Bioethics and the Brain

Microelectronics and medical imaging are bringing us closer to a world where mind reading is possible and blindness banished - but we may not want to live there. New ways of imaging the human brain and new developments in microelectronics are providing unprecedented capabilities for monitoring the brain in real time and even for controlling brain function. The technologies are novel, but some of the questions that they will raise are not. Electrical activity in the brain can reveal the contents of a person\u27s memory. New imaging techniques might allow physician to detect devastating diseases long before those diseases become clinically apparent. And researchers may one day find brain activity that correlates with behavior patterns such as tendencies toward alcoholism, aggression, pedophilia, or racism. But how reliable will the information be, how should it be used, and what will it do to our notion of privacy? Meanwhile, microelectronics is making access to the brain a two-way street. The same electrical stimulation technologies that allow some deaf people to hear could be fashioned to control behavior as well. What are the appropriate limits to the use of this technology? Ethicists are only now beginning to take note of these developments in neuroscience

Search for B0s oscillations using inclusive lepton events

A search for B0s oscillations is performed using a sample of semileptonic b-hadron decays collected by the ALEPH experiment during 1991-1995. Compared to previous inclusive lepton analyses, the proper time resolution and b-flavour mistag rate are significantly improved. Additional sensitivity to B0s mixing is obtained by identifying subsamples of events having a B0s purity which is higher than the average for the whole data sample. Unbinned maximum likelihood amplitude fits are performed to derive a lower limit of Deltam_s>9.5ps^-1 at 95% CL. Combining with the ALEPH D-s based analyses yields Deltam_s>9.6ps^-1 at 95% CL.Comment: 23 pages, 10 figure

The relationship between active travel to school and health-related fitness in children and adolescents: a systematic review

Background: Active travel to school (ATS) has been identified as an important source of physical activity for youth. However, the relationship between ATS and health-related fitness (HRF) among youth remains unclear. Methods: A systematic search of seven electronic databases (EMBASE, OVID MEDLINE, PsycINFO, PubMed, Scopus, SPORTDiscus and TRIS on line) was conducted in December 2009 and studies published since 1980 were considered for inclusion. Results: Twenty seven articles were identified that explored the relationship between ATS and the following aspects of HRF: weight status/body composition, cardiorespiratory fitness, muscular fitness and flexibility. Forty-eight percent of the studies that examined the relationship between ATS and weight status/body composition reported significant associations, this increased to 55% once poor quality studies were removed. Furthermore, the findings from five studies, including one longitudinal study, indicate that ATS is positively associated with cardiorespiratory fitness in youth. However, the evidence for the relationships between ATS and muscular fitness or flexibility is equivocal and limited by low study numbers. Conclusions: There is some evidence to suggest that ATS is associated with a healthier body composition and level of cardiorespiratory fitness among youth. Strategies to increase ATS are warranted and should be included in whole-of-school approaches to the promotion of physical activity

Insensitivity of alkenone carbon isotopes to atmospheric CO₂ at low to moderate CO₂ levels

Atmospheric pCO2 is a critical component of the global carbon system and is considered to be the major control of Earth’s past, present and future climate. Accurate and precise reconstructions of its concentration through geological time are, therefore, crucial to our understanding of the Earth system. Ice core records document pCO2 for the past 800 kyrs, but at no point during this interval were CO2 levels higher than today. Interpretation of older pCO2 has been hampered by discrepancies during some time intervals between two of the main ocean-based proxy methods used to reconstruct pCO2: the carbon isotope fractionation that occurs during photosynthesis as recorded by haptophyte biomarkers (alkenones) and the boron isotope composition (δ11B) of foraminifer shells. Here we present alkenone and δ11B-based pCO2 reconstructions generated from the same samples from the Plio-Pleistocene at ODP Site 999 across a glacial-interglacial cycle. We find a muted response to pCO2 in the alkenone record compared to contemporaneous ice core and δ11B records, suggesting caution in the interpretation of alkenone-based records at low pCO2 levels. This is possibly caused by the physiology of CO2 uptake in the haptophytes. Our new understanding resolves some of the inconsistencies between the proxies and highlights that caution may be required when interpreting alkenone-based reconstructions of pCO2

The First Structure of an RNA m5C Methyltransferase, Fmu, Provides Insight into Catalytic Mechanism and Specific Binding of RNA Substrate

AbstractThe crystal structure of E. coli Fmu, determined at 1.65 Å resolution for the apoenzyme and 2.1 Å resolution in complex with AdoMet, is the first representative of the 5-methylcytosine RNA methyltransferase family that includes the human nucleolar proliferation-associated protein p120. Fmu contains three subdomains which share structural homology to DNA m5C methyltransferases and two RNA binding protein families. In the binary complex, the AdoMet cofactor is positioned within the active site near a novel arrangement of two conserved cysteines that function in cytosine methylation. The site is surrounded by a positively charged cleft large enough to bind its unique target stem loop within 16S rRNA. Docking of this stem loop RNA into the structure followed by molecular mechanics shows that the Fmu structure is consistent with binding to the folded RNA substrate

Group 2 Innate Lymphoid Cells Are Redundant in Experimental Renal Ischemia-Reperfusion Injury.

