Daclatasvir: the first of a new class of drugs targeted against hepatitis C virus NS5A.

Hepatitis C virus (HCV) infection affects about 160 million people worldwide. It is treated with pegylatedinterferon (peg-IFN) and ribavirin, and in the case of patients affected by genotype 1, also with a protease inhibitor (telaprevir or boceprevir). Despite a good success rate, IFN-based combinations are contraindicated in several patients (e.g. decompensated cirrhosis, patients with psychiatric disorders, severe heart diseases or autoimmune disorders) and are associated with frequent adverse events that ultimately reduce their use. Numerous oral drugs are in an advanced phase of clinical development, and in some cases, in IFN-free combinations. This review focuses on preclinical and clinical data regarding daclatasvir (BMS-790052), which is a highly selective HCV NS5A replication complex inhibitor effective against HCV genotypes 1, 2, 3 and 4. In vitro data show that daclatasvir exerts a very potent antiviral effect against several HCV genotypes. Its pharmacokinetics is optimal and allows once-a-day oral administration. Its adverse event profile is good. Clinical data regarding its efficacy in combination with peg-IFN, ribavirin or other direct antiviral agents are impressive (rates of sustained virological response range between 60% and 100% in treatment-naïve patients). The only drawback of this drug appears to be a relatively low genetic barrier to resistance. In conclusion, daclatasvir, especially in combinations with other antiviral agents, is a very promising drug for the treatment of chronic hepatitis C.

A novel promising therapeutic option against hepatitis C virus: an oral nucleotide NS5B polymerase inhibitor sofosbuvir.

Hepatitis C virus (HCV) infection is one of the main causes of liver disease worldwide. Its treatment is currently based on the combination of peg-interferon, ribavirin, and, for patients with genotype 1, a protease inhibitor (telaprevir or boceprevir). However, interferon-based combinations are not effective in all patients. Moreover, they are contraindicated in patients who cannot receive interferon (e.g. those with decompensated cirrhosis), and are frequently associated with adverse events. Consequently, there is a need to develop new drugs to treat HCV infection. This review focuses on preclinical and clinical data regarding sofosbuvir (GS-7977), a uridine nucleotide analogue inhibitor of HCV NS5 B polymerase that is effective against HCV genotypes 1,2, 3,4 and 6. Thanks to its excellent pharmacokinetic profile, sofosbuvir can be administered in an oral single daily dose. In vitro it exerts a potent antiviral effect against HCV. Clinical data show that combined with peg-interferon and ribavirin for 12 weeks it yields SVR of about 90% in subjects with HCV genotype 1 and about 100% in patients with HCV genotype 2 or 3. Moreover, sofosbuvir and ribavirin administered for 12 weeks yield similar high SVR rate (84% for genotype 1 and 100% for genotype 2/3 patients) as well as sofosbuvir and daclatasvir (an inhibitor of NS5A) which produce SVR rate of about 100% regardless of genotype or of ribavirin employment. Safety and tolerability of sofosbuvir appear to be excellent. In conclusion, sofosbuvir especially in interferon-free combinations represents a very promising option in the treatment of chronic hepatitis C.

Dendritic cell differentiation blocked by primary effusion lymphoma-released factors is partially restored by inhibition of P38 MAPK.

To better understand the molecular mechanisms underlying the dendritic cell (DC) defects in cancer, we analyzed which signaling pathway is implicated in the abnormal monocyte differentiation into DC determined by the presence of Primary effusion lymphoma (PEL) released factors. Our results indicate that the DC, obtained in this condition, together with phenotypic abnormalities and reduced allostimulatory function, showed hyperphosphorylation of signal transducer and activator of transcription 3 (STAT3) and p38 mitogen-activated protein kinase (MAPK) molecules, in comparison to the DC differentiated in the absence of PEL-released factors. The inhibition of p38 MAPK but not of STAT3 phosphorylation, with specific inhibitors, was able to revert the effect of the PEL-released factors on the DC phenotype. This study suggests that p38 MAPK signaling pathway is an important contributor to the abnormal differentiation of DC in PEL.

Telaprevir: a promising protease inhibitor for the treatment of hepatitis C virus infection.

