Expression of divergent methyl/alkyl coenzyme M reductases from uncultured archaea

Methanogens and anaerobic methane-oxidizing archaea (ANME) are important players in the global carbon cycle. Methyl-coenzyme M reductase (MCR) is a key enzyme in methane metabolism, catalyzing the last step in methanogenesis and the first step in anaerobic methane oxidation. Divergent mcr and mcr-like genes have recently been identified in uncultured archaeal lineages. However, the assembly and biochemistry of MCRs from uncultured archaea remain largely unknown. Here we present an approach to study MCRs from uncultured archaea by heterologous expression in a methanogen, Methanococcus maripaludis. Promoter, operon structure, and temperature were important determinants for MCR production. Both recombinant methanococcal and ANME-2 MCR assembled with the host MCR forming hybrid complexes, whereas tested ANME-1 MCR and ethyl-coenzyme M reductase only formed homogenous complexes. Together with structural modeling, this suggests that ANME-2 and methanogen MCRs are structurally similar and their reaction directions are likely regulated by thermodynamics rather than intrinsic structural differences.

Progressive dysbiosis of human orodigestive microbiota along the sequence of gastroesophageal reflux, Barrett's esophagus, and esophageal adenocarcinoma

The incidence of esophageal adenocarcinoma (EA) has drastically increased in the United States since 1970s for unclear reasons. We hypothesized that the widespread usage of antibiotics has increased the procarcinogenic potential of the orodigestive microbiota along the sequence of gastroesophageal reflux (GR), Barrett's esophagus (BE), and EA phenotypes. This case control study included normal controls (NC) and three disease phenotypes GR, BE, and EA. Microbiota in the mouth, esophagus, and stomach, and rectum were analyzed using 16S rRNA gene sequencing. Overall, we discovered 44 significant pairwise differences in abundance of microbial taxa between the four phenotypes, with 12 differences in the mouth, 21 in the esophagus, two in the stomach, and nine in the rectum. Along the GR→BE→EA sequence, oral and esophageal microbiota were more diversified, the dominant genus Streptococcus was progressively depleted while six other genera Atopobium, Actinomyces, Veillonella, Ralstonia, Burkholderia, and Lautropia progressively enriched. In NC, Streptococcus appeared to control populations of other genera in the foregut via numerous negative and positive connections, while in disease states, the rich network was markedly simplified. Inferred gene functional content showed a progressive enrichment through the stages of EA development in genes encoding antibiotic resistance, ligands of Toll-like and NOD-like receptors, nitrate-nitrite-nitric oxide pathway, and acetaldehyde metabolism. The orodigestive microbiota is in a progressive dysbiotic state along the GR-BE-EA sequence. The increasing dysbiosis and antibiotic and procarcinogenic genes in the disease states warrants further study to define their roles in EA pathogenesis. This article is protected by copyright. All rights reserved.

HPViewer: sensitive and specific genotyping of human papillomavirus in metagenomic DNA

Motivation

Shotgun DNA sequencing provides sensitive detection of all 182 HPV types in tissue and body fluid. However, existing computational methods either produce false positives misidentifying HPV types due to shared sequences among HPV, human and prokaryotes, or produce false negative since they identify HPV by assembled contigs requiring large abundant of HPV reads.

Results

We designed HPViewer with two custom HPV reference databases masking simple repeats and homology sequences respectively and one homology distance matrix to hybridize these two databases. It directly identified HPV from short DNA reads rather than assembled contigs. Using 100 100 simulated samples, we revealed that HPViewer was robust for samples containing either high or low number of HPV reads. Using 12 shotgun sequencing samples from respiratory papillomatosis, HPViewer was equal to VirusTAP, and Vipie and better than HPVDetector with the respect to specificity and was the most sensitive method in the detection of HPV types 6 and 11. We demonstrated that contigs-based approaches had disadvantages of detection of HPV. In 1573 sets of metagenomic data from 18 human body sites, HPViewer identified 104 types of HPV in a body-site associated pattern and 89 types of HPV co-occurring in one sample with other types of HPV. We demonstrated HPViewer was sensitive and specific for HPV detection in metagenomic data.

Availability and implementation

HPViewer can be accessed at https://github.com/yuhanH/HPViewer/.

Supplementary information

Supplementary data are available at Bioinformatics online.

Type 1 Diabetes: an Association Between Autoimmunity, the Dynamics of Gut Amyloid-producing E. coli and Their Phages

The etiopathogenesis of type 1 diabetes (T1D), a common autoimmune disorder, is not completely understood. Recent studies suggested the gut microbiome plays a role in T1D. We have used public longitudinal microbiome data from T1D patients to analyze amyloid-producing bacterial composition and found a significant association between initially high amyloid-producing Escherichia coli abundance, subsequent E. coli depletion prior to seroconversion, and T1D development. In children who presented seroconversion or developed T1D, we observed an increase in the E. coli phage/E. coli ratio prior to E. coli depletion, suggesting that the decrease in E. coli was due to prophage activation. Evaluation of the role of phages in amyloid release from E. coli biofilms in vitro suggested an indirect role of the bacterial phages in the modulation of host immunity. This study for the first time suggests that amyloid-producing E. coli, their phages, and bacteria-derived amyloid might be involved in pro-diabetic pathway activation in children at risk for T1D.

Elucidation of drug resistance mutations in Mycobacterium tuberculosis isolates from North India by whole-genome sequencing

OBJECTIVES

Rapid diagnosis of drug-resistant tuberculosis (TB) is required for better patient management and treatment outcomes. Whole-genome sequencing (WGS) can be used to detect single nucleotide polymorphisms (SNPs) and deletions/insertions that are responsible for mostMycobacterium tuberculosis drug resistance. WGS is being performed at scale in high-income countries, but there are limited reports of its use in India.

METHODS

In this study, 33 clinicalM. tuberculosis isolates from the Mycobacterial Repository in Chandigarh underwent WGS. Phenotypic drug susceptibility testing was performed according to World Health Organization (WHO) recommendations. Four isolates were excluded from the analysis due to culture contamination or mislabelling during the study.

RESULTS

Among the remaining 29 isolates, 21 (72.4%) were multidrug-resistant TB (MDR-TB) and 1 (3.4%) was extensively-drug resistant TB (XDR-TB). The most common mutations observed for isoniazid, rifampicin, ofloxacin and kanamycin resistance werekatG(S315T), rpoB(S450L), gyrA(A90V) and rrs(A1401G), respectively. The isolates mainly belonged to lineages 2 and 3, with most MDR-TB among lineage 2 isolates.

