spielman, Clifford, Piesman & Corwin, 1979, I. dammini is relegated to a junior subjective synonym of I. scapularis (based on Article 23 of the International Code of Zoological Nomenclature).

OBJECTIVE

Transient elastography (TE) is adequate for a diagnosis of cirrhosis, but its accuracy for milder stages of fibrosis is much less satisfactory. The objective of this study was to compare the performance and the discordance rate of acoustic radiation force impulse (ARFI) and TE with liver biopsy in a cohort of chronic hepatitis C (CHC) patients.

METHODS

One hundred thirty-nine consecutive patients with CHC were enrolled in two tertiary centers, and evaluated for histological (Metavir score) and biochemical features. All patients underwent TE and ARFI.

RESULTS

TE was unreliable in nine patients (6.5%), while in no cases (0%) were ARFI invalid measurements recorded (P=0.029). By area under receiver operating characteristic curve (AUROC), the best cutoff values for TE and ARFI for significant fibrosis (≥F2) were ≥6.5 kPa (AUROC: 0.78) and ≥1.3 m/s (AUROC: 0.86), respectively. For severe fibrosis (F3-F4), these cutoff values were 8.8 kPa (AUROC: 0.83) for TE and 1.7 m/s (AUROC: 0.94) for ARFI. For cirrhosis, TE had its best cutoff at ≥11 kPa (AUROC: 0.80) and ARFI at ≥2.0 m/s (AUROC: 0.89). By pairwise comparison of AUROC, ARFI was significantly more accurate than TE for a diagnosis of significant and severe fibrosis (P=0.024 and P=0.002, respectively), while this difference was only marginal for cirrhosis (P=0.09). By partial AUROC analysis, ARFI performance results significantly higher for all three stages of fibrosis. The average concordance rates of TE and ARFI vs. liver biopsy were 45.4 and 54.7%, respectively. By multivariate analysis, ARFI was not associated with alanine aminotransferase (ALT), body mass index, Metavir grade, and liver steatosis, while TE was significantly correlated with the ALT value (P=0.027).

CONCLUSIONS

In a cohort of patients with CHC, ARFI imaging was more accurate than TE for the non-invasive staging of both significant and severe classes of liver fibrosis.

The TEL/PDGF beta R fusion protein is the product of the t(5;12) translocation in patients with chronic myelomonocytic leukemia. The TEL/PDGF beta R is an unusual fusion of a putative transcription factor, TEL, to a receptor tyrosine kinase. The translocation fuses the amino terminus of TEL, containing the helix-loop-helix (HLH) domain, to the transmembrane and cytoplasmic domain of the PDGF beta R. We hypothesized that TEL/PDGF beta R self-association, mediated by the HLH domain of TEL, would lead to constitutive activation of the PDGF beta R tyrosine kinase domain and cellular transformation. Analysis of in vitro-translated TEL/ PDGF beta R confirmed that the protein self-associated and that self-association was abrogated by deletion of 51 aa within the TEL HLH domain. In vivo, TEL/PDGF beta R was detected as a 100-kDa protein that was constitutively phosphorylated on tyrosine and transformed the murine hematopoietic cell line Ba/F3 to interleukin 3 growth factor independence. Transformation of Ba/F3 cells required the HLH domain of TEL and the kinase activity of the PDGF beta R portion of the fusion protein. Immunoblotting demonstrated that TEL/PDGF beta R associated with multiple signaling molecules known to associate with the activated PDGF beta R, including phospholipase C gamma 1, SHP2, and phosphoinositol-3-kinase. TEL/PDGF beta R is a novel transforming protein that self-associates and activates PDGF beta R-dependent signaling pathways. Oligomerization of TEL/PDGF beta R that is dependent on the TEL HLH domain provides further evidence that the HLH domain, highly conserved among ETS family members, is a self-association motif.

OBJECTIVE

Beta-blockers are extensively used to prevent variceal bleeding in patients with large esophageal varices. It is not established if beta-blockers delay the growth of small varices.

METHODS

A total of 161 patients with cirrhosis and small esophageal varices (F1 according to the classification of Beppu et al.) without previous bleeding were enrolled. A total of 83 patients were randomized to nadolol (dose adjusted to decrease resting heart rate by 25%; mean dose given, 62 +/- 25 mg/day) and 78 to placebo. The principal end point was occurrence of large esophageal varices (F2 or F3 according to the classification of Beppu et al.). Endoscopic examination was performed after 12, 24, 36, 48, and 60 months of follow-up. Mean follow-up was 36 months.

RESULTS

The 2 groups were well matched for demographic and clinical characteristics. During the study period, 9 patients randomized to nadolol and 29 randomized to placebo had growth of esophageal varices. At the end of follow-up, the cumulative risk was 20% versus 51% (P < 0.001) (absolute risk difference, 31%; 95% confidence interval, 17%-45%). When possible confounding factors were taken into account, treatment was a significant factor predicting growth of varices (odds ratio, 4.0; 95% confidence interval, 1.95-8.4). The cumulative probability of variceal bleeding was also lower in patients randomized to nadolol (P = 0.02). Survival was not different (P = 0.33). Adverse effects resulting in withdrawal of drug occurred in 9 in the nadolol group and one in the placebo group (P = 0.01).

CONCLUSIONS

This study suggests that beta-blocker prophylaxis of variceal bleeding in patients with compensated cirrhosis should be started when small esophageal varices are present.