Interfacing with Neural Activity via Femtosecond Laser Stimulation of Drug-Encapsulating Liposomal Nanostructures

External control over rapid and precise release of chemicals in the brain potentially provides a powerful interface with neural activity. Optical manipulation techniques, such as optogenetics and caged compounds, enable remote control of neural activity and behavior with fine spatiotemporal resolution. However, these methods are limited to chemicals that are naturally present in the brain or chemically suitable for caging. Here, we demonstrate the ability to interface with neural functioning via a wide range of neurochemicals released by stimulating loaded liposomal nanostructures with femtosecond lasers. Using a commercial two-photon microscope, we released inhibitory or excitatory neurochemicals to evoke subthreshold and suprathreshold changes in membrane potential in a live mouse brain slice. The responses were repeatable and could be controlled by adjusting laser stimulation characteristics. We also demonstrate the release of a wider range of chemicals—which previously were impossible to release by optogenetics or uncaging—including synthetic analogs of naturally occurring neurochemicals. In particular, we demonstrate the release of a synthetic receptor-specific agonist that exerts physiological effects on long-term synaptic plasticity. Further, we show that the loaded liposomal nanostructures remain functional for weeks in a live mouse. In conclusion, we demonstrate new techniques capable of interfacing with live neurons, and extendable to in vivo applications

Identification of kinectin as a novel Behçet's disease autoantigen

There has been some evidence that Behçet's disease (BD) has a significant autoimmune component but the molecular identity of putative autoantigens has not been well characterized. In the initial analysis of the autoantibody profile in 39 Chinese BD patients, autoantibodies to cellular proteins were uncovered in 23% as determined by immunoblotting. We have now identified one of the major autoantibody specificities using expression cloning. Serum from a BD patient was used as a probe to immunoscreen a λZAP expression cDNA library. Candidate autoantigen cDNAs were characterized by direct nucleotide sequencing and their expressed products were examined for reactivity to the entire panel of BD sera using immunoprecipitation. Reactivity was also examined with normal control sera and disease control sera from patients with lupus and Sjögren's syndrome. Six independent candidate clones were isolated from the cDNA library screen and were identified as overlapping partial human kinectin cDNAs. The finding that kinectin was an autoantigen was verified in 9 out of 39 (23%) BD patient sera by immunoprecipitation of the in vitro translation products. Sera from controls showed no reactivity. The significance of kinectin as a participant in autoimmune pathogenesis in BD and the potential use of autoantibody to kinectin in serodiagnostics are discussed

Risk of adverse events following the initiation of antihypertensives in older people with complex health needs:a self-controlled case series in the United Kingdom

BACKGROUND: We assessed the risk of adverse events-severe acute kidney injury (AKI), falls and fractures-associated with use of antihypertensives in older patients with complex health needs (CHN). SETTING: UK primary care linked to inpatient and mortality records. METHODS: The source population comprised patients aged &gt;65, with ≥1 year of registration and unexposed to antihypertensives in the year before study start. We identified three cohorts of patients with CHN, namely, unplanned hospitalisations, frailty (electronic frailty index deficit count ≥3) and polypharmacy (prescription of ≥10 medicines). Patients in any of these cohorts were included in the CHN cohort. We conducted self-controlled case series for each cohort and outcome (AKI, falls, fractures). Incidence rate ratios (IRRs) were estimated by dividing event rates (i) during overall antihypertensive exposed patient-time over unexposed patient-time; and (ii) in the first 30 days after treatment initiation over unexposed patient-time. RESULTS:Among 42,483 patients in the CHN cohort, 7,240, 5,164 and 450 individuals had falls, fractures or AKI, respectively. We observed an increased risk for AKI associated with exposure to antihypertensives across all cohorts (CHN: IRR 2.36 [95% CI: 1.68-3.31]). In the 30 days post-antihypertensive treatment initiation, a 35-50% increased risk for falls was found across all cohorts and increased fracture risk in the frailty cohort (IRR 1.38 [1.03-1.84]). No increased risk for falls/fractures was associated with continuation of antihypertensive treatment or overall use. CONCLUSION: Treatment with antihypertensives in older patients was associated with increased risk of AKI and transiently elevated risk of falls in the 30 days after starting antihypertensive therapy.</p

