Viral co-infection, autoimmunity, and CSF HIV antibody profiles in HIV central nervous system escape

Antiretroviral therapy (ART) suppresses plasma and cerebrospinal fluid (CSF) HIV replication. Neurosymptomatic (NS) CSF escape is a rare exception in which CNS HIV replication occurs in the setting of neurologic impairment. The origins of NS escape are not fully understood. We performed a case-control study of asymptomatic (AS) escape and NS escape subjects with HIV-negative subjects as controls in which we investigated differential immunoreactivity to self-antigens in the CSF of NS escape by employing neuroanatomic CSF immunostaining and massively multiplexed self-antigen serology (PhIP-Seq). Additionally, we utilized pan-viral serology (VirScan) to deeply profile the CSF anti-viral antibody response and metagenomic next-generation sequencing (mNGS) for pathogen detection. We detected Epstein-Barr virus (EBV) DNA more frequently in the CSF of NS escape subjects than in AS escape subjects. Based on immunostaining and PhIP-Seq, there was evidence for increased immunoreactivity against self-antigens in NS escape CSF. Finally, VirScan revealed several immunodominant epitopes that map to the HIV envelope and gag proteins in the CSF of AS and NS escape subjects. Whether these additional inflammatory markers are byproducts of an HIV-driven process or whether they independently contribute to the neuropathogenesis of NS escape will require further study.

A Rare Bird: Diagnosis of Psittacosis Meningitis by Clinical Metagenomic Next-Generation Sequencing

Psittacosis is a zoonotic infectious disease caused by the transmission of Chlamydia psittaci; it often presents as a pulmonary infection but rarely as disseminated disease. Because diagnoses of psittacosis are often underreported due to infrequent pathogen-specific testing, clinical metagenomic next-generation sequencing may be helpful to diagnose such an uncommon syndrome.

Neurite Orientation Dispersion and Density Imaging for Assessing Acute Inflammation and Lesion Evolution in MS

BACKGROUND AND PURPOSE

MR imaging is essential for MS diagnosis and management, yet it has limitations in assessing axonal damage and remyelination. Gadolinium-based contrast agents add value by pinpointing acute inflammation and blood-brain barrier leakage, but with drawbacks in safety and cost. Neurite orientation dispersion and density imaging (NODDI) assesses microstructural features of neurites contributing to diffusion imaging signals. This approach may resolve the components of MS pathology, overcoming conventional MR imaging limitations.

MATERIALS AND METHODS

Twenty-one subjects with MS underwent serial enhanced MRIs (12.6 ± 9 months apart) including NODDI, whose key metrics are the neurite density and orientation dispersion index. Twenty-one age- and sex-matched healthy controls underwent unenhanced MR imaging with the same protocol. Fifty-eight gadolinium-enhancing and non-gadolinium-enhancing lesions were semiautomatically segmented at baseline and follow-up. Normal-appearing WM masks were generated by subtracting lesions and dirty-appearing WM from the whole WM.

RESULTS

The orientation dispersion index was higher in gadolinium-enhancing compared with non-gadolinium-enhancing lesions; logistic regression indicated discrimination, with an area under the curve of 0.73. At follow-up, in the 58 previously enhancing lesions, we identified 2 subgroups based on the neurite density index change across time: Type 1 lesions showed increased neurite density values, whereas type 2 lesions showed decreased values. Type 1 lesions showed greater reduction in size with time compared with type 2 lesions.

CONCLUSIONS

NODDI is a promising tool with the potential to detect acute MS inflammation. The observed heterogeneity among lesions may correspond to gradients in severity and clinical recovery after the acute phase.

Visual attention, EEG alpha power and T7-Fz connectivity are implicated in prosthetic hand control and can be optimized through gaze training

Background

Prosthetic hands impose a high cognitive burden on the user that often results in fatigue, frustration and prosthesis rejection. However, efforts to directly measure this burden are sparse and little is known about the mechanisms behind it. There is also a lack of evidence-based training interventions designed to improve prosthesis hand control and reduce the mental effort required to use them. In two experiments, we provide the first direct evaluation of this cognitive burden using measurements of EEG and eye-tracking (Experiment 1), and then explore how a novel visuomotor intervention (gaze training; GT) might alleviate it (Experiment 2).

Methods

In Experiment 1, able-bodied participants (n = 20) lifted and moved a jar, first using their anatomical hand and then using a myoelectric prosthetic hand simulator. In experiment 2, a GT group (n = 12) and a movement training (MT) group (n = 12) trained with the prosthetic hand simulator over three one hour sessions in a picking up coins task, before returning for retention, delayed retention and transfer tests. The GT group received instruction regarding how to use their eyes effectively, while the MT group received movement-related instruction typical in rehabilitation.

Results

Experiment 1 revealed that when using the prosthetic hand, participants performed worse, exhibited spatial and temporal disruptions to visual attention, and exhibited a global decrease in EEG alpha power (8-12 Hz), suggesting increased cognitive effort. Experiment 2 showed that GT was the more effective method for expediting prosthesis learning, optimising visual attention, and lowering conscious control – as indexed by reduced T7-Fz connectivity. Whilst the MT group improved performance, they did not reduce hand-focused visual attention and showed increased conscious movement control. The superior benefits of GT transferred to a more complex tea-making task.

