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Sample records for accelerated cerebral white

  1. Cerebral circulation during acceleration stress

    NASA Astrophysics Data System (ADS)

    Cirovic, Srdjan

    A mathematical model of the cerebrovascular system has been developed to examine the influence of acceleration on cerebral circulation. The objective is to distinguish the main factors that limit cerebral blood flow in pilots subjected to accelerations which exceed the gravitational acceleration of the earth (Gz > 1). The cerebrovascular system was approximated by an open-loop network of elastic tubes and the flow in blood vessels was modeled according to a one-dimensional theory of flow in collapsible tubes. Since linear analysis showed that the speed of pulse propagation in the intracranial vessels should not be modified by the skull constraint, the same governing equations were used for the intracranial vessels as for the rest of the network. The steady and pulsatile components of the cerebrospinal fluid pressure were determined from the condition that the cranial volume must be conserved. After the qualitative aspects of the model results were verified experimentally, the open-loop geometry was incorporated into a global mathematical model of the cardiovascular system. Both the mathematical models and the experiment show that cerebral blood flow diminishes for Gz > 1 due to an increase in the resistance of the large veins in the neck, which collapse as soon as the venous pressure becomes negative. In contrast, the conservation of the cranial volume requires that the cerebrospinal and venous pressure always be approximately the same, and the vessels contained in the cranial cavity do not collapse. Positive pressure breathing provides protection by elevating blood arterial and venous pressures at the heart, thus preventing the venous collapse and maintaining the normal cerebral vascular resistance.

  2. Microvasculature of the human cerebral white matter: arteries of the deep white matter.

    PubMed

    Nonaka, Hiroko; Akima, Michio; Hatori, Tsutomu; Nagayama, Tadashi; Zhang, Zean; Ihara, Fumie

    2003-06-01

    The vascular architecture of the human cerebral deep white matter was studied using soft X-ray and diaphanized specimens, achieved by intra-arterial injection of barium and vascular stain respectively, and also by electron microscopic examination of the corrosion cast of arteries in normal adult brains. The deep white matter arteries passed through the cerebral cortex with a few branches to the cortex and ran straight through the white matter. The arteries concentrated ventriculopetally to the white matter around the lateral ventricle. Anastomoses were noted around the ventricular wall at the terminals of the deep white matter arteries. No centrifugal branches irrigating the periventricular white matter from the lenticulo-striate arteries were observed in the present study. The presence of anastomoses among the terminal branches of deep white matter arteries protects against ischemic change or infarction in this area from an occlusion of a single deep white matter artery. This may lead to development of terminal zone infarction from ischemia or vascular diseases, affecting multiple deep white matter arteries. The subcortical and deep white matter arteries had thick adventitial sheaths and large adventitial spaces in the white matter but not in the cortex. The presence or absence of the adventitial space is regarded as another characteristic difference between the arteries in the white matter and cortex. This difference may influence pathological changes in vascular lesions in these respective areas.

  3. Radioactive microsphere study of cerebral blood flow under acceleration. Technical report

    SciTech Connect

    Greenlees, K.J.; Yoder, J.E.; Toth, D.M.; Oloff, C.M.; Karl, A.

    1980-11-01

    A study using radioactive microspheres for the investigation of cerebral blood flow during acceleration is described. Details of a technique for the blunt dissection of cerebral tissues are included. Results of flow studies at 3 and 5 G sub z acceleration stress indicate there is no selective regional preservation of cerebral tissue. (Author)

  4. Epigenetic Age Acceleration Assessed With Human White-Matter Images.

    PubMed

    Hodgson, Karen; Carless, Melanie A; Kulkarni, Hemant; Curran, Joanne E; Sprooten, Emma; Knowles, Emma E; Mathias, Samuel; Göring, Harald Hh; Yao, Nailin; Olvera, Rene L; Fox, Peter T; Almasy, Laura; Duggirala, Ravi; Blangero, John; Glahn, David C

    2017-04-06

    The accurate estimation of age using methylation data has proved a useful and heritable biomarker, with acceleration in epigenetic age predicting a number of age-related phenotypes. Measures of white matter integrity in the brain are also heritable and highly sensitive to both normal and pathological aging processes across adulthood. We consider the phenotypic and genetic interrelationships between epigenetic age acceleration and white matter integrity in humans. Our goal was to investigate processes that underlie inter-individual variability in age-related changes in the brain. Using blood taken from a Mexican-American extended pedigree sample (n=628; age=23.28-93.11 years), epigenetic age was estimated using the method developed by S. Horvath (2013). For n=376 individuals, DTI scans were also available. The interrelationship between epigenetic age acceleration and global white matter integrity were investigated with variance decomposition methods. To test for neuroanatomical specificity, 16 specific tracts were additionally considered. We observed negative phenotypic correlations between epigenetic age acceleration and global white matter tract integrity (ρpheno=-0.119, p=0.028), with evidence of shared genetic (ρgene=-0.463, p=0.013) but not environmental influences. Negative phenotypic and genetic correlations with age acceleration were also seen for a number of specific white matter tracts, along with additional negative phenotypic correlations between granulocyte abundance and white matter integrity. These findings that increased acceleration in epigenetic age in peripheral blood correlates with reduced white matter integrity in the brain, and shares common genetic influences. provide a window into the neurobiology of aging processes within the brain and a potential biomarker of normal and pathological brain aging.SIGNIFICANCE STATEMENTEpigenetic measures can be used to predict age with a high degree of accuracy and so capture acceleration in biological age

  5. Normalised time-to-peak-distribution curves correlate with cerebral white matter hyperintensities - Could this improve early diagnosis?

    PubMed

    Nasel, Christian; Boubela, Roland; Kalcher, Klaudius; Moser, Ewald

    2017-02-01

    Parameter-free assessment of the time-to-peak (TTP) histogram, termed 'TTP-distribution curve' (TDC), of dynamic susceptibility contrast-enhanced magnetic resonance imaging (DSC-MRI) was introduced as a robust method to evaluate cerebral perfusion. TDC-assessment works fully automatically without the need of an arterial input function, thereby providing full comparability between different measurements. In the investigated sample of 106 patients, a strong dependency of TDC on the hemodynamic state of cerebral microvessels and the arterio-venous bolus-transit time [Formula: see text] was demonstrated. Accordingly, TDC-derived [Formula: see text] was 3.3-3.7 s for control patients and 4.4 s for cerebral small vessel disease patients. Measurements of associated bolus spread velocities ν and accelerations [Formula: see text] additionally revealed a direct effect from spin-spin relaxation time T2-weighted white matter hyperintensity volume, considered to indicate microangiopathy in cerebral small vessel disease, on the TDC-measurements. This strongly supports the prevailing hypothesis that cerebral small vessel disease directly influences DSC-measurements, where the degree could be estimated from an analysis of TDC. While this may be used to correct DSC-parameters for undesirable effects from cerebral small vessel disease, it could also serve to potentially identify patients at risk for cerebral small vessel disease at an early stage, since a subset of patients without yet significant WHM-volume, but clearly altered hemodynamics in TDC-measurements, was identified in this study.

  6. Normalised time-to-peak-distribution curves correlate with cerebral white matter hyperintensities – Could this improve early diagnosis?

    PubMed Central

    Boubela, Roland; Kalcher, Klaudius; Moser, Ewald

    2016-01-01

    Parameter-free assessment of the time-to-peak (TTP) histogram, termed ‘TTP-distribution curve’ (TDC), of dynamic susceptibility contrast-enhanced magnetic resonance imaging (DSC-MRI) was introduced as a robust method to evaluate cerebral perfusion. TDC-assessment works fully automatically without the need of an arterial input function, thereby providing full comparability between different measurements. In the investigated sample of 106 patients, a strong dependency of TDC on the hemodynamic state of cerebral microvessels and the arterio-venous bolus-transit time Tav was demonstrated. Accordingly, TDC-derived Tav was 3.3–3.7 s for control patients and 4.4 s for cerebral small vessel disease patients. Measurements of associated bolus spread velocities ν and accelerations a additionally revealed a direct effect from spin–spin relaxation time T2-weighted white matter hyperintensity volume, considered to indicate microangiopathy in cerebral small vessel disease, on the TDC-measurements. This strongly supports the prevailing hypothesis that cerebral small vessel disease directly influences DSC-measurements, where the degree could be estimated from an analysis of TDC. While this may be used to correct DSC-parameters for undesirable effects from cerebral small vessel disease, it could also serve to potentially identify patients at risk for cerebral small vessel disease at an early stage, since a subset of patients without yet significant WHM-volume, but clearly altered hemodynamics in TDC-measurements, was identified in this study. PMID:26823469

  7. Small white matter lesion detection in cerebral small vessel disease

    NASA Astrophysics Data System (ADS)

    Ghafoorian, Mohsen; Karssemeijer, Nico; van Uden, Inge; de Leeuw, Frank E.; Heskes, Tom; Marchiori, Elena; Platel, Bram

    2015-03-01

    Cerebral small vessel disease (SVD) is a common finding on magnetic resonance images of elderly people. White matter lesions (WML) are important markers for not only the small vessel disease, but also neuro-degenerative diseases including multiple sclerosis, Alzheimer's disease and vascular dementia. Volumetric measurements such as the "total lesion load", have been studied and related to these diseases. With respect to SVD we conjecture that small lesions are important, as they have been observed to grow over time and they form the majority of lesions in number. To study these small lesions they need to be annotated, which is a complex and time-consuming task. Existing (semi) automatic methods have been aimed at volumetric measurements and large lesions, and are not suitable for the detection of small lesions. In this research we established a supervised voxel classification CAD system, optimized and trained to exclusively detect small WMLs. To achieve this, several preprocessing steps were taken, which included a robust standardization of subject intensities to reduce inter-subject intensity variability as much as possible. A number of features that were found to be well identifying small lesions were calculated including multimodal intensities, tissue probabilities, several features for accurate location description, a number of second order derivative features as well as multi-scale annular filter for blobness detection. Only small lesions were used to learn the target concept via Adaboost using random forests as its basic classifiers. Finally the results were evaluated using Free-response receiver operating characteristic.

  8. Regional differences in cerebral asymmetries of human cortical white matter.

    PubMed

    Iwabuchi, Sarina J; Häberling, Isabelle S; Badzakova-Trajkov, Gjurgjica; Patston, Lucy L M; Waldie, Karen E; Tippett, Lynette J; Corballis, Michael C; Kirk, Ian J

    2011-11-01

    The form of the structural asymmetries across the cerebral hemispheres, that support well-established functional asymmetries, are not well understood. Although, many previous studies have investigated structural differences in areas associated with strong functional asymmetries, such as language processes, regions of the brain with less well established functional laterality have received less attention. The current study aims to address this by exploring global white matter asymmetries of the healthy human brain using diffusion tensor imaging (DTI) and tractography. DTI was conducted on twenty-nine healthy right-handed males, and pathways from the four major lobes were reconstructed using probabilistic tractography. Mean FA, parallel and perpendicular diffusion values were calculated and compared across hemispheres for each pathway generated. Significant asymmetries in the parietal (rightward asymmetry) and occipital (leftward asymmetry) pathways were found in FA measures. However, asymmetric patterns in parallel and/or perpendicular diffusion were observed in all four lobes, even in pathways with symmetrical FA. For instance, significant rightward asymmetry in parallel diffusion was found in the parietal and frontal lobes, whereas significant leftward asymmetry was found in the temporal and occipital lobes. We suggest that these different patterns of diffusion asymmetry reflect differences in microanatomy that support the known patterns of differential functional asymmetry. The different directions of anatomical asymmetry support the notion that there may be a number of different lateralising influences operating in the brain.

  9. Transfer function analysis of dynamic cerebral autoregulation: A white paper from the International Cerebral Autoregulation Research Network.

    PubMed

    Claassen, Jurgen A H R; Meel-van den Abeelen, Aisha S S; Simpson, David M; Panerai, Ronney B

    2016-04-01

    Cerebral autoregulation is the intrinsic ability of the brain to maintain adequate cerebral perfusion in the presence of blood pressure changes. A large number of methods to assess the quality of cerebral autoregulation have been proposed over the last 30 years. However, no single method has been universally accepted as a gold standard. Therefore, the choice of which method to employ to quantify cerebral autoregulation remains a matter of personal choice. Nevertheless, given the concept that cerebral autoregulation represents the dynamic relationship between blood pressure (stimulus or input) and cerebral blood flow (response or output), transfer function analysis became the most popular approach adopted in studies based on spontaneous fluctuations of blood pressure. Despite its sound theoretical background, the literature shows considerable variation in implementation of transfer function analysis in practice, which has limited comparisons between studies and hindered progress towards clinical application. Therefore, the purpose of the present white paper is to improve standardisation of parameters and settings adopted for application of transfer function analysis in studies of dynamic cerebral autoregulation. The development of these recommendations was initiated by (but not confined to) theCerebral Autoregulation Research Network(CARNet -www.car-net.org).

  10. Transfer function analysis of dynamic cerebral autoregulation: A white paper from the International Cerebral Autoregulation Research Network

    PubMed Central

    Meel-van den Abeelen, Aisha SS; Simpson, David M; Panerai, Ronney B

    2016-01-01

    Cerebral autoregulation is the intrinsic ability of the brain to maintain adequate cerebral perfusion in the presence of blood pressure changes. A large number of methods to assess the quality of cerebral autoregulation have been proposed over the last 30 years. However, no single method has been universally accepted as a gold standard. Therefore, the choice of which method to employ to quantify cerebral autoregulation remains a matter of personal choice. Nevertheless, given the concept that cerebral autoregulation represents the dynamic relationship between blood pressure (stimulus or input) and cerebral blood flow (response or output), transfer function analysis became the most popular approach adopted in studies based on spontaneous fluctuations of blood pressure. Despite its sound theoretical background, the literature shows considerable variation in implementation of transfer function analysis in practice, which has limited comparisons between studies and hindered progress towards clinical application. Therefore, the purpose of the present white paper is to improve standardisation of parameters and settings adopted for application of transfer function analysis in studies of dynamic cerebral autoregulation. The development of these recommendations was initiated by (but not confined to) the Cerebral Autoregulation Research Network (CARNet – www.car-net.org). PMID:26782760

  11. Cerebral White Matter Integrity Mediates Adult Age Differences in Cognitive Performance

    ERIC Educational Resources Information Center

    Madden, David J.; Spaniol, Julia; Costello, Matthew C.; Bucur, Barbara; White, Leonard E.; Cabeza, Roberto; Davis, Simon W.; Dennis, Nancy A.; Provenzale, James M.; Huettel, Scott A.

    2009-01-01

    Previous research has established that age-related decline occurs in measures of cerebral white matter integrity, but the role of this decline in age-related cognitive changes is not clear. To conclude that white matter integrity has a mediating (causal) contribution, it is necessary to demonstrate that statistical control of the white…

  12. Cerebral Blood Flow Heterogeneity in Preterm Sheep: Lack of Physiological Support for Vascular Boundary Zones in Fetal Cerebral White Matter

    PubMed Central

    McClure, Melissa; Riddle, Art; Manese, Mario; Luo, Ning Ling; Rorvik, Dawn A.; Kelly, Katherine A.; Barlow, Clyde H.; Kelly, Jeffrey J.; Vinecore, Kevin; Roberts, Colin; Hohimer, A. Roger; Back, Stephen A.

    2011-01-01

    Periventricular white matter (PVWM) injury is the leading cause of chronic neurological disability in survivors of prematurity. To address the role of cerebral ischemia in the pathogenesis of this injury, we tested the hypothesis that immaturity of spatially distal vascular “end” or “border” zones predisposes the PVWM to be more susceptible to falls in cerebral blood flow (CBF) than more proximal regions, such as the cerebral cortex. We used fluorescently-labeled microspheres to quantify regional CBF in situ in the 0.65 gestation fetal sheep in histopathologically-defined 3-dimensional regions by means of post hoc digital dissection and co-registration algorithms. Basal flow in PVWM was significantly lower than gyral white matter and cerebral cortex, but was equivalent in superficial, middle and deep PVWM. Absolute and relative CBF (expressed as percentage of basal) CBF did not differ during ischemia or reperfusion between the PVWM and more superficial gyral white matter or cortex. Moreover, CBF during ischemia and reperfusion was equivalent at three distinct levels of the PVWM. Absolute and relative CBF during ischemia and reperfusion was not predictive of the severity of PVWM injury, as defined by TUNEL staining. However, the magnitude of ischemia to the cerebral cortex directly correlated with lesion severity (r= −0.48, p<.05). Hence, the PVWM did not display unique CBF disturbances that accounted for the distribution of injury. These results suggest that previously-defined cellular-maturational factors have a greater influence on the vulnerability of PVWM to ischemic injury than the presence of immature vascular-boundary zones. PMID:18091757

  13. Oxidative Stress Interferes With White Matter Renewal After Prolonged Cerebral Hypoperfusion in Mice

    PubMed Central

    Miyamoto, Nobukazu; Maki, Takakuni; Pham, Loc-Duyen D.; Hayakawa, Kazuhide; Seo, Ji Hae; Mandeville, Emiri T.; Mandeville, Joseph B.; Kim, Kyu-Won; Lo, Eng H.; Arai, Ken

    2013-01-01

    Background and Purpose White matter injury caused by cerebral hypoperfusion may contribute to the pathophysiology of vascular dementia and stroke, but the underlying mechanisms remain to be fully defined. Here, we test the hypothesis that oxidative stress interferes with endogenous white matter repair by disrupting renewal processes mediated by oligodendrocyte precursor cells (OPCs). Methods In vitro, primary rat OPCs were exposed to sublethal CoCl2 for 7 days to induce prolonged chemical hypoxic stress. Then, OPC proliferation/differentiation was assessed. In vivo, prolonged cerebral hypoperfusion was induced by bilateral common carotid artery stenosis in mice. Then, reactive oxygen species production, myelin density, oligodendrocyte versus OPC counts, and cognitive function were evaluated. To block oxidative stress, OPCs and mice were treated with the radical scavenger edaravone. Results Prolonged chemical hypoxic stress suppressed OPC differentiation in vitro. Radical scavenging with edaravone ameliorated these effects. After 28 days of cerebral hypoperfusion in vivo, reactive oxygen species levels were increased in damaged white matter, along with the suppression of OPC-to-oligodendrocyte differentiation and loss of myelin staining. Concomitantly, mice showed functional deficits in working memory. Radical scavenging with edaravone rescued OPC differentiation, ameliorated myelin loss, and restored working memory function. Conclusions Our proof-of-concept study demonstrates that after prolonged cerebral hypoperfusion, oxidative stress interferes with white matter repair by disrupting OPC renewal mechanisms. Radical scavengers may provide a potential therapeutic approach for white matter injury in vascular dementia and stroke. PMID:24072001

  14. Connectivity-driven white matter scaling and folding in primate cerebral cortex

    PubMed Central

    Herculano-Houzel, Suzana; Mota, Bruno; Kaas, Jon H.

    2010-01-01

    Larger brains have an increasingly folded cerebral cortex whose white matter scales up faster than the gray matter. Here we analyze the cellular composition of the subcortical white matter in 11 primate species, including humans, and one Scandentia, and show that the mass of the white matter scales linearly across species with its number of nonneuronal cells, which is expected to be proportional to the total length of myelinated axons in the white matter. This result implies that the average axonal cross-section area in the white matter, a, does not scale significantly with the number of neurons in the gray matter, N. The surface area of the white matter increases with N0.87, not N1.0. Because this surface can be defined as the product of N, a, and the fraction n of cortical neurons connected through the white matter, we deduce that connectivity decreases in larger cerebral cortices as a slowly diminishing fraction of neurons, which varies with N−0.16, sends myelinated axons into the white matter. Decreased connectivity is compatible with previous suggestions that neurons in the cerebral cortex are connected as a small-world network and should slow down the increase in global conduction delay in cortices with larger numbers of neurons. Further, a simple model shows that connectivity and cortical folding are directly related across species. We offer a white matter-based mechanism to account for increased cortical folding across species, which we propose to be driven by connectivity-related tension in the white matter, pulling down on the gray matter. PMID:20956290

  15. APOE/TOMM 40 genetic loci, white matter hyperintensities, and cerebral microbleeds

    PubMed Central

    Lyall, Donald M.; Muñoz Maniega, Susana; Harris, Sarah E.; Bastin, Mark E.; Murray, Catherine; Lutz, Michael W.; Saunders, Ann M.; Roses, Allen D.; Valdés Hernández, Maria del C.; Royle, Natalie A.; Starr, John M.; Porteous, David J.; Deary, Ian J.

    2015-01-01

    Background Two markers of cerebral small vessel disease are white matter hyperintensities and cerebral microbleeds, which commonly occur in people with Alzheimer's disease. Aim and/or hypothesis To test for independent associations between two Alzheimer's disease‐susceptibility gene loci – APOE ε and the TOMM 40 ‘523’ poly‐T repeat – and white matter hyperintensities/cerebral microbleed burden in community‐dwelling older adults. Methods Participants in the Lothian Birth Cohort 1936 underwent genotyping for APOE ε and TOMM 40 523, and detailed structural brain magnetic resonance imaging at a mean age of 72·70 years (standard deviation = 0·7; range = 71–74). Results No significant effects of APOE ε or TOMM 40 523 genotypes on white matter hyperintensities or cerebral microbleed burden were found amongst 624 participants. Conclusions Lack of association between two Alzheimer's disease susceptibility gene loci and markers of cerebral small vessel disease may reflect the relative health of this population compared with those in other studies in the literature. PMID:26310205

  16. Computer Modeling of Acceleration Effects on Cerebral Oxygen Saturation

    DTIC Science & Technology

    2007-04-01

    a significant physiological threat to etrate the cranium and enter the cerebral cortex. Hongo high-performance aircraft pilots since the development...et al. and Hongo et al. (7,8). blackened out and all that could be seen was the target, The primary focus of this effort was to build a model i.e...O6GInduced.html. 87:402. 12. Tripp LD, Arnold A, Bagian J, et al. Psychophysiological effects 8. Hongo K, Kobayashi S, Okudera H, et al. Noninvasive cerebral of

  17. Cerebral White Matter Integrity and Cognitive Aging: Contributions from Diffusion Tensor Imaging

    PubMed Central

    Madden, David J.; Bennett, Ilana J.; Song, Allen W.

    2009-01-01

    The integrity of cerebral white matter is critical for efficient cognitive functioning, but little is known regarding the role of white matter integrity in age-related differences in cognition. Diffusion tensor imaging (DTI) measures the directional displacement of molecular water and as a result can characterize the properties of white matter that combine to restrict diffusivity in a spatially coherent manner. This review considers DTI studies of aging and their implications for understanding adult age differences in cognitive performance. Decline in white matter integrity contributes to a disconnection among distributed neural systems, with a consistent effect on perceptual speed and executive functioning. The relation between white matter integrity and cognition varies across brain regions, with some evidence suggesting that age-related effects exhibit an anterior-posterior gradient. With continued improvements in spatial resolution and integration with functional brain imaging, DTI holds considerable promise, both for theories of cognitive aging and for translational application. PMID:19705281

  18. Reversible cerebral periventricular white matter changes with corpus callosum involvement in acute toluene-poisoning.

    PubMed

    Lin, Chih-Ming; Liu, Chi-Kuang

    2015-01-01

    Substance poisoning, such as toluene intoxication, has seldom been reported in the relevant literature. The documented cerebral neuroimaging has mostly described reversible symmetrical white matter changes in both the cerebral and cerebellar hemispheres. This paper presents 2 patients with toluene poisoning, whose brain magnetic resonance imaging studies showed a similar picture that included extra involvement over the corpus callosum; however, such corpus callosum involvement has never been mentioned and is quite rare in the literature. We discussed the underlying neuropathological pathways in this article. Hopefully, these cases will provide first-line clinicians with some valuable information with regard to toluene intoxication and clinical neuroimaging presentations.

  19. Microstructure and Cerebral Blood Flow within White Matter of the Human Brain: A TBSS Analysis

    PubMed Central

    Giezendanner, Stéphanie; Fisler, Melanie Sarah; Soravia, Leila Maria; Andreotti, Jennifer; Walther, Sebastian; Wiest, Roland; Dierks, Thomas; Federspiel, Andrea

    2016-01-01

    Background White matter (WM) fibers connect different brain regions and are critical for proper brain function. However, little is known about the cerebral blood flow in WM and its relation to WM microstructure. Recent improvements in measuring cerebral blood flow (CBF) by means of arterial spin labeling (ASL) suggest that the signal in white matter may be detected. Its implications for physiology needs to be extensively explored. For this purpose, CBF and its relation to anisotropic diffusion was analyzed across subjects on a voxel-wise basis with tract-based spatial statistics (TBSS) and also across white matter tracts within subjects. Methods Diffusion tensor imaging and ASL were acquired in 43 healthy subjects (mean age = 26.3 years). Results CBF in WM was observed to correlate positively with fractional anisotropy across subjects in parts of the splenium of corpus callosum, the right posterior thalamic radiation (including the optic radiation), the forceps major, the right inferior fronto-occipital fasciculus, the right inferior longitudinal fasciculus and the right superior longitudinal fasciculus. Furthermore, radial diffusivity correlated negatively with CBF across subjects in similar regions. Moreover, CBF and FA correlated positively across white matter tracts within subjects. Conclusion The currently observed findings on a macroscopic level might reflect the metabolic demand of white matter on a microscopic level involving myelination processes or axonal function. However, the exact underlying physiological mechanism of this relationship needs further evaluation. PMID:26942763

  20. Detection of white matter lesions in cerebral small vessel disease

    NASA Astrophysics Data System (ADS)

    Riad, Medhat M.; Platel, Bram; de Leeuw, Frank-Erik; Karssemeijer, Nico

    2013-02-01

    White matter lesions (WML) are diffuse white matter abnormalities commonly found in older subjects and are important indicators of stroke, multiple sclerosis, dementia and other disorders. We present an automated WML detection method and evaluate it on a dataset of small vessel disease (SVD) patients. In early SVD, small WMLs are expected to be of importance for the prediction of disease progression. Commonly used WML segmentation methods tend to ignore small WMLs and are mostly validated on the basis of total lesion load or a Dice coefficient for all detected WMLs. Therefore, in this paper, we present a method that is designed to detect individual lesions, large or small, and we validate the detection performance of our system with FROC (free-response ROC) analysis. For the automated detection, we use supervised classification making use of multimodal voxel based features from different magnetic resonance imaging (MRI) sequences, including intensities, tissue probabilities, voxel locations and distances, neighborhood textures and others. After preprocessing, including co-registration, brain extraction, bias correction, intensity normalization, and nonlinear registration, ventricle segmentation is performed and features are calculated for each brain voxel. A gentle-boost classifier is trained using these features from 50 manually annotated subjects to give each voxel a probability of being a lesion voxel. We perform ROC analysis to illustrate the benefits of using additional features to the commonly used voxel intensities; significantly increasing the area under the curve (Az) from 0.81 to 0.96 (p<0.05). We perform the FROC analysis by testing our classifier on 50 previously unseen subjects and compare the results with manual annotations performed by two experts. Using the first annotator results as our reference, the second annotator performs at a sensitivity of 0.90 with an average of 41 false positives per subject while our automated method reached the same

  1. Effects of Surgery and Proton Therapy on Cerebral White Matter of Craniopharyngioma Patients

    SciTech Connect

    Uh, Jinsoo; Merchant, Thomas E.; Li, Yimei; Li, Xingyu; Sabin, Noah D.; Indelicato, Daniel J.; Ogg, Robert J.; Boop, Frederick A.; Jane, John A.; Hua, Chiaho

    2015-09-01

    Purpose: The purpose of this study was to determine radiation dose effect on the structural integrity of cerebral white matter in craniopharyngioma patients receiving surgery and proton therapy. Methods and Materials: Fifty-one patients (2.1-19.3 years of age) with craniopharyngioma underwent surgery and proton therapy in a prospective therapeutic trial. Anatomical magnetic resonance images acquired after surgery but before proton therapy were inspected to identify white matter structures intersected by surgical corridors and catheter tracks. Longitudinal diffusion tensor imaging (DTI) was performed to measure microstructural integrity changes in cerebral white matter. Fractional anisotropy (FA) derived from DTI was statistically analyzed for 51 atlas-based white matter structures of the brain to determine radiation dose effect. FA in surgery-affected regions in the corpus callosum was compared to that in its intact counterpart to determine whether surgical defects affect radiation dose effect. Results: Surgical defects were seen most frequently in the corpus callosum because of transcallosal resection of tumors and insertion of ventricular or cyst catheters. Longitudinal DTI data indicated reductions in FA 3 months after therapy, which was followed by a recovery in most white matter structures. A greater FA reduction was correlated with a higher radiation dose in 20 white matter structures, indicating a radiation dose effect. The average FA in the surgery-affected regions before proton therapy was smaller (P=.0001) than that in their non–surgery-affected counterparts with more intensified subsequent reduction of FA (P=.0083) after therapy, suggesting that surgery accentuated the radiation dose effect. Conclusions: DTI data suggest that mild radiation dose effects occur in patients with craniopharyngioma receiving surgery and proton therapy. Surgical defects present at the time of proton therapy appear to accentuate the radiation dose effect longitudinally

  2. Outcome of cerebral arteriovenous malformations after linear accelerator reirradiation

    PubMed Central

    Moraes, Paulo L.; Dias, Rodrigo S.; Weltman, Eduardo; Giordani, Adelmo J.; Benabou, Salomon; Segreto, Helena R. C.; Segreto, Roberto A.

