Disintegration of the NuRD Complex in Primary Human Muscle Stem Cells in Critical Illness Myopathy.

Critical illness myopathy (CIM) is an acquired, devastating, multifactorial muscle-wasting disease with incomplete recovery. The impact on hospital costs and permanent loss of quality of life is enormous. Incomplete recovery might imply that the function of muscle stem cells (MuSC) is impaired. We tested whether epigenetic alterations could be in part responsible. We characterized human muscle stem cells (MuSC) isolated from early CIM and analyzed epigenetic alterations (CIM n = 15, controls n = 21) by RNA-Seq, immunofluorescence, analysis of DNA repair, and ATAC-Seq. CIM-MuSC were transplanted into immunodeficient NOG mice to assess their regenerative potential. CIM-MuSC exhibited significant growth deficits, reduced ability to differentiate into myotubes, and impaired DNA repair. The chromatin structure was damaged, as characterized by alterations in mRNA of histone 1, depletion or dislocation of core proteins of nucleosome remodeling and deacetylase complex, and loosening of multiple nucleosome-spanning sites. Functionally, CIM-MuSC had a defect in building new muscle fibers. Further, MuSC obtained from the electrically stimulated muscle of CIM patients was very similar to control MuSC, indicating the impact of muscle contraction in the onset of CIM. CIM not only affects working skeletal muscle but has a lasting and severe epigenetic impact on MuSC.

Cerebral Abnormalities in Spina Bifida: A Neuropathological Study.

INTRODUCTION: Spina bifida (SB) is the most common neural tube defect in humans. Here, we analyzed systematically the neuropathological findings of the brain in SB cases. METHODS: 79 cases with SB aperta (SBA) and 6 cases with SB occulta (SBO) autopsied at the Charité Neuropathology from 1974 to 2000 were re-evaluated retrospectively. For this, case files and spinal cord as well as brain sections were studied. RESULTS: While no brain malformations were detected in SBO cases, 95% of SBA cases had brain malformations. Main brain anomalies identified were hydrocephalus (71%), Chiari II malformation (36%), heterotopia (34%), other cerebellar anomalies (36%), gyrification defects (33%), and ependymal denudation (29%). Hydrocephalus was observed as early as gestational week 17 and was highly associated to Chiari II and ependymal denudation. In 55% SBA was accompanied by further anomalies not primarily affecting the CNS. CONCLUSION: We confirm using neuropathologic methods brain malformations in most SBA but none in SBO cases. In addition to our previous radiologic study, we now demonstrate the high prevalence of cerebellar malformations and cerebral heterotopias in SBA. The early detection of hydrocephalus and Chiari II malformation in fetuses raises the question whether these arise parallel rather than in strict temporal sequence.

Improvement of bladder function after bladder augmentation surgery: a report of 26 years of clinical experience.

INTRODUCTION: To assess the long-term effect of bladder augmentation surgery in patients with spina bifida and to identify risk factors for severe bladder dysfunction requiring bladder augmentation. METHODS: A retrospective analysis was performed on 178 patients with spina bifida, 23 of them underwent bladder augmentation. Surgery outcome was evaluated according to urodynamic assessments at three follow-up time points per patient up to 120 months postoperatively. The results were compared to the preoperative situation and to the non-operated control group. Bladder function was evaluated using the modified Hostility score. To identify risk factors for bladder dysfunction requiring bladder augmentation, characteristics such as type of spina bifida, lesion level and therapy of bladder dysfunction were analyzed. RESULTS: A high spinal lesion level is a risk factor for requiring bladder augmentation. In the BA group, significantly more thoracic lesions were found than NBA group, BA: 26.1%, NBA: 8.4% (p = 0.021). With bladder augmentation surgery, the modified Hostility score decreased from a preoperative median value of 4.3 ± 1.4 to 1.6 ± 1.0 at the third postoperative follow-up (FU3 = 61-120 months after surgery). In the reference group, the score of the last urological assessment was 2.0 ± 1.5. The age at which clean intermittent catheterization or anticholinergic medication started had no significant influence on the decision to perform bladder augmentation. DISCUSSION/CONCLUSION: Spina bifida patients with bladder augmentation had a significant improvement of the bladder function even at long-term follow-up. A high level of spinal lesion was a predisposing factor for requiring a bladder augmentation.