Conclusions

These experiments quantify the visual and cortical mechanisms relating to the cognitive burden experienced during prosthetic hand control. They also evidence the efficacy of a GT intervention that alleviated this burden and promoted better learning and transfer, compared to typical rehabilitation instructions. These findings have theoretical and practical implications for prosthesis rehabilitation, the development of emerging prosthesis technologies and for the general understanding of human-tool interactions.

Electronic supplementary material

The online version of this article (10.1186/s12984-019-0524-x) contains supplementary material, which is available to authorized users.

Action observation for sensorimotor learning in surgery

Background

Acquiring new motor skills to learn complex movements and master the use of a diverse range of instruments is fundamental for developing expertise in surgery. Although aspects of skill development occur through trial and error, watching the performance of another individual (action observation) is an increasingly important adjunct for the acquisition of these complex skills before performing a procedure. The aim of this review was to examine the evidence in support of the use of action observation in surgery.

Methods

A narrative review of observational learning for surgical motor skills was undertaken. Searches of PubMed and PsycINFO databases were performed using the terms ‘observational learning’ OR ‘action observation’ AND ‘motor learning’ OR ‘skill learning’.

Results

Factors such as the structure of physical practice, the skill level of the demonstrator and the use of feedback were all found to be important moderators of the effectiveness of observational learning. In particular, observation of both expert and novice performance, cueing attention to key features of the task, and watching the eye movements of expert surgeons were all found to enhance the effectiveness of observation. It was unclear, however, whether repeated observations were beneficial for skill learning. The evidence suggests that these methods can be employed to enhance surgical training curricula.

Conclusion

Observational learning is an effective method for learning surgical skills. An improved understanding of observational learning may further inform the refinement and use of these methods in contemporary surgical training curricula.

Acute West Nile Virus Meningoencephalitis Diagnosed Via Metagenomic Deep Sequencing of Cerebrospinal Fluid in a Renal Transplant Patient

Solid organ transplant patients are vulnerable to suffering neurologic complications from a wide array of viral infections and can be sentinels in the population who are first to get serious complications from emerging infections like the recent waves of arboviruses, including West Nile virus, Chikungunya virus, Zika virus, and Dengue virus. The diverse and rapidly changing landscape of possible causes of viral encephalitis poses great challenges for traditional candidate-based infectious disease diagnostics that already fail to identify a causative pathogen in approximately 50% of encephalitis cases. We present the case of a 14-year-old girl on immunosuppression for a renal transplant who presented with acute meningoencephalitis. Traditional diagnostics failed to identify an etiology. RNA extracted from her cerebrospinal fluid was subjected to unbiased metagenomic deep sequencing, enhanced with the use of a Cas9-based technique for host depletion. This analysis identified West Nile virus (WNV). Convalescent serum serologies subsequently confirmed WNV seroconversion. These results support a clear clinical role for metagenomic deep sequencing in the setting of suspected viral encephalitis, especially in the context of the high-risk transplant patient population.

Abstract P1-10-14: Early results of toxicity for high-risk patients treated with hypofractionated regional nodal irradiation

This abstract was withdrawn by the authors.

Sulfate-reducing bacteria slow intestinal transit in a bismuth-reversible fashion in mice

BACKGROUND

Hydrogen sulfide (H₂ S) serves as a mammalian cell-derived gaseous neurotransmitter. The intestines are exposed to a second source of this gas by sulfate-reducing bacteria (SRB). Bismuth subsalicylate binds H₂ S rendering it insoluble. The aim of this study was to test the hypothesis that SRB may slow intestinal transit in a bismuth-reversible fashion.

METHODS

Eighty mice were randomized to five groups consisting of Live SRB, Killed SRB, SRB+Bismuth, Bismuth, and Saline. Desulfovibrio vulgaris, a common strain of SRB, was administered by gavage at the dose of 1.0 × 10⁹ cells along with rhodamine, a fluorescent dye. Intestinal transit was measured 50 minutes after gavage by euthanizing the animals, removing the small intestine between the pyloric sphincter and the ileocecal valve and visualizing the distribution of rhodamine across the intestine using an imaging system (IVIS, Perkin-Elmer). Intestinal transit (n=50) was compared using geometric center (1=minimal movement, 100=maximal movement). H₂ S concentration (n=30) was also measured when small intestinal luminal content was allowed to generate this gas.

KEY RESULTS

The Live SRB group had slower intestinal transit as represented by a geometric center score of 40.2 ± 5.7 when compared to Saline: 73.6 ± 5.7, Killed SRB: 77.9 ± 6.9, SRB+Bismuth: 81.0 ± 2.0, and Bismuth: 73.3 ± 4.2 (P<.0001). Correspondingly, the Live SRB group had the highest luminal H₂ S concentration of 4181.0 ± 968.0 ppb compared to 0 ± 0 ppb for the SRB+Bismuth group (P<.0001).

CONCLUSIONS & INFERENCES

Live SRB slow intestinal transit in a bismuth-reversible fashion in mice. Our results demonstrate that intestinal transit is slowed by SRB and this effect could be abolished by H₂ S-binding bismuth.

Molecular dynamics simulations of the structure and the morphology of graphene/polymer nanocomposites

Molecular dynamics simulations are performed to scrutinize the structure and morphology of three polymer/graphene nanocomposites.

