Liver stiffness measurement using acoustic radiation force impulse elastography in hepatitis C virus-infected patients with a sustained virological response.

BACKGROUND: Acoustic radiation force impulse (ARFI) elastography is a non-invasive method for measuring liver stiffness. However, there are no reports evaluating the value of ARFI elastography for liver fibrosis in chronic hepatitis C patients with a sustained virological response (SVR). AIM: To investigate the diagnostic performance of ARFI elastography for the assessment of liver fibrosis in hepatitis C virus (HCV) infected patients with an SVR. METHODS: In this prospective study, we enrolled 336 patients: 121 HCV patients with an SVR (44.6% women) and 215 patients with HCV (47.9% women). ARFI elastography measurements of all patients were performed on the same day of liver biopsy. RESULTS: The diagnostic accuracies, expressed as areas under the receiver operating characteristic curves for ARFI elastography, in HCV patients with an SVR and those in patients with HCV were 0.818 and 0.875 for the diagnosis of significant fibrosis (≥F2), 0.909 and 0.888 for the diagnosis of severe fibrosis (≥F3), and 0.981 and 0.890 for the diagnosis of liver cirrhosis (F4), respectively. The optimum cut-off values for ARFI elastography were 1.26 m/s for ≥F2, 1.31 m/s for ≥F3 and 1.49 m/s for F4 in HCV patients with an SVR. The liver stiffness values were lower in patients with SVR compared with those in patients with HCV at the same stage of fibrosis. The liver stiffness values were affected by the necroinflammatory activity and the time after SVR. CONCLUSION: Acoustic radiation force impulse elastography is an acceptable method for predicting the severity of fibrosis in patients with hepatitis C virus and a sustained viral response.

Comparison of 5-fluorouracil and 5-fluoro-2'-deoxyuridine as an effector in radiation-activated prodrugs.

The purpose of this study was to clarify whether 5-fluoro-2'-deoxyuridine (FdUrd) is superior to 5-fluorouracil (5-FU) as an effector in the radiation-activated prodrugs which we have been developing. The in vitro cytotoxicity of 5-FU and FdUrd was compared in two murine tumor and four human pancreatic cancer cell lines using a colony assay and in vivo efficacy was compared with SCCVII tumor using a growth delay time assay. FdUrd was slightly more hydrophilic than 5-FU. In vitro, FdUrd was more efficient than 5-FU in two lines, whereas 5-FU was more efficient in two lines and the two drugs were almost equal in efficacy in the remaining two. The concentration to reduce tumor cell survival to 50% after 24-h drug exposure was 5-32 microM for both 5-FU and FdUrd in murine lines, while it was 30-210 microM in human pancreatic cancer cell lines. The difference in relative efficacy of the two drugs among these cell lines could not be attributed to the rate of intracellular uptake of the compounds. FdUrd was less toxic than 5-FU in C3H/He mice, and FdUrd was less efficient than 5-FU in SCCVII tumors in vivo. These results suggest that FdUrd is not necessarily more potent than 5-FU, and development of the FdUrd prodrugs may not necessarily turn out to be fruitful.

Relationship between vitamin D receptor gene polymorphism and periodontitis.

UNLABELLED: Recent studies have shown that vitamin D receptor (VDR) gene polymorphism had regulatory effects on bone mineral density (BMD) and bone turnover. The VDR gene has also been indicated as a candidate gene for the susceptibility of osteoporosis. However, it is unclear whether VDR genotypes could be associated with alveolar bone loss of patients with periodontitis, or whether vitamin D receptor gene could be a candidate gene for susceptibility to periodontitis. The purpose of this study was to answer these two questions. METHODS: Twenty-four cases of adult periodontitis (AP), 37 cases of early onset periodontitis (EOP) and 39 healthy controls were recruited for the study. Individual samples of venous blood and DNA were obtained from each subject. Genotypes of the TaqI VDR gene were determined by PCR and TaqI restriction endonuclease digestion. RESULTS: One out of 24 AP patients, nine out of 37 EOP patients and two out of 39 healthy controls were detected with Tt genotype, while the rest had the TT genotype. The detected frequency of Tt genotype was significantly higher in EOP patients (24.3%) than in AP patients (4.2%) and healthy controls (5.1%). The frequency of t allele was also significantly higher in EOP patients. There was no statistical difference in the distribution of TaqI VDR genotypes between AP patients and healthy controls. The study suggests that Tt genotype might be a risk indicator for the susceptibility to EOP. Carriage of the allele (t) of the TaqI VDR gene may increase the risk of developing EOP.

