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Abstract Background The TRPV4 gene encodes a calcium-permeable ion-channel that is widely expressed, responds to many different stimuli and participates in an extraordinarily wide range of physiologic processes. Autosomal dominant brachyolmia, spondylometaphyseal dysplasia Kozlowski type (SMDK) and metatropic dysplasia (MD) are currently considered three distinct skeletal dysplasias with some shared clinical features, including short stature, platyspondyly, and progressive scoliosis. Recently, TRPV4 mutations have been found in patients diagnosed with these skeletal phenotypes. Methods and Results We critically analysed the clinical and radiographic data on 26 subjects from 21 families, all of whom had a clinical diagnosis of one of the conditions described above: 15 with MD; 9 with SMDK; and 2 with brachyolmia. We sequenced TRPV4 and identified 9 different mutations in 22 patients, 4 previously described, and 5 novel. There were 4 mutation-negative cases: one with MD and one with SMDK, both displaying atypical clinical and radiographic features for these diagnoses; and two with brachyolmia, who had isolated spine changes and no metaphyseal involvement. Conclusions Our data suggest the TRPV4 skeletal dysplasias represent a continuum of severity with areas of phenotypic overlap, even within the same family. We propose that AD brachyolmia lies at the mildest end of this spectrum and, since all cases described with this diagnosis and TRPV4 mutations display metaphyseal changes, we suggest that it is not a distinct entity but represents the mildest phenotypic expression of SMDK.

Abstract Background Prader-Willi syndrome (MIM #176270; PWS) is caused by lack of the paternally-derived copies, or their expression, of multiple genes in a 4 Mb region on chromosome 15q11.2. Known mechanisms include large deletions, maternal uniparental disomy or mutations involving the imprinting center. De novo balanced reciprocal translocations in 5 reported individuals had breakpoints clustering in SNRPN intron 2 or exon 20/intron 20. To further dissect the PWS phenotype and define the minimal critical region for PWS features, we have studied a 22 year old male with a milder PWS phenotype and a de novo translocation t(4;15)(q27;q11.2). Methods We used metaphase FISH to narrow the breakpoint region and molecular analyses to map the breakpoints on both chromosomes at the nucleotide level. The expression of genes on chromosome 15 on both sides of the breakpoint was determined by RT-PCR analyses. Results Pertinent clinical features include neonatal hypotonia with feeding difficulties, hypogonadism, short stature, late-onset obesity, learning difficulties, abnormal social behavior and marked tolerance to pain, as well as sticky saliva and narcolepsy. Relative macrocephaly and facial features are not typical for PWS. The translocation breakpoints were identified within SNRPN intron 17 and intron 10 of a spliced non-coding transcript in band 4q27. LINE and SINE sequences at the exchange points may have contributed to the translocation event. By RT-PCR of lymphoblasts and fibroblasts, we find that upstream SNURF/SNRPN exons and snoRNAs HBII-437 and HBII-13 are expressed, but the downstream snoRNAs PWCR1/HBII-85 and HBII-438A/B snoRNAs are not. Conclusion As part of the PWCR1/HBII-85 snoRNA cluster is highly conserved between human and mice, while no copy of HBII-438 has been found in mouse, we conclude that PWCR1/HBII-85 snoRNAs is likely to play a major role in the PWS- phenotype.

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder of unknown aetiology that affects numerous body systems including skin, brain and kidneys. Some TSC has been linked to chromosome 9, additional TSC genes on chromosomes 11 and 12 have been proposed, but the majority of TSC families remain unlinked. Using TSC families in which data had excluded linkage to chromosome 9, we failed to detect linkage with loci on chromosomes 11, 12 and others. One marker examined was D16S283, the closest locus on the proximal side of the polycystic kidney disease type 1 (PKD1) gene. Linkage between TSC and D16S283 demonstrated a lod score of 9.50 at theta = 0.02 with one family independently presenting a lod score of 4.44 at theta = 0.05. These data reveal an important TSC locus near the region of PKD1 on chromosome 16p13.

Background: The spinocerebellar ataxias (SCAs) are clinically and genetically heterogeneous. Currently, 27 forms are known, with the causative gene identified in 16. Although the majority of dominant pedigrees worldwide have SCAs 1, 2, 3, 6 or 8, new SCAs continue to be delineated. We describe a new disorder: SCA 30.Methods: An Australian family of Anglo-Celtic ethnicity manifested a relatively pure, slowly evolving ataxia. Six affected and four unaffected members were personally examined in a standardised fashion. MRI and nerve conduction studies were performed in two. An autosomal genome-wide linkage study was undertaken, and an in silico analysis of potential candidate genes in the linkage region was performed.Results: The six affected members had a relatively pure, slowly evolving ataxia developing in mid to late life, with only minor pyramidal signs and no evidence of neuropathy. All had hypermetric saccades with normal vestibulo-ocular reflex gain. Only one displayed (slight) gaze-evoked nystagmus. MRI showed cerebellar atrophy with preservation of nodulus/uvula and brainstem. Linkage analysis excluded currently known SCAs and identified a logarithm (base 10) of odds score of 3.0 at chromosome 4q34.3-q35.1, distinct from all previously reported loci. In silico prioritisation identified the gene ODZ3 as the most likely contender.Conclusions: SCA 30 is a previously undescribed cause of (relatively) pure adult-onset autosomal dominant cerebellar ataxia. The responsible gene is yet to be determined, but ODZ3 is a plausible candidate. [ABSTRACT FROM AUTHOR]