Alpha-2 macroglobulin in Alzheimer's disease: a marker of neuronal injury through the RCAN1 pathway

Preclinical changes that precede the onset of symptoms and eventual diagnosis of Alzheimer's disease (AD) are a target for potential preventive interventions. A large body of evidence suggests that inflammation is closely associated with AD pathogenesis and may be a promising target pathway for such interventions. However, little is known about the association between systemic inflammation and preclinical AD pathophysiology. We first examined whether the acute-phase protein, alpha-2 macroglobulin (A2M), a major component of the innate immune system, was associated with cerebrospinal fluid (CSF) markers of neuronal injury in preclinical AD and risk of incident AD in the predictors of cognitive decline among normal individuals (BIOCARD) cohort. We find that A2M concentration in blood is significantly associated with CSF concentrations of the neuronal injury markers, tau and phosphorylated tau, and that higher baseline serum A2M concentration is associated with an almost threefold greater risk of progression to clinical symptoms of AD in men. These findings were replicated in the Alzheimer's Disease Neuroimaging (ADNI) study. Then, utilizing a systems level approach combining large multi-tissue gene expression datasets with mass spectrometry-based proteomic analyses of brain tissue, we identified an A2M gene network that includes regulator of calcineurin (RCAN1), an inhibitor of calcineurin, a well-characterized tau phosphatase. A2M gene and protein expression in the brain were significantly associated with gene and protein expression levels of calcineurin. Collectively these novel findings suggest that A2M is associated with preclinical AD, reflects early neuronal injury in the disease course and may be responsive to tau phosphorylation in the brain through the RCAN1-calcineurin pathway.

Paraorosius, a new genus of leafhopper (Hemiptera: Cicadellidae: <br />Deltocephalinae: Opsiini), with description of a new species from the Middle East

A new genus, of the leafhopper tribe Opsiini, Paraorosius is proposed to accommodate Orosius minuicus Dlabola, 1979 and, P. hanii sp. n. from the Kingdom of Saudi Arabia. A key to the genera of Opsiini of the Arabian Peninsula is provided.

Rapid flow cytometric measurement of protein inclusions and nuclear trafficking

Proteinaceous cytoplasmic inclusions are an indicator of dysfunction in normal cellular proteostasis and a hallmark of many neurodegenerative diseases. We describe a simple and rapid new flow cytometry-based method to enumerate, characterise and, if desired, physically recover protein inclusions from cells. This technique can analyse and resolve a broad variety of inclusions differing in both size and protein composition, making it applicable to essentially any model of intracellular protein aggregation. The method also allows rapid quantification of the nuclear trafficking of fluorescently labelled molecules.

Movement specific reinvestment and allocation of attention by older adults during walking

Older repeat fallers have previously been shown to have a higher propensity to consciously monitor and control their movements (i.e. reinvestment) than non-fallers, yet to direct their attention equally between their limb movements and the external environment during locomotion (Wong et al. in J Am Geriatr Soc 57: 920-922, 2009). Whether increased attention to their movements is a result of falling or originates from a prior inclination to reinvest remains unclear. In order to better understand the interaction between reinvestment and attention during locomotion, this study examined the allocation of attention by older adults who had not fallen but displayed a high or low inclination for reinvestment. Twenty-eight low and twenty-eight high reinvestors were required to perform 30 walking trials. Their allocation of attention during walking was evaluated by asking tone-related attentional focus questions shortly after finishing each walking trial. High reinvestors were found to be more aware of their limb movements and less aware of the external environment. Low reinvestors, on the contrary, were more aware of the surrounding environment and less aware of their movement mechanics. Given that focusing internally to body movements has been proposed to utilise working memory capacity, the ability of high reinvestors to pick up all the environmental information necessary for successful locomotion might be compromised and requires further examination.

Depletion of Abundant Sequences by Hybridization (DASH): using Cas9 to remove unwanted high-abundance species in sequencing libraries and molecular counting applications

Next-generation sequencing has generated a need for a broadly applicable method to remove unwanted high-abundance species prior to sequencing. We introduce DASH (Depletion of Abundant Sequences by Hybridization). Sequencing libraries are 'DASHed' with recombinant Cas9 protein complexed with a library of guide RNAs targeting unwanted species for cleavage, thus preventing them from consuming sequencing space. We demonstrate a more than 99 % reduction of mitochondrial rRNA in HeLa cells, and enrichment of pathogen sequences in patient samples. We also demonstrate an application of DASH in cancer. This simple method can be adapted for any sample type and increases sequencing yield without additional cost.

The impacts of larval density and protease inhibition on feeding in medicinal larvae of the greenbottle fly Lucilia sericata

Larval therapy, the therapeutic use of blowfly larvae to treat chronic wounds, is primarily used in debridement. There are, however, gaps in current knowledge of the optimal clinical application of the therapy and mechanisms of action in the debridement process. Using an artificial assay, two studies were undertaken to investigate these aspects of larval debridement by Lucilia sericata Meigen (Diptera: Calliphoridae); the first studied the effects of the density of larvae on tissue digestion and larval mass, and the second considered the effects on the same parameters of incorporating protease inhibitors into the feeding substrate. The total mass of tissue digested increased with larval density until saturation was observed at 5.0-7.5 larvae/cm(2) . This range was considered optimal as lower doses resulted in the removal of less tissue and higher doses offered no additional tissue removal and appeared to exacerbate competition for feeding. In the second study, increased protease inhibitor concentration led to significant decreases in tissue digestion and larval mass, suggesting that serine proteases, particularly trypsin, may play major roles in larval digestion. Such information is important in elucidating the main constituents that make up larval digestive products and may be significant in the development of new therapies.

