266 research outputs found
Adult attentional functioning in families with children diagnosed as attention-deficit hyperactivity disorder
The purpose of this study was to explore what differences, if any, existed between individuals and families with or without children diagnosed as Attention-deficit Hyperactivity Disorder. Information was gathered to identify subjects according to such demographic and situational variables as age, race, education, occupation, income, and performance on tasks requiring sustained attention and concentration. to further understand possible etiology each subject completed a neuropsychological battery. Collected data was analyzed to determine if the differences were significant.;The subjects were selected from the author\u27s private practice and the local churches and schools that refer to that practice. Each subject completed a biographical questionnaire, the Gordon Diagnostic System (GDS) and the Luria-Nebraska Neuropsychological Battery, Form I, Adult version (LNNB). Chi-square analysis, t-tests, and difference of proportions tests were used to examine the collected data.;The groups were similar in terms of age. There were no statistically significant differences between groups on the LNNB. Several of the differences on the GDS measures of vigilance and distractibility did not achieve statistical significance.;Significant differences were noted on variables including education levels, response times during measures of sustained attention, concentration and distractibility, and historical behavioral checklists. A trend analysis of the findings was offered suggesting visual processing as contributing to the delays in response time. The performance of individuals demonstrating problems with attention, concentration, and distractibility revealed significant problems with writing and mathematics. Implications, conclusions, and suggestions for further research were offered
Systematics of the Rhinolophus Landeri Complex, with Evidence for 3 Additional Afrotropical Bat Species
Roughly a third of all horseshoe bat species (Rhinolophidae: Rhinolophus) are found in Africa, where a recent continent-wide genetic survey suggested the presence of both undescribed and apparently invalid species. Here, we focus on the R. landeri species complex and the recent elevation of R. lobatus Peters, 1852, to species rank. That action created ambiguity in the taxonomy of East African members of the group—are both R. landeri Martin, 1838, and R. lobatus sympatric in East Africa or is another, unnamed species present there? Here, we refine genetic, morphological, and behavioral characterizations of R. landeri and its erstwhile synonyms with samples from the vicinity of their type localities. The distribution of R. landeri appears to be limited to Central and West Africa; existing genetic records attributed to this species from Mali clearly represent another taxon. We marshal genetic evidence for the species-level distinction of R. dobsoni Thomas, 1904, from Sudan, which was previously considered a synonym of R. landeri. We reject R. axillaris J. A. Allen, 1917, as a synonym of the R. landeri complex, provisionally regarding it as a valid member of the landeri species group. Finally, we demonstrate that East Africa is home to a fourth species of the landeri complex that is named herein. Final resolution of the systematics of this species complex awaits expanded characterizations (especially of genetics, vocalizations, and noseleaves) and studies of variation in regions of contact
Inhibition of intestinal epithelial apoptosis improves survival in a murine model of radiation combined injury
World conditions place large populations at risk from ionizing radiation (IR) from detonation of dirty bombs or nuclear devices. In a subgroup of patients, ionizing radiation exposure would be followed by a secondary infection. The effects of radiation combined injury are potentially more lethal than either insult in isolation. The purpose of this study was to determine mechanisms of mortality and possible therapeutic targets in radiation combined injury. Mice were exposed to IR with 2.5 Gray (Gy) followed four days later by intratracheal methicillin-resistant Staphylococcus aureus (MRSA). While either IR or MRSA alone yielded 100% survival, animals with radiation combined injury had 53% survival (p = 0.01). Compared to IR or MRSA alone, mice with radiation combined injury had increased