PBC-AIH overlap syndrome with concomitant ITP and Hashimoto’s disease with positivity for anti-centromere antibody

We report a case of primary biliary cirrhosis (PBC)-autoimmune hepatitis (AIH) overlap syndrome with concurrent idiopathic thrombocytopenic purpura (ITP) and Hashimotos disease with positivity for anticentromere antibody. The patient was a 64-year-old woman with symptoms of jaundice and general fatigue. About 30 years earlier, she had been diagnosed as having ITP and had undergone splenectomy. As part of her present history, she had exhibited liver dysfunction in 1995, during the follow-up of Hashimotos disease, and a liver biopsy led to the diagnosis of PBC. In March 2000, she was admitted to hospital because of general fatigue and jaundice. Blood tests revealed: total protein (TP), 6.6g/dl; -globulin (glb), 35.9%; total bilirubin (T-bil), 9.41mg/dl; direct bilirubin (D-bil), 7.52mg/dl; aspartate aminotransferase (AST), 957U/l; alanine aminotransferase (ALT), 651U/l; alkaline phosphatase (ALP), 595U/l; -guanosine triphosphate (GTP), 129U/l; IgG, 2620mg/dl; IgM, 223mg/dl; hepatitis B surface antigen (HBsAg), negative; anti-hepatitis C virus (HCV), negative; antinuclear antibody, positive; antimitchondrial antibody (AMA), negative (by the immunofluorescence [IF] method); and anti-pyruvate dehydrogenase complex (PDC)-E2 antibody, positive (by Western blotting). Anticentromere antibody (ACA), which is an alternative diagnostic marker for PBC, was detected in this patient. Prednisolone was administered after admission and liver function test results improved markedly. The liver biopsy in 1995 had revealed infiltration of lymphocytes and plasma cells in the portal areas with fibrous expansion and periportal necrosis. Destructive cholangitis was observed, as well as scattered epitheloid cell granulomas in some portal areas. Liver biopsy after the steroid treatment revealed alleviated necrotic inflammatory responses of hepatocytes, while the destructive cholangitis persisted. This is a very rare case of PBC-AIH overlap syndrome accompanied by ITP and Hashimotos disease which provides a possible insight into the mechanisms and interplay of autoimmune diseases.     

Efficacy and safety of entecavir in lamivudine-refractory patients with chronic hepatitis B: randomized controlled trial in Japanese patients

Background and Aim:  Entecavir is a potent inhibitor of both wild-type and lamivudine-resistant hepatitis B virus (HBV) with proven clinical efficacy. We conducted a randomized, double-blind, multicenter study in Japan (ETV-052) evaluating the efficacy and safety of two doses of entecavir in adult patients with lamivudine-refractory chronic hepatitis B infection.
Methods:  Eighty-four patients with chronic hepatitis B who were refractory to lamivudine therapy were switched from lamivudine to daily oral doses of 0.5 mg entecavir (41 patients) or 1 mg entecavir (43 patients) for 52 weeks.
Results:  The proportions of patients achieving the primary end-point (≥2 log₁₀ reduction in HBV-DNA from baseline by polymerase chain reaction assay or undetectable HBV-DNA levels [<400 copies/mL] at week 48) were 90% and 93% for entecavir 0.5 mg and 1 mg, respectively, with 33% of patients in each dosing group achieving <400 copies/mL. The mean reduction in HBV-DNA from baseline was 3.58 and 3.75 log₁₀ copies/mL for entecavir 0.5 mg and 1 mg, respectively. High proportions of patients achieved alanine aminotransferase normalization at week 48 (0.5 mg 86%, 1 mg 78%). Histological improvement was observed in most patients (0.5 mg 52%, 1 mg 60%). Virological breakthrough (increase in HBV-DNA of ≥1 log₁₀ copies/mL from nadir) was observed in one patient but was not associated with selection of entecavir-associated resistance substitutions. Entecavir was well tolerated, with no patients discontinuing study drug due to adverse events.
Conclusions:  These findings indicate that entecavir is safe and effective for the treatment of Japanese adults with lamivudine-refractory chronic hepatitis B.     