CONCLUSION

WGS ofM. tuberculosis isolates allows the detection of drug resistance to all drugs in a single test and also provides insight into the evolution and drug-resistant TB.

MGS-Fast: Metagenomic shotgun data fast annotation using microbial gene catalogs

BACKGROUND

Current methods used for annotating metagenomics shotgun sequencing (MGS) data rely on a computationally intensive and low-stringency approach of mapping each read to a generic database of proteins or reference microbial genomes.

RESULTS

We developed MGS-Fast, an analysis approach for shotgun whole-genome metagenomic data utilizing Bowtie2 DNA-DNA alignment of reads that is an alternative to using the integrated catalog of reference genes database of well-annotated genes compiled from human microbiome data. This method is rapid and provides high-stringency matches (>90% DNA sequence identity) of the metagenomics reads to genes with annotated functions. We demonstrate the use of this method with data from a study of liver disease and synthetic reads, and Human Microbiome Project shotgun data, to detect differentially abundant Kyoto Encyclopedia of Genes and Genomes gene functions in these experiments. This rapid annotation method is freely available as a Galaxy workflow within a Docker image.

CONCLUSIONS

MGS-Fast can confidently transfer functional annotations from gene databases to metagenomic reads, with speed and accuracy.

Environmentally enriched pigs have transcriptional profiles consistent with neuroprotective effects and reduced microglial activity

Environmental enrichment (EE) is widely used to study the effects of external factors on brain development, function and health in rodent models, but very little is known of the effects of EE on the brain in a large animal model such as the pig. Twenty-four young pigs (aged 5 weeks at start of study, 1:1 male: female ratio) were housed in environmentally enriched (EE) pens and provided with additional enrichment stimulation (a bag filled with straw) once daily. Litter, weight and sex matched controls n= (24) were housed in barren (B) conditions. Behaviour was recorded on alternate days from study day 10. After 21 days, RNA-sequencing of the frontal cortex of male piglets culled one hour after the enrichment stimulation, but not those at 4 h after stimulation, showed upregulation of genes involved in neuronal activity and synaptic plasticity in the EE compared to the B condition. This result is mirrored in the behavioural response to the stimulation which showed a peak in activity around the 1 h time-point. By contrast, EE piglets displayed a signature consistent with a relative decrease in microglial activity compared to those in the B condition. These results confirm those from rodents, suggesting that EE may also confer neuronal health benefits in large mammal models, through a potential relative reduction in neuroinflammatory process and increase in neuroprotection driven by an enrichment-induced increase in behavioural activity.

Parkinson's disease and bacteriophages as its overlooked contributors

Recent studies suggest that alterations in the gut phagobiota may contribute to pathophysiological processes in mammals; however, the association of bacteriophage community structure with Parkinson's disease (PD) has not been yet characterized. Towards this end, we used a published dataset to analyse bacteriophage composition and determine the phage/bacteria ratio in faecal samples from drug-naive PD patients and healthy participants. Our analyses revealed significant alterations in the representation of certain bacteriophages in the phagobiota of PD patients. We identified shifts of the phage/bacteria ratio in lactic acid bacteria known to produce dopamine and regulate intestinal permeability, which are major factors implicated in PD pathogenesis. Furthermore, we observed the depletion of Lactococcus spp. in the PD group, which was most likely due to the increase of lytic c2-like and 936-like lactococcal phages frequently present in dairy products. Our findings add bacteriophages to the list of possible factors associated with the development of PD, suggesting that gut phagobiota composition may serve as a diagnostic tool as well as a target for therapeutic intervention, which should be confirmed in further studies. Our results open a discussion on the role of environmental phages and phagobiota composition in health and disease.

Inherited pulmonary cylindromas: extending the phenotype of CYLD mutation carriers

Background

Germline mutations in the tumour suppressor gene CYLD are recognized to be associated with the development of multiple cutaneous cylindromas. We encountered such a patient who presented with breathlessness because of multiple pulmonary cylindromas.

Objectives

To search for clinical and radiological features of multiple pulmonary cylindromas in a cohort of 16 patients with CYLD mutations.

Methods

A retrospective case‐note review was carried out in a tertiary dermatogenetics clinic where CYLD mutation carriers are reviewed on an annual basis. In‐depth investigation was carried out for patients with pulmonary tumours.

Results

Four patients had radiological imaging of their lungs, of which two had multiple pulmonary cylindromas that were confirmed histologically. Serial computed tomography monitoring allowed for pre‐emptive endobronchial laser ablation, preventing major airway obstruction and pulmonary collapse.

Conclusions

Pulmonary cylindromas are an unrecognized, but infrequently symptomatic, aspect of the phenotype in these patients that can have implications for patient care. They should be considered in patients with a high tumour burden that present with respiratory symptoms, and where appropriate, monitored with serial imaging.

What's already known about this topic?

Germline mutations in the tumour suppressor gene CYLD are recognized to be associated with the development of multiple cutaneous cylindromas, spiradenomas and trichoepitheliomas.

Beyond the skin, salivary gland tumours are seen in less than approximately 5% of patients, but otherwise the tropism of this disease is recognized as exclusively cutaneous.

What does this study add?

We report multiple pulmonary cylindromas in two patients out of a series of 16 patients, a previously unreported aspect of this genetic disease.

Deep phenotyping with radiological, histological and genetic approaches provides evidence that supports that these tumours are similar to cutaneous cylindromas and share a cytokeratin signature seen in cutaneous cylindroma.

What is the translational message?

Patients with this rare disease should be investigated if they present with new symptoms of respiratory disease.

These data inform the clinical surveillance and management of patients with this rare condition and also inform the longstanding debate on benign metastases.

https://doi.org/10.1111/bjd.17046 available online

https://goo.gl/Uqv3dl

The Ancient Origins of Neural Substrates for Land Walking

Walking is the predominant locomotor behavior expressed by land-dwelling vertebrates, but it is unknown when the neural circuits that are essential for limb control first appeared. Certain fish species display walking-like behaviors, raising the possibility that the underlying circuitry originated in primitive marine vertebrates. We show that the neural substrates of bipedalism are present in the little skate Leucoraja erinacea, whose common ancestor with tetrapods existed ∼420 million years ago. Leucoraja exhibits core features of tetrapod locomotor gaits, including left-right alternation and reciprocal extension-flexion of the pelvic fins. Leucoraja also deploys a remarkably conserved Hox transcription factor-dependent program that is essential for selective innervation of fin/limb muscle. This network encodes peripheral connectivity modules that are distinct from those used in axial muscle-based swimming and has apparently been diminished in most modern fish. These findings indicate that the circuits that are essential for walking evolved through adaptation of a genetic regulatory network shared by all vertebrates with paired appendages. VIDEO ABSTRACT.

