Specific increase in enzymatic activity of adenosine deaminase 1 in rheumatoid synovial fibroblasts

OBJECTIVE: Adenosine deaminase (ADA; EC 3.5.4.4) activity is elevated in the synovial fluid (SF) of patients with rheumatoid arthritis (RA). Since the antiinflammatory effect of methotrexate is reportedly associated with increased levels of extracellular adenosine, the present study was undertaken to clarify the role of 2 ADA isozymes, ADA1 and ADA2, in the pathogenesis of RA. METHODS: The activities of ADA1 and ADA2 were measured in SF from RA and osteoarthritis (OA) patients, in sera from RA patients, and in lysates prepared from mononuclear and polymorphonuclear cells from SF from RA patients, peripheral blood from RA patients, and fibroblast-like synoviocytes (FLS) from RA and OA patients. Also measured were the effects of proinflammatory cytokines on ADA1 activity and ADA messenger RNA (mRNA) expression in RA FLS, as determined using real-time polymerase chain reaction. The adenosine concentration in RA SF was measured by radioimmunoassay. RESULTS: The adenosine concentration in RA SF ranged from 0.027 microM to 0.508 microM (mean +/- SD 0.156 +/- 0.132 microM). At those concentrations, ADA1 would be expected to be functionally dominant due to its higher affinity for adenosine. ADA1 activity in RA SF (mean +/- SD 14.4 +/- 8.5 IU/liter) was significantly higher than that in OA SF (3.0 +/- 1.1 IU/liter) or RA sera (3.0 +/- 0.6 IU/liter); moreover, ADA1 activity in RA FLS lysate was the highest among the cell lysates tested. Proinflammatory cytokines did not affect ADA1 activity or ADA mRNA expression in RA FLS. CONCLUSION: Elevated ADA1 activity is an intrinsic characteristic of RA FLS, which likely contributes to the pathogenesis of RA by neutralizing the antirheumatic properties of endogenous adenosine.     

Pharmacokinetics of pegylated recombinant human megakaryocyte growth and development factor in healthy volunteers and patients with hematological disorders

OBJECTIVES: The purpose of this study is to examine the pharmacokinetics of pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) in healthy volunteers with normal hematopoiesis and patients with idiopathic thrombocytopenic purpura (ITP), acute myeloid leukemia (AML), myelodysplastic syndromes (MDS), and aplastic anemia (AA). METHODS: PEG-rHuMGDF was intravenously administered to healthy volunteers and patients with ITP, AML, MDS, and AA. The serum concentration of PEG-rHuMGDF was measured and the pharmacokinetics was investigated using non-linear mixed-effects modeling technique. RESULTS: The systemic clearance (CL) and volume of distribution at steady-state (Vss) consistently decreased in the healthy subjects, when the dose increased. In AML patients, CL and Vss decreased when the dose increased, but the change of CL was not statistically significant. In contrast, no significant dose dependency of these parameter estimates was observed in MDS patients. In AA patients there was no significant change in Vss but the CL of the higher dose groups was slightly smaller than that of the lower dose groups. Relatively smaller CL and Vss in ITP patients than those of healthy volunteers at the same dose were observed. CONCLUSIONS: This saturable pathway of CL may involve the receptor-mediated endocytosis and degradation by megakaryocyte lineage cells and platelets. The saturable distribution space can be also explained by the receptors on hematopoietic cells. The non-saturable distribution space corresponds to the value of plasma and interstitial fluid volume.     

Effects of a 24-week course of interferon-α therapy after curative treatment of hepatitis C virus-associated hepatocellular carcinoma

AIM: To assess whether a 24-wk course of interferon (IFN) could prevent hepatocellular carcinoma (HCC) recurrence and worsening of liver function in patients with hepatitis C virus (HCV)-infected patients after receiving curative treatment for primary HCC. METHODS: Outcomes in 42 patients with HCV infection treated with IFN-α, after curative treatment for primary HCC (IFN group), were compared with 42 matched curatively treated historical controls not given IFN (nonIFN group). RESULTS: Although the rate of initial recurrence did not differ significantly between IFN group and non-IFN group (0%, 44%, 61%, and 67% vs 4.8%, 53%, 81%, and 87% at 1, 3, 5, and 7 years, P = 0.153, respectively), IFN group showed a lower rate than the non-IFN group for second recurrence (0%, 10.4%, 28%, and 35% vs 0%, 30%, 59%, and 66% at 1, 3, 5 and 7 years, P = 0.022, respectively). Among the IFN group, patients with sustained virologic response (SVR) were less likely to have a second HCC recurrence than IFN patients without an SVR, or non-IFN patients. Multivariate analysis identified the lack of SVR as the only independent risk factor for a second recurrence, while SVR and Child-Pugh class A independently favored overall survival. CONCLUSION: Most intrahepatic recurrences of HCVrelated HCC occurred during persistent viral infection. Eradication of HCV is essential for the prevention of HCC recurrence and improvement of survival.     

