Correction: Ankyrin-G regulates forebrain connectivity and network synchronization via interaction with GABARAP.

In the original version of this article, affiliation 3 was given as: "Division of Life Sciences, State Key Laboratory of Molecular Neuroscience, Hong Kong, University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China". This has now been corrected to: "Division of Life Sciences, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China".Additionally in the 'Data availability' section an incorrect accession code was given. The accession code has now been changed from 'PDB A9X (AnkG:GABARAPL)' to 'PDB 6A9X (AnkG:GABARAP)'.These errors have been corrected in both the PDF and HTML versions of the Article.

Ankyrin-G regulates forebrain connectivity and network synchronization via interaction with GABARAP.

GABAergic circuits are critical for the synchronization and higher order function of brain networks. Defects in this circuitry are linked to neuropsychiatric diseases, including bipolar disorder, schizophrenia, and autism. Work in cultured neurons has shown that ankyrin-G plays a key role in the regulation of GABAergic synapses on the axon initial segment and somatodendritic domain of pyramidal neurons, where it interacts directly with the GABAA receptor-associated protein (GABARAP) to stabilize cell surface GABAA receptors. Here, we generated a knock-in mouse model expressing a mutation that abolishes the ankyrin-G/GABARAP interaction (Ank3 W1989R) to understand how ankyrin-G and GABARAP regulate GABAergic circuitry in vivo. We found that Ank3 W1989R mice exhibit a striking reduction in forebrain GABAergic synapses resulting in pyramidal cell hyperexcitability and disruptions in network synchronization. In addition, we identified changes in pyramidal cell dendritic spines and axon initial segments consistent with compensation for hyperexcitability. Finally, we identified the ANK3 W1989R variant in a family with bipolar disorder, suggesting a potential role of this variant in disease. Our results highlight the importance of ankyrin-G in regulating forebrain circuitry and provide novel insights into how ANK3 loss-of-function variants may contribute to human disease.

Mobilising vitamin D from adipose tissue: The potential impact of exercise.

Vitamin D is lipophilic and accumulates substantially in adipose tissue. Even without supplementation, the amount of vitamin D in the adipose of a typical adult is equivalent to several months of the daily reference nutrient intake (RNI). Paradoxically, despite the large amounts of vitamin D located in adipose tissue, individuals with obesity are often vitamin D deficient according to consensus measures of vitamin D status (serum 25-hydroxyvitamin D concentrations). Thus, it appears that vitamin D can become 'trapped' in adipose tissue, potentially due to insufficient lipolytic stimulation and/or due to tissue dysfunction/adaptation resulting from adipose expansion. Emerging evidence suggests that exercise may mobilise vitamin D from adipose (even in the absence of weight loss). If exercise helps to mobilise vitamin D from adipose tissue, then this could have important ramifications for practitioners and policymakers regarding the management of low circulating levels of vitamin D, as well as chronically low levels of physical activity, obesity and associated health conditions. This perspective led us to design a study to examine the impact of exercise on vitamin D status, vitamin D turnover and adipose tissue vitamin D content (the VitaDEx project). The VitaDEx project will determine whether increasing physical activity (via exercise) represents a potentially useful strategy to mobilise vitamin D from adipose tissue.

Capsaicin reduces PLGA-induced fibrosis by promoting M2 macrophages and suppressing overall inflammatory Response.

