Selective Ablation of Megalin in the Retinal Pigment Epithelium Results in Megaophthalmos, Macromelanosome Formation and Severe Retina Degeneration

PURPOSE: Mutations in the megalin-encoding gene, LRP2, cause high myopia as seen in patients suffering from Donnai-Barrow/facio-oculo-acoustico-renal syndrome. Megalin is present in both the nonpigmented epithelium of the ciliary body and in the RPE. In this study, we set out to establish an animal model to study the mechanisms underlying the ocular phenotype and to establish if high myopia/megaophthalmos is induced by postnatal megalin-deficiency in the RPE. METHODS: Postnatal RPE-specific deletion of megalin was generated by crossing mice bearing a homozygous loxP-flanked Lrp2 allele with transgenic mice expressing the Cre recombinase driven by the BEST1 promotor. The model was investigated by immunohistologic techniques, and transmission electron microscopy. RESULTS: Mice with postnatal RPE-specific loss of megalin developed a megaophthalmos phenotype with dramatic increase in ocular size and severe retinal thinning associated with compromised vision. This phenotype was present at postnatal day 14, indicating rapid development in the period from onset of BEST1 promotor activity at postnatal day 10. Additionally, RPE melanosomes exhibited abnormal size and morphology, suggested by electron tomography to be caused by fusion events between multiple melanosomes. CONCLUSIONS: Postnatal loss of megalin in the RPE induces dramatic and rapid ocular growth and retinal degeneration compatible with the high myopia observed in Donnai-Barrow patients. The morphologic changes of RPE melanosomes, believed to be largely inert and fully differentiated at birth, suggested a continued plasticity of mature melanosomes and a requirement for megalin to maintain their number and morphology

Pulmonary sarcoidosis associated with psoriasis vulgaris: coincidental occurrence or causal association? Case report

BACKGROUND: Sarcoidosis is rarely associated with a distinct disease. One disease infrequently associated with sarcoidosis is psoriasis. CASE PRESENTATION: This case study describes a 38-year-old male, who presented with chest pain, high-grade fever, arthralgias and a skin rash accompanied by bilateral hilar lymphadenopathy on his chest radiograph. Extensive investigations including fiber-optic bronchoscopy with bronchoalveolar lavage and labial and skin biopsies, demonstrated that two distinct clinical entities co-existed in the same patient: pulmonary sarcoidosis and psoriasis vulgaris. Combination therapy for both diseases was applied and the patient was greatly improved. CONCLUSION: This is the first well-documented case of sarcoidosis and psoriasis in the same patient, reported on the basis of safe and widely-used techniques that were not available until fairly recently. These disorders might share common pathogenic mechanisms that could explain their co-existence in the patient

Structural and Functional Deficits in a Neuronal Calcium Sensor-1 Mutant Identified in a Case of Autistic Spectrum Disorder

Neuronal calcium sensor-1 (NCS-1) is a Ca2+ sensor protein that has been implicated in the regulation of various aspects of neuronal development and neurotransmission. It exerts its effects through interactions with a range of target proteins one of which is interleukin receptor accessory protein like-1 (IL1RAPL1) protein. Mutations in IL1RAPL1 have recently been associated with autism spectrum disorders and a missense mutation (R102Q) on NCS-1 has been found in one individual with autism. We have examined the effect of this mutation on the structure and function of NCS-1. From use of NMR spectroscopy, it appeared that the R102Q affected the structure of the protein particularly with an increase in the extent of conformational exchange in the C-terminus of the protein. Despite this change NCS-1(R102Q) did not show changes in its affinity for Ca2+ or binding to IL1RAPL1 and its intracellular localisation was unaffected. Assessment of NCS-1 dynamics indicated that it could rapidly cycle between cytosolic and membrane pools and that the cycling onto the plasma membrane was specifically changed in NCS-1(R102Q) with the loss of a Ca2+ -dependent component. From these data we speculate that impairment of the normal cycling of NCS-1 by the R102Q mutation could have subtle effects on neuronal signalling and physiology in the developing and adult brain