Background: Prader-Willi syndrome (MIM #176270; PWS) is caused by lack of the paternally-derived copies, or their expression, of multiple genes in a 4 Mb region on chromosome 15q11.2. Known mechanisms include large deletions, maternal uniparental disomy or mutations involving the imprinting center. De novo balanced reciprocal translocations in 5 reported individuals had breakpoints clustering in SNRPN intron 2 or exon 20/intron 20. To further dissect the PWS phenotype and define the minimal critical region for PWS features, we have studied a 22 year old male with a milder PWS phenotype and a de novo translocation t(4;15)(q27;q11.2). Methods: We used metaphase FISH to narrow the breakpoint region and molecular analyses to map the breakpoints on both chromosomes at the nucleotide level. The expression of genes on chromosome 15 on both sides of the breakpoint was determined by RT-PCR analyses. Results: Pertinent clinical features include neonatal hypotonia with feeding difficulties, hypogonadism, short stature, late-onset obesity, learning difficulties, abnormal social behavior and marked tolerance to pain, as well as sticky saliva and narcolepsy. Relative macrocephaly and facial features are not typical for PWS. The translocation breakpoints were identified within SNRPN intron 17 and intron 10 of a spliced non-coding transcript in band 4q27. LINE and SINE sequences at the exchange points may have contributed to the translocation event. By RT-PCR of lymphoblasts and fibroblasts, we find that upstream SNURF/SNRPN exons and snoRNAs HBII-437 and HBII-13 are expressed, but the downstream snoRNAs PWCR1/HBII-85 and HBII-438A/B snoRNAs are not. Conclusion: As part of the PWCR1/HBII-85 snoRNA cluster is highly conserved between human and mice, while no copy of HBII-438 has been found in mouse, we conclude that PWCR1/HBII-85 snoRNAs is likely to play a major role in the PWS- phenotype. [ABSTRACT FROM AUTHOR]

Transient neonatal diabetes (TND) is a rare type of diabetes that presents soon after birth, resolves by 18 months, and predisposes to diabetes later in life. A total of 30 patients were ascertained and investigated for aberrations of chromosome 6. A genotype/phenotype study was also performed. Genotypically, these patients can be classified into 4 etiologic groups. Group 1 had paternal uniparental isodisomy of chromosome 6 (11 cases, including 1 set of identical twins). Group 2 had a duplication involving chromosome band 6q24, which was paternal in origin where tested (4 sporadic cases and 7 familial cases from 2 families). Group 3 consisted of 1 patient with a loss of methylation at a CpG island within the TND critical region (1 sporadic case). Group 4 had no identifiable rearrangement of chromosome 6 (7 sporadic cases). Most patients were growth retarded at birth, presented at a median age of 3 days, and recovered at a median age of 12 weeks. In group 2, 2 relatives of the TND patients who presented with type 2 diabetes and no early history of TND had inherited an identical duplication. An abnormality of chromosome 6 was identified in approximately 70% of sporadic TND cases and in all familial cases. No significant clinical differences were found between the 4 etiological groups. The study has broadened the clinical spectrum of TND to include type 2 diabetes presenting in later life with no neonatal presentation. The findings are consistent with an imprinted gene for diabetes mapping to 6q24, which we predict will have an important function in normal pancreatic development. [ABSTRACT FROM AUTHOR]

A British Paediatric Association Surveillance Unit* study of neonatal diabetes determined a national incidence of 1 in 400,000 live births. Additional cases of transient neonatal diabetes were collected retrospectively. Most cases were of low birthweight at term: none had evidence of an autoimmune aetiopathogenesis. The median requirement for exogenous insulin treatment was three months. A significant number of cases developed type 2 diabetes in later life. Three of the 11 cases were found to have paternal uniparental isodisomy of chromosome 6. A further patient carried an unbalanced duplication of 6q 22-23, inherited from the father, which localised a potentially imprinted gene for diabetes to this region. The fact that low birthweight predisposes to type 2 diabetes in later life is well established, but a genetic defect that may relate both to intrauterine growth failure and the development of type 2 diabetes in later life has now been identified. [ABSTRACT FROM AUTHOR]