Capsaicin reduced poly(lactic-co-glycolic) acid (PLGA)-induced fibrosis by promoting IL-10 secretion and suppressing alpha-smooth muscle actin (α-SMA) expression. The lifetime and efficacy of tissue engineering scaffolds are determined by the foreign body response. In this study, we investigated the in vitro and in vivo effects of capsaicin to reduce biomaterial-induced fibrosis. RAW 264.7 cells cultured on PLGA films with capsaicin responded with significant (p < 0.05) upregulation in M2 markers arginase-1 and IL-10 and downregulation of M1 markers iNOS and IL-12, demonstrating the potential of capsaicin to reduce PLGA-induced inflammation. Subsequent animal studies were conducted where PLGA and capsaicin-embedded PLGA discs were implanted in C57BL/6 mice for 2 and 14 days. Explanted capsaicin-embedded PLGA implants had 40% less collagen than PLGA-only implants. Capsaicin caused a 35% increase in IL-10 which played a key role in suppressing fibrosis. Macrophage phenotype markers in peritoneal cells and adherent cells were unaffected by capsaicin; however, capsaicin suppressed the myofibroblast marker α-SMA in adherent cells by day 14. Overall, our results revealed that capsaicin reduced biomaterial-induced fibrosis and demonstrates that capsaicin has the potential to extend the lifetime of a tissue engineering scaffold when used in long-term drug release applications from hydrophobic biomaterials. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A:2424-2432, 2018.

Lateral Ge Diffusion During Oxidation of Si/SiGe Fins.

This Letter reports on the unusual diffusion behavior of Ge during oxidation of a multilayer Si/SiGe fin. It is observed that oxidation surprisingly results in the formation of vertically stacked Si nanowires encapsulated in defect free epitaxial strained SixGe1-x. High angle annular dark field scanning transmission electron microscopy (HAADF-STEM) shows that extremely enhanced diffusion of Ge occurs along the vertical Si/SiO2 oxidizing interface and is responsible for the encapsulation process. Further oxidation fully encapsulates the Si layers in defect free single crystal SixGe1-x (x up to 0.53), which results in Si nanowires with up to -2% strain. Atom probe tomography reconstructions demonstrate that the resultant nanowires run the length of the fin. We found that the oxidation temperature plays a significant role in the formation of the Si nanowires. In the process range of 800-900 °C, pure strained and rounded Si nanowires down to 2 nm in diameter can be fabricated. At lower temperatures, the Ge diffusion along the oxidizing Si/SiO2 interface is slow, and rounding of the nanowire does not occur, while at higher temperatures, the diffusivity of Ge into Si is sufficient to result in dilution of the pure Si nanowire with Ge. The use of highly selective etchants to remove the SiGe could provide a new pathway for the creation of highly controlled vertically stacked nanowires for gate all around transistors.

AAV1/2-mediated BDNF gene therapy in a transgenic rat model of Huntington's disease.

Reduced expression and disrupted corticostriatal transportation of brain-derived neurotrophic factor (BDNF) is proposed to contribute to the selective vulnerability of medium spiny striatal projection neurons (MSNs) in Huntington's disease (HD). We have previously demonstrated that BDNF overexpression in the quinolinic acid lesioned rat striatum attenuates motor impairment and reduces the extent of MSN cell loss. To further investigate the potential therapeutic properties of BDNF for HD, the current study examines the effect of bilateral AAV1/2-mediated BDNF expression in the striatum of a transgenic rat model of HD. Transfer of the BDNF gene to striatal neurons using an AAV1/2 serotype vector enhanced BDNF protein levels in the striatum. Bilateral BDNF expression attenuated the impairment of both motor and cognitive function when compared with AAV1/2-vehicle- or YFP-treated transgenic HD rats. Interestingly, a gender effect was apparent with female transgenic HD rats exhibiting less functional impairment than males. Quantification of NeuN and DARRP32 immunoreactivity and striatal volume revealed limited disease phenotype between wild type and transgenic HD animals. However, AAV1/2-BDNF-treated transgenic HD rats showed evidence of greater striatal volume and increased NeuN+ cell numbers compared with wild-type vehicle- and AAV1/2-vehicle- or YFP-treated transgenic HD rats. We propose BDNF holds considerable therapeutic potential for alleviating behavioral dysfunction and neuronal degeneration in HD, with further work required to examine the role of BDNF-TrkB signaling and the preservation of axonal and synaptic function.

Vitamin D binding protein genotype is associated with plasma 25OHD concentration in West African children.

