Evolutionary constraints on chaperone-mediated folding provide an antiviral approach refractory to development of drug resistance

The genome diversity of RNA viruses allows for rapid adaptation to a wide variety of adverse conditions. Accordingly, viruses can escape inhibition by most antiviral compounds targeting either viral or host factors. Here we exploited the capacity of RNA viruses for rapid adaptation to explore the evolutionary constraints of chaperone-mediated protein folding. We hypothesized that inhibiting a host molecular chaperone required for folding of a viral protein would force the virus to evolve an alternate folding strategy. We identified the chaperone Hsp90 as an essential factor for folding and maturation of picornavirus capsid proteins. Pharmacological inhibition of Hsp90 impaired the replication of poliovirus, rhinovirus, and coxsackievirus in cell culture. Strikingly, anti-Hsp90 treatment did not yield drug-resistant viruses, suggesting that the complexity of capsid folding precludes the emergence of alternate folding pathways. These results reveal tight evolutionary constraints on chaperone-mediated protein folding, which may be exploited for viral inhibition in vivo. Indeed, Hsp90 inhibitors drastically reduced poliovirus replication in infected animals without the emergence of drug-resistant escape mutants. We propose that targeting folding of viral proteins may provide a general antiviral strategy that is refractory to development of drug resistance.     

Neural Representations of Visual Words and Objects: A Functional MRI Study on the Modularity of Reading and Object Processing

There have been several studies supporting the notion of a ventral-dorsal distinction in the primate cortex for visual object processing, whereby the ventral stream specializes in object identification, and the dorsal stream is engaged during object localization and interaction. There is also a growing body of evidence supporting a ventral stream that specializes in lexical (i.e., whole-word) reading, and a dorsal stream that is engaged during sub-lexical reading (i.e., phonetic decoding). Here, we consider the extent to which word-reading processes are located in regions either intersecting with, or unique from, regions that sub-serve object processing along these streams. Object identification was contrasted with lexical-based reading, and object interaction processing (i.e., deciding how to interact with an object) was contrasted with sub-lexical reading. Our results suggest that object identification and lexical-based reading are largely ventral and modular, showing mainly unique regions of activation (parahippocampal and occipital-temporal gyri function associated with object identification, and lingual, lateral occipital, and posterior inferior temporal gyri function associated with lexical-based reading) and very little shared activation (posterior inferior frontal gyrus). Object interaction processing and phonetic decoding are largely dorsal, and show both modular regions of activation (more lateralized to the dorsal-frontal right hemisphere for pseudohomophone naming, and more to the dorsal-frontal left hemisphere for the object interaction task) as well as significant shared regions of processing (precentral gyri, left inferior frontal cortex, left postcentral gyrus, left lateral occipital cortex, and superior posterior temporal gyri). Given that the perceptual experimental conditions show primarily modular and very little shared processing, whereas the analytical conditions show both substantial modular and shared processing, we discuss a reconsideration of “modularity of mind” which involves a continuum between strictly modular processing and varying degrees of shared processing, and which also depends on the nature of the tasks compared (i.e., perceptual versus analytical).     

A familial inverted duplication 2q33-q34 identified and delineated by multiple cytogenetic techniques

We describe a unique family with two children having a delay in psychomotor development. In both children we identified an interstitial duplication dup(2)(q34q33) using multiple, complementary molecular cytogenetic techniques. Comparative genomic hybridisation (CGH) and array-CGH were used to determine the size and the location of the duplicated region, the orientation of the duplicated region was identified with fluorescence in situ hybridisation (FISH). Both parents demonstrated a normal karyotype and normal CGH and array-CGH-profiles. However, FISH on peripheral blood cells from the mother showed the inv dup(2) in 9% of metaphases and 19% of interphase nuclei. To our knowledge this is the first report of a mosaic carrier of duplication in the long arm of chromosome 2. The finding of chromosomal mosaicism of at least 19% in the mother increases the recurrence risk. The exact characterisation of the inv dup(2) with FISH probes enabled us to offer a reliable prenatal FISH test. Comparison of the clinical features of the two children with those of previously described cases supports the hypothesis that the characteristic facial phenotype is linked to the distal part of the 2q33-q37 region. This report illustrates that in case of two sibs with an identical structural chromosomal abnormality the possibility of parental chromosomal mosaicism must be thoroughly investigated.     

Does normal developmental expression of psychosis combine with environmental risk to cause persistence of psychosis? A psychosis proneness-persistence model

