Antiviral responses in a Jamaican fruit bat intestinal organoid model of SARS-CoV-2 infection

Bats are natural reservoirs for several zoonotic viruses, potentially due to an enhanced capacity to control viral infection. However, the mechanisms of antiviral responses in bats are poorly defined. Here we established a Jamaican fruit bat (JFB, Artibeus jamaicensis) intestinal organoid model of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. Upon infection with SARS-CoV-2, increased viral RNA and subgenomic RNA was detected, but no infectious virus was released, indicating that JFB organoids support only limited viral replication but not viral reproduction. SARS-CoV-2 replication was associated with significantly increased gene expression of type I interferons and inflammatory cytokines. Interestingly, SARS-CoV-2 also caused enhanced formation and growth of JFB organoids. Proteomics revealed an increase in inflammatory signaling, cell turnover, cell repair, and SARS-CoV-2 infection pathways. Collectively, our findings suggest that primary JFB intestinal epithelial cells mount successful antiviral interferon responses and that SARS-CoV-2 infection in JFB cells induces protective regenerative pathways.

Antiviral response mechanisms in a Jamaican Fruit Bat intestinal organoid model of SARS-CoV-2 infection

Bats are natural reservoirs for several zoonotic viruses, potentially due to an enhanced capacity to control viral infection. However, the mechanisms of antiviral responses in bats are poorly defined. Here we established a Jamaican fruit bat (JFB) intestinal organoid model of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. JFB organoids were susceptible to SARS-CoV-2 infection, with increased viral RNA and subgenomic RNA detected in cell lysates and supernatants. Gene expression of type I interferons and inflammatory cytokines was induced in response to SARS-CoV-2 but not in response to TLR agonists. Interestingly, SARS-CoV-2 did not lead to cytopathic effects in JFB organoids but caused enhanced organoid growth. Proteomic analyses revealed an increase in inflammatory signaling, cell turnover, cell repair, and SARS-CoV-2 infection pathways. Collectively, our findings suggest that primary JFB intestinal epithelial cells can mount a successful antiviral interferon response and that SARS-CoV-2 infection in JFB cells induces protective regenerative pathways.

Archetypal Analysis for neuronal clique detection in low-rate calcium fluorescence imaging

Archetypal analysis (AA) is a versatile data analysis method to cluster distinct features within a data set. Here, we demonstrate a framework showing the power of AA to spatio-temporally resolve events in calcium imaging, an imaging modality commonly used in neurobiology and neuroscience to capture neuronal communication patterns. After validation of our AA-based approach on synthetic data sets, we were able to characterize neuronal communication patterns in recorded calcium waves. Clinical relevance- Transient calcium events play an essential role in brain cell communication, growth, and network formation, as well as in neurodegeneration. To reliably interpret calcium events from personalized medicine data, where patterns may differ from patient to patient, appropriate image processing and signal analysis methods need to be developed for optimal network characterization.

Multi-curvature micropatterns unveil distinct calcium and mitochondrial dynamics in neuronal networks

Tangential curvatures are a key geometric feature of tissue folds in the human cerebral cortex. In the brain, these smoother and firmer bends are called gyri and sulci and form distinctive curved tissue patterns imposing a mechanical stimulus on neuronal networks. This stimulus is hypothesized to be essential for proper brain cell function but lacks in most standard neuronal cell assays. A variety of soft lithographic micropatterning techniques can be used to integrate round geometries in cell assays. Most microfabricated patterns, however, focus only on a small set of defined curvatures. In contrast, curvatures in the brain span a wide physical range, leaving it unknown which precise role distinct curvatures may play on neuronal cell signaling. Here we report a hydrogel-based multi-curvature design consisting of over twenty bands of distinct parallel curvature ranges to precisely engineer neuronal networks' growth and signaling under patterns of arcs. Monitoring calcium and mitochondrial dynamics in primary rodent neurons grown over two weeks in the multi-curvature patterns, we found that static calcium signaling was locally attenuated under higher curvatures (k > 0.01 μm-1). In contrast, to randomize growth, transient calcium signaling showed higher synchronicity when neurons formed networks in confined multi-curvature patterns. Additionally, we found that mitochondria showed lower motility under high curvatures (k > 0.01 μm-1) than under lower curvatures (k < 0.01 μm-1). Our results demonstrate how sensitive neuronal cell function may be linked and controlled through specific curved geometric features. Furthermore, the hydrogel-based multi-curvature design possesses high compatibility with various surfaces, allowing a flexible integration of geometric features into next-generation neuro devices, cell assays, tissue engineering, and implants.

