Etiological factors in primary hepatic B-cell lymphoma

Sixty-four cases of malignant lymphoma involving the liver were examined. Of these, 20 cases were histologically confirmed to be primary hepatic B-cell lymphoma. Twelve of these 20 cases were diffuse large B-cell lymphoma (DLBCL) and eight cases were mucosa-associated lymphoid tissue (MALT) lymphoma. Of the 12 cases of DLBCL, six were immunohistologically positive for CD10 and/or Bcl6 (indicating a germinal center phenotype), six were positive for Bcl2, and five were positive for CD25. Eight of the 12 DLBCL cases (66.7%) and two of the eight MALT lymphoma cases (25%) had serum anti-hepatitis C virus (HCV) antibodies and HCV RNA. The incidence of HCV infection was significantly higher in the hepatic DLBCL cases than in systemic intravascular large B-cell cases with liver involvement (one of 11 cases, 9.1%) and T/NK-cell lymphoma cases (one of 19 cases, 5.3%) (p?相似文献   

Processing of neuregulin-1 by neuropsin regulates GABAergic neuron to control neural plasticity of the mouse hippocampus

Protease-mediated signaling is an important modulator of the nervous system. However, identifying the specific signaling substrates of such proteases is limited by the rapidity with which intermediate substrate forms are cleaved and released. Here, a screening method to detect noncleaved enzyme-bound forms was developed and used to identify a novel neuropsin/neuregulin-1 (NRG-1) proteolytic signaling system, which is specifically localized in the microdomain of synaptic cleft, in the mouse hippocampus. The extracellular protease, neuropsin, cleaved mature NRG-1 (comprising the extracellular domain of the NRG-1) at three newly identified sites to remove the heparin-binding domain of NRG-1. This released the ligand moiety from the matrix-glycosaminoglycan pool and enabled it to trigger the phosphorylation of NRG-1 receptor, p185 (ErbB4). Proteolysis of mature NRG-1 by neuropsin led to colocalization of the processed NRG-1 with ErbB4 in parvalbumin-positive hippocampal interneurons and consequent phosphorylation of tyrosine residues of proteins in the cells. Moreover, neuropsin knock-out mice exhibited impairments in Schaffer collateral early phase long-term potentiation, and application of the recombinant NRG-1 lacking heparin-binding activity reversed the effects through the activation of ErbB4 and GABA(A) receptors. Thus, ErbB4 signaling induced by neuropsin-dependent processing of NRG-1 contributes to the modulation of synaptic plasticity via regulation of GABAergic transmission. This signaling system may be involved in human cognition and mental disorders, such as schizophrenia and bipolar disorder, by its dysfunction.     

Identification of amino acids in Marburg virus VP40 that are important for virus-like particle budding

The matrix protein VP40 of Marburg virus promotes the formation and release of virus-like particles (VLPs). Marburg virus VP40 interacts with cellular Tsg101 via its L domain motif; however, mutation of this motif does not affect VLP budding or the accumulation of VP40 in multivesicular bodies (MVBs), which are platforms for virus particle formation. To identify regions of Marburg virus VP40 that are important for VLP budding, we examined deletion mutants and alanine-scanning mutants at the N- and C-terminus of VP40 for their involvement in VLP budding. VLPs were not detected in the presence of alanine-replacement mutants at Ile39 and Thr40, and the level of VLP budding for the alanine mutant at Asn297 was decreased. Moreover, these mutants did not accumulate in MVBs. Our results suggest the involvement of a novel host factor(s) in VLP budding and VP40 transport to MVBs.     

Ezetimibe decreases serum levels of asymmetric dimethylarginine (ADMA) and ameliorates renal injury in non-diabetic chronic kidney disease patients in a cholesterol-independent manner