Place cells in the hippocampus and grid cells in the entorhinal cortex are elements of a neural map of self position 1-5 . For these cells to benefit navigation, their representation must be dynamically related to the surrounding locations 2 . A candidate mechanism for linking places along an animal's path has been described for place cells, in which the sequence of spikes in each cycle of the hippocampal theta oscillation encodes a trajectory from the animal's current location towards upcoming locations 6-8 . In mazes that bifurcate, such trajectories alternately traverse the two upcoming arms when the animal approaches the choice point 9,10 , raising the possibility that the trajectories express available forward paths encoded on previous trials 10 . However, to bridge the animal's path with the wider environment, beyond places previously or subsequently visited, an experience-independent spatial sampling mechanism might be required. Here we show in freely moving rats that in individual theta cycles, ensembles of grid cells and place cells encode a position signal that sweeps linearly outwards from the animal's location into the ambient environment, with sweep direction alternating stereotypically between left and right across successive theta cycles. These sweeps are accompanied by, and aligned with, a similarly alternating directional signal in a discrete population of parasubiculum cells that have putative connections to grid cells via conjunctive grid × direction cells. Sweeps extend into never-visited locations that are inaccessible to the animal. Sweeps persist during REM sleep. The sweep directions can be explained by an algorithm that maximizes the cumulative coverage of the surrounding manifold space. The sustained and unconditional expression of theta-patterned left-right-alternating sweeps in the entorhinal-hippocampal positioning system provides an efficient 'look around' mechanism for sampling locations beyond the travelled path., Competing Interests: Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Repetitive stress injuries to the rotator cuff, and particularly the supraspinatus tendon (SST), are highly prevalent and debilitating. These injuries typically occur through the application of cyclic load below the threshold necessary to cause acute tears, leading to accumulation of incremental damage that exceeds the body's ability to heal, resulting in decreased mechanical strength and increased risk of frank rupture at lower loads. Consistent progression of fatigue damage across multiple model systems suggests a generalized tendon response to overuse. This finding may allow for interventions before gross injury of the SST occurs. Further research into the human SST response to fatigue loading is necessary to characterize the fatigue life of the tendon, which will help determine the frequency, duration, and magnitude of load spectra the SST may experience before injury. Future studies may allow in vivo SST strain analysis during specific activities, generation of a human SST stress-cycle curve, and characterization of damage and repair related to repetitive tasks., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Overuse injuries of the rotator cuff, particularly of the supraspinatus tendon (SST), are highly prevalent and debilitating in work, sport, and daily activities. Despite the clinical significance of these injuries, there remains a large degree of uncertainty regarding the pathophysiology of injury, optimal methods of nonoperative and operative repair, and how to adequately assess tendon injury and healing. The tendon response to fatigue damage resulting from overuse is different from that of acute rupture and results in either an adaptive (healing) or a maladaptive (degenerative) response. Factors associated with the degenerative response include increasing age, smoking, hypercholesterolemia, biological sex (variable by tendon), diabetes mellitus, and excessive load post fatigue damage. After injury, the average healing rate of tendon is approximately 1% per day and may be significantly influenced by biologic sex (females have lower collagen synthesis rates) and excessive load after damage. Although magnetic resonance imaging (MRI) is considered the gold standard in assessing acute tears as well as tendinopathic change in the SST, ultrasonography has proven to be a valuable tool to measure tendinopathic change in real time. Ultrasonography can determine multiple mechanical and structural parameters of the SST that are altered in fatigue loading. Thus, ultrasonography may be utilized to understand how these parameters change in response to SST overuse, and may aid in determining the activity level that places the SST at greater risk of rupture., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

The representation of an animal's position in the medial entorhinal cortex (MEC) is distributed across several modules of grid cells, each characterized by a distinct spatial scale. The population activity within each module is tightly coordinated and preserved across environments and behavioral states. Little is known, however, about the coordination of activity patterns across modules. We analyzed the joint activity patterns of hundreds of grid cells simultaneously recorded in animals that were foraging either in the light, when sensory cues could stabilize the representation, or in darkness, when such stabilization was disrupted. We found that the states of different modules are tightly coordinated, even in darkness, when the internal representation of position within the MEC deviates substantially from the true position of the animal. These findings suggest that internal brain mechanisms dynamically coordinate the representation of position in different modules, ensuring that they jointly encode a coherent and smooth trajectory., Competing Interests: Declaration of interests E.I.M. is on the Advisory Board of Neuron. All other authors declare no competing interests., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

