A role for astrocytes in cerebellar deficits in frataxin deficiency: Protection by insulin-like growth factor I

Inherited neurodegenerative diseases such as Friedreich's ataxia (FRDA), produced by deficiency of the mitochondrial chaperone frataxin (Fxn), shows specific neurological deficits involving different subset of neurons even though deficiency of Fxn is ubiquitous. Because astrocytes are involved in neurodegeneration, we analyzed whether they are also affected by frataxin deficiency and contribute to the disease. We also tested whether insulin-like growth factor I (IGF-I), that has proven effective in increasing frataxin levels both in neurons and in astrocytes, also exerts in vivo protective actions. Using the GFAP promoter expressed by multipotential stem cells during development and mostly by astrocytes in the adult, we ablated Fxn in a time-dependent manner in mice (FGKO mice) and found severe ataxia and early death when Fxn was eliminated during development, but not when deleted in the adult. Analysis of underlying mechanisms revealed that Fxn deficiency elicited growth and survival impairments in developing cerebellar astrocytes, whereas forebrain astrocytes grew normally. A similar time-dependent effect of frataxin deficiency in astrocytes was observed in a fly model. In addition, treatment of FGKO mice with IGF-I improved their motor performance, reduced cerebellar atrophy, and increased survival. These observations indicate that a greater vulnerability of developing cerebellar astrocytes to Fxn deficiency may contribute to cerebellar deficits in this inherited disease. Our data also confirm a therapeutic benefit of IGF-I in early FRDA deficiency.

Pathogen and Particle Associations in Wastewater: Significance and Implications for Treatment and Disinfection Processes

Disinfection guidelines exist for pathogen inactivation in potable water and recycled water, but wastewater with high numbers of particles can be more difficult to disinfect, making compliance with the guidelines problematic. Disinfection guidelines specify that drinking water with turbidity ≥1 Nephelometric Turbidity Units (NTU) is not suitable for disinfection and therefore not fit for purpose. Treated wastewater typically has higher concentrations of particles (1–10 NTU for secondary treated effluent). Two processes widely used for disinfecting wastewater are chlorination and ultraviolet radiation. In both cases, particles in wastewater can interfere with disinfection and can significantly increase treatment costs by increasing operational expenditure (chemical demand, power consumption) or infrastructure costs by requiring additional treatment processes to achieve the required levels of pathogen inactivation. Many microorganisms (viruses, bacteria, protozoans) associate with particles, which can allow them to survive disinfection processes and cause a health hazard. Improved understanding of this association will enable development of cost-effective treatment, which will become increasingly important as indirect and direct potable reuse of wastewater becomes more widespread in both developed and developing countries. This review provides an overview of wastewater and associated treatment processes, the pathogens in wastewater, the nature of particles in wastewater and how they interact with pathogens, and how particles can impact disinfection processes.

Cortical morphometry in frontoparietal and default mode networks in math-gifted adolescents

Math-gifted subjects are characterized by above-age performance in intelligence tests, exceptional creativity, and high task commitment. Neuroimaging studies reveal enhanced functional brain organization and white matter microstructure in the frontoparietal executive network of math-gifted individuals. However, the cortical morphometry of these subjects remains largely unknown. The main goal of this study was to compare the cortical morphometry of math-gifted adolescents with that of an age- and IQ-matched control group. We used surface-based methods to perform a vertex-wise analysis of cortical thickness and surface area. Our results show that math-gifted adolescents present a thinner cortex and a larger surface area in key regions of the frontoparietal and default mode networks, which are involved in executive processing and creative thinking, respectively. The combination of reduced cortical thickness and larger surface area suggests above-age neural maturation of these networks in math-gifted individuals. Hum Brain Mapp 37:1893-1902, 2016. © 2016 Wiley Periodicals, Inc.