Synthesis of nitric oxide (NO) can be blocked by inhibition of nitric oxide synthase (NOS) active site with guanidino-substituted analogues of l-arginine such as asymmetric dimethylarginine (ADMA). There is growing evidence that elevation of serum ADMA levels play a role in the progression of atherosclerosis and chronic kidney disease (CKD) in high-risk patients. Further, dyslipidemia contributes to cardiorenal disease as well. However, effects of ezetimibe, a specific inhibitor of cholesterol absorption and widely used drug for the treatment of dyslipidemia, on serum ADMA levels and renal injury remain unknown. In this study, we examined whether ezetimibe treatment decreased serum levels of ADMA, proteinuria and urinary excretion levels of 8-hydroxydeoxyguanosine (8-OHdG) and l-fatty acid binding protein (l-FABP), markers of oxidative stress and tubular injury, respectively and investigated their relationships in 10 non-diabetic CKD patients with dyslipidemia. Ezetimibe treatment (10 mg/day) for 6 months significantly decreased circulating levels of LDL-cholesterol, triglycerides and ADMA, while it increased HDL-cholesterol levels. Further, ezetimibe treatment significantly reduced urinary excretion levels of protein, l-FABP and 8-OHdG. In univariate analyses, serum ADMA levels were correlated with urinary protein, l-FABP and 8-OHdG levels. In multiple stepwise regression analysis, proteinuria was independently correlated with ADMA. Our present study demonstrated for the first time that ezetimibe decreased serum ADMA levels and improved renal injury in non-diabetic CKD patients with dyslipidemia in a cholesterol-independent manner. Ezetimibe may have pleiotropic actions, that is, ADMA-lowering and anti-oxidative effects, that could contribute to renoprotective properties of this lipid-lowering agent.     

Mucins in human neoplasms: clinical pathology, gene expression and diagnostic application

Mucins are high molecular weight glycoproteins that play important roles in carcinogenesis and tumor invasion. Our immunohistochemical studies demonstrated that MUC1 or MUC4 expression is related to the aggressive behavior and poor outcome of human neoplasms. MUC2 is expressed in indolent pancreatobiliary neoplasms, but these tumors sometimes show invasive growth with MUC1 expression in invasive areas. MUC5AC shows de novo high expression in many types of precancerous lesions of pancreatobiliary cancers and is an effective marker for early detection of the neoplasms. The combination of MUC1, MUC2, MUC4 and MUC5AC expression may be useful for early detection and evaluation of the potential for malignancy of pancreatobiliary neoplasms. Regarding the mechanism of mucin expression, we have recently reported that expression of the mucin genes is regulated epigenetically in cancer cell lines, using quantitative MassARRAY analysis, methylation-specific polymerase chain reaction analysis and chromatin immunoprecipitation analysis, with confirmation by the treatment with 5-aza-2'-deoxycytidine and trichostatin A. We have also developed a monoclonal antibody against the MUC1 cytoplasmic tail domain, which has many biological roles. Based on all of the above findings, we suggest that translational research into mucin gene expression mechanisms, including epigenetics, may provide new tools for early and accurate detection of human neoplasms.     

Asymmetric dimethylarginine may be a missing link between cardiovascular disease and chronic kidney disease

Decreased nitric oxide (NO) production and/or impaired NO bioavailability may occur in patients with chronic kidney disease (CKD), and could contribute to the elevation of blood pressure, cardiovascular disease (CVD) and the progression of renal injury in these patients. However, the underlying molecular mechanisms for reduced NO action in patients with CKD remains to be elucidated. Asymmetric dimethylarginine (ADMA) is a naturally occurring L-arginine analogue found in plasma and various types of tissues, acting as an endogenous NO synthase inhibitor in vivo. Further, plasma level of ADMA is elevated in patients with CKD and found to be a strong biomarker or predictor for future cardiovascular events. In addition, plasma level of ADMA could predict the progression of renal injury in these patients as well. These findings suggest that elevation of ADMA may be a missing link between CVD and CKD. In this review, we discuss the molecular mechanisms for the elevation of ADMA and its pathophysiological role for CVD in high-risk patients, especially focusing on patients with CKD.     

Asymmetric dimethylarginine (ADMA) is a novel emerging risk factor for cardiovascular disease and the development of renal injury in chronic kidney disease

Endothelial dysfunction due to the reduced bioavailability of nitric oxide (NO) is involved in the course of atherosclerotic cardiovascular disease as well as chronic kidney disease (CKD). NO is synthesized from L-arginine via the action of NO synthase, which is blocked by endogenous L-arginine analogues such as asymmetric dimethylarginine (ADMA). ADMA is a naturally occurring amino acid found in plasma and various types of tissues. The plasma level of ADMA is reported to be associated with cardiovascular risk factors such as hypertension, diabetes, hyperlipidemia, and CKD, and is a strong predictor for cardiovascular disease and the progression of CKD. In this review, we discuss the biology of ADMA, the molecular mechanisms of the elevation of ADMA levels in CKD, and the pathological role of ADMA in patients with CKD.