The medial entorhinal cortex is part of a neural system for mapping the position of an individual within a physical environment 1 . Grid cells, a key component of this system, fire in a characteristic hexagonal pattern of locations 2 , and are organized in modules 3 that collectively form a population code for the animal's allocentric position 1 . The invariance of the correlation structure of this population code across environments 4,5 and behavioural states 6,7 , independent of specific sensory inputs, has pointed to intrinsic, recurrently connected continuous attractor networks (CANs) as a possible substrate of the grid pattern 1,8-11 . However, whether grid cell networks show continuous attractor dynamics, and how they interface with inputs from the environment, has remained unclear owing to the small samples of cells obtained so far. Here, using simultaneous recordings from many hundreds of grid cells and subsequent topological data analysis, we show that the joint activity of grid cells from an individual module resides on a toroidal manifold, as expected in a two-dimensional CAN. Positions on the torus correspond to positions of the moving animal in the environment. Individual cells are preferentially active at singular positions on the torus. Their positions are maintained between environments and from wakefulness to sleep, as predicted by CAN models for grid cells but not by alternative feedforward models 12 . This demonstration of network dynamics on a toroidal manifold provides a population-level visualization of CAN dynamics in grid cells., (© 2022. The Author(s).)

CA1 and subiculum (SUB) connect the hippocampus to numerous output regions. Cells in both areas have place-specific firing fields, although they are more dispersed in SUB. Weak responses to head direction and running speed have been reported in both regions. However, how such information is encoded in CA1 and SUB and the resulting impact on downstream targets are poorly understood. Here, we estimate the tuning of simultaneously recorded CA1 and SUB cells to position, head direction, and speed. Individual neurons respond conjunctively to these covariates in both regions, but the degree of mixed representation is stronger in SUB, and more so during goal-directed spatial navigation than free foraging. Each navigational variable could be decoded with higher precision, from a similar number of neurons, in SUB than CA1. The findings point to a possible contribution of mixed-selective coding in SUB to efficient transmission of hippocampal representations to widespread brain regions., Competing Interests: Declarations of interests The authors declare no competing interests., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)

Measuring the dynamics of neural processing across time scales requires following the spiking of thousands of individual neurons over milliseconds and months. To address this need, we introduce the Neuropixels 2.0 probe together with newly designed analysis algorithms. The probe has more than 5000 sites and is miniaturized to facilitate chronic implants in small mammals and recording during unrestrained behavior. High-quality recordings over long time scales were reliably obtained in mice and rats in six laboratories. Improved site density and arrangement combined with newly created data processing methods enable automatic post hoc correction for brain movements, allowing recording from the same neurons for more than 2 months. These probes and algorithms enable stable recordings from thousands of sites during free behavior, even in small animals such as mice., (Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

The network of grid cells in the medial entorhinal cortex (MEC) forms a fixed reference frame for mapping physical space. The mechanistic origin of the grid representation is unknown, but continuous attractor network models explain multiple fundamental features of grid cell activity. An untested prediction of these models is that the grid cell network should exhibit an activity correlation structure that transcends behavioral states. By recording from MEC cell ensembles during navigation and sleep, we found that spatial phase offsets of grid cells predict arousal-state-independent spike rate correlations. Similarly, state-invariant correlations between conjunctive grid-head direction and pure head direction cells were predicted by their head direction tuning offsets during awake behavior. Grid cells were only weakly correlated across grid modules, and module scale relationships disintegrated during slow-wave sleep, suggesting that grid modules function as independent attractor networks. Collectively, our observations imply that network states in MEC are expressed universally across brain and behavior states.

