Diagnostic Usefulness of APRI and FIB-4 for the Prediction of Liver Fibrosis After Liver Transplantation in Patients Infected with Hepatitis C Virus.

BACKGROUND: Aspartate transaminase-to-platelet ratio index (APRI) and fibrosis-4 (FIB-4) are well known as representative indirect serum biomarkers related to liver fibrosis. The usefulness of these markers for the diagnosis of liver fibrosis after liver transplantation (LT) in hepatitis C virus (HCV)-infected patients and the influence of splenectomy were investigated. METHODS: From June 2003 to May 2014, 31 HCV-infected patients who underwent LT and postoperative follow-up liver biopsies were included in this study. The association between liver fibrosis and serum biomarkers and the influence of splenectomy on APRI and FIB-4 were also investigated. RESULTS: A total of 195 biopsy specimens were collected, and liver fibrosis was identified as: F0, 59.7%; F1, 34.1%; and F2, 6.3%. Both APRI and FIB-4 were significantly higher in patients who showed F1 and F2 in liver biopsy specimen than F0 (P values, .009 and .022, respectively); sensitivity and specificity of APRI were, respectively, 63.4% and 66.7%, and those of FIB-4 were 57.7% and 69.6%. In 11 patients (35.5%) who underwent splenectomy at the time of LT, the cutoff values for APRI and FIB-4 were 0.61 and 1.41, which were significantly lower than the corresponding values (1.00 and 3.64) of patients without splenectomy. CONCLUSIONS: APRI and FIB-4 could effectively estimate liver fibrosis after LT for HCV-related liver disease. For LT patients with splenectomy, APRI and FIB-4 were also useful to estimate liver fibrosis, but the standard values should be adjusted lower than those for patients without splenectomy.

Core I97L mutation in conjunction with P79Q is associated with persistent low HBV DNA and HBs antigen clearance in patients with chronic hepatitis B.

OBJECTIVES: When considering treatment for chronic hepatitis B (CHB), it is important to discriminate between patients with persistent low HBV DNA and patients with active hepatitis, who may proceed to cirrhosis. In this study, we sought to identify mutations in patients expected to have persistent low HBV DNA and ultimately exhibit clearance of hepatitis B surface antigen (HBsAg). METHODS: Serum samples were obtained from 33 CHB genotype C patients, divided based on HBV DNA and alanine aminotransferase (ALT) levels following observation for >2 years: Group A (n=10), transient HBV DNA ≥5.0 log copies/mL and ALT ≥120 IU/L; Group B (n=11), persistent HBV DNA <5.0 and ALT <60; and Group C (n=12), persistent HBV DNA <4.0 and ALT <30. Full-length HBV sequences were compared among groups. Subsequently, 82 patients with CHB were evaluated for the I97L mutation and the additional mutation P79Q. We compared cumulative incidences of persistent low HBV DNA and HBsAg clearance in patients with or without I97L and P79Q by the Kaplan-Meier method. RESULTS: Incidence of Core mutation I97L differed significantly among groups: A, 30% (3/10); B, 36.4% (4/11); C, 83.3% (10/12) (p = 0.021). Cumulative incidences of persistent low HBV DNA and HBsAg clearance were significantly higher in patients with I97L than in those with wild-type I97 (p = 0.003 and p = 0.016, respectively), and even higher in those with P79Q. CONCLUSIONS: In patients with CHB, measurement of I97L and additional mutation P79Q would be useful for predicting persistent low HBV DNA, normal ALT, and HBsAg clearance.

Lubricity of gold nanocrystals on graphene measured using quartz crystal microbalance.

In order to test recently predicted ballistic nanofriction (ultra-low drag and enhanced lubricity) of gold nanocrystals on graphite at high surface speeds, we use the quartz microbalance technique to measure the impact of deposition of gold nanocrystals on graphene. We analyze our measurements of changes in frequency and dissipation induced by nanocrystals using a framework developed for friction of adatoms on various surfaces. We find the lubricity of gold nanocrystals on graphene to be even higher than that predicted for the ballistic nanofriction, confirming the enhanced lubricity predicted at high surface speeds. Our complementary molecular dynamics simulations indicate that such high lubricity is due to the interaction strength between gold nanocrystals and graphene being lower than previously assumed for gold nanocrystals and graphite.