Modulation of coordination chemistry in copper(I) complexes supported by Bis[2-(2-pyridyl)ethyl]amine-based tridentate ligands.

Structure and physicochemical properties of copper(I) complexes of the tridentate ligands L(2) (N,N-bis[2-(6-methylpyridin-2-yl)ethyl]phenethylamine) and L(3) (N,N-bis[2-(2-pyridyl)ethyl]-beta-methylphenethylamine) have been examined to obtain deeper insights into modulation of the coordination chemistry of copper(I) complexes. [Cu(I)(L(2))(CH(3)CN)](ClO(4)) (2.CH(3)CN) has a distorted tetrahedral geometry, which consists of three nitrogen atoms of the ligand and one nitrogen atom of the bound CH(3)CN. Steric repulsion between the 6-methyl group on the pyridine nucleus of L(2) and the metal ion of the complex prevents the cuprous complex from adaptation to a three-coordinate geometry which must have a shorter Cu-N(pyridine) distance ( approximately 1.88 A). Thus, the four-coordinate copper(I) complex (2.CH(3)CN) with a longer Cu-N bond (1.98 approximately 2.13 A) becomes favorable, resulting in rather strong binding of CH(3)CN to the metal ion. In [Cu(I)(L(3))](ClO(4)) (3), there is a Cu(I)-pi interaction between the cuprous ion and the phenyl group of the ligand sidearm. Such a copper(I)-arene interaction is essentially weak, but is significantly stabilized in complex 3. The methyl group at the benzylic position of L(3)() reduces the degree of freedom of sidearm rotation to make the phenyl group stick on the cuprous ion. Thus, the reactivity of the copper(I) complexes of L(2) and L(3) toward dioxygen is significantly diminished, showing sharp contrast to the high reactivity of the copper(I) complex supported by a similar tridentate ligand L(1) (N,N-bis[2-(2-pyridiyl)ethyl]phenethylamine).

Hyperglycemia in diabetic rats reduces the glutathione content in the aortic tissue.

The glutathione redox cycle plays a major role in scavenging hydrogen peroxide (H2O2) under physiological conditions. Recently, we demonstrated that a high glucose concentration in the culture medium reduced the level of H2O2 scavenging activity of human vascular smooth muscle cells (hVSMCs). We also showed that a high glucose concentration reduced the intracellular glutathione (GSH) content and the rate of uptake of cystine, which itself is a rate-limiting factor that maintains the GSH level (FEBS Lett.421: 19-22,1998). In the present study, we investigated whether the hyperglycemic condition in diabetic rats impairs the glutathione content in the aortic tissue in vivo. Wistar rats were divided into the following three groups: streptozotocin-induced diabetic rats (STZ-D, n=7), insulin-treated STZ-D rats (I-STZ-D, n=8), and non-diabetic controls (C, n=7). Fourteen days after streptozotocin injection, the aortic tissue was extracted and the GSH content in the aortic tissue was measured. Furthermore, the relationship between the GSH content in the aortic tissue and blood glucose level in Otsuka Long-Evans Tokushima Fatty (OLETF) rats aged 30 weeks, which developed diabetes spontaneously, was investigated. The GSH content in the aortic tissue of the STZ-D group (0.99+/-0.14 nmol/mg protein) was significantly lower than that of the control group (1.68+/-0.15 nmol/mg protein). Insulin treatment to the diabetic rats restored the GSH content in the aortic tissue (I-STZ-D group; 1.45+/-0.11 nmol/mg protein). Among the 22 Wistar rats, the GSH content in the aortic tissue was negatively correlated with the blood glucose level (r=-0.69, p<0.01, n=22). Among the OLETF rats, a similar negative correlation between the GSH content in the aortic tissue and blood glucose level was seen (r=-0.64, p<0.05, n=10). We demonstrated in vivo that the hyperglycemic condition in STZ-induced diabetic Wistar rats and OLETF rats reduced the GSH content in aortic tissue. This suggested reduced glutathione redox cycle function of aorta.

Experimental and modeling studies on sorption and diffusion of radium in bentonite.