Vitamin D is well known for its role in promoting skeletal health. Vitamin D status is determined conventionally by circulating 25-dihydroxyvitamin D (25OHD) concentration. There is evidence indicating that circulating 25OHD concentration is affected by variation in Gc, the gene encoding the vitamin D binding protein (DBP). The composite genotype of two single nucleotide polymorphisms (rs7041 and rs4588) results in different DBP isotypes (Gc1f, Gc1s and Gc2). The protein configurational differences among DBP isotypes affect DBP substrate binding affinity. The aims of this study were to determine 1) Gc variant frequencies in a population from an isolated rural region of The Gambia, West Africa (n=3129) with year-round opportunity for cutaneous vitamin D synthesis and 2) the effects of Gc variants on 25OHD concentration (n=237) in a genetically representative sub-group of children (mean (SD) age: 11.9 (4.8) years). The distribution of Gc variants was Gc1f: 0.86, Gc1s: 0.11 and Gc2: 0.03. The mean (SD) concentration of 25OHD was 59.6 (12.9) nmol/L and was significantly higher in those homozygous for Gc1f compared to other Gc variants (60.7 (13.1) vs. 56.6 (12.1) nmol/L, P=0.03). Plasma 25OHD and 1,25(OH)2D concentration was significantly associated with parathyroid hormone in Gc1f-1f but not in the other Gc variants combined. This study demonstrates that different Gc variants are associated with different 25OHD concentrations in a rural Gambian population. Gc1f-1f, thought to have the highest affinity for 25OHD, had the highest 25OHD concentration compared with lower affinity Gc variants. The considerable difference in Gc1f frequency observed in Gambians compared with other non-West African populations and associated differences in plasma 25OHD concentration, may have implications for the way in which vitamin D status should be interpreted across different ancestral groups.

Predictors of 25(OH)D half-life and plasma 25(OH)D concentration in The Gambia and the UK.

UNLABELLED: Predictors of 25(OH)D3 half-life were factors associated with vitamin D metabolism, but were different between people in The Gambia and the UK. Country was the strongest predictor of plasma 25(OH)D concentration, probably as a marker of UVB exposure. 25(OH)D3 half-life may be applied as a tool to investigate vitamin D expenditure. INTRODUCTION: The aim of this study was to investigate predictors of 25(OH)D3 half-life and plasma 25(OH)D concentration. METHODS: Plasma half-life of an oral tracer dose of deuterated-25(OH)D3 was measured in healthy men aged 24-39 years, resident in The Gambia, West Africa (n = 18) and in the UK during the winter (n = 18), countries that differ in calcium intake and vitamin D status. Plasma and urinary markers of vitamin D, calcium, phosphate and bone metabolism, nutrient intakes and anthropometry were measured. RESULTS: Normally distributed data are presented as mean (SD) and non-normal data as geometric mean (95% CI). Gambian compared to UK men had higher plasma concentrations of 25(OH)D (69 (13) vs. 29 (11) nmol/L; P < 0.0001); 1,25(OH)2D (181 (165, 197) vs. 120 (109, 132) pmol/L; P < 0.01); and parathyroid hormone (PTH) (50 (42, 60) vs. 33 (27, 39); P < 0.0001). There was no difference in 25(OH)D3 half-life (14.7 (3.5) days vs. 15.6 (2.5) days) between countries (P = 0.2). In multivariate analyses, 25(OH)D, 1,25(OH)2D, vitamin D binding protein and albumin-adjusted calcium (Caalb) explained 79% of variance in 25(OH)D3 half-life in Gambians, but no significant predictors were found in UK participants. For the countries combined, Caalb, PTH and plasma phosphate explained 39 % of half-life variability. 1,25(OH)2D, weight, PTH and country explained 81% of variability in 25(OH)D concentration; however, country alone explained 74%. CONCLUSION: Factors known to affect 25(OH)D metabolism predict 25(OH)D3 half-life, but these differed between countries. Country predicted 25(OH)D, probably as a proxy measure for UVB exposure and vitamin D supply. This study supports the use of 25(OH)D half-life to investigate vitamin D metabolism.