A Dramatic Difference in Global Gene Expression between TCDD-Treated Atlantic Tomcod Larvae from the Resistant Hudson River and a Nearby Sensitive Population

Atlantic tomcod in the Hudson River Estuary bioaccumulate high hepatic burdens of environmental toxicants. Previously, we demonstrated that Hudson River tomcod developed resistance to TCDD and PCB toxicity probably through strong natural selection during their early life-stages for a variant of the Aryl Hydrocarbon Receptor2 (AHR2). Here, we evaluated the genomic consequences of the resistant genotype by comparing global gene expression in larval tomcod from the Hudson River with expression in larvae from a nearby sensitive population (Shinnecock Bay). We developed an annotated draft tomcod genome to explore the effects of multigenerational exposure to toxicants and a functionally impaired AHR2 on the transcriptome. We used the tomcod genome as a reference in RNA-Seq to compare global gene expression in tomcod larvae from the Hudson River and Shinnecock Bay after experimental exposure of larvae to graded doses of TCDD. We found dramatic differences between offspring from the two populations in the number of genes that were differentially expressed at all doses (0.01, 0.1, and 1 ppb) and even in the vehicle controls. At the two lowest TCDD doses, 250 and 1,141 genes were differentially expressed in Shinnecock Bay larvae compared with 14 and 12, respectively, in Hudson River larvae. At the highest dose (1.0 ppb), 934 genes were differentially expressed in Shinnecock Bay larvae and 173 in Hudson River larvae, but only 28 (16%) of affected genes were shared among both populations. Given the large difference between the two populations in the number and identity of differentially expressed genes, it is likely that the AHR2 pathway interacts directly or indirectly with many genes beyond those known in the AHR2 battery and that other regulatory systems may also respond to TCDD exposure. The effects of chronic multi-generational exposure to environmental toxicants on the genome of Hudson River tomcod are much greater than previously expected.

Constraint of the astrophysical ^{26g}Al(p,γ)^{27}Si destruction rate at stellar temperatures

The Galactic 1.809-MeV γ-ray signature from the β decay of ^{26g}Al is a dominant target of γ-ray astronomy, of which a significant component is understood to originate from massive stars. The ^{26g}Al(p,γ)^{27}Si reaction is a major destruction pathway for ^{26g}Al at stellar temperatures, but the reaction rate is poorly constrained due to uncertainties in the strengths of low-lying resonances in ^{27}Si. The ^{26g}Al(d,p)^{27}Al reaction has been employed in inverse kinematics to determine the spectroscopic factors, and hence resonance strengths, of proton resonances in ^{27}Si via mirror symmetry. The strength of the 127-keV resonance is found to be a factor of 4 higher than the previously adopted upper limit, and the upper limit for the 68-keV resonance has been reduced by an order of magnitude, considerably constraining the ^{26g}Al destruction rate at stellar temperatures.

Profiling gene expression to distinguish the likely active diazotrophs from a sea of genetic potential in marine sediments

Nitrogen (N) cycling microbial communities in marine sediments are extremely diverse, and it is unknown whether this diversity reflects extensive functional redundancy. Sedimentary denitrifiers remove significant amounts of N from the coastal ocean and diazotrophs are typically regarded as inconsequential. Recently, N fixation has been shown to be a potentially important source of N in estuarine and continental shelf sediments. Analysis of expressed genes for nitrite reductase (nirS) and a nitrogenase subunit (nifH) was used to identify the likely active denitrifiers and nitrogen fixers in surface sediments from different seasons in Narragansett Bay (Rhode Island, USA). The overall diversity of diazotrophs expressing nifH decreased along the estuarine gradient from the estuarine head to an offshore continental shelf site. Two groups of sequences related to anaerobic sulphur/iron reducers and sulphate reducers dominated libraries of expressed nifH genes. Quantitative polymerase chain reaction (qPCR) and quantitative reverse transcription polymerase chain reaction (qRT-PCR) data shows the highest abundance of both groups at a mid bay site, and the highest nifH expression at the head of the estuary, regardless of season. Several potential environmental factors, including water temperature, oxygen concentration and metal contamination, may influence the abundance and nifH expression of these two bacterial groups.

A review and update on melanocyte stimulating hormone therapy: afamelanotide

Afamelanotide ([Nle4-D-Phe7]-alpha-MSH) is an analog of alpha-melanocyte stimulating hormone given as a subcutaneous injection. Afamelanotide is currently undergoing phase II and III trials in Europe and the US for skin diseases including vitiligo, erythropoietic protoporphyria, polymorphic light eruption and prevention of actinic keratoses in organ transplant recipients. Unregulated analogs and chemicals are being sold online ahead of formal approval. A number of counterfeit chemicals, 'Melanotans' are being sold for tanning purposes. Currently, afamelanotide is already on the market in Italy and Switzerland for patients with erythropoietic protoporphyria. This paper will review the current literature on this promising compound.

Halo nucleus 11Be: a spectroscopic study via neutron transfer

The best examples of halo nuclei, exotic systems with a diffuse nuclear cloud surrounding a tightly bound core, are found in the light, neutron-rich region, where the halo neutrons experience only weak binding and a weak, or no, potential barrier. Modern direct-reaction measurement techniques provide powerful probes of the structure of exotic nuclei. Despite more than four decades of these studies on the benchmark one-neutron halo nucleus 11Be, the spectroscopic factors for the two bound states remain poorly constrained. In the present work, the 10Be(d,​p) reaction has been used in inverse kinematics at four beam energies to study the structure of 11Be. The spectroscopic factors extracted using the adiabatic model were found to be consistent across the four measurements and were largely insensitive to the optical potential used. The extracted spectroscopic factor for a neutron in an nℓj=2s(1/2) state coupled to the ground state of 10Be is 0.71(5). For the first excited state at 0.32 MeV, a spectroscopic factor of 0.62(4) is found for the halo neutron in a 1p(1/2) state.