BACKGROUND: Research suggests that low-grade psychotic experiences in the general population are a common but transitory developmental phenomenon. Using two independent general population samples, the hypothesis was examined that common, non-clinical developmental expression of psychosis may become abnormally persistent when synergistically combined with developmental exposures that may impact on behavioural and neurotransmitter sensitization such as cannabis, trauma and urbanicity. METHOD: The amount of synergism was estimated from the additive statistical interaction between baseline cannabis use, childhood trauma and urbanicity on the one hand, and baseline psychotic experiences on the other, in predicting 3-year follow-up psychotic experiences, using data from two large, longitudinal, random population samples from the Netherlands [The Netherlands Mental Health Survey and Incidence Study (NEMESIS)] and Germany [The Early Developmental Stages of Psychopathology (EDSP) study]. RESULTS: The 3-year persistence rates of psychotic experiences were low at 26% in NEMESIS and 31% in EDSP. However, persistence rates were progressively higher with greater baseline number of environmental exposures in predicting follow-up psychotic experiences (chi2=6.9, df=1, p=0.009 in NEMESIS and chi2=4.2, df=1, p=0.04 in EDSP). Between 21% and 83% (NEMESIS) and 29% and 51% (EDSP) of the subjects exposed to both environmental exposures and psychotic experiences at baseline had persistence of psychotic experiences at follow-up because of the synergistic action of the two factors. CONCLUSION: The findings suggest that environmental risks for psychosis act additively, and that the level of environmental risk combines synergistically with non-clinical developmental expression of psychosis to cause abnormal persistence and, eventually, need for care.     

Polyomavirus BK non-coding control region rearrangements in health and disease

BACKGROUND: BK virus is an increasingly recognized pathogen in transplanted patients. DNA sequencing of this virus shows considerable genomic variability. METHODS: To understand the clinical significance of rearrangements in the non-coding control region (NCCR) of BK virus (BKV), we report a meta-analysis of 507 sequences, including 40 sequences generated in our own laboratory, for associations between rearrangements and disease, tissue tropism, geographic origin, and viral genotype. RESULTS: NCCR rearrangements were less frequent in (a) asymptomatic BKV viruria compared to patients viral nephropathy (1.7% vs. 22.5%), and (b) viral genotype 1 compared to other genotypes (2.4% vs. 11.2%). Rearrangements were commoner in malignancy (78.6%), and Norwegians (45.7%), and less common in East Indians (0%), and Japanese (4.3%). A surprising number of rearranged sequences were reported from mononuclear cells of healthy subjects, whereas most plasma sequences were archetypal. This difference could not be related to potential recombinase activity in lymphocytes, as consensus recombination signal sequences could not be found in the NCCR region. CONCLUSIONS: NCCR rearrangements are neither required nor a sufficient condition to produce clinical disease. BKV nephropathy and hemorrhagic cystitis are not associated with any unique NCCR configuration or nucleotide sequence.     

Programmed death-1 blockade enhances expansion and functional capacity of human melanoma antigen-specific CTLs

Negative co-stimulatory signaling mediated via cell surface programmed death (PD)-1 expression modulates T and B cell activation and is involved in maintaining peripheral tolerance. In this study, we examined the effects of a fully human PD-1-abrogating antibody on the in vitro expansion and function of human vaccine-induced CD8+ T cells (CTLs) specific for the melanoma-associated antigens glycoprotein 100 (gp100) and melanoma antigen recognized by T cells (MART)-1. PD-1 blockade during peptide stimulation augmented the absolute numbers of CD3+, CD4+, CD8+ and gp100/MART-1 MHC:peptide tetramer+ CTLs. This correlated with increased frequencies of IFN-gamma-secreting antigen-specific cells and augmented lysis of gp100+/MART-1+ melanoma targets. PD-1 blockade also increased the fraction of antigen-specific CTLs that recognized melanoma targets by degranulation, suggesting increased recognition efficiency for cognate peptide. The increased frequencies and absolute numbers of antigen-specific CTLs by PD-1 blockade resulted from augmented proliferation, not decreased apoptosis. Kinetic analysis of cytokine secretion demonstrated that PD-1 blockade increased both type-1 and type-2 cytokine accumulation in culture without any apparent skewing of the cytokine repertoire. These findings have implications for developing new cancer immunotherapy strategies.     

The evaluation of genetic tests

Scientific advances in genetics and molecular biology have been very successful in advancing our knowledge of biological mechanisms in health and disease, and in catalysing a variety of technological innovations. The number of genetic tests available has consequently increased exponentially over the last few years. Their development has not been accompanied by processes and systems to evaluate these tests in a proper and formal manner to establish their clinical validity and utility. A framework for the evaluation of genetic tests has been developed. This paper reviews the current practice of genetic test evaluation, highlighting the limitations and future challenges in this area of public health.     

Patient satisfaction in 21st century medicine: revolution or evolution?

The Moment-of-Truth (MOT) patient satisfaction system was created to address each patient's medical care and service needs at the "point-of-care," before the patient leaves the medical facility. The MOT system is patient-centered by actively involving each patient in his or her own healthcare evaluation, planning, and continuous quality improvement. Patient needs are aligned with the required healthcare resources, which simultaneously produce information that can be acted upon "immediately," at the point-of-care, with "a sense of urgency"-addressing patient expectations each and every time the patient encounters the healthcare system. Major changes that occurred in medical service delivery at Hudson Hospital after implementation of the MOT system included a change in the focus of healthcare delivery toward the patient each and every time medical care or service occurred by placing the patient at the center of the care continuum; the ability to capture and react to what the patient needed at the place and time the patient needed it; and the incorporation of patient satisfaction as a way of doing business, throughout the healthcare organization. Results in 2007 to date have averaged 98% among responding patients indicating that they would recommend the Hudson Hospital to family and friends.