    2015-01-01

    Background: The aim of this study was to evaluate the clinical outcome of patients undergoing single-dose reirradiation using the Linear Accelerator (LINAC) for brain arteriovenous malformations (AVM). Methods: A retrospective study of 37 patients with brain AVM undergoing LINAC reirradiation between April 2003 and November 2011 was carried out. Patient characteristics, for example, gender, age, use of medications, and comorbidities; disease characteristics, for example, Spetzler–Martin grading system, location, volume, modified Pollock–Flickinger score; and treatment characteristics, for example, embolization, prescription dose, radiation dose–volume curves, and conformity index were analyzed. During the follow-up period, imaging studies were performed to evaluate changes after treatment and AVM cure. Complications, such as edema, rupture of the blood–brain barrier, and radionecrosis were classified as symptomatic and asymptomatic. Results: Twenty-seven patients underwent angiogram after reirradiation and the percentage of angiographic occlusion was 55.5%. In three patients without obliteration, AVM shrinkage made it possible to perform surgical resection with a 2/3 cure rate. A reduction in AVM nidus volume greater than 50% after the first procedure was shown to be the most important predictor of obliteration. Another factor associated with AVM cure was a prescription dose higher than 15.5 Gy in the first radiosurgery. Two patients had permanent neurologic deficits. Factors correlated with complications were the prescription dose and maximum dose in the first procedure. Conclusion: This study suggests that single-dose reirradiation is safe and feasible in partially occluded AVM. Reirradiation may not benefit candidates whose prescribed dose was lower than 15.5 Gy in the first procedure and initial AVM nidus volume did not decrease by more than 50% before reirradiation. PMID:26110078

  3. Cerebral White Matter Integrity Mediates Adult Age Differences in Cognitive Performance

    PubMed Central

    Madden, David J.; Spaniol, Julia; Costello, Matthew C.; Bucur, Barbara; White, Leonard E.; Cabeza, Roberto; Davis, Simon W.; Dennis, Nancy A.; Provenzale, James M.; Huettel, Scott A.

    2009-01-01

    Previous research has established that age-related decline occurs in measures of cerebral white matter integrity, but the role of this decline in age-related cognitive changes is not clear. To conclude that white matter integrity has a mediating (causal) contribution, it is necessary to demonstrate that statistical control of the white matter-cognition relation reduces the magnitude of age-cognition relation. In this research, we tested the mediating role of white matter integrity, in the context of a task switching paradigm involving word categorization. Participants were 20 healthy, community-dwelling older adults (60–85 years), and 20 younger adults (18–27 years). From diffusion tensor imaging (DTI) tractography, we obtained fractional anisotropy (FA) as an index of white matter integrity in the genu and splenium of the corpus callosum and the superior longitudinal fasciculus (SLF). Mean FA values exhibited age-related decline consistent with a decrease in white matter integrity. From a model of reaction time distributions, we obtained independent estimates of the decisional and nondecisional (perceptual-motor) components of task performance. Age-related decline was evident in both components. Critically, age differences in task performance were mediated by FA in two regions: the central portion of the genu, and splenium-parietal fibers in the right hemisphere. This relation held only for the decisional component and was not evident in the nondecisional component. This result is the first demonstration that the integrity of specific white matter tracts is a mediator of age-related changes in cognitive performance. PMID:18564054

  4. Accelerated development of cerebral small vessel disease in young stroke patients

    PubMed Central

    Arntz, Renate M.; van den Broek, Steffen M.A.; van Uden, Inge W.M.; Ghafoorian, Mohsen; Platel, Bram; Rutten-Jacobs, Loes C.A.; Maaijwee, Noortje A.M.; Schaapsmeerders, Pauline; Schoonderwaldt, Hennie C.; van Dijk, Ewoud J.

    2016-01-01

    Objective: To study the long-term prevalence of small vessel disease after young stroke and to compare this to healthy controls. Methods: This prospective cohort study comprises 337 patients with an ischemic stroke or TIA, aged 18–50 years, without a history of TIA or stroke. In addition, 90 age- and sex-matched controls were included. At follow-up, lacunes, microbleeds, and white matter hyperintensity (WMH) volume were assessed using MRI. To investigate the relation between risk factors and small vessel disease, logistic and linear regression were used. Results: After mean follow-up of 9.9 (SD 8.1) years, 337 patients were included (227 with an ischemic stroke and 110 with a TIA). Mean age of patients was 49.8 years (SD 10.3) and 45.4% were men; for controls, mean age was 49.4 years (SD 11.9) and 45.6% were men. Compared with controls, patients more often had at least 1 lacune (24.0% vs 4.5%, p < 0.0001). In addition, they had a higher WMH volume (median 1.5 mL [interquartile range (IQR) 0.5–3.7] vs 0.4 mL [IQR 0.0–1.0], p < 0.001). Compared with controls, patients had the same volume WMHs on average 10–20 years earlier. In the patient group, age at stroke (β = 0.03, 95% confidence interval [CI] 0.02–0.04) hypertension (β = 0.22, 95% CI 0.04–0.39), and smoking (β = 0.18, 95% CI 0.01–0.34) at baseline were associated with WMH volume. Conclusions: Patients with a young stroke have a higher burden of small vessel disease than controls adjusted for confounders. Cerebral aging seems accelerated by 10–20 years in these patients, which may suggest an increased vulnerability to vascular risk factors. PMID:27521431

  5. White matter tract and glial-associated changes in 5-hydroxymethylcytosine following chronic cerebral hypoperfusion.

    PubMed

    Tsenkina, Yanina; Ruzov, Alexey; Gliddon, Catherine; Horsburgh, Karen; De Sousa, Paul A

    2014-12-10

    White matter abnormalities due to age-related cerebrovascular alterations is a common pathological hallmark associated with functional impairment in the elderly which has been modeled in chronically hypoperfused mice. 5-Methylcytosine (5mC) and its oxidized derivative 5-hydroxymethylcytosine (5hmC) are DNA modifications that have been recently linked with age-related neurodegeneration and cerebrovascular pathology. Here we conducted a pilot investigation of whether chronic cerebral hypoperfusion might affect genomic distribution of these modifications and/ or a Ten-Eleven Translocation protein 2 (TET2) which catalyses hydroxymethylation in white and grey matter regions of this animal model. Immunohistochemical evaluation of sham and chronically hypoperfused mice a month after surgery revealed significant (p<0.05) increases in the proportion of 5hmC positive cells, Iba1 positive inflammatory microglia, and NG2 positive oligodendroglial progenitors in the hypoperfused corpus callosum. In the same white matter tract there was an absence of hypoperfusion-induced alterations in the proportion of 5mC, TET2 positive cells and CC1 positive mature oligodrendrocytes. Correlation analysis across animals within both treatment groups demonstrated a significant association of the elevated 5hmC levels with increases in the proportion of inflammatory microglia only (p=0.01) in the corpus callosum. In vitro studies revealed that 5hmC is lost during oligodendroglial maturation but not microglial activation. Additionally, TET1, TET2, and TET3 protein levels showed dynamic alterations during oligodendroglial development and following oxidative stress in vitro. Our study suggests that 5hmC exhibits white matter tract and cell type specific dynamics following chronic cerebral hypoperfusion in mice.

  6. Study on constant-step stress accelerated life tests in white organic light-emitting diodes.

    PubMed

    Zhang, J P; Liu, C; Chen, X; Cheng, G L; Zhou, A X

    2014-11-01

    In order to obtain reliability information for a white organic light-emitting diode (OLED), two constant and one step stress tests were conducted with its working current increased. The Weibull function was applied to describe the OLED life distribution, and the maximum likelihood estimation (MLE) and its iterative flow chart were used to calculate shape and scale parameters. Furthermore, the accelerated life equation was determined using the least squares method, a Kolmogorov-Smirnov test was performed to assess if the white OLED life follows a Weibull distribution, and self-developed software was used to predict the average and the median lifetimes of the OLED. The numerical results indicate that white OLED life conforms to a Weibull distribution, and that the accelerated life equation completely satisfies the inverse power law. The estimated life of a white OLED may provide significant guidelines for its manufacturers and customers.

  7. Acceleration of ventricular rate by fibrillation associated with the Wolff-Parkinson-White syndrome.

    PubMed

    Sheinman, B D; Evans, T

    1982-10-09

    Amiodarone has proved to be a valuable drug in atrial fibrillation associated with the Wolff-Parkinson-White syndrome. When it was administered to a patient with this syndrome in atrial fibrillation, who had previously suffered an inferior myocardial infarction, the ventricular rate accelerated from 170 to 230 beats/minute.This unusual case emphasises the need for full electrophysiological assessment of patients with the Wolff-Parkinson-White syndrome for whom amiodarone treatment is being considered.

  8. Protective effects of carnosine on white matter damage induced by chronic cerebral hypoperfusion

    PubMed Central

    Ma, Jing; Bo, Shu-hong; Lu, Xiao-tong; Xu, A-jing; Zhang, Jian

    2016-01-01

    Carnosine is a dipeptide that scavenges free radicals, inhibits inflammation in the central nervous system, and protects against ischemic and hypoxic brain damage through its anti-oxidative and anti-apoptotic actions. Therefore, we hypothesized that carnosine would also protect against white matter damage caused by subcortical ischemic injury. White matter damage was induced by right unilateral common carotid artery occlusion in mice. The animals were treated with 200, 500 or 750 mg/kg carnosine by intraperitoneal injection 30 minutes before injury and every other day after injury. Then, 37 days later, Klüver-Barrera staining, toluidine blue staining and immunofluorescence staining were performed. Carnosine (200, 500 mg/kg) substantially reduced damage to the white matter in the corpus callosum, internal capsule and optic tract, and it rescued expression of myelin basic protein, and alleviated the loss of oligodendrocytes. However, carnosine at the higher dose of 750 mg/kg did not have the same effects as the 200 and 500 mg/kg doses. These findings show that carnosine, at a particular dose range, protects against white matter damage caused by chronic cerebral ischemia in mice, likely by reducing oligodendroglial cell loss. PMID:27857746

  9. Decreased and Increased Anisotropy along Major Cerebral White Matter Tracts in Preterm Children and Adolescents

    PubMed Central

    Ben-Shachar, Michal; Feldman, Heidi M.

    2015-01-01

    Premature birth is highly prevalent and associated with neurodevelopmental delays and disorders. Adverse outcomes, particularly in children born before 32 weeks of gestation, have been attributed in large part to white matter injuries, often found in periventricular regions using conventional imaging. To date, tractography studies of white matter pathways in children and adolescents born preterm have evaluated only a limited number of tracts simultaneously. The current study compares diffusion properties along 18 major cerebral white matter pathways in children and adolescents born preterm (n = 27) and full term (n = 19), using diffusion magnetic resonance imaging and tractography. We found that compared to the full term group, the preterm group had significantly decreased FA in segments of the bilateral uncinate fasciculus and anterior segments of the right inferior fronto-occipital fasciculus. Additionally, the preterm group had significantly increased FA in segments of the right and left anterior thalamic radiations, posterior segments of the right inferior fronto-occipital fasciculus, and the right and left inferior longitudinal fasciculus. Increased FA in the preterm group was generally associated with decreased radial diffusivity. These findings indicate that prematurity-related white matter differences in later childhood and adolescence do not affect all tracts in the periventricular zone and can involve both decreased and increased FA. Differences in the patterns of radial diffusivity and axial diffusivity suggest that the tissue properties underlying group FA differences may vary within and across white matter tracts. Distinctive diffusion properties may relate to variations in the timing of injury in the neonatal period, extent of white matter dysmaturity and/or compensatory processes in childhood. PMID:26560745

  10. Long-term cerebral white and gray matter changes after preeclampsia

    PubMed Central

    Siepmann, Timo; Boardman, Henry; Bilderbeck, Amy; Griffanti, Ludovica; Kenworthy, Yvonne; Zwager, Charlotte; McKean, David; Francis, Jane; Neubauer, Stefan; Yu, Grace Z.; Lewandowski, Adam J.; Sverrisdottir, Yrsa Bergmann

    2017-01-01

    Objective: To determine whether changes in cerebral structure are present after preeclampsia that may explain increased cerebrovascular risk in these women. Methods: We conducted a case control study in women between 5 and 15 years after either a preeclamptic or normotensive pregnancy. Brain MRI was performed. Analysis of white matter structure was undertaken using voxel-based segmentation of fluid-attenuation inversion recovery sequences to assess white matter lesion volume and diffusion tensor imaging to measure microstructural integrity. Voxel-based analysis of gray matter volumes was performed with adjustment for skull size. Results: Thirty-four previously preeclamptic women (aged 42.8 ± 5.1 years) and 49 controls were included. Previously preeclamptic women had reduced cortical gray matter volume (523.2 ± 30.1 vs 544.4 ± 44.7 mL, p < 0.05) and, although both groups displayed white matter lesions, changes were more extensive in previously preeclamptic women. They displayed increased temporal lobe white matter disease (lesion volume: 23.2 ± 24.9 vs 10.9 ± 15.0 μL, p < 0.05) and altered microstructural integrity (radial diffusivity: 538 ± 19 vs 526 ± 18 × 10−6 mm2/s, p < 0.01), which also extended to occipital and parietal lobes. The degree of temporal lobe white matter change in previously preeclamptic women was independent of their current cardiovascular risk profile (p < 0.05) and increased with time from index pregnancy (p < 0.05). Conclusion: A history of preeclampsia is associated with temporal lobe white matter changes and reduced cortical volume in young women, which is out of proportion to their classic cardiovascular risk profile. The severity of changes is proportional to time since pregnancy, which would be consistent with continued accumulation of damage after pregnancy. PMID:28235810

  11. Photoperiodic Regulation of Cerebral Blood Flow in White-Footed Mice (Peromyscus leucopus)

    PubMed Central

    Teplitsky, Seth

    2016-01-01

    Abstract Individuals living outside the tropics need to adjust their behavioral and physiological repertoires throughout the year to adapt to the changing seasons. White-footed mice (Peromyscus leucopus) reduce hippocampal volumes, hippocampal-dependent memory function, long-term potentiation, and alter neurogenesis in response to short (winter-like) day lengths (photoperiods). During winter, these mice putatively shunt energy away from the brain to maximize peripheral thermogenesis, immune function, and survival. We hypothesized that these changes in brain function are accompanied by alterations in brain vasculature. We maintained white-footed mice in short (8 h light/16 h dark) or long (16 h light/8 h dark) photoperiods for 8–9 weeks. Mice were then perfused with fluorescein isothiocyanate (FITC)-conjugated tomato (Lycopersicon esculentum) lectin to visualize the perfused cerebrovasculature. Short-day mice reduced hippocampal and cortical capillary density (FITC+ area); vessels isolated from short day-exposed mice expressed higher mRNA levels of the gelatinase matrix metalloproteinase 2 (MMP2). Additionally, short-day mice reduced cerebral blood flow ∼15% compared with their long-day counterparts, as assessed by laser speckle flowmetry. Immunohistochemistry revealed higher levels of MMP2 in the hippocampus of mice maintained in short days compared with long days, potentially contributing to the observed vascular remodeling. These data demonstrate that a discrete environmental signal (i.e., day length) can substantially alter cerebral blood flow in adult mammals. PMID:27570829

  12. Higher subcortical and white matter cerebral blood flow in perinatally HIV-infected children

    PubMed Central

    Blokhuis, Charlotte; Mutsaerts, Henri J.M.M.; Cohen, Sophie; Scherpbier, Henriëtte J.; Caan, Matthan W.A.; Majoie, Charles B.L.M.; Kuijpers, Taco W.; Reiss, Peter; Wit, Ferdinand W.N.M.; Pajkrt, Dasja

    2017-01-01

    Abstract This study aimed to evaluate cerebral blood flow (CBF) in pediatric human immunodeficiency virus (HIV)-infection, and its role in HIV-related cerebral injury and cognitive impairment. This cross-sectional observational study compared 28 perinatally HIV-infected children (8–18 years) to 34 healthy controls matched for age, sex, ethnicity, and socio-economic status. All participants underwent 3-Tesla magnetic resonance imaging, using arterial spin labeling to assess CBF in gray matter (GM), white matter (WM), basal ganglia, and thalamus. We used linear regression analysis to evaluate group differences and associations with HIV disease and treatment characteristics, macrostructural (volume loss, WM lesions) or microstructural injury (increased WM diffusivity, neurometabolite alterations), or poorer cognitive performance. HIV-infected children had higher CBF in WM (+10.2%; P = 0.042), caudate nucleus (+4.8%; P = 0.002), putamen (+3.6%; P = 0.017), nucleus accumbens (+3.9%; P = 0.031), and thalamus (+5.5%; P = 0.032). Thalamus CBF was highest in children with a Centers for Disease Control and Prevention stage B (Coef. = 6.45; P = 0.005) or C (Coef. = 8.52; P = 0.001) diagnosis. Lower GM CBF was associated with higher WM lesion volume in HIV-infected children (Coef. = −0.053; P = 0.001). No further associations with HIV-related cognitive impairment or cerebral injury were found. CBF was higher in WM, basal ganglia, and thalamus in combination antiretroviral therapy (cART)-treated perinatally HIV-infected children, but this was not associated with cerebral injury or cognitive impairment. HIV-infected children with lower GM CBF had a higher volume of WM lesions, which could reflect vascular disease as potential contributing factor to white matter injury. Lifelong exposure to HIV and cART in this population warrants longitudinal assessment of CBF and how it relates to (neuro)inflammation, vascular dysfunction, and

  13. Pharmacological Effects of Erythropoietin and its Derivative Carbamyl erythropoietin in Cerebral White Matter Injury

    NASA Astrophysics Data System (ADS)

    Liu, Wei

    Periventricular leukomalacia (PVL) is the predominant form of brain injury in the premature infant and the most common cause of cerebral palsy, yet no therapy currently exists for this serious human disorder. As PVL often occurs in preterm infants suffering from cerebral hypoxia/ischemia with or without prior exposure to maternal-fetal infection/inflammation, we used hypoxia/ischemia with or without lipopolysaccharide (LPS) injection, to produce clinically relevant PVL-like lesions in the white matter in postnatal day six (P6) mice. We studied the white matter pathology under different conditions, such as different durations of hypoxia and different doses of LPS, to evaluate the effects of those etiological factors on neonatal white matter injury. Distinct related pathological events were investigated at different time points during the progression of PVL. We used immunohistochemistry, histological analysis, and electron microscopy (EM) to study demylination that occurs in the white matter area, which is consistent with the pathology of human PVL. Previous studies have shown that erythropoietin (EPO) and its derivative carbamylated EPO (CEPO) are neuroprotective in various experimental models of brain injury. However, none of these studies investigated their efficacy against white matter injury using appropriate animal models of PVL. We produced unilateral or bilateral white matter injury in P6 mice using unilateral carotid ligation (UCL) followed by hypoxia (6% oxygen, 35 min) or by UCL/hypoxia plus LPS injection, respectively. We administered a single intraperitoneal (i.p.) dose of EPO or CEPO (5000 IU/kg) immediately after the insult, and found both drugs to provide significant protection against white matter injury in PVL mice compared to vehicle-treated groups. In addition, EPO and CEPO treatments attenuated neurobehavioral dysfunctions in an acute manner after PVL injury. EPO and CEPO have relatively few adverse effects, and thus may be a therapeutic agent

  14. Spatial patterns of whole brain grey and white matter injury in patients with occult spastic diplegic cerebral palsy.

    PubMed

    Mu, Xuetao; Nie, Binbin; Wang, Hong; Duan, Shaofeng; Zhang, Zan; Dai, Guanghui; Ma, Qiaozhi; Shan, Baoci; Ma, Lin

    2014-01-01

    Spastic diplegic cerebral palsy (SDCP) is a common type of cerebral palsy (CP), which presents as a group of motor-impairment syndromes. Previous conventional MRI studies have reported abnormal structural changes in SDCP, such as periventricular leucomalacia. However, there are roughly 27.8% SDCP patients presenting normal appearance in conventional MRI, which were considered as occult SDCP. In this study, sixteen patients with occult SDCP and 16 age- and sex-matched healthy control subjects were collected and the data were acquired on a 3T MR system. We applied voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) analysis to investigate whole brain grey and white matter injury in occult SDCP. By using VBM method, the grey matter volume reduction was revealed in the bilateral basal ganglia regions, thalamus, insula, and left cerebral peduncle, whereas the white matter atrophy was found to be located in the posterior part of corpus callosum and right posterior corona radiata in the occult SDCP patients. By using TBSS, reduced fractional anisotropy (FA) values were detected in multiple white matter regions, including bilateral white matter tracts in prefrontal lobe, temporal lobe, internal and external capsule, corpus callosum, cingulum, thalamus, brainstem and cerebellum. Additionally, several regions of white matter tracts injury were found to be significantly correlated with motor dysfunction. These results collectively revealed the spatial patterns of whole brain grey and white matter injury in occult SDCP.

  15. Comparison of the Relationship between Cerebral White Matter and Grey Matter in Normal Dogs and Dogs with Lateral Ventricular Enlargement.

    PubMed

    Schmidt, Martin J; Laubner, Steffi; Kolecka, Malgorzata; Failing, Klaus; Moritz, Andreas; Kramer, Martin; Ondreka, Nele

    2015-01-01

    Large cerebral ventricles are a frequent finding in brains of dogs with brachycephalic skull conformation, in comparison with mesaticephalic dogs. It remains unclear whether oversized ventricles represent a normal variant or a pathological condition in brachycephalic dogs. There is a distinct relationship between white matter and grey matter in the cerebrum of all eutherian mammals. The aim of this study was to determine if this physiological proportion between white matter and grey matter of the forebrain still exists in brachycephalic dogs with oversized ventricles. The relative cerebral grey matter, white matter and cerebrospinal fluid volume in dogs were determined based on magnetic-resonance-imaging datasets using graphical software. In an analysis of covariance (ANCOVA) using body mass as the covariate, the adjusted means of the brain tissue volumes of two groups of dogs were compared. Group 1 included 37 mesaticephalic dogs of different sizes with no apparent changes in brain morphology, and subjectively normal ventricle size. Group 2 included 35 brachycephalic dogs in which subjectively enlarged cerebral ventricles were noted as an incidental finding in their magnetic-resonance-imaging examination. Whereas no significant different adjusted means of the grey matter could be determined, the group of brachycephalic dogs had significantly larger adjusted means of lateral cerebral ventricles and significantly less adjusted means of relative white matter volume. This indicates that brachycephalic dogs with subjective ventriculomegaly have less white matter, as expected based on their body weight and cerebral volume. Our study suggests that ventriculomegaly in brachycephalic dogs is not a normal variant of ventricular volume. Based on the changes in the relative proportion of WM and CSF volume, and the unchanged GM proportions in dogs with ventriculomegaly, we rather suggest that distension of the lateral ventricles might be the underlying cause of pressure

  16. Cryptococcal meningitis accompanying lymphocytic inflammation predominantly in cerebral deep white matter: a possible manifestation of immune reconstitution inflammatory syndrome.

    PubMed

    Kuwahara, Hiroya; Tsuchiya, Kuniaki; Kobayashi, Zen; Inaba, Akira; Akiyama, Haruhiko; Mizusawa, Hidehiro

    2014-02-01

    Cryptococcal meningitis is rarely complicated by immune-mediated leukoencephalopathy, but the precise pathomechanism is uncertain. A 72-year-old Japanese man treated with prednisolone for Sweet disease developed a subacute progression of meningitis, which was considered as neuro-Sweet disease. A treatment by methylprednisolone rapidly improved CSF findings with a remarkable decrease in lymphocyte numbers in the blood, but the patient's consciousness still worsened after the cessation of the treatment. The patient developed cryptococcal meningitis and MRI showed abnormal intensities predominantly in the cerebral deep white matter along with the recovery of lymphocyte numbers in the blood, which resulted in death. A postmortem examination of the brain revealed degenerative lesions, especially at the cerebral white matter and cortex adjacent to the leptomeninges abundantly infiltrated by Cryptococcus neoformans. In the affected cerebral deep white matter, perivascular infiltration of lymphocytes was prominent in coexistence with reactive astrocytes and vascular proliferation, but these findings were not observed in the subcortical and cortical lesions. Cryptococcus neoformans was not present within the brain parenchyma. This is the first report of a case suggesting that cryptococcal meningitis can accompany lymphocytic inflammation predominantly in cerebral deep white matter as a possible manifestation of immune reconstitution inflammatory syndrome.

  17. Intranasal Insulin Prevents Cognitive Decline, Cerebral Atrophy and White Matter Changes in Murine Type I Diabetic Encephalopathy

    ERIC Educational Resources Information Center

    Francis, George J.; Martinez, Jose A.; Liu, Wei Q.; Xu, Kevin; Ayer, Amit; Fine, Jared; Tuor, Ursula I.; Glazner, Gordon; Hanson, Leah R.; Frey, William H., II; Toth, Cory

    2008-01-01

    Insulin deficiency in type I diabetes may lead to cognitive impairment, cerebral atrophy and white matter abnormalities. We studied the impact of a novel delivery system using intranasal insulin (I-I) in a mouse model of type I diabetes (streptozotocin-induced) for direct targeting of pathological and cognitive deficits while avoiding potential…

  18. Cerebral white matter oxidation and nitrosylation in young rodents with kaolin-induced hydrocephalus.

    PubMed

    Del Bigio, Marc R; Khan, Osaama H; da Silva Lopes, Luiza; Juliet, Packiasamy A R

    2012-04-01

    Hydrocephalus is associated with reduced blood flow in periventricular white matter. To investigate hypoxic and oxidative damage in the brains of rats with hydrocephalus, kaolin was injected into the cisterna magna of newborn 7- and 21-day-old Sprague-Dawley rats, and ventricle size was assessed by magnetic resonance imaging at 7, 21, and 42 days of age. In-situ evidence of hypoxia in periventricular capillaries and glial cells was shown by pimonidazole hydrochloride binding. Biochemical assay of thiobarbituric acid reaction and immunohistochemical detection of malondialdehyde and 4-hydroxy-2-nonenal indicated the presence of lipid peroxidation in white matter. Biochemical assay of nitrite indicated increased nitric oxide production. Nitrotyrosine immunohistochemistry showed nitrosylated proteins in white matter reactive microglia and astrocytes. Activities of the antioxidant enzymes catalase and glutathione peroxidase were not increased, and altered hypoxia-inducible factor 1α was not detected by quantitative reverse transcription-polymerase chain reaction. Cerebral vascular endothelial growth factor expression determined by quantitative reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay was not changed, but vascular endothelial growth factor immunoreactivity was increased in reactive astrocytes of hydrocephalic white matter. To determine if nitric oxide synthase is involved in the pathogenesis, we induced hydrocephalus in 7-day-old wild-type and neuronal nitric oxide synthase-deficient mice. At 7 days, the wild-type and mutant mice exhibited equally severe ventriculomegaly and no behavioral differences, although increased glial fibrillary acidic protein was less in the mutant mice. We conclude that hypoxia, via peroxidation and nitrosylation, contributes to brain changes in young rodents with hydrocephalus and that compensatory mechanisms are negligible.

  19. Cerebral blood flow velocity and cranial fluid volume decrease during +Gz acceleration

    NASA Technical Reports Server (NTRS)

    Kawai, Y.; Puma, S. C.; Hargens, A. R.; Murthy, G.; Warkander, D.; Lundgren, C. E.

    1997-01-01

    Cerebral blood flow (CBF) velocity and cranial fluid volume, which is defined as the total volume of intra- and extracranial fluid, were measured using transcranial Doppler ultrasonography and rheoencephalography, respectively, in humans during graded increase of +Gz acceleration (onset rate: 0.1 G/s) without straining maneuvers. Gz acceleration was terminated when subjects' vision decreased to an angle of less than or equal to 60 degrees, which was defined as the physiological end point. In five subjects, mean CBF velocity decreased 48% from a baseline value of 59.4 +/- 11.2 cm/s to 31.0 +/- 5.6 cm/s (p<0.01) with initial loss of peripheral vision at 5.7 +/- 0.9 Gz. On the other hand, systolic CBF velocity did not change significantly during increasing +Gz acceleration. Cranial impedance, which is proportional to loss of cranial fluid volume, increased by 2.0 +/- 0.8% above the baseline value at the physiological end point (p<0.05). Both the decrease of CBF velocity and the increase of cranial impedance correlated significantly with Gz. These results suggest that +Gz acceleration without straining maneuvers decreases CBF velocity to half normal and probably causes a caudal fluid shift from both intra- and extracranial tissues.

  20. Cerebral White Matter Lesions and Affective Episodes Correlate in Male Individuals with Bipolar Disorder

    PubMed Central

    Birner, Armin; Seiler, Stephan; Lackner, Nina; Bengesser, Susanne A.; Queissner, Robert; Fellendorf, Frederike T.; Platzer, Martina; Ropele, Stefan; Enzinger, Christian; Schwingenschuh, Petra; Mangge, Harald; Pirpamer, Lukas; Deutschmann, Hannes; McIntyre, Roger S.; Kapfhammer, Hans-Peter; Reininghaus, Bernd; Reininghaus, Eva Z.