Secure network coding with a cost criterion

Thesis (M. Eng. and S.B.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.Includes bibliographical references (p. 67-68).Network coding is a viable alterative to traditional routing methods that are being used in current data networks as it offers many advantages, including higher throughput rates and lower network costs. Although research has been conducted with regards to the cost and security issues of network coding, a joint investigation of these two parameters has not been done yet, thus providing the motivation for this thesis. For this thesis, we consider the situation where a set of messages is to be multicasted across the network, of which a known subset is of interest to a wiretapping adversary. The problem that we attempt to solve is to find a network coding scheme that has both a low network cost and a low probability of the wiretapper being able to retrieve all the messages of interest. We make use of random linear codes in anticipation for decentralized implementation of the scheme, and focus on the problem of finding the multicast subgraph. As an exact algorithmic solution is difficult, we propose two heuristic solutions, and compare their performances to traditional routing through a simulation study on Rocketfuel networks. Our results suggest that network coding can be more effective than routing for this low cost and secure data multicast problem, especially when the links are not easily tapped.by Jianlong Tan.M.Eng.and S.B

Derivation and comparison of formulae for the adjustment of total calcium

Background: Free ionized calcium (Ca2+) is the biologically active component of total calcium (TCa) and hence responsible for its biological action. TCa is routinely adjusted for albumin using several formulae (e.g. James, Orell, Payne and Berry) to more closely reflect Ca2+. Here, we derive a novel formula to estimate Ca2+ and compare its performance to established formulae. Methods: Cohort for prediction of Ca2+: 2806 serum samples (TCa) taken contemporaneously with blood gas samples (Ca2+) at Imperial College Healthcare NHS Trust were used to derive formulae to estimate Ca2+ using multivariable linear regression. Cohort for prediction of PTH: Performance of novel and existing formulae to predict PTH in 5510 patients was determined by Spearman correlation. Results: Ca2+ prediction Cohort: Adjusted calcium (r2 = 0.269) was less strongly associated with Ca2+, than TCa (r2 = 0.314). Prediction of Ca2+ from a newly derived formula incorporating TCa, potassium, albumin, and hematocrit had an improved r2 of 0.327, whereas inclusion of all available parameters increased the r2 further to 0.364. Of the established formulae, James performed best in predicting Ca2+ (r2 = 0.27). PTH prediction cohort: Berry resulted in higher whereas Orell in lower adjusted calcium levels. Prediction of PTH was strongest in the setting of hypercalcemia, with James having the highest Spearman correlation coefficient (+0.496) similar to including all parameters (+0.499). Conclusion: Adjustment of calcium for albumin using established formulae does not always outperform unadjusted TCa in the reflection of Ca2+. Further prospective studies are needed to optimise adjustment of TCa and to establish bounds for validity

Is there an association between early weight status and utility based health-related quality of life in young children?

Purpose Few studies focus on the health-related quality of life (HRQoL) of preschool children with overweight or obesity. This is relevant for evaluation of obesity prevention trials using a quality-adjusted life year (QALY) framework. This study examined the association between weight status in the preschool years and HRQoL at age 5 years, using a preference-based instrument. Methods HRQoL [based on parent proxy version of the Health Utilities Index Mark 3 (HUI3)] and weight status were measured in children born in Australia between 2007 and 2009. Children’s health status was scored across eight attributes of the HUI3—vision, hearing, speech, ambulation, dexterity, emotion, cognition and pain, and these were used to calculate a multi-attribute utility score. Ordinary least squares (OLS), Tobit and two-part regressions were used to model the association between weight status and multi-attribute utility. Results Of the 368 children for whom weight status and HUI3 data were available, around 40% had overweight/obesity. After adjusting for child’s sex, maternal education, marital status and household income, no significant association between weight status in the preschool years and multi-attribute utility scores at 5 years was found. Conclusions Alternative approaches for capturing the effects of weight status in the preschool years on preference-based HRQoL outcomes should be tested. The application of the QALY framework to economic evaluations of obesity-related interventions in young children should also consider longitudinal effects over the life-course

Mimicking subsecond neurotransmitter dynamics with femtosecond laser stimulated nanosystems

Existing nanoscale chemical delivery systems target diseased cells over long, sustained periods of time, typically through one-time, destructive triggering. Future directions lie in the development of fast and robust techniques capable of reproducing the pulsatile chemical activity of living organisms, thereby allowing us to mimic biofunctionality. Here, we demonstrate that by applying programmed femtosecond laser pulses to robust, nanoscale liposome structures containing dopamine, we achieve sub-second, controlled release of dopamine – a key neurotransmitter of the central nervous system – thereby replicating its release profile in the brain. The fast delivery system provides a powerful new interface with neural circuits and to the larger range of biological functions that operate on this short timescale