Low-cost calcium fluorometry for long-term nanoparticle studies in living cells

Calcium fluorometry is critical to determine cell homeostasis or to reveal communication patterns in neuronal networks. Recently, characterizing calcium signalling in neurons related to interactions with nanomaterials has become of interest due to its therapeutic potential. However, imaging of neuronal cell activity under stable physiological conditions can be either very expensive or limited in its long-term capability. Here, we present a low-cost, portable imaging system for long-term, fast-scale calcium fluorometry in neurons. Using the imaging system, we revealed temperature-dependent changes in long-term calcium signalling in kidney cells and primary cortical neurons. Furthermore, we introduce fast-scale monitoring of synchronous calcium activity in neuronal cultures in response to nanomaterials. Through graph network analysis, we found that calcium dynamics in neurons are temperature-dependent when exposed to chitosan-coated nanoparticles. These results give new insights into nanomaterial-interaction in living cultures and tissues based on calcium fluorometry and graph network analysis.

Force-Mediating Magnetic Nanoparticles to Engineer Neuronal Cell Function

Cellular processes like membrane deformation, cell migration, and transport of organelles are sensitive to mechanical forces. Technically, these cellular processes can be manipulated through operating forces at a spatial precision in the range of nanometers up to a few micrometers through chaperoning force-mediating nanoparticles in electrical, magnetic, or optical field gradients. But which force-mediating tool is more suitable to manipulate cell migration, and which, to manipulate cell signaling? We review here the differences in forces sensation to control and engineer cellular processes inside and outside the cell, with a special focus on neuronal cells. In addition, we discuss technical details and limitations of different force-mediating approaches and highlight recent advancements of nanomagnetics in cell organization, communication, signaling, and intracellular trafficking. Finally, we give suggestions about how force-mediating nanoparticles can be used to our advantage in next-generation neurotherapeutic devices.

The phosphodiesterase 4 inhibitor apremilast inhibits Th1 but promotes Th17 responses induced by 6-sulfo LacNAc (slan) dendritic cells

BACKGROUND

The phosphodiesterase 4 (PDE4) inhibitor apremilast increases cellular cAMP levels and has proven effective in the treatment of psoriasis and psoriasis arthritis. We recently described 6-sulfo LacNAc dendritic cells (slanDCs) as immature DCs in blood and as a subset of inflammatory dermal DCs in psoriasis with a pronounced capacity to produce proinflammatory cytokines and to program Th17/Th1 T cell responses.

OBJECTIVE

The aim of this study was to investigate possible immune regulatory effects of the PDE4 inhibitor apremilast on slanDCs.

METHODS

In vitro studies were performed analyzing the effects of apremilast on the proinflammatory function of slanDCs and their capacity to induce Th1/Th17-biased T cell responses.

RESULTS

Increasing cAMP levels in slanDCs by PDE4 inhibition strongly reduced production of IL-12 and TNF-α. In line with these findings, co-culture experiments with apremilast-pulsed slanDCs and allogeneic T cells either from psoriasis patients or healthy controls, revealed a significant reduction of IFN-γ production and expression of the transcription factor T-bet. In parallel, production of IL-23 and IL-1ß by slanDCs was increased and co-cultured T cells revealed a largely augmented IL-17 production and an upregulated RORyt expression.

CONCLUSIONS

We here demonstrate anti-inflammatory as well as Th17-promoting effects of apremilast when studying blood precursors of human inflammatory dermal dendritic cells. In the concert of the broad anti-inflammatory effects of apremilast on keratinocytes, fibroblasts and endothelial cells, the dual effect on slan⁺ inflammatory dermal DCs should be taken into account and may constrain therapeutic responses.