    2015-01-01

    Background Cerebral white matter lesions (WML) have been found in normal aging, vascular disease and several neuropsychiatric conditions. Correlations of WML with clinical parameters in BD have been described, but not with the number of affective episodes, illness duration, age of onset and Body Mass Index in a well characterized group of euthymic bipolar adults. Herein, we aimed to evaluate the associations between bipolar course of illness parameters and WML measured with volumetric analysis. Methods In a cross-sectional study 100 euthymic individuals with BD as well as 54 healthy controls (HC) were enrolled to undergo brain magnetic resonance imaging using 3T including a FLAIR sequence for volumetric assessment of WML-load using FSL-software. Additionally, clinical characteristics and psychometric measures including Structured Clinical Interview according to DSM-IV, Hamilton-Depression, Young Mania Rating Scale and Beck’s Depression Inventory were evaluated. Results Individuals with BD had significantly more (F = 3.968, p < .05) WML (Mdn = 3710mm3; IQR = 2961mm3) than HC (Mdn = 2185mm3; IQR = 1665mm3). BD men (Mdn = 4095mm3; IQR = 3295mm3) and BD women (Mdn = 3032mm3; IQR = 2816mm3) did not significantly differ as to the WML-load or the number and type of risk factors for WML. However, in men only, the number of manic/hypomanic episodes (r = 0.72; p < .001) as well as depressive episodes (r = 0.51; p < .001) correlated positively with WML-load. Conclusions WML-load strongly correlated with the number of manic episodes in male BD patients, suggesting that men might be more vulnerable to mania in the context of cerebral white matter changes. PMID:26252714

  1. Total cerebral blood flow, white matter lesions and brain atrophy: the SMART-MR study.

    PubMed

    Appelman, Auke P A; van der Graaf, Yolanda; Vincken, Koen L; Tiehuis, Audrey M; Witkamp, Theo D; Mali, Willem P T M; Geerlings, Mirjam I

    2008-03-01

    We investigated whether total cerebral blood flow (CBF) was associated with brain atrophy, and whether this relation was modified by white matter lesions (WML). Within the Second Manifestations of ARTerial disease-magnetic resonance (SMART-MR) study, a prospective cohort study among patients with arterial disease, cross-sectional analyses were performed in 828 patients (mean age 58+/-10 years, 81% male) with quantitative flow, atrophy, and WML measurements on magnetic resonance imaging (MRI). Total CBF was measured with MR angiography and was expressed per 100 mL brain volume. Total brain volume and ventricular volume were divided by intracranial volume to obtain brain parenchymal fraction (BPF) and ventricular fraction (VF). Lower BPF indicates more global brain atrophy, whereas higher VF indicates more subcortical brain atrophy. Mean CBF was 52.0+/-10.2 mL/min per 100 mL, mean BPF was 79.2+/-2.9%, and mean VF was 2.03+/-0.96%. Linear regression analyses showed that lower CBF was associated with more subcortical brain atrophy, after adjusting for age, sex, vascular risk factors, intima-media thickness, and lacunar infarcts, but only in patients with moderate to severe WML (upper quartile of WML): Change in VF per s.d. decrease in CBF 0.18%, 95% CI: 0.02 to 0.34%. Our findings suggest that cerebral hypoperfusion in the presence of WML may be associated with subcortical brain atrophy.

  2. Differential distribution of neurons in the gyral white matter of the human cerebral cortex.

    PubMed

    García-Marín, V; Blazquez-Llorca, L; Rodriguez, J R; Gonzalez-Soriano, J; DeFelipe, J

    2010-12-01

    The neurons in the cortical white matter (WM neurons) originate from the first set of postmitotic neurons that migrates from the ventricular zone. In particular, they arise in the subplate that contains the earliest cells generated in the telencephalon, prior to the appearance of neurons in gray matter cortical layers. These cortical WM neurons are very numerous during development, when they are thought to participate in transient synaptic networks, although many of these cells later die, and relatively few cells survive as WM neurons in the adult. We used light and electron microscopy to analyze the distribution and density of WM neurons in various areas of the adult human cerebral cortex. Furthermore, we examined the perisomatic innervation of these neurons and estimated the density of synapses in the white matter. Finally, we examined the distribution and neurochemical nature of interneurons that putatively innervate the somata of WM neurons. From the data obtained, we can draw three main conclusions: first, the density of WM neurons varies depending on the cortical areas; second, calretinin-immunoreactive neurons represent the major subpopulation of GABAergic WM neurons; and, third, the somata of WM neurons are surrounded by both glutamatergic and GABAergic axon terminals, although only symmetric axosomatic synapses were found. By contrast, both symmetric and asymmetric axodendritic synapses were observed in the neuropil. We discuss the possible functional implications of these findings in terms of cortical circuits.

  3. Morphometric analysis of arteriolar tortuosity in human cerebral white matter of preterm, young, and aged subjects.

    PubMed

    Thore, Clara R; Anstrom, John A; Moody, Dixon M; Challa, Venkata R; Marion, Miranda C; Brown, William R

    2007-05-01

    Arteriolar tortuousities, consisting of vascular coils, loops, and spirals, appear in white matter in a subset of human cerebral vessels. Computerized morphometry was used to analyze brain sections from a broad age range of subjects to determine whether tortuosity is a phenomenon of aging or is associated with leukoaraiosis (LA) or Alzheimer disease (AD). Autopsy brains were studied from 55 subjects ranging in age from 23 weeks postconception to 102 years. Fourteen aged subjects were diagnosed with LA and 7 with AD. By using computerized morphometry, vascular curl (curvilinear length/straight length) was measured in white matter arterioles in 100-microm-thick, alkaline phosphatase-stained sections. Aging subjects, compared with young subjects, showed significant increases in both the prevalence and severity of tortuosity. Curl scores in aged subjects with LA or AD were not significantly different from aged controls without LA or AD. We conclude that 1) tortuous vessels are extremely rare in preterm babies, children, or young adults; 2) significant tortuosity, as indicated by elevated curl scores, begins in middle age; 3) tortuosity does not appear in a subset of aged individuals regardless of longevity; and 4) tortuosity does not appear in a subset of individuals with either LA or AD.

  4. White-collar sign as a predictor of outcome after endovascular treatment for cerebral aneurysms.

    PubMed

    Fukuda, Kenji; Higashi, Toshio; Okawa, Masakazu; Iwaasa, Mitsutoshi; Yoshioka, Tsutomu; Inoue, Tooru

    2017-03-01

    OBJECTIVE The white-collar sign (WCS) is known as a thick neointimal tissue formation at the aneurysm neck after endovascular coil embolization of cerebral aneurysms, which may prevent aneurysm recanalization. The purpose of this study was to evaluate factors involved in the appearance of WCS and to identify radiological and clinical outcomes of treated aneurysms with WCS. METHODS The study included 140 patients with 149 aneurysms in which it was possible to confirm the aneurysm neck between the aneurysm sac and parent artery by using conventional angiography. The WCS was defined as a radiolucent band at the aneurysm neck on the angiogram at 6 months after initial embolization. The radiological outcome was evaluated using MR angiography. RESULTS In 23 of 149 aneurysms (15.4%), a WCS appeared. The WCS-positive group had a significantly smaller neck size (3.3 ± 0.8 mm vs 4.2 ± 1.1 mm, p < 0.001) and smaller aneurysm size (4.3 ± 0.9 mm vs 6.0 ± 2.1 mm, p < 0.001) than the WCS-negative group. Multivariate analysis revealed that WCS appearance was associated with small neck size (OR 0.376, 95% CI 0.179-0.787; p = 0.009). In 106 of 149 aneurysms, the rate of complete occlusion was significantly higher in the WCS-positive group (18/18, 100%) than in the WCS-negative group (n = 54/88, 61.4%; p = 0.001) in the mean follow-up period of 31.0 ± 9.7 months (range 5-52 months). Neither major recanalization nor rupture of the aneurysm occurred in the WCS-positive group. CONCLUSIONS Appearance of the WCS was associated with complete occlusion and good clinical outcome after endovascular coil embolization. The WCS would help to determine the prognosis of cerebral aneurysms after endovascular treatment.

  5. Cerebral white matter hyperintensity in African Americans and European Americans with type 2 diabetes.

    PubMed

    Divers, Jasmin; Hugenschmidt, Christina; Sink, Kaycee M; Williamson, Jeffrey D; Ge, Yaorong; Smith, S Carrie; Bowden, Donald W; Whitlow, Christopher T; Lyders, Eric; Maldjian, Joseph A; Freedman, Barry I

    2013-10-01

    Previous studies involving inner city populations detected higher cerebral white matter hyperintensity (WMH) scores in African Americans (AAs) compared with European Americans (EAs). This finding might be attributable to the higher prevalence of cardiovascular disease (CVD) risk factors and poorer access to healthcare in AAs. Despite racial differences in CVD risk factor profiles, AAs have paradoxically lower levels of subclinical CVD. We hypothesized that AAs with diabetes and good access to healthcare would have comparable or lower levels of WMH as EAs. Racial differences in the distribution of WMH were analyzed in 46 AAs and 156 EAs with type 2 diabetes enrolled in the Diabetes Heart Study (DHS)-Mind, and replicated in a sample of 113 AAs and 61 EAs patients who had clinically indicated cerebral magnetic resonance imaging. Wilcoxon 2-sample tests and linear models were used to compare the distribution of WMH in AAs and EAs and to test for association between WMH and race. The unadjusted mean WMH score from the Diabetes Heart Study-Mind was 1.9 in AAs and 2.3 in EAs (P = .3244). Among those with clinically indicated magnetic resonance imaging, the mean WMH score was 2.9 in AAs and 3.9 in EAs (P = .0503). Adjustment for age and sex produced no statistically significant differences in WMH score between AAs and EAs. These independent datasets reveal comparable WMH scores in AAs and EAs, suggesting that disparities in access to healthcare and environmental exposures likely underlie the previously reported excess burden of WMH in AAs.

  6. Genome-wide meta-analysis of cerebral white matter hyperintensities in patients with stroke

    PubMed Central

    Zhang, Cathy R.; Adib-Samii, Poneh; Devan, William J.; Parsons, Owen E.; Lanfranconi, Silvia; Gregory, Sarah; Cloonan, Lisa; Falcone, Guido J.; Radmanesh, Farid; Fitzpatrick, Kaitlin; Kanakis, Allison; Barrick, Thomas R.; Moynihan, Barry; Lewis, Cathryn M.; Boncoraglio, Giorgio B.; Lemmens, Robin; Thijs, Vincent; Sudlow, Cathie; Wardlaw, Joanna; Rothwell, Peter M.; Meschia, James F.; Worrall, Bradford B.; Levi, Christopher; Bevan, Steve; Furie, Karen L.; Dichgans, Martin; Rosand, Jonathan; Markus, Hugh S.; Rost, Natalia

    2016-01-01

    Objective: For 3,670 stroke patients from the United Kingdom, United States, Australia, Belgium, and Italy, we performed a genome-wide meta-analysis of white matter hyperintensity volumes (WMHV) on data imputed to the 1000 Genomes reference dataset to provide insights into disease mechanisms. Methods: We first sought to identify genetic associations with white matter hyperintensities in a stroke population, and then examined whether genetic loci previously linked to WMHV in community populations are also associated in stroke patients. Having established that genetic associations are shared between the 2 populations, we performed a meta-analysis testing which associations with WMHV in stroke-free populations are associated overall when combined with stroke populations. Results: There were no associations at genome-wide significance with WMHV in stroke patients. All previously reported genome-wide significant associations with WMHV in community populations shared direction of effect in stroke patients. In a meta-analysis of the genome-wide significant and suggestive loci (p < 5 × 10−6) from community populations (15 single nucleotide polymorphisms in total) and from stroke patients, 6 independent loci were associated with WMHV in both populations. Four of these are novel associations at the genome-wide level (rs72934505 [NBEAL1], p = 2.2 × 10−8; rs941898 [EVL], p = 4.0 × 10−8; rs962888 [C1QL1], p = 1.1 × 10−8; rs9515201 [COL4A2], p = 6.9 × 10−9). Conclusions: Genetic associations with WMHV are shared in otherwise healthy individuals and patients with stroke, indicating common genetic susceptibility in cerebral small vessel disease. PMID:26674333

  7. DTI Study of Cerebral Normal-Appearing White Matter in Hereditary Neuropathy With Liability to Pressure Palsies (HNPP)

    PubMed Central

    Wang, Wei-wei; Song, Chun-li; Huang, Liang; Song, Qing-wei; Liang, Zhan-hua; Wei, Qiang; Hu, Jia-ni; Miao, Yan-wei; Wu, Bing; Xie, Lizhi

    2015-01-01

    Abstract The majority of previous studies on hereditary neuropathy with liability to pressure palsies (HNPP) were focused on peripheral nerves, whereas cerebral alterations in HNPP have been less attended to. In this work, Diffusion tensor imaging (DTI) was used to detect the changes in WM, especially in the normal-appearing white matter (NAWM) in HNPP patients for its sensitivity in probing the microstructure of WM, the sensitive metric was searched for probing cerebral alterations and the regional distribution of cerebral abnormalities was identified. Twelve HNPP patients and 12 age- and gender-matched healthy controls underwent the conventional MRI, DTI scan, and electrophysiological examination. The conventional MRI images were first analyzed to identify abnormal intense regions and the NAWM regions. NAWM refers to the white matter regions that do not include the lesions on conventional MRI. The apparent diffusion coefficient and fractional anisotropy (FA) values of the NAWM were then measured and compared between patient and control groups. The sensitivity and specificity of 3 methods and the cerebral regional distribution of MR signal abnormalities were further analyzed. Hyperintense foci were observed on T2 weighted image and fluid attenuated inversion recovery images in 6 patients. Compared to the controls, FA values of the patients were significantly lower in bilateral frontal, orbitofrontal, and temporal NAWMs; whereas the electrophysiological examination results of patients and controls exhibited no statistically significant difference. The sensitivity of FA value was higher than that of electrophysiological examination and conventional MRI. The majority of abnormal signals on conventional MRI images and abnormal FA values were located in the frontal and temporal lobes. The results of our study show cerebral WM changes in HNPP patients. FA value in DTI has been shown to be sensitive to the cerebral microstructural changes in HNPP. The frontal lobe is the

  8. DTI Study of Cerebral Normal-Appearing White Matter in Hereditary Neuropathy With Liability to Pressure Palsies (HNPP).

    PubMed

    Wang, Wei-Wei; Song, Chun-Li; Huang, Liang; Song, Qing-Wei; Liang, Zhan-Hua; Wei, Qiang; Hu, Jia-Ni; Miao, Yan-Wei; Wu, Bing; Xie, Lizhi

    2015-10-01

    The majority of previous studies on hereditary neuropathy with liability to pressure palsies (HNPP) were focused on peripheral nerves, whereas cerebral alterations in HNPP have been less attended to. In this work, Diffusion tensor imaging (DTI) was used to detect the changes in WM, especially in the normal-appearing white matter (NAWM) in HNPP patients for its sensitivity in probing the microstructure of WM, the sensitive metric was searched for probing cerebral alterations and the regional distribution of cerebral abnormalities was identified. Twelve HNPP patients and 12 age- and gender-matched healthy controls underwent the conventional MRI, DTI scan, and electrophysiological examination. The conventional MRI images were first analyzed to identify abnormal intense regions and the NAWM regions. NAWM refers to the white matter regions that do not include the lesions on conventional MRI. The apparent diffusion coefficient and fractional anisotropy (FA) values of the NAWM were then measured and compared between patient and control groups. The sensitivity and specificity of 3 methods and the cerebral regional distribution of MR signal abnormalities were further analyzed. Hyperintense foci were observed on T2 weighted image and fluid attenuated inversion recovery images in 6 patients. Compared to the controls, FA values of the patients were significantly lower in bilateral frontal, orbitofrontal, and temporal NAWMs; whereas the electrophysiological examination results of patients and controls exhibited no statistically significant difference. The sensitivity of FA value was higher than that of electrophysiological examination and conventional MRI. The majority of abnormal signals on conventional MRI images and abnormal FA values were located in the frontal and temporal lobes. The results of our study show cerebral WM changes in HNPP patients. FA value in DTI has been shown to be sensitive to the cerebral microstructural changes in HNPP. The frontal lobe is the

  9. APOL1 renal-risk variants associate with reduced cerebral white matter lesion volume and increased gray matter volume.

    PubMed

    Freedman, Barry I; Gadegbeku, Crystal A; Bryan, R Nick; Palmer, Nicholette D; Hicks, Pamela J; Ma, Lijun; Rocco, Michael V; Smith, S Carrie; Xu, Jianzhao; Whitlow, Christopher T; Wagner, Benjamin C; Langefeld, Carl D; Hawfield, Amret T; Bates, Jeffrey T; Lerner, Alan J; Raj, Dominic S; Sadaghiani, Mohammad S; Toto, Robert D; Wright, Jackson T; Bowden, Donald W; Williamson, Jeff D; Sink, Kaycee M; Maldjian, Joseph A; Pajewski, Nicholas M; Divers, Jasmin

    2016-08-01

    To assess apolipoprotein L1 gene (APOL1) renal-risk-variant effects on the brain, magnetic resonance imaging (MRI)-based cerebral volumes and cognitive function were assessed in 517 African American-Diabetes Heart Study (AA-DHS) Memory IN Diabetes (MIND) and 2568 hypertensive African American Systolic Blood Pressure Intervention Trial (SPRINT) participants without diabetes. Within these cohorts, 483 and 197 had cerebral MRI, respectively. AA-DHS participants were characterized as follows: 60.9% female, mean age of 58.6 years, diabetes duration 13.1 years, estimated glomerular filtration rate of 88.2 ml/min/1.73 m(2), and a median spot urine albumin to creatinine ratio of 10.0 mg/g. In additive genetic models adjusting for age, sex, ancestry, scanner, intracranial volume, body mass index, hemoglobin A1c, statins, nephropathy, smoking, hypertension, and cardiovascular disease, APOL1 renal-risk-variants were positively associated with gray matter volume (β = 3.4 × 10(-3)) and negatively associated with white matter lesion volume (β = -0.303) (an indicator of cerebral small vessel disease) and cerebrospinal fluid volume (β= -30707) (all significant), but not with white matter volume or cognitive function. Significant associations corresponding to adjusted effect sizes (β/SE) were observed with gray matter volume (0.16) and white matter lesion volume (-0.208), but not with cerebrospinal fluid volume (-0.251). Meta-analysis results with SPRINT Memory and Cognition in Decreased Hypertension (MIND) participants who had cerebral MRI were confirmatory. Thus, APOL1 renal-risk-variants are associated with larger gray matter volume and lower white matter lesion volume suggesting lower intracranial small vessel disease.

  10. Cilostazol reduces blood brain barrier dysfunction, white matter lesion formation and motor deficits following chronic cerebral hypoperfusion.

    PubMed

    Edrissi, Hamidreza; Schock, Sarah C; Cadonic, Robert; Hakim, Antoine M; Thompson, Charlie S

    2016-09-01

    Cerebral small vessel disease (CSVD) is a pathological process leading to lacunar infarcts, leukoaraiosis and cerebral microbleeds. Dysfunction of the blood brain barrier (BBB) has been proposed as a mechanism in the progression cerebral small vessel disease. A rodent model commonly used to study some aspects of CSVD is bilateral common carotid artery occlusion (BCCAO) in the rat. In the present study it was determined that gait impairment, as determined by a tapered beam test, and BBB permeability increased following BCCAO. Cilostazol, a type III phosphodiesterase inhibitor, has been shown to have anti-apoptotic effects and prevent white matter vacuolation and rarefaction induced by BCCAO in rats. In this study the protective effect of cilostazol administration on the increase BBB permeability following BCCAO was determined as well as the effect on plasma levels of circulating microparticles (MPs), cerebral white matter rarefaction, glial activation and gait disturbance. The effect of cilostazol on in vitro endothelial barriers was also evaluated. Cilostazol treatment improved BBB permeability and reduced gait disturbance, visual impairment and microglial activation in optic tract following BCCAO in vivo. It also reduced the degree of cell death and the reduction in trans-endothelial electrical resistance (TEER) in artificial endothelial barriers in vitro induced by MP treatment of in vitro barriers.

  11. Diffusion imaging of cerebral white matter in persons who stutter: evidence for network-level anomalies

    PubMed Central

    Cai, Shanqing; Tourville, Jason A.; Beal, Deryk S.; Perkell, Joseph S.; Guenther, Frank H.; Ghosh, Satrajit S.

    2013-01-01

    Deficits in brain white matter have been a main focus of recent neuroimaging studies on stuttering. However, no prior study has examined brain connectivity on the global level of the cerebral cortex in persons who stutter (PWS). In the current study, we analyzed the results from probabilistic tractography between regions comprising the cortical speech network. An anatomical parcellation scheme was used to define 28 speech production-related ROIs in each hemisphere. We used network-based statistic (NBS) and graph theory to analyze the connectivity patterns obtained from tractography. At the network-level, the probabilistic corticocortical connectivity from the PWS group were significantly weaker than that from persons with fluent speech (PFS). NBS analysis revealed significant components in the bilateral speech networks with negative correlations with stuttering severity. To facilitate comparison with previous studies, we also performed tract-based spatial statistics (TBSS) and regional fractional anisotropy (FA) averaging. Results from tractography, TBSS and regional FA averaging jointly highlight the importance of several regions in the left peri-Rolandic sensorimotor and premotor areas, most notably the left ventral premotor cortex (vPMC) and middle primary motor cortex, in the neuroanatomical basis of stuttering. PMID:24611042

  12. Prenatal ischemia deteriorates white matter, brain organization, and function: implications for prematurity and cerebral palsy.

    PubMed

    Coq, Jacques-Olivier; Delcour, Maxime; Massicotte, Vicky S; Baud, Olivier; Barbe, Mary F

    2016-03-01

    Cerebral palsy (CP) describes a group of neurodevelopmental disorders of posture and movement that are frequently associated with sensory, behavioral, and cognitive impairments. The clinical picture of CP has changed with improved neonatal care over the past few decades, resulting in higher survival rates of infants born very preterm. Children born preterm seem particularly vulnerable to perinatal hypoxia-ischemia insults at birth. Animal models of CP are crucial for elucidating underlying mechanisms and for development of strategies of neuroprotection and remediation. Most animal models of CP are based on hypoxia-ischemia around the time of birth. In this review, we focus on alterations of brain organization and functions, especially sensorimotor changes, induced by prenatal ischemia in rodents and rabbits, and relate these alterations to neurodevelopmental disorders found in preterm children. We also discuss recent literature that addresses the relationship between neural and myelin plasticity, as well as possible contributions of white matter injury to the emergence of brain dysfunctions induced by prenatal ischemia.

  13. Plasma tPA-Activity and Progression of Cerebral White Matter Hyperintensities in Lacunar Stroke Patients

    PubMed Central

    van Overbeek, Ellen C.; Staals, Julie; Knottnerus, Iris L. H.; ten Cate, Hugo; van Oostenbrugge, Robert J.

    2016-01-01

    Introduction Tissue plasminogen activator (tPA)-activity and plasminogen activator inhibitor type 1 (PAI-1) antigen are considered to be haemostasis-related markers of endothelial activation and relate to presence of cerebral white matter hyperintensities (WMH) as was earlier shown in a cross-sectional study. We investigated whether tPA-activity and PAI-1 levels are associated with WMH progression in a longitudinal study. Methods In 127 first-ever lacunar stroke patients in whom baseline brain MRI and plasma levels of tPA-activity and PAI-1-antigen were available, we obtained a 2-year follow-up MRI. We assessed WMH progression by a visual WMH change scale. We determined the relationship between levels of tPA-activity and PAI-1 and WMH progression, by logistic regression analysis. Results Plasma tPA-activity was associated with periventricular WMH progression (OR 2.36, 95% CI 1.01–5.49, with correction for age and sex and baseline presence of WMH), but not with deep or any (periventricular and/or deep) WMH progression. PAI-1 levels were lower in patients with WMH progression, but these results were not significant. Conclusion We found a relationship between plasma tPA-activity and progression of periventricular WMH. More research is needed to determine whether there is a (direct) role of tPA in the development and progression of WMH. PMID:26942412

  14. Dehydration accelerates reductions in cerebral blood flow during prolonged exercise in the heat without compromising brain metabolism.

    PubMed

    Trangmar, Steven J; Chiesa, Scott T; Llodio, Iñaki; Garcia, Benjamin; Kalsi, Kameljit K; Secher, Niels H; González-Alonso, José

    2015-11-01

    Dehydration hastens the decline in cerebral blood flow (CBF) during incremental exercise, whereas the cerebral metabolic rate for O2 (CMRO2 ) is preserved. It remains unknown whether CMRO2 is also maintained during prolonged exercise in the heat and whether an eventual decline in CBF is coupled to fatigue. Two studies were undertaken. In study 1, 10 male cyclists cycled in the heat for ∼2 h with (control) and without fluid replacement (dehydration) while internal and external carotid artery blood flow and core and blood temperature were obtained. Arterial and internal jugular venous blood samples were assessed with dehydration to evaluate CMRO2 . In study 2, in 8 male subjects, middle cerebral artery blood velocity was measured during prolonged exercise to exhaustion in both dehydrated and euhydrated states. After a rise at the onset of exercise, internal carotid artery flow declined to baseline with progressive dehydration (P < 0.05). However, cerebral metabolism remained stable through enhanced O2 and glucose extraction (P < 0.05). External carotid artery flow increased for 1 h but declined before exhaustion. Fluid ingestion maintained cerebral and extracranial perfusion throughout nonfatiguing exercise. During exhaustive exercise, however, euhydration delayed but did not prevent the decline in cerebral perfusion. In conclusion, during prolonged exercise in the heat, dehydration accelerates the decline in CBF without affecting CMRO2 and also restricts extracranial perfusion. Thus, fatigue is related to a reduction in CBF and extracranial perfusion rather than CMRO2 .

  15. A case of pathology-proven neuromyelitis optica spectrum disorder with Sjögren syndrome manifesting aphasia and apraxia due to a localized cerebral white matter lesion.

    PubMed

    Sawada, Jun; Orimoto, Ryosuke; Misu, Tatsuro; Katayama, Takayuki; Aizawa, Hitoshi; Asanome, Asuka; Takahashi, Kae; Saito, Tsukasa; Anei, Ryogo; Kamada, Kyousuke; Miyokawa, Naoyuki; Takahashi, Toshiyuki; Fujihara, Kazuo; Hasebe, Naoyuki

    2014-09-01

    A woman with Sjögren syndrome manifesting as aphasia with a left deep cerebral white matter lesion tested positive for anti-aquaporin 4 (AQP4) antibody. Open biopsy of the lesion revealed active demyelination with edematous changes and the preservation of most axons, indicating a non-necrotic demyelinating lesion. Immunostaining for AQP4 was diffusely lost, whereas the loss of glial fibrillary acidic protein immunostaining was limited but with highly degenerated astrocytic foot processes in perivascular areas. These results suggested neuromyelitis optica spectrum disorder (NMOSD) pathology rather than Sjögren-related vasculitis. Only cerebral cortical symptoms with a cerebral white matter lesion could be observed in NMOSDs.

  16. Regional cerebral blood flow, white matter abnormalities, and cerebrospinal fluid hydrodynamics in patients with idiopathic adult hydrocephalus syndrome.

    PubMed

    Kristensen, B; Malm, J; Fagerland, M; Hietala, S O; Johansson, B; Ekstedt, J; Karlsson, T

    1996-03-01

    OBJECTIVES--(1) to evaluate regional cerebral blood flow (rCBF) with single photon emission computed tomography and 99mTc-hexamethylpropyleneamine oxime in patients with the idiopathic adult hydrocephalus syndrome (IAHS); (2) to examine regional cerebral blood flow (rCBF), gait, and psychometric functions before and after CSF removal (CSF tap test); (3) to assess abnormalities in subcortical white matter by MRI. METHODS--Thirty one patients fulfilling the criteria for IAHS (according to history and clinical and neuroradiological examination) were studied. Quantified gait measurements, psychometric testing, and rCBF before and after removal of CSF were obtained. Pressure of CSF and CSF outflow conductance were investigated with a constant pressure infusion method. Brain MRI was used to quantify the severity of white matter lesions and periventricular hyperintensities. In IAHS a widespread rCBF hypoperfusion pattern was depicted, with a caudal frontal and temporal grey matter and subcortical white matter reduction of rCBF as the dominant feature. Removal of CSF was not accompanied by a concomitant increase in rCBF. Significant white matter lesions were detected only in a minority of patients by MRI. An altered CSF hydrodynamic state with a higher CSF pressure and lower conductance was confirmed. IAHS is characterised by an abnormal CSF hydrodynamic state, associated with a widespread rCBF reduction with preference for subcortical white matter and frontal-temporal cortical regions. Furthermore in most patients MRI did not show white matter changes suggestive of a coexistent subcortical arteriosclerotic encephalopathy. At least in the idiopathic group of patients with AHS, measurements of rCBF before and after temporary relief of the CSF hydrodynamic disturbance will not provide additional information that would be helpful in the preoperative evaluation but is suggestive of a preserved autoregulation of rCBF.

  17. Regional cerebral blood flow, white matter abnormalities, and cerebrospinal fluid hydrodynamics in patients with idiopathic adult hydrocephalus syndrome.