Quiet eye training facilitates visuomotor coordination in children with developmental coordination disorder

INTRODUCTION

Quiet eye training (QET) has been shown to be more effective than traditional training (TT) methods for teaching a throw and catch task to typically developing 8-10 yr old children. The current study aimed to apply the technique to children with developmental coordination disorder (DCD).

METHOD

30 children with DCD were randomly allocated into TT or QET intervention groups. The TT group were taught how to control their arm movements during the throw and catch phases, while the QET group were also taught to fixate a target location on the wall prior to the throw (quiet eye1; QE1), followed by tracking the ball prior to the catch (quiet eye2; QE2). Performance, gaze and motion analysis data were collected at pre/post-training and 6-week retention.

RESULTS

The QET group significantly increased QE durations from pre-training to delayed retention (QE1 = +247 ms, QE2 = +19%) whereas the TT group experienced a reduction (QE1 = -74 ms, QE2 = -4%). QET participants showed significant improvement in the quality of their catch attempts and increased elbow flexion at catch compared to the TT group (QET = -28°, TT = -1°).

CONCLUSION

QET changed DCD children's ability to focus on a target on the wall prior to the throw, followed by better anticipation and pursuit tracking on the ball, which in turn led to improved catching technique. QET may be an effective adjunct to traditional instructions, for therapists teaching visuomotor skills to children with DCD.

Case definitions, diagnostic algorithms, and priorities in encephalitis: consensus statement of the international encephalitis consortium

BACKGROUND

Encephalitis continues to result in substantial morbidity and mortality worldwide. Advances in diagnosis and management have been limited, in part, by a lack of consensus on case definitions, standardized diagnostic approaches, and priorities for research.

METHODS

In March 2012, the International Encephalitis Consortium, a committee begun in 2010 with members worldwide, held a meeting in Atlanta to discuss recent advances in encephalitis and to set priorities for future study.

RESULTS

We present a consensus document that proposes a standardized case definition and diagnostic guidelines for evaluation of adults and children with suspected encephalitis. In addition, areas of research priority, including host genetics and selected emerging infections, are discussed.

CONCLUSIONS

We anticipate that this document, representing a synthesis of our discussions and supported by literature, will serve as a practical aid to clinicians evaluating patients with suspected encephalitis and will identify key areas and approaches to advance our knowledge of encephalitis.

Allostery without conformation change: modelling protein dynamics at multiple scales

The original ideas of Cooper and Dryden, that allosteric signalling can be induced between distant binding sites on proteins without any change in mean structural conformation, has proved to be a remarkably prescient insight into the rich structure of protein dynamics. It represents an alternative to the celebrated Monod-Wyman-Changeux mechanism and proposes that modulation of the amplitude of thermal fluctuations around a mean structure, rather than shifts in the structure itself, give rise to allostery in ligand binding. In a complementary approach to experiments on real proteins, here we take a theoretical route to identify the necessary structural components of this mechanism. By reviewing and extending an approach that moves from very coarse-grained to more detailed models, we show that, a fundamental requirement for a body supporting fluctuation-induced allostery is a strongly inhomogeneous elastic modulus. This requirement is reflected in many real proteins, where a good approximation of the elastic structure maps strongly coherent domains onto rigid blocks connected by more flexible interface regions.

Inflammatory mechanisms of ventilator-induced lung injury: a time to stop and think?

Ventilator-induced lung injury (VILI) is the phenomenon by which mechanical ventilation exacerbates lung injury in critically ill patients. It is particularly relevant for those suffering from acute respiratory distress syndrome, in which the iatrogenic injury caused by VILI contributes to their high mortality. The innate immune system is widely accepted to play an important role during VILI. However, it is our belief that the identification of inflammatory mediators that are crucial during VILI, and thus may make useful therapeutic targets, has become obscured by the wide variety of pre-clinical animal models of VILI reported in the literature. We aim here to summarise some of our work addressing this issue over the last 10 years, and thus, we hope, make interpretation of a convoluted field a little clearer.

Neural co-activation as a yardstick of implicit motor learning and the propensity for conscious control of movement

Two studies examined EEG co-activation (coherence) between the verbal-analytical (T3) and motor planning (Fz) regions during a golf putting task. In Study 1, participants with a strong propensity to consciously monitor and control their movements, determined psychometrically by high scores on a movement specific Reinvestment Scale, displayed more alpha2 T3-Fz co-activation than participants with a weak propensity. In Study 2, participants who practiced a golf putting task implicitly (via an errorless learning protocol) displayed less alpha2 T3-Fz co-activation than those who practiced explicitly (by errorful learning). In addition, explicit but not implicit motor learners displayed more T3-Fz co-activation during golf putting under pressure, implying that verbal-analytical processing of putting movements increased under pressure. These findings provide neuropsychological evidence that supports claims that implicit motor learning can be used to limit movement specific reinvestment.