25(OH)D2 half-life is shorter than 25(OH)D3 half-life and is influenced by DBP concentration and genotype.

CONTEXT: There is uncertainty over the equivalence of vitamins D2 and D3 to maintain plasma 25-hydroxyvitamin D (25(OH)D). OBJECTIVE: The objective of the study was to compare the plasma half-lives of 25(OH)D2 and 25(OH)D3 in two distinct populations with different dietary calcium intake and 25(OH)D status. PARTICIPANTS: Healthy men (aged 24 and 39 y), resident in The Gambia (n = 18) or the United Kingdom (n = 18) participated in the study. INTERVENTIONS: The intervention included an oral tracer dose of deuterated-25(OH)D2 and deuterated-25(OH)D3 (both 40 nmol). Blood samples were collected over 33 days. MAIN OUTCOME MEASURES: 25(OH)D2 and 25(OH)D3 plasma half-lives, concentrations of 25(OH)D, and vitamin D binding protein (DBP) and DBP genotypes were measured. RESULTS: 25(OH)D2 half-life [mean (SD)] [13.9 (2.6) d] was shorter than 25(OH)D3 half-life [15.1 (3.1) d; P = .001] for countries combined, and in Gambians [12.8 (2.3) d vs 14.7 (3.5) d; P < .001], but not in the United Kingdom [15.1 (2.4) d vs 15.6 (2.5) d; P = .3]. 25(OH)D concentration was 69 (13) and 29 (11) nmol/L (P < .0001), and the DBP concentration was 259 (33) and 269 (23) mg/L (P = .4) in The Gambia and United Kingdom, respectively. Half-lives were positively associated with plasma DBP concentration for countries combined [25(OH)D2 half-life: regression coefficient (SE) 0.03 (0.01) d per 1 mg/L DBP, P = .03; 25(OH)D3 half-life: 0.04 (0.02) d, P = .02] and in Gambians [25(OH)D2 half-life: 0.04 (0.01) d; P = .02; 25(OH)D3 half-life: 0.06 (0.02) d, P = .01] but not in UK participants. The DBP concentration × country interactions were not significant. DBP Gc1f/1f homozygotes had shorter 25(OH)D2 half-lives compared with other combined genotypes (P = .007) after correction for country. CONCLUSIONS: 25(OH)D2 half-life was shorter than 25(OH)D3 half-life, and half-lives were affected by DBP concentration and genotype. The stable isotope 25(OH)D half-life measurements provide a novel tool to investigate vitamin D metabolism and vitamin D expenditure and aid in the assessment of vitamin D requirements.

Kinetics and morphological instabilities of stressed solid-solid phase transformations.

An atomistic model of the growth kinetics of stressed solid-solid phase transformations is presented. Solid phase epitaxial growth of (001) Si was used for comparison of new and prior models with experiments. The results indicate that the migration of crystal island ledges in the growth interface may involve coordinated atomic motion. The model accounts for morphological instabilities during stressed solid-solid phase transformations.

A stable isotope method for the simultaneous measurement of vitamin K1 (phylloquinone) kinetics and absorption.

OBJECTIVES: To measure uptake and disposal kinetics and absolute absorption of vitamin K(1) using two stable isotope-labelled forms of vitamin K(1). SUBJECTS: Ten subjects (nine women and one man) aged between 22 and 31 years, with a mean (+/-standard deviation) body mass index of 22.5+/-2.4 kg/m(2). Subjects took capsules containing 3 microg of methyl-(13)C vitamin K(1), three times a day for six days to reach a steady state for plasma vitamin K(1) isotopic enrichment. On day seven, subjects were given an intravenous dose of Konakion MM to measure disposal kinetics and at the same time, a capsule containing 4 microg of ring-D(4) vitamin K(1) to measure absorption. Plasma vitamin K(1) concentration was measured by high-performance liquid chromatography and isotopic composition by gas chromatography mass spectrometry. RESULTS: The disposal kinetics of the intravenous dose of vitamin K(1) were resolved into two exponentials with half-times of 0.22 (+/-0.14) and 2.66 (+/-1.69) h. Absorption of oral, deuterated vitamin K(1) was 13 (+/-9)%. CONCLUSIONS: Two-compartmental kinetic parameters observed in this study are similar to those obtained previously using radioactive tracers, but there may be additional slow-turnover body pools acting as stores of vitamin K(1). The kinetic parameters determined from the intravenous dose allowed determination of the absolute absorption of vitamin K(1) from a bolus oral dose.