Importance of urodynamic evaluation of bladder function after secondary untethering in spina bifida patients: single center experience of 30 years.

INTRODUCTION: A TCS after primary closure of meningomyeloceles is a known complication of the spina bifida disease. Data on the outcome after SSCU surgery is heterogeneous and lacking standardization. Thus we aimed to find a reliable system for assessment of the bladder function before and after SSCU surgery and document postoperative outcome. METHODS: A retrospective study was performed on a cohort of patients with spina bifida diagnosis. In total, 130 patients underwent 182 SSCU surgeries, 56 of those met our inclusion criteria. A classification system, including two different methods, was used. The AC system used baseline pressure and detrusor over activity to define three levels of bladder dysfunction, the second method ranked the severity of bladder dysfunction by awarding points from 0 to 2 for bladder capacity, maximal detrusor pressure during autonomous contractions, leak point pressure and vesicoureteral reflux A high score is correlated with a severe bladder dysfunction. RESULTS: Gender distribution was equally (male: n = 29; 51.8%; female: n = 27; 48.2%). The median age at SSCU was 902 years (range 0.5-22.8 years). After SSCU, the stage improved in 11 patients (19.6%), worsened in 11 (19.6%) patients and remained the same in 34 patients (60.7%) after intervention (AC score). Non-worsening was observed in a total of 45 cases (80.4%) (p < 0.001). MHS score (n = 27, 48.2%) improved, remained unchanged (n = 12, 21.4%), 17 patients worsened (30.4%). Non-worsening in postoperative bladder functional outcome was demonstrated in 39 cases (69.6%) over all (p < 0.005). Regardless of whether bladder function is categorized by AC or MHS, postoperative outcome worsened significantly when SSCU was performed due to increasing deterioration in motor function alone (p < 0.05). Of the 24 cases with NOD as indication, 22 (91.7%) had an unchanged (n = 10; 41.7%) or improved (n = 12; 50.0%), meaning positive neuro-orthopedic outcome, only 2 (8.3%) deteriorated (p < 0.001). CONCLUSION: Our study presents reliable evaluation systems for bladder function in spina bifida patients. Since indications for SSCU surgery differ, it is important to know the possible effects on bladder function after this surgical procedure. Even a mild impairment of bladder function has a risk to deteriorate after SSCU surgery. Particularly interesting becomes this with regard to the fact that the prevalence of TCS might become more frequent with the rising numbers of prenatal closures of meningomyeloceles.

Brain malformations and cognitive performance in spina bifida.

AIM: To systematically characterize radiological features of patients with spina bifida, their relationship to cognitive function, and differences between spina bifida aperta (SBA) and spina bifida occulta (SBO). METHOD: In a retrospective study of 265 patients (117 females, 148 males; median age at imaging 11y, range 1-47y; SBA n=206, SBO n=59), the radiological phenotype was assessed through magnetic resonance imaging (MRI) (SBA n=171, SBO n=59). In 126 patients (SBA n=116, SBO n=10) Kaufman Assessment Battery for Children (KABC) or Wechsler Intelligence Scale for Children, Fourth Edition (WISC-IV) and Wechsler Adult Intelligence Scale, Fourth Edition (WAIS-IV) were performed. RESULTS: Patients with spina bifida show numerous brain malformations, always present for SBA but rarely for SBO. The most frequent brain malformations in SBA included abnormal corpus callosum (69%), hypoplastic pons (50%), and hypoplastic mesencephalon (20%). Cognitive total IQ scores were below average in 44% (KABC) to 49% (WISC-IV) of children with SBA, while almost all children with SBO scored at least average. Stenogyria (p=0.006), pons (p=0.003), and mesencephalon hypoplasia (p=0.01) correlated with lower total IQ score and verbal comprehension. Various brain malformations correlate significantly with several cognitive domains, while lesion level only correlates with processing speed. INTERPRETATION: IQ scores were significantly lower in patients with SBA than in patients with SBO. Verbal competence, perceptual reasoning, and working memory were significantly impaired for SBA and correlated with stenogyria and abnormalities of the midbrain and corpus callosum. WHAT THIS PAPER ADDS: Brain malformations occur more frequently in spina bifida aperta (SBA) than in spina bifida occulta (SBO). Cognitive impairment is less frequent in SBO. Hydrocephalus, stenogyria, midbrain, and corpus callosum abnormalities are associated with lower cognitive function. Difference in prognosis in SBO versus SBA can alter prenatal counselling.