Chronic hepatitis C affects 130,000,000 people worldwide. Hepatitis C virus (HCV) is a single-strand RNA virus responsible for most cases of chronic hepatitis, liver cirrhosis and hepatocellular carcinoma (HCC) in the Western world. The gold standard for the treatment of chronic hepatitis C (combination of pegylated-interferon alpha and ribavirin) results in a sustained virological response (namely, clearance of serum HCV RNA 6 months after therapy withdrawal) in only about half treated patients. Therefore, there is a race to develop new drugs for the treatment of HCV infection. One of the most promising approaches is to use protease inhibitors, i.e. drugs inhibiting NS3/NS4A HCV protease, which plays a crucial role in the viral life cycle. Telaprevir (VX-950) is the protease inhibitor in the most advanced phase of clinical testing. Telaprevir is orally available and when used in monotherapy it induced a median decline of 4 logs of HCV RNA after two weeks of therapy. However, mutants with a lower sensitivity to telaprevir have been demonstrated in a high proportion of patients within 14 days of monotherapy. The drug has been used in clinical trials in combination with pegylated-interferon and ribavirin. This triple combination resulted in a higher rate of SVR but also in a higher rate of side effects (rash, gastrointestinal disorders, and anemia) than standard treatment. This review focuses on the mechanism of action, pharmacokinetics, clinical efficacy, and tolerability of telaprevir, and on possible use of this drug in combination with other drugs for the treatment of HCV infection.

A case of pegylated interferon alpha-related diabetic ketoacidosis: can this complication be avoided?

We report the case of a 42-year-old woman with chronic hepatitis C (genotype 1), who in June 2004 started therapy with pegylated interferon alpha (PEG-IFNalpha) plus ribavirin. Two months later, she discontinued treatment because of polydipsia, polyuria and vomiting leading to a marked dehydration. Biochemical data showed type 1 diabetes mellitus with ketoacidosis, and insulin therapy was started. The patient, who before starting PEG-IFN alpha plus ribavirin therapy tested negative for glutamic acid decarboxylase antibodies (GADAb) and islet cell (ICAb) antibodies, became strongly positive for both autoimmune markers. This case confirms that patients with chronic hepatitis C who do not have baseline markers of pancreatic autoimmunity may develop severe ketoacidosis during treatment with PEG-IFNalpha, as well as with standard IFNalpha. In order to avoid this complication, as no guidelines are available and the pancreatic autoimmunity markers are not routinely analysed, we suggest frequent monitoring (e.g., every one to two weeks) of glycaemic values: e.g., every one to two weeks during the first 3 months (when this complication occurs most frequently) and monthly thereafter so as to identify diabetes at an early stage and before the onset of the appearance of severe ketoacidosis, which is life-threatening.

Treating chronic hepatitis B: today and tomorrow.

Three hundred and fifty million people worldwide are estimated to be chronically infected with hepatitis B virus. 15-40% of these subjects will develop cirrhosis, liver failure or hepatocellular carcinoma during their life. The treatment of chronic hepatitis B has improved dramatically over the last decade thanks to the advent of nucleoside/nucleotide analogues and the use of pegylated interferons. However, these agents have increased the complexity of the management of hepatitis B. Five drugs have been approved for chronic hepatitis B treatment: standard interferon-alpha 2b, pegylated interferon-alpha 2a, lamivudine, adefovir dipivoxil, and entecavir. A definite course of standard or pegylated interferon is administered to induce hepatitis B virus clearance. Unfortunately, these agents are not effective in all patients and are associated with not negligible side effects. Nucleoside or nucleotide analogues that inhibit hepatitis B virus polymerase induce on-treatment suppression of viral replication but patients tend to relapse after cessation of treatment. Consequently, these analogues, which are well tolerated, should be used for prolonged periods, even indefinitely. However, prolonged treatment is associated with a high rate of resistance. The following anti-hepatitis B virus drugs are currently undergoing clinical testing: telbivudine, emtricitabine, tenofovir disoproxil fumarate, clevudine and thymosin-+/-1. Here we will examine the mechanism of action, efficacy, safety, tolerability and emergence of resistance of agents used to treat chronic hepatitis B. We shall also examine the potential of drugs now being tested and of combination treatment.

[Cystic echinococcosis in humans: our clinic experience]. / Idatidosi cistica: una nostra esperienza clinica.