    PubMed Central

    Kristensen, B; Malm, J; Fagerland, M; Hietala, S O; Johansson, B; Ekstedt, J; Karlsson, T

    1996-01-01

    OBJECTIVES--(1) to evaluate regional cerebral blood flow (rCBF) with single photon emission computed tomography and 99mTc-hexamethylpropyleneamine oxime in patients with the idiopathic adult hydrocephalus syndrome (IAHS); (2) to examine regional cerebral blood flow (rCBF), gait, and psychometric functions before and after CSF removal (CSF tap test); (3) to assess abnormalities in subcortical white matter by MRI. METHODS--Thirty one patients fulfilling the criteria for IAHS (according to history and clinical and neuroradiological examination) were studied. Quantified gait measurements, psychometric testing, and rCBF before and after removal of CSF were obtained. Pressure of CSF and CSF outflow conductance were investigated with a constant pressure infusion method. Brain MRI was used to quantify the severity of white matter lesions and periventricular hyperintensities. In IAHS a widespread rCBF hypoperfusion pattern was depicted, with a caudal frontal and temporal grey matter and subcortical white matter reduction of rCBF as the dominant feature. Removal of CSF was not accompanied by a concomitant increase in rCBF. Significant white matter lesions were detected only in a minority of patients by MRI. An altered CSF hydrodynamic state with a higher CSF pressure and lower conductance was confirmed. IAHS is characterised by an abnormal CSF hydrodynamic state, associated with a widespread rCBF reduction with preference for subcortical white matter and frontal-temporal cortical regions. Furthermore in most patients MRI did not show white matter changes suggestive of a coexistent subcortical arteriosclerotic encephalopathy. At least in the idiopathic group of patients with AHS, measurements of rCBF before and after temporary relief of the CSF hydrodynamic disturbance will not provide additional information that would be helpful in the preoperative evaluation but is suggestive of a preserved autoregulation of rCBF. PMID:8609504

  18. High blood pressure and cerebral white matter lesion progression in the general population.

    PubMed

    Verhaaren, Benjamin F J; Vernooij, Meike W; de Boer, Renske; Hofman, Albert; Niessen, Wiro J; van der Lugt, Aad; Ikram, M Arfan

    2013-06-01

    High blood pressure is considered an important risk factor for cerebral white matter lesions (WMLs) in the aging population. In a longitudinal population-based study of 665 nondemented persons, we investigated the longitudinal relationship of systolic blood pressure, diastolic blood pressure, and pulse pressure with annual progression of WMLs. Means of blood pressure were calculated over a 5-year period before longitudinal MRI scanning. WML progression was subsequently measured on 2 scans 3.5 years apart. We performed analyses with linear regression models and evaluated adjustments for age, sex, cardiovascular risk factors, and baseline WML volume. In addition, we evaluated whether treatment of hypertension is related to less WML progression. Both systolic and diastolic blood pressures were significantly associated with annual WML progression (regression coefficient [95% confidence interval], 0.08 [0.03; 0.14] mL/y and 0.09 [0.03; 0.15] mL/y per SD increase in systolic and diastolic blood pressure, respectively). Pulse pressure was also significantly associated with WML progression, but not independent from hypertension. After adjustment for baseline WML volume, only systolic blood pressure remained significantly associated: 0.05 (0.00; 0.09) mL/y per SD increase. People with uncontrolled untreated hypertension had significantly more WML progression than people with uncontrolled treated hypertension (difference [95% confidence interval], 0.12 [0.00; 0.23] mL/y). The present study further establishes high blood pressure to precede WMLs and implies that hypertension treatment could reduce WML progression in the general population.

  19. IN VIVO STUDY OF CEREBRAL WHITE MATTER IN THE DOG USING DIFFUSION TENSOR TRACTOGRAPHY

    PubMed Central

    Anaya García, Mitzi Sarahí; Hernández Anaya, Jael Sarahí; Marrufo Meléndez, Oscar; Velázquez Ramírez, José Luis; Palacios Aguiar, Ricardo

    2015-01-01

    Conventional magnetic resonance imaging (MRI) allows investigators and clinicians to observe the anatomy and injuries of the cerebral white matter (CWM) in dogs. However, dynamic images based on the diffusion tensor (DT) technique are required to assess fiber tract integrity of the CWM. Diffusion tensor tractography (DTT) produces a three-dimensional representation in which data are displayed on a colored map obtained from the anisotropy of water molecules in the CWM tracts. Fractional anisotropy (FA) is a value that measures changes in water diffusion, which can occur if the CWM tracts are displaced, disrupted, or infiltrated. The goal of this study was to determine the feasibility of DTT for in vivo examination of the normal appearance of CWM in dogs through visual and quantitative analysis of the most representative CWM tracts. Nine tractographies were performed on healthy dogs using a 3T MRI scanner. T1- and T2-weighted images and DTI were acquired at different planes. Using DTT, three-dimensional reconstructions were obtained. Fractional ansisotropy and apparent diffusion coefficient (ADC) values of the right and left corticospinal tracts, corpus callosum, cingulum, and right and left fronto-occipital fasciculus were determined. Tract reconstructions were similar in 8/9 healthy dogs. Values for FA and ADC were similar in all the dogs. In one dog, tract reconstructions were inhomogeneous; these were displaced because it had larger lateral ventricles. Findings indicated that DTT is a feasible technique for in vivo study of CWM in dogs and that it complements information from conventional MRI. PMID:25288360

  20. Association of cerebral white matter lesions with cognitive function and mood in Japanese elderly people: a population-based study

    PubMed Central

    Yamawaki, Mika; Wada-Isoe, Kenji; Yamamoto, Mikie; Nakashita, Satoko; Uemura, Yusuke; Takahashi, Yoshimitsu; Nakayama, Takeo; Nakashima, Kenji

    2015-01-01

    Background To determine the relationships between regional white matter lesions (WMLs), lifestyle factors, and cognitive, motor function and mood. Methods A comprehensive evaluation, including brain MRI, blood tests, the Unified Parkinson's Disease Rating Scale, the Mini Mental State Examination, and the Geriatric Depression Scale, was performed for people aged 65 years or older living in Ama-cho on October 1, 2009. Participants were classified by severity of periventricular hyperintensities (PVH) and deep white matter hyperintensities (DWMH) using the Fazekas score. Results Of 900 eligible participants, 688 (76.4%) were enrolled, including 303 men. Significant predictors of severe PVH were older age, lower low-density lipoprotein cholesterol (LDL-C) levels, elevated blood pressure (BP), cerebral infarction, and no current alcohol use. Significant predictors of severe DWMH were older age, lower 1,5-anhydroglucitol (1,5-AG) levels, elevated BP, cerebral infarction, and no current alcohol use. Higher cognitive function was associated with younger age, female sex, mild DWMH, more years of education, and higher high-density lipoprotein cholesterol levels. Depressive symptoms were associated with lower 1,5-AG levels, lower LDL-C levels, moderate to severe PVH, and no current alcohol use. Conclusions White matter lesions in elderly people were related to hypertension and impaired glucose tolerance. The severity of WMLs was associated with cognitive function and mood. PMID:25798332

  1. Adenosine A1-Receptors Modulate mTOR Signaling to Regulate White Matter Inflammatory Lesions Induced by Chronic Cerebral Hypoperfusion.

    PubMed

    Cheng, Pengfei; Zuo, Xuzheng; Ren, Yifei; Bai, Shunjie; Tang, Weiju; Chen, Xiuying; Wang, Gong; Wang, Haoxiang; Huang, Wen; Xie, Peng

    2016-12-01

    We sought to investigate the role of the adenosine A1 receptors (A1ARs) in white matter lesions under chronic cerebral hypoperfusion (CCH) and explore the potential repair mechanisms by activation of the receptors. A right unilateral common carotid artery occlusion (rUCCAO) method was used to construct a CCH model. 2-chloro-N6-cyclopentyladenosine (CCPA), a specific agonist of A1ARs, was used to explore the biological mechanisms of repair in white matter lesions under CCH. The expression of mammalian target of rapamycin (mTOR), phosphorylation of mTOR (P-mTOR), myelin basic protein (MBP, a marker of white matter myelination) were detected by Western-blot. Pro-inflammatory cytokine tumor necrosis factor-α (TNF-α) and anti-inflammatory cytokine interleukin-10 (IL-10) levels were determined by ELISA. Compared with the control groups on week 2, 4 and 6, in CCPA-treated groups, the ratio of P-mTOR/mTOR, expression of MBP and IL-10 increased markedly, while the expression of TNF-α reduced at week 6. In conclusion, A1ARs appears to reduce inflammation in white matter via the mTOR signaling pathway in the rUCCAO mice. Therefore, A1ARs may serve as a therapeutic target during the repair of white matter lesions under CCH.

  2. Acceleration of ventricular rate by amiodarone in atrial fibrillation associated with the Wolff-Parkinson-White syndrome

    PubMed Central

    Sheinman, Bryan D; Evans, Tom

    1982-01-01

    Amiodarone has proved to be a valuable drug in atrial fibrillation associated with the Wolff-Parkinson-White syndrome. When it was administered to a patient with this syndrome in atrial fibrillation, who had previously suffered an inferior myocardial infarction, the ventricular rate accelerated from 170 to 230 beats/minute. This unusual case emphasises the need for full electrophysiological assessment of patients with the Wolff-Parkinson-White syndrome for whom amiodarone treatment is being considered. Imagesp1000-a PMID:6812745

  3. GPU-based acceleration of an automatic white matter segmentation algorithm using CUDA.

    PubMed

    Labra, Nicole; Figueroa, Miguel; Guevara, Pamela; Duclap, Delphine; Hoeunou, Josselin; Poupon, Cyril; Mangin, Jean-Francois

    2013-01-01

    This paper presents a parallel implementation of an algorithm for automatic segmentation of white matter fibers from tractography data. We execute the algorithm in parallel using a high-end video card with a Graphics Processing Unit (GPU) as a computation accelerator, using the CUDA language. By exploiting the parallelism and the properties of the memory hierarchy available on the GPU, we obtain a speedup in execution time of 33.6 with respect to an optimized sequential version of the algorithm written in C, and of 240 with respect to the original Python/C++ implementation. The execution time is reduced from more than two hours to only 35 seconds for a subject dataset of 800,000 fibers, thus enabling applications that use interactive segmentation and visualization of small to medium-sized tractography datasets.

  4. Particle acceleration and radio emission for SGRs/AXPs as white dwarf pulsars

    NASA Astrophysics Data System (ADS)

    Lobato, R. V.; Coelho, Jaziel; Malheiro, M.

    2015-07-01

    Recently, an alternative model based on white dwarfs pulsars has been proposed to explain a class of pulsars known as Soft Gamma Repeaters (SGR) and Anomalus X-Ray Pulsars (AXP) [6][4], usually named as magnetars. In this model the magnetized white dwarfs can have surface magnetic field B ∼ 107 — 1010G and rotate very fast with frequencies ω ∼ 1 rad/s, allowing them to produce large electromagnetic (EM) potentials and generate electron-positron pairs. These EM potentials are comparable with the ones of neutron stars pulsars with strong magnetic fields. In our study we consider two possible processes associated with the particle acceleration: in one we have the pair production near to the star polar caps i.e., inside the light cylinder where magnetic-field lines are closed, on the other the creation of pair is in the Outer Magnetosphere i.e., far away of the star surface where magnetic field are open [1]. This analysis of the possibility of radio emission was done for all the 23 SGRs/AXPs of the McGill Online Magnetar Catalog [7] that contains the current information available on these sources. Our work is a first attempted to find an explanation for the puzzle why for all the SGRs/AXPs was expected radio emission, but it was observed in only four of them.

  5. Immediate remote ischemic postconditioning after hypoxia ischemia in piglets protects cerebral white matter but not grey matter

    PubMed Central

    Ezzati, Mojgan; Bainbridge, Alan; Broad, Kevin D; Kawano, Go; Oliver-Taylor, Aaron; Rocha-Ferreira, Eridan; Alonso-Alconada, Daniel; Fierens, Igor; Rostami, Jamshid; Jane Hassell, K; Tachtsidis, Ilias; Gressens, Pierre; Hristova, Mariya; Bennett, Kate; Lebon, Sophie; Fleiss, Bobbi; Yellon, Derek; Hausenloy, Derek J; Golay, Xavier

    2015-01-01

    Remote ischemic postconditioning (RIPostC) is a promising therapeutic intervention whereby brief episodes of ischemia/reperfusion of one organ (limb) mitigate damage in another organ (brain) that has experienced severe hypoxia-ischemia. Our aim was to assess whether RIPostC is protective following cerebral hypoxia-ischemia in a piglet model of neonatal encephalopathy (NE) using magnetic resonance spectroscopy (MRS) biomarkers and immunohistochemistry. After hypoxia-ischemia (HI), 16 Large White female newborn piglets were randomized to: (i) no intervention (n = 8); (ii) RIPostC – with four, 10-min cycles of bilateral lower limb ischemia/reperfusion immediately after HI (n = 8). RIPostC reduced the hypoxic-ischemic-induced increase in white matter proton MRS lactate/N acetyl aspartate (p = 0.005) and increased whole brain phosphorus-31 MRS ATP (p = 0.039) over the 48 h after HI. Cell death was reduced with RIPostC in the periventricular white matter (p = 0.03), internal capsule (p = 0.002) and corpus callosum (p = 0.021); there was reduced microglial activation in corpus callosum (p = 0.001) and more surviving oligodendrocytes in corpus callosum (p = 0.029) and periventricular white matter (p = 0.001). Changes in gene expression were detected in the white matter at 48 h, including KATP channel and endothelin A receptor. Immediate RIPostC is a potentially safe and promising brain protective therapy for babies with NE with protection in white but not grey matter. PMID:26661194

  6. Early alterations in functional connectivity and white matter structure in a transgenic mouse model of cerebral amyloidosis.

    PubMed

    Grandjean, Joanes; Schroeter, Aileen; He, Pan; Tanadini, Matteo; Keist, Ruth; Krstic, Dimitrije; Konietzko, Uwe; Klohs, Jan; Nitsch, Roger M; Rudin, Markus

    2014-10-08

    Impairment of brain functional connectivity (FC) is thought to be an early event occurring in diseases with cerebral amyloidosis, such as Alzheimer's disease. Regions sustaining altered functional networks have been shown to colocalize with regions marked with amyloid plaques burden suggesting a strong link between FC and amyloidosis. Whether the decline in FC precedes amyloid plaque deposition or is a consequence thereof is currently unknown. The sequence of events during early stages of the disease is difficult to capture in humans due to the difficulties in providing an early diagnosis and also in view of the heterogeneity among patients. Transgenic mouse lines overexpressing amyloid precursor proteins develop cerebral amyloidosis and constitute an attractive model system for studying the relationship between plaque and functional changes. In this study, ArcAβ transgenic and wild-type mice were imaged using resting-state fMRI methods across their life-span in a cross-sectional design to analyze changes in FC in relation to the pathology. Transgenic mice show compromised development of FC during the first months of postnatal life compared with wild-type animals, resulting in functional impairments that affect in particular the sensory-motor cortex already in preplaque stage. These functional alterations were accompanied by structural changes as reflected by reduced fractional anisotropy values, as derived from diffusion tensor imaging. Our results suggest cerebral amyloidosis in mice is preceded by impairment of neuronal networks and white matter structures. FC analysis in mice is an attractive tool for studying the implications of impaired neuronal networks in models of cerebral amyloid pathology.

  7. Hypoxia during pregnancy in rats leads to the changes of the cerebral white matter in adult offspring

    SciTech Connect

    Wang, Lingxing; Cai, Ruowei; Lv, Guorong; Huang, Ziyang; Wang, Zhenhua

    2010-05-28

    The aim of the present study is to evaluate the effect of reduced fetal oxygen supply on cerebral white matter in the adult offspring and further assess its susceptibility to postnatal hypoxia and high-fat diet. Based on a 3 x 2 full factorial design consisting of three factors of maternal hypoxia, postnatal high-fat diet, and postnatal hypoxia, the ultrastructure of myelin, axon and capillaries were observed, and the expression of myelin basic protein (MBP), neurofilament-H+L(NF-H+L), and glial fibrillary acidic protein (GFAP) was analyzed in periventricular white matter of 16-month-old offspring. Demyelination, injured axon and damaged microvasculars were observed in maternal hypoxia offspring. The main effect of maternal hypoxia lead to decreased expression of MBP or NF-H+L, and increased expression of GFAP (all P < 0.05). Moreover, there was positive three-way interaction among maternal hypoxia, high-fat diet and postnatal hypoxia on MBP, NF-H+L or GFAP expression (all P < 0.05). In summary, our results indicated that maternal hypoxia during pregnancy in rats lead to changes of periventricular white matter in adult offspring, including demyelination, damaged axon and proliferated astroglia. This effect was amplified by high-fat diet and postnatal hypoxia.

  8. Microglial cells from psychologically stressed mice as an accelerator of cerebral cryptococcosis.

    PubMed

    Shimoda, Masae; Jones, Vickie C; Kobayashi, Makiko; Suzuki, Fujio

    2006-12-01

    Severe stress decreases the resistance of hosts exposed to microbial infections. As compared with two groups of control mice (normal mice, food-and-water-deprived mice [FWD mice]), restraint-stressed mice (RST mice) were shown to be greatly susceptible to intracerebral growth of Cryptococcus neoformans. The susceptibility of FWD mice to cerebral cryptococcosis increased to the level shown in RST mice, when these groups of mice were inoculated with microglial cells from the brains of RST mice. However, the susceptibility of FWD mice to cerebral cryptococcosis was not influenced by the adoptive transfer of microglial cells from normal mice or FWD mice. Microglial cells from RST mice produced CC-chemokine ligand-2 (CCL-2/monocyte chemoattractant protein 1), but not microglial cells from FWD mice. The resistance of RST mice to cerebral cryptococcosis was improved to the extent shown in FWD mice, when they were treated with anti-CCL-2 antibody. However, the susceptibility of normal mice and FWD mice to cerebral cryptococcosis increased to that shown in RST mice, when they were treated with rCCL-2. Microglial cells from RST mice were discriminated from the same cell preparations derived from FWD mice by their abilities to produce CCL-2, to phagocytize C. neoformans cells and to express Toll-like receptor 2. These results indicate that the resistance of RST mice to cerebral cryptococcosis is diminished by CCL-2 produced by microglial cells that are influenced by restraint stress.

  9. Vestibular loss and balance training cause similar changes in human cerebral white matter fractional anisotropy.

    PubMed

    Hummel, Nadine; Hüfner, Katharina; Stephan, Thomas; Linn, Jennifer; Kremmyda, Olympia; Brandt, Thomas; Flanagin, Virginia L

    2014-01-01

    Patients with bilateral vestibular loss suffer from severe balance deficits during normal everyday movements. Ballet dancers, figure skaters, or slackliners, in contrast, are extraordinarily well trained in maintaining balance for the extreme balance situations that they are exposed to. Both training and disease can lead to changes in the diffusion properties of white matter that are related to skill level or disease progression respectively. In this study, we used diffusion tensor imaging (DTI) to compare white matter diffusivity between these two study groups and their age- and sex-matched controls. We found that vestibular patients and balance-trained subjects show a reduction of fractional anisotropy in similar white matter tracts, due to a relative increase in radial diffusivity (perpendicular to the main diffusion direction). Reduced fractional anisotropy was not only found in sensory and motor areas, but in a widespread network including long-range connections, limbic and association pathways. The reduced fractional anisotropy did not correlate with any cognitive, disease-related or skill-related factors. The similarity in FA between the two study groups, together with the absence of a relationship between skill or disease factors and white matter changes, suggests a common mechanism for these white matter differences. We propose that both study groups must exert increased effort to meet their respective usual balance requirements. Since balance training has been shown to effectively reduce the symptoms of vestibular failure, the changes in white matter shown here may represent a neuronal mechanism for rehabilitation.

  10. Radiation-Induced Changes in Normal-Appearing White Matter in Patients With Cerebral Tumors: A Diffusion Tensor Imaging Study

    SciTech Connect

    Nagesh, Vijaya Tsien, Christina I.; Chenevert, Thomas L.; Ross, Brian D.; Lawrence, Theodore S.; Junick, Larry; Cao Yue

    2008-03-15

    Purpose: To quantify the radiation-induced changes in normal-appearing white matter before, during, and after radiotherapy (RT) in cerebral tumor patients. Methods and Materials: Twenty-five patients with low-grade glioma, high-grade glioma, or benign tumor treated with RT were studied using diffusion tensor magnetic resonance imaging. The biologically corrected doses ranged from 50 to 81 Gy. The temporal changes were assessed before, during, and to 45 weeks after the start of RT. The mean diffusivity of water (), fractional anisotropy of diffusion, diffusivity perpendicular ({lambda}{sub perpendicular}) and parallel ({lambda}{sub parallel}) to white matter fibers were calculated in normal-appearing genu and splenium of the corpus callosum. Results: In the genu and splenium, fractional anisotropy decreased and , {lambda}{sub parallel}, {lambda}{sub -perpendicular} increased linearly and significantly with time (p < 0.01). At 45 weeks after the start of RT, {lambda}{sub -perpendicular} had increased {approx}30% in the genu and splenium, and {lambda}{sub parallel} had increased 5% in the genu and 9% in the splenium, suggesting that demyelination is predominant. The increases in {lambda}{sub perpendicular} and {lambda}{sub parallel} were dose dependent, starting at 3 weeks and continuing to 32 weeks from the start of RT. The dose-dependent increase in {lambda}{sub perpendicular} and {lambda}{sub parallel} was not sustained after 32 weeks, indicating the transition from focal to diffuse effects. Conclusion: The acute and subacute changes in normal-appearing white matter fibers indicate radiation-induced demyelination and mild structural degradation of axonal fibers. The structural changes after RT are progressive, with early dose-dependent demyelination and subsequent diffuse dose-independent demyelination and mild axonal degradation. Diffusion tensor magnetic resonance imaging is potentially a biomarker for the assessment of radiation-induced white matter injury.

  11. SU-E-J-143: Short- and Near-Term Effects of Proton Therapy On Cerebral White Matter

    SciTech Connect

    Uh, J; Merchant, T; Ogg, R; Sabin, N; Hua, C; Indelicato, D

    2014-06-01

    Purpose: To assess early effects of proton therapy on the structural integrity of cerebral white matter in relation to the subsequent near-term development of such effects. Methods: Sixteen children (aged 2–19 years) with craniopharyngioma underwent proton therapy of 54 Cobalt Gray Equivalent (CGE) in a prospective therapeutic trial. Diffusion tensor imaging (DTI) was performed at baseline before proton therapy and every 3 months thereafter. Tract-based spatial statics analysis of DTI data was performed to derive the fractional anisotropy (FA) and radial diffusivity (RD) in 26 volumes of interest (VOIs). The dose distributions were spatially normalized to identify VOIs prone to high doses. The longitudinal percentage changes of the FA and RD in these VOIs at 3 and 12 months from the baseline were calculated, and their relationships were evaluated. Results: The average dose was highest to the cerebral peduncle (CP), corticospinal tract (CST) in the pons, pontine crossing tract (PCT), anterior/posterior limbs of the internal capsule (ALIC/PLIC), and genu of the corpus callosum (GCC). It ranged from 33.3 GCE (GCC) to 49.7 GCE (CP). A mild but statistically significant (P<0.05) decline of FA was observed 3 months after proton therapy in all VOIs except the PLIC and ranged from −1.7% (ALIC) to −2.8% (PCT). A significant increase of RD was found in the CP (3.5%) and ALIC (2.1%). The average longitudinal change from the baseline was reduced at 12 months for most VOIs. However, the standard deviation increased, indicating that the temporal pattern varied individually. The follow-up measurements at 3 and 12 months correlated for the CP, CST, PCT, and GCC (P < 0.04). Conclusion: DTI data suggest early (3 months) effects of proton therapy on microstructures in the white matter. The subsequent follow-up indicated individual variation of the changes, which was partly implied by the early effects.

  12. Relationship between characteristics on magnetic resonance imaging and motor outcomes in children with cerebral palsy and white matter injury.

    PubMed

    Reid, Susan M; Ditchfield, Michael R; Bracken, Jenny; Reddihough, Dinah S

    2015-01-01

    In a population cohort of children with white matter injury (WMI) and cerebral palsy (CP), we aimed to describe the magnetic resonance imaging (MRI) characteristics, identify key structure-function relationships, and classify the severity of WMI in a clinically relevant way. Stratified on MRI laterality/symmetry, variables indicating the extent and location of cerebral abnormalities for 272 children with CP and WMI on chronic-phase MRI were related to gross motor function and motor topography using univariable and multivariable approaches. We found that symmetrical involvement, severe WM loss in the hemispheres and corpus callosum, and cerebellar involvement were the strongest predictors of poor gross motor function, but the final model explained only a small proportion of the variability. Bilateral, extensive WM loss was more likely to result in quadriplegia, whereas volume loss in the posterior-mid WM more frequently resulted in diplegia. The extent and location of MRI abnormalities differed according to laterality/symmetry; asymmetry was associated with less extensive hemispheric involvement than symmetrical WMI, and unilateral lesions were more focal and located more anteriorly. In summary, laterality/symmetry of WMI, possibly reflecting different pathogenic mechanisms, together with extent of WM loss and cerebellar abnormality predicted gross motor function in CP, but to a limited extent.

  13. Analyses of Disruption of Cerebral White Matter Integrity in Schizophrenia with MR Diffusion Tensor Fiber Tracking Method

    NASA Astrophysics Data System (ADS)

    Yamamoto, Utako; Kobayashi, Tetsuo; Kito, Shinsuke; Koga, Yoshihiko

    We have analyzed cerebral white matter using magnetic resonance diffusion tensor imaging (MR-DTI) to measure the diffusion anisotropy of water molecules. The goal of this study is the quantitative evaluation of schizophrenia. Diffusion tensor images are acquired for patients with schizophrenia and healthy comparison subjects, group-matched for age, sex, and handedness. Fiber tracking is performed on the superior longitudinal fasciculus for the comparison between the patient and comparison groups. We have analysed and compared the cross-sectional area on the starting coronal plane and the mean and standard deviation of the fractional anisotropy and the apparent diffusion coefficient along fibers in the right and left hemispheres. In the right hemisphere, the cross-sectional areas in patient group are significantly smaller than those in the comparison group. Furthermore, in the comparison group, the cross-sectional areas in the right hemisphere are significantly larger than those in the left hemisphere, whereas there is no significant difference in the patient group. These results suggest that we may evaluate the disruption in white matter integrity in schizophrenic patients quantitatively by comparing the cross-sectional area of the superior longitudinal fasciculus in the right and left hemispheres.

  14. Time-to-Surgery and Pre-operative Cerebral Hemodynamics Predict Post-operative White Matter Injury in Neonates with Hypoplastic Left Heart Syndrome

    PubMed Central

    Lynch, Jennifer M.; Buckley, Erin M.; Schwab, Peter J.; McCarthy, Ann L.; Winters, Madeline E.; Busch, David R.; Xiao, Rui; Goff, Donna A.; Nicolson, Susan C.; Montenegro, Lisa M.; Fuller, Stephanie; Gaynor, J. William; Spray, Thomas L.; Yodh, Arjun G.; Naim, Maryam Y.; Licht, Daniel J.

    2014-01-01

    Objective Hypoxic-ischemic white mater brain injury commonly occurs in neonates with hypoplastic left heart syndrome (HLHS). Approximately half of the HLHS survivors exhibit neurobehavioral symptoms believed to be associated with this injury, though the exact timing of the injury is not known. Methods Neonates with HLHS were recruited for pre- and post-operative monitoring of cerebral oxygen saturation (ScO2), cerebral oxygen extraction fraction (OEF), and cerebral blood flow (CBF) using two non-invasive optical-based techniques, namely diffuse optical spectroscopy and diffuse correlation spectroscopy. Anatomical magnetic resonance imaging (MRI) scans were performed prior to and approximately one week after surgery in order to quantify the extent and timing of the acquired white matter injury. Risk factors for developing new or worsened white matter injury were assessed using uni- and multi-variate logistic regression. Results Thirty-seven neonates with HLHS were studied. In a univariate analysis, neonates who developed a large volume of new, or worsened, postoperative white matter injury had a significantly longer time-to-surgery (p=0.0003). In a multivariate model, longer time between birth and surgery (i.e., time-to-surgery), delayed sternal closure, and higher pre-operative CBF were predictors of post-operative white matter injury. Additionally, longer time-to-surgery and higher pre-operative CBF on morning of surgery were correlated with lower ScO2 (p=0.03 and p=0.05) and higher OEF (p=0.05 and p=0.05). Conclusions Longer time-to-surgery is associated with new post-operative white matter injury in otherwise healthy neonates with HLHS. The results suggest that earlier Norwood palliation may decrease the likelihood of acquiring postoperative white matter injury. PMID:25109755

  15. Age-related slowing of memory retrieval: Contributions of perceptual speed and cerebral white matter integrity

    PubMed Central

    Bucur, Barbara; Madden, David J.; Spaniol, Julia; Provenzale, James M.; Cabeza, Roberto; White, Leonard E.; Huettel, Scott A.

    2007-01-01

    Previous research suggests that, in reaction time (RT) measures of episodic memory retrieval, the unique effects of adult age are relatively small compared to the effects aging shares with more elementary abilities such as perceptual speed. Little is known, however, regarding the mechanisms of perceptual speed. We used diffusion tensor imaging (DTI) to test the hypothesis that white matter integrity, as indexed by fractional anisotropy (FA), serves as one mechanism of perceptual slowing in episodic memory retrieval. Results indicated that declines in FA in the pericallosal frontal region and in the genu of the corpus callosum, but not in other regions, mediated the relationship between perceptual speed and episodic retrieval RT. This relation held, though to a different degree, for both hits and correct rejections. These findings suggest that white matter integrity in prefrontal regions is one mechanism underlying the relation between individual differences in perceptual speed and episodic retrieval. PMID:17383774

  16. Cerebral infarction and myocardial fibrosis in a white-handed gibbon (Hylobates lar).

    PubMed

    Borkowski, R; Taylor, T G; Rush, J

    2000-03-01

    A white-handed gibbon (Hylobates lar) lost the use of its right hand. Complete blood count, serum chemistry profile, electrocardiographic findings, blood pressure, and radiographic work-up were normal, but the gibbon died 2 days later. The gibbon was serologically positive for herpes simplex I and Epstein-Barr virus. Necropsy and histopathology showed acute infarction of the right cerebrum and multifocal to coalescing severe myocardial fibrosis.