Modulating motility of intracellular vesicles in cortical neurons with nanomagnetic forces on-chip

Vesicle transport is a major underlying mechanism of cell communication. Inhibiting vesicle transport in brain cells results in blockage of neuronal signals, even in intact neuronal networks. Modulating intracellular vesicle transport can have a huge impact on the development of new neurotherapeutic concepts, but only if we can specifically interfere with intracellular transport patterns. Here, we propose to modulate motion of intracellular lipid vesicles in rat cortical neurons based on exogenously bioconjugated and cell internalized superparamagnetic iron oxide nanoparticles (SPIONs) within microengineered magnetic gradients on-chip. Upon application of 6-126 pN on intracellular vesicles in neuronal cells, we explored how the magnetic force stimulus impacts the motion pattern of vesicles at various intracellular locations without modulating the entire cell morphology. Altering vesicle dynamics was quantified using, mean square displacement, a caging diameter and the total traveled distance. We observed a de-acceleration of intercellular vesicle motility, while applying nanomagnetic forces to cultured neurons with SPIONs, which can be explained by a decrease in motility due to opposing magnetic force direction. Ultimately, using nanomagnetic forces inside neurons may permit us to stop the mis-sorting of intracellular organelles, proteins and cell signals, which have been associated with cellular dysfunction. Furthermore, nanomagnetic force applications will allow us to wirelessly guide axons and dendrites by exogenously using permanent magnetic field gradients.

Monitoring of single and double lipid membrane formation with high spatiotemporal resolution using evanescent light scattering microscopy

Formation and quality of single solid supported lipid membranes and double lipid membranes were investigated with single vesicle resolution using label-free evanescence light scattering microscopy (EvSM). For the formation of double lipid membranes we made use of electrostatic interaction between charged lipids and oppositely charged cations.

The Age of Cortical Neural Networks Affects Their Interactions with Magnetic Nanoparticles

Despite increasing use of nanotechnology in neuroscience, the characterization of interactions between magnetic nanoparticles (MNPs) and primary cortical neural networks remains underdeveloped. In particular, how the age of primary neural networks affects MNP uptake and endocytosis is critical when considering MNP-based therapies for age-related diseases. Here, primary cortical neural networks are cultured up to 4 weeks and with CCL11/eotaxin, an age-inducing chemokine, to create aged neural networks. As the neural networks are aged, their association with membrane-bound starch-coated ferromagnetic nanoparticles (fMNPs) increases while their endocytic mechanisms are impaired, resulting in reduced internalization of chitosan-coated fMNPs. The age of the neurons also negates the neuroprotective effects of chitosan coatings on fMNPs, attributing to decreased intracellular trafficking and increased colocalization of MNPs with lysosomes. These findings demonstrate the importance of age and developmental stage of primary neural cells when developing in vitro models for fMNP therapeutics targeting age-related diseases.

Induction of Calcium Influx in Cortical Neural Networks by Nanomagnetic Forces

Nanomagnetic force stimulation with ferromagnetic nanoparticles was found to trigger calcium influx in cortical neural networks without observable cytotoxicity. Stimulated neural networks showed an average of 20% increment in calcium fluorescence signals and a heightened frequency in calcium spiking. These effects were also confined spatially to areas with engineered high magnetic field gradients. Furthermore, blockage of N-type calcium channels inhibited the stimulatory effects of the nanomagnetic forces, suggesting the role of mechano-sensitive ion channels in mediating calcium influx.

[Retinal bleeding and venous stasis in a 10-month-old infant after a fall?]

This report describes the case of a 10-month-old infant, who was delivered to our hospital by the emergency physician intubated and in an unclear unconscious state. The father reported that the child had fallen from the couch to the ground. The consulted ophthalmologist reported venous stasis in both eyes including intraretinal and preretinal bleeding in all four quadrants, a diffuse vitreous hemorrhage in the right eye and temporal retinal wrinkling in both eyes. Based on these particular clinical findings a shaken baby syndrome was suspected. This report demonstrates the importance of recognizing and correctly interpreting the typical ophthalmological signs of physical child abuse in order to detect and prevent further mistreatment of children; moreover, the increasing importance of photographic documentation and histological work-up of the findings for forensic reasons are emphasized.