Glycated albumin is a better indicator for glucose excursion than glycated hemoglobin in type 1 and type 2 diabetes

To determine the impact of blood glucose profile, involving fluctuation and excursion of blood glucose levels, on glycated proteins, we evaluated the association among the daily profile of blood glucose, and glycated albumin (GA) and HbA1c levels in patients with type 1 diabetes (n = 93) and type 2 diabetes (n = 75). GA levels were strongly correlated with HbA1c levels in type 1 (r = 0.85, P<0.0001) and type 2 diabetes (r = 0.61, P<0.0001), respectively. HbA1c levels were similar between patients with type 1 and type 2 diabetes, while GA levels were significantly higher in type 1 diabetes. Thus the ratio of GA levels to HbA1c levels was significantly higher in type 1 diabetes than that in type 2 diabetes (3.32 0.36 vs. 2.89 0.44, p<0.001). The degrees of GA levels and HbA1c levels correlated with maximum and mean blood glucose levels in patients with type 1 and type 2 diabetes. Stepwise multivariate analysis revealed that GA levels independently correlated with maximum blood glucose levels in type 1 diabetes (F = 43.34, P<0.001) and type 2 diabetes (F = 41.57, P<0.001). HbA1c levels also independently correlated with maximum blood glucose levels in type 1 diabetes (F = 34.78, P<0.001), as well as being correlated with mean blood glucose levels in type 2 diabetes (F = 11.28, P<0.001). In summary, GA could be a better marker for glycemic control than glycated hemoglobin in diabetic patients, especially for evaluating glycemic excursion, which is considered to be a major cause of diabetic angiopathy.     

Circulating level of large splice variants of tenascin-C is a marker of piecemeal necrosis activity in patients with chronic hepatitis C.

BACKGROUNDS: It has been reported that histological activity index and piecemeal necrosis are good factors to evaluate the prognosis in patients with chronic hepatitis C (CHC). Thus, there is a need for simple and noninvasive means to assess disease activity and piecemeal necrosis in patients with CHC. In this study, we measured the serum concentrations of large splice variants of tenascin-C (cTN-C) in patients with CHC, and examined their correlation with the degree of inflammatory activity and fibrosis as evaluated in liver biopsy specimens. METHODS: The serum levels of cTN-C in 150 patients with CHC and 50 healthy volunteers were measured by enzyme-linked immunosorbent. The histology of liver biopsy specimens was also evaluated following the Desmet's grading/staging system and the Ishak's classification. Liver specimens obtained by biopsy were also immunohistochemically evaluated with anti-human tenascin-C antibodies. RESULTS: Serum cTN-C concentrations were significantly higher in CHC patients than in healthy volunteers (P < 0.0001). The levels of cTN-C showed no significant difference among the fibrosis stages as assessed by the Desmet's grading/staging system and Ishak's classification scores. However, the concentration of cTN-C was significantly correlated with the grade of activity. According to the Ishak's classification, the concentration of cTN-C was increased in proportion to the degree of piecemeal necrosis. Specific immunostaining of cTN-C was observed in limited areas of piecemeal necrosis but not in fibrotic areas. CONCLUSION: The measurement of serum levels of cTN-C is a useful marker of the activity of CHC, in particular of the degree of piecemeal necrosis.     

An aggressive nasal lymphoma accompanied by high levels of soluble Fas ligand

Fas ligand (FasL), either in the membrane bound form or soluble form, has cytotoxic activity against Fas-expressing cells. We report a case of nasal lymphoma accompanied by liver damage and pancytopenia. The serum level of soluble FasL (sFasL) was very high on admission, but rapidly decreased to normal levels after chemotherapy for lymphoma. Liver damage and pancytopenia also improved with the decrease in serum sFasL. Since Fas is expressed on both hepatocytes and haemopoietic cells, these facts suggest that FasL was expressed on lymphoma cells and directly associated with pathogenesis of liver damage and pancytopenia through its cytotoxic activity.     

Immunofluorescence staining of renal biopsy samples in patients with diabetic nephropathy in non-insulin-dependent diabetes mellitus using monoclonal antibody to reduced glycated lysine

This is the first report on immunofluorescence staining of renal biopsy samples in human diabetic nephropathy (DN) using monoclonal antibodies to reduced glycated lysine. In order to detect the localization of glycated lysine in the mesangial matrix and/or the glomerular basement membrane (GBM), we examined immunofluorescence staining using antibodies against reduced glycated lysine in the glomeruli of 16 patients with DN and ten age-matched patients with diffuse mesangial proliferative glomerulonephritis without IgA deposition (DPGN) as controls. In the early stage of DN, immunofluorescence microscopy revealed the presence of intense staining for reduced glycated lysine in the GBM as well as in part of the tubular basement membrane, but not in the mesangial area. In contrast, immunofluorescence microscopy revealed less staining for glycated lysine in the GBM in the advanced stage of DN, and no reaction with any part of the renal tissue in patients with DPGN. It was concluded that detection of reduced glycated lysine in GBM in the early stage of DN might be associated with the initial pathogenesis of this disease.