  17. Intranasal insulin prevents cognitive decline, cerebral atrophy and white matter changes in murine type I diabetic encephalopathy.

    PubMed

    Francis, George J; Martinez, Jose A; Liu, Wei Q; Xu, Kevin; Ayer, Amit; Fine, Jared; Tuor, Ursula I; Glazner, Gordon; Hanson, Leah R; Frey, William H; Toth, Cory

    2008-12-01

    Insulin deficiency in type I diabetes may lead to cognitive impairment, cerebral atrophy and white matter abnormalities. We studied the impact of a novel delivery system using intranasal insulin (I-I) in a mouse model of type I diabetes (streptozotocin-induced) for direct targeting of pathological and cognitive deficits while avoiding potential adverse systemic effects. Daily I-I, subcutaneous insulin (S-I) or placebo in separate cohorts of diabetic and non-diabetic CD1 mice were delivered over 8 months of life. Radio-labelled insulin delivery revealed that I-I delivered more rapid and substantial insulin levels within the cerebrum with less systemic insulin detection when compared with S-I. I-I delivery slowed development of cognitive decline within weekly cognitive/behavioural testing, ameliorated monthly magnetic resonance imaging abnormalities, prevented quantitative morphological abnormalities in cerebrum, improved mouse mortality and reversed diabetes-mediated declines in mRNA and protein for phosphoinositide 3-kinase (PI3K)/Akt and for protein levels of the transcription factors cyclic AMP response element binding protein (CREB) and glycogen synthase kinase 3beta (GSK-3beta) within different cerebral regions. Although the murine diabetic brain was not subject to cellular loss, a diabetes-mediated loss of protein and mRNA for the synaptic elements synaptophysin and choline acetyltransferase was prevented with I-I delivery. As a mechanism of delivery, I-I accesses the brain readily and slows the development of diabetes-induced brain changes as compared to S-I delivery. This therapy and delivery mode, available in humans, may be of clinical utility for the prevention of pathological changes in the diabetic human brain.

  18. Accelerated infarct development, cytogenesis and apoptosis following transient cerebral ischemia in aged rats.

    PubMed

    Popa-Wagner, Aurel; Badan, Irina; Walker, Lary; Groppa, Sergiu; Patrana, Nicoleta; Kessler, Christof

    2007-03-01

    Old age is associated with a deficient recovery from stroke, but the cellular mechanisms underlying such phenomena are poorly understood. To address this issue, focal cerebral ischemia was produced by reversible occlusion of the right middle cerebral artery in 3- and 20-month-old male Sprague-Dawley rats. Aged rats showed a delayed and suboptimal functional recovery in the post-stroke period. Using BrdU-labeling, quantitative immunohistochemistry and 3-D reconstruction of confocal images, we found that aged rats are predisposed to rapidly develop an infarct within the first few days after ischemia. The emergence of the necrotic zone is associated with a high rate of cellular degeneration, premature accumulation of proliferating BrdU-positive cells that appear to emanate from capillaries in the infarcted area, and a large number of apoptotic cells. With double labeling techniques, we were able to identify, for the first time, over 60% of BrdU-positive cells either as reactive microglia (45%), oligodendrocyte progenitors (17%), astrocytes (23%), CD8+ lymphocytes (4%), or apoptotic cells (<1%). Paradoxically, despite a robust reactive phenotype of microglia and astrocytes in aged rats, at 1-week post-stroke, the number of proliferating microglia and astrocytes was lower in aged rats than in young rats. Our data indicate that aging is associated with rapid infarct development and a poor prognosis for full recovery from stroke that is correlated with premature cellular proliferation and increased cellular degeneration and apoptosis in the infarcted area.

  19. Cerebral ischemia or intrauterine inflammation promotes differentiation of oligodendroglial precursors in preterm ovine fetuses: possible cellular basis for white matter injury.

    PubMed

    Kitanishi, Ryuta; Matsuda, Tadashi; Watanabe, Shinpei; Saito, Masatoshi; Hanita, Takushi; Watanabe, Tatsuya; Kobayashi, Yoshiyasu

    2014-01-01

    White matter injury in premature infants is known to be major cause of long-term neurocognitive disability, but the pathogenic mechanism remains unclear, hampering our ability to develop preventions. Periventricular leukomalacia is a severe form of white matter injury. In the present study, we explored the effects of cerebral ischemia and/or intrauterine inflammation on the development of oligodendroglia in the cerebral white matter using chronically instrumented fetal sheep. Each fetus received one of three insults: hemorrhage, inflammation and their combination. In the hemorrhage group, 40% of the fetoplacental blood volume was acutely withdrawn, and 24 hours after removal, the blood was returned to the fetus. The inflammation group received intravenous granulocyte-colony stimulating factor and intra-amniotic endotoxin and thus suffered from necrotizing funisitis and chorioamnionitis. The inflammatory hemorrhage group underwent acute hemorrhage under the inflammatory state. The sham group received no insults. Importantly, periventricular leukomalacia was not detected in the sham and the inflammation groups. Differentiating oligodendroglia at various developmental stages were identified by immunohistochemical analysis with specific antibodies. No difference in the density of oligodendroglial progenitors was detected among the four groups, whereas oligodendroglial precursors were significantly reduced in the three insult groups, compared to sham control. Moreover, the density of immature oligodendroglia was higher in the inflammation group and the inflammatory hemorrhage group, while the density of mature oligodendroglia was highest in the hemorrhage group. We propose that cerebral ischemia or intrauterine inflammation induces the differentiation of oligodendroglial precursors in preterm fetuses, eventually resulting in their exhaustion.

  20. Normal-Appearing Cerebral White Matter in Healthy Adults: Mean Change over Two Years and Individual Differences in Change

    PubMed Central

    Bender, Andrew R.; Raz, Naftali

    2015-01-01

    Diffusion tensor imaging (DTI) studies show age-related differences in cerebral white matter (WM). However, few have studied WM changes over time, and none evaluated individual differences in change across a wide age range. Here, we examined two-year WM change in 96 healthy adults (baseline age 19-78 years), individual differences in change, and the influence of vascular and metabolic risk thereon. Fractional anisotropy (FA), axial diffusivity (AD) and radial diffusivity (RD) represented microstructural properties of normal appearing WM within 13 regions. Cross-sectional analyses revealed age-related differences in all WM indices across the regions. In contrast, latent change score analyses showed longitudinal declines in AD in association and projection fibers, and increases in anterior commissural fibers. FA and RD evidenced a less consistent pattern of change. Metabolic risk mediated the effects of age on FA and RD change in corpus callosum body and dorsal cingulum. These findings underscore the importance of longitudinal studies in evaluating individual differences in change, and the role of metabolic factors in shaping trajectories of brain aging. PMID:25771392

  1. Alterations in Cerebral White Matter and Neuropsychology in Patients with Cirrhosis and Falls

    PubMed Central

    Gómez-Ansón, Beatriz; Román, Eva; Fernández de Bobadilla, Ramón; Pires-Encuentra, Patricia; Díaz-Manera, Jordi; Núñez, Fidel; Martinez-Horta, Saül; Vives-Gilabert, Yolanda; Pagonabarraga, Javier; Kulisevsky, Jaume; Guarner, Carlos; Soriano, Germán

    2015-01-01

    Background & Aim Falls are frequent in patients with cirrhosis but underlying mechanisms are unknown. The aim was to determine the neuropsychological, neurological and brain alterations using magnetic resonance-diffusion tensor imaging (MR-DTI) in cirrhotic patients with falls. Patients and methods Twelve patients with cirrhosis and falls in the previous year were compared to 9 cirrhotic patients without falls. A comprehensive neuropsychological and neurological evaluation of variables that may predispose to falls included: the Mini-Mental State Examination, Psychometric Hepatic Encephalopathy Score (PHES), Parkinson’s Disease-Cognitive Rating Scale, specific tests to explore various cognitive domains, Unified Parkinson’s Disease Rating Scale to evaluate parkinsonism, scales for ataxia and muscular strength, and electroneurography. High-field MR (3T) including DTI and structural sequences was performed in all patients. Results The main neuropsychological findings were impairment in PHES (p = 0.03), Parkinson’s Disease-Cognitive Rating Scale (p = 0.04) and in executive (p<0.05) and visuospatial-visuoconstructive functions (p<0.05) in patients with falls compared to those without. There were no statistical differences between the two groups in the neurological evaluation or in the visual assessment of MRI. MR-DTI showed alterations in white matter integrity in patients with falls compared to those without falls (p<0.05), with local maxima in the superior longitudinal fasciculus and corticospinal tract. These alterations were independent of PHES as a covariate and correlated with executive dysfunction (p<0.05). Conclusions With the limitation of the small sample size, our results suggest that patients with cirrhosis and falls present alterations in brain white matter tracts related to executive dysfunction. These alterations are independent of PHES impairment. PMID:25793766

  2. Increased apoptosis and hypomyelination in cerebral white matter of macular mutant mouse brain.

    PubMed

    Takikita, Shoichi; Takano, Tomoyuki; Narita, Tsutomu; Maruo, Yoshihiro

    2015-09-01

    Hypomyelination in developing brain is often accompanied by congenital metabolic disorders. Menkes kinky hair disease is an X-linked neurodegenerative disease of impaired copper transport, resulting from a mutation of the Menkes disease gene, a transmembrane copper-transporting p-type ATPase gene (ATP7A). In a macular mutant mouse model, the murine ortholog of Menkes gene (mottled gene) is mutated, and widespread neurodegeneration and subsequent death are observed. Although some biochemical analysis of myelin protein in macular mouse has been reported, detailed histological study of myelination in this mouse model is currently lacking. Since myelin abnormality is one of the neuropathologic findings of human Menkes disease, in this study early myelination in macular mouse brain was evaluated by immunohistochemistry. Two-week-old macular mice and normal littermates were perfused with 4% paraformaldehyde. Immunohistochemical staining of paraffin embedded and vibratome sections was performed using antibodies against either CNPase, cleaved caspase-3 or O4 (marker of immature oligodendrocytes). This staining showed that cerebral myelination in macular mouse was generally hypoplastic and that hypomyelination was remarkable in internal capsule, corpus callosum, and cingulate cortex. In addition, an increased number of cleaved caspase-3 positive cells were observed in corpus callosum and internal capsule. Copper deficiency induced by low copper diet has been reported to induce oligodendrocyte dysfunction and leads to hypomyelination in this mouse model. Taken together, hypomyelination observed in this study in a mouse model of Menkes disease is assumed to be induced by increased apoptosis of immature oligodendrocytes in developing cerebrum, through deficient intracellular copper metabolism.

  3. Increased apoptosis and hypomyelination in cerebral white matter of macular mutant mouse brain

    PubMed Central

    Takikita, Shoichi; Takano, Tomoyuki; Narita, Tsutomu; Maruo, Yoshihiro

    2015-01-01

    Hypomyelination in developing brain is often accompanied by congenital metabolic disorders. Menkes kinky hair disease is an X-linked neurodegenerative disease of impaired copper transport, resulting from a mutation of the Menkes disease gene, a transmembrane copper-transporting p-type ATPase gene (ATP7A). In a macular mutant mouse model, the murine ortholog of Menkes gene (mottled gene) is mutated, and widespread neurodegeneration and subsequent death are observed. Although some biochemical analysis of myelin protein in macular mouse has been reported, detailed histological study of myelination in this mouse model is currently lacking. Since myelin abnormality is one of the neuropathologic findings of human Menkes disease, in this study early myelination in macular mouse brain was evaluated by immunohistochemistry. Two-week-old macular mice and normal littermates were perfused with 4% paraformaldehyde. Immunohistochemical staining of paraffin embedded and vibratome sections was performed using antibodies against either CNPase, cleaved caspase-3 or O4 (marker of immature oligodendrocytes). This staining showed that cerebral myelination in macular mouse was generally hypoplastic and that hypomyelination was remarkable in internal capsule, corpus callosum, and cingulate cortex. In addition, an increased number of cleaved caspase-3 positive cells were observed in corpus callosum and internal capsule. Copper deficiency induced by low copper diet has been reported to induce oligodendrocyte dysfunction and leads to hypomyelination in this mouse model. Taken together, hypomyelination observed in this study in a mouse model of Menkes disease is assumed to be induced by increased apoptosis of immature oligodendrocytes in developing cerebrum, through deficient intracellular copper metabolism. PMID:26937406

  4. Characterization of Cerebral White Matter Properties Using Quantitative Magnetic Resonance Imaging Stains

    PubMed Central

    Hurley, Samuel A.; Samsonov, Alexey A.; Adluru, Nagesh; Hosseinbor, Ameer Pasha; Mossahebi, Pouria; Tromp, Do P.M.; Zakszewski, Elizabeth; Field, Aaron S.

    2011-01-01

    Abstract The image contrast in magnetic resonance imaging (MRI) is highly sensitive to several mechanisms that are modulated by the properties of the tissue environment. The degree and type of contrast weighting may be viewed as image filters that accentuate specific tissue properties. Maps of quantitative measures of these mechanisms, akin to microstructural/environmental-specific tissue stains, may be generated to characterize the MRI and physiological properties of biological tissues. In this article, three quantitative MRI (qMRI) methods for characterizing white matter (WM) microstructural properties are reviewed. All of these measures measure complementary aspects of how water interacts with the tissue environment. Diffusion MRI, including diffusion tensor imaging, characterizes the diffusion of water in the tissues and is sensitive to the microstructural density, spacing, and orientational organization of tissue membranes, including myelin. Magnetization transfer imaging characterizes the amount and degree of magnetization exchange between free water and macromolecules like proteins found in the myelin bilayers. Relaxometry measures the MRI relaxation constants T1 and T2, which in WM have a component associated with the water trapped in the myelin bilayers. The conduction of signals between distant brain regions occurs primarily through myelinated WM tracts; thus, these methods are potential indicators of pathology and structural connectivity in the brain. This article provides an overview of the qMRI stain mechanisms, acquisition and analysis strategies, and applications for these qMRI stains. PMID:22432902

  5. Cerebral white matter lesions – associations with Aβ isoforms and amyloid PET

    PubMed Central

    van Westen, Danielle; Lindqvist, Daniel; Blennow, Kaj; Minthon, Lennart; Nägga, Katarina; Stomrud, Erik; Zetterberg, Henrik; Hansson, Oskar

    2016-01-01

    Small vessel disease (SVD) and amyloid deposition may promote each other, with a potential association between SVD and altered production or clearance of β-amyloid (Aβ) affecting its cleavage products. We investigated the relationship between SVD, multiple isoforms of Aβ in cerebrospinal fluid (CSF) and cortical Aβ in 831 subjects with cognitive performance ranging from normal to Alzheimer’s disease (AD) (the Swedish BioFINDER study). SVD was estimated as white matter lesions (WML) and lacunes. 18F-flutemetamol PET was performed in 321 subjects. Lower CSF levels of Aβ38 and Aβ40 were consistently associated with increased WML in all subgroups, while lower levels of CSF Aβ42 were associated with WML mainly in AD. CSF Aβ38 and Aβ40 were associated with regional WML in all regions, while CSF Aβ42 was associated with temporal WML only. A composite measure of 18F-flutemetamol uptake was not associated with WML, and regional 18F-flutemetamol uptake only with temporal WML. Lacunes were not associated with Aβ isoforms nor 18F-flutemetamol uptake. Our results suggest that WML may be associated with alterations in the production or clearance of Aβ species, particularly of Aβ38 and Aβ40. However, in AD cases, Aβ42 pathology might be associated with WML, especially in the temporal lobe. PMID:26856756

  6. Cardiotonic pill attenuates white matter and hippocampal damage via inhibiting microglial activation and downregulating ERK and p38 MAPK signaling in chronic cerebral hypoperfused rat

    PubMed Central

    2013-01-01

    Background The cardiotonic pill (CP) is a herbal medicine composed of Salvia miltiorrhiza (SM), Panax notoginseng (PN), and Dryobalanops aromatica Gaertner (DAG) that is widely used to treat cardiovascular diseases. The present experiment was conducted to examine the effects of CP on white matter and hippocampal damage induced by chronic cerebral hypoperfusion. Methods Chronic cerebral hypoperfusion was induced in male Wistar rats by permanent bilateral common carotid artery occlusion (BCCAo). Daily oral administration of CP (200 mg/kg) began 21 days after BCCAo and continued for 42 days. The levels of microglial activation and myelin basic protein (MBP) were measured in the white matter and hippocampus of rats with chronic BCCAo, and the expression levels of mitogen-activated protein kinases (MAPKs) and inflammatory markers such as cyclooxygenase-2, interleukin-1β, and interleukin-6 were examined. Results MBP expression was reduced in the white matter and hippocampal regions of rats that received BCCAo. In contrast, reduced levels of MBP were not observed in BCCAo rats given CP treatments. The administration of CP alleviated microglial activation, the alteration of ERK and p38 MAPK signaling, and inflammatory mediator expression in rats with chronic BCCAo. Conclusion These results suggest that CP may have protective effects against chronic BCCAo-induced white matter and hippocampal damage by inhibiting inflammatory processes including microglial activation and proinflammatory mediator expression, and downreguating the hyperphosphorylation of ERK and p38 MAPK signaling. PMID:24274593

  7. Persistent, Long-term Cerebral White Matter Changes after Sports-Related Repetitive Head Impacts

    PubMed Central

    Bazarian, Jeffrey J.; Zhu, Tong; Zhong, Jianhui; Janigro, Damir; Rozen, Eric; Roberts, Andrew; Javien, Hannah; Merchant-Borna, Kian; Abar, Beau; Blackman, Eric G.

    2014-01-01

    Introduction Repetitive head impacts (RHI) sustained in contact sports are thought to be necessary for the long-term development of chronic traumatic encephalopathy (CTE). Our objectives were to: 1) characterize the magnitude and persistence of RHI-induced white matter (WM) changes; 2) determine their relationship to kinematic measures of RHI; and 3) explore their clinical relevance. Methods Prospective, observational study of 10 Division III college football players and 5 non-athlete controls during the 2011-12 season. All subjects underwent diffusion tensor imaging (DTI), physiologic, cognitive, and balance testing at pre-season (Time 1), post-season (Time 2), and after 6-months of no-contact rest (Time 3). Head impact measures were recorded using helmet-mounted accelerometers. The percentage of whole-brain WM voxels with significant changes in fractional anisotropy (FA) and mean diffusivity (MD) from Time 1 to 2, and Time 1 to 3 was determined for each subject and correlated to head impacts and clinical measures. Results Total head impacts for the season ranged from 431–1,850. No athlete suffered a clinically evident concussion. Compared to controls, athletes experienced greater changes in FA and MD from Time 1 to 2 as well as Time 1 to 3; most differences at Time 2 persisted to Time 3. Among athletes, the percentage of voxels with decreased FA from Time 1 to 2 was positively correlated with several helmet impact measures. The persistence of WM changes from Time 1 to 3 was also associated with changes in serum ApoA1 and S100B autoantibodies. WM changes were not consistently associated with cognition or balance. Conclusions A single football season of RHIs without clinically-evident concussion resulted in WM changes that correlated with multiple helmet impact measures and persisted following 6 months of no-contact rest. This lack of WM recovery could potentially contribute to cumulative WM changes with subsequent RHI exposures. PMID:24740265

  8. Chronic lead treatment accelerates photochemically induced platelet aggregation in cerebral microvessels of mice, in vivo

    SciTech Connect

    Al Dhaheri, A.H.; El-Sabban, F.; Fahim, M.A.

    1995-04-01

    Effects of two chronic treatment levels with lead on platelet aggregation in cerebral (pial) microcirculation of the mouse were investigated. Exposure to lead was made by subcutaneous injections for 7 days of lead acetate dissolved in 5% glucose solution, vehicle. Two doses of lead were used, a low dose of 0.1 mg/kg and a high dose of 1.0 mg/kg. Adult male mice were divided into three groups, 10 each; one group was injected with vehicle (control), another was injected with the low dose, and the third was injected with the high dose. Additional mice were used for the determination of hematological parameters and for the lead level in serum of the three groups. On the eighth day, platelet aggregation in pial microvessels of these groups of mice was carried out in vivo. Animals were anesthetized (urethane, 1-2 mg/g, ip), the trachea was intubated, and a craniotomy was performed. Platelet aggregation in pial microvessels was induced photochemically, by activation of circulating sodium fluorescein (0.1 mg/25 g, iv) with an intense mercury light. The time required for the first platelet aggregate to appear in pial arterioles was significantly shorter in the lead-treated mice than in control. This effect was in a dose-dependent manner; 113 {+-} 44 sec for low dose and 71 {+-} 18 sec for high dose vs 155 {+-} 25 sec for control, P < 0.02 and P < 0.001, respectively. Between the two lead-treated groups, the high dose significantly (P < 0.05) shortened the time to first aggregate. These data evidenced an increased susceptibility to cerebrovascular thrombosis as a result of exposure to lead. 26 refs., 4 figs., 2 tabs.

  9. Doxycycline treatment in a neonatal rat model of hypoxia-ischemia reduces cerebral tissue and white matter injury: a longitudinal magnetic resonance imaging study.

    PubMed

    Widerøe, Marius; Havnes, Marianne B; Morken, Tora Sund; Skranes, Jon; Goa, Pål-Erik; Brubakk, Ann-Mari

    2012-07-01

    Doxycycline may potentially be a neuroprotective treatment for neonatal hypoxic-ischemic brain injury through its anti-inflammatory effects. The aim of this study was to examine any long-term neuroprotection by doxycycline treatment on cerebral gray and white matter. Hypoxic-ischemic brain injury was induced in 7-day-old rats. Pups were treated with either doxycycline (HI+doxy) or saline (HI+vehicle) by intraperitoneal injection at 1 h after hypoxia-ischemia (HI). At 6 h after HI, MnCl(2) was injected intraperitoneally for later manganese-enhanced magnetic resonance imaging (MRI). MRI was performed with diffusion-weighted imaging on day 1 and T(1) -weighted imaging and diffusion tensor imaging at 7, 21 and 42 days after HI. Animals were killed after MRI on day 42 and histological examinations of the brains were performed. There was a tendency towards lower lesion volumes on diffusion maps among HI+doxy than HI+vehicle rats at 1 day after HI. Volumetric MRI showed increasing differences between groups with time after HI, with less cyst formation and less cerebral tissue loss among HI+doxy than HI+vehicle pups. HI+doxy pups had less manganese enhancement on day 7 after HI, indicating reduced inflammation. HI+doxy pups had higher fractional anisotropy on diffusion tensor imaging in major white matter tracts in the injured hemisphere than HI+vehicle pups, indicating less injury to white matter and better myelination. Histological examinations supported the MRI results. Lesion size on early MRI was highly correlated with final injury measures. In conclusion, a single dose of doxycycline reduced long-term cerebral tissue loss and white matter injury after neonatal HI, with an increasing effect of treatment with time after injury.

  10. Diffuse reduction of white matter connectivity in cerebral palsy with specific vulnerability of long range fiber tracts.

    PubMed

    Englander, Zoë A; Pizoli, Carolyn E; Batrachenko, Anastasiya; Sun, Jessica; Worley, Gordon; Mikati, Mohamad A; Kurtzberg, Joanne; Song, Allen W

    2013-01-01

    Cerebral palsy (CP) is a heterogeneous group of non-progressive motor disorders caused by injury to the developing fetal or infant brain. Although the defining feature of CP is motor impairment, numerous other neurodevelopmental disabilities are associated with CP and contribute greatly to its morbidity. The relationship between brain structure and neurodevelopmental outcomes in CP is complex, and current evidence suggests that motor and developmental outcomes are related to the spatial pattern and extent of brain injury. Given that multiple disabilities are frequently associated with CP, and that there is increasing burden of neurodevelopmental disability with increasing motor severity, global white matter (WM) connectivity was examined in a cohort of 17 children with bilateral CP to test the hypothesis that increased global WM damage will be seen in the group of severely affected (Gross Motor Function Classification Scale (GMFCS) level of IV) as compared to moderately affected (GMFCS of II or III) individuals. Diffusion tensor tractography was performed and the resulting fibers between anatomically defined brain regions were quantified and analyzed in relation to GMFCS levels. Overall, a reduction in total WM connectivity throughout the brain in severe versus moderate CP was observed, including but not limited to regions associated with the sensorimotor system. Our results also show a diffuse and significant reduction in global inter-regional connectivity between severity groups, represented by inter-regional fiber count, throughout the brain. Furthermore, it was also observed that there is a significant difference (p = 0.02) in long-range connectivity in patients with severe CP as compared to those with moderate CP, whereas short-range connectivity was similar between groups. This new finding, which has not been previously reported in the CP literature, demonstrates that CP may involve distributed, network-level structural disruptions.

  11. Structural connectivity of the anterior cingulate in children with unilateral cerebral palsy due to white matter lesions.

    PubMed

    Scheck, Simon M; Pannek, Kerstin; Raffelt, David A; Fiori, Simona; Boyd, Roslyn N; Rose, Stephen E

    2015-01-01

    In this work we investigate the structural connectivity of the anterior cingulate cortex (ACC) and its link with impaired executive function in children with unilateral cerebral palsy (UCP) due to periventricular white matter lesions. Fifty two children with UCP and 17 children with typical development participated in the study, and underwent diffusion and structural MRI. Five brain regions were identified for their high connectivity with the ACC using diffusion MRI fibre tractography: the superior frontal gyrus, medial orbitofrontal cortex, rostral middle frontal gyrus, precuneus and isthmus cingulate. Structural connectivity was assessed in pathways connecting these regions to the ACC using three diffusion MRI derived measures: fractional anisotropy (FA), mean diffusivity (MD) and apparent fibre density (AFD), and compared between participant groups. Furthermore we investigated correlations of these measures with executive function as assessed by the Flanker task. The ACC-precuneus tract had significantly different MD (p < 0.0001) and AFD (p = 0.0072) between groups, with post-hoc analysis showing significantly increased MD in the right hemisphere of children with left hemiparesis compared with controls. The ACC-superior frontal gyrus tract had significantly different FA (p = 0.0049) and MD (p = 0.0031) between groups. AFD in this tract (contralateral to side of hemiparesis; right hemisphere in controls) showed a significant relationship with Flanker task performance (p = 0.0045, β = -0.5856), suggesting that reduced connectivity correlates with executive dysfunction. Reduced structural integrity of ACC tracts appears to be important in UCP, in particular the connection to the superior frontal gyrus. Although damage to this area is heterogeneous it may be important in early identification of children with impaired executive function.

  12. Microfiltration of enzyme treated egg whites for accelerated detection of viable Salmonella.

    PubMed

    Ku, Seockmo; Ximenes, Eduardo; Kreke, Thomas; Foster, Kirk; Deering, Amanda J; Ladisch, Michael R

    2016-11-01

    We report detection of <13 CFU of Salmonella per 25 g egg white within 7 h by concentrating the bacteria using microfiltration through 0.2-μm cutoff polyethersulfone hollow fiber membranes. A combination of enzyme treatment, controlled cross-flow on both sides of the hollow fibers, and media selection were key to controlling membrane fouling so that rapid concentration and the subsequent detection of low numbers of microbial cells were achieved. We leveraged the protective effect of egg white proteins and peptone so that the proteolytic enzymes did not attack the living cells while hydrolyzing the egg white proteins responsible for fouling. The molecular weight of egg white proteins was reduced from about 70 kDa to 15 kDa during hydrolysis. This enabled a 50-fold concentration of the cells when a volume of 525 mL of peptone and egg white, containing 13 CFU of Salmonella, was decreased to a 10 mL volume in 50 min. A 10-min microcentrifugation step further concentrated the viable Salmonella cells by 10×. The final cell recovery exceeded 100%, indicating that microbial growth occurred during the 3-h processing time. The experiments leading to rapid concentration, recovery, and detection provided further insights on the nature of membrane fouling enabling fouling effects to be mitigated. Unlike most membrane processes where protein recovery is the goal, recovery of viable microorganisms for pathogen detection is the key measure of success, with modification of cell-free proteins being both acceptable and required to achieve rapid microfiltration of viable microorganisms. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1464-1471, 2016.

  13. Complications Following Linear Accelerator Based Stereotactic Radiation for Cerebral Arteriovenous Malformations

    SciTech Connect

    Skjoth-Rasmussen, Jane; Roed, Henrik; Ohlhues, Lars; Jespersen, Bo; Juhler, Marianne

    2010-06-01

    Purpose: Primarily, gamma knife centers are predominant in publishing results on arteriovenous malformations (AVM) treatments including reports on risk profile. However, many patients are treated using a linear accelerator-most of these at smaller centers. Because this setting is different from a large gamma knife center, the risk profile at Linac departments could be different from the reported experience. Prescribed radiation doses are dependent on AVM volume. This study details results from a medium sized Linac department center focusing on risk profiles. Method and Materials: A database was searched for all patients with AVMs. We included 50 consecutive patients with a minimum of 24 months follow-up (24-51 months). Results: AVM occlusion was verified in 78% of patients (39/50). AVM occlusion without new deficits (excellent outcome) was obtained in 44%. Good or fair outcome (AVM occlusion with mild or moderate new deficits) was seen in 30%. Severe complications after AVM occlusion occurred in 4% with a median interval of 15 months after treatment (range, 1-26 months). Conclusions: We applied an AVM grading score developed at the Mayo Clinic to predict probable outcome after radiosurgery in a large patient population treated with Gamma knife. A cutoff above and below a score of 1.5 could not discriminate between the likelihood of having an excellent outcome (approximately 45%). The chance of having an excellent or good outcome was slightly higher in patients with an AVM score below 1.5 (64% vs. 57%).