Echinococcosis in humans is a zoonotic infection caused by larval stages of cestode species of the Echinococcus genus. In cystic echinococcosis (CE), caused by Echinococcus granulosus, the liver is the first and the more frequent involved organ, followed by the lung. Heart, spleen, kidney and brain are usually less involved. The finding of a cyst in course of echinococcosis is usually fortuitous, during ultrasound examination, X-ray or CT. The Authors report 4 cases of human CE admitted to the Department of Infectious Diseases University of Naples "Federico II". Each case is peculiar both for the organ involved by the cysts and for the symptomatolgy. The abdominal pain, in case 1 caused by gallstones, allowed, by the ultrasound examination, to find several hydatid cysts in the liver, never symptomatic until then. The woman, in case 2, was operated for cysts in the lung, without receiving pharmacological prophylaxis. The same occurred in case 4, in which the lack of prophylaxis caused very serious relapses. In case 3, the young woman underwent an ultrasound examination because of an abdominal pain. A unique large cyst extended only in the spleen. The specific serology for immunoglobulin anti-E. granulosus resulted positive 1:61 (n.v. < 50). The Albendazole therapy caused the disappareance of pain, quickly. Later, the patient was splenectomized. It's not clear why only the spleen was involved and why the anti-E. granulosus serum levels of were increased only a little. The man, in case 4, was admitted with chest pain and electrocardiographic findings of myocardial anterior ischemia. He underwent surgical treatment of three hepatic cysts by E. granulosus, during the previous year. Two-dimensional echocardiography, transesophageal echocardiography, and cardiac magnetic resonance revealed a round cystic mass, 6 x 6 mm, located in the middle interventricular septum. The cardiac isoenzymes were in the normal ranges, but the anti-E. granulosus immunoglobulins were positive 1:5120 (n.v. < 64). The patient was treated with Albendazole. This caused the almost simultaneous disappearance of the circular cystic and clinical and electrocardiographic findings of myocardial ischemia. A cardiac hydatid cyst is an uncommon lesion, occurring in about 0.4-2% of patients with echinococcosis. In conclusion, Cystic echinococcosis is a problem in Mediterranean regions because of the high population of stray dogs, favourable conditions created by man and, above all, the illegal slaughtering.

Intrahepatic cholestatic jaundice related to administration of ranitidine. A case report with histologic and ultramicroscopic study.

Ranitidine may cause liver injuries ranging from transient, subclinical serum transaminases increase every 100-1,000 treated patients to cholestatic hepatitis in less than 1/100,000. Other H2-receptor antagonists are more dangerous: 11 toxic hepatitis cases have been reported as adverse effect after 1 year of marketed ebrotidine. A 75-year-old male with ischemic cardiopathy history was started on an 8 days treatment of oral ranitidine due to pirosis, without any other changes of therapy; 48 h after drug withdrawal, light-coloured stools, dark urine and icteric scleras developed. On hospital admission, 10 days later, physical examination showed slight hepatomegaly and severe jaundice with skin excoriations followed by serum mixed bilirubin further increase and aminotransferases activities mild rise. Total bilirubin peaked at 381.33 mmol/l (5.1-17.1) and progressively returned to normal, after discharge home, in 3 months and now, 1 year later, there is no sign of liver disease. Ultrasonographic biliary anomalies and the most frequent causes of liver damage were excluded. Liver biopsy confirmed ranitidine as the most likely cause of liver toxicity since histological and ultramicroscopical study revealed a drug-induced picture. We report a rare case of intrahepatic cholestasis jaundice related to ranitidine, a widely used drug. Diagnosis would need an ethically unacceptable rechallange test.

HIV and hepatitis C virus: facts and controversies.

Hepatitis C virus (HCV) infection occurs in about one-third of HIV-seropositive patients and in about 90% of HIV-positive drug abusers. After the introduction of highly active antiretroviral therapy (HAART) and the subsequent reduction in mortality from opportunistic infections, HCV-related liver failure has become a frequent cause of death in HIV-positive patients. In HIV-seropositive patients, the course of HCV infection is accelerated and there is evidence that HCV is an important factor for HIV progression. Consequently, it is important to establish the appropriate treatment for HCV infection in HIV-seropositive patients. This review examines the epidemiology, physiopathology, diagnostics and treatment of HIV/HCV coinfection with particular regard to the impact of HAART.

Improved pore space structure characterization by fusion of relaxation tomography maps.