Early Onset, Long Illness Duration, Epilepsy Type, and Polypharmacy Have an Adverse Effect on Psychosocial Outcome in Children with Epilepsy.

Epilepsy is often associated with psychosocial comorbidity and this can be more disabling than the seizure activity. Still, these associated conditions are often underdiagnosed and therefore not sufficiently treated. We studied a large pediatric cohort of 371 patients with epilepsy to identify factors associated with negative outcome. We found that patients with early-onset epilepsy, epilepsy of known etiology, and polypharmacy were the most likely to display cognitive impairment. Behavioral problems were particularly prevalent in patients with an epilepsy duration ≥ 5 years. Similarly, early-onset epilepsy, long illness duration, epilepsy of known etiology, and polypharmacy had an adverse effect on school placement and/or social contact. With polypharmacy being the only potentially modifiable factor, it is important to balance between benefits and adverse effects of antiepileptic drugs and consider alternative therapy options in selected patients such as epilepsy surgery, vagal nerve stimulation, and ketogenic diet early-on.

Age-specific occurrence of pathological fractures in patients with spina bifida.

Pathological fractures (PFs) are common in patients with spina bifida. However, most previous studies refer to the overall fracture rate and largely neglecting putative age-dependent aspects. The aim of this retrospective study was to characterize patterns of fracture occurrence in childhood. In a retrospective study, we identified PF, all in the lower limbs, in 13% of 210 patients with spina bifida aperta. We further identified a bimodal frequency distribution of pathological fractures, with peaks at 1-5 and 10-12 years. We could thereby distinguish two groups of patients: (i) Children with a first fracture before an age of 6 years developed frequently multiple fractures within the following years, but fracture series typically stopped by 6 years-of-age. (ii) Children with a first fracture after the age of 6 years had fewer fractures, but these occurred also in adolescence. PF occurred rarely after the age of 13 years. The age at fracture correlated with the fracture site with 85% of the fractures occurring in the femur in the first five years of life and an increased frequency of tibia and foot fractures later in life. While, overall high lesion levels and preceding immobilizing events were risk factors for PF, femur fractures in children under 6 years-of-age occurred independent of their lesion level, and the age at verticalization did not correlate with PF rates.Conclusion: Based on these findings, standardized and effective preventive physiotherapeutic and/or pharmacological interventions to tackle PF in spina bifida need to consider age-specific differences in occurrence and reoccurrence of fractures.What is Known:• Pathological fractures are common in patients with spina bifida aperta, and associated risk factors include high lesion level, immobilization and low bone density.What is New:• We first report a bimodal frequency distribution of pathological fractures in childhood (first peak 1-5 years, second peak 10-12 years) and link early-onset fracture occurrence with the risk of multiple fractures arise in a short time period but a the chance of self-limitation of fracture series within a few years.• We show that femur fractures in children under 6 years-of-age occurred independent of their lesion level, and the age at verticalization did not correlate with PF rates.• We further link the age-dependent occurrence pattern with the risk of further fractures and with the chance of self-limitation of fracture series. The earlier a first fracture occurs, the more probable multiple fractures arise in a short time period. Nevertheless, early fracture series are often self-limiting within a few years.• Femur fractures in children under 6 years-of-age occurred independent of their lesion level, and the age at verticalization did not correlate with PF rates.• Based on these findings, physiotherapeutic and/or pharmaceutical concepts need to be developed in an age-adapted manner and in consideration of the potential self-limiting nature of fracture series.