  14. Arterial Spin-Labeled Perfusion Combined with Segmentation Techniques to Evaluate Cerebral Blood Flow in White and Gray Matter of Children with Sickle Cell Anemia

    PubMed Central

    Helton, Kathleen J.; Paydar, Amir; Glass, John; Weirich, Eric M.; Hankins, Jane; Li, Chin-Shang; Smeltzer, Matthew P.; Wang, Winfred C.; Ware, Russell E.; Ogg, Robert J.

    2015-01-01

    Background Changes in cerebral perfusion are an important feature of the pathophysiology of sickle cell anemia (SCA); cerebrovascular ischemia occurs frequently and leads to neurocognitive deficits, silent infarcts, and overt stroke. Non-invasive MRI methods to measure cerebral blood flow (CBF) by arterial spin labeling (ASL) afford new opportunities to characterize disease- and therapy-induced changes in cerebral hemodynamics in patients with SCA. Recent studies have documented elevated gray matter (GM) CBF in untreated children with SCA, but no measurements of white matter (WM) CBF have been reported. Procedures Pulsed ASL with automated brain image segmentation-classification techniques were used to determine the CBF in GM, WM, and abnormal white matter (ABWM) of 21 children with SCA, 18 of whom were receiving hydroxyurea therapy. Results GM and WM CBF were highly associated (R2 =.76, p< 0.0001) and the GM to WM CBF ratio was 1.6 (95% confidence interval: 1.43-1.83). Global GM CBF in our treated cohort was 87 ± 24 mL/min/100 g, a value lower than previously reported in untreated patients with SCA. CBF was elevated in normal appearing WM (43 ± 14 mL/min/100 g) but decreased in ABWM (6 ± 12 mL/min/100 g), compared to published normal pediatric controls. Hemispheric asymmetry in CBF was noted in most patients. Conclusions These perfusion measurements suggest that hydroxyurea may normalize GM CBF in children with SCA, but altered perfusion in WM may persist. This novel combined approach for CBF quantification will facilitate prospective studies of cerebral vasculopathy in SCA, particularly regarding the effects of treatments such as hydroxyurea. PMID:18937311

  15. A Post-stroke Therapeutic Regimen with Omega-3 Polyunsaturated Fatty Acids that Promotes White Matter Integrity and Beneficial Microglial Responses after Cerebral Ischemia.

    PubMed

    Jiang, Xiaoyan; Pu, Hongjian; Hu, Xiaoming; Wei, Zhishuo; Hong, Dandan; Zhang, Wenting; Gao, Yanqin; Chen, Jun; Shi, Yejie

    2016-12-01

    White matter injury induced by ischemic stroke elicits sensorimotor impairments, which can be further deteriorated by persistent proinflammatory responses. We previously reported that delayed and repeated treatments with omega-3 polyunsaturated fatty acids (n-3 PUFAs) improve spatial cognitive functions and hippocampal integrity after ischemic stroke. In the present study, we report a post-stroke n-3 PUFA therapeutic regimen that not only confers protection against neuronal loss in the gray matter but also promotes white matter integrity. Beginning 2 h after 60 min of middle cerebral artery occlusion (MCAO), mice were randomly assigned to receive intraperitoneal docosahexaenoic acid (DHA) injections (10 mg/kg, daily for 14 days), alone or in combination with dietary fish oil (FO) supplements starting 5 days after MCAO. Sensorimotor functions, gray and white matter injury, and microglial responses were examined up to 28 days after MCAO. Our results showed that DHA and FO combined treatment-facilitated long-term sensorimotor recovery and demonstrated greater beneficial effect than DHA injections alone. Mechanistically, n-3 PUFAs not only offered direct protection on white matter components, such as oligodendrocytes, but also potentiated microglial M2 polarization, which may be important for white matter repair. Notably, the improved white matter integrity and increased M2 microglia were strongly linked to the mitigation of sensorimotor deficits after stroke upon n-3 PUFA treatments. Together, our results suggest that post-stroke DHA injections in combination with FO dietary supplement benefit white matter restoration and microglial responses, thereby dictating long-term functional improvements.

  16. Carotid-Femoral Pulse Wave Velocity Is Associated With Cerebral White Matter Lesions in Type 2 Diabetes

    PubMed Central

    Laugesen, Esben; Høyem, Pernille; Stausbøl-Grøn, Brian; Mikkelsen, Anders; Thrysøe, Samuel; Erlandsen, Mogens; Christiansen, Jens S.; Knudsen, Søren T.; Hansen, Klavs W.; Kim, Won Y.; Hansen, Troels K.; Poulsen, Per L.

    2013-01-01

    OBJECTIVE Patients with type 2 diabetes have a high incidence of cardiovascular events including stroke. Increased arterial stiffness (AS) predicts cardiovascular events in the general population. Cerebral white matter lesions (WMLs) are associated with an increased risk of stroke. It is unknown whether AS in patients with type 2 diabetes is associated with WMLs. RESEARCH DESIGN AND METHODS We examined 89 patients recently diagnosed with type 2 diabetes (<5 years) and 89 sex- and age-matched controls. AS was assessed with carotid-femoral pulse wave velocity (PWV). WMLs were identified using magnetic resonance imaging and graded qualitatively with the Breteler scale (no/slight changes = 0, moderate changes = 1, severe changes = 2) and semiquantitatively. RESULTS The diabetic population had excellent glycemic control (HbA1c, 6.5% [6.2–6.8]; median [interquartile range {IQR}]) and had, compared with the controls, lower office blood pressure (BP) (127 ± 12/79 ± 8 vs. 132 ± 14/84 ± 10 mmHg) and total cholesterol (4.3[3.9–4.7] vs. 5.6 [5.1–6.4]; mmol/L; median [IQR]), (P < 0.01 for all). Despite this, PWV was higher in the patients with diabetes compared with controls (9.3 ± 2.0 vs. 8.0 ± 1.6 m/s; P < 0.0001). PWV was associated with Breteler score (OR 1.36 [95% CI 1.17–1.58]; P < 0.001) and WML volume (OR 1.32 [95% CI 1.16–1.51]; P < 0.001) per 1 m/s increase in PWV. These associations remained significant when adjusted for age, sex, diabetes, 24-h mean arterial BP, BMI, heart rate, and use of antihypertensives and statins (Breteler score: OR 1.28 [95% CI 1.03–1.60]; P < 0.05 and WML volume: OR 1.30 [95% CI 1.06–1.58]; P < 0.05). CONCLUSIONS PWV was higher among patients with well-controlled type 2 diabetes compared with controls and was independently associated with WMLs. PWV may represent a clinically relevant parameter in the evaluation of cerebrovascular disease risk in type 2 diabetes. PMID:23129135

  17. Study of white matter at the centrum semiovale level with magnetic resonance spectroscopy and diffusion tensor imaging in cerebral small vessel disease.

    PubMed

    Huang, L A; Ling, X Y; Li, C; Zhang, S J; Chi, G B; Xu, A D

    2014-04-08

    White matter lesion (WML) in magnetic resonance imaging is commonly observed in patients with cerebral small vessel disease (SVD), but the pathological mechanism of WML in SVD is still unclear. We observed the metabolism and microscopic anatomy of white matter in SVD patients. Twelve subjects clinically diagnosed with SVD and 6 normal control subjects were examined with magnetic resonance spectroscopy (MRS) and diffusion tensor imaging (DTI). The white matter at the centrum semiovale level was selected as the region of interest (ROI). The ROI metabolism parameters, including N-acetyl-l-aspartic acid (NAA), creatine (Cr), and choline (Cho) were measured by MRS. Microscopic parameters such as mean diffusion (MD) and fractional anisotropy (FA) in ROI were obtained by DTI. Compared with the normal control group, bilateral MD values in the SVD group were significantly elevated, whereas bilateral FA values in SVD were decreased, but the difference was not statistically significant. Additionally, NAA/Cho, Cho/Cr, and NAA/Cr showed no significant statistical differences. Our study suggests that the mechanisms of the SVD cognitive impairment are related to damage of the white matter structures rather than to brain metabolism.

  18. FGF21 Lowers Plasma Triglycerides by Accelerating Lipoprotein Catabolism in White and Brown Adipose Tissues.

    PubMed

    Schlein, Christian; Talukdar, Saswata; Heine, Markus; Fischer, Alexander W; Krott, Lucia M; Nilsson, Stefan K; Brenner, Martin B; Heeren, Joerg; Scheja, Ludger

    2016-03-08

    FGF21 decreases plasma triglycerides (TGs) in rodents and humans; however, the underlying mechanism or mechanisms are unclear. In the present study, we examined the role of FGF21 in production and disposal of TG-rich lipoproteins (TRLs) in mice. Treatment with pharmacological doses of FGF21 acutely reduced plasma non-esterified fatty acids (NEFAs), liver TG content, and VLDL-TG secretion. In addition, metabolic turnover studies revealed that FGF21 facilitated the catabolism of TRL in white adipose tissue (WAT) and brown adipose tissue (BAT). FGF21-dependent TRL processing was strongly attenuated in CD36-deficient mice and transgenic mice lacking lipoprotein lipase in adipose tissues. Insulin resistance in diet-induced obese and ob/ob mice shifted FGF21 responses from WAT toward energy-combusting BAT. In conclusion, FGF21 lowers plasma TGs through a dual mechanism: first, by reducing NEFA plasma levels and consequently hepatic VLDL lipidation and, second, by increasing CD36 and LPL-dependent TRL disposal in WAT and BAT.

  19. Impact of cerebral white matter changes on functionality in older adults: An overview of the LADIS Study results and future directions.

    PubMed

    Pantoni, Leonardo; Fierini, Fabio; Poggesi, Anna

    2015-12-01

    The evidence on the clinical significance of cerebral white matter changes (WMC) has mounted over the past few decades. WMC are recognized as one of the neuroimaging features of cerebral small vessel disease, and are associated with various disturbances and a poor prognosis. The Leukoaraiosis and Disability (LADIS) Study has contributed substantially to this body of knowledge. LADIS is a European multicenter collaboration aimed at assessing the role of WMC as an independent predictor of the transition to disability in initially non-disabled patients aged 65-84 years. Besides the demonstration that severe WMC cause a more than double risk of transition from an autonomous to a dependent status after 3 years of follow-up, the LADIS Study has also provided evidence on the role of WMC in relation to the decline of cognitive and motor performances, depressive symptoms associated with aging and cerebrovascular diseases, the presence of urinary disturbances, and various neurological abnormalities. The possible role of other lesions (lacunar infarcts, cerebral atrophy, corpus callosum morphology) and microstructural abnormalities (diffusion-weighted imaging changes in normal appearing brain tissue and in WMC) has also been investigated. In the present article, we review the main results of the LADIS Study and offer some considerations for future developments in the field, paying attention to the potential use of WMC progression as a surrogate marker in intervention trials in cerebral small vessel diseases. We also discuss some therapeutic perspectives regarding the beneficial impact of physical activity on the risk of vascular cognitive impairment in patients with WMC.

  20. The ameliorative effects of exercise on cognitive impairment and white matter injury from blood-brain barrier disruption induced by chronic cerebral hypoperfusion in adolescent rats.

    PubMed

    Lee, Jae-Min; Park, Jong-Min; Song, Min Kyung; Oh, Yoo Joung; Kim, Chang-Ju; Kim, Youn-Jung

    2017-01-18

    Vascular dementia is the progressive change in blood vessels that leads to neuronal injuries in vulnerable areas induced by chronic cerebral hypoperfusion (CCH). CCH induces disruption of blood-brain barrier (BBB), and this BBB disruption can initiate the cognitive impairment and white matter injury. In the present study, we evaluated the effect of treadmill exercise on the cognitive impairment, white matter injury, and BBB disruption induced by CCH. Vascular dementia was induced by permanent bilateral common carotid arteries occlusion (BCCAO) in rats. The rats in the exercise group were made to run on a treadmill for 30min once a day for 14 weeks, starting 4 weeks after birth. Our results revealed that treadmill exercise group was alleviated the cognitive impairment and myelin degradation induced by CCH. The disruption of BBB after CCH indicates degradation of occludin, zonula occluden-1 (ZO-1), and up-regulation of matrix metalloproteinases (MMPs). Treadmill exercise may provide protective effects on BBB disruption from degradation of occludin, ZO-1, and overexpression of MMP-9 after CCH. These findings suggest that treadmill exercise ameliorates cognitive impairment and white matter injury from BBB disruption induced by CCH in rats. The present study will be valuable for means of prophylactic and therapeutic intervention for patients with CCH.

  1. Topographic changes in cerebral blood flow and reduced white matter integrity in the first 2 weeks following revascularization surgery in adult moyamoya disease.

    PubMed

    Kazumata, Ken; Tha, Khin Khin; Uchino, Haruto; Shiga, Tohru; Shichinohe, Hideo; Ito, Masaki; Nakayama, Naoki; Abumiya, Takeo

    2016-09-02

    OBJECTIVE After revascularization surgery, hyperperfusion and ischemia are associated with morbidity and mortality in adult moyamoya disease (MMD). However, structural changes within the brain following revascularization surgery, especially in the early postsurgical period, have not been thoroughly studied. Such knowledge may enable improved monitoring and clinical management of hyperperfusion and ischemia in MMD. Thus, the objective of this study was to investigate the topographic and temporal profiles of cerebral perfusion and related white matter microstructural changes following revascularization surgery in adult MMD. METHODS The authors analyzed 20 consecutive surgeries performed in 17 adults. Diffusion imaging in parallel with serial measurements of regional cerebral blood flow (rCBF) using SPECT was performed. Both voxel-based and region-of-interest analyses were performed, comparing neuroimaging parameters of postoperative hemispheres with those of preoperative hemispheres at 4 different time points within 2 weeks after surgery. RESULTS Voxel-based analysis showed a distinct topographic pattern of cerebral perfusion, characterized by increased rCBF in the basal ganglia for the first several days and gradually increased rCBF in the lateral prefrontal cortex over 1 week (p < 0.001). Decreased rCBF was also observed in the lateral prefrontal cortex, occipital lobe, and cerebellum contralateral to the surgical hemisphere (p < 0.001). Reduced fractional anisotropy (FA) and axial diffusivity (AD), as well as increased radial diffusivity (RD), were demonstrated in both the anterior and posterior limbs of the internal capsule (p < 0.001). Diffusion parameters demonstrated the greatest changes in both FA and RD on Days 1-2 and in AD on Days 3-6; FA, RD, and AD recovered to preoperative levels on Day 14. Patients with transient neurological deteriorations (TNDs), as compared with those without, demonstrated greater increases in rCBF in both the lateral prefrontal

  2. The Differential Effect of Arm Movements during Gait on the Forward Acceleration of the Centre of Mass in Children with Cerebral Palsy and Typically Developing Children

    PubMed Central

    Meyns, Pieter; Molenaers, Guy; Duysens, Jacques; Jonkers, Ilse

    2017-01-01

    Background: We aimed to study the contribution of upper limb movements to propulsion during walking in typically developing (TD) children (n = 5) and children with hemiplegic and diplegic cerebral palsy (CP; n = 5 and n = 4, respectively). Methods: Using integrated three-dimensional motion capture data and a scaled generic musculoskeletal model that included upper limbs, we generated torque driven simulations of gait in OpenSim. Induced acceleration analyses were then used to determine the contributions of the individual actuators located at the relevant degrees of freedoms of the upper and lower limb joints to the forward acceleration of the COM at each time point of the gait simulation. The mean values of the contribution of the actuators of upper limbs, lower limbs, and gravity in different phases of the gait cycle were compared between the three groups. Findings: The results indicated a limited contribution of the upper limb actuators to COM forward acceleration compared to the contribution of lower limbs and gravity, in the three groups. In diplegic CP, the contribution of the upper limbs seemed larger compared to TD during the preswing and swing phases of gait. In hemiplegic CP, the unaffected arm seemed to contribute more to COM deceleration during (pre)swing, while the affected side contributed to COM acceleration. Interpretation: These findings suggest that in the presence of lower limb dysfunction, the contribution of the upper limbs to forward propulsion is altered, although they remain negligible compared to the lower limbs and gravity. PMID:28298890

  3. Obstructive Sleep Apnea as a Risk Factor for Cerebral White Matter Change in a Middle-Aged and Older General Population

    PubMed Central

    Kim, Hyun; Yun, Chang-Ho; Thomas, Robert Joseph; Lee, Seung Hoon; Seo, Hyung Suk; Cho, Eo Rin; Lee, Seung Ku; Yoon, Dae Wui; Suh, Sooyeon; Shin, Chol

    2013-01-01

    Study Objective: Obstructive sleep apnea (OSA) contributes to the development of systemic hypertension, and hypertension strongly predicts the development of white matter change (WMC). Thus, it is plausible that OSA mediates WMC. The goal of the current study is to determine whether a contextual relationship exists between OSA and cerebral WMC. Design: Cross-sectional analyses conducted in a population-based study. Setting: Korean community-based sample from the Korean Genome and Epidemiology Study (KoGES) who attended examinations in 2011 at a medical center. Participants: There were 503 individuals (mean ± SD, age 59.63 ± 7.48 y) who were free of previously diagnosed cardiovascular and neurologic diseases. Measurements and Results: Participants underwent 1-night polysomnography and were classified as no OSA (obstructive apnea-hypopnea index [AHI] < 5, n = 289), mild OSA (AHI 5-15, n = 161), and moderate to severe OSA (AHI ≥ 15, n = 53). WMC was identified with brain magnetic resonance imaging (MRI) and was found in 199 individuals (39.56%). Multivariate logistic regression analyses adjusted for covariates revealed that moderate to severe OSA was significantly associated with the presence of WMC (odds ratio [OR] 2.08, 95%, confidence interval [CI] 1.05-4.13) compared with no OSA. Additional adjustment of hypertension to the model did not alter the significance of the association (OR 2.03, 95% CI 1.02-4.05). Conclusions: Moderate to severe OSA is an independent risk factor for WMC in middle-aged and older individuals. Thus, early recognition and treatment of OSA could reduce the risk of stroke and vascular dementia. Citation: Kim H; Yun CH; Thomas RJ; Lee SH; Seo HS; Cho ER; Lee SK; Yoon DW; Suh S; Shin C. Obstructive sleep apnea as a risk factor for cerebral white matter change in a middle-aged and older general population. SLEEP 2013;36(5):709-715. PMID:23633753

  4. The human cerebral cortex is neither one nor many: neuronal distribution reveals two quantitatively different zones in the gray matter, three in the white matter, and explains local variations in cortical folding

    PubMed Central

    Ribeiro, Pedro F. M.; Ventura-Antunes, Lissa; Gabi, Mariana; Mota, Bruno; Grinberg, Lea T.; Farfel, José M.; Ferretti-Rebustini, Renata E. L.; Leite, Renata E. P.; Filho, Wilson J.; Herculano-Houzel, Suzana

    2013-01-01

    The human prefrontal cortex has been considered different in several aspects and relatively enlarged compared to the rest of the cortical areas. Here we determine whether the white and gray matter of the prefrontal portion of the human cerebral cortex have similar or different cellular compositions relative to the rest of the cortical regions by applying the Isotropic Fractionator to analyze the distribution of neurons along the entire anteroposterior axis of the cortex, and its relationship with the degree of gyrification, number of neurons under the cortical surface, and other parameters. The prefrontal region shares with the remainder of the cerebral cortex (except for occipital cortex) the same relationship between cortical volume and number of neurons. In contrast, both occipital and prefrontal areas vary from other cortical areas in their connectivity through the white matter, with a systematic reduction of cortical connectivity through the white matter and an increase of the mean axon caliber along the anteroposterior axis. These two parameters explain local differences in the distribution of neurons underneath the cortical surface. We also show that local variations in cortical folding are neither a function of local numbers of neurons nor of cortical thickness, but correlate with properties of the white matter, and are best explained by the folding of the white matter surface. Our results suggest that the human cerebral cortex is divided in two zones (occipital and non-occipital) that differ in how neurons are distributed across their gray matter volume and in three zones (prefrontal, occipital, and non-occipital) that differ in how neurons are connected through the white matter. Thus, the human prefrontal cortex has the largest fraction of neuronal connectivity through the white matter and the smallest average axonal caliber in the white matter within the cortex, although its neuronal composition fits the pattern found for other, non-occipital areas. PMID

  5. Associations of Sleep Apnea, NRG1 Polymorphisms, Alcohol Consumption, and Cerebral White Matter Hyperintensities: Analysis with Genome-Wide Association Data

    PubMed Central

    Baik, Inkyung; Seo, Hyung Suk; Yoon, Daewui; Kim, Seong Hwan; Shin, Chol

    2015-01-01

    Study Objective: There are few studies on gene-environment interactions with obstructive sleep apnea (OSA). Our study aimed to explore genetic polymorphisms associated with OSA using genome-wide association (GWA) data and evaluate the effects of relevant polymorphisms on the association between risk factors, including obesity and alcohol consumption, and OSA. We also investigated on these associations in relation to cerebral white matter hyperintensities (WMH) on magnetic resonance images. Design: A cross-sectional design. Setting: A polysomnography study embedded in a population-based cohort from the Korean Genome Epidemiology Study was conducted in 2011–2013. Participants: 1,763 participants aged 48–78 years. Results: 251 individuals were identified to have OSA with an apnea-hypopnea index ≥ 15. A common polymorphism of neuregulin-1 gene (NRG1), rs10097555, was selected as the most suggestive locus associated with OSA (P value < 10−5) based on the results of GWA analysis in a matched case-control subsample (n = 470). Among 1,763 participants, we found that the presence of the NRG1 polymorphism is inversely associated with OSA (P value < 0.01) even after taking into account potential risk factors; the multivariate odds ratio (95% confidence interval) for the mutant alleles was 0.57 (0.39–0.82) compared with the wild-type. We observed that this association is modified by alcohol consumption (P < 0.05), not by obesity. We also observed that WMH are positively associated with OSA independent of the NRG1 polymorphism and alcohol consumption (P < 0.05). Conclusions: These findings suggest that the neuregulin-1 gene (NRG1) may be involved in the etiological mechanisms of obstructive sleep apnea (OSA) and that carriers of a particular NRG1 mutation may be less likely to have OSA if they do not drink alcoholic beverages. Citation: Baik I, Seo HS, Yoon D, Kim SH, Shin C. Associations of sleep apnea, NRG1 polymorphisms, alcohol consumption, and cerebral white

  6. ASPREE-NEURO study protocol: A randomized controlled trial to determine the effect of low-dose aspirin on cerebral microbleeds, white matter hyperintensities, cognition, and stroke in the healthy elderly.

    PubMed

    Ward, Stephanie A; Raniga, Parnesh; Ferris, Nicholas J; Woods, Robyn L; Storey, Elsdon; Bailey, Michael J; Brodtmann, Amy; Yates, Paul A; Donnan, Geoffrey A; Trevaks, Ruth E; Wolfe, Rory; Egan, Gary F; McNeil, John J

    2017-01-01

    Rationale Cerebral microbleeds seen on brain magnetic resonance imaging are markers of small vessel disease, linked to cognitive dysfunction and increased ischemic and hemorrhagic stroke risk. Observational studies suggest that aspirin use may induce cerebral microbleeds, and associated overt intracranial hemorrhage, but this has not been definitively resolved. Aims ASPREE-NEURO will determine the effect of aspirin on cerebral microbleed development over three years in healthy adults aged 70 years and over, participating in the larger 'ASPirin in Reducing Events in the Elderly (ASPREE)' primary prevention study of aspirin. Sample size Five hundred and fifty-nine participants provide 75% power (two-sided p value of 0.05) to determine an average difference of 0.5 cerebral microbleed per person after three years. Methods and design A multi-center, randomized placebo-controlled trial of 100 mg daily aspirin in participants who have brain magnetic resonance imaging at study entry, one and three years after randomization and who undergo cognitive testing at the same time points. Study outcomes The primary outcome is the number of new cerebral microbleeds on magnetic resonance imaging after three years. Secondary outcomes are the number of new cerebral microbleeds after one year, change in volume of white matter hyperintensity, cognitive function, and stroke. Discussion ASPREE-NEURO will resolve whether aspirin affects the presence and number of cerebral microbleeds, their relationship with cognitive performance, and indicate whether consideration of cerebral microbleeds alters the risk-benefit profile of aspirin in primary prevention for older people. Trial registration Australian New Zealand Clinical Trials Registry ACTRN12613001313729.

  7. Correlation of fractional anisotropy and metabolite concentrations measured using 1H-MRS of cerebral white matter in healthy adults.

    PubMed

    Cheng, Sainan; Liu, Qiang; Lv, Yubo; Han, Wenwen; Yu, Ke; Li, Yuchao; Gong, Tao; Zhang, Yi

    2014-01-01

    Fractional anisotropy (FA) is currently an ideal index capable of reflecting the white matter structure. 1H magnetic resonance spectroscopy (1H-MRS) is often used as a noninvasive concentration measurement of important neurochemicals in vivo. This study was conducted to investigate the relationship between FA and metabolite concentrations by comparing 1H-MRS of bilateral medium corona radiata in healthy adults. The data of diffusion tensor imaging (DTI) and 1H-MRS were acquired from 31 healthy adults using a 3.0 T MR system. All subjects were divided into three groups: the total group (mean age=42 years), the junior group (mean age=29 years) and the senior group (mean age=56 years). There was a negative correlation between FA and age in three groups (r=-0.146, r=-0.204, r=-0.162, p<0.05). The positive correlation of FA with corresponding concentrations of N-acetylaspartate (NAA) was significant in three groups (r=0.339, r=0.213, r=0.430, respectively, p<0.05). The positive correlation of FA with the corresponding NAA/Cr was only significant difference between the total 353 samples and the junior group (r=0.166, r=0.305, respectively, p<0.05). Combining 1H-MRS with DTI reveals the relationship between structure and metabolic characteristics of white matter.

  8. Abnormal white matter tractography of visual pathways detected by high-angular-resolution diffusion imaging (HARDI) corresponds to visual dysfunction in cortical/cerebral visual impairment.

    PubMed

    Bauer, Corinna M; Heidary, Gena; Koo, Bang-Bon; Killiany, Ronald J; Bex, Peter; Merabet, Lotfi B

    2014-08-01

    Cortical (cerebral) visual impairment (CVI) is characterized by visual dysfunction associated with damage to the optic radiations and/or visual cortex. Typically it results from pre- or perinatal hypoxic damage to postchiasmal visual structures and pathways. The neuroanatomical basis of this condition remains poorly understood, particularly with regard to how the resulting maldevelopment of visual processing pathways relates to observations in the clinical setting. We report our investigation of 2 young adults diagnosed with CVI and visual dysfunction characterized by difficulties related to visually guided attention and visuospatial processing. Using high-angular-resolution diffusion imaging (HARDI), we characterized and compared their individual white matter projections of the extrageniculo-striate visual system with a normal-sighted control. Compared to a sighted control, both CVI cases revealed a striking reduction in association fibers, including the inferior frontal-occipital fasciculus as well as superior and inferior longitudinal fasciculi. This reduction in fibers associated with the major pathways implicated in visual processing may provide a neuroanatomical basis for the visual dysfunctions observed in these patients.

  9. The influence of aerobic fitness on cerebral white matter integrity and cognitive function in older adults: results of a one-year exercise intervention.

    PubMed

    Voss, Michelle W; Heo, Susie; Prakash, Ruchika S; Erickson, Kirk I; Alves, Heloisa; Chaddock, Laura; Szabo, Amanda N; Mailey, Emily L; Wójcicki, Thomas R; White, Siobhan M; Gothe, Neha; McAuley, Edward; Sutton, Bradley P; Kramer, Arthur F

    2013-11-01

    Cerebral white matter (WM) degeneration occurs with increasing age and is associated with declining cognitive function. Research has shown that cardiorespiratory fitness and exercise are effective as protective, even restorative, agents against cognitive and neurobiological impairments in older adults. In this study, we investigated whether the beneficial impact of aerobic fitness would extend to WM integrity in the context of a one-year exercise intervention. Further, we examined the pattern of diffusivity changes to better understand the underlying biological mechanisms. Finally, we assessed whether training-induced changes in WM integrity would be associated with improvements in cognitive performance independent of aerobic fitness gains. Results showed that aerobic fitness training did not affect group-level change in WM integrity, executive function, or short-term memory, but that greater aerobic fitness derived from the walking program was associated with greater change in WM integrity in the frontal and temporal lobes, and greater improvement in short-term memory. Increases in WM integrity, however, were not associated with short-term memory improvement, independent of fitness improvements. Therefore, while not all findings are consistent with previous research, we provide novel evidence for correlated change in training-induced aerobic fitness, WM integrity, and cognition among healthy older adults.

  10. Differential Aging of Cerebral White Matter in Middle-Aged and Older Adults: A Seven-Year Follow-up

    PubMed Central

    Bender, Andrew R.; Völkle, Manuel C.; Raz, Naftali

    2015-01-01

    The few extant reports of longitudinal white matter (WM) changes in healthy aging, using diffusion tensor imaging (DTI), reveal substantial differences in change across brain regions and DTI indices. According to the last-in-first-out hypothesis of brain aging late-developing WM tracts may be particularly vulnerable to advanced age. To test this hypothesis we compared age-related changes in association, commissural and projection WM fiber regions using a skeletonized, region of interest DTI approach. Using linear mixed effects models, we evaluated the influences of age and vascular risk at baseline on seven-year changes in three indices of WM integrity and organization (axial diffusivity, AD, radial diffusivity, RD, and fractional anisotropy, FA) in healthy middle-aged and older adults (mean age = 65.4, SD = 9.0 years). Association fibers showed the most pronounced declines over time. Advanced age was associated with greater longitudinal changes in RD and FA, independent of fiber type. Furthermore, older age was associated with longitudinal RD increases in late-developing, but not early-developing projection fibers. These findings demonstrate the increased vulnerability of later developing WM regions and support the last-in-first-out hypothesis of brain aging. PMID:26481675

  11. Relationship between fractional anisotropy of cerebral white matter and metabolite concentrations measured using (1)H magnetic resonance spectroscopy in healthy adults.