On-Chip Isothermal Nucleic Acid Amplification on Flow-Based Chemiluminescence Microarray Analysis Platform for the Detection of Viruses and Bacteria

This work presents an on-chip isothermal nucleic acid amplification test (iNAAT) for the multiplex amplification and detection of viral and bacterial DNA by a flow-based chemiluminescence microarray. In a principle study, on-chip recombinase polymerase amplification (RPA) on defined spots of a DNA microarray was used to spatially separate the amplification reaction of DNA from two viruses (Human adenovirus 41, Phi X 174) and the bacterium Enterococcus faecalis, which are relevant for water hygiene. By establishing the developed assay on the microarray analysis platform MCR 3, the automation of isothermal multiplex-amplification (39 °C, 40 min) and subsequent detection by chemiluminescence imaging was realized. Within 48 min, the microbes could be identified by the spot position on the microarray while the generated chemiluminescence signal correlated with the amount of applied microbe DNA. The limit of detection (LOD) determined for HAdV 41, Phi X 174, and E. faecalis was 35 GU/μL, 1 GU/μL, and 5 × 10(3) GU/μL (genomic units), which is comparable to the sensitivity reported for qPCR analysis, respectively. Moreover the simultaneous amplification and detection of DNA from all three microbes was possible. The presented assay shows that complex enzymatic reactions like an isothermal amplification can be performed in an easy-to-use experimental setup. Furthermore, iNAATs can be potent candidates for multipathogen detection in clinical, food, or environmental samples in routine or field monitoring approaches.

Flexible and stretchable micromagnet arrays for tunable biointerfacing

A process to surface pattern polydimethylsiloxane (PDMS) with ferromagnetic structures of varying sizes (micrometer to millimeter) and thicknesses (>70 μm) is developed. Their flexibility and magnetic reach are utilized to confer dynamic, additive properties to a variety of substrates, such as coverslips and Eppendorf tubes. It is found that these substrates can generate additional modes of magnetic droplet manipulation, and can tunably steer magnetic-cell organization.

Research highlights: cell separation at the bench and beyond

We highlight recent progress in applying micro- and nanotechnology enabled cell separations to life sciences and clinical use. Microfluidic systems operate on a scale that matches that of cells (10-100 μm) and therefore allow interfacing and separations that are sensitive at this scale. Given the corresponding dimensions, it is not surprising that a wide array of microfluidic cell separation technologies have been developed using hydrodynamic, electrical, magnetic and optical forces, and have been applied to a range of biological and clinical problems in sample preparation. Passive separation approaches have distinct advantages for point of care applications or when downstream cell-based therapies are envisioned. We highlight a recent approach that allows for passive hydrodynamic filtering of cells over almost two orders of magnitude in flow conditions, which allowed the researchers to interface with a standard manual pipettor, creating a "microfluidic pipette tip". In a second work, passive separation by size yields distinct populations of mesenchymal stem cells that can be used therapeutically. The researchers report on other biophysical separations that would be expected to refine these cell populations further for the most efficacious cell-based therapies. In an intriguing twist, we highlight a creative idea in which stem cell populations could potentially also be extracted from a patient with less invasive surgeries, performing the separation using magnetic nanoparticles in vivo without bulk tissue disruption. New cell separation technologies will continue to be demonstrated, however, a major research thrust appears to be now developing these technologies to address unique application niches in point-of-care sample preparation for research and diagnostics or cell-based therapies.