De novo mutation in ELOVL1 causes ichthyosis, acanthosis nigricans, hypomyelination, spastic paraplegia, high frequency deafness and optic atrophy.

BACKGROUND: Very long-chain fatty acids (VLCFAs) are essential for functioning of biological membranes. ELOVL fatty acid elongase 1 catalyses elongation of saturated and monounsaturated C22-C26-VLCFAs. We studied two patients with a dominant ELOVL1 mutation. Independently, Kutkowska-Kazmierczak et al. had investigated the same patients and found the same mutation. We extended our study towards additional biochemical, functional, and therapeutic aspects. METHODS: We did mutation screening by whole exome sequencing. RNA-sequencing was performed in patient and control fibroblasts. Ceramide and sphingomyelin levels were measured by LC-MS/MS. ELOVL1 activity was determined by a stable isotope-labelled [13C]malonyl-CoA elongation assay. ELOVL1 expression patterns were investigated by immunofluorescence, in situ hybridisation and RT-qPCR. As treatment option, we investigated VLCFA loading of fibroblasts. RESULTS: Both patients carried an identical heterozygous de novo ELOVL1 mutation (c.494C>T, NM_001256399; p.S165F) not deriving from a founder allele. Patients suffered from epidermal hyperproliferation and increased keratinisation (ichthyosis). Hypomyelination of the central white matter explained spastic paraplegia and central nystagmus, while optic atrophy was causative for reduction of peripheral vision and visual acuity. The mutation abrogated ELOVL1 enzymatic activity and reduced ≥C24 ceramides and sphingomyelins in patient cells. Fibroblast loading with C22:0-VLCFAs increased C24:0-ceramides and sphingomyelins. We found competitive inhibition for ceramide and sphingomyelin synthesis between saturated and monounsaturated VLCFAs. Transcriptome analysis revealed upregulation of modules involved in epidermal development and keratinisation, and downregulation of genes for neurodevelopment, myelination, and synaptogenesis. Many regulated genes carried consensus proliferator-activated receptor (PPAR)α and PPARγ binding motifs in their 5'-regions. CONCLUSION: A dominant ELOVL1 mutation causes a neuro-ichthyotic disorder possibly amenable to treatment with PPAR-modulating drugs.

T7 RNA polymerase non-specifically transcribes and induces disassembly of DNA nanostructures.

The use of proteins that bind and catalyze reactions with DNA alongside DNA nanostructures has broadened the functionality of DNA devices. DNA binding proteins have been used to specifically pattern and tune structural properties of DNA nanostructures and polymerases have been employed to directly and indirectly drive structural changes in DNA structures and devices. Despite these advances, undesired and poorly understood interactions between DNA nanostructures and proteins that bind DNA continue to negatively affect the performance and stability of DNA devices used in conjunction with enzymes. A better understanding of these undesired interactions will enable the construction of robust DNA nanostructure-enzyme hybrid systems. Here, we investigate the undesired disassembly of DNA nanotubes in the presence of viral RNA polymerases (RNAPs) under conditions used for in vitro transcription. We show that nanotubes and individual nanotube monomers (tiles) are non-specifically transcribed by T7 RNAP, and that RNA transcripts produced during non-specific transcription disassemble the nanotubes. Disassembly requires a single-stranded overhang on the nanotube tiles where transcripts can bind and initiate disassembly through strand displacement, suggesting that single-stranded domains on other DNA nanostructures could cause unexpected interactions in the presence of viral RNA polymerases.