    PubMed

    Wijtenburg, S A; McGuire, S A; Rowland, L M; Sherman, P M; Lancaster, J L; Tate, D F; Hardies, L J; Patel, B; Glahn, D C; Hong, L E; Fox, P T; Kochunov, P

    2013-02-01

    Fractional anisotropy (FA) of water diffusion in cerebral white matter (WM), derived from diffusion tensor imaging (DTI), is a sensitive index of microscopic WM integrity. Physiological and metabolic factors that explain intersubject variability in FA values were evaluated in two cohorts of healthy adults of different age spans (N=65, range: 28-50years; and N=25, age=66.6±6.2, range: 57-80years). Single voxel magnetic resonance spectroscopy (MRS) was used to measure N-acetylaspartate (NAA), total choline-containing compounds, and total creatine, bilaterally in an associative WM tract: anterior corona radiata (ACR). FA values were calculated for the underlying, proximal and two distal WM regions. Two-stage regression analysis was used to calculate the proportion of variability in FA values explained by spectroscopy measurements, at the first stage, and subject's age, at the second stage. WM NAA concentration explained 23% and 66% of intersubject variability (p<0.001) in the FA of the underlying WM in the younger and older cohorts, respectively. WM NAA concentration also explained a significant proportion of variability in FA of the genu of corpus callosum (CC), a proximal WM tract where some of the fibers contained within the spectroscopic voxel decussate. NAA concentrations also explained a significant proportion of variability in the FA values in the splenium of CC, a distal WM tract that also carries associative fibers, in both cohorts. These results suggest that MRS measurements explained a significant proportion of variability in FA values in both proximal and distal WM tracts that carry similar fiber-types.

  12. Cerebral Small Vessel Disease and Arterial Stiffness: Tsunami Effect in the Brain?

    PubMed Central

    Saji, Naoki; Toba, Kenji; Sakurai, Takashi

    2016-01-01

    Background Cerebral small vessel diseases, including silent lacunar infarcts, white matter hyperintensities, and microbleeds, pose a risk for cerebrovascular disease, cognitive impairment, and the geriatric syndrome via effects on arterial stiffness. However, the vascular, physiological, and metabolic roles of arterial stiffness in cerebral small vessel diseases remain unclear. Summary Arterial stiffness can be assessed using various indicators such as the ankle-brachial index, pulse wave velocity, cardio-ankle vascular index, and augmentation index. Arterial stiffness is independently associated with all components of cerebral small vessel disease including silent lacunar infarcts, white matter hyperintensities, and microbleeds, although there are some methodological differences between the various surrogate markers. Evidence of arterial stiffness indicates microvessel arteriosclerosis presenting with vascular endothelial dysfunction. Further, vascular narrowing due to atherosclerosis and vascular stiffness due to lipohyalinosis can accelerate the pulse waves. This hemodynamic stress, pulsatile pressure, or blood pressure variability can cause a ‘tsunami effect’ towards the cerebral parenchyma and lead to cerebral small vessel disease. Previous studies have shown that silent lacunar infarcts and white matter hyperintensities are strongly associated with arterial stiffness. However, the association between microbleeds and arterial stiffness remains controversial, as there are two vessel mechanisms related to microbleeds: cerebral amyloid angiopathy and hypertensive small vessel disease. Key Messages Cerebral small vessel disease with associated arterial stiffness is a risk factor for silent cerebral lesions, stroke, and cognitive impairment. Improvement of the living environment, management of risk factors, and innovation and development of novel drugs that improve arterial stiffness may suppress the progression of cerebral small vessel disease, and may reduce

  13. White Button Mushrooms Increase Microbial Diversity and Accelerate the Resolution of Citrobacter rodentium Infection in Mice123

    PubMed Central

    Varshney, Jyotika; Ooi, Jot Hui; Jayarao, Bhushan M.; Albert, Istvan; Fisher, Jenny; Smith, Rhonda L.; Patterson, Andrew D.; Cantorna, Margherita T.

    2013-01-01

    The effect of feeding C57BL/6 mice white button (WB) mushrooms or control (CTRL) diets for 6 wk was determined on the bacterial microflora, urinary metabolome, and resistance to a gastrointestinal (GI) pathogen. Feeding mice a diet containing 1 g WB mushrooms/100 g diet resulted in changes in the microflora that were evident at 2 wk and stabilized after 4 wk of WB feeding. Compared with CTRL-fed mice, WB feeding (1 g/100 g diet) increased the diversity of the microflora and reduced potentially pathogenic (e.g., Clostridia) bacteria in the GI tract. Bacteria from the Bacteroidetes phylum increased and the Firmicutes phylum decreased in mushroom-fed mice compared with CTRL. The changes in the microflora were also reflected in the urinary metabolome that showed a metabolic shift in the WB-fed compared with the CTRL-fed mice. The WB feeding and changes in the microbiome were associated with fewer inflammatory cells and decreased colitis severity in the GI mucosa following Citrobacter rodentium infection compared with CTRL. Paradoxically, the clearance of C. rodentium infection did not differ even though Ifn-γ and Il-17 were higher in the colons of the WB-fed mice compared with CTRL. Adding modest amounts of WB mushrooms (1 g/100 g diet) to the diet changed the composition of the normal flora and the urinary metabolome of mice and these changes resulted in better control of inflammation and resolution of infection with C. rodentium. PMID:23343678

  14. Monitoring for volcano-hydrothermal activity using continuous gravity and local ground acceleration measurements: New deployments at Inferno Crater, Waimangu and White Island, New Zealand

    NASA Astrophysics Data System (ADS)

    Jolly, Arthur; Fournier, Nico; Cole-Baker, Jeremy; Miller, Craig

    2010-05-01

    Volcanoes with crater lakes are often characterised by shallow hydrothermal systems which display cyclic behaviour (temperature, lake level, chemistry, etc.) and shallow seismic tremor. Present monitoring programmes in New Zealand include routine collection of these observables, but the associated shallow sub-surface processes are still inadequately modelled and poorly understood. Models would be better constrained with the incorporation of additional geophysical parameters. To this end, we have established a new test programme to continuously monitor for micro-gravity variations at New Zealand volcanoes. We utilise a Micro-g-LaCoste gPhone relative gravity meter having 1 Hz sample rate and a measurement precision of 1 microgal to test the viability of gravity monitoring for volcano-hydrothermal systems. We have initially tested the new sensor in a short term deployment (~2 months) at Inferno Crater, Waimangu, New Zealand. Inferno shows dramatic variations in crater lake level (> 7 m range), temperature (>40o C range) and hydrothermally derived tremor, all over a period of ~5 weeks. The amplitude and period of these observables are ideal for testing gravity variations associated with a cycling hydrothermal system because several cycles can be obtained in a relatively short campaign. We have deployed the gravity sensor into a buried vault having a stable concrete base to minimise local environmental influences. This vault is located ~20 meters from Inferno Lake edge (at high stand) and offers sufficient noise reduction to measure the gravitational effects associated with lake level changes. We will show results for the new gravity meter including raw relative gravity measurements and first order corrections (earth-tide, ocean loading, sensor level, temperature, and barometric pressure) to obtain both residual gravity and overprinted local ground accelerations (earthquakes and local tremor). To examine the effects of local ground vibrations on the gravity meter, we

  15. Cerebral Palsy

    MedlinePlus

    Cerebral palsy is a group of disorders that affect a person's ability to move and to maintain balance ... do not get worse over time. People with cerebral palsy may have difficulty walking. They may also have ...

  16. Auditory Selective Attention in Cerebral-Palsied Individuals.

    ERIC Educational Resources Information Center

    Laraway, Lee Ann

    1985-01-01

    To examine differences between auditory selective attention abilities of normal and cerebral-palsied individuals, 23 cerebral-palsied and 23 normal subjects (5-21) were asked to repeat a series of 30 items in presence of intermittent white noise. Results indicated that cerebral-palsied individuals perform significantly more poorly when the…

  17. Hyperglycemia accelerates apparent diffusion coefficient-defined lesion growth after focal cerebral ischemia in rats with and without features of metabolic syndrome.

    PubMed

    Tarr, David; Graham, Delyth; Roy, Lisa A; Holmes, William M; McCabe, Christopher; Mhairi Macrae, I; Muir, Keith W; Dewar, Deborah

    2013-10-01

    Poststroke hyperglycemia is associated with a poor outcome yet clinical management is inadequately informed. We sought to determine whether clinically relevant levels of hyperglycemia exert detrimental effects on the early evolution of focal ischemic brain damage, as determined by magnetic resonance imaging, in normal rats and in those modeling the 'metabolic syndrome'. Wistar Kyoto (WKY) or fructose-fed spontaneously hypertensive stroke-prone (ffSHRSP) rats were randomly allocated to groups for glucose or vehicle administration before permanent middle cerebral artery occlusion. Diffusion-weighted imaging was carried out over the first 4 hours after middle cerebral artery occlusion and lesion volume calculated from apparent diffusion coefficient maps. Infarct volume and immunostaining for markers of oxidative stress were measured in the fixed brain sections at 24 hours. Hyperglycemia rapidly exacerbated early ischemic damage in both WKY and ffSHRSP rats but increased infarct volume only in WKY rats. There was only limited evidence of oxidative stress in hyperglycemic animals. Acute hyperglycemia, at clinically relevant levels, exacerbates early ischemic damage in both normal and metabolic syndrome rats. Management of hyperglycemia may have greatest benefit when performed in the acute phase after stroke in the absence or presence of comorbidities.

  18. Cerebral microbleeds topography and cerebrospinal fluid biomarkers in cognitive impairment.

    PubMed

    Shams, Sara; Granberg, Tobias; Martola, Juha; Charidimou, Andreas; Li, Xiaozhen; Shams, Mana; Fereshtehnejad, Seyed-Mohammad; Cavallin, Lena; Aspelin, Peter; Wiberg-Kristoffersen, Maria; Wahlund, Lars-Olof

    2017-03-01

    Cerebral microbleeds, a marker of small vessel disease, are thought to be of importance in cognitive impairment. We aimed to study topographical distribution of cerebral microbleeds, and their involvement in disease pathophysiology, reflected by cerebrospinal fluid biomarkers; 1039 patients undergoing memory investigation underwent lumbar puncture and a brain magnetic resonance imaging scan. Cerebrospinal fluid samples were analyzed for amyloid β(Aβ)42, total tau(T-tau), tau phosphorylated at threonine 18(P-tau) and cerebrospinal fluid/serum albumin ratios. Magnetic resonance imaging sequences were evaluated for small vessel disease markers, including cerebral microbleeds, white matter hyperintensities and lacunes. Low Aβ42 levels were associated with lobar cerebral microbleeds in the whole cohort and Alzheimer's disease ( P < 0.001). High cerebrospinal fluid/serum albumin ratios were seen with increased number of cerebral microbleeds in the brainstem ( P < 0.001). There were tendencies for increased Aβ42 levels and decreased Tau levels with deep and infratentorial cerebral microbleeds ( P < 0.05). Lobar cerebral microbleeds were associated with white matter hyperintensities and lacunes ( P < 0.001). Probable cerebral amyloid angiopathy-related cerebral microbleeds were associated with low Aβ42 levels and lacunes, whereas probable cerebral amyloid angiopathy-unrelated cerebral microbleeds were associated with white matter hyperintensities ( P < 0.001). Our findings show that cerebral microbleed distribution is associated with different patterns of cerebrospinal fluid biomarkers, supporting different pathogenesis of deep/infratentorial and lobar cerebral microbleeds.

  19. The Impact of Cognitive Training on Cerebral White Matter in Community-Dwelling Elderly: One-Year Prospective Longitudinal Diffusion Tensor Imaging Study

    PubMed Central

    Cao, Xinyi; Yao, Ye; Li, Ting; Cheng, Yan; Feng, Wei; Shen, Yuan; Li, Qingwei; Jiang, Lijuan; Wu, Wenyuan; Wang, Jijun; Sheng, Jianhua; Feng, Jianfeng; Li, Chunbo

    2016-01-01

    It has been shown that cognitive training (CogTr) is effective and recuperative for older adults, and can be used to fight against cognitive decline. In this study, we investigated whether behavioural gains from CogTr would extend to white matter (WM) microstructure, and whether training-induced changes in WM integrity would be associated with improvements in cognitive function, using diffusion tensor imaging (DTI). 48 healthy community elderly were either assigned to multi-domain or single-domain CogTr groups to receive 24 sessions over 12 weeks, or to a control group. DTI was performed at both baseline and 12-month follow-up. Positive effects of multi-domain CogTr on long-term changes in DTI indices were found in posterior parietal WM. Participants in the multi-domain group showed a trend of long-term decrease in axial diffusivity (AD) without significant change in fractional anisotropy (FA), mean diffusivity (MD) or radial diffusivity (RD), while those in the control group displayed a significant FA decrease, and an increase in MD and RD. In addition, significant relationships between an improvement in processing speed and changes in RD, MD and AD were found in the multi-domain group. These findings support the hypothesis that plasticity of WM can be modified by CogTr, even in late adulthood. PMID:27628682

  20. TM4SF20 ancestral deletion and susceptibility to a pediatric disorder of early language delay and cerebral white matter hyperintensities.

    PubMed

    Wiszniewski, Wojciech; Hunter, Jill V; Hanchard, Neil A; Willer, Jason R; Shaw, Chad; Tian, Qi; Illner, Anna; Wang, Xueqing; Cheung, Sau W; Patel, Ankita; Campbell, Ian M; Gelowani, Violet; Hixson, Patricia; Ester, Audrey R; Azamian, Mahshid S; Potocki, Lorraine; Zapata, Gladys; Hernandez, Patricia P; Ramocki, Melissa B; Santos-Cortez, Regie L P; Wang, Gao; York, Michele K; Justice, Monica J; Chu, Zili D; Bader, Patricia I; Omo-Griffith, Lisa; Madduri, Nirupama S; Scharer, Gunter; Crawford, Heather P; Yanatatsaneejit, Pattamawadee; Eifert, Anna; Kerr, Jeffery; Bacino, Carlos A; Franklin, Adiaha I A; Goin-Kochel, Robin P; Simpson, Gayle; Immken, Ladonna; Haque, Muhammad E; Stosic, Marija; Williams, Misti D; Morgan, Thomas M; Pruthi, Sumit; Omary, Reed; Boyadjiev, Simeon A; Win, Kay K; Thida, Aye; Hurles, Matthew; Hibberd, Martin Lloyd; Khor, Chiea Chuen; Van Vinh Chau, Nguyen; Gallagher, Thomas E; Mutirangura, Apiwat; Stankiewicz, Pawel; Beaudet, Arthur L; Maletic-Savatic, Mirjana; Rosenfeld, Jill A; Shaffer, Lisa G; Davis, Erica E; Belmont, John W; Dunstan, Sarah; Simmons, Cameron P; Bonnen, Penelope E; Leal, Suzanne M; Katsanis, Nicholas; Lupski, James R; Lalani, Seema R

    2013-08-08

    White matter hyperintensities (WMHs) of the brain are important markers of aging and small-vessel disease. WMHs are rare in healthy children and, when observed, often occur with comorbid neuroinflammatory or vasculitic processes. Here, we describe a complex 4 kb deletion in 2q36.3 that segregates with early childhood communication disorders and WMH in 15 unrelated families predominantly from Southeast Asia. The premature brain aging phenotype with punctate and multifocal WMHs was observed in ~70% of young carrier parents who underwent brain MRI. The complex deletion removes the penultimate exon 3 of TM4SF20, a gene encoding a transmembrane protein of unknown function. Minigene analysis showed that the resultant net loss of an exon introduces a premature stop codon, which, in turn, leads to the generation of a stable protein that fails to target to the plasma membrane and accumulates in the cytoplasm. Finally, we report this deletion to be enriched in individuals of Vietnamese Kinh descent, with an allele frequency of about 1%, embedded in an ancestral haplotype. Our data point to a constellation of early language delay and WMH phenotypes, driven by a likely toxic mechanism of TM4SF20 truncation, and highlight the importance of understanding and managing population-specific low-frequency pathogenic alleles.

  1. The Impact of Cognitive Training on Cerebral White Matter in Community-Dwelling Elderly: One-Year Prospective Longitudinal Diffusion Tensor Imaging Study.

    PubMed

    Cao, Xinyi; Yao, Ye; Li, Ting; Cheng, Yan; Feng, Wei; Shen, Yuan; Li, Qingwei; Jiang, Lijuan; Wu, Wenyuan; Wang, Jijun; Sheng, Jianhua; Feng, Jianfeng; Li, Chunbo

    2016-09-15

    It has been shown that cognitive training (CogTr) is effective and recuperative for older adults, and can be used to fight against cognitive decline. In this study, we investigated whether behavioural gains from CogTr would extend to white matter (WM) microstructure, and whether training-induced changes in WM integrity would be associated with improvements in cognitive function, using diffusion tensor imaging (DTI). 48 healthy community elderly were either assigned to multi-domain or single-domain CogTr groups to receive 24 sessions over 12 weeks, or to a control group. DTI was performed at both baseline and 12-month follow-up. Positive effects of multi-domain CogTr on long-term changes in DTI indices were found in posterior parietal WM. Participants in the multi-domain group showed a trend of long-term decrease in axial diffusivity (AD) without significant change in fractional anisotropy (FA), mean diffusivity (MD) or radial diffusivity (RD), while those in the control group displayed a significant FA decrease, and an increase in MD and RD. In addition, significant relationships between an improvement in processing speed and changes in RD, MD and AD were found in the multi-domain group. These findings support the hypothesis that plasticity of WM can be modified by CogTr, even in late adulthood.

  2. Traumatic Brain Injury by a Closed Head Injury Device Induces Cerebral Blood Flow Changes and Microhemorrhages

    PubMed Central

    Kallakuri, Srinivasu; Bandaru, Sharath; Zakaria, Nisrine; Shen, Yimin; Kou, Zhifeng; Zhang, Liying; Haacke, Ewart Mark; Cavanaugh, John M

    2015-01-01

    Objectives: Traumatic brain injury is a poly-pathology characterized by changes in the cerebral blood flow, inflammation, diffuse axonal, cellular, and vascular injuries. However, studies related to understanding the temporal changes in the cerebral blood flow following traumatic brain injury extending to sub-acute periods are limited. In addition, knowledge related to microhemorrhages, such as their detection, localization, and temporal progression, is important in the evaluation of traumatic brain injury. Materials and Methods: Cerebral blood flow changes and microhemorrhages in male Sprague Dawley rats at 4 h, 24 h, 3 days, and 7 days were assessed following a closed head injury induced by the Marmarou impact acceleration device (2 m height, 450 g brass weight). Cerebral blood flow was measured by arterial spin labeling. Microhemorrhages were assessed by susceptibility-weighted imaging and Prussian blue histology. Results: Traumatic brain injury rats showed reduced regional and global cerebral blood flow at 4 h and 7 days post-injury. Injured rats showed hemorrhagic lesions in the cortex, corpus callosum, hippocampus, and brainstem in susceptibility-weighted imaging. Injured rats also showed Prussian blue reaction products in both the white and gray matter regions up to 7 days after the injury. These lesions were observed in various areas of the cortex, corpus callosum, hippocampus, thalamus, and midbrain. Conclusions: These results suggest that changes in cerebral blood flow and hemorrhagic lesions can persist for sub-acute periods after the initial traumatic insult in an animal model. In addition, microhemorrhages otherwise not seen by susceptibility-weighted imaging are present in diverse regions of the brain. The combination of altered cerebral blood flow and microhemorrhages can potentially be a source of secondary injury changes following traumatic brain injury and may need to be taken into consideration in the long-term care of these cases. PMID:26605126

  3. Oligodendrogenesis after cerebral ischemia

    PubMed Central

    Zhang, Ruilan; Chopp, Michael; Zhang, Zheng Gang

    2013-01-01

    Neural stem cells in the subventricular zone (SVZ) of the lateral ventricle of adult rodent brain generate oligodendrocyte progenitor cells (OPCs) that disperse throughout the corpus callosum and striatum where some of OPCs differentiate into mature oligodendrocytes. Studies in animal models of stroke demonstrate that cerebral ischemia induces oligodendrogenesis during brain repair processes. This article will review evidence of stroke-induced proliferation and differentiation of OPCs that are either resident in white matter or are derived from SVZ neural progenitor cells and of therapies that amplify endogenous oligodendrogenesis in ischemic brain. PMID:24194700

  4. Cerebral Paragonimiasis.

    PubMed

    Miyazaki, I

    1975-01-01

    The first case of cerebral paragonimiasis was reported by Otani in Japan in 1887. This was nine years after Kerbert's discovery of the fluke in the lungs of Bengal tigers and seven years after a human pulmonary infection by the fluke was demonstrated by Baelz and Manson. The first case was a 26-year-old man who had been suffering from cough and hemosputum for one year. The patient developed convulsive seizures with subsequent coma and died. The postmortem examination showed cystic lesions in the right frontal and occipital lobes. An adult fluke was found in the occipital lesion and another was seen in a gross specimen of normal brain tissue around the affected occipital lobe. Two years after Otani's discovery, at autopsy a 29-year-old man with a history of Jacksonian seizure was reported as having cerebral paragonimiasis. Some time later, however, it was confirmed that the case was actually cerebral schistosomiasis japonica. Subsequently, cases of cerebral paragonimiasis were reported. However, the majority of these cases were not confirmed histologically. It was pointed out that some of these early cases were probably not Paragonimus infection. After World War II, reviews as well as case reports were published. Recently, investigations have been reported from Korea, with a clinicla study on 62 cases of cerebral paragonimiasis seen at the Neurology Department of the National Medical Center, Seoul, between 1958 and 1964. In 1971 Higashi described a statistical study on 105 cases of cerebral paragonimiasis that had been treated surgically in Japan.

  5. Cerebral Palsy (For Parents)

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old Cerebral Palsy KidsHealth > For Parents > Cerebral Palsy A A A ... kids who are living with the condition. About Cerebral Palsy Cerebral palsy is one of the most common ...

  6. Cerebral palsy - resources

    MedlinePlus

    Resources - cerebral palsy ... The following organizations are good resources for information on cerebral palsy : National Institute of Neurological Disorders and Stroke -- www.ninds.nih.gov/disorders/cerebral_palsy/cerebral_palsy. ...

  7. Genetics of cerebral small vessel disease.

    PubMed

    Choi, Jay Chol

    2015-01-01

    Cerebral small vessel disease (SVD) is an important cause of stroke and cognitive impairment among the elderly and is a more frequent cause of stroke in Asia than in the US or Europe. Although traditional risk factors such as hypertension or diabetes mellitus are important in the development of cerebral SVD, the exact pathogenesis is still uncertain. Both, twin and family history studies suggest heritability of sporadic cerebral SVD, while the candidate gene study and the genome-wide association study (GWAS) are mainly used in genetic research. Robust associations between the candidate genes and occurrence of various features of sporadic cerebral SVD, such as lacunar infarction, intracerebral hemorrhage, or white matter hyperintensities, have not yet been elucidated. GWAS, a relatively new technique, overcomes several shortcomings of previous genetic techniques, enabling the detection of several important genetic loci associated with cerebral SVD. In addition to the more common, sporadic cerebral SVD, several single-gene disorders causing cerebral SVD have been identified. The number of reported cases is increasing as the clinical features become clear and diagnostic examinations are more readily available. These include cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy, COL4A1-related cerebral SVD, autosomal dominant retinal vasculopathy with cerebral leukodystrophy, and Fabry disease. These rare single-gene disorders are expected to play a crucial role in our understanding of cerebral SVD pathogenesis by providing animal models for the identification of cellular, molecular, and biochemical changes underlying cerebral small vessel damage.

  8. Genetics of Cerebral Small Vessel Disease

    PubMed Central

    2015-01-01

    Cerebral small vessel disease (SVD) is an important cause of stroke and cognitive impairment among the elderly and is a more frequent cause of stroke in Asia than in the US or Europe. Although traditional risk factors such as hypertension or diabetes mellitus are important in the development of cerebral SVD, the exact pathogenesis is still uncertain. Both, twin and family history studies suggest heritability of sporadic cerebral SVD, while the candidate gene study and the genome-wide association study (GWAS) are mainly used in genetic research. Robust associations between the candidate genes and occurrence of various features of sporadic cerebral SVD, such as lacunar infarction, intracerebral hemorrhage, or white matter hyperintensities, have not yet been elucidated. GWAS, a relatively new technique, overcomes several shortcomings of previous genetic techniques, enabling the detection of several important genetic loci associated with cerebral SVD. In addition to the more common, sporadic cerebral SVD, several single-gene disorders causing cerebral SVD have been identified. The number of reported cases is increasing as the clinical features become clear and diagnostic examinations are more readily available. These include cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy, COL4A1-related cerebral SVD, autosomal dominant retinal vasculopathy with cerebral leukodystrophy, and Fabry disease. These rare single-gene disorders are expected to play a crucial role in our understanding of cerebral SVD pathogenesis by providing animal models for the identification of cellular, molecular, and biochemical changes underlying cerebral small vessel damage. PMID:25692103

  9. Cerebral palsy.

    PubMed

    Colver, Allan; Fairhurst, Charles; Pharoah, Peter O D

    2014-04-05

    The syndrome of cerebral palsy encompasses a large group of childhood movement and posture disorders. Severity, patterns of motor involvement, and associated impairments such as those of communication, intellectual ability, and epilepsy vary widely. Overall prevalence has remained stable in the past 40 years at 2-3·5 cases per 1000 livebirths, despite changes in antenatal and perinatal care. The few studies available from developing countries suggest prevalence of comparable magnitude. Cerebral palsy is a lifelong disorder; approaches to intervention, whether at an individual or environmental level, should recognise that quality of life and social participation throughout life are what individuals with cerebral palsy seek, not improved physical function for its own sake. In the past few years, the cerebral palsy community has learned that the evidence of benefit for the numerous drugs, surgery, and therapies used over previous decades is weak. Improved understanding of the role of multiple gestation in pathogenesis, of gene environment interaction, and how to influence brain plasticity could yield significant advances in treatment of the disorder. Reduction in the prevalence of post-neonatal cerebral palsy, especially in developing countries, should be possible through improved nutrition, infection control, and accident prevention.

  10. Cerebral Autosomal Dominant Arteriopathy with Subcortical Infacts and Leukoencephalopathy (CADASIL)

    MedlinePlus

    ... portion of the brain immediately below the cerebral cortex. White matter and the deep gray structures constitute ... one side of the body), walking difficulty and visual impairment Rarely, epileptic seizures How can CADASIL be ...

  11. Cerebral Malaria.

    PubMed

    Marsden, P D; Bruce-Chwatt, L J

    1975-01-01

    Cerebral malaria is an acute diffuse encephalopathy associated only with Plasmodium falciparum. It is probably a consequence of the rapid proliferation of the parasites in the body of man in relation to red cell invasion, and results in stagnation of blood flow in cerebralcapillaries with thromobotic occlusion of large numbers of cerebral capillaries. The subsequent cerebral pathology is cerebral infarction with haemorrhage and cerebral oedema. The wide prevalence of P. falciparum in highly endemic areas results in daily challenges to patients from several infected mosquitoes. It is thus important to understand the characteristics of P. falciparum, since this is one of the most important protozoan parasites of man and severe infection from it constitutes one of the few real clinical emergencies in tropical medicine. One of the more important aspects of the practice of medicine in the tropics is to establish a good understanding of the pattern of medical practice in that area. This applies to malaria as well as to other diseases. The neophyte might be somewhat surprised to learn, for example that an experienced colleague who lives in a holoendemic malarious area such as West Africa, sees no cerebral malaria. But the explanation is simple when the doctor concerned has a practice which involves treating adults only. Cerebral malaria is rare in adults, because in highly endemic areas, by the age of 1 year most of the infants in a group under study have already experienced their first falciparum infection. By the time they reach adult life, they have a solid immunity against severe falciparum infections. In fact, "clinical malaria" could occur in such a group under only two circumstances: 1) in pregnancy, a patent infection with P. falciparum might develop, probably due to an IgG drain across the placenta to the foetus;2) in an individual who has constantly taken antimalarials and who may have an immunity at such a low level that when antimalarial therapy is interrupted

  12. Linear Accelerators

    NASA Astrophysics Data System (ADS)

    Sidorin, Anatoly

    2010-01-01

    In linear accelerators the particles are accelerated by either electrostatic fields or oscillating Radio Frequency (RF) fields. Accordingly the linear accelerators are divided in three large groups: electrostatic, induction and RF accelerators. Overview of the different types of accelerators is given. Stability of longitudinal and transverse motion in the RF linear accelerators is briefly discussed. The methods of beam focusing in linacs are described.

  13. White House

    MedlinePlus

    ... to main content Jump to navigation the WHITE HOUSE President Donald J. Trump Get in Touch Home ... News Read the latest news from the White House Video Gallery View the most recent videos from ...

  14. Cerebral malaria

    PubMed Central

    Newton, C.; Hien, T. T.; White, N.