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.

Successful Living-Donor Liver Transplantation for Cholestatic Liver Failure Induced by Allopurinol: Case Report.

A 39-year-old man was diagnosed with allopurinol-induced hepatic injury. He did not show any sign of hepatic encephalopathy, but his serum total bilirubin level was >40 mg/dL when he visited the local hospital. The therapeutic effects of initial medical treatments were transient, and both renal function and coagulation ability were gradually deteriorated. Four months after the onset of hepatic injury, he was referred to our hospital for the purpose of liver transplantation (LT). Although he was wasting and severely jaundiced, his consciousness level was not disturbed at all, with normal serum ammonia blood concentration before LT. Owing to allopurinol-induced severe cholestatic liver failure, living-donor LT (LDLT) was performed with the use of a right lobe graft from his younger brother. The explanted liver was extremely enlarged, with a weight of 2,480 g, and severely cholestatic. Microscopic findings were also compatible with drug-induced cholestatic liver injury. He was discharged from hospital 55 days after LDLT, whereas his renal dysfunction remained at 6 months after LT. There are 3 types of pathophysiology of drug-induced hepatotoxicity: hepatocellular, cholestatic, and mixed liver injury. Although allopurinol hepatotoxicity is rare, it can be severe and even fatal. This is the 1st case report of successful LDLT for a patient who had developed allopurinol-induced cholestatic liver failure.

Considerable Risk of Restenosis After Endoscopic Treatment for Hepaticojejunostomy Stricture After Living-Donor Liver Transplantation.

BACKGROUND: There are few reports on the short- and long-term follow-up of endoscopic retrograde cholangiography (ERC) in adult patients with hepaticojejunostomy (HJS) stricture after living-donor liver transplantation (LDLT). METHODS: Nine LDLT recipients underwent ERC with the use of double-balloon endoscopy (DBE) for HJS stricture at Nagoya University Hospital. We assessed the rate of reaching biliary anastomosis, procedure success rate, procedure duration, complications, improvement in liver function test results, and biliary anastomosis patency. RESULTS: In total, 19 ERC procedures with the use of DBE were performed for 9 adult LDLT recipients with HJS stricture from June 2006 to September 2014. Balloon dilation with the use of DBE was successfully performed in 5 of the 9 patients during the 1st procedure. Of the 4 patients in whom DBE-ERC failed to be completed, 3 patients underwent 2nd procedures successfully. Liver function test results were significantly improved in the successful cases. Four patients underwent 2nd DBE-ERC for stricture recurrence at a mean time of 2.3 years after the 1st successful procedure. Of those, 2 patients required 3rd procedures for stricture recurrence after the 2nd procedure. CONCLUSIONS: DBE-ERC is promising as a treatment for HJS stricture in adult LDLT recipients in the short term. However, the DBE-ERC procedure may have a considerable risk of restenosis.

Postoperative Psychiatric Complications in Living Liver Donors.

BACKGROUND: To understand the impact of psychologic variables on donor quality of life, we studied long-term data on postoperative psychiatric complications in living liver donors. This study is a focused psychological investigation of diagnoses, treatments, and long-term clinical courses of living liver donors with psychiatric complications. METHODS: Of the 142 donors who underwent live-donor liver transplantation at Nagoya University Hospital between April 2004 and July 2014, we investigated those without a history of mental illness who had developed such illness after transplantation and required psychiatric treatment. RESULTS: A total of 6 (4.2%) donors developed the following psychiatric complications after transplantation: major depressive disorder (n = 2), panic disorder (n = 2), conversion disorder (n = 1), and substance use disorder (n = 1). Concerning psychiatric treatment, all donors received antianxiety drugs, 3 took antidepressants, and supportive psychiatric therapy was concomitantly provided to all subjects. The average treatment period was 53.3 months. Regarding subject outcomes, 3 donors achieved remission, and the other 3 continued treatment. All subjects showed improvement in Global Assessment of Functioning Scale. CONCLUSION: It is important to accurately diagnose postoperative psychiatric complications and provide long-term treatment in close coordination with transplant surgeons.