3-D analysis of semiconductor dopant distributions in a patterned structure using LEAP.

This work presents the first 3-D analysis of lateral dopant diffusion in a patterned structure using a pulsed laser-assisted local electrode atom probe (LEAP). A structure similar to a device channel was created for this work by performing a 3 keV, 1 x 10(15) cm(-2) As+ implant on a poly-Si line patterned wafer with 70 nm line width and 200 nm line pitch. The wafer was subsequently annealed at 950 degrees C for 1s. LEAP samples were made using a site-selective in-situ focused ion beam (FIB) process. The results from LEAP analysis were then compared with high-resolution transmission electron microscopy (HRTEM) and Florida object-oriented process simulator (FLOOPS) results. Good structural agreement was found between the LEAP and HRTEM results. Several 1-D As concentration profiles extracted from the LEAP data were also found to be in good agreement with FLOOPS process simulation results. These profiles also represent for the first time that results from a 3-D process simulator have been able to be confirmed experimentally using a single sample.

Dendrimer-grafted cell adhesion peptide-modified PDMS.

Surface concentration of cell adhesion peptides is thought to play a role in the interactions between biomaterials and cells. The high density of functional groups at the periphery of dendrimers has been exploited in various applications, but their full potential for generating surfaces with high functional group concentrations has not yet been realized. Poly(dimethylsiloxane) elastomers were surface modified with both polyethylene oxide (PEO) and generation 3 diaminobutane dendrimers. PEO and the dendrimers were subsequently used as linker molecules for surface grafting of cell adhesion peptides. ATR-FTIR, X-ray photoelectron spectroscopy, and water contact angle results confirmed the successful attachment of the polymer linkers and peptides. Peptide grafting density was quantified by means of (125)I radiolabeling. Maximum surface peptide grafting density on dendrimer-modified surfaces was twofold greater than the maximum peptide grafting density achieved via the PEO linker. However, vascular endothelial cell adhesion was significantly greater on surfaces modified with the PEO linker, presumably due to the highly flexible PEO spacer making the peptide more accessible for binding with the cell surface receptors. These results suggest that, although peptide surface density may be important, optimizing surface density may not be sufficient for improving biological interactions.

Use of CultureSwab Plus swabs with Amies gel agar for testing of naris specimens with the GeneOhm MRSA assay.

The GeneOhm MRSA assay detects nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA). We compared the use of seeded swabs with liquid Stuart's medium and that of seeded swabs with Amies gel for the assay. Overall, the swabs with liquid Stuart's medium detected significantly greater numbers of MRSA than the swabs with Amies gel (P = 0.0003).

Hip arthroscopy in athletes.

The limited data (n = 42) and diverse pathology within this study make statistical analysis difficult, although the observations are still meaningful. Diagnostic arthroscopy has defined elusive causes of disabling hip pain in an athletic population including occult labral and chondral damage and rupture of the ligamentum teres. Operative arthroscopy has been effective in reducing the symptoms associated with many of these forms of pathology. For more evident causes of hip pain, such as loose bodies or impinging osteophytes, arthroscopy offers an excellent alternative to traditional open techniques. This study has defined that many intraarticular disorders initially may go unrecognized. The benefit of earlier diagnosis seems intuitive and may minimize extraneous investigative studies, but there are a few caveats. First, various forms of extraarticular pathology (e.g., muscle strains) far outnumber intraarticular injuries and thus the temptation for an extensive intraarticular work up for every hip injury should be avoided. Second, as mentioned, does earlier diagnosis always mean early intervention? There is much that we may not fully understand regarding the natural history of many of these intraarticular disorders that we are only now learning to diagnose.

