IFT80 mutations cause a novel complex ciliopathy phenotype with retinal degeneration

Ciliopathies, a growing pleotropic class of diseases due to mutations in genes that play an important role in primary cilia function. These highly conserved organelles are key to cell signaling. We now know, that mutations in one gene may lead to more than one ciliopathy phenotype and that one ciliopathy phenotype may be due to mutations in more than one gene. We studied the case of a female child with a novel ciliopathy phenotype and identified two novel mutations in the gene IFT80. Previously, mutations in IFT80 have been associated with a very narrow rib cage and failure of the lungs. Bone anomalies are also part of this IFT80-condition but with no vision problems documented. Our case had none of the features known to be associated with IFT80 mutations and had retinal degeneration (RD). This work broadens the IFT80-phenotype spectrum and also shows RD can be a feature of many ciliopathies.

Health promotion through sport: international sport federations’ priorities, actions and opportunities

Objective

To identify areas of priority and activity for international sportsfederations (IFs) with respect to athlete health and safety, and global health. Results serve to direct the work of the Association of Summer Olympic IF Medical and Scientific Consultative Group, the International Olympic Committee and to influence IFs’ planning and priorities.

Methods

The 28 IFs participating in the Summer Olympic Games (2016) were asked to rank the relative importance of 11 health-related topics and to report their activities or research initiatives on 27 identified topics using an electronic survey. A comparison with a similar survey (2012) was made.

Results

The response rate was 100%. In general, the ‘fight against doping’ had the highest priority followed by ‘image as a safe sport’. The topics with the lowest importance ratings were ‘increasing the number of elite athletes’, and ‘health of the general population’. Despite ranking ‘health of your athletes,’ as a top priority, IFs are not addressing all aspects of athlete health. In comparison with 2012, there was a significant decrease in priority for IFs is ‘health of the general population’.

Conclusion

Despite the widespread knowledge of the importance of the promotion of physical activity (sport) on global health, the decreasing priority and programming of the IFs on physical activity promotion is concerning. Although IFs have prioritised the protection of the health of elite athletes, there are gaps in programming demonstrating that IFs are missing important areas of athlete health. Improving recreational athlete health programming could also benefit population health as well as improve IF fan base and sport participation.

Improvements to sample processing and measurement to enable more widespread environmental application of tritium

Previous measurements have demonstrated the wealth of information that tritium (T) can provide on environmentally relevant processes. We present modifications to sample preparation approaches that enable T measurement by proportional counting on small sample sizes equivalent to 120mg of water and demonstrate the accuracy of these methods on a suite of standardized water samples. We identify a current quantification limit of 92.2 TU which, combined with our small sample sizes, correlates to as little as 0.00133Bq of total T activity. This enhanced method should provide the analytical flexibility needed to address persistent knowledge gaps in our understanding of both natural and artificial T behavior in the environment.

Mechanisms of Stain Formation on Teeth, in Particular Associated with Metal Ions and Antiseptics

Much has been written on the subject of extrinsic tooth discoloration, but, except when the pigment is intentionally applied, the etiologies and mechanisms are poorly understood. Extrinsic stains have been classified as non-metallic or metallic. The pigment usually lies not on or in the dental tissues, but in surface deposits, particularly the acquired pellicle layer and at sites receiving limited cleaning. Whether pigments absorb, adsorb, or chemically interact with dental surfaces is unclear. Some stains merely seem to reflect the color of the apparent source, whereas others have been ascribed to a secondary chemical alteration of a substance at the tooth or pellicle surface. Theories of chromogenic bacteria and formation of metal sulfides are frequently propounded but without clear supportive evidence. Staining by cationic antiseptics and, to a lesser extent, metal salts has attracted research interest. Chlorhexidine and other cationic antiseptics, it is hypothesized, may catalyze browning reactions or facilitate metal sulfide formation in pellicle. Controlled clinical studies have repeatedly shown that dental and mucosal staining associated with the use of chlorhexidine and some metal salts is dependent upon volunteers' imbibing reasonable quantities of chromogenic beverages, such as tea. However, it must be appreciated that cationic antiseptics and polyvalent metals can precipitate chromogenic material from a large range of dietary compounds. The control of dental staining, at least that associated with chlorhexidine, can be achieved both in vitro and in vivo by the use of oxidizing agents which appear to remove the stain physically from the surfaces.