Oncogenic and RASopathy-associated K-RAS mutations relieve membrane-dependent occlusion of the effector-binding site

K-RAS4B (Kirsten rat sarcoma viral oncogene homolog 4B) is a prenylated, membrane-associated GTPase protein that is a critical switch for the propagation of growth factor signaling pathways to diverse effector proteins, including rapidly accelerated fibrosarcoma (RAF) kinases and RAS-related protein guanine nucleotide dissociation stimulator (RALGDS) proteins. Gain-of-function KRAS mutations occur frequently in human cancers and predict poor clinical outcome, whereas germ-line mutations are associated with developmental syndromes. However, it is not known how these mutations affect K-RAS association with biological membranes or whether this impacts signal transduction. Here, we used solution NMR studies of K-RAS4B tethered to nanodiscs to investigate lipid bilayer-anchored K-RAS4B and its interactions with effector protein RAS-binding domains (RBDs). Unexpectedly, we found that the effector-binding region of activated K-RAS4B is occluded by interaction with the membrane in one of the NMR-observable, and thus highly populated, conformational states. Binding of the RAF isoform ARAF and RALGDS RBDs induced marked reorientation of K-RAS4B from the occluded state to RBD-specific effector-bound states. Importantly, we found that two Noonan syndrome-associated mutations, K5N and D153V, which do not affect the GTPase cycle, relieve the occluded orientation by directly altering the electrostatics of two membrane interaction surfaces. Similarly, the most frequent KRAS oncogenic mutation G12D also drives K-RAS4B toward an exposed configuration. Further, the D153V and G12D mutations increase the rate of association of ARAF-RBD with lipid bilayer-tethered K-RAS4B. We revealed a mechanism of K-RAS4B autoinhibition by membrane sequestration of its effector-binding site, which can be disrupted by disease-associated mutations. Stabilizing the autoinhibitory interactions between K-RAS4B and the membrane could be an attractive target for anticancer drug discovery.The K-RAS4B (Kirsten rat sarcoma viral oncogene homolog 4B) protein product of the KRAS gene undergoes posttranslational farnesylation and C-terminal processing, which, in conjunction with a poly-basic hypervariable region (HVR), targets K-RAS4B to anionic lipid rafts on the intracellular side of the plasma membrane (Fig. 1A) (1). This localization is essential for K-RAS4B function and enhances signaling fidelity (2). Although the significance of membrane tethering of K-RAS4B is well appreciated, a high-resolution map of how K-RAS4B interacts with the membrane is lacking. Because membrane-anchored RAS presents a major challenge to crystallization, current structural insights into the behavior of membrane-anchored RAS have come from a variety of lower-resolution techniques including in vivo FRET-based studies (3), fluorescence and infrared spectroscopic studies (4–6), and in silico models (3). These pioneering studies suggested that the K-RAS4B GTPase domain adopts certain preferred orientations on the anionic membrane and that these orientations could be influenced by the bound nucleotide. Here we present high-resolution NMR-derived models of the dynamic interactions between K-RAS4B and the lipid bilayer and how they can be impacted by disease-associated mutations or interactions with effector proteins.Open in a separate windowFig. 1.K-RAS4B signaling at the plasma membrane and the nanodisc lipid bilayer model for NMR studies. (A) Schematic illustration of K-RAS4B signaling on plasma membrane. (Inset) Schematic of a K-RAS4B:nanodisc complex. (B) Distribution of eleven isoleucine Cδ throughout the K-RAS4B GTPase-domain. (Right) ¹H-¹³C HMQC spectra of nanodisc-conjugated K-RAS4B in the GDP- (Upper) and GMPPNP- (Lower) bound forms.     