Engineering cortical neuron polarity with nanomagnets on a chip

Intra- and extracellular signaling play critical roles in cell polarity, ultimately leading to the development of functional cell-cell connections, tissues, and organs. In the brain, pathologically oriented neurons are often the cause for disordered circuits, severely impacting motor function, perception, and memory. Aside from control through gene expression and signaling pathways, it is known that nervous system development can be manipulated by mechanical stimuli (e.g., outgrowth of axons through externally applied forces). The inverse is true as well: intracellular molecular signals can be converted into forces to yield axonal outgrowth. The complete role played by mechanical signals in mediating single-cell polarity, however, remains currently unclear. Here we employ highly parallelized nanomagnets on a chip to exert local mechanical stimuli on cortical neurons, independently of the amount of superparamagnetic nanoparticles taken up by the cells. The chip-based approach was utilized to quantify the effect of nanoparticle-mediated forces on the intracellular cytoskeleton as visualized by the distribution of the microtubule-associated protein tau. While single cortical neurons prefer to assemble tau proteins following poly-L-lysine surface cues, an optimal force range of 4.5-70 pN by the nanomagnets initiated a tau distribution opposed to the pattern cue. In larger cell clusters (groups comprising six or more cells), nanoparticle-mediated forces induced tau repositioning in an observed range of 190-270 pN, and initiation of magnetic field-directed cell displacement was observed at forces above 300 pN. Our findings lay the groundwork for high-resolution mechanical encoding of neural networks in vitro, mechanically driven cell polarization in brain tissues, and neurotherapeutic approaches using functionalized superparamagnetic nanoparticles to potentially restore disordered neural circuits.

[Pulmonary neuroendocrine neoplasms]

The pulmonary neuroendocrine neoplasms originate from the enterochromaffin cells which are diffusely distributed in the body. The incidence of these tumors has increased significantly in recent decades due to the available diagnostics. They make up about 1-2% of all lung tumors and 20-30% of all neuroendocrine neoplasms. The current WHO classification from 2004 divides them into typical carcinoids (TC), atypical carcinoids (AC), large cell neuroendocrine carcinomas (LCNEC) and small cell carcinomas (SCLC). The major neuroendocrine biomarkers are chromogranin A, synaptophysin and CD56. TC have a low mitotic rate of <2 mitoses/2mm(2) (10 HPF), whereas the mitotic rate of the AC is 2-10 mitoses/2 mm(2) (10 HPF). The Ki-67 staining is helpful to distinguish typical and atypical carcinoids from the highly malignant LCNEC and SCLC. Clinically, the patient presents usually with cough, hemoptysis or bronchial obstruction. The occurrence of a carcinoid or Cushing's syndrome and a tumor-associated acromegaly are rare. Surgical resection with radical lymph node dissection is the treatment of choice for achieving long-term survival. Endoscopic resection of the endobronchial tumor growth is a good alternative for inoperable endobronchially localized tumors. Peptide receptor radionuclide therapy (PRRT) is a promising treatment option for patients with metastatic or unresectable pulmonary neuroendocrine tumors. New targeted therapies using angiogenesis inhibitors, mTOR inhibitors, and tyrosine kinase inhibitors are being tested for their effectiveness in many previous studies. Typical carcinoid tumors metastasize less frequently than AC, the 5-year survival rate of patients with TC being over 90%. Patients with AC have a 5-year survival rate between 35% and 87%. The highly malignant LCNEC and SCLC, on the other hand, have a 5-year survival rate between 15% and 57%, and <5% respectively. The increasing number of therapeutic options and diagnostic procedures requires a multidisciplinary approach and decision-making in multidisciplinary tumor conferences to ensure a personalized treatment approach. Therefore patients with a neuroendocrine neoplasm of the lung should be treated in specialized centers.

Research highlights: Microtechnologies for engineering the cellular environment

In this issue we highlight recent microtechnology-enabled approaches to control the physical and biomolecular environment around cells: (1) developing micropatterned surfaces to quantify cell affinity choices between two adhesive patterns, (2) controlling topographical cues to align cells and improve reprogramming to a pluripotent state, and (3) controlling gradients of biomolecules to maintain pluripotency in embryonic stem cells. Quantitative readouts of cell-surface affinity in environments with several cues should open up avenues in tissue engineering where self-assembly of complex multi-cellular structures is possible by precisely engineering relative adhesive cues in three dimensional constructs. Methods of simple and local epigenetic modification of chromatin structure with microtopography and biomolecular gradients should also be of use in regenerative medicine, as well as in high-throughput quantitative analysis of external signals that impact and can be used to control cells. Overall, approaches to engineer the cellular environment will continue to be an area of further growth in the microfluidic and lab on a chip community, as the scale of the technologies seamlessly matches that of biological systems. However, because of regulations and other complexities with tissue engineered therapies, these micro-engineering approaches will likely first impact organ-on-a-chip technologies that are poised to improve drug discovery pipelines.