Expression of muscarinic receptors by human macrophages

Macrophages increase in number and are highly activated in chronic obstructive pulmonary disease (COPD). Muscarinic receptor antagonists inhibit acetylcholine-stimulated release of neutrophilic chemoattractants, suggesting that acetylcholine may regulate macrophage responses. Therefore, expression and function of components of the non-neuronal cholinergic system in monocyte-macrophage cells was investigated. RNA was isolated from monocytes, monocyte-derived macrophages (MDMs), lung and alveolar macrophages from nonsmokers, smokers and COPD patients, and expression of the high-affinity choline transporter, choline acetyltransferase, vesicular acetylcholine transporter and muscarinic receptors (M(1)-M(5)) ascertained using real-time PCR. M(2) and M(3) receptor expression was confirmed using immunocytochemistry. Release of interleukin (IL)-8, IL-6 and leukotriene (LT)B(4) were measured by ELISA or EIA. All monocyte-macrophage cells expressed mRNA for components of the non-neuronal cholinergic system. Lung macrophages expressed significantly more M(1) mRNA compared with monocytes, and both lung macrophages and alveolar macrophages expressed the highest levels of M(3) mRNA. Expression of M(2) and M(3) protein was confirmed in MDMs and lung macrophages. Carbachol stimulated release of LTB(4) from lung macrophages (buffer 222.3 ± 75.1 versus carbachol 1,118 ± 622.4 pg · mL(-1); n = 15, p<0.05) but not IL-6 or IL-8. LTB(4) release was attenuated by the M(3) antagonist, 1,1-dimethyl-4-diphenylacetoxypiperidinium iodide (4-DAMP; half maximal effective concentration 5.2 ± 2.2 nM; n = 9). Stimulation of macrophage M(3) receptors promotes release of LTB(4), suggesting that anti-muscarinic agents may be anti-inflammatory.

A molecular epidemiological study of var gene diversity to characterize the reservoir of Plasmodium falciparum in humans in Africa

BACKGROUND

The reservoir of Plasmodium infection in humans has traditionally been defined by blood slide positivity. This study was designed to characterize the local reservoir of infection in relation to the diverse var genes that encode the major surface antigen of Plasmodium falciparum blood stages and underlie the parasite's ability to establish chronic infection and transmit from human to mosquito.

METHODOLOGY/PRINCIPAL FINDINGS

We investigated the molecular epidemiology of the var multigene family at local sites in Gabon, Senegal and Kenya which differ in parasite prevalence and transmission intensity. 1839 distinct var gene types were defined by sequencing DBLα domains in the three sites. Only 76 (4.1%) var types were found in more than one population indicating spatial heterogeneity in var types across the African continent. The majority of var types appeared only once in the population sample. Non-parametric statistical estimators predict in each population at minimum five to seven thousand distinct var types. Similar diversity of var types was seen in sites with different parasite prevalences.

CONCLUSIONS/SIGNIFICANCE

Var population genomics provides new insights into the epidemiology of P. falciparum in Africa where malaria has never been conquered. In particular, we have described the extensive reservoir of infection in local African sites and discovered a unique var population structure that can facilitate superinfection through minimal overlap in var repertoires among parasite genomes. Our findings show that var typing as a molecular surveillance system defines the extent of genetic complexity in the reservoir of infection to complement measures of malaria prevalence. The observed small scale spatial diversity of var genes suggests that var genetics could greatly inform current malaria mapping approaches and predict complex malaria population dynamics due to the import of var types to areas where no widespread pre-existing immunity in the population exists.

Teaching serial position sequences to monkeys with a delayed matching-to-sample procedure

Comparison was made of two methods for training monkeys to "observe" a two-member serial position sequence by pressing two consecutively lighted keys and then to "report" the sequence by pressing the same two keys in the same order but without the lights. A fading technique involving gradual elimination of brightness cues from "reporting" keys was found more effective than a no-fading procedure in which the cues remained bright during training and then were suddenly removed. Animals that failed to learn to report a new sequence with the no-fading procedure sometimes developed behavior incompatible with that desired. They made repeated and specific errors that prematurely terminated trials of the sequence to-be-learned, even though the correct key was cued by a bright light. They behaved appropriately, however, on succeeding trials of other sequences. Thus, the errors were followed by trials on which reinforcement occurred. Manipulation of this contingency indicated its importance in maintaining the stereotyped error patterns.

Right and left heart failure in severe H1N1 influenza A infection

Influenza infection can affect cardiac function. The recent pandemic of H1N1 influenza A provided an opportunity to study echocardiographic findings in critically ill infected patients. We hypothesised that critically ill patients with H1N1 infection would have a higher incidence of right and left heart failure than is seen in unselected populations of patients with septic shock and/or acute respiratory distress syndrome (ARDS). We retrospectively studied all patients admitted to four intensive care units at three hospitals in Salt Lake County, UT, USA, with laboratory-confirmed H1N1 infection in whom a clinical echocardiogram was available. 23 out of 48 patients had qualifying echocardiograms. Right ventricular (RV) dilatation (50-80%) and at least moderate systolic impairment (23%) were common, higher than the range described in general populations with ARDS. Left ventricular systolic dysfunction was present in 17% of patients. No single echocardiographic parameter was associated with 28-day mortality or ventilator-free days to 28 days. Critically ill patients with H1N1 infection frequently exhibit right heart dilatation and failure. RV basal dilatation was extremely common. These patients have less left heart failure than expected on the basis of prior descriptions of influenza myopericarditis or of general populations of septic patients.

Genetic variation in components of dopamine neurotransmission impacts ventral striatal reactivity associated with impulsivity

Individual differences in traits such as impulsivity involve high reward sensitivity and are associated with risk for substance use disorders. The ventral striatum (VS) has been widely implicated in reward processing, and individual differences in its function are linked to these disorders. Dopamine (DA) plays a critical role in reward processing and is a potent neuromodulator of VS reactivity. Moreover, altered DA signaling has been associated with normal and pathological reward-related behaviors. Functional polymorphisms in DA-related genes represent an important source of variability in DA function that may subsequently impact VS reactivity and associated reward-related behaviors. Using an imaging genetics approach, we examined the modulatory effects of common, putatively functional DA-related polymorphisms on reward-related VS reactivity associated with self-reported impulsivity. Genetic variants associated with relatively increased striatal DA release (DRD2 -141C deletion) and availability (DAT1 9-repeat), as well as diminished inhibitory postsynaptic DA effects (DRD2 -141C deletion and DRD4 7-repeat), predicted 9-12% of the interindividual variability in reward-related VS reactivity. In contrast, genetic variation directly affecting DA signaling only in the prefrontal cortex (COMT Val158Met) was not associated with variability in VS reactivity. Our results highlight an important role for genetic polymorphisms affecting striatal DA neurotransmission in mediating interindividual differences in reward-related VS reactivity. They further suggest that altered VS reactivity may represent a key neurobiological pathway through which these polymorphisms contribute to variability in behavioral impulsivity and related risk for substance use disorders.