Undergraduate medical research: the student perspective

Background: Research training is essential in a modern undergraduate medical curriculum. Our evaluation aimed to (a) gauge students’ awareness of research activities, (b) compare students’ perceptions of their transferable and research-specific skills competencies, (c) determine students’ motivation for research and (d) obtain students’ personal views on doing research. Methods: Undergraduate medical students (N=317) completed a research skills questionnaire developed by the Centre for Excellence in Teaching and Learning in Applied Undergraduate Research Skills (CETL-AURS) at Reading University. The questionnaire assessed students’ transferable skills, research-specific skills (e.g., study design, data collection and data analysis), research experience and attitude and motivation towards doing research. Results: The majority of students are motivated to pursue research. Graduate entrants and male students appear to be the most confident regarding their research skills competencies. Although all students recognise the role of research in medical practice, many are unaware of the medical research activities or successes within their university. Of those who report no interest in a career incorporating research, a common perception was that researchers are isolated from patients and clinical practice. Discussion: Students have a narrow definition of research and what it entails. An explanation for why research competence does not align more closely with research motivation is derived from students’ lack of understanding of the concept of translational research, as well as a lack of awareness of the research activity being undertaken by their teachers and mentors. We plan to address this with specific research awareness initiatives

Error-Prone ZW Pairing and No Evidence for Meiotic Sex Chromosome Inactivation in the Chicken Germ Line

In the male mouse the X and Y chromosomes pair and recombine within the small pseudoautosomal region. Genes located on the unsynapsed segments of the X and Y are transcriptionally silenced at pachytene by Meiotic Sex Chromosome Inactivation (MSCI). The degree to which MSCI is conserved in other vertebrates is currently unclear. In the female chicken the ZW bivalent is thought to undergo a transient phase of full synapsis at pachytene, starting from the homologous ends and spreading through the heterologous regions. It has been proposed that the repair of the ZW DNA double-strand breaks (DSBs) is postponed until diplotene and that the ZW bivalent is subject to MSCI, which is independent of its synaptic status. Here we present a distinct model of meiotic pairing and silencing of the ZW pair during chicken oogenesis. We show that, in most oocytes, DNA DSB foci on the ZW are resolved by the end of pachytene and that the ZW desynapses in broad synchrony with the autosomes. We unexpectedly find that ZW pairing is highly error prone, with many oocytes failing to engage in ZW synapsis and crossover formation. Oocytes with unsynapsed Z and W chromosomes nevertheless progress to the diplotene stage, suggesting that a checkpoint does not operate during pachytene in the chicken germ line. Using a combination of epigenetic profiling and RNA–FISH analysis, we find no evidence for MSCI, associated with neither the asynaptic ZW, as described in mammals, nor the synaptic ZW. The lack of conservation of MSCI in the chicken reopens the debate about the evolution of MSCI and its driving forces

Oncological outcome and patient satisfaction with skin-sparing mastectomy and immediate breast reconstruction: a prospective observational study

<p>Abstract</p> <p>Background</p> <p>The management of early breast cancer (BC) with skin-sparing mastectomy (SSM) and immediate breast reconstruction (IBR) is not based on level-1 evidence. In this study, the oncological outcome, post-operative morbidity and patients' satisfaction with SSM and IBR using the latissimus dorsi (LD) myocutaneous flap and/or breast prosthesis is evaluated.</p> <p>Methods</p> <p>137 SSMs with IBR (10 bilateral) were undertaken in 127 consecutive women, using the LD flap plus implant (n = 85), LD flap alone (n = 1) or implant alone (n = 51), for early BC (n = 130) or prophylaxis (n = 7). Nipple reconstruction was performed in 69 patients, using the trefoil local flap technique (n = 61), nipple sharing (n = 6), skin graft (n = 1) and Monocryl mesh (n = 1). Thirty patients underwent contra-lateral procedures to enhance symmetry, including 19 augmentations and 11 mastopexy/reduction mammoplasties. A linear visual analogue scale was used to assess patient satisfaction with surgical outcome, ranging from 0 (not satisfied) to 10 (most satisfied).</p> <p>Results</p> <p>After a median follow-up of 36 months (range = 6-101 months) there were no local recurrences. Overall breast cancer specific survival was 99.2%, 8 patients developed distant disease and 1 died of metastatic BC. There were no cases of partial or total LD flap loss. Morbidities included infection, requiring implant removal in 2 patients and 1 patient developed marginal ischaemia of the skin envelope. Chemotherapy was delayed in 1 patient due to infection. Significant capsule formation, requiring capsulotomy, was observed in 85% of patients who had either post-mastectomy radiotherapy (PMR) or prior radiotherapy (RT) compared with 13% for those who had not received RT. The outcome questionnaire was completed by 82 (64.6%) of 127 patients with a median satisfaction score of 9 (range = 5-10).</p> <p>Conclusion</p> <p>SSM with IBR is associated with low morbidity, high levels of patient satisfaction and is oncologically safe for T(is), T1 and T2 tumours without extensive skin involvement.</p