Hofstadter's butterfly and the fractal quantum Hall effect in moiré superlattices.

Electrons moving through a spatially periodic lattice potential develop a quantized energy spectrum consisting of discrete Bloch bands. In two dimensions, electrons moving through a magnetic field also develop a quantized energy spectrum, consisting of highly degenerate Landau energy levels. When subject to both a magnetic field and a periodic electrostatic potential, two-dimensional systems of electrons exhibit a self-similar recursive energy spectrum. Known as Hofstadter's butterfly, this complex spectrum results from an interplay between the characteristic lengths associated with the two quantizing fields, and is one of the first quantum fractals discovered in physics. In the decades since its prediction, experimental attempts to study this effect have been limited by difficulties in reconciling the two length scales. Typical atomic lattices (with periodicities of less than one nanometre) require unfeasibly large magnetic fields to reach the commensurability condition, and in artificially engineered structures (with periodicities greater than about 100 nanometres) the corresponding fields are too small to overcome disorder completely. Here we demonstrate that moiré superlattices arising in bilayer graphene coupled to hexagonal boron nitride provide a periodic modulation with ideal length scales of the order of ten nanometres, enabling unprecedented experimental access to the fractal spectrum. We confirm that quantum Hall features associated with the fractal gaps are described by two integer topological quantum numbers, and report evidence of their recursive structure. Observation of a Hofstadter spectrum in bilayer graphene means that it is possible to investigate emergent behaviour within a fractal energy landscape in a system with tunable internal degrees of freedom.

Mutations in the core and NS5A region of hepatitis C virus genotype 1b and correlation with response to pegylated-interferon-alpha 2b and ribavirin combination therapy.

Mutations in two regions of hepatitis C virus (HCV) have been implicated in influencing response to interferon (IFN) therapy. Substitutions in the NS5A region of HCV have been associated with response to IFN therapy, and this region has been known as the IFN sensitivity-determining region (ISDR). The mutations in the core region of HCV have also been reported to predict IFN response. The aim of this study was to investigate whether amino acid substitutions in the core region and ISDR among patients with HCV genotype 1b affect the response to IFN therapy. A total of 213 patients who completed IFN treatment were randomly selected. All patients received pegylated-IFN-alpha 2b once each week, plus oral ribavirin daily for 48 weeks. Of the 213 patients, 117 (54.9%) showed early virologic response (EVR), with HCV-negativity, at 12 weeks. Factors related to EVR on multivariate analysis were non-Gln70 and Leu91 in the core region, and ISDR mutant-type. One hundred and two (47.9%) showed a sustained virologic response (SVR). SVR occurred more frequently in patients without Gln70 (55.4%) than in those with Gln70 (21.3%) (P < 0.0001). SVR was achieved in 43.6% of patients with wild-type ISDR and 62.5% of patients with mutant-type (P = 0.0227). Of the 34 patients who simultaneously had non-Gln70 and mutant-type ISDR, 26 (76.5%) achieved SVR. Factors related to SVR on multivariate analysis were non-Gln70 and ISDR mutant-type. In conclusion, amino acid substitutions in the core region and ISDR were useful for predicting the response to IFN in patients with HCV genotype 1b.

Ezetimibe improves postprandial hyperlipidaemia in patients with type IIb hyperlipidaemia.