Observation of a New Narrow Axial-Vector Meson a1(1420)

The COMPASS Collaboration at CERN has measured diffractive dissociation of 190  GeV/c pions into the π(-)π(-)π(+) final state using a stationary hydrogen target. A partial-wave analysis (PWA) was performed in bins of 3π mass and four-momentum transfer using the isobar model and the so far largest PWA model consisting of 88 waves. A narrow peak is observed in the f0(980)π channel with spin, parity and C-parity quantum numbers J(PC)=1(++). We present a resonance-model study of a subset of the spin-density matrix selecting 3π states with J(PC)=2(++) and 4(++) decaying into ρ(770)π and with J(PC)=1(++) decaying into f0(980)π. We identify a new a1 meson with mass (1414(-13)(+15))  MeV/c2 and width (153(-23)(+8))  MeV/c2. Within the final states investigated in our analysis, we observe the new a1(1420) decaying only into f0(980)π, suggesting its exotic nature.

Evaluation of a Smartphone-based audio-biofeedback system for improving balance in older adults--a pilot study

This study was designed to assess the effectiveness of a Smartphone-based audio-biofeedback (ABF) system for improving balance in older adults. This so-called "iBalance-ABF" system that we recetly developed is "all-inclusive" in the sense that its three main components of a balance prosthesis, (i) the sensory input unit, (ii) the processing unit, and (iii) the sensory output unit, are entirely embedded into the Smartphone. The underlying principle of this system is to supply the user with supplementary information about the medial-lateral (ML) trunk tilt relative to a predetermined adjustable "dead zone" through sound generation in earphones. Six healthy older adults voluntarily participated in this pilot study. Eyes closed, they were asked to stand upright and to sway as little as possible in two (parallel and tandem) stance conditions executed without and with the use of the iBalance-ABF system. Results showed that, without any visual information, the use of the Smartphone-based ABF allowed the older healthy adults to significantly decrease their ML trunk sway in the tandem stance posture and to mitigate the destabilizing effect induced by this particular stance. Although an extended study including a larger number of participants is needed to confirm these data, the present results are encouraging. They do suggest that Smartphone-based ABF system could be used for balance training and rehabilitation therapy in older adults.

Measurement of the charged-pion polarizability

The COMPASS collaboration at CERN has investigated pion Compton scattering, π(-)γ→π(-)γ, at center-of-mass energy below 3.5 pion masses. The process is embedded in the reaction π(-)Ni→π(-)γNi, which is initiated by 190 GeV pions impinging on a nickel target. The exchange of quasireal photons is selected by isolating the sharp Coulomb peak observed at smallest momentum transfers, Q(2)<0.0015  (GeV/c)(2). From a sample of 63,000 events, the pion electric polarizability is determined to be α(π)=(2.0±0.6(stat)±0.7(syst))×10(-4)  fm(3) under the assumption α(π)=-β(π), which relates the electric and magnetic dipole polarizabilities. It is the most precise measurement of this fundamental low-energy parameter of strong interaction that has been addressed since long by various methods with conflicting outcomes. While this result is in tension with previous dedicated measurements, it is found in agreement with the expectation from chiral perturbation theory. An additional measurement replacing pions by muons, for which the cross-section behavior is unambiguously known, was performed for an independent estimate of the systematic uncertainty.

Feedback interaction of research, advocacy, and clinical care applied to ALS research in South America

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease causing motor neuron loss and weakness. Worldwide prevalence is 4-6/100,000. Incidence is 1.5-2.7/100,000 per year and may be increasing. Studies suggest race and ethnicity affect the prevalence and incidence of ALS.(1) Understanding the impact of these variables on disease incidence could provide important insight into ALS determinants. A major roadblock for comparison across populations is the lack of epidemiologic data about ALS from many underdeveloped regions. In these regions, ALS is often undertreated due to health care disparities. This article discusses challenges for ALS research in South America (SA) and examines the ALS scientific record to explore the interactions and synergies of research, clinical care, and patient advocacy in underdeveloped regions.

Wegoto: A Smartphone-based approach to assess and improve accessibility for wheelchair users

This paper proposes a description of a Smartphone-based approach to assess and improve accessibility for wheelchair users. The developed system employs a dedicated Smartphone application that records various complementary sensor measurements (acceleration, deceleration, inclination, orientation, speed, GPS position) and permits obstacle denunciation. Then, accessibility information are reported on maps in a Geographic Information System which can calculate the most accessible route for wheelchair users taking into account their profiles and capabilities. A case study involving a wheelchair-dependent paraplegic was performed to preliminary assess the feasibility of our Smartphone-based approach to provide an accessibility index for wheelchair users. Although preliminary, our results do suggest that the Wegoto system could be used as an innovative assistive navigation system for wheelchair users and ultimately could help to improve their autonomy and quality of life.

