Assessment of the Efficacy of Reducing Peginterferon Alfa-2a and Ribavirin Dose on Virologic Response in Koreans with Chronic Hepatitis C

BACKGROUND/AIMS: The virologic response of Koreans to combination therapy for chronic hepatitis C is similar to westerns; however, dose modification occurs more frequently in Koreans. We evaluated the rates of peginterferon alpha-2a and ribavirin dose modifications and their effect on the virologic response in Koreans. METHODS: Patients with detectable HCV RNA and enrolled from multicenters were treated with peginterferon alpha-2a (180 microgram/week) and ribavirin (800 mg/day) for 24 weeks (genotype non-1, n=37) or peginterferon alpha-2a (180 microgram/week) and ribavirin (1,000-1,200 mg/day) for 48 weeks (genotype 1, n=55). RESULTS: Early virologic response (EVR) and sustained virologic response (SVR) were 77.2% (genotype 1, 75%; non-1, 81%) and 66.3% (genotype 1, 56%; non-1, 81%), respectively. The frequency of dose modification was 32.6% within the first 12 weeks and 52.2% during the entire treatment period. No difference was found in SVR regardless of dose modification. However, the SVR for patients using > or =80% of the peginterferon dose was significantly higher than for those using <80% (81.3 vs. 50.0%, p=0.007), despite varying ribavirin doses. No difference was found in SVR regardless of whether the ribavirin dose was <80% or not. These results did not change based on genotype. CONCLUSIONS: We suggest that using at least 80% of the peginterferon alpha-2a dose in Koreans not only maintains SVR but also reduces drug side effects during the entire treatment period. A lower dose of ribavirin may be as efficacious as a standard doseope

Fatal Neutropenic Enterocolitis during Pegylated Interferon and Ribavirin Combination Therapy for Chronic Hepatitis C Virus Infection

It is known that neutropenia caused by combination pegylated interferon plus ribavirin therapy for hepatitis C virus (HCV) infection is well tolerated and carries a negligible risk of infection. Neutropenic enterocolitis is encountered most frequently in patients with hemato-oncologic diseases who are undergoing intensive chemotherapy. However, little information exists regarding this life-threatening event in the setting of HCV therapy. We present here an unusual case of fatal neutropenic enterocolitis in a cirrhotic patient receiving combination therapy for HCV infection. This is the first report of a death from neutropenic enterocolitis associated with treatment for chronic HCV infection. The present case suggests that caution should be exercised when continuing HCV therapy in neutropenic patients with advanced fibrosis, and the decision to maintain such therapy should be balanced against the potential for serious adverse events

Recent trends in the treatment of chronic hepatitis C

Pegylated interferon and ribavirin combination therapy is accepted as the standard antiviral treatment for chronic hepatitis C regardless of HCV genotype. This combination therapy achieves higher response rates than previous therapy, but, nevertheless, a large proportion of patients suffer from treatment failure or adverse events. Recent clinical studies of viral kinetics during antiviral treatment have led to the introduction of response-guided therapy, the concept of 'customized therapy depending on viral response', which focuses on modulation of the treatment period depending on the viral response to create a sustained viral response without unnecessary medication and costs. New upcoming direct-acting antivirals (DAAs) maximize response rate, and triple therapy including DAAs along with pegylated interferon and ribavirin combination therapy could soon be the standard therapy. In this article, we reviewed the factors affecting treatment, response guided treatment, retreatment after failure of standard treatment, management of adverse events during treatment, and new treatment options