Introduction: Profound pulpal anesthesia is difficult to achieve in mandibular molars with irreversible pulpitis (IP). However, there are no published randomized controlled clinical trials comparing the success of supplemental buccal infiltration (BI) in mandibular first versus second molars with IP. The purpose of this prospective, randomized, double-blind study was to compare the efficacy of 4% articaine with 2% lidocaine for supplemental BIs in mandibular first versus second molars with IP after a failed inferior alveolar nerve block (IANB). This study's sample was combined with data from a previous trial., Methods: One hundred ninety-nine emergency subjects diagnosed with IP of a mandibular molar were selected and received an IANB with 4% articaine. Subjects who failed to achieve profound pulpal anesthesia, determined by a positive response to cold or pain upon access, randomly received 4% articaine or 2% lidocaine as a supplemental BI. Endodontic access was begun 5 minutes after infiltration. Success was defined as less than mild pain during endodontic access and instrumentation on the Heft-Parker visual analog scale., Results: There was a 25% IANB success rate with 4% articaine. The success rate for articaine supplemental BI in first molars was 61% versus 63% for second molars (P > .05). The success of lidocaine in first molars was 66%, but for second molars it was 32% (P = .004)., Conclusions: The success rate for IANB with 4% articaine was 25%. Articaine and lidocaine had similar success rates for supplemental infiltration in first molars, whereas articaine was significantly more successful for second molars. However, because BI often did not provide profound pulpal anesthesia, additional techniques including intraosseous anesthesia may still be required., (Copyright © 2018 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Mutations in RAD51 have recently been linked to human Congenital Mirror Movements (CMM), a developmental disorder of the motor system. The only gene previously linked to CMM encodes the Netrin-1 receptor DCC, which is important for formation of corticospinal and callosal axon tracts. Thus, we hypothesised that Rad51 has a novel role in Netrin-1-mediated axon development. In mouse primary motor cortex neurons, Rad51 protein was redistributed distally down the axon in response to Netrin-1, further suggesting a functional link between the two. We next manipulated Rad51 expression, and assessed Netrin-1 responsiveness. Rad51 siRNA knockdown exaggerated Netrin-1-mediated neurite branching and filopodia formation. RAD51 overexpression inhibited these responses, whereas overexpression of the CMM-linked R250Q mutation, a predicted loss-of-function, had no effect. Thus, Rad51 appears to negatively regulate Netrin-1 signalling. Finally, we examined whether Rad51 might operate by modulating the expression of the Unc5 family, known negative regulators of Netrin-1-responsiveness. Unc5b and Unc5c transcripts were downregulated in response to Rad51 knockdown, and upregulated with RAD51 overexpression, but not R250Q. Thus, Rad51 negatively regulates Netrin-1 signalling, at least in part, by modulating the expression of Unc5s. Imbalance of positive and negative influences is likely to lead to aberrant motor system development resulting in CMMs.

Chromosome abnormalities may cast light on the nature of mechanisms whereby normal anatomy evolves, and abnormal anatomy arises. Correlating genotype to phenotype is an exercise in which the geneticist and the anatomist can collaborate. The increasing power of the new genetic methodologies is enabling an increasing precision in the delineation of chromosome imbalances, even to the nucleotide level; but the classical skills of careful observation and recording remain as crucial as they always have been. Clin. Anat. 29:540-546, 2016. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)

Autosomal recessive cerebellar ataxia encompasses a large and heterogeneous group of neurodegenerative disorders. We employed single nucleotide polymorphism (SNP) analysis and whole exome sequencing to investigate a consanguineous Maori pedigree segregating ataxia. We identified a novel mutation in exon 10 of the SACS gene: c.7962T>G p.(Tyr2654*), establishing the diagnosis of autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS). Our findings expand both the genetic and phenotypic spectrum of this rare disorder, and highlight the value of high-density SNP analysis and whole exome sequencing as powerful and cost-effective tools in the diagnosis of genetically heterogeneous disorders such as the hereditary ataxias.

Introduction: Profound pulpal anesthesia in mandibular molars with irreversible pulpitis (IP) is often difficult to obtain and often requires supplemental injections after an ineffective inferior alveolar nerve block (IANB). The purpose of this prospective, randomized, double-blind study was to compare the efficacy of 4% articaine with 2% lidocaine for supplemental buccal infiltrations (BIs) after an ineffective IANB in mandibular molars with IP. In addition, the use of articaine for IANB and intraosseous injections was investigated., Methods: One hundred emergency patients diagnosed with IP of a mandibular molar were selected and received an IANB with 4% articaine. All injections were 1.7 mL with 1:100,000 epinephrine. All patients reported profound lip numbness after IANB. Patients with ineffective IANB (positive pulpal response to cold or pain on access) randomly received 4% articaine or 2% lidocaine as a supplemental BI. Endodontic access was initiated 5 minutes after deposition of the infiltration solution. Success was defined as no pain or no more than mild pain during endodontic access and instrumentation as measured on a visual analogue scale., Results: Seventy-four patients failed to achieve pulpal anesthesia after IANB with 4% articaine, resulting in IANB success rate of 26%. Success rates for supplemental BIs were 62% for articaine and 37% for lidocaine (P < .05). This effect was most pronounced in second molars (P < .05)., Conclusions: Supplemental BI with articaine was significantly more effective than lidocaine. The IANB success rate of 4% articaine confirmed published data., (Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

The neurophysiology of non-rapid eye movement sleep is characterized by the occurrence of neural network oscillations with distinct origins and frequencies, which act in concert to support sleep-dependent information processing. Thalamocortical circuits generate slow (0.25-4 Hz) oscillations reflecting synchronized temporal windows of cortical activity, whereas concurrent waxing and waning spindle oscillations (8-15 Hz) act to facilitate cortical plasticity. Meanwhile, fast (140-200 Hz) and brief (< 200 ms) hippocampal ripple oscillations are associated with the reactivation of neural assemblies recruited during prior wakefulness. The extent of the forebrain areas engaged by these oscillations, and the variety of cellular and synaptic mechanisms involved, make them sensitive assays of distributed network function. Each of these three oscillations makes crucial contributions to the offline memory consolidation processes supported by non-rapid eye movement sleep. Slow, spindle and ripple oscillations are therefore potential surrogates of cognitive function and may be used as diagnostic measures in a range of brain diseases. We review the evidence for disrupted slow, spindle and ripple oscillations in schizophrenia, linking pathophysiological mechanisms to the functional impact of these neurophysiological changes and drawing links with the cognitive symptoms that accompany this condition. Finally, we discuss potential therapies that may normalize the coordinated activity of these three oscillations in order to restore healthy cognitive function., (© 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.)