Electron paramagnetic resonance spectra simulation directly from molecular dynamics trajectories of a liquid crystal with a doped paramagnetic spin probe

We report simulation of EPR spectra directly and entirely from trajectories generated from molecular dynamics simulations. Results are reported for a model 3beta-DOXYL-5alpha-cholestane spin probe in a coarse-grained solvent representing a 5CB nematic host. The results are in excellent agreement with the experimental spectra. The calculated order parameters associated with the paramagnetic probe show strong correlation with the order parameter of 5CB mesogens and are in agreement with those reported in the literature. Simulation of EPR spectra entirely from molecular dynamics of real structures provides direct correlation between molecular motions and the features observed in the spectra, allowing unambiguous interpretation of the spectra. This method opens the possibility for "computer engineering" of spin-labeled materials with the desired properties, such as spin-labeled proteins, prior to experiment.

Measurement of reactive species production by nanoparticles prepared in biologically relevant media

Exposure to nanoparticles may pose a risk to health and this hypothesis is currently being investigated by toxicologists. Although the mechanism of nanoparticle toxicity has been shown to be mediated, in part, by oxidative stress, the precise mechanism and molecules involved are still unknown. In light of this, the evaluation of the oxidative potential of nanoparticles is an important consideration in measuring their toxicity. The aim of this study was to examine the use of a fluorogenic probe, 2',7'-dichlorofluorescin (DCFH), in a cell-free assay system and to assess the relationship between the results obtained with this method and with the reactive species formation observed in cells. In order to obtain a well-dispersed nanoparticle suspension, bovine serum albumin (BSA) and dipalmitoyl phosphatidyl choline (DPPC) addition in suspension medium was investigated. Both 1% BSA and 0.025% DPPC added to the medium significantly improved the stability of the nanoparticle suspension, decreasing the extent of particle agglomeration and settling over time. In a cell-free system, reactive oxygen species (ROS) production by 14nm carbon black particles (CB) suspended in DPPC was higher than that measured with the other suspensions (saline or 1% BSA). A greater ROS production was observed in MonoMac 6 cells (MM6) following treatment with 14nm CB suspended in medium containing BSA and/or DPPC compared to medium alone. In conclusion, 1% BSA and 0.025% DPPC solution was the most efficient for the preparation of a nanoparticle suspension and to measure their oxidative potential.

Phylogenetics and Mitochondrial DNA

Phylogenetic analysis can be conducted using a variety of methods, generally classified as distancebased or character-based approaches. Patterns found through phylogenetic analysis of human mitochondrial DNA (mtDNA) sequences have revealed a wealth of information in such disparate fields as the human evolution; the movement of human lineages throughout history (phylogeography); and the susceptibility of certain groups to devastating diseases. Forensic mtDNA analysis has also benefited from the use of these methods. Phylogenetic assessment of forensic mtDNA databases has revealed a consistency with published data at a depth of analysis that is not attainable with basic population genetic methods. The detailed characteristics of specific sites within a mtDNA sequence are best assessed using phylogenetic methods. These studies have identified the most informative sites for individual differentiation, while also providing quality assurance metrics to apply to individual mtDNA profiles or entire databases. Such a level of evaluation and understanding enhances the interpretation of forensic casework.

Parametrization and validation of a force field for liquid-crystal forming molecules

First principles density functional calculations have been carried out to determine the structures and conformational energies of a series of liquid-crystal fragment molecules. The calculations have been used to derive a molecular mechanics force field that describes a subset of commonly occurring liquid-crystal molecules. The force field has been used to carry out molecular dynamics simulations of the bulk phase for these fragment molecules. Computed densities and heats of vaporization are in good agreement with experimental data. These results should be useful in future molecular dynamics simulations of liquid-crystal systems.

Size-dependent proinflammatory effects of ultrafine polystyrene particles: a role for surface area and oxidative stress in the enhanced activity of ultrafines

Studies into the effects of ultrafine particles in the lung have shown adverse effects considered to be due in part to the particle size. Air pollution particles (PM(10)) are associated with exacerbations of respiratory disease and deaths from cardiovascular causes in epidemiological studies and the ultrafine fraction of PM(10) has been hypothesized to play an important role. The aim of the present study was to investigate proinflammatory responses to various sizes of polystyrene particles as a simple model of particles of varying size including ultrafine. In the animal model, we demonstrated that there was a significantly greater neutrophil influx into the rat lung after instillation of 64-nm polystyrene particles compared with 202- and 535-nm particles and this was mirrored in other parameters of lung inflammation, such as increased protein and lactate dehydrogenase in bronchoalveolar lavage. When surface area instilled was plotted against inflammation, these two variables were directly proportional and the line passed through zero. This suggests that surface area drives inflammation in the short term and that ultrafine particles cause a greater inflammatory response because of the greater surface area they possess. In vitro, we measured the changes in intracellular calcium concentration in mono mac 6 cells in view of the potential role of calcium as a signaling molecule. Calcium changes after particle exposure may be important in leading to proinflammatory gene expression such as chemokines. We demonstrated that only ultrafine polystyrene particles induced a significant increase in cytosolic calcium ion concentration. Experiments using dichlorofluorescin diacetate demonstrated greater oxidant activity of the ultrafine particles, which may explain their activity in these assays. There were significant increases in IL-8 gene expression in A549 epithelial cells after treatment with the ultrafine particles but not particles of other sizes. These findings suggest that ultrafine particles composed of low-toxicity material such as polystyrene have proinflammatory activity as a consequence of their large surface area. This supports a role for such particles in the adverse health effects of PM(10).