Exploring the relationship between video game expertise and fluid intelligence

Hundreds of millions of people play intellectually-demanding video games every day. What does individual performance on these games tell us about cognition? Here, we describe two studies that examine the potential link between intelligence and performance in one of the most popular video games genres in the world (Multiplayer Online Battle Arenas: MOBAs). In the first study, we show that performance in the popular MOBA League of Legends' correlates with fluid intelligence as measured under controlled laboratory conditions. In the second study, we also show that the age profile of performance in the two most widely-played MOBAs (League of Legends and DOTA II) matches that of raw fluid intelligence. We discuss and extend previous videogame literature on intelligence and videogames and suggest that commercial video games can be useful as 'proxy' tests of cognitive performance at a global population level

Investigation of Atomic Level Patterns in Protein—Small Ligand Interactions

BACKGROUND: Shape complementarity and non-covalent interactions are believed to drive protein-ligand interaction. To date protein-protein, protein-DNA, and protein-RNA interactions were systematically investigated, which is in contrast to interactions with small ligands. We investigate the role of covalent and non-covalent bonds in protein-small ligand interactions using a comprehensive dataset of 2,320 complexes. METHODOLOGY AND PRINCIPAL FINDINGS: We show that protein-ligand interactions are governed by different forces for different ligand types, i.e., protein-organic compound interactions are governed by hydrogen bonds, van der Waals contacts, and covalent bonds; protein-metal ion interactions are dominated by electrostatic force and coordination bonds; protein-anion interactions are established with electrostatic force, hydrogen bonds, and van der Waals contacts; and protein-inorganic cluster interactions are driven by coordination bonds. We extracted several frequently occurring atomic-level patterns concerning these interactions. For instance, 73% of investigated covalent bonds were summarized with just three patterns in which bonds are formed between thiol of Cys and carbon or sulfur atoms of ligands, and nitrogen of Lys and carbon of ligands. Similar patterns were found for the coordination bonds. Hydrogen bonds occur in 67% of protein-organic compound complexes and 66% of them are formed between NH- group of protein residues and oxygen atom of ligands. We quantify relative abundance of specific interaction types and discuss their characteristic features. The extracted protein-organic compound patterns are shown to complement and improve a geometric approach for prediction of binding sites. CONCLUSIONS AND SIGNIFICANCE: We show that for a given type (group) of ligands and type of the interaction force, majority of protein-ligand interactions are repetitive and could be summarized with several simple atomic-level patterns. We summarize and analyze 10 frequently occurring interaction patterns that cover 56% of all considered complexes and we show a practical application for the patterns that concerns interactions with organic compounds

C14ORF39/SIX6OS1 is a constituent of the synaptonemal complex and is essential for mouse fertility

Meiotic recombination generates crossovers between homologous chromosomes that are essential for genome haploidization. The synaptonemal complex is a ‘zipper’-like protein assembly that synapses homologue pairs together and provides the structural framework for processing recombination sites into crossovers. Humans show individual differences in the number of crossovers generated across the genome. Recently, an anonymous gene variant in C14ORF39/SIX6OS1 was identified that influences the recombination rate in humans. Here we show that C14ORF39/SIX6OS1 encodes a component of the central element of the synaptonemal complex. Yeast two-hybrid analysis reveals that SIX6OS1 interacts with the well-established protein synaptonemal complex central element 1 (SYCE1). Mice lacking SIX6OS1 are defective in chromosome synapsis at meiotic prophase I, which provokes an arrest at the pachytene-like stage and results in infertility. In accordance with its role as a modifier of the human recombination rate, SIX6OS1 is essential for the appropriate processing of intermediate recombination nodules before crossover formation.This work was supported by BFU_2014-59307-R, MEIONet and JCyLe (CSI052U16). LGH and NFM are supported by European Social Fund/JCyLe grants (EDU/1083/2013 and EDU/310/2015). ORD is a Sir Henry Dale Fellow jointly funded by the Wellcome Trust and Royal Society (Grant Number 104158/Z/14/Z). RB is funded by DFG (grant Be1168/8-1). AT and ID were supported by DFG grants TO421/8-2 and TO421/6-1, respectively.Peer reviewe