BACKGROUND: Postprandial hyperlipidaemia is known to be a high-risk factor for atherosclerotic disease because of rapid and lasting accumulations of triglyceride-rich lipoproteins and remnants. The Niemann-Pick C1-Like 1 (NPC1L1) protein acts as an intestinal cholesterol transporter and ezetimibe, which inhibits NPC1L1, has been used in patients with hypercholesterolaemia. We investigated effects of ezetimibe on fasting lipid and lipoprotein profiles and postprandial hyperlipidaemia in patients with type IIb hyperlipidaemia. MATERIALS AND METHODS: Ezetimibe 10 mg per day was administered in ten patients with type IIb hyperlipidaemia for 2 months, and lipid and lipoprotein profiles were examined during fasting and after an oral fat loading (OFL) test. RESULTS: In the fasting state, ezetimibe significantly decreased not only total cholesterol, low density lipoprotein (LDL)-cholesterol and apolipoproteinB-100 (apoB-100) levels but triglycerides (TG), apoB-48 and remnant lipoprotein cholesterol (RemL-C) levels. High performance liquid chromatography analysis showed that ezetimibe decreased cholesterol and TG levels in the very low density lipoprotein (VLDL) and LDL size ranges as well as apoB-100 levels, suggesting a decrease in numbers of VLDL and LDL particles. After OFL, ezetimibe decreased the area under the curve for TG, apoB-48 and RemL-C. Ezetimibe decreased postprandial elevations of cholesterol and TG levels in the chylomicrons (CM) size range, suggesting that the postprandial production of CM particles was suppressed by ezetimibe. CONCLUSIONS: These findings suggest that ezetimibe improves fasting lipoprotein profiles and postprandial hyperlipidaemia by suppressing intestinal CM production in patients with type IIb hyperlipidaemia and such treatment may prove to be effective in reducing atherosclerosis.

[Extensive educational program for high performance medical technologists].

The education system for medical technologists has recently been revolutionized, their educational periods vary from 2 to 9 years, and some already have doctoral degrees. In such a new situation, our faculty thinks that the most important point for new medical technologists is the ability to have a broad view of the clinical fields, especially the view of patients. Special training in bed-side education and a stint in several divisions, such as the surgical operation room, rehabilitation. radiological examination room, pharmacy, central storage room of medical records, and medical informatics, and so on, of the hospital is a powerful tool to obtain a broad view of the various clinical fields and can be essential for developing high performance medical technologists. As nine years have passed since starting this education, we evaluated this practice through systematic personal communication. As a result, it was found to be extremely effective for many reasons such as having a continuous image of the patient when they examine the blood sample in the hospital laboratory, showing advanced laboratory performance, and having no mental barrier to visiting the wards and so on. The abilities of our alumni are praised highly by many large scale hospitals around the country and 50% of them are working in the clinical laboratory division of these hospitals. About 40% are working in the division of research and development in various companies. We express sincere thanks to the director and all cooperative individuals for this course in the Osaka University Hospital.

Interferon sensitivity-determining region of nonstructural region 5A of hepatitis C virus genotype 1b correlates with serum alanine aminotransferase levels in chronic infection.

The mutations in the interferon (IFN) sensitivity-determining region (ISDR) of nonstructural region 5A (NS5A) of hepatitis C virus (HCV) have been correlated with response to IFN therapy. NS5A appears to disrupt a host antiviral pathway that plays a role in suppressing virus replication and protects hepatocytes from apoptosis. We assessed whether ISDR correlates with viral load and serum alanine aminotransferase (ALT) levels. Serum viral load and ALT levels were prospectively measured bimonthly by HCV core protein assay and monthly, respectively, for 22 months in 87 patients chronically infected with HCV genotype 1b. ISDR of HCV was directly sequenced from the products of reverse transcription and polymerase chain reaction of HCV RNA. Five patients had four or more substitutions (mutant type), 33 had 1-3 (intermediate type), and 49 had no substitutions (wild type) in ISDR. The numbers of substitutions in ISDR were inversely correlated with mean viral load over a 22-month period (r = 0.292, P = 0.0060) and directly with mean serum ALT levels (r = 0.360, P = 0.0006). The numbers of substitutions in ISDR was significantly larger in the patients with changes of viral load more than fivefold during the 22 months (1.4 +/- 2.4) than in those without changes (0.6 +/- 0.8) (P = 0.0188). The present study demonstrates that the patients with more substitutions in ISDR had significantly higher serum ALT levels and smaller viral load. These results suggest that NS5A with more substitutions in ISDR may lose the ability to block host antiviral pathways and to protect hepatocytes from apoptosis.