An IgH Enhancer That Drives Transcription through Basic Helix-Loop-Helix and Oct Transcription Factor Binding Motifs

The transcriptional enhancer (E(mu)3') of the IgH locus of the channel catfish, Ictalurus punctatus, shows strong B cell-specific activity and differs from the mammalian E(mu) enhancer in both location and structure. It occurs between the mu and delta genes and contains numerous transcription factor binding sites, predominantly octamer and muE5 motifs of consensus and variant sequences. It lacks the classical muA-muE3(CBF)-muB core array of binding motifs seen within mammalian IgH E(mu) enhancers. To determine the functionally important motifs, a series of mutant enhancers was created using sequence-targeted polymerase chain reaction. Whereas the mutation of consensus and variant octamer motifs (individually or in multiples) decreased enhancer function, mutation of a single consensus muE5 motif destroyed the function of this enhancer in mammalian plasmacytomas. Mutation of this consensus muE5 site, combined with mutations of certain octamer sites, destroyed function in catfish B cells. Experiments using artificial enhancers containing multimers of motifs or short regions of the native enhancer suggested that the minimal E(mu)3' enhancer (a) contains a consensus muE5 site and two octamer sites, (b) is B cell-specific, and (c) is active across species. The dependence of an Ig enhancer on sites that bind basic helix-loop-helix and Oct transcription factors has not previously been observed and confirms large differences in structure and function between fish and mammalian IgH enhancers.

Length variation in HV2 of the human mitochondrial DNA control region

Hair samples were typed from three individuals who exhibited length heteroplasmy in the homopolymeric cytosine stretches (C-stretch) in hypervariable region 2 (HV2). The study demonstrated that for different hairs within an individual, the HV2 C-stretch region can vary with respect to the number of cytosines and/or proportion of C-stretch length variants. Length heteroplasmy may occur regardless of the prominent length variant present in this region. Differences in the number of cytosines at the C-stretch region, or a variation in the relative amounts of heteroplasmic length variants, cannot be used to support an interpretation of exclusion.

Pinocytic loading of cytochrome c into intact cells specifically induces caspase-dependent permeabilization of mitochondria: evidence for a cytochrome c feedback loop

Previous studies introduced cytochrome c into intact cells via the disruptive techniques of microinjection or electroporation to provide support for the hypothesis that, in whole cells, cytochrome c release from mitochondria triggers caspase activation and other degradative changes. However, the types of measurements that could be undertaken with these techniques was limited. We used the simple and relatively gentle technique of pinocytic loading to demonstrate that, in intact cells, cytosolic cytochrome c specifically induced activation of caspase-3- and -9-like enzymes, and a loss of mitochondrial polarization coincident with an increase in mitochondrial permeability. Our results support the prediction from in vitro studies that activation of caspases-3 and -9 is downstream of cytochrome c release and provide the first direct evidence that, in whole cells, cytochrome c-dependent caspase-activation can exert a feedback effect to elicit mitochondrial permeabilization and collapse of the mitochondrial trans-membrane potential.

Leptin transport at the blood--cerebrospinal fluid barrier using the perfused sheep choroid plexus model

Leptin is secreted by adipose tissue and thought to regulate appetite at the central level. Several studies have explored the central nervous system (CNS) entry of this peptide across the blood-brain and blood-cerebrospinal fluid (CSF) barriers in parallel, but this is the first to explore the transport kinetics of leptin across the choroid plexus (blood-CSF barrier) in isolation from the blood-brain barrier (BBB). This is important as the presence of both barriers can lead to ambiguous results from transport studies. The model used was the isolated Ringer perfused sheep choroid plexus. The steady-state extraction of [(125)I]leptin (7.5 pmol l(-1)) at the blood face of the choroid plexus was 21.1+/-5.7%, which was greater than extraction of the extracellular marker, giving a net cellular uptake for [(125)I]leptin (14.0+/-3.7%). In addition, trichloroacetic acid precipitable [(125)I] was detected in newly formed CSF, indicating intact protein transfer across the blood-CSF barrier. Human plasma concentrations of leptin are reported to be 0.5 nM. Experiments using 0.5 nM leptin in the Ringer produced a concentration of leptin in the CSF of 12 pM (similar to that measured in humans). [(125)I]Leptin uptake at the blood-plexus interface using the single-circulation paired tracer dilution technique (uptake in <60 s) indicated the presence of a saturable transport system, which followed Michaelis-Menten-type kinetics (K(m)=16.3+/-1.8 nM, V(max)=41.2+/-1.4 pmol min(-1) g(-1)), and a non-saturable component (K(d)=0.065+/-0.002 ml min(-1) g(-1)). In addition, secretion of new CSF by the choroid plexuses was significantly decreased with leptin present. This study indicates that leptin transport at the blood-CSF barrier is via saturable and non-saturable mechanisms and that the choroid plexus is involved in the regulation of leptin availability to the brain.

Clusterin is an ATP-independent chaperone with very broad substrate specificity that stabilizes stressed proteins in a folding-competent state

We recently reported that the ubiquitous, secreted protein clusterin has chaperone activity in vitro [Humphreys et al. (1999) J. Biol. Chem. 274, 6875-6881]. In this study, we demonstrate that clusterin (i) inhibits stress-induced precipitation of a very broad range of structurally divergent protein substrates, (ii) binds irreversibly via an ATP-independent mechanism to stressed proteins to form solubilized high molecular weight complexes, (iii) lacks detectable ATPase activity, (iv) when acting alone, does not effect refolding of stressed proteins in vitro, and (v) stabilizes stressed proteins in a state competent for refolding by heat shock protein 70 (HSP70). Furthermore, we show that, at physiological levels, clusterin inhibits stress-induced precipitation of proteins in undiluted human serum. Clusterin represents the first identified secreted mammalian chaperone. However, reports from others suggest that, at least under stress conditions, clusterin may be retained within cells to exert a protective effect. Regardless of the topological site(s) of action, the demonstration that clusterin can stabilize stressed proteins in a refolding-competent state suggests that, during stresses, the action of clusterin may inhibit rapid and irreversible protein precipitation and produce a reservoir of inactive but stabilized molecules from which other refolding chaperones can subsequently salvage functional proteins.