The 8-15 Hz thalamocortical oscillations known as sleep spindles are a universal feature of mammalian non-REM sleep, during which they are presumed to shape activity-dependent plasticity in neocortical networks. The cortex is hypothesized to contribute to initiation and termination of spindles, but the mechanisms by which it implements these roles are unknown. We used dual-site local field potential and multiple single-unit recordings in the thalamic reticular nucleus (TRN) and medial prefrontal cortex (mPFC) of freely behaving rats at rest to investigate thalamocortical network dynamics during natural sleep spindles. During each spindle epoch, oscillatory activity in mPFC and TRN increased in frequency from onset to offset, accompanied by a consistent phase precession of TRN spike times relative to the cortical oscillation. In mPFC, the firing probability of putative pyramidal cells was highest at spindle initiation and termination times. We thus identified "early" and "late" cell subpopulations and found that they had distinct properties: early cells generally fired in synchrony with TRN spikes, whereas late cells fired in antiphase to TRN activity and also had higher firing rates than early cells. The accelerating and highly structured temporal pattern of thalamocortical network activity over the course of spindles therefore reflects the engagement of distinct subnetworks at specific times across spindle epochs. We propose that early cortical cells serve a synchronizing role in the initiation and propagation of spindle activity, whereas the subsequent recruitment of late cells actively antagonizes the thalamic spindle generator by providing asynchronous feedback.

Electron tomography is becoming an increasingly important tool in materials science for studying the three-dimensional morphologies and chemical compositions of nanostructures. The image quality obtained by many current algorithms is seriously affected by the problems of missing wedge artefacts and non-linear projection intensities due to diffraction effects. The former refers to the fact that data cannot be acquired over the full 180° tilt range; the latter implies that for some orientations, crystalline structures can show strong contrast changes. To overcome these problems we introduce and discuss several algorithms from the mathematical fields of geometric and discrete tomography. The algorithms incorporate geometric prior knowledge (mainly convexity and homogeneity), which also in principle considerably reduces the number of tilt angles required. Results are discussed for the reconstruction of an InAs nanowire., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Genetic testing at a distance is commonplace where members of a family with a segregating germline mutation are geographically separated. For the most part, this challenge is addressed through the intervention of health professionals in taking and/or processing blood samples for subsequent couriering of DNA to a referral laboratory. In some circumstances, however, the collecting of pivotal clinical material may involve direct patient involvement. We describe such a situation where noninvasive saliva samples were provided by members of a family manifesting Von Hippel-Lindau (VHL) disease. The analysis identified a novel mutation in the VHL gene that was used to exclude other family members as being at risk of VHL disease.

Molecular karyotyping using chromosome microarray analysis (CMA) detects more pathogenic chromosomal anomalies than classical karyotyping, making CMA likely to become a first tier test for prenatal diagnosis. Detecting copy number variants of uncertain clinical significance raises ethical considerations. We consider the risk of harm to a woman or her fetus following the detection of a copy number variant of uncertain significance, whether it is ethically justifiable to withhold any test result information from a woman, what constitutes an 'informed choice' when women are offered CMA in pregnancy and whether clinicians are morally responsible for 'unnecessary' termination of pregnancy. Although we are cognisant of the distress associated with uncertain prenatal results, we argue in favour of the autonomy of women and their right to information from genome-wide CMA in order to make informed choices about their pregnancies. We propose that information material to a woman's decision-making process, including uncertain information, should not be withheld, and that it would be paternalistic for clinicians to try to take responsibility for women's decisions to terminate pregnancies. Non-directive pre-test and post-test genetic counselling is central to the delivery of these ethical objectives., (© 2012 John Wiley & Sons, Ltd.)

Spinocerebellar ataxia type 20 (SCA20), first reported in 2004, is a slowly progressive dominantly inherited disorder so far reported in a single Anglo-Celtic family from Australia. It is characterized by dentate calcification from an early stage of the illness. Dysarthria without ataxia is the first symptom in the majority - an unusual feature amongst the SCAs. In addition to ataxia, examination often reveals spasmodic dysphonia and palatal tremor, but the syndrome is otherwise fairly pure. The responsible genetic abnormality has been tentatively identified as a 260-kb duplication in the pericentric region of chromosome 11, but confirmation will necessarily await description of further families., (2012 Elsevier B.V. All rights reserved.)