Shear-Thinning Viscous Materials for Subconjunctival Injection of Microparticles.

While drug-loaded microparticles (MPs) can serve as drug reservoirs for sustained drug release and therapeutic effects, needle clogging by MPs poses a challenge for ocular drug delivery via injection. Two polymers commonly used in ophthalmic procedures-hyaluronic acid (HA) and methylcellulose (MC)-have been tested for their applicability for ocular injections. HA and MC were physically blended with sunitinib malate (SUN)-loaded PLGA MPs for subconjunctival (SCT) injection into rat eyes. The HA and MC viscous solutions facilitated injection through fine-gauged needles due to their shear-thinning properties as shown by rheological characterizations. The diffusion barrier presented by HA and MC reduced burst drug release and extended overall release from MPs. The significant level of MP retention in the conjunctiva tissue post-operation confirmed the minimal leakage of MPs following injection. The safety of HA and MC for ocular applications was demonstrated histologically.

Experience in shunt management on revision free survival in infants with myelomeningocele.

OBJECTIVE: Depending on the etiology of hydrocephalus in childhood, the shunt therapy still remains challenging due to frequent shunt complications leading to possible revisions such as shunt infection or shunt malfunction. In myelomeningocele (MMC) patients who often require shunt therapy, higher revisions rates were reported. In a single-center retrospective study, experiences on shunt regimen on hydrocephalus associated with MMC are presented. METHODS: Data of 160 infant hydrocephalus cases younger than 1 year of age at the time of implantation were retrospectively reviewed from the hospital database. These patients received an adjustable differential pressure valve with gravitational unit and antibiotic impregnated catheters as a primary or secondary implant during the time period of April 2007 to July 2015. The subgroup of infants cases with MMC (n = 44; age 50.6 ± 80.6 days) were compared to the remaining cohort of other hydrocephalus etiology (control group). The shunt and valve revision free survival rates were recorded until July 2017. RESULTS: During the mean follow-up of 48.7 ± 19.2 (7-114) months, the shunt revision free survival was 87% at 1 year and 49% at 60 months in the MMC cohort. The control group showed a shunt survival rate of 68% at 1 year and 39% at 60 months. Similarly, the valve revision free survival rate showed a significant higher rate of 92% at 1 year and 69% at 60 months in the MMC group compared to the control group (75% at 1 year and 51% at 60 months; p < 0.05). During the entire follow-up period, 37% of the MMC infants underwent a revision operation in contrast to the control group of 40%. CONCLUSION: The presented shunt strategy showed improved revision free survival rates in infants with a MMC-related hydrocephalus in comparison to other etiologies of hydrocephalus in infants, which might relate to infection prophylaxis and high drainage resistance integrated in the shunt system.

Critical illness myopathy and GLUT4: significance of insulin and muscle contraction.

RATIONALE: Critical illness myopathy (CIM) has no known cause and no treatment. Immobilization and impaired glucose metabolism are implicated. OBJECTIVES: We assessed signal transduction in skeletal muscle of patients at risk for CIM. We also investigated the effects of evoked muscle contraction. METHODS: In a prospective observational and interventional pilot study, we screened 874 mechanically ventilated patients with a sepsis-related organ-failure assessment score greater than or equal to 8 for 3 consecutive days in the first 5 days of intensive care unit stay. Thirty patients at risk for CIM underwent euglycemic-hyperinsulinemic clamp, muscle microdialysis studies, and muscle biopsies. Control subjects were healthy. In five additional patients at risk for CIM, we performed corresponding analyses after 12-day, daily, unilateral electrical muscle stimulation with the contralateral leg as control. MEASUREMENTS AND MAIN RESULTS: We performed successive muscle biopsies and assessed systemic insulin sensitivity and signal transduction pathways of glucose utilization at the mRNA and protein level and glucose transporter-4 (GLUT4) localization in skeletal muscle tissue. Skeletal muscle GLUT4 was trapped at perinuclear spaces, most pronounced in patients with CIM, but resided at the sarcolemma in control subjects. Glucose metabolism was not stimulated during euglycemic-hyperinsulinergic clamp. Insulin signal transduction was competent up to p-Akt activation; however, p-adenosine monophosphate-activated protein kinase (p-AMPK) was not detectable in CIM muscle. Electrical muscle stimulation increased p-AMPK, repositioned GLUT4, locally improved glucose metabolism, and prevented type-2 fiber atrophy. CONCLUSIONS: Insufficient GLUT4 translocation results in decreased glucose supply in patients with CIM. Failed AMPK activation is involved. Evoked muscle contraction may prevent muscle-specific AMPK failure, restore GLUT4 disposition, and diminish protein breakdown. Clinical trial registered with http://www.controlled-trials.com (registration number ISRCTN77569430).