Acoustic monitoring of changes in well-defined hyaluronan layers exposed to chondrocytes

The interaction of human-derived chondrocytes and thin hyaluronan layers was studied using the quartz crystal microbalance with dissipation (QCM-D) technique combined with light microscopy.

Advances in high-throughput single-cell microtechnologies

Micro-scale biological tools that have allowed probing of individual cells--from the genetic, to proteomic, to phenotypic level--have revealed important contributions of single cells to direct normal and diseased body processes. In analyzing single cells, sample heterogeneity between and within specific cell types drives the need for high-throughput and quantitative measurement of cellular parameters. In recent years, high-throughput single-cell analysis platforms have revealed rare genetic subpopulations in growing tumors, begun to uncover the mechanisms of antibiotic resistance in bacteria, and described the cell-to-cell variations in stem cell differentiation and immune cell response to activation by pathogens. This review surveys these recent technologies, presenting their strengths and contributions to the field, and identifies needs still unmet toward the development of high-throughput single-cell analysis tools to benefit life science research and clinical diagnostics.

TLR7/8 agonists trigger immunostimulatory properties of human 6-sulfo LacNAc dendritic cells

Imiquimod and resiquimod represent Toll-like receptor (TLR) 7 and 8 agonists, which emerged as attractive candidates for tumor therapy. To elucidate immune cells, which mainly contribute to TLR7/8-mediated antitumoral activity, we investigated the impact of imiquimod and resiquimod on native human 6-sulfo LacNAc (slan) dendritic cells (DCs). We found that both TLR7/8 agonists significantly improve the release of various proinflammatory cytokines by slanDCs and promote their tumor-directed cytotoxic activity. Furthermore, resiquimod efficiently augmented the ability of slanDCs to stimulate T cells and natural killer cells. These results indicate that imiquimod and resiquimod trigger various immunostimulatory properties of slanDCs, which may contribute to their antitumor effects.

Astrocyte-neuron co-culture on microchips based on the model of SOD mutation to mimic ALS

Amyotrophic lateral sclerosis (ALS) is the most common motor neuron disease. ALS is believed to be a non-cell autonomous condition, as other cell types, including astrocytes, have been implicated in disease pathogenesis. Hence, to facilitate the development of therapeutics against ALS, it is crucial to better understand the interactions between astrocytes and neural cells. Furthermore, cell culture assays are needed that mimic the complexity of cell to cell communication at the same time as they provide control over the different microenvironmental parameters. Here, we aim to validate a previously developed microfluidic system for an astrocyte-neuron cell culture platform, in which astrocytes have been genetically modified to overexpress either a human wild-type (WT) or a mutated form of the super oxide dismutase enzyme 1 (SOD1). Cortical neural cells were co-cultured with infected astrocytes and studied for up to two weeks. Using our microfluidic device that prevents direct cell to cell contact, we could evaluate neural cell response in the vicinity of astrocytes. We showed that neuronal cell density was reduced by about 45% when neurons were co-cultured with SOD-mutant astrocytes. Moreover, we demonstrated that SOD-WT overexpressing astrocytes reduced oxidative stress on cortical neurons that were in close metabolic contact. In contrast, cortical neurons in metabolic contact with SOD-mutant astrocytes lost their synapsin protein expression after severe glutamate treatment, an indication of the toxicity potentiating effect of the SOD-mutant enzyme.