Spinocerebellar ataxia type 15 (SCA15), first described in 2001, is a slowly progressive, relatively pure dominantly inherited ataxia. Six pedigrees have been reported to date, in Anglo-Celtic and Japanese populations. Other than notably slow progression, its main distinguishing characteristic is tremor, often affecting the head, which is seen in about half of affecteds and which may be the presenting feature. Neuroradiology shows cerebellar atrophy, particularly affecting the anterior and dorsal vermis. SCA15 is due to various deletions of the inositol 1,4,5-triphosphate receptor 1 gene (ITPR1) on the distal short arm of chromosome 3. The potential of point mutations in ITPR1 to cause SCA15 is not yet confirmed. "SCA16" has now been shown to be due to an ITPR1 mutation, and has now been subsumed into SCA15., (2012 Elsevier B.V. All rights reserved.)

Pituitary adenomas are common in the general population. Although most of them are sporadic, some occur in a familial setting. In familial pituitary adenoma patients it is common that no germline defects are found after screening of aryl hydrocarbon receptor interacting protein (AIP) and other genes known to underlie the condition, suggesting the existence of yet unknown predisposition genes. Recently, the RET proto-oncogene was found to be a novel in vivo interaction partner of AIP in the pituitary gland. Here, we have screened patients from 16 AIP mutation negative (AIPmut-) pituitary adenoma families for RET germline mutations to assess whether RET could play a role in pituitary adenoma predisposition, similar to AIP. We found five novel germline RET changes: one in RET Exon 4 and the rest in noncoding regions of RET. Two changes, c.1560*G > A and -1285 G > A, were segregated in affected family members. We also analyzed the RET region with enhancer element locator (EEL) to identify RET regulatory elements, and to see whether the changes resided in these. None of the variants mapped to the regions predicted by EEL. Expression of RET was examined in ten AIPmut- and seven AIP mutation positive (AIPmut+) somatotropinomas by immunohistochemistry, with a trend showing reduced expression in the latter (P = 0.05). We conclude that the RET variants are presumably not related to pituitary adenoma predisposition, although reduced RET expression may play a role in AIP-related genesis of somatotropinomas.

Periventricular heterotopia (PH) is a brain malformation characterised by heterotopic nodules of neurons lining the walls of the cerebral ventricles. Mutations in FLNA account for 20-24% of instances but a majority have no identifiable genetic aetiology. Often the co-occurrence of PH with a chromosomal anomaly is used to infer a new locus for a Mendelian form of PH. This study reports four PH patients with three different microdeletion syndromes, each characterised by high-resolution genomic microarray. In three patients the deletions at 1p36 and 22q11 are conventional in size, whilst a fourth child had a deletion at 7q11.23 that was larger in extent than is typically seen in Williams syndrome. Although some instances of PH associated with chromosomal deletions could be attributed to the unmasking of a recessive allele or be indicative of more prevalent subclinical migrational anomalies, the rarity of PH in these three microdeletion syndromes and the description of other non-recurrent chromosomal defects do suggest that PH may be a manifestation of multiple different forms of chromosomal imbalance. In many, but possibly not all, instances the co-occurrence of PH with a chromosomal deletion is not necessarily indicative of uncharacterised underlying monogenic loci for this particular neuronal migrational anomaly.

The identification of trisomy mosaicism in the prenatal setting is often shrouded with uncertainty for the genetic counsellor, and more importantly for the parents. The outcomes for these pregnancies may well be normal, but abnormalities and even in utero death are possibilities depending on the chromosomal abnormality and the degree of mosaicism. Advice to parents following the diagnosis of trisomy 16 mosaicism at chorionic villus sampling, with confirmation at subsequent amniocentesis, and in the setting of apparently normal fetal ultrasonography, is necessarily cautious. Malformations are seen in the majority of infants born following a diagnosis of mosaic trisomy 16 at amniocentesis, and intrauterine growth retardation, with postnatal catch-up, is the rule. We report here a case with a normal outcome by age 2.5 years and in fact with above-average language ability, and in whom trisomy mosaicism was confirmed postnatally., (Copyright (c) 2010 S. Karger AG, Basel.)