gut apoptosis, local and systemic bacterial burden, decreased splenic CD4 T cells, CD8 T cells, B cells, NK cells, and dendritic cells, and increased BAL and systemic IL-6 and G-CSF. In contrast, radiation combined injury did not alter lymphocyte apoptosis, pulmonary injury, or intestinal proliferation compared to IR or MRSA alone. In light of the synergistic increase in gut apoptosis following radiation combined injury, transgenic mice that overexpress Bcl-2 in their intestine and wild type mice were subjected to IR followed by MRSA. Bcl-2 mice had decreased gut apoptosis and improved survival compared to WT mice (92% vs. 42%; p<0.01). These data demonstrate that radiation combined injury results in significantly higher mortality than could be predicted based upon either IR or MRSA infection alone, and that preventing gut apoptosis may be a potential therapeutic target
Selective Inhibitors of the JMJD2 Histone Demethylases: Combined Nondenaturing Mass Spectrometric Screening and Crystallographic Approaches†
Ferrous ion and 2-oxoglutarate (2OG) oxygenases catalyze the demethylation of N(epsilon)-methylated lysine residues in histones. Here we report studies on the inhibition of the JMJD2 subfamily of histone demethylases, employing binding analyses by nondenaturing mass spectrometry (MS), dynamic combinatorial chemistry coupled to MS, turnover assays, and crystallography. The results of initial binding and inhibition assays directed the production and analysis of a set of N-oxalyl-d-tyrosine derivatives to explore the extent of a subpocket at the JMJD2 active site. Some of the inhibitors were shown to be selective for JMJD2 over the hypoxia-inducible factor prolyl hydroxylase PHD2. A crystal structure of JMJD2A in complex with one of the potent inhibitors was obtained; modeling other inhibitors based on this structure predicts interactions that enable improved inhibition for some compounds
Ribosomal oxygenases are structurally conserved from prokaryotes to humans
2-Oxoglutarate (2OG)-dependent oxygenases have important roles in the regulation of gene expression via demethylation of N-methylated chromatin components1,2 and in the hydroxylation of transcription factors3 and splicing factor proteins4. Recently, 2OG-dependent oxygenases that catalyse hydroxylation of transfer RNA5,6,7 and ribosomal proteins8 have been shown to be important in translation relating to cellular growth, TH17-cell differentiation and translational accuracy9,10,11,12. The finding that ribosomal oxygenases (ROXs) occur in organisms ranging from prokaryotes to humans8 raises questions as to their structural and evolutionary relationships. In Escherichia coli, YcfD catalyses arginine hydroxylation in the ribosomal protein L16; in humans, MYC-induced nuclear antigen (MINA53; also known as MINA) and nucleolar protein 66 (NO66) catalyse histidine hydroxylation in the ribosomal proteins RPL27A and RPL8, respectively. The functional assignments of ROXs open therapeutic possibilities via either ROX inhibition or targeting of differentially modified ribosomes. Despite differences in the residue and protein selectivities of prokaryotic and eukaryotic ROXs, comparison of the crystal structures of E. coli YcfD and Rhodothermus marinus YcfD with those of human MINA53 and NO66 reveals highly conserved folds and novel dimerization modes defining a new structural subfamily of 2OG-dependent oxygenases. ROX structures with and without their substrates support their functional assignments as hydroxylases but not demethylases, and reveal how the subfamily has evolved to catalyse the hydroxylation of different residue side chains of ribosomal proteins. Comparison of ROX crystal structures with those of other JmjC-domain-containing hydroxylases, including the hypoxia-inducible factor asparaginyl hydroxylase FIH and histone Nε-methyl lysine demethylases, identifies branch points in 2OG-dependent oxygenase evolution and distinguishes between JmjC-containing hydroxylases and demethylases catalysing modifications of translational and transcriptional machinery. The structures reveal that new protein hydroxylation activities can evolve by changing the coordination position from which the iron-bound substrate-oxidizing species reacts. This coordination flexibility has probably contributed to the evolution of the wide range of reactions catalysed by oxygenases
Cardiac troponins: from myocardial infarction to chronic disease.