Early type II fiber atrophy in intensive care unit patients with nonexcitable muscle membrane.

OBJECTIVE: Intensive care unit-acquired weakness indicates increased morbidity and mortality. Nonexcitable muscle membrane after direct muscle stimulation develops early and predicts intensive care unit-acquired weakness in sedated, mechanically ventilated patients. A comparison of muscle histology at an early stage in intensive care unit-acquired weakness has not been done. We investigated whether nonexcitable muscle membrane indicates fast-twitch myofiber atrophy during the early course of critical illness. DESIGN: Prospective observational study. SETTING: Two intensive care units at Charité University Medicine, Berlin. PATIENTS: Patients at increased risk for development of intensive care unit-acquired weakness, indicated by Sepsis-related Organ Failure Assessment scores ≥8 on 3 of 5 consecutive days within their first week in the intensive care unit. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Electrophysiological compound muscle action potentials after direct muscle stimulation and muscle biopsies were obtained at median days 7 and 5, respectively. Patients with nonexcitable muscle membranes (n = 15) showed smaller median type II cross-sectional areas (p < .05), whereas type I muscle fibers did not compared with patients with preserved muscle membrane excitability (compound muscle action potentials after direct muscle stimulation ≥3.0 mV; n = 9). We also observed decreased mRNA transcription levels of myosin heavy chain isoform IIa and a lower densitometric ratio of fast-to-slow myosin heavy chain protein content. CONCLUSION: We suggest that electrophysiological nonexcitable muscle membrane predicts preferential type II fiber atrophy in intensive care unit patients during early critical illness.

Relationship between cerebral palsy severity and cognition, aids and education.

BACKGROUND: Cerebral palsy (CP) refers to a non-progressive permanent lesion of the developing brain, which can manifest with motor function disability and various comorbidities and complications. However, there is little data on the correlation between motor and mental function in CP, as cognitive assessments are rarely the main focus of studies on children with CP. METHODS: We studied a large cohort of 381 children and adolescents with CP. We analyzed the relationship between severity of CP and the presence of developmental disturbances (motor, motor-linguistic, global) including cognition, the number of aids and education. RESULTS: We found a strong correlation between the severity of CP according to the Gross Motor Function Classification System (GMFCS) and developmental disturbances. In line with this finding, the number of aids per individual also correlated significantly with CP severity and the extent of developmental disturbance. Going beyond the number of aids most patients already received special education in kindergarten. Later, the type of schooling correlated significantly with severity of CP and developmental disturbance. While developmental disturbance and cognition correlated, this was not the case for CP severity and cognition. The latter indicates a wide range in individual manifestation and resources. CONCLUSIONS: Our data underline that cognition does not necessarily correlate with CP severity. Thus, in addition to the evaluation and treatment of motor deficits, cognitive assessment should be offered early-on to improve patient-centered counselling and support with respect to appropriate education.

Standard values for MRI brain biometry throughout the first year of life.