A strategy for systemic delivery of the oncolytic herpes virus HSV1716: redirected tropism by antibody-binding sites incorporated on the virion surface as a glycoprotein D fusion protein

We report on the ability of single-chain variable fragment (scFv) incorporated into the viral envelope to alter the tropism of herpes simplex virus (HSV) 1716. Using recombinant viruses expressing fusion proteins comprising cell-surface antigen-specific scFvs N terminus linked to amino acids 274-393 of gD, we demonstrated that the tropism of these HSV1716 variants was modified such that infection was mediated by the cognate antigen. Thus, an HSV1716 variant that expressed an anti-CD55 scFv targeting moiety linked to these gD residues was able to infect non-permissive Chinese hamster ovary cells expressing CD55 and this infection was specifically blocked by an anti-CD55 monoclonal antibody. Similarly, the infection efficiency of an HSV1716 variant for semi-permissive human leukaemic, CD38-positive cell lines was greatly improved by an anti-CD38 scFv targeting moiety linked to gD residues 274-393, and this enhanced infectivity was abrogated specifically by an anti-CD38 monoclonal antibody. Finally, intravenous/intraperitoneal injection of an HSV1716 variant displaying an anti-epidermal growth factor receptor (EGFR) scFv linked to residues 274-393 of gD enhanced destruction of subcutaneous EGFR-positive tumours in nude mice compared to unmodified HSV1716. Therefore, targeting of HSV1716 oncolysis to specific cell types through the display of entry mediating scFv/gD fusion proteins represents an efficient route for systemic delivery.

Cytotoxic effects of the oncolytic herpes simplex virus HSV1716 alone and in combination with cisplatin in head and neck squamous cell carcinoma

CONCLUSIONS

HSV1716 alone and combined with cisplatin was efficacious in destroying head and neck squamous cell carcinoma (HNSCC) cells. Combination treatment with HSV1716 and cisplatin gave additive efficacy. These results indicate that HSV1716 in combination with cisplatin could be of therapeutic value in HNSCC and warrants further investigation.

OBJECTIVES

HSV1716 is a replication competent herpes simplex virus which selectively replicates and lyses actively dividing cells but not normal or terminally differentiated cells. The objective of this study was to determine the efficacy of HSV1716 alone and in combination with cisplatin in HNSCC.

MATERIALS AND METHODS

Three HNSCC cell lines were studied; UM-SCC 14C, UM-SCC 22A and UM-SCC 22B. The permissivity of HSV1716 in these cell lines was determined using multicycle growth experiments. In vitro, cytotoxicity of HSV1716 and cisplatin was determined using an MTS proliferation assay. Isobologram analysis was used to determine the interaction between HSV1716 and cisplatin combination treatment.

RESULTS

The three HNSCC cell lines studied were permissive for HSV1716 replication. Cytotoxicity increased in a dose-dependent fashion in all three cell lines. Cisplatin was non-toxic to the virus. Isobologram analysis showed additive cytotoxicity when HSV1716 was combined with cisplatin in all three cell lines.

Population genomics of the immune evasion (var) genes of Plasmodium falciparum

Var genes encode the major surface antigen (PfEMP1) of the blood stages of the human malaria parasite Plasmodium falciparum. Differential expression of up to 60 diverse var genes in each parasite genome underlies immune evasion. We compared the diversity of the DBLα domain of var genes sampled from 30 parasite isolates from a malaria endemic area of Papua New Guinea (PNG) and 59 from widespread geographic origins (global). Overall, we obtained over 8,000 quality-controlled DBLα sequences. Within our sampling frame, the global population had a total of 895 distinct DBLα “types” and negligible overlap among repertoires. This indicated that var gene diversity on a global scale is so immense that many genomes would need to be sequenced to capture its true extent. In contrast, we found a much lower diversity in PNG of 185 DBLα types, with an average of approximately 7% overlap among repertoires. While we identify marked geographic structuring, nearly 40% of types identified in PNG were also found in samples from different countries showing a cosmopolitan distribution for much of the diversity. We also present evidence to suggest that recombination plays a key role in maintaining the unprecedented levels of polymorphism found in these immune evasion genes. This population genomic framework provides a cost effective molecular epidemiological tool to rapidly explore the geographic diversity of var genes.

Malaria parasites live in red blood cells of the human host for part of the life cycle, during which a family of diverse antigens known as PfEMP1 are placed on the surface. PfEMP1 variants switch by sequential expression of up to 60 var genes. This allows the parasite to evade immune detection within an individual host, enhancing its chances to be transmitted to the mosquito vector in situations where mosquitoes are seasonally available. Methods to rapidly assess var gene diversity in parasite populations are needed to measure antigenic diversity and define relationships with malaria transmission. Using a specialized framework, we completed the first systematic sampling of var genes from parasite genomes obtained from the same (Papua New Guinea [PNG]) and different (global) populations. Globally, there was no limit to the number of var genes because parasites rarely shared var genes. In PNG, var gene numbers were restricted due to high levels of sharing, and most were only found in that population. Recombination was important to the evolution of var genes in PNG. The data suggest there are distinct var genes in different populations, which may have consequences for the spread of malarial disease from one geographic area to another.

Role of peripheral hyperpolarization-activated cyclic nucleotide-modulated channel pacemaker channels in acute and chronic pain models in the rat

Hyperpolarization-activated, cyclic nucleotide-modulated (HCN) channels contribute to rhythmic spontaneous activity in the heart and CNS. Ectopic spontaneous neuronal activity has been implicated in the development and maintenance of acute and chronic hyperalgesia, allodynia and spontaneous pain. Previously, we documented that systemic administration of ZD7288, a specific blocker of pacemaker current (I(h)), decreased ectopic activity in dorsal root ganglion (DRG) and reversed tactile allodynia in spinal nerve ligated (SNL) rats [Chaplan SR, Guo HQ, Lee DH, Luo L, Liu C, Kuei C, Velumian AA, Butler MP, Brown SM, Dubin AE (2003) Neuronal hyperpolarization-activated pacemaker channels drive neuropathic pain. J Neurosci 23:1169-1178]. Spontaneous pain is the chief clinical manifestation of peripheral nerve injury; however, a role for I(h) in spontaneous pain has not been described. Here, in further rat studies, we report that systemic administration of ZD7288 reversed spontaneous pain induced by mild thermal injury (MTI) and tactile allodynia induced by SNL and MTI. In contrast, ZD7288 did not reduce thermal hyperalgesia. An important locus of action appears to be in the skin since intraplantar (local) administration of ZD7288 completely suppressed tactile allodynia arising from MTI and SNL and reduced spontaneous pain due to MTI. Immunohistochemical staining of plantar skin sections detected HCN1-HCN4 expression in mechanosensory structures (e.g., Meissner's corpuscles and Merkel cells). Collectively, these data suggest that expression and modulation of I(h) in the peripheral nervous system, including specialized sensory structures, may play a significant role in sensory processing and contribute to spontaneous pain and tactile allodynia.