Quantitative Relaxation Tomography in porous media furnishes maps of internal sections where each pixel represents T1 or T2 of water 1H in the corresponding voxel, so that quantitative information on the pore space structure can be obtained. The porosity can be determined at different length scales by correcting pixel by pixel the signal intensity for T2 decay. Moreover, on the basis of the distribution of T1, the microporosity fraction can be computed, as well as several voxel-average porosities. Since T1 and T2 encode different pieces of information, fusion image techniques can improve the characterization of the pore space, showing simultaneously, on the same image, maps of the two parameters. Examples are given of application to a water-saturated travertine core and to a pig femur. Different kinds of look-up tables were tried by varying two of the three dimensions of the HSV color space in such a way as to optimize both the T1 and T2 contrasts simultaneously.

Myasthenia gravis during low-dose IFN-alpha therapy for chronic hepatitis C.

We describe the case of a 56-year-old man who had high aminotransferase levels and anti-hepatitis C virus (HCV) antibodies. He underwent liver biopsy and biochemical screening to evaluate whether he would benefit from interferon (IFN) treatment. The patient was discharged with a diagnosis of HCV-related active chronic hepatitis, skin porphyria, and type 2 diabetes. On December 5, 1995, he began therapy with recombinant IFN-alpha at a dose of 3 MIU three times a week. He stopped this therapy in February 1996 because of asthenia, diplopia, headache, and anxiety. During IFN therapy, he had normal aminotransferase levels and no detectable HCV RNA, a condition that persists to the present. Between March and May 1996, the patient was admitted several times to a neurology clinic, where myasthenia gravis was diagnosed and treatment with pyridostigmine and cyclosporine was initiated. This case and others indicate that caution should be exercised in administering IFN because low doses can be correlated with myasthenia gravis in patients without malignancies.

Multivariate discriminant function based on six biochemical markers in blood can predict the cirrhotic evolution of chronic hepatitis.

BACKGROUND: Serologic markers have been proposed for monitoring hepatic fibrosis in chronic active liver disease. Because none of these markers, when used singly, is totally satisfactory, we developed and evaluated a multivariate approach. METHODS: We studied two cohorts of chronic hepatitis (54 patients) and cirrhosis patients (49 patients) to identify a panel of biochemical markers that discriminates between the two diseases. Using multivariate discriminant analysis, we selected a function, based on the concentrations of six biochemical markers (fibronectin, prothrombin, pseudocholinesterase, alanine aminotransferase, manganese superoxide dismutase, and N-acetyl-beta-glucosaminidase). We then prospectively validated this function on a second temporal cohort of patients. RESULTS: Multivariate discriminant analysis correctly classified 93.7% of patients (94.3% of chronic hepatitis and 92.9% of cirrhosis patients) in the first cohort and 85% of patients (89.5% of chronic hepatitis patients and 81% of cirrhosis patients) in the second cohort. CONCLUSIONS: Discriminant analysis of results of six inexpensive biochemical markers provides a high predictive value for differentiation between liver cirrhosis and chronic hepatitis. Consequently, these biochemical markers condensed into a multivariate discriminant analysis value for each patient provide information that can be contributory for subsequent options during the evolution of the natural history of chronic hepatitis.

Characterisation of crosslinked elastomeric materials by 1H NMR relaxation time distributions.

One of the most critical structural parameters in elastomeric materials is the density of cross-linking between the polymeric chains. This chemical feature greatly affects chain motions and is determinant in controlling mechanical properties of the final product. NMR techniques are widely and efficiently applied to investigation of such materials. In this study we have measured both transverse and longitudinal 1H relaxation times of a series of polybutadiene rubber samples with increasing crosslink density induced by chemical treatment. This approach allowed the observation of T(1) and T(2) decrease with the increase of crosslink density in the samples examined. The data obtained have been analyzed and compared to theoretical models.

Examples of marginal resolution of NMR relaxation peaks using UPEN and diagnostics.

The multiexponential inversion program UPEN by the authors [J. Magn. Reson. 1998; 132: 65-77; Ibid. 2000;147:273-85] employs negative feedback to a regularization penalty to implement variable smoothing when both sharp and broad features appear on a single distribution of relaxation times. This allows a good fit to relaxation data that correspond to a sum of decaying exponentials plus random noise, but it usually does not give a good fit to data that are distorted by systematic errors from instrument problems, which can cause erroneous "resolution" or erroneous non-resolution of peaks. UPEN provides a series of diagnostic parameters to help identify such data problems that can lead to interpretation errors, and, in particular, to warn when a close call on the resolution or non-resolution of nearby peaks might be questionable. Examples are given from a series of T(2) data sets from desiccated bone samples, with examples where the presence of two peaks is required by good data, examples where the presence of two peaks is negated by good data, and examples where the resolution or non-resolution of peaks cannot be trusted because of instrumental distortions revealed by UPEN diagnostic parameters. It is suggested that processing relaxation data with UPEN in nearly real time could permit retaking data while a sample is still available if the diagnostic parameters show instrumental problems.