Induction of angiogenesis by hyperplastic colonic mucosa adjacent to colon cancer

We determined whether hyperplastic mucosa adjacent to colon cancer contributes to neoplastic angiogenesis. Surgical specimens of human colon cancer (40 Dukes' stage B and 34 Dukes' stage C) were analyzed by immunohistochemistry for expression of proliferative and angiogenic molecules. The mucosa adjacent to Dukes' stage C tumors (but not Dukes' stage B tumors) had a higher Ki-67 labeling index and a higher expression of epidermal growth factor receptor and transforming growth factor-alpha than distant mucosa. The expression levels of vascular endothelial growth factor, basic fibroblast growth factor, interleukin-8, and the vascular density in the adjacent mucosa were similar to those in the tumor lesions and significantly higher than those in the distant mucosa. The expression of interferon-beta inversely correlated with the level of pro-angiogenic molecules and the vascular density. The injection of metastatic human colon cancer cells and murine colon cancer cells into the cecal wall of mice induced hyperplastic changes in the adjacent mucosa which expressed higher levels of epidermal growth factor receptor, basic fibroblast growth factor, and vascular endothelial growth factor, and lower levels of interferon-beta than did the control mucosa, which directly correlated with the degree of hyperplasia. These data suggest that metastatic human colon cancer cells can induce hyperplasia in the adjacent mucosa, which in turn produces angiogenic molecules that contribute to neoplastic angiogenesis.

In vitro toxicology of respirable Montserrat volcanic ash

OBJECTIVES

In July 1995 the Soufriere Hills volcano on the island of Montserrat began to erupt. Preliminary reports showed that the ash contained a substantial respirable component and a large percentage of the toxic silica polymorph, cristobalite. In this study the cytotoxicity of three respirable Montserrat volcanic ash (MVA) samples was investigated: M1 from a single explosive event, M2 accumulated ash predominantly derived from pyroclastic flows, and M3 from a single pyroclastic flow. These were compared with the relatively inert dust TiO(2) and the known toxic quartz dust, DQ12.

METHODS

Surface area of the particles was measured with the Brunauer, Emmet, and Teller (BET) adsorption method and cristobalite content of MVA was determined by x ray diffraction (XRD). After exposure to particles, the metabolic competence of the epithelial cell line A549 was assessed to determine cytotoxic effects. The ability of the particles to induce sheep blood erythrocyte haemolysis was used to assess surface reactivity.

RESULTS

Treatment with either MVA, quartz, or titanium dioxide decreased A549 epithelial cell metabolic competence as measured by ability to reduce 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). On addition of mannitol, the cytotoxic effect was significantly less with M1, quartz, and TiO(2). All MVA samples induced a dose dependent increase in haemolysis, which, although less than the haemolysis induced by quartz, was significantly greater than that induced by TiO(2). Addition of mannitol and superoxide dismutase (SOD) significantly reduced the haemolytic activity only of M1, but not M2 or M3, the samples derived from predominantly pyroclastic flow events.

CONCLUSIONS

Neither the cristobalite content nor the surface area of the MVA samples correlated with observed in vitro reactivity. A role for reactive oxygen species could only be shown in the cytotoxicity of M1, which was the only sample derived from a purely explosive event. These results suggest that in general the bioreactivity of MVA samples in vitro is low compared with pure quartz, but that the bioreactivity and mechanisms of biological interaction may vary according to the ash source.

Clusterin protein diversity in the primate eye

PURPOSE

The clusterin gene encodes a multi-functional protein that has been identified in different tissues, including a number of different eye tissues, primarily in the mouse and to a much lesser extent in humans. Clusterin has been implicated in a number of cellular processes such as lipid transport, membrane integrity, apoptosis, and neurodegeneration, all of which could be important to the biology of the eye. In the current communication, we provide data that confirms the expression of clusterin in a number of different human eye tissues and establishes the expression profile of this gene in monkey derived eye tissues. The issue that we sought to examine is whether a broad profile of clusterin expression in the eye is consistent in primates (monkey and human).

METHODS

The majority of our study was done using monkey eye tissues. Where possible, we have used human tissues in order to confirm published findings. Northern and western analysis was performed using tissues derived from monkey eyes. In situ hybridization and immunochemistry were carried out on human eye sections.

RESULTS

Clusterin mRNA is expressed in primate lens, cornea, limbus, sclera, orbital muscle, ciliary body, retina, RPE/choroid, and RPE cells in culture. Western analysis revealed that two major groups of clusterin exist in the eye, a high molecular weight group (>100 kDa) and a second group consisting of at least five clusterin species that are all approximately 80 kDa. Analysis of conditioned media from RPE cells cultured on permeable supports suggests that different forms of clusterin display alternative patterns of secretion.