Assessment of 123I-FIAU imaging of herpes simplex viral gene expression in the treatment of glioma

BACKGROUND

Herpes simplex virus 1716 (HSV1716), a selectively replication competent mutant of HSV1, is under investigation as an oncolytic viral therapy in human malignant glioma. As with similar therapies, a technique for measurement of viral replication and distribution over time following virus administration is required. Imaging expression of the HSV-thymidine kinase (HSV-tk) gene offers an opportunity for non-invasive assessment of viral distribution in living subjects. This is the first study to explore the use of HSV-tk as a reporter gene and radiolabelled thymidine analogue 5-[(123)I]iodo-1-(2-deoxy-2-fluoro-beta-D-arabinofuranosyl) uracil ((123)I-FIAU) as a marker substrate to non-invasively monitor HSV1716 replication in humans during treatment of high-grade glioma.

METHODS

I-FIAU brain SPECT imaging was undertaken in eight patients receiving intra-tumoural injection of HSV1716, before and after administration of the virus. Baseline images were acquired 3 days prior to virus administration and between 1 and 5 days following virus administration. Region of interest analysis was used to investigate whether there was an increase in (123)I-FIAU concentration following virus administration due to HSV-tk expression.

RESULT

Increased (123)I-FIAU accumulation due to HSV-tk expression was not detected in this study. The possible explanations for this finding are explored and design options for future studies are discussed.

Modified virtual reality technology for treatment of amblyopia

PURPOSE

The conventional patching/occlusion treatment for amblyopia sometimes gives disappointing results for a number of reasons: it is unpopular, prolonged, frequently resulting in poor or noncompliance, and also disrupts fusion. The aim of this research was to develop a novel virtual-reality (VR)-based display system that facilitates the treatment of amblyopia with both eyes stimulated simultaneously.

METHODS

We have adopted a multidisciplinary approach, combining VR expertise with a team of ophthalmologists and orthoptists to develop the Interactive Binocular Treatment (I-BiT) system. This system incorporates adapted VR technology and specially written software providing interactive 2D and 3D games and videos to the patient via a stereo (binocular) display, and a control screen for the clinician.

RESULTS

We developed a prototype research system designed for treatment of amblyopia in children.

CONCLUSIONS

The result is a novel way to treat amblyopia, which allows binocular treatment. It is interactive, and as it is partially software based, can be adapted to suit the age/ability, and needs of the patient. This means that the treatment can be made captivating and enjoyable. Further research is on-going to determine the efficacy of this new modality in the treatment of amblyopia.

Preliminary results from the use of the novel Interactive binocular treatment (I-BiT) system, in the treatment of strabismic and anisometropic amblyopia

BACKGROUND

We have developed a novel application of adapted virtual reality (VR) technology, for the binocular treatment of amblyopia. We describe the use of the system in six children.

METHODS

Subjects consisted of three conventional treatment 'failures' and three conventional treatment 'refusers', with a mean age of 6.25 years (5.42-7.75 years). Treatment consisted of watching video clips and playing interactive games with specifically designed software to allow streamed binocular image presentation.

RESULTS

Initial vision in the amblyopic eye ranged from 6/12 to 6/120 and post-treatment 6/7.5 to 6/24-1. Total treatment time was a mean of 4.4 h. Five out of six children have shown an improvement in their vision (average increase of 10 letters), including those who had previously failed to comply with conventional occlusion.

CONCLUSIONS

Improvements in vision were demonstrable within a short period of time, in some children after 1 h of treatment. This system is an exciting and promising application of VR technology as a new treatment for amblyopia.

Identification of the growth arrest and DNA damage protein GADD34 in the normal human heart and demonstration of alterations in expression following myocardial ischaemia

Growth arrest and DNA damage protein 34 (GADD34) is a multifunctional protein upregulated in response to cellular stress and is believed to mediate DNA repair and restore protein synthesis. In the present study we have examined GADD34 immunoreactivity in human myocardial tissue at defined survival times following cardiac arrest and determined alterations in expression following ischaemia. In the normal human heart, GADD34 immunoreactivity was generally intense and present within most cells. GADD34 immunoreactivity was downregulated in tissue displaying ischaemic damage and remained intense in adjacent non-infarcted tissue. Unlike brain, GADD34 was not found to be upregulated in the peri-infarct zone. Cells displaying apoptotic changes were located in regions displaying reduced GADD34 immunoreactivity. In the brain, it is thought that GADD34 supports re-initiation of protein synthesis following ischaemia. Similarly, GADD34 may perform important functions in cardiac tissue in response to ischaemia.

A regulatory variant of the human tryptophan hydroxylase-2 gene biases amygdala reactivity

Recent studies have indicated that a newly identified second isoform of the tryptophan hydroxylase gene (TPH2) is preferentially involved in the rate-limiting synthesis of neuronal serotonin. Genetic variation in the human TPH2 gene (hTPH2) has been associated with altered in vitro enzyme activity as well as increased risk for mood disorders. Here, we provide the first in vivo evidence that a relatively frequent regulatory variant (G(-844)T) of hTPH2 biases the reactivity of the amygdala, a neural structure critical in the generation and regulation of emotional behaviors.