Background: Spinocerebellar ataxia type 15 (SCA15) is a slowly progressive neurodegenerative disorder characterized by cerebellar ataxia. Mutation of the ITPR1 gene (inositol 1,4,5-triphosphate receptor, type 1) has been identified recently as the underlying cause, and in most cases the molecular defect is a multiexon deletion. To date, 5 different SCA15 families have been identified with ITPR1 gene deletion., Methods: We have designed a synthetic, dual-color multiplex ligation-dependent probe amplification (MLPA) assay that measures copy number with high precision in selected exons across the entire length of ITPR1 and the proximal region of the neighboring gene, SUMF1 (sulfatase modifying factor 1). We screened 189 idiopathic ataxic patients with this MLPA assay., Results: We identified ITPR1 deletion of exons 1-10 in the previously reported AUS1 family (4 members) and deletion of exons 1-38 in a new family (2 members). In addition to the multiexon deletions, apparent single-exon deletions identified in 2 other patients were subsequently shown to be due to single-nucleotide changes at the ligation sites., Conclusions: The frequency of ITPR1 deletions is 2.7% in known familial cases. This finding suggests that SCA15 is one of the "less common" SCAs. Although the deletions in the 5 families identified worldwide thus far have been of differing sizes, all share deletion of exons 1-10. This region may be important, both in terms of the underlying pathogenetic mechanism and as a pragmatic target for an accurate, robust, and cost-effective diagnostic analysis.

We introduce a new algorithm for reconstructing an unknown shape from a finite number of noisy measurements of its support function. The algorithm, based on a least squares procedure, is very easy to program in standard software such as Matlab, and it works for both 2D and 3D reconstructions (in fact, in principle, in any dimension). Reconstructions may be obtained without any pre- or post-processing steps and with no restriction on the sets of measurement directions except their number, a limitation dictated only by computing time. An algorithm due to Prince and Willsky was implemented earlier for 2D reconstructions, and we compare the performance of their algorithm and ours. But our algorithm is the first that works for 3D reconstructions with the freedom stated in the previous paragraph. Moreover, under mild conditions, theory guarantees that outputs of the new algorithm will converge to the input shape as the number of measurements increases. In addition we offer a linear program version of the new algorithm that is much faster and better, or at least comparable, in performance at low levels of noise and reasonably small numbers of measurements. Another modification of the algorithm, suitable for use in a "focus of attention" scheme, is also described.

Background: Microarray genome analysis is realising its promise for improving detection of genetic abnormalities in individuals with mental retardation and congenital abnormality. Copy number variations (CNVs) are now readily detectable using a variety of platforms and a major challenge is the distinction of pathogenic from ubiquitous, benign polymorphic CNVs. The aim of this study was to investigate replacement of time consuming, locus specific testing for specific microdeletion and microduplication syndromes with microarray analysis, which theoretically should detect all known syndromes with CNV aetiologies as well as new ones., Methods: Genome wide copy number analysis was performed on 117 patients using Affymetrix 250K microarrays., Results: 434 CNVs (195 losses and 239 gains) were found, including 18 pathogenic CNVs and 9 identified as "potentially pathogenic". Almost all pathogenic CNVs were larger than 500 kb, significantly larger than the median size of all CNVs detected. Segmental regions of loss of heterozygosity larger than 5 Mb were found in 5 patients., Conclusions: Genome microarray analysis has improved diagnostic success in this group of patients. Several examples of recently discovered "new syndromes" were found suggesting they are more common than previously suspected and collectively are likely to be a major cause of mental retardation. The findings have several implications for clinical practice. The study revealed the potential to make genetic diagnoses that were not evident in the clinical presentation, with implications for pretest counselling and the consent process. The importance of contributing novel CNVs to high quality databases for genotype-phenotype analysis and review of guidelines for selection of individuals for microarray analysis is emphasised.

Conditioned cue-induced relapse to drug seeking is a major challenge to the treatment of drug addiction. It has been proposed that D-cycloserine might be useful in the prevention of relapse by reducing the conditioned reinforcing properties of drug-associated stimuli through facilitation of extinction. Here we show that intrabasolateral amygdala infusions of D-cycloserine in fact potentiate the reconsolidation of stimulus-cocaine memories to increase cue-induced relapse to drug seeking in rats with an extensive drug self-administration history. This elevation of cocaine seeking was correlated with an increase in the expression of the reconsolidation-associated gene zif268.

Spinocerebellar ataxia type 20 (SCA20) has been linked to chromosome 11q12, but the underlying genetic defect has yet to be identified. We applied single-nucleotide polymorphism genotyping to detect structural alterations in the genomic DNA of patients with SCA20. We found a 260 kb duplication within the previously linked SCA20 region, which was confirmed by quantitative polymerase chain reaction and fiber fluorescence in situ hybridization, the latter also showing its direct orientation. The duplication spans 10 known and 2 unknown genes, and is present in all affected individuals in the single reported SCA20 pedigree. While the mechanism whereby this duplication may be pathogenic remains to be established, we speculate that the critical gene within the duplicated segment may be DAGLA, the product of which is normally present at the base of Purkinje cell dendritic spines and contributes to the modulation of parallel fiber-Purkinje cell synapses.