CONCLUSIONS

Clusterin is expressed in a broad range of eye tissues in both human and monkey, suggesting that this is a characteristic feature in primates. We demonstrate for the first time that a diverse number of clusterin isoforms were observed in monkey eye tissues by western analysis. Meanwhile, the molecular size of clusterin mRNA detected in the array of tissues are identical in size, suggesting that the nature of the diversity in clusterin forms is due to post-translational modifications. In addition, new insights were made in defining clusterin expression in ciliary body, cornea, and the retinal pigment epithelium.

Ahmed glaucoma valve implant vs trabeculectomy in the surgical treatment of glaucoma: a randomized clinical trial

PURPOSE

To compare the short- and intermediate-term results of two commonly used glaucoma surgical procedures, trabeculectomy and Ahmed glaucoma valve implant.

METHODS

A randomized clinical trial was performed at two international centers. One eye each of consecutive patients requiring glaucoma surgery for intraocular pressure control was randomized to receive either trabeculectomy or the Ahmed implant.

RESULTS

Of the 117 patients, 62 were randomized to trabeculectomy and 55 to the Ahmed implant. With a mean follow-up of 9.7 months, the trabeculectomy group had statistically lower intraocular pressures at weeks 6 to 15 (12.6 mm Hg vs 16.4 mm Hg) and months 11 to 13 (11.4 mm Hg vs 17.2 mm Hg) than the Ahmed implant group. Compared with preoperative status, no statistically significant differences between groups were noted for visual acuity, visual field, lens status, and final anterior chamber depth. The cumulative probabilities of success (intraocular pressure <21 mm Hg and at least 15% reduction in intraocular pressure from preoperative level) were 83.6% for trabeculectomy and 88.1% for Ahmed implant (P =.43). However, the Ahmed implant group had a greater adjunctive medication requirement. On the last visit, 10 of the trabeculectomy eyes and 19 of the Ahmed implant eyes required at least one topical medication (P =.01). There was no statistically significant difference in the rate of complications between the two groups.

CONCLUSIONS

Lower mean intraocular pressures were noted for the trabeculectomy group. All other results, including success (as defined in this study) and frequency of complications, were comparable between the two groups.

Telomerase expression and telomere length in immortal leukocyte lines from channel catfish

Normal channel catfish leukocytes readily undergo spontaneous in vitro immortalization yielding functionally active diploid cell lines. Since telomerase activation appears to be a critical step in the establishment of immortal mammalian cells, studies were undertaken to determine if and when telomerase expression occurs during the in vitro immortalization process of channel catfish leukocytes. To this end, freshly isolated peripheral blood leukocytes (PBL) from normal fish were shown to exhibit low to undetectable levels of telomerase activity and within four days after culture initiation showed dramatic increases in telomerase activity which typically remained high for at least four weeks. This activity then declined, concomitant with decreases in cellular proliferation and increases in cell death. Cells which escaped this culture "crisis" re-expressed high levels of telomerase activity indefinitely. Although telomerase activity was expressed early in the immortalization process, clonal cell lines derived from these cultures had relatively short telomeres. These results suggest that telomerase expression in catfish leukocytes is activation-induced, and its expression does not necessarily stabilize telomere length until a critically, albeit ill-defined, short length is reached.

MHC class II A genes in the channel catfish (Ictalurus punctatus)

In order to characterize the Major histocompatibility complex (MHC) class II A genes of the channel catfish (Ictalurus punctatus) a cDNA library was screened and PCR was performed. Four different full-length cDNA sequences for MHC class II A genes were obtained from a clonal B cell line derived from an outbred fish. Two different genomic sequences and corresponding cDNAs were obtained from a presumably homozygous gynogenetic catfish. The A genes have five exons and four phase one introns. The first exon encodes the 5' untranslated region (UTR) and leader peptide; the second and third exons encode the alpha1 and alpha2 domains, respectively. The connecting peptide, transmembrane and cytoplasmic domains, as well as part of the 3' UTR, are encoded by the fourth exon and the rest of the 3' UTR is encoded by the fifth exon. Southern blot analyses using an exon three probe revealed two to four hybridizing fragments with considerable restriction fragment length polymorphisms evident among randomly selected outbred channel catfish. These findings are consistent with the presence of at least two functional polymorphic MHC class II A gene loci. An unusual aspect of the channel catfish MHC class II alpha chain is its lack of N-linked glycosylation sites.

Restoration of gap junctional intercellular communication by caffeic acid phenethyl ester (CAPE) in a ras-transformed rat liver epithelial cell line

Caffeic acid phenethyl ester (CAPE), an active ingredient of honeybee propolis, has been identified as having anti-inflammatory, anti-viral and anti-cancer properties. Since the deficiency of gap junctional intercellular communication (GJIC) has been shown to be a characteristic of most cancer cells, this study was designed to test the hypothesis that the anti-carcinogenic activity of CAPE might be related to its ability to restore GJIC in tumorigenic GJIC-deficient cells (WB-ras2 cells). The results showed that CAPE restored GJIC, phosphorylation of connexin 43 (Cx43) and its normal localization on the plasma membrane in WB-ras2 cells after 3 days at 5 microg/ml concentration. Additionally, CAPE inhibited growth in soft agar and decreased the protein level of p21(ras). The results are consistent with the hypothesis that the anti-cancer mechanism of CAPE may be mediated by its ability to restore GJIC.