Assessment In Vitro of a Novel Therapeutic Strategy for Glioma, Combining Herpes Simplex Virus HSV1716-mediated Oncolysis with Gene Transfer and Targeted Radiotherapy

Genetically engineered herpes simplex virus ICP34.5 null mutants replicate only in dividing cells and have shown potential for the treatment of malignant disease, including glioma. Phase I trials have demonstrated the safety of these viruses in various clinical settings but it is envisaged that for full efficacy they will be used in combination with other therapeutic modalities. To enhance virus-induced tumour cytotoxicity, we have engineered an ICP34.5 null mutant (HSV1716) of HSV1 which expresses the noradrenaline transporter gene (NAT). This virus is designated HSV1716/NAT. We have shown previously that introduction of the NAT gene into a range of tumour cells, via plasmid-mediated transfection, conferred the capacity for active uptake of the radiopharmaceutical [131I]MIBG and resulted in dose-dependent toxicity. In this study, combination therapy utilising HSV1716/NAT and [131I]MIBG was assessed in vitro by the MTT assay. We demonstrate that the NAT gene, introduced by HSV1716/NAT into cultured glioma cells, was expressed 1 h after viral infection, enabling active uptake of [131I]MIBG. The combination of viral oncolysis and induced radiopharmaceutical uptake resulted in significantly enhanced cytotoxicity compared to either agent alone and the response was dose- and time-dependent. These studies show that the combination of oncolytic HSV therapy with targeted radiotherapy has the potential for effective tumour cell kill and warrants further investigation as a treatment for malignant glioma.

HSV1716 injection into the brain adjacent to tumour following surgical resection of high-grade glioma: safety data and long-term survival

Following standard treatment, the prognosis remains poor in patients with high-grade glioma and new therapies are urgently required. Herpes simplex virus 1716 (HSV1716) is an ICP34.5 null mutant that is selectively replication competent and shown to be safe and to replicate following injection into high-grade glioma. We demonstrate that following surgical resection, HSV1716 is safe when injected into the brain adjacent to excised tumour. In all, 12 patients with recurrent or newly diagnosed high-grade glioma underwent maximal resection of the tumour. HSV1716 was injected into eight to 10 sites around the resulting tumour cavity with the intent of infecting residual tumour cells. As clinically indicated, patients proceeded to further radiotherapy or chemotherapy. There has been no clinical evidence of toxicity associated with the administration of HSV1716. Longitudinal follow-up has allowed the assessment of overall survival compared to that of similar patients not treated with HSV1716. Three patients remain alive and clinically stable at 15, 18 and 22 months postsurgery and HSV1716 injection. Remarkably, the first patient in the trial, who had extensive recurrent disease preprocedure, is alive at 22 months since injection of HSV1716 and 29 months since first diagnosis. Imaging has demonstrated a reduction of residual tumour over the 22-month period despite no further medical intervention since the surgery and HSV1716 injection. In this study, we demonstrate that on the basis of clinical observations, there has been no toxicity following the administration of HSV1716 into the resection cavity rim in patients with high-grade glioma. The survival and imaging data, in addition to the lack of toxicity, give us confidence to proceed to a clinical trial to demonstrate efficacy of HSV1716 in glioma patients.

Eyeblink conditioning deficits indicate timing and cerebellar abnormalities in schizophrenia

Accumulating evidence indicates that individuals with schizophrenia manifest abnormalities in structures (cerebellum and basal ganglia) and neurotransmitter systems (dopamine) linked to internal-timing processes. A single-cue tone delay eyeblink conditioning paradigm comprised of 100 learning and 50 extinction trials was used to examine cerebellar timing circuits in 13 medicated patients with schizophrenia and 13 age- and sex-matched controls. Patients with schizophrenia showed impaired learning of the conditioned response compared to controls and also greater within-subject variability in the timing of their responses. These findings are consistent with models of schizophrenia in which timing deficits underlie information-processing abnormalities and clinical features of the disorder.

Up-regulation of a growth arrest and DNA damage protein (GADD34) in the ischaemic human brain: implications for protein synthesis regulation and DNA repair

GADD34 is a growth arrest and DNA damage inducible gene up-regulated in response to DNA damage, cell cycle arrest and apoptosis. It is thought that GADD34 may play a crucial role in cell survival in ischaemia. GADD34 expression was assessed immunohistochemically in post-mortem human hippocampal tissue obtained from patients surviving for defined periods (0-24 h; 24 h-7 days) after a cardiac arrest and in age-matched control subjects. In control brain, cytoplasm staining in GADD34 immunopositive cells was faint but present throughout the hippocampus and cortex. There was minimal change in GADD34 expression in the group surviving 0-24 h after cardiac arrest. However GADD34 immunostaining was markedly increased in selectively vulnerable regions in the 24 h-7 day survival group. Increased GADD34 staining was present in ischaemic neurones and in some morphologically normal neurones after cardiac arrest. Extensive ischaemic damage was found to correlate with elevated GADD34 immunostaining in the CA1 layer of the hippocampus (**P < 0.0016). In addition, GADD34 was found to colocalize with proliferating cell nuclear antigen in some neurones. The up-regulation of GADD34 in response to global ischaemia in the human brain plus its influence on protein synthesis and DNA repair suggests that this protein may have the potential to influence cell survival.

Selection and validation of differentially expressed genes in head and neck cancer

We applied a robust combinatorial (multi-test) approach to microarray data to identify genes consistently up- or down-regulated in head and neck squamous cell carcinoma (HNSCC). RNA was extracted from 22 paired samples of HNSCC and normal tissue from the same donors and hybridized to the Affymetrix U95A chip. Forty-two differentially expressed probe sets (representing 38 genes and one expressed sequence tag) satisfied all statistical tests of significance and were selected for further validation. Selected probe sets were validated by hierarchical clustering, multiple probe set concordance, and target-subunit agreement. In addition, real-time PCR analysis of 8 representative (randomly selected from 38) genes performed on both microarray-tested and independently obtained samples correlated well with the microarray data. The genes identified and validated by this method were in comparatively good agreement with other rigorous HNSCC microarray studies. From this study, we conclude that combinatorial analysis of microarray data is a promising technique for identifying differentially expressed genes with few false positives.

HSV Growth, Preparation, and Assay

Whether herpes simplex virus (HSV) is viewed as a pathogen or as a model eukaryotic system, it is virtually certain that any experimental work will require the virus to be grown and assayed. The following chapter is therefore seen as the fundamental first step before embarking on more intellectually and technically challenging technology. Its importance should not however be underestimated. It never fails to surprize us that people who describe themselves as virologists have little understanding of the basic requirements needed to attain a contamination-free, high-titer, low particle:plaque-forming units (PFU) ratio, genetically pure virus stock.

Atopic dermatitis: a new treatment paradigm using pimecrolimus

Atopic dermatitis (AD), often called eczema, is a disease characterized by intense pruritus, erythema, dry skin, and inflammation. Pimecrolimus is a novel steroid-free treatment for AD. Consistently positive results have been found with pimecrolimus treatment in infants, children/adolescents, and adults. Its safety record is excellent, and studies have found no clinically relevant drug-related systemic adverse events. In this article, we first review atopic dermatitis and conventional treatment strategies. We then discuss various aspects of pimecrolimus, including pharmacologic properties, toxicology, short- and long-term studies, and safety and adverse events. Finally, we propose a new steroid-sparing treatment strategy for AD.