Novel LPL mutation (L303F) found in a patient associated with coronary artery disease and severe systemic atherosclerosis.

BACKGROUND: Patients with lipoprotein lipase (LPL) deficiency had been generally thought to be spared accelerated atherosclerosis in spite of a marked elevation of plasma triglyceride levels. However, it has been recently reported that some heterozygous and homozygous LPL-deficient patients are associated with premature atherosclerosis. In this paper, we report a 55-year-old type I hyperlipidaemic patient with a novel missense mutation in the LPL gene. PATIENT AND RESULTS: The patient had suffered from coronary artery disease, abdominal aortic aneurysm, and stenoses of the bilateral renal arteries and superficial femoral arteries. Sequencing of the genomic DNA revealed that the patient was a homozygote for the mutation, a G to C transition at nucleotide position 1069 in the exon 6, resulting in an amino acid substitution of Phe for Leu303 (L303F). Approximately 6% and approximately 40% of normal LPL activity and LPL mass, respectively, were detected in the patient's postheparin plasma. An in vitro expression study demonstrated that COS7 cells transfected with L303F mutant cDNA produced a 40% amount of LPL protein in cell lysates compared with normal cDNA, but no protein was detected in the media. Lipoprotein lipase activity was completely absent in both lysates and media of the cells transfected with the mutant cDNA, suggesting that this mutation in the LPL gene results in the production of a functionally inactive protein. CONCLUSION: This case suggests that the LPL missense mutation (L303F), which impairs lipolysis but preserves the LPL mass, is proatherogenic.

A patient with chronic hepatitis C who obtained sustained response by retreatment of interferon after decrease of viral load and mutation in interferon sensitivity determining region.

A 44-year-old man with chronic hepatitis C received three courses of interferon (IFN) therapy. HCV genotype was 1b, viral load was 1,200 kcopies/ml and interferon sensitivity determining region (ISDR) was the intermediate type before the 1st IFN therapy. The 1st and 2nd IFN therapies resulted in failure to yield a sustained response. Seven years after from the 1st therapy, viral load had decreased to 15 kcopies/ml and ISDR had changed to mutant type. The 3rd IFN therapy yielded sustained response. Thus, we should consider retreatment with IFN when a decrease of the viral load and change of ISDR to mutant type are observed.

Drug interaction between simvastatin and itraconazole in male and female rats.

Taking into account the species and sex differences in drug interactions based on the inhibition of cytochrome P450 (P450)-mediated drug metabolism, we examined whether the interaction between simvastatin and itraconazole observed in humans could also occur in rats, the most commonly used animal species for pharmacokinetic studies. Itraconazole inhibited the in vitro metabolism of simvastatin in female rat liver microsomes, but not in male rat liver microsomes. Using anti-P450 antisera, the main P450 isozyme responsible for the metabolism of simvastatin was identified as CYP3A in female rats and CYP2C11 in male rats. Therefore, the sex difference in the inhibition of simvastatin metabolism by itraconazole seems to be caused by a difference in the P450 isozymes responsible for the metabolism of simvastatin in male and female rats and the different ability of itraconazole to inhibit CYP3A and CYP2C11. In addition, the effect of itraconazole on the pharmacokinetics of simvastatin in rats was also investigated. The area under the curve value of simvastatin was increased approximately 1.6-fold by the concomitant use of itraconazole (50 mg/kg) in female rats, whereas in male rats, itraconazole had no effect. In conclusion, it was found that the results obtained in male rats did not reflect the results in humans as far as the inhibition of simvastatin metabolism by itraconazole was concerned. The P450 isozymes involved in the metabolism of drugs should be taken into consideration when rats are used as a model animal for humans in the investigation of drug interactions.

Roles of plasma lipid transfer proteins in reverse cholesterol transport.