Variation in Responses to Sprint Training in Male Youth Athletes: A Meta-analysis

The trainability of youths and the existence of periods of accelerated adaptation to training have become key subjects of debate in exercise science. The purpose of this meta-analysis was to characterise youth athletes' adaptability to sprint training across PRE-, MID-, and POST-peak height velocity (PHV) groups. Effect sizes were calculated as a measure of straight-line sprinting performance with studies qualifying based on the following criteria: (a) healthy male athletes who were engaged in organised sports; (b) groups of participants with a mean age between 10 and 18 years; (c) sprint training intervention duration between 4 and 16 weeks. Standardised mean differences showed sprint training to be moderately effective (Effect size=1.01, 95% confidence interval: 0.43-1.59) with adaptive responses being of large and moderate magnitude in the POST- (ES=1.39; 0.32-2.46) and MID- (ES=1.15; 0.40-1.9) PHV groups respectively. A negative effect size was found in the PRE group (ES=-0.18; -1.35-0.99). Youth training practitioners should prescribe sprint training modalities based on biological maturation status. Twice weekly training sessions should comprise up to 16 sprints of around 20 m with a work-to-rest ratio of 1:25 or greater than 90 s.

An implantable 64-channel neural interface with reconfigurable recording and stimulation

Next generation implantable medical devices will have the potential to provide more precise and effective therapies through adaptive closed-loop controllers that combine sensing and stimulation across larger numbers of electrode channels. A major challenge in the design of such devices is balancing increased functionality and channel counts with the miniaturization required for implantation within small anatomical spaces. Customized therapies will require adaptive systems capable of tuning which channels are sensed and stimulated to overcome variability in patient-specific needs, surgical placement of electrodes, and chronic physiological responses. In order to address these challenges, we have designed a miniaturized implantable fully-reconfigurable front-end system that is integrated into the distal end of an 8-wire lead, enabling up to 64 electrodes to be dynamically configured for sensing and stimulation. Full reconfigurability is enabled by two custom 32×2 cross-point switch (CPS) matrix ASICs which can route any electrode to either an amplifier with reprogrammable bandwidth and integrated ADC or to one of two independent stimulation channels that can be driven through the lead. The 8-wire circuit includes a digital interface for robust communication as well as a charge-balanced powering scheme for enhanced safety. The system is encased in a hermetic package designed to fit within a 14 mm bur-hole in the skull for neuromodulation of the brain, but could easily be adapted to enhance therapies across a broad spectrum of applications.

Neural signal processing and closed-loop control algorithm design for an implanted neural recording and stimulation system

A fully autonomous intracranial device is built to continually record neural activities in different parts of the brain, process these sampled signals, decode features that correlate to behaviors and neuropsychiatric states, and use these features to deliver brain stimulation in a closed-loop fashion. In this paper, we describe the sampling and stimulation aspects of such a device. We first describe the signal processing algorithms of two unsupervised spike sorting methods. Next, we describe the LFP time-frequency analysis and feature derivation from the two spike sorting methods. Spike sorting includes a novel approach to constructing a dictionary learning algorithm in a Compressed Sensing (CS) framework. We present a joint prediction scheme to determine the class of neural spikes in the dictionary learning framework; and, the second approach is a modified OSort algorithm which is implemented in a distributed system optimized for power efficiency. Furthermore, sorted spikes and time-frequency analysis of LFP signals can be used to generate derived features (including cross-frequency coupling, spike-field coupling). We then show how these derived features can be used in the design and development of novel decode and closed-loop control algorithms that are optimized to apply deep brain stimulation based on a patient's neuropsychiatric state. For the control algorithm, we define the state vector as representative of a patient's impulsivity, avoidance, inhibition, etc. Controller parameters are optimized to apply stimulation based on the state vector's current state as well as its historical values. The overall algorithm and software design for our implantable neural recording and stimulation system uses an innovative, adaptable, and reprogrammable architecture that enables advancement of the state-of-the-art in closed-loop neural control while also meeting the challenges of system power constraints and concurrent development with ongoing scientific research designed to define brain network connectivity and neural network dynamics that vary at the individual patient level and vary over time.