Genomics-based identification of self-ligands with T cell receptor-specific biological activity

Self-peptide/major histocompatibility complex (MHC) complexes profoundly influence the biology of T lymphocytes. They promote the selection of the T cell receptor (TCR) repertoire in the thymus, maintain the homeostasis of peripheral T cells prior to encounter with antigen, and modify the responsiveness of T cells to foreign antigens. In addition, they can serve as antigens for autoaggressive T cells that induce autoimmune diseases. The complete sequencing of the genomes of human, mouse, and many pathogenic organisms now provides us with a comprehensive list of all possible proteins that may be the source of foreign antigenic and self-peptides. A computational approach using profile-based similarity searches on potential self-MHC-binding peptides can be used to efficiently predict self-peptides with biological activities. The common feature of the identified peptides is similarity to antigen. Thus, self-peptides may form 'hazy' images of the universe of antigens that are used as templates to create and maintain the TCR repertoire.

Infectivity-associated changes in the transcriptional repertoire of the malaria parasite sporozoite stage

Injection of Plasmodium salivary gland sporozoites into the vertebrate host by Anopheles mosquitoes initiates malaria infection. Sporozoites develop within oocysts in the mosquito midgut and then enter and mature in the salivary glands. Although morphologically similar, oocyst sporozoites and salivary gland sporozoites differ strikingly in their infectivity to the mammalian host, ability to elicit protective immune responses, and cell motility. Here, we show that differential gene expression coincides with these dramatic phenotypic differences. Using suppression subtractive cDNA hybridization we identified highly up-regulated mRNAs transcribed from 30 distinct genes in salivary gland sporozoites. Of those genes, 29 are not significantly expressed in the parasite's blood stages. The most frequently recovered transcript encodes a protein kinase. Developmental up-regulation of specific mRNAs in the infectious transmission stage of Plasmodium indicates that their translation products may have unique roles in hepatocyte infection and/or development of liver stages.

HSV1716 persistence in primary human glioma cells in vitro

HSV1716 is a selectively replication competent mutant of herpes simplex virus which is in trial in glioma patients. We have demonstrated that HSV1716 is non-toxic when delivered into tumour or into brain adjacent to tumour, yet replicates within tumour cells. Tumour tissue, from one patient treated 2.5 years previously with intra-tumoural HSV1716, was put into culture. The cultured cells were shown to be glial in origin with no evidence of residual HSV1716. These cells were subsequently infected at a MOI of 0.1 with either HSV1716 or wild-type HSV17(+). The HSV17(+) infected cells were completely rounded up or lysed within 72 h. Although the cells supported HSV1716 replication and also became rounded or lysed, a proportion (approximately 20%) remained viable. These cells continued to divide and shed low levels of HSV1716 up to 31 days after infection when there was evidence of rapid virus replication resulting in complete cell lysis. These data demonstrate that HSV1716 can 'persist' in human glioma cells at least in vitro and gives credence to the possibility that in tumours in vivo a similar phenomenon may take place. If this were the case, then HSV1716 has the potential to kill tumour cells over a prolonged period of time.

Rare, structurally homologous self-peptides promote thymocyte positive selection

Although it is clear that positive selection of T cells involves recognition of specific self-peptide/MHC complexes, the nature of these self-ligands and their relationship to the cognate antigen are controversial. Here we used two complementary strategies to identify naturally occurring self-peptides able to induce positive selection of T cells bearing a specific T cell receptor, OT-I. Both the bioassay- and bioinformatics-based strategies identified the same self-peptides, derived from F-actin capping protein and beta-catenin. These peptides displayed charge conservation at two key TCR contact residues. The biological activity of 43 other self-peptides and of complex peptide libraries directly correlated to the extent of conservation at TCR contact residues. These results demonstrate that selecting self-peptides are rare and can be identified by homology-based search strategies.

Specific expression of the cell cycle regulation proteins, GADD34 and PCNA, in the peri-infarct zone after focal cerebral ischaemia in the rat

Cell cycle proteins play key roles in cell survival or death under pathological conditions. Expression of growth arrest and DNA damage-inducible protein, GADD34 and proliferating cell nuclear antigen (PCNA) have been investigated in the core and peri-infarct zone at 2 and 24 h after middle cerebral artery occlusion (MCAO). At these times after MCAO, numerous GADD34-positive cells were present, particularly in the peri-infarct zone (e.g. 24 +/- 4 and 52 +/- 6 immunopositive cells/0.25 mm2 at 2 and 24 h, respectively, in cortex). PCNA-immunopositive cells were barely detectable in the peri-infarct zone at 2 h; however, numerous PCNA-immunopositive cells were present in this zone by 24 h (0.7 +/- 0.3 and 10.6 +/- 1.5 immunopositive cells/0.25 mm2, respectively) as well as in the adjacent cortex and in the contralateral cingulate cortex. Most GADD34-immunopositive cells coexpressed the neuronal marker Neu-N with a smaller number coexpressing the microglial marker, Mrf-1. Evidence of morphologically 'abnormal' and 'normal' GADD34 immunopositive neurons was found within the peri-infarct zone. The majority of PCNA immunopositive cells were Mrf-1 positive with a smaller number Neu-N positive. Double-labelling revealed colocalization of GADD34 and PCNA in some cells within the peri-infarct zone and in the ependymal cells lining the ventricles. The presence of GADD34 and PCNA in a key anatomical location pertinent to the evolving ischaemic lesion indicates that GADD34, either alone or in combination with PCNA, has the potential to influence cell survival in ischaemically compromised tissue.

Scaling laws in NMR scattering via dipolar fields

Breaking translational symmetry in magnetostatics imparts a scale dependence that is commonly investigated in physics (W. Warren et al., 1993, Science 262, 2005-2008). An interesting and important example arises in nuclear magnetic resonance studies involving the dipolar mean field of adjacent nuclear spins where the scattering (transfer of spatial spin gratings) via intermolecular macroscopic fields carries a signature of the local spatial distribution of the spin density. For arbitrary geometry, the inverse problem of extracting this spin distribution from experiments is intractable. Here we point out a simple, universal crossover in the scaling behavior at the sample's characteristic length scale, xi, of the species fluctuations in the sample along the measurement direction. This behavior is observed experimentally in an oil-water emulsion, an important representation of complex, heterogeneous, soft matter.