Acute kidney injury (AKI) can be fatal and is a well-defined risk factor for the development of chronic kidney disease. Group 2 innate lymphoid cells (ILC2s) are innate producers of type-2 cytokines and are critical regulators of homeostasis in peripheral organs. However, our knowledge of their function in the kidney is relatively limited. Recent evidence suggests that increasing ILC2 numbers by systemic administration of recombinant interleukin (IL)-25 or IL-33 protects against renal injury. Whilst ILC2s can be induced to protect against ischemic- or chemical-induced AKI, the impact of ILC2 deficiency or depletion on the severity of renal injury is unknown. Firstly, the phenotype and location of ILC2s in the kidney was assessed under homeostatic conditions. Kidney ILC2s constitutively expressed high levels of IL-5 and were located in close proximity to the renal vasculature. To test the functional role of ILC2s in the kidney, an experimental model of renal ischemia-reperfusion injury (IRI) was used and the severity of injury was assessed in wild-type, ILC2-reduced, ILC2-deficient, and ILC2-depleted mice. Surprisingly, there were no differences in histopathology, collagen deposition or mRNA expression of injury-associated (Lcn2), inflammatory (Cxcl1, Cxcl2, and Tnf) or extracellular matrix (Col1a1, Fn1) factors following IRI in the absence of ILC2s. These data suggest the absence of ILC2s does not alter the severity of renal injury, suggesting possible redundancy. Therefore, other mechanisms of type 2-mediated immune cell activation likely compensate in the absence of ILC2s. Hence, a loss of ILC2s is unlikely to increase susceptibility to, or severity of AKI

Towards modifying the genetic predisposition for glaucoma: An overview of the contribution and interaction of genetic and environmental factors

Glaucoma, the leading cause of irreversible blindness worldwide, is a complex human disease, with both genetic and environmental determinants. The availability of large-scale, population-based cohorts and biobanks, combining genotyping and detailed phenotyping, has greatly accelerated research into the aetiology of glaucoma in recent years. Hypothesis-free genome-wide association studies have furthered our understanding of the complex genetic architecture underpinning the disease, while epidemiological studies have provided advances in the identification and characterisation of environmental risk factors. It is increasingly recognised that the combined effects of genetic and environmental factors may confer a disease risk that reflects a departure from the simple additive effect of the two. These gene-environment interactions have been implicated in a host of complex human diseases, including glaucoma, and have several important diagnostic and therapeutic implications for future clinical practice. Importantly, the ability to modify the risk associated with a particular genetic makeup promises to lead to personalised recommendations for glaucoma prevention, as well as novel treatment approaches in years to come. Here we provide an overview of genetic and environmental risk factors for glaucoma, as well as reviewing the evidence and discussing the implications of gene-environment interactions for the disease

Development of reverse-transcription PCR techniques to analyse the density and sex ratio of gametocytes in genetically diverse Plasmodium chabaudi infections

We have developed cross-genotype and genotype-specific quantitative reverse-transcription PCR (qRT-PCR) assays to detect and quantify the number of parasites, transmission stages (gametocytes) and male gametocytes in blood stage Plasmodium chabaudi infections. Our cross-genotype assays are reliable, repeatable and generate counts that correlate strongly (R(2)s > 90%) with counts expected from blood smears. Our genotype-specific assays can distinguish and quantify different stages of genetically distinct parasite clones (genotypes) in mixed infections and are as sensitive as our cross-genotype assays. Using these assays we show that gametocyte density and gametocyte sex ratios vary during infections for two genetically distinct parasite lines (genotypes) and present the first data to reveal how sex ratio is affected when each genotype experiences competition in mixed-genotype infections. Successful infection of mosquito vectors depends on both gametocyte density and their sex ratio and we discuss the implications of competition in genetically diverse infections for transmission success

Theory of ac electrokinetic behavior of spheroidal cell suspensions with an intrinsic dispersion

The dielectric dispersion, dielectrophoretic (DEP) and electrorotational (ER) spectra of spheroidal biological cell suspensions with an intrinsic dispersion in the constituent dielectric constants are investigated. By means of the spectral representation method, we express analytically the characteristic frequencies and dispersion strengths both for the effective dielectric constant and the Clausius-Mossotti factor (CMF). We identify four and six characteristic frequencies for the effective dielectric spectra and CMF respectively, all of them being dependent on the depolarization factor (or the cell shape). The analytical results allow us to examine the effects of the cell shape, the dispersion strength and the intrinsic frequency on the dielectric dispersion, DEP and ER spectra. Furthermore, we include the local-field effects due to the mutual interactions between cells in a dense suspension, and study the dependence of co-field or anti-field dispersion peaks on the volume fractions.Comment: accepted by Phys. Rev.