Synergistic NGF/B27 gradients position synapses heterogeneously in 3D micropatterned neural cultures

Native functional brain circuits show different numbers of synapses (synaptic densities) in the cerebral cortex. Until now, different synaptic densities could not be studied in vitro using current cell culture methods for primary neurons. Herein, we present a novel microfluidic based cell culture method that combines 3D micropatterning of hydrogel layers with linear chemical gradient formation. Micropatterned hydrogels were used to encapsulate dissociated cortical neurons in laminar cell layers and neurotrophic factors NGF and B27 were added to influence the formation of synapses. Neurotrophic gradients allowed for the positioning of distinguishable synaptic densities throughout a 3D micropatterned neural culture. NGF and B27 gradients were maintained in the microfluidic device for over two weeks without perfusion pumps by utilizing a refilling procedure. Spatial distribution of synapses was examined with a pre-synaptic marker to determine synaptic densities. From our experiments, we observed that (1) cortical neurons responded only to synergistic NGF/B27 gradients, (2) synaptic density increased proportionally to synergistic NGF/B27 gradients; (3) homogeneous distribution of B27 disturbed cortical neurons in sensing NGF gradients and (4) the cell layer position significantly impacted spatial distribution of synapses.

[Hereditary Alzheimer's disease with amyloid angiopathy caused by amyloid precursor protein locus]

We report a patient with early-onset autosomal dominant dementia. The CSF showed increased levels of tau protein and decreased amyloid beta (ratio 42:40) typical for Alzheimer's disease. Cerebral MRI revealed vascular lesions and white-matter changes around the posterior horns of the ventricles with only moderate atrophy of the brain. Susceptibility-weighted imaging detected multiple small hemorrhagic changes. Gene analysis revealed amyloid precursor protein (APP) locus duplication as the cause of hereditary Alzheimer's dementia. The co-occurrence of CSF changes typical for Alzheimer's disease and MRI findings of cerebral amyloid angiopathy is remarkable, as it is also described for APP locus duplication. In conjunction with a family history suggestive of hereditary dementia, such a constellation should lead to enhanced gene analysis.

Clinical and angiographic risk factors for stroke and death within 30 days after carotid endarterectomy and stent-protected angioplasty: a subanalysis of the SPACE study

BACKGROUND

Carotid endarterectomy (CEA) and carotid artery stenting (CAS) are used to prevent ischaemic stroke in patients with stenosis of the internal carotid artery. Better knowledge of risk factors could improve assignment of patients to these procedures and reduce overall risk. We aimed to assess the risk of stroke or death associated with CEA and CAS in patients with different risk factors.

METHODS

We analysed data from 1196 patients randomised to CAS or CEA in the Stent-Protected Angioplasty versus Carotid Endarterectomy in Symptomatic Patients (SPACE) trial. The primary outcome event was death or ipsilateral stroke (ischaemic or haemorrhagic) with symptoms that lasted more than 24 h between randomisation and 30 days after therapy. Six predefined variables were assessed as potential risk factors for this outcome: age, sex, type of qualifying event, side of intervention, degree of stenosis, and presence of high-grade contralateral stenosis or occlusion. The SPACE trial is registered at Current Controlled Trials, with the international standard randomised controlled trial number ISRCTN57874028.

FINDINGS

Risk of ipsilateral stroke or death increased significantly with age in the CAS group (p=0.001) but not in the CEA group (p=0.534). Classification and regression tree analysis showed that the age that gave the greatest separation between high-risk and low-risk populations who had CAS was 68 years: the rate of primary outcome events was 2.7% (8/293) in patients who were 68 years old or younger and 10.8% (34/314) in older patients. Other variables did not differ between the CEA and CAS groups.

INTERPRETATION

Of the predefined covariates, only age was significantly associated with the risk of stroke and death. The lower risk after CAS versus CEA in patients up to 68 years of age was not detectable in older patients. This finding should be interpreted with caution because of the drawbacks of post-hoc analyses.

A virtual valve for smooth contamination-free flow switching

We present a channel geometry that allows for clean switching between different inlets of a microchip without any contamination of the inlets or the downstream flow. We drive this virtual valve with a pneumatic pressure setup that minimizes disturbance of the downstream flow during the switching procedure by simultaneous variation of the pressures applied to the different inlets. We assess the efficiency of the setup by spectroscopic measurement of downstream dye concentrations, and demonstrate its practical utility by sequentially constructing multiple layers of alginate hydrogel. The method is potentially useful for a whole series of further applications, such as changing perfusion liquids for cell culture and cell analysis, metering, chemical-reaction initiation and multi-sample chromatography, to name a few.