The sorption and desorption behavior of radium on bentonite and purified smectite was investigated as a function of pH, ionic strength and liquid to solid ratio by batch experiments. The distribution coefficients (Kd) were in the range of 10(2) to > 10(4) ml g-1 and depended on ionic strength and pH. Most of sorbed Ra was desorbed by 1 M KCl. The results for purified smectite indicated that Ra sorption is dominated by ion exchange at layer sites of smectite, and surface complexation at edge sites may increase Ra sorption at higher pH region. Reaction parameters between Ra and smectite were determined based on an interaction model between smectite and groundwater. The reaction parameters were then used to explain the results of bentonite by considering dissolution and precipitation of minerals and soluble impurities. The dependencies of experimental Kd values on pH, ionic strength and liquid to solid ratio were qualitatively explained by the model. The modeling result for bentonite indicated that sorption of Ra on bentonite is dominated by ion exchange with smectite. The observed pH dependency was caused by changes of Ca concentration arising from dissolution and precipitation of calcite. Diffusion behavior of Ra in bentonite was also investigated as a function of dry density and ionic strength. The apparent diffusion coefficients (Da) obtained in compacted bentonite were in the range of 1.1 x 10(-11) to 2.2 x 10(-12) m2 s-1 and decreased with increasing in dry density and ionic strength. The Kd values obtained by measured effective diffusion coefficient (De) and modeled De were consistent with those by the sorption model in a deviation within one order of magnitude.

Heme-Cu complexes as oxygen-activating functional models for the active site of cytochrome c oxidase.

Tri(2-pyridylmethyl)amineCu complex-linked iron meso-tetraphenylporphyine derivatives were prepared to model the active site of cytochrome c oxidase. Exposure to oxygen converted the reduced forms of the complexes to the corresponding stable mu-peroxo species in spite of the presence of three coordination sites, two on the heme and one on the Cu. The oxy forms were characterized spectroscopically. Kinetic analyses of the oxygenation reactions of the reduced forms suggests that preferential O2 binding occurs at the Cu site over the heme. This mechanism is also supported by examination of the redox potentials of the two metal ions. Since the peroxy complexes of the models exhibit a structure similar to that of the previously reported fully-oxidized form, the relevance of the model chemistry to the enzyme reaction is discussed.

Association of vitamin D receptor gene polymorphism with periodontal diseases in Japanese and Chinese.

We examined whether polymorphisms in the vitamin D receptor (VDR) gene are associated with the incidence of adult periodontitis (AP) and early-onset periodontitis (EOP) in case-controlled studies of Japanese and Chinese subjects. Restriction fragment length polymorphisms in the VDR gene detected by digestion with Taq I were found to be significantly associated with the occurrence of AP or EOP, suggesting that the VDR genotype a risk factor for periodontitis.

Nitric oxide decreases insulin resistance induced by high-fructose feeding.

The effect of nitric oxide (NO) on insulin resistance was studied in high-fructose-fed rats. A sequential hyperinsulinemic euglycemic clamp procedure was employed (insulin infusion rates: 3 and 30 mU/kg BW/min) in 12 high-fructose-fed rats and 12 chow-fed rats while awake. Half of the high-fructose-fed and the chow-fed rats, respectively, were continuously given sodium nitroprusside (SNP, 3 ng/kg BW/min) during the clamp study. Blood glucose was clamped at the fasting level in each rat. Plasma insulin levels during the 3 and 30 mU/kg BW/min insulin infusions were 30 and 400 microU/ml, respectively. Metabolic clearance rate of glucose (MCR) was regarded as an index of whole body insulin action. At both 3 and 30 mU/kg BW/min insulin infusions, high-fructose feeding showed a significant decrease in MCR compared with the chow-fed rats. However, decreased MCRs were stimulated by SNP administration and reached similar levels as the chow-fed rats. SNP infusion did not influence MCRs in the chow-fed rats. Therefore it could be concluded that NO can improve insulin resistance induced by high-fructose feeding.

Effect of vitamin E on the degradation of hydrogen peroxide in cultured human umbilical vein endothelial cells.

Vitamin E reacts with radicals such as lipid peroxyl radical (LOO*) and singlet oxygen ((1)O2), and plays a role in inhibiting lipid peroxidation in cell membranes and preventing the oxidation of low-density lipoproteins (LDL). However, only a few studies have investigated the effect of vitamin E on the degradation of hydrogen peroxide (H2O2). Therefore, we examined the effect of vitamin E on glutathione redox cycle-dependent H2O2 degradation activity in human umbilical vein endothelial cells (HUVEC). Confluent HUVEC were cultured for seven days in media containing various concentrations of vitamin E (alpha-tocopherol). The level of glutathione redox cycle-dependent H2O2 degradation activity and the intracellular glutathione level were determined. HUVEC that had been cultured in the presence of higher concentrations of vitamin E had a higher level of H2O2 degradation activity and a higher intracellular content of the reduced form of glutathione (GSH). Therefore, it is suggested that the vitamin E-induced increase in H2O2 degradation activity in HUVEC results from an increase in intracellular GSH level.