Predicting local field potentials with recurrent neural networks

We present a Recurrent Neural Network using LSTM (Long Short Term Memory) that is capable of modeling and predicting Local Field Potentials. We train and test the network on real data recorded from epilepsy patients. We construct networks that predict multi-channel LFPs for 1, 10, and 100 milliseconds forward in time. Our results show that prediction using LSTM outperforms regression when predicting 10 and 100 millisecond forward in time.

Packaging Architecture for an Implanted System that Monitors Brain Activity and Applies Therapeutic Stimulation

Deep brain stimulation therapies for Parkinson's disease utilize hardware that, from a packaging perspective, resembles those that are used in cardiac pacemakers. A hermetic package that contains stimulation electronics and a primary battery supply is implanted under the scalp into a recess formed in the skull. Stimulation probes, each with up to four electrodes, are inserted into the brain and connected to the electronics package via a plug and cable system. Unlike single-target devices such as cochlear implants and pacemakers, achieving this type of neuropsychiatric therapy requires the ability to record and stimulate in multiple and distributive areas of the brain, both cortical and subcortical. By contrast, the closed-loop neural stimulator being developed under the DARPA SUBNETS program utilizes probes, each of which carries up to 64 electrodes that can be switched between recording and stimulation functions. This capability necessitates locating low-noise amplifiers, switching and communication electronics in close proximity to each probe site. Each of these satellite electronics packages requires 10 electrical connections to the hub package, which significantly increases the complexity of the interconnect system relative to the current practice. The power requirements of this system preclude the use of a primary battery supply, so a large lithium ion battery is used, with a recharging coil and electronics. The hub system is composed of a connector header, electronics package, and battery pack that are fabricated separately and are interconnected by a flex circuit board, to allow it to conform to the skull for implanting. The standardized feedthrough substrate on the satellite, which can interface with multiple types of electrodes, along the system being reconfigurable, enables our architecture to support this new clinical research. It also allows the clinician to select satellite-electrode system based on a patient's needs, thus providing a customized, patient-specific therapeutic system. In this article, we have described the various packaging components of this system and the design considerations that drove our technology choices.

Package architecture and component design for an implanted neural stimulator with closed loop control

An implanted neural stimulator with closed loop control requires electrodes for stimulation pulses and recording neuron activity. Our system features arrays of 64 electrodes. Each electrode can be addressed through a cross bar switch, to enable it to be used for stimulation or recording. This electrode switch, a bank of low noise amplifiers with an integrated analog to digital converter, power conditioning electronics, and a communications and control gate array are co-located with the electrode array in a 14 millimeter diameter satellite package that is designed to be flush mounted in a skull burr hole. Our system features five satellite packages connected to a central hub processor-controller via ten conductor cables that terminate in a custom designed, miniaturized connector. The connector incorporates features of high reliability, military grade devices and utilizes three distinct seals to isolate the contacts from fluid permeation. The hub system is comprised of a connector header, hermetic electronics package, and rechargeable battery pack, which are mounted on and electrically interconnected by a flexible circuit board. The assembly is over molded with a compliant silicone rubber. The electronics package contains two antennas, a large coil, used for recharging the battery and a high bandwidth antenna that is used to download data and update software. The package is assembled from two machined alumina pieces, a flat base with brazed in, electrical feed through pins and a rectangular cover with rounded corners. Titanium seal rings are brazed onto these two pieces so that they can be sealed by laser welding. A third system antenna is incorporated in the flexible circuit board. It is used to communicate with an externally worn control package, which monitors the health of the system and allows both the user and clinician to control or modify various system function parameters.