Plasma lipid transfer proteins include plasma cholesteryl ester transfer protein (CETP) and phospholipid transfer protein (PLTP). Plasma CETP facilitates the transfer of cholesteryl ester (CE) from high-density lipoprotein (HDL) to apolipoprotein (apo) B-containing lipoproteins, and is a key protein in reverse cholesterol transport which protects vessel walls from atherosclerosis. The importance of plasma CETP in lipoprotein metabolism was highlighted by the discovery of CETP-deficient subjects with a marked hyperalphalipoproteinemia (HALP). The deficiency of CETP causes various abnormalities in the concentration, composition, and functions of both HDL and low-density lipoprotein (LDL). Although the significance of CETP in terms of atherosclerosis has been controversial, the in vitro evidence showed that large CE-rich HDL particles in CETP deficiency are defective in cholesterol efflux. Recent epidemiological studies in Japanese-Americans and in Omagari area where HALP subjects with the intron 14 splicing defect of CETP gene are markedly frequent, have demonstrated an increased incidence of coronary atherosclerosis in CETP-deficient patients. Similarly, scavenger receptor BI (SR-BI) knockout mice show a marked increase in HDL-cholesterol but accelerated atherosclerosis in atherosclerosis-susceptible mice. Thus, CETP deficiency is a state of impaired reverse cholesterol transport which may possibly lead to the development of atherosclerosis. PLTP transfers phospholipids from triglyceride (TG)-rich lipoproteins to HDL during lipolysis. Human plasma PLTP has a 20% sequence homology to human CETP and human PLTP gene has a marked similarity in the exon-intron organization. Both CETP and PLTP belong to the lipid transfer/lipopolysaccharide binding protein (LBP) gene family, which also includes LBP and bactericidal/permeability-increasing protein (BPI). Although these 4 proteins possess different physiological functions, they share marked biochemical similarities. The current review will also focus on the molecular genetics and function of plasma lipid transfer proteins, including CETP and PLTP.

Adipocyte-derived plasma protein, adiponectin, suppresses lipid accumulation and class A scavenger receptor expression in human monocyte-derived macrophages.

BACKGROUND: Excessive lipid accumulation in macrophages plays an important role in the development of atherosclerosis. Recently, we discovered an adipocyte-specific plasma protein, adiponectin, that is decreased in patients with coronary artery disease. We previously demonstrated that adiponectin acts as a modulator for proinflammatory stimuli and inhibits monocyte adhesion to endothelial cells. The present study investigated the effects of adiponectin on lipid accumulation in human monocyte-derived macrophages. METHODS AND RESULTS: Human monocytes were differentiated into macrophages by incubation in human type AB serum for 7 days, and the effects of adiponectin were investigated at different time intervals. Treatment with physiological concentrations of adiponectin reduced intracellular cholesteryl ester content, as determined using the enzymatic, fluorometric method. The adiponectin-treated macrophages contained fewer lipid droplets stained by oil red O. Adiponectin suppressed the expression of the class A macrophage scavenger receptor (MSR) at both mRNA and protein levels by Northern and immunoblot analyses, respectively, without affecting the expression of CD36, which was quantified by flow cytometry. Adiponectin reduced the class A MSR promoter activity, as measured by luciferase reporter assay. Adiponectin treatment dose-dependently decreased class A MSR ligand binding and uptake activities. The mRNA level of lipoprotein lipase as a marker of macrophage differentiation was decreased by adiponectin treatment, but that of apolipoprotein E was not altered. Adiponectin was detected around macrophages in the human injured aorta by immunohistochemistry. CONCLUSIONS: The adipocyte-derived plasma protein adiponectin suppressed macrophage-to-foam cell transformation, suggesting that adiponectin may act as a modulator for macrophage-to-foam cell transformation.

A comparison of the effects of 3-hydroxy-3-methylglutaryl-coenzyme a (HMG-CoA) reductase inhibitors on the CYP3A4-dependent oxidation of mexazolam in vitro.