BACKGROUND: Brain structures in the infant brain are investigated reliably using cranial magnetic resonance imaging. However, the lack of quantitative standard values for various brain regions results in data interpretation that is often subjective or based on small patient cohorts. The aim of this study was to create simple linear measurements to assess brain structures in infancy. METHODS: We assessed cranial magnetic resonance imaging sessions of 131 children without intracerebral pathology retrospectively for size of various brain structures throughout the first year of life. RESULTS: Standard values for the size and the growth rate of 14 brain structures including lateral ventricles, frontal subarachnoid space, pons, medulla oblongata, cerebellar vermis, pituitary gland, optical nerve, corpus callosum and the tegmentovermian angle were defined. CONCLUSION: Our study offers reference values for the biometric assessment of the infant brain. Especially in children with multiple brain malformations, it is essential to know the normal absolute and relative size of brain structures.

Clinical Phenotype of Cerebral Palsy Depends on the Cause: Is It Really Cerebral Palsy? A Retrospective Study.

Cerebral palsy is the most common motor disability in childhood. Still, the precise definition in terms of causes and timing of the brain damage remains controversial. Several studies examine the clinical phenotype of cerebral palsy types. The aim of our study was to determine to what extent the clinical phenotype of cerebral palsy patients depends on the underlying cause. We retrospectively evaluated the clinical phenotype, abnormalities during pregnancy, and cerebral palsy cause of 384 patients, treated at Charité-Medicine University, between 2015 and 2017. The cause of cerebral palsy was identified in 79.9% of cases. Causes prior to the perinatal period were, compared to perinatal brain damage, associated significantly with different comorbidities. The term cerebral palsy does not describe a single disease but is an umbrella term covering many different diseases. Depending on the cause, a varying clinical phenotype can be found, which offers great potential in terms of individual treatment and preventing comorbidities.

Tuning Morphologies and Reactivities of Hybrid Organic-Inorganic Nanoparticles.

Hybrid nanoparticles (hNPs), or nanoparticles composed of both organic and inorganic components, hold promise for diverse energy and environmental applications due to their ability to stabilize reactive nanomaterials against aggregation, enhancing their ability to pervade tortuous spaces and travel long distances to degrade contaminants in situ. Past studies have investigated the use of polymer or surfactant coatings to stabilize nanomaterials against aggregation. However, fabrication of these materials often requires multiple steps and lacks specificity in the control of their morphologies and reactivities. Here, we demonstrated a method of producing stable hNPs with tunable morphologies by incubating polystyrene nanoparticles formed via Flash NanoPrecipitation with citrate-stabilized gold nanocatalysts. Using this simple fabrication technique, we found that gold adsorption to polystyrene nanoparticles was enabled by the presence of a good solvent for polystyrene. Furthermore, changing process parameters, such as gold incubation time, and molecular parameters, such as polymer molecular weight and end-group functionality, provided control over the resultant nanocatalyst loading and dispersal atop hNPs. We classified these morphologies into three distinct regimes─aggregated, dispersed, or internalized─and we showed that the emergence of these regimes has key implications for controlling reaction rates in applications such as heterogeneous catalysis or groundwater remediation. Specifically, we found that hNPs with gold nanocatalysts embedded below the surfaces of polystyrene nanoparticles exhibited slower bulk catalytic reduction capacity than their disperse, surface-decorated counterparts. Taken together, our work demonstrates a simple way by which hNPs can be fabricated and presents a method to control catalytic reactions using reactive nanomaterials.

Multiscale dynamics of colloidal deposition and erosion in porous media.