Significantly increased risk of cancer in diabetes mellitus patients: A meta‐analysis of epidemiological evidence in Asians and non‐Asians

Aims/Introduction: Emerging evidence from observational studies suggests that diabetes mellitus affects the cancer risk. However, whether there are differences in the magnitude of the influence of diabetes among ethnic groups is unknown. Materials and Methods: We searched MEDLINE and the Cochrane Library for pertinent articles that had been published as of 4 April 2011, and included them in a meta‐analysis of the risk of all‐cancer mortality and incidence in diabetic subjects. Results: A total of 33 studies were included in the meta‐analysis, and they provided 156,132 diabetic subjects for the mortality analysis and 993,884 for the incidence analysis. Cancer mortality was approximately 3%, and cancer incidence was approximately 8%. The pooled adjusted risk ratio (RR) of all‐cancer mortality was significantly higher than for non‐diabetic people (RR 1.32 [CI 1.20–1.45] for Asians; RR 1.16 [CI 1.01–1.34] for non‐Asians). Diabetes was also associated with an increased RR of incidence across all cancer types (RR 1.23 [CI 1.09–1.39] for Asians; RR 1.15 [CI 0.94–1.43] for non‐Asians). The RR of incident cancer for Asian men was significantly higher than for non‐Asian men (P = 0.021). Conclusions: Diabetes is associated with a higher risk for incident cancer in Asian men than in non‐Asian men. In light of the exploding global epidemic of diabetes, particularly in Asia, a modest increase in the cancer risk will translate into a substantial socioeconomic burden. Our current findings underscore the need for clinical attention and better‐designed studies of the complex interactions between diabetes and cancer. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2011.00183.x, 2012)     

Twenty-four weeks of interferon alpha-2b in combination with ribavirin for Japanese hepatitis C patients: sufficient treatment period for patients with genotype 2 but not for patients with genotype 1.

BACKGROUND: Hepatitis C virus (HCV) RNA titer and HCV genotype are two major determinants of the outcome of interferon (IFN) monotherapy. To clarify the usefulness of combination therapy with IFN and ribavirin in Japanese hepatitis C patients, we treated patients with a relatively high dose of IFN in combination with ribavirin for 24 weeks and examined the effects in relation to the viral parameters. METHODS: Two hundred and ninety-five patients were enrolled in the study. The patients received either 6 or 10 million units (MU) of interferon alpha-2b every day for 2 weeks and then three times a week for 22 weeks with a daily dose of either 600 or 800 mg of ribavirin. The treatment response and safety of this treatment were examined. RESULTS: The sustained virologic response (SVR) rates were 26.8% in genotype 1 and 76.5% in genotype 2 (P < 0.001), and 36.1% with the 6 MU group and 45.8% with the 10 MU group (P = 0.09). Multivariate analysis indicated that SVR was associated with genotype 2, HCV RNA <500 kilointernational unit/ml (kIU/ml), and HCV RNA undetectability at week 8 of treatment. CONCLUSION: Our current study showed that a 24-week course of IFN plus ribavirin combination therapy was effective with respect to virologic response in Japanese hepatitis C patients, particularly in patients with HCV genotype 2.     

Muscle excursion does not correlate with increased serial sarcomere number after muscle adaptation to stretched tendon transfer

Chronic skeletal muscle stretch typically increases serial muscle fiber sarcomere number. Since serial sarcomere number correlates with functional excursion in normal muscle, observed changes in sarcomere number are often extrapolated to their new assumed function. However, this has not been well demonstrated experimentally. Thus, we measured the functional properties of muscles stretched due to tendon transfer surgery. Muscle active and passive length–tension curves were measured 1 week and 4 weeks after surgery, and then each muscle was further examined to determine structural adaptation as well as single fiber and fiber bundle passive mechanical properties. We found a disconnect between the functional and structural muscle properties. Specifically, muscle excursion was significantly lower in the transferred muscle compared to controls, even though serial sarcomere number had increased. Furthermore, maximum tetanic tension was significantly reduced, though the two groups had similar physiological cross sectional areas. Passive tension increased in the transferred muscle, which was deemed to be due to proliferation of extracellular matrix. These data are the first to report that muscle morphological adaptation after chronic stretch does not accurately predict the muscle's functional properties. These data have significant implications for examining muscle physiological properties under surgical interventions. © 2012 Orthopaedic Research Society. This article is a US Government work and, as such, is in the public domain in the United States of America. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1774–1780, 2012