HMG-CoA reductase inhibitors can be divided into two groups: those administered as the prodrug, i.e., the lactone form (e.g., simvastatin and lovastatin), and those administered in the active form, i.e., the acid form (e.g., pravastatin, fluvastatin, atorvastatin, and cerivastatin). In this study, the influence of the lactone and acid forms of various HMG-CoA reductase inhibitors on metabolism by CYP3A4, a major cytochrome P450 isoform in human liver, was investigated by determining the in vitro inhibition constant (K(i) value) using an antianxiety agent, mexazolam, as a probe substrate. In human liver microsomes, all the lactone forms tested inhibited the oxidative metabolism of mexazolam more strongly than did the acid forms, which have lower partition coefficient (logD(7.0)) values. In addition, the degree of inhibition of mexazolam metabolism tended to increase with an increasing logD(7.0) value of the HMG-CoA reductase inhibitors among the lactone and acid forms. In particular, pravastatin (acid form), which has the lowest logD(7.0) value, failed to inhibit CYP3A4 activity. Taking account of the lipophilicity of the inhibitors, in conjunction with the CYP3A4-inhibitory activity, could be very useful in predicting drug interactions between substrates of CYP3A4 and HMG-CoA reductase inhibitors.

Mutations in interferon sensitivity-determining region of hepatitis C virus: its relation to change in viral load.

OBJECTIVE: Interferon sensitivity-determining region (ISDR) in nonstructural region 5A of hepatitis C virus (HCV) genotype-1b has been reported to be associated with viral load. Viral load is usually small in the patients with mutant type (four or more amino acid substitutions, compared with HCV-J) and large in those with wild (identical to HCV-J) or intermediate type (from one to three amino acid substitutions). A possible correlation was investigated between mutations in ISDR and alterations of viral load during the course of disease. METHODS: The sequences of ISDR were determined in eight patients with significant changes of viral load and in 11 patients without changes. RESULTS: In two of the eight patients with significant alterations of viral load, ISDR sequences changed significantly. In one patient whose viral load increased after a course of interferon therapy, the number of substitutions, compared with HCV-J, decreased from five to zero or one; the type of ISDR converted from mutant type to wild or intermediate type. In one patient whose viral load decreased significantly after two courses of interferon therapy, the number of substitutions increased from one to six; ISDR changed from intermediate type to mutant type. In the remaining six patients with changes of viral load and in the other 11 patients without changes, the sequences of ISDR did not change significantly. CONCLUSIONS: The mutations in ISDR are one of the viral factors involved in the changes in viral load during the course of disease, although the majority of other factors involved are still unknown.

Apolipoprotein E inhibition of vascular smooth muscle cell proliferation but not the inhibition of migration is mediated through activation of inducible nitric oxide synthase.

Initial experiments revealed that low concentrations of apolipoprotein (apo) E (0.1 to 5 microg/mL) were effective in inhibiting platelet-derived growth factor (PDGF)-directed smooth muscle cell (SMC) migration by 60% to 80%. In contrast, higher concentrations of apoE, at 25 and 50 microg/mL, were necessary to achieve similar inhibition of PDGF-induced SMC proliferation. The potential role of nitric oxide (NO) in mediating the inhibitory effects of apoE was explored. Results showed that, although 0.1 to 5 microg/mL of apoE had no effect on NO production by SMCs, physiological concentrations of apoE (25 to 50 microg/mL) enhanced NO synthesis by 2-fold in a dose-dependent manner (P<0.001). Reverse transcription-polymerase chain reaction amplification of RNA obtained from control and apoE-treated SMCs demonstrated a direct role of apoE in activating inducible nitric oxide synthase (iNOS) gene expression. The apoE-induced nitric oxide production was significantly reduced by coincubation of the cells with aminoguanidine or N(G)-monomethyl-L-arginine (P<0.05) or with antisense iNOS oligodeoxynucleotides (P<0.01). Moreover, the inhibition of iNOS was shown to overcome apoE suppression of PDGF-induced vascular SMC proliferation. However, apoE suppression of PDGF-directed SMC migration was not affected by these treatments. Taken together, these results document that apoE exerts its inhibitory effects on cell proliferation via activation of iNOS. However, apoE inhibition of cell migration is mediated by a mechanism independent of iNOS activation.