Diverse processes-e.g., environmental pollution, groundwater remediation, oil recovery, filtration, and drug delivery-involve the transport of colloidal particles in porous media. Using confocal microscopy, we directly visualize this process in situ and thereby identify the fundamental mechanisms by which particles are distributed throughout a medium. At high injection pressures, hydrodynamic stresses cause particles to be continually deposited on and eroded from the solid matrix-notably, forcing them to be distributed throughout the entire medium. By contrast, at low injection pressures, the relative influence of erosion is suppressed, causing particles to localize near the inlet of the medium. Unexpectedly, these macroscopic distribution behaviors depend on imposed pressure in similar ways for particles of different charges, although the pore-scale distribution of deposition is sensitive to particle charge. These results reveal how the multiscale interactions between fluid, particles, and the solid matrix control how colloids are distributed in a porous medium.

Clinical Outcome of Children With Corpus Callosum Agenesis.

BACKGROUND: Agenesis of the corpus callosum is a rare congenital brain malformation that can be associated with other cerebral malformations and/or underlying genetic causes. Prenatal counseling is hampered due to the lack of reliable long-term data on neurodevelopmental outcome. METHODS: Since 2010, a total of 23 children with agenesis of the corpus callosum (mean age 3.8 years, range 0.7 to 9.7 years) were registered in our ACC outpatient clinic and diagnosed in a standardized manner; the data were analyzed retrospectively. Prenatal and postnatal imaging, associated malformations, genetic and clinical findings, and psychological testing (Bayley Scales, Kaufman Assessment Battery for Children II, Snijders-Oomen Non-verbal Test, Wechsler Preschool and Primary Scale I-III) were included. The clinical outcome was classified as "normal" (intelligence quotient 85 to 115, unremarkable motor skills), "moderate developmental delay" (intelligence quotient 70 to 85, mild motor abnormalities), and "severe developmental delay" (intelligence quotient less than 70, severe movement disorder). RESULTS: Isolated corpus callosum malformation was diagnosed in 15 of 23 (65%), associated cerebral malformations in four of 23 (17%), and associated cerebral malformations plus intracranial cyst in four of 23 (17%) children. Prenatal diagnosis changed in nine of 23 (39%) cases. Overall, a normal outcome or moderate or severe developmental delay was present in 15 of 23 (65%) or five of 23 (22%) or three of 23 (13%) children, respectively. Also six of eight children with associated cerebral malformations showed normal outcome. CONCLUSION: Our findings support the notion that developmental outcome is favorable in about two-thirds of children with prenatally diagnosed agenesis of corpus callosum. However, the individual outcome in children with agenesis of corpus callosum is difficult to predict. Even children with correctly characterized phenotypes show a variety of outcomes, making prenatal counseling challenging.

Reconfiguring DNA Nanotube Architectures via Selective Regulation of Terminating Structures.

Molecular assemblies inside cells often undergo structural reconfiguration in response to stimuli to alter their function. Adaptive reconfiguration of cytoskeletal networks, for example, enables cellular shape change, movement, and cargo transport and plays a key role in driving complex processes such as division and differentiation. The cellular cytoskeleton is a self-assembling polymer network composed of simple filaments, so reconfiguration often occurs through the rearrangement of its component filaments' connectivities. DNA nanotubes have emerged as promising building blocks for constructing programmable synthetic analogs of cytoskeletal networks. Nucleating seeds can control when and where nanotubes grow, and capping structures can bind nanotube ends to stop growth. Such seeding and capping structures, collectively called termini, can organize nanotubes into larger architectures. However, these structures cannot be selectively activated or inactivated in response to specific stimuli to rearrange nanotube architectures, a key property of cytoskeletal networks. Here, we demonstrate how selective regulation of the binding affinity of DNA nanotube termini for DNA nanotube monomers or nanotube ends can direct the reconfiguration of nanotube architectures. Using DNA hybridization and strand displacement reactions that specifically activate or inactivate four orthogonal nanotube termini, we demonstrate that nanotube architectures can be reconfigured by selective addition or removal of distinct termini. Finally, we show how terminus activation could be a sensitive detector and amplifier of a DNA sequence signal. These results could enable the development of adaptive and multifunctional materials or diagnostic tools.