A Cu(II)-mediated C-H oxygenation of sterically hindered tripyridine ligands to form triangular Cu(II)3 complexes.

Two sterically hindered tris-pyridyl methane ligands, tris(6-methyl-2-pyridyl)methane (L1) and bis(6-methyl-2-pyridyl)pyridylmethane (L2), are newly synthesized. Under aerobic conditions, Ln (n = 1 or 2) reacts with CuX2 (X = Cl or Br), oxygenated at the methine position to LnOH or LnOMe. The former alcoholate ligand creates trinuclear Cu(II) complexes [Cu3(X)(LnO)3](PF6)2 [(X, n) = (Br, 1) 1, (C1, 1) 2, (Br, 2) 3, or (C1, 2) 4] in which the alkoxide oxygen atoms bridge copper centers. The crystal structures of 1-4 are presented along with their magnetic susceptibility data. The weak antiferromagnetic coupling between the Cu(II) centers in this trinuclear arrangement is due to weak interaction of the magnetic orbitals (dz2) which are oriented along three alternate sides in a hexagon of the Cu3O3 core in 1-4. Under anaerobic conditions, L1 reacts with CuBr2 to form a square pyramidal complex [CuL1Br2] (9) with the ligand facially capping. [Cu(Br)2(L1OMe)] (10) was obtained after the suspension of 9 in MeOH was stirred under air for 48 h. In the presence of cyclohexene, 9 is converted to [Cu(Br)(L1)]m (m = 1 or 2) 5 quantitatively to give trans- 1,2-dibromocyclohexane, indicating that Br2 is generated during the reaction. The FAB MS spectrum of [18O]-1 prepared by the reaction of L1 with CuBr2 under 18O2 shows that the ligand of [18O]-1 is L1(18O-.) L1(18OH), L1OCD3, and bis(6-methyl-2-pyridyl) ketone were obtained from reaction of L1 with CuBr2 in CD3OD under 18O2. These results indicate that the origins of the O atom in L1OH and L1OMe are O2 and MeOH, respectively. On the basis of these results, a mechanism of the oxygenation of L1 in the present system will be proposed.

Function of poly(ADP-ribose) polymerase in response to DNA damage: gene-disruption study in mice.

To elucidate the biological functions of poly(ADP-ribose) polymerase (PARP, [EC 2.4.2.30]) in DNA damage responses, genetic and biochemical approaches were undertaken. By disrupting exon 1 of the mouse PARP gene by a homologous recombination, PARP-deficient mouse embryonic stem (ES) cell lines and mice could be produced without demonstrating lethality. PARP-/- ES cells showed complete loss of PARP activity and increased sensitivity to gamma-irradiation and an alkylating agents, indicating a physiological role for PARP in the response to DNA damage. p53, a key molecule in cellular DNA damage response, was found to stimulate PARP activity and became poly(ADP-ribosyl)ated in the presence of damaged DNA. However, PARP-/- ES cells showed p21 and Mdm-2 mRNA induction following gamma-irradiation, indicating that PARP activity is not indispensable for p21 and Mdm-2 mRNA induction in the established p53-cascade. On the other hand, in a reconstituted reaction system, purified PARP from human placenta suppressed the pRB-phosphorylation activity in the presence of NAD and damaged DNA. Human PARP expressed in E. coli showed a similar effect on pRB-phosphorylation activity of cdk2. These findings suggest a direct involvement of PARP in the regulation of cdk activity for cell-cycle arrest.

High concentration of glucose causes impairment of the function of the glutathione redox cycle in human vascular smooth muscle cells.

We demonstrated that high glucose reduced H2O2 scavenge activity in human vascular smooth muscle cells. In the cells exposed to high glucose, the intracellular glutathione content decreased, although the NADPH content was unchanged. The rate of uptake of cystine, which is a rate-limiting precursor of the glutathione synthesis, decreased in the high glucose group compared with the control group. These decreases were shown to be dependent on glucose concentration. It was suggested that high glucose causes impairment of the function of the glutathione redox cycle in human vascular smooth muscle cells, resulting in reduced H2O2 scavenge activity.