Effects of hydrophobic treatments of stone on pore water studied by continuous distribution analysis of NMR relaxation times.

The effects of protective hydrophobic products applied to porous media such as stone or mortar vary greatly with the product, the porous medium, and the mode of application. Nuclear Magnetic Resonance (NMR) measurements on fluids in the pore spaces of both treated and untreated samples can give information on the contact of the fluid with the internal surfaces, which is affected by all the above factors. Continuous distributions of relaxation times T(1) and T(2) of water in the pores of both synthetic and natural porous media were obtained before and after hydrophobic treatment. The synthetic porous media are ceramic filter materials characterized by narrow distributions of pore dimensions and show that the treatment does not produce large changes in the relaxation times of the water. For three travertine samples most of a long relaxation time component, presumably from the largest pores, remains after treatment, while the amplitude of an intermediate component is greatly reduced. For three pudding-stone samples, treatment leads to a substantial loss from the long component and an even greater loss from the intermediate component.

Performance evolution of hydrophobic treatments for stone conservation investigated by MRI.

1H-MRI has been applied to the evaluation of the performances of a hydrophobic polymer (Paraloid B72), widely used for the conservation of monumental buildings and other stone artifacts. By this technique it has been possible to visualize the water diffusion in a treated rock material (Pietra di Lecce, a highly porous Italian biocalcarenite) and then indirectly the spatial distribution of the polymer in the rock. The effects of wetting-drying cycles on the hydrophobic efficacy of the acrylic polymer in the inner layers of the rock were also studied. A notable decrease in the water-repellence inside the stone was detected and attributed to a loss of adhesion of the polymer to the substrate, promoted by the action of water.

Loss of preferred mates forces female satin bowerbirds (Ptilonorhynchus violaceus) to increase mate searching.

Variation in mate choice among females can have important consequences for the operation of sexual selection, and can result from differences in the way females search for mates. Our previous work indicates that female satin bowerbirds Ptilonorhynchus violaceus alter their mate-searching patterns according to long-term experience. Females which mate with very attractive males mate with the same males in the following year, thereby reducing their search. In contrast, females which fail to encounter very attractive males typically reject their previous mates and search for more attractive males in the following year, thereby increasing their search. Here we report results from a natural experiment consistent with these observations. Five males, including the most attractive male of 1997, failed to re-establish display sites in 1998, most probably dying over winter. We monitored the mate-searching behaviour of females which mated with these males in 1997 to determine how the loss of attractive mates affects subsequent mate-searching patterns. Females which lost their mates sampled more males compared with their own search patterns in 1997 and with faithful females in 1998. Results from this natural experiment indicate that the loss of attractive and preferred mates forces females to increase their search and provide evidence that long-term experience with males shapes mate-searching behaviour.

Complex mate searching in the satin bowerbird Ptilonorhynchus violaceus.

Mate-choice studies typically focus on male traits affecting female mating decisions, but few studies seek to identify the behavioral rules females use when searching for mates. Current models suggest that females may either directly compare a set of males ("pooled comparison") or compare each male to an internal standard ("sequential-search rule") when judging the suitability of potential mates. Models also differ in other specific aspects, such as the predicted number of sampling bouts initiated and the tendency of females to return to males after previous visits. We monitored 63 female satin bowerbirds, Ptilonorhynchus violaceus, during mate sampling to reconstruct their search patterns. We found that females typically sampled several males and returned to the most attractive male for mating: a behavior consistent with the pooled-comparison tactic. Females, however, varied in the number of males sampled; some visited only one male before mating. We found that this variation can be explained by differences among females in the number of mates, the date mate searching is initiated, and long-term experience with males. Further, females were observed to initiate two distinct sampling bouts, with the rejection of most of their potential mates occurring before the start of the second sampling bout. This suggests that the choices of potential mates are narrowed prior to the second sampling bout and that the later visits may function to reconsider preliminary decisions made during the first sampling bout or to resolve decisions concerning the remaining potential mates. Our results indicate that mate searching is a complex process in which females use multiple sampling bouts to find suitable mates and in which several different factors influence their search behavior.