Elbow arthroscopy for neglected osteochondritis dissecans of the capitellum.

We reviewed results of elbow arthroscopy for neglected osteochondritis dissecans (OCD) of the capitellum. Of more than 140 patients having elbow arthroscopy at our institution, 10 patients (11 elbows) had OCD of the capitellum and fulfilled inclusion criteria. Criteria included symptoms of at least 2 years' duration, loss of motion for at least 6 months, or radiographic evidence of secondary degenerative changes. One patient was lost to follow-up. The remaining 9 (10 elbows) were male patients with a median age of 20 years (range, 15 to 58 years). Follow-up averaged 4.6 years (range, 2 to 8 years). Using a 100-point system, postoperative elbow scores averaged 92 (range, 55 to 100). All patients returned to preoperative activities, though only 8 of 10 believed that surgery resulted in improvement. Elbow arthroscopy for neglected OCD can result in functional improvement. However, results are not as good as those reported with earlier intervention.

The effects of signal salience and caffeine on performance, workload, and stress in an abbreviated vigilance task.

In 2 experiments, a 12-min computerized vigilance task was demonstrated to reproduce the vigilance decrement, high workload (NASA-TLX), and stressful character (Dundee Stress State Questionnaire) of vigilance tasks lasting 30 min or more. In Experiment 1, the abbreviated task was also shown to duplicate the signal salience effect, a major finding associated with long-duration vigilance tasks. Moreover, Experiment 2 showed that performance on the abbreviated task can be enhanced by caffeine - a drug that benefits long-duration tasks. This enhancement effect was limited to performance, however, suggesting that caffeine influences factors that control signal detection but not those that control task-induced stress. The results parallel those obtained with long-duration tasks and support a resource-depletion model of the vigilance decrement. The abbreviated task might be useful in situations in which long-duration tasks are precluded (e.g., performance assessment batteries, neuropsychological testing, and brain imaging).

Prospective analysis of hip arthroscopy with 2-year follow-up.

PURPOSE: Numerous indications, but little outcome data, have been reported for hip arthroscopy. The purpose of this prospective study is to report the 2-year results of hip arthroscopy performed on a consecutive series of patients for a variety of disorders. TYPE OF STUDY: Case series. MATERIALS AND METHODS: There were 38 procedures performed on 35 patients who have achieved 2-year follow-up. All patients were assessed with a modified Harris hip score (pain and function) preoperatively and postoperatively at 1, 3, 6, 12, and 24 months or until a subsequent procedure was performed. Variables studied included age, sex, diagnosis, duration of symptoms, onset of symptoms, center-edge angle, Workers' Compensation, and pending litigation. RESULTS: Follow-up was obtained on all patients. The median score improved from 57 to 85 points. This included 10 cases (9 patients) who underwent a subsequent procedure at an average of 10 months (6 total hip arthroplasty, 1 core decompression, 3 second arthroscopy) with an index score of 54 compared with 52 at the time of the second procedure. The median improvement for the following diagnoses was: loose body (34), labral lesion (27), synovitis (26), chondral injury (18), arthritis (14), and avascular necrosis (-11). Of the variables studied, the most statistically significant finding was that older men with longer duration of symptoms did worse. Two complications occurred in 1 patient: partial neuropraxia of the lateral femoral cutaneous nerve and focal myositis ossificans along the anterior portal tract. CONCLUSIONS: Hip arthroscopy can be performed for a variety of conditions (except end-stage avascular necrosis) with reasonable expectations of success and an acceptable complication rate. This is the first report to quantitate the results of hip arthroscopy for a heterogeneous population.