White matter microstructure correlates of mathematical giftedness and intelligence quotient

Recent functional neuroimaging studies have shown differences in brain activation between mathematically gifted adolescents and controls. The aim of this study was to investigate the relationship between mathematical giftedness, intelligent quotient (IQ), and the microstructure of white matter tracts in a sample composed of math-gifted adolescents and aged-matched controls. Math-gifted subjects were selected through a national program based on detecting enhanced visuospatial abilities and creative thinking. We used diffusion tensor imaging to assess white matter microstructure in neuroanatomical connectivity. The processing included voxel-wise and region of interest-based analyses of the fractional anisotropy (FA), a parameter which is purportedly related to white matter microstructure. In a whole-sample analysis, IQ showed a significant positive correlation with FA, mainly in the corpus callosum, supporting the idea that efficient information transfer between hemispheres is crucial for higher intellectual capabilities. In addition, math-gifted adolescents showed increased FA (adjusted for IQ) in white matter tracts connecting frontal lobes with basal ganglia and parietal regions. The enhanced anatomical connectivity observed in the forceps minor and splenium may underlie the greater fluid reasoning, visuospatial working memory, and creative capabilities of these children.

Biomarkers of exposure to metal dust in exhaled breath condensate: methodology optimization

In occupational assessments where workers are exposed to metal dust, the liquid condensate of exhaled breath (EBC) may provide unique indication of pulmonary exposure. The main goal of this study was to demonstrate the quality of EBC to biological monitoring of human exposure. A pilot study was performed in a group of metal dust-exposed workers and a group of nonexposed individuals working in offices. Only metal dust-exposed workers were followed along the working week to determine the best time of collection. Metal analyses were performed with inductively coupled plasma mass spectrometry (ICP-MS). Analytical methodology was tested using an EBC sample pool for several occupationally exposed metals: potassium, chromium, manganese, copper, zinc, strontium, cadmium, antimony, and lead. Metal contents in EBC of exposed workers were higher than controls at the beginning of the shift and remained augmented throughout the working week. The results obtained support the establishment of EBC as an indicator of pulmonary exposure to metals.

Frataxin deficiency unveils cell-context dependent actions of insulin-like growth factor I on neurons

BACKGROUND

Friedreich's ataxia (FRDA) is a neurodegenerative disease caused by deficiency of the mitochondrial iron chaperone frataxin (Fxn). FRDA has no cure, but disease-modifying strategies to increase frataxin are under study. Because insulin-like growth factor I (IGF-I) has therapeutic effects in various types of cerebellar ataxia and exerts protective actions on mitochondrial function, we explored the potential Fxn-stimulating activity of this growth factor on brain cells.

RESULTS

IGF-I normalized frataxin levels in frataxin-deficient neurons and astrocytes through its canonical Akt/mTOR signaling pathway. IGF-I also stimulated frataxin in normal astrocytes but not in normal neurons, whereas IGF-I stimulated the Akt/mTOR pathway in both types of cells. This cell context-dependent action of IGF-I on neurons suggested that the intrinsic regulation of Fxn in neurons is different than in astrocytes. Indeed, neurons express much higher levels of frataxin and are much more sensitive to Fxn deficiency than astrocytes; i.e.: only neurons die in the absence of frataxin. In addition, the half-life of frataxin is shorter in neurons than in astrocytes, while after blockade of the proteasome only neurons responded to IGF-I with an increase in frataxin levels. We also explore a potential therapeutic utility of IGF-I in FRDA-like transgenic mice (YG8R mice) and found that treatment with IGF-I normalized motor coordination in these moderately ataxic mice.

CONCLUSION

Exposure to IGF-I unveiled a cell-specific regulation of frataxin in neurons as compared to astrocytes. Collectively, these results indicate that IGF-I exerts cell-context neuroprotection in frataxin deficiency that maybe therapeutically effective.