Elucidation of the physiologically distinct subunits of troponin in 1973 greatly facilitated our understanding of cardiac contraction. Although troponins are expressed in both skeletal and cardiac muscle, there are isoforms of troponin I/T expressed selectively in the heart. By exploiting cardiac-restricted epitopes within these proteins, one of the most successful diagnostic tests to-date has been developed: cardiac troponin (cTn) assays. For the past decade, cTn has been regarded as the gold-standard marker for acute myocardial necrosis: the pathological hallmark of acute myocardial infarction (AMI). Whilst cTn is the cornerstone for ruling-out AMI in patients presenting with a suspected acute coronary syndrome (ACS), elevated cTn is frequently observed in those without clinical signs indicative of AMI, often reflecting myocardial injury of 'unknown origin'. cTn is commonly elevated in acute non-ACS conditions, as well as in chronic diseases. It is unclear why these elevations occur; yet they cannot be ignored as cTn levels in chronically unwell patients are directly correlated to prognosis. Paradoxically, improvements in assay sensitivity have meant more differential diagnoses have to be considered due to decreased specificity, since cTn is now more easily detected in these non-ACS conditions. It is important to be aware cTn is highly specific for myocardial injury, which could be attributable to a myriad of underlying causes, emphasising the notion that cTn is an organ-specific, not disease-specific biomarker. Furthermore, the ability to detect increased cTn using high-sensitivity assays following extreme exercise is disconcerting. It has been suggested troponin release can occur without cardiomyocyte necrosis, contradicting conventional dogma, emphasising a need to understand the mechanisms of such release. This review discusses basic troponin biology, the physiology behind its detection in serum, its use in the diagnosis of AMI, and some key concepts and experimental evidence as to why cTn can be elevated in chronic diseases
Modification of hERG1 channel gating by Cd2+
Each of the four subunits in a voltage-gated potassium channel has a voltage sensor domain (VSD) that is formed by four transmembrane helical segments (S1–S4). In response to changes in membrane potential, intramembrane displacement of basic residues in S4 produces a gating current. As S4 moves through the membrane, its basic residues also form sequential electrostatic interactions with acidic residues in immobile regions of the S2 and S3 segments. Transition metal cations interact with these same acidic residues and modify channel gating. In human ether-á-go-go–related gene type 1 (hERG1) channels, Cd2+ coordinated by D456 and D460 in S2 and D509 in S3 induces a positive shift in the voltage dependence of activation of ionic currents. Here, we characterize the effects of Cd2+ on hERG1 gating currents in Xenopus oocytes using the cut-open Vaseline gap technique. Cd2+ shifted the half-point (V1/2) for the voltage dependence of the OFF gating charge–voltage (QOFF-V) relationship with an EC50 of 171 µM; at 0.3 mM, V1/2 was shifted by +50 mV. Cd2+ also induced an as of yet unrecognized small outward current (ICd-out) upon repolarization in a concentration- and voltage-dependent manner. We propose that Cd2+ and Arg residues in the S4 segment compete for interaction with acidic residues in S2 and S3 segments, and that the initial inward movement of S4 associated with membrane repolarization displaces Cd2+ in an outward direction to produce ICd-out. Co2+, Zn2+, and La3+ at concentrations that caused ∼+35-mV shifts in the QOFF-V relationship did not induce a current similar to ICd-out, suggesting that the binding site for these cations or their competition with basic residues in S4 differs from Cd2+. New Markov models of hERG1 channels were developed that describe gating currents as a noncooperative two-phase process of the VSD and can account for changes in these currents caused by extracellular Cd2+
At the Crossroads of Sustainability: The Natural Recompositioning of Architecture
It is widely acknowledged that the mantra of sustainability has triggered a fundamental reversal in the core of design practice: If the original purpose of architecture was to protect humans from the destructive actions of nature,today it should protect nature from the damaging actions of humans. But sustainable design is far from being a coherent body of fully totalized ideas:it has a broad spectrum of disputing interpretations that oscillate between the
deterministic models of energy control and technological efficiencies, and the moralistic and romantic approaches that attempt to see in nature and natural processes a fundamental way to de-escalate the global urban footprint and its associated patterns of consumption.
However, mainstream green design has been evolving by progressively absorbing the narrative of deep ecology. Nature has been being integrated into architecture literally, by inserting vegetation onto buildings; digitally, by bringing environmental data into the design process (climate records, wind streams, sun rotation and air flows are computed, modelled and effectually shape architectures), and transcendentally, by claiming that sustainable architecture nurtures “the existing and evolving connections between spiritual and
material consciousness.” The acknowledgement of the inexorable affiliation between architecture and the environment is, of course, not exactly new. What
is distinctive today is the reification of the role of nature in architecture as an ideological stance, now totally intertwined with state-of-art data processing
and the market-driven tools brought by Natural Capitalism.
This paper will examine emblematic “green” buildings produced by leading architects such as Pelli Clarke Pelli, William McDonough, Stefano Boeri,
Norman Foster and BIG in the light of Tim Morton’s, Slavoj Zizek and Bruno Latour’s critique of nature. It will illustrate how, despite being able to successfully
forge new creative freedoms by exploring hybridizations between the domains of design and science, sustainability’s self-righteous “naturalistic” narrative is enabling a vision of the architect as an “expert manager”
focused on producing projects of ecologic “beautification” while assumed to be “saving the world,” effectively depoliticizing the architectural practice.
Nevertheless, these examples attest that there is a vast and fertile field of ideas to be explored and in this regard it is important to underline that we are still
in the embryonic outset of the engagement of architecture with sustainability
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