A model of direction selectivity in the starburst amacrine cell network

Displaced starburst amacrine cells (SACs) are retinal interneurons that exhibit GABAA receptor-mediated and Cl− cotransporter-mediated, directionally selective (DS) light responses in the rabbit retina. They depolarize to stimuli that move centrifugally through the receptive field surround and hyperpolarize to stimuli that move centripetally through the surround (Gavrikov et al, PNAS 100(26):16047–16052, 2003, PNAS 103(49):18793–18798, 2006). They also play a key role in the activity of DS ganglion cells (DS GC; Amthor et al, Vis Neurosci 19:495–509 2002; Euler et al, Nature 418:845–852, 2002; Fried et al, Nature 420:411– 414, 2002; Gavrikov et al, PNAS 100(26):16047–16052, 2003, PNAS 103(49):18793–18798, 2006; Lee and Zhou, Neuron 51:787–799 2006; Yoshida et al, Neuron 30:771–780, 2001). In this paper we present a model of strong DS behavior of SACs which relies on the GABA-mediated communication within a tightly interconnected network of these cells and on the glutamate signal that the SACs receive from bipolar cells (a presynaptic cell that receives input from cones). We describe how a moving light stimulus can produce a large, sustained depolarization of the SAC dendritic tips that point in the direction that the stimulus moves (i.e., centrifugal motion), but produce a minimal depolarization of the dendritic tips that point in the opposite direction (i.e., centripetal motion). This DS behavior, which is quantified based on the relative size and duration of the depolarizations evoked by stimulus motion at dendritic tips pointing in opposite directions, is robust to changes of many different parameter values and consistent with experimental data. In addition, the DS behavior is strengthened under the assumptions that the Cl− cotransporters Na + -K + -Cl − and K + -Cl − are located in different regions of the SAC dendritic tree (Gavrikov et al, PNAS 103(49):18793–18798, 2006) and that GABA evokes a long-lasting response (Gavrikov et al, PNAS 100(26):16047–16052, 2003, PNAS 103(49):18793–18798, 2006; Lee and Zhou, Neuron 51:787–799, 2006). A possible mechanism is discussed based on the generation of waves of local glutamate and GABA secretion, and their postsynaptic interplay as the waves travel between cell compartments

Explicit Logic Circuits Discriminate Neural States

The magnitude and apparent complexity of the brain's connectivity have left explicit networks largely unexplored. As a result, the relationship between the organization of synaptic connections and how the brain processes information is poorly understood. A recently proposed retinal network that produces neural correlates of color vision is refined and extended here to a family of general logic circuits. For any combination of high and low activity in any set of neurons, one of the logic circuits can receive input from the neurons and activate a single output neuron whenever the input neurons have the given activity state. The strength of the output neuron's response is a measure of the difference between the smallest of the high inputs and the largest of the low inputs. The networks generate correlates of known psychophysical phenomena. These results follow directly from the most cost-effective architectures for specific logic circuits and the minimal cellular capabilities of excitation and inhibition. The networks function dynamically, making their operation consistent with the speed of most brain functions. The networks show that well-known psychophysical phenomena do not require extraordinarily complex brain structures, and that a single network architecture can produce apparently disparate phenomena in different sensory systems

Methods for specifying the target difference in a randomised controlled trial : the Difference ELicitation in TriAls (DELTA) systematic review

Peer reviewedPublisher PD

Metabolic Profiling of an Echinostoma caproni Infection in the Mouse for Biomarker Discovery

Consumption of raw fish and other freshwater products can lead to unpleasant worm infections. Indeed, such worm infections are of growing public health and veterinary concern, but they are often neglected, partially explained by the difficulty of accurate diagnosis. In the present study we infected 12 mice with an intestinal worm (i.e., Echinostoma caproni) and collected blood, stool, and urine samples 7 times between 1 and 33 days after the infection. At the same time points, blood, stool, and urine were also sampled from 12 uninfected mice. These biofluid samples were examined with a spectrometer and data were analyzed with a multivariate approach. We observed important differences between the infected and the uninfected control animals. For example, we found an increased level of branched chain amino acids in the stool of infected mice and subsequent depletion in blood plasma. Additionally, we observed changes related to a disturbed intestinal bacterial composition, particularly in urine and stool. The combination of results from the three types of biofluids gave the most comprehensive characterization of an E. caproni infection in the mouse. Urine would be the biofluid of choice for diagnosis of an infection because the ease of sample collection and the high number and extent of changed metabolites

Direction-Selective Circuitry in Rat Retina Develops Independently of GABAergic, Cholinergic and Action Potential Activity

The ON-OFF direction selective ganglion cells (DSGCs) in the mammalian retina code image motion by responding much more strongly to movement in one direction. They do so by receiving inhibitory inputs selectively from a particular sector of processes of the overlapping starburst amacrine cells, a type of retinal interneuron. The mechanisms of establishment and regulation of this selective connection are unknown. Here, we report that in the rat retina, the morphology, physiology of the ON-OFF DSGCs and the circuitry for coding motion directions develop normally with pharmacological blockade of GABAergic, cholinergic activity and/or action potentials for over two weeks from birth. With recent results demonstrating light independent formation of the retinal DS circuitry, our results strongly suggest the formation of the circuitry, i.e., the connections between the second and third order neurons in the visual system, can be genetically programmed, although emergence of direction selectivity in the visual cortex appears to require visual experience