The Uromodulin C744G mutation causes MCKD2 and FJHN in children and adults and may be due to a possible founder effect

Autosomal dominant medullary cystic kidney disease type 2 (MCKD2) is a tubulo-in terstitial nephropathy that causes renal salt wasting, hyperuricemia, gout, and end-stage renal failure in the fifth decade of life. This disorder was described to have an age of onset between the age of 20-30 years or even later. Mutations in the Uromodulin (UMOD) gene were published in patients with familial juvenile hyperuricemic nephropathy (FJHN) and MCKD2. Clinical data and blood samples of 16 affected individuals from 11 different kindreds were collected. Mutational analysis of the UMOD gene was performed by exon polymerase chain reaction (PCR) and direct sequencing. We found the heterozygous C744G (Cys248Trp) mutation, which was originally published by our group, in an additional four kindreds from Europe and Turkey. Age of onset ranged from 3 years to 39 years. The phenotype showed a variety of symptoms such as urinary concentration defect, vesicoureteral reflux, urinary tract infections, hyperuricemia, hypertension, proteinuria, and renal hypoplasia. Haplotype analysis showed cosegragation with the phenotype in all eight affected individuals indicating that the C744G mutation may be due to a founder effect. Moreover, we describe a novel T229G (Cys77Gly) mutation in two affecteds of one kindred. Three of the affected individuals were younger than 10 years at the onset of MCKD2/FJHN. Symptoms include recurrent urinary tract infections compatible with the published phenotype of the Umod knockout mouse model. This emphasizes that MCKD2 is not just a disease of the young adult but is also relevant for children.

30 day results from the SPACE trial of stent-protected angioplasty versus carotid endarterectomy in symptomatic patients: a randomised non-inferiority trial

BACKGROUND

Carotid endarterectomy is effective in stroke prevention for patients with severe symptomatic carotid-artery stenosis, and carotid-artery stenting has been widely used as alternative treatment. Since equivalence or superiority has not been convincingly shown for either treatment, we aimed to compare the two.

METHODS

1200 patients with symptomatic carotid-artery stenosis were randomly assigned within 180 days of transient ischaemic attack or moderate stroke (modified Rankin scale score of < or =3) carotid-artery stenting (n=605) or carotid endarterectomy (n=595). The primary endpoint of this hospital-based study was ipsilateral ischaemic stroke or death from time of randomisation to 30 days after the procedure. The non-inferiority margin was defined as less than 2.5% on the basis of an expected event rate of 5%. Analyses were on an intention-to-treat basis. This trial is registered at Current Controlled Trials with the international standard randomised controlled trial number ISRCTN57874028.

FINDINGS

1183 patients were included in the analysis. The rate of death or ipsilateral ischaemic stroke from randomisation to 30 days after the procedure was 6.84% with carotid-artery stenting and 6.34% with carotid endarterectomy (absolute difference 0.51%, 90% CI -1.89% to 2.91%). The one-sided p value for non-inferiority is 0.09.

INTERPRETATION

SPACE failed to prove non-inferiority of carotid-artery stenting compared with carotid endarterectomy for the periprocedural complication rate. The results of this trial do not justify the widespread use in the short-term of carotid-artery stenting for treatment of carotid-artery stenoses. Results at 6-24 months are awaited.

Multiple reversible MR signal changes caused by Epstein-Barr virus encephalitis

This report presents the imaging findings of an unusual case of Epstein-Barr virus (EBV) encephalitis. A young man presented with a short-lasting history of febrile infection, neuropsychologic deficits, ataxia, and seizures. MR imaging revealed fully reversible signal intensities (T2, diffusion-weighted imaging with a decreased apparent diffusion coefficient) in the splenium of the corpus callosum and both posterior hemispheres. EBV infection must be added to the list of differential diagnoses of (reversible) splenial lesions.