    2000-01-01

    Cerebral malaria may be the most common non-traumatic encephalopathy in the world. The pathogenesis is heterogenous and the neurological complications are often part of a multisystem dysfunction. The clinical presentation and pathophysiology differs between adults and children. Recent studies have elucidated the molecular mechanisms of pathogenesis and raised possible interventions. Antimalarial drugs, however, remain the only intervention that unequivocally affects outcome, although increasing resistance to the established antimalarial drugs is of grave concern. Artemisinin derivatives have made an impact on treatment, but other drugs may be required. With appropriate antimalarial drugs, the prognosis of cerebral malaria often depends on the management of other complications—for example, renal failure and acidosis. Neurological sequelae are increasingly recognised, but further research on the pathogenesis of coma and neurological damage is required to develop other ancillary treatments.

 PMID:10990500

  15. Tract-based analysis of white matter degeneration in Alzheimer's disease.

    PubMed

    Lee, S-H; Coutu, J-P; Wilkens, P; Yendiki, A; Rosas, H D; Salat, D H

    2015-08-20

    Although much prior work has focused on the known cortical pathology that defines Alzheimer's disease (AD) histologically, recent work has additionally demonstrated substantial damage to the cerebral white matter in this condition. While there is large evidence of diffuse damage to the white matter in AD, it is unclear whether specific white matter tracts exhibit a more accelerated pattern of damage and whether the damage is associated with the classical neurodegenerative changes of AD. In this study, we investigated microstructural differences in the large fascicular bundles of the cerebral white matter of individuals with AD and mild cognitive impairment (MCI), using recently developed automated diffusion tractography procedures in the Alzheimer's disease Neuroimaging Initiative (ADNI) dataset. Eighteen major fiber bundles in a total of 36 individuals with AD, 81 MCI and 60 control participants were examined with the TRActs Constrained by UnderLying Anatomy (TRACULA) procedure available as part of the FreeSurfer image processing software package. For each fiber bundle, the mean fractional anisotropy (FA), and mean, radial and axial diffusivities were calculated. Individuals with AD had increased diffusivities in both left and right cingulum-angular bundles compared to control participants (p<0.001). Individuals with MCI also had increased axial and mean diffusivities and increased FA in both cingulum-angular bundles compared to control participants (p<0.05) and decreased radial diffusivity compared to individuals with AD (p<0.05). We additionally examined how white matter deterioration relates to hippocampal volume, a traditional imaging measure of AD pathology, and found the strongest negative correlations in AD patients between hippocampal volume and the diffusivities of the cingulum-angular and cingulum-cingulate gyrus bundles and of the corticospinal tracts (p<0.05). However, statistically controlling for hippocampal volume did not remove all group

  16. Cerebral involvement in multiple myeloma: case report.

    PubMed Central

    McCarthy, J; Proctor, S J

    1978-01-01

    Cerebral myeloma in a 49-year-old white man took the form of diffuse arachnoid infiltration, intracerebral perivascular cuffing, and frank intracerebral invasion. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 PMID:417093

  17. Can Accelerators Accelerate Learning?

    NASA Astrophysics Data System (ADS)

    Santos, A. C. F.; Fonseca, P.; Coelho, L. F. S.

    2009-03-01

    The 'Young Talented' education program developed by the Brazilian State Funding Agency (FAPERJ) [1] makes it possible for high-schools students from public high schools to perform activities in scientific laboratories. In the Atomic and Molecular Physics Laboratory at Federal University of Rio de Janeiro (UFRJ), the students are confronted with modern research tools like the 1.7 MV ion accelerator. Being a user-friendly machine, the accelerator is easily manageable by the students, who can perform simple hands-on activities, stimulating interest in physics, and getting the students close to modern laboratory techniques.

  18. PARTICLE ACCELERATOR

    DOEpatents

    Teng, L.C.

    1960-01-19

    ABS>A combination of two accelerators, a cyclotron and a ring-shaped accelerator which has a portion disposed tangentially to the cyclotron, is described. Means are provided to transfer particles from the cyclotron to the ring accelerator including a magnetic deflector within the cyclotron, a magnetic shield between the ring accelerator and the cyclotron, and a magnetic inflector within the ring accelerator.

  19. Cerebral blood flow in small vessel disease: A systematic review and meta-analysis.

    PubMed

    Shi, Yulu; Thrippleton, Michael J; Makin, Stephen D; Marshall, Ian; Geerlings, Mirjam I; de Craen, Anton Jm; van Buchem, Mark A; Wardlaw, Joanna M

    2016-10-01

    White matter hyperintensities are frequent on neuroimaging of older people and are a key feature of cerebral small vessel disease. They are commonly attributed to chronic hypoperfusion, although whether low cerebral blood flow is cause or effect is unclear. We systematically reviewed studies that assessed cerebral blood flow in small vessel disease patients, performed meta-analysis and sensitivity analysis of potential confounders. Thirty-eight studies (n = 4006) met the inclusion criteria, including four longitudinal and 34 cross-sectional studies. Most cerebral blood flow data were from grey matter. Twenty-four cross-sectional studies (n = 1161) were meta-analysed, showing that cerebral blood flow was lower in subjects with more white matter hyperintensity, globally and in most grey and white matter regions (e.g. mean global cerebral blood flow: standardised mean difference-0.71, 95% CI -1.12, -0.30). These cerebral blood flow differences were attenuated by excluding studies in dementia or that lacked age-matching. Four longitudinal studies (n = 1079) gave differing results, e.g., more baseline white matter hyperintensity predated falling cerebral blood flow (3.9 years, n = 575); cerebral blood flow was low in regions that developed white matter hyperintensity (1.5 years, n = 40). Cerebral blood flow is lower in subjects with more white matter hyperintensity cross-sectionally, but evidence for falling cerebral blood flow predating increasing white matter hyperintensity is conflicting. Future studies should be longitudinal, obtain more white matter data, use better age-correction and stratify by clinical diagnosis.

  20. Cerebral microbleeds in a neonatal rat model

    PubMed Central

    Carusillo Theriault, Brianna; Woo, Seung Kyoon; Karimy, Jason K.; Keledjian, Kaspar; Stokum, Jesse A.; Sarkar, Amrita; Coksaygan, Turhan; Ivanova, Svetlana; Gerzanich, Volodymyr

    2017-01-01

    Background In adult humans, cerebral microbleeds play important roles in neurodegenerative diseases but in neonates, the consequences of cerebral microbleeds are unknown. In rats, a single pro-angiogenic stimulus in utero predisposes to cerebral microbleeds after birth at term, a time when late oligodendrocyte progenitors (pre-oligodendrocytes) dominate in the rat brain. We hypothesized that two independent pro-angiogenic stimuli in utero would be associated with a high likelihood of perinatal microbleeds that would be severely damaging to white matter. Methods Pregnant Wistar rats were subjected to intrauterine ischemia (IUI) and low-dose maternal lipopolysaccharide (mLPS) at embryonic day (E) 19. Pups were born vaginally or abdominally at E21-22. Brains were evaluated for angiogenic markers, microhemorrhages, myelination and axonal development. Neurological function was assessed out to 6 weeks. Results mRNA (Vegf, Cd31, Mmp2, Mmp9, Timp1, Timp2) and protein (CD31, MMP2, MMP9) for angiogenic markers, in situ proteolytic activity, and collagen IV immunoreactivity were altered, consistent with an angiogenic response. Vaginally delivered pups exposed to prenatal IUI+mLPS had spontaneous cerebral microbleeds, abnormal neurological function, and dysmorphic, hypomyelinated white matter and axonopathy. Pups exposed to the same pro-angiogenic stimuli in utero but delivered abdominally had minimal cerebral microbleeds, preserved myelination and axonal development, and neurological function similar to naïve controls. Conclusions In rats, pro-angiogenic stimuli in utero can predispose to vascular fragility and lead to cerebral microbleeds. The study of microbleeds in the neonatal rat brain at full gestation may give insights into the consequences of microbleeds in human preterm infants during critical periods of white matter development. PMID:28158198

  1. Cerebral Hypoperfusion Precedes Nausea During Centrifugation

    NASA Technical Reports Server (NTRS)

    Serrador, Jorge M.; Schlegel, Todd T.; Black, F. Owen; Wood, Scott J.

    2004-01-01

    Nausea and motion sickness are important operational concerns for aviators and astronauts. Understanding underlying mechanisms associated with motion sickness may lead to new treatments. The goal of this work was to determine if cerebral blood flow changes precede the development of nausea in motion sick susceptible subjects. Cerebral flow velocity in the middle cerebral artery (transcranial Doppler), blood pressure (Finapres) and end-tidal CO2 were measured while subjects were rotated on a centrifuge (250 degrees/sec). Following 5 min of rotation, subjects were translated 0.504 m off-center, creating a +lGx centripetal acceleration in the nasal-occipital plane. Ten subjects completed the protocol without symptoms while 5 developed nausea (4 while 6ff-center and 1 while rotating on-center). Prior to nausea, subjects had significant increases in blood pressure (+13plus or minus 3 mmHg, P less than 0.05) and cerebrovascular resistance (+46 plus or minus 17%, P less than 0.05) and decreases in cerebral flow velocity both in the second (-13 plus or minus 4%) and last minute (-22 plus or minus 5%) before symptoms (P less than 0.05). In comparison, controls demonstrated no change in blood pressure or cerebrovascular resistance in the last minute of off-center rotation and only a 7 plus or minus 2% decrease in cerebral flow velocity. All subjects had significant hypocapnia (-3.8 plus or minus 0.4 mmHg, P less than 0.05), however this hypocapnia could not fully explain the cerebral hypoperfusion associated with the development of nausea. These data indicate that reductions in cerebral blood flow precede the development of nausea. Further work is necessary to determine what role cerebral hypoperfusion plays in motion sickness and whether cerebral hypoperfusion can be used to predict the development of nausea in susceptible individuals.

  2. Hereditary cerebral small vessel disease and stroke.

    PubMed

    Søndergaard, Christian Baastrup; Nielsen, Jørgen Erik; Hansen, Christine Krarup; Christensen, Hanne

    2017-04-01

    Cerebral small vessel disease is considered hereditary in about 5% of patients and is characterized by lacunar infarcts and white matter hyperintensities on MRI. Several monogenic hereditary diseases causing cerebral small vessel disease and stroke have been identified. The purpose of this systematic review is to provide a guide for determining when to consider molecular genetic testing in patients presenting with small vessel disease and stroke. CADASIL, CARASIL, collagen type IV mutations (including PADMAL), retinal vasculopathy with cerebral leukodystrophy, Fabry disease, hereditary cerebral hemorrhage with amyloidosis, and forkhead box C1 mutations are described in terms of genetics, pathology, clinical manifestation, imaging, and diagnosis. These monogenic disorders are often characterized by early-age stroke, but also by migraine, mood disturbances, vascular dementia and often gait disturbances. Some also present with extra-cerebral manifestations such as microangiopathy of the eyes and kidneys. Many present with clinically recognizable syndromes. Investigations include a thorough family medical history, medical history, neurological examination, neuroimaging, often supplemented by specific examinations e.g of the of vision, retinal changes, as well as kidney and heart function. However molecular genetic analysis is the final gold standard of diagnosis. There are increasing numbers of reports on new monogenic syndromes causing cerebral small vessel disease. Genetic counseling is important. Enzyme replacement therapy is possible in Fabry disease, but treatment options remain overall very limited.

  3. Future accelerators (?)

    SciTech Connect

    John Womersley

    2003-08-21

    I describe the future accelerator facilities that are currently foreseen for electroweak scale physics, neutrino physics, and nuclear structure. I will explore the physics justification for these machines, and suggest how the case for future accelerators can be made.

  4. Vanishing White Matter Disease: A Review with Focus on Its Genetics

    ERIC Educational Resources Information Center

    Pronk, Jan C.; van Kollenburg, Barbara; Scheper, Gert C.; van der Knaap, Marjo S.

    2006-01-01

    Leukoencephalopathy with vanishing white matter (VWM) is an autosomal recessive brain disorder, most often with a childhood onset. Magnetic resonance imaging and spectroscopy indicate that, with time, increasing amounts of cerebral white matter vanish and are replaced by fluid. Autopsy confirms white matter rarefaction and cystic degeneration. The…

  5. Cerebral vascular regulation and brain injury in preterm infants.

    PubMed

    Brew, Nadine; Walker, David; Wong, Flora Y

    2014-06-01

    Cerebrovascular lesions, mainly germinal matrix hemorrhage and ischemic injury to the periventricular white matter, are major causes of adverse neurodevelopmental outcome in preterm infants. Cerebrovascular lesions and neuromorbidity increase with decreasing gestational age, with the white matter predominantly affected. Developmental immaturity in the cerebral circulation, including ongoing angiogenesis and vasoregulatory immaturity, plays a major role in the severity and pattern of preterm brain injury. Prevention of this injury requires insight into pathogenesis. Cerebral blood flow (CBF) is low in the preterm white matter, which also has blunted vasoreactivity compared with other brain regions. Vasoreactivity in the preterm brain to cerebral perfusion pressure, oxygen, carbon dioxide, and neuronal metabolism is also immature. This could be related to immaturity of both the vasculature and vasoactive signaling. Other pathologies arising from preterm birth and the neonatal intensive care environment itself may contribute to impaired vasoreactivity and ineffective CBF regulation, resulting in the marked variations in cerebral hemodynamics reported both within and between infants depending on their clinical condition. Many gaps exist in our understanding of how neonatal treatment procedures and medications have an impact on cerebral hemodynamics and preterm brain injury. Future research directions for neuroprotective strategies include establishing cotside, real-time clinical reference values for cerebral hemodynamics and vasoregulatory capacity and to demonstrate that these thresholds improve long-term outcomes for the preterm infant. In addition, stimulation of vascular development and repair with growth factor and cell-based therapies also hold promise.

  6. Cerebral Palsy (For Kids)

    MedlinePlus

    ... de los dientes Video: Getting an X-ray Cerebral Palsy KidsHealth > For Kids > Cerebral Palsy Print A A ... the things that kids do every day. What's CP? Some kids with CP use wheelchairs and others ...

  7. Cerebral Palsy (For Kids)

    MedlinePlus

    ... Emergency Room? What Happens in the Operating Room? Cerebral Palsy KidsHealth > For Kids > Cerebral Palsy A A A ... the things that kids do every day. What's CP? Some kids with CP use wheelchairs and others ...

  8. Aging and Cerebral Palsy.

    ERIC Educational Resources Information Center

    Networker, 1993

    1993-01-01

    This special edition of "The Networker" contains several articles focusing on aging and cerebral palsy (CP). "Aging and Cerebral Palsy: Pathways to Successful Aging" (Jenny C. Overeynder) reports on the National Invitational Colloquium on Aging and Cerebral Palsy held in April 1993. "Observations from an Observer" (Kathleen K. Barrett) describes…

  9. White Rock

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 19 April 2002) The Science 'White Rock' is the unofficial name for this unusual landform which was first observed during the Mariner 9 mission in the early 1970's. As later analysis of additional data sets would show, White Rock is neither white nor dense rock. Its apparent brightness arises from the fact that the material surrounding it is so dark. Images from the Mars Global Surveyor MOC camera revealed dark sand dunes surrounding White Rock and on the floor of the troughs within it. Some of these dunes are just apparent in the THEMIS image. Although there was speculation that the material composing White Rock could be salts from an ancient dry lakebed, spectral data from the MGS TES instrument did not support this claim. Instead, the White Rock deposit may be the erosional remnant of a previously more continuous occurrence of air fall sediments, either volcanic ash or windblown dust. The THEMIS image offers new evidence for the idea that the original deposit covered a larger area. Approximately 10 kilometers to the southeast of the main deposit are some tiny knobs of similarly bright material preserved on the floor of a small crater. Given that the eolian erosion of the main White Rock deposit has produced isolated knobs at its edges, it is reasonable to suspect that the more distant outliers are the remnants of a once continuous deposit that stretched at least to this location. The fact that so little remains of the larger deposit suggests that the material is very easily eroded and simply blows away. The Story Fingers of hard, white rock seem to jut out like icy daggers across a moody Martian surface, but appearances can be deceiving. These bright, jagged features are neither white, nor icy, nor even hard and rocky! So what are they, and why are they so different from the surrounding terrain? Scientists know that you can't always trust what your eyes see alone. You have to use other kinds of science instruments to measure things that our eyes can

  10. Diagnosis, treatment, and prevention of cerebral palsy.

    PubMed

    O'Shea, Thomas Michael

    2008-12-01

    Cerebral palsy is the most prevalent cause of persisting motor function impairment with a frequency of about 1/500 births. In developed countries, the prevalence rose after introduction of neonatal intensive care, but in the past decade, this trend has reversed. A recent international workshop defined cerebral palsy as "a group of permanent disorders of the development of movement and posture, causing activity limitation, that are attributed to non-progressive disturbances that occurred in the developing fetal or infant brain." In a majority of cases, the predominant motor abnormality is spasticity; other forms of cerebral palsy include dyskinetic (dystonia or choreo-athetosis) and ataxic cerebral palsy. In preterm infants, about one-half of the cases have neuroimaging abnormalities, such as echolucency in the periventricular white matter or ventricular enlargement on cranial ultrasound. Among children born at or near term, about two-thirds have neuroimaging abnormalities, including focal infarction, brain malformations, and periventricular leukomalacia. In addition to the motor impairment, individuals with cerebral palsy may have sensory impairments, cognitive impairment, and epilepsy. Ambulation status, intelligence quotient, quality of speech, and hand function together are predictive of employment status. Mortality risk increases incrementally with increasing number of impairments, including intellectual, limb function, hearing, and vision. The care of individuals with cerebral palsy should include the provision of a primary care medical home for care coordination and support; diagnostic evaluations to identify brain abnormalities, severity of neurologic and functional abnormalities, and associated impairments; management of spasticity; and care for associated problems such as nutritional deficiencies, pain, dental care, bowel and bladder continence, and orthopedic complications. Current strategies to decrease the risk of cerebral palsy include interventions to

  11. White phosphorus

    Integrated Risk Information System (IRIS)

    White phosphorus ; CASRN 7723 - 14 - 0 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic

  12. White Flight

    ERIC Educational Resources Information Center

    Russell, Christine

    1975-01-01

    Focuses on the issue of whether the implementation of school desegregation significantly increases the decline in percentage of resident white. Presents data from a study conducted in 86 Northern school districts from a 91-city study. Data were obtained from statistics published by the Department of Health, Education and Welfare beginning in 1967.…

  13. Hemorrhagic transformation and cerebral edema in acute ischemic stroke: Link to cerebral autoregulation

    PubMed Central

    Castro, Pedro; Azevedo, Elsa; Serrador, Jorge; Rocha, Isabel; Sorond, Farzaneh

    2017-01-01

    Background Hemorrhagic transformation and cerebral edema are feared complications of acute ischemic stroke but mechanisms are poorly understood and reliable early markers are lacking. Early assessment of cerebrovascular hemodynamics may advance our knowledge in both areas. We examined the relationship between dynamic cerebral autoregulation (CA) in the early hours post ischemia, and the risk of developing hemorrhagic transformation and cerebral edema at 24 h post stroke Methods We prospectively enrolled 46 patients from our center with acute ischemic stroke in the middle cerebral artery territory. Cerebrovascular resistance index was calculated. Dynamic CA was assessed by transfer function analysis (coherence, phase and gain) of the spontaneous blood flow velocity and blood pressure oscillations. Infarct volume, hemorrhagic transformation, cerebral edema, and white matter changes were collected from computed tomography performed at presentation and 24 h. Results At admission, phase was lower (worse CA) in patients with hemorrhagic transformation [6.6 ± 30 versus 45 ± 38°; adjusted odds ratio 0.95 (95% confidence internal 0.94–0.98), p = 0.023] and with cerebral edema [6.6 ± 30 versus 45 ± 38°, adjusted odds ratio 0.96 (0.92–0.999), p = 0.044]. Progression to edema was associated with lower cerebrovascular resistance (1.4 ± 0.2 versus 2.3 ± 1.5 mm Hg/cm/s, p = 0.033) and increased cerebral blood flow velocity (51 ± 25 versus 42 ± 17 cm/s, p = 0.033) at presentation. All hemodynamic differences resolved at 3 months Conclusions Less effective CA in the early hour post ischemic stroke is associated with increased risk of hemorrhagic transformation and cerebral edema, possibly reflecting breakthrough hyperperfusion and microvascular injury. Early assessment of dynamic CA could be useful in identifying individuals at risk for these complications. PMID:28017224

  14. LINEAR ACCELERATOR

    DOEpatents

    Colgate, S.A.

    1958-05-27

    An improvement is presented in linear accelerators for charged particles with respect to the stable focusing of the particle beam. The improvement consists of providing a radial electric field transverse to the accelerating electric fields and angularly introducing the beam of particles in the field. The results of the foregoing is to achieve a beam which spirals about the axis of the acceleration path. The combination of the electric fields and angular motion of the particles cooperate to provide a stable and focused particle beam.

  15. White matter and cognition: making the connection.

    PubMed

    Filley, Christopher M; Fields, R Douglas

    2016-11-01

    Whereas the cerebral cortex has long been regarded by neuroscientists as the major locus of cognitive function, the white matter of the brain is increasingly recognized as equally critical for cognition. White matter comprises half of the brain, has expanded more than gray matter in evolution, and forms an indispensable component of distributed neural networks that subserve neurobehavioral operations. White matter tracts mediate the essential connectivity by which human behavior is organized, working in concert with gray matter to enable the extraordinary repertoire of human cognitive capacities. In this review, we present evidence from behavioral neurology that white matter lesions regularly disturb cognition, consider the role of white matter in the physiology of distributed neural networks, develop the hypothesis that white matter dysfunction is relevant to neurodegenerative disorders, including Alzheimer's disease and the newly described entity chronic traumatic encephalopathy, and discuss emerging concepts regarding the prevention and treatment of cognitive dysfunction associated with white matter disorders. Investigation of the role of white matter in cognition has yielded many valuable insights and promises to expand understanding of normal brain structure and function, improve the treatment of many neurobehavioral disorders, and disclose new opportunities for research on many challenging problems facing medicine and society.

  16. Acceleration switch

    DOEpatents

    Abbin, Jr., Joseph P.; Devaney, Howard F.; Hake, Lewis W.

    1982-08-17

    The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

  17. Acceleration switch

    DOEpatents

    Abbin, J.P. Jr.; Devaney, H.F.; Hake, L.W.

    1979-08-29

    The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

  18. ION ACCELERATOR

    DOEpatents

    Bell, J.S.

    1959-09-15

    An arrangement for the drift tubes in a linear accelerator is described whereby each drift tube acts to shield the particles from the influence of the accelerating field and focuses the particles passing through the tube. In one embodiment the drift tube is splii longitudinally into quadrants supported along the axis of the accelerator by webs from a yoke, the quadrants. webs, and yoke being of magnetic material. A magnetic focusing action is produced by energizing a winding on each web to set up a magnetic field between adjacent quadrants. In the other embodiment the quadrants are electrically insulated from each other and have opposite polarity voltages on adjacent quadrants to provide an electric focusing fleld for the particles, with the quadrants spaced sufficienily close enough to shield the particles within the tube from the accelerating electric field.

  19. LINEAR ACCELERATOR

    DOEpatents

    Christofilos, N.C.; Polk, I.J.

    1959-02-17

    Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.

  20. Statins and cerebral hemodynamics

    PubMed Central

    Giannopoulos, Sotirios; Katsanos, Aristeidis H; Tsivgoulis, Georgios; Marshall, Randolph S

    2012-01-01

    HMG-CoA reductase inhibitors (statins) are associated with improved stroke outcome. This observation has been attributed in part to the palliative effect of statins on cerebral hemodynamics and cerebral autoregulation (CA), which are mediated mainly through the upregulation of endothelium nitric oxide synthase (eNOS). Several animal studies indicate that statin pretreatment enhances cerebral blood flow after ischemic stroke, although this finding is not further supported in clinical settings. Cerebral vasomotor reactivity, however, is significantly improved after long-term statin administration in most patients with severe small vessel disease, aneurysmal subarachnoid hemorrhage, or impaired baseline CA. PMID:22929438

  1. Variants in CUL4B are Associated with Cerebral Malformations

    PubMed Central

    Vulto-van Silfhout, Anneke T.; Nakagawa, Tadashi; Bahi-Buisson, Nadia; Haas, Stefan A.; Hu, Hao; Bienek, Melanie; Vissers, Lisenka E.L.M.; Gilissen, Christian; Tzschach, Andreas; Busche, Andreas; Müsebeck, Jörg; Rump, Patrick; Mathijssen, Inge B.; Avela, Kristiina; Somer, Mirja; Doagu, Fatma; Philips, Anju K.; Rauch, Anita; Baumer, Alessandra; Voesenek, Krysta; Poirier, Karine; Vigneron, Jacqueline; Amram, Daniel; Odent, Sylvie; Nawara, Magdalena; Obersztyn, Ewa; Lenart, Jacek; Charzewska, Agnieszka; Lebrun, Nicolas; Fischer, Ute; Nillesen, Willy M.; Yntema, Helger G.; Järvelä, Irma; Ropers, Hans-Hilger; de Vries, Bert B.A.; Brunner, Han G.; van Bokhoven, Hans; Raymond, F. Lucy; Willemsen, Michèl A.A.P.; Chelly, Jamel; Xiong, Yue; Barkovich, A. James; Kalscheuer, Vera M.; Kleefstra, Tjitske; de Brouwer, Arjan P.M.

    2015-01-01

    Variants in cullin 4B (CUL4B) are a known cause of syndromic X-linked intellectual disability. Here, we describe an additional 25 patients from 11 families with variants in CUL4B. We identified nine different novel variants in these families and confirmed the pathogenicity of all nontruncating variants. Neuroimaging data, available for 15 patients, showed the presence of cerebral malformations in ten patients. The cerebral anomalies comprised malformations of cortical development (MCD), ventriculomegaly, and diminished white matter volume. The phenotypic heterogeneity of the cerebral malformations might result from the involvement of CUL-4B in various cellular pathways essential for normal brain development. Accordingly, we show that CUL-4B interacts with WDR62, a protein in which variants were previously identified in patients with microcephaly and a wide range of MCD. This interaction might contribute to the development of cerebral malformations in patients with variants in CUL4B. PMID:25385192

  2. Variants in CUL4B are associated with cerebral malformations.

    PubMed

    Vulto-van Silfhout, Anneke T; Nakagawa, Tadashi; Bahi-Buisson, Nadia; Haas, Stefan A; Hu, Hao; Bienek, Melanie; Vissers, Lisenka E L M; Gilissen, Christian; Tzschach, Andreas; Busche, Andreas; Müsebeck, Jörg; Rump, Patrick; Mathijssen, Inge B; Avela, Kristiina; Somer, Mirja; Doagu, Fatma; Philips, Anju K; Rauch, Anita; Baumer, Alessandra; Voesenek, Krysta; Poirier, Karine; Vigneron, Jacqueline; Amram, Daniel; Odent, Sylvie; Nawara, Magdalena; Obersztyn, Ewa; Lenart, Jacek; Charzewska, Agnieszka; Lebrun, Nicolas; Fischer, Ute; Nillesen, Willy M; Yntema, Helger G; Järvelä, Irma; Ropers, Hans-Hilger; de Vries, Bert B A; Brunner, Han G; van Bokhoven, Hans; Raymond, F Lucy; Willemsen, Michèl A A P; Chelly, Jamel; Xiong, Yue; Barkovich, A James; Kalscheuer, Vera M; Kleefstra, Tjitske; de Brouwer, Arjan P M

    2015-01-01

    Variants in cullin 4B (CUL4B) are a known cause of syndromic X-linked intellectual disability. Here, we describe an additional 25 patients from 11 families with variants in CUL4B. We identified nine different novel variants in these families and confirmed the pathogenicity of all nontruncating variants. Neuroimaging data, available for 15 patients, showed the presence of cerebral malformations in ten patients. The cerebral anomalies comprised malformations of cortical development (MCD), ventriculomegaly, and diminished white matter volume. The phenotypic heterogeneity of the cerebral malformations might result from the involvement of CUL-4B in various cellular pathways essential for normal brain development. Accordingly, we show that CUL-4B interacts with WDR62, a protein in which variants were previously identified in patients with microcephaly and a wide range of MCD. This interaction might contribute to the development of cerebral malformations in patients with variants in CUL4B.

  3. Cerebral Asymmetries and Reading Acquisition

    ERIC Educational Resources Information Center

    Pirozzolo, Francis J.

    1978-01-01

    Reviewed are historical developments regarding the concepts of cerebral localization, and analyzed are implications of current research on the role of the cerebral hemispheres in reading disorders. (CL)

  4. Cerebral Small Vessel Disease: Targeting Oxidative Stress as a Novel Therapeutic Strategy?

    PubMed Central

    De Silva, T. Michael; Miller, Alyson A.

    2016-01-01

    Cerebral small vessel disease (SVD) is a major contributor to stroke, and a leading cause of cognitive impairment and dementia. Despite the devastating effects of cerebral SVD, the pathogenesis of cerebral SVD is still not completely understood. Moreover, there are no specific pharmacological strategies for its prevention or treatment. Cerebral SVD is characterized by marked functional and structural abnormalities of the cerebral microcirculation. The clinical manifestations of these pathological changes include lacunar infarcts, white matter hyperintensities, and cerebral microbleeds. The main purpose of this review is to discuss evidence implicating oxidative stress in the arteriopathy of both non-amyloid and amyloid (cerebral amyloid angiopathy) forms of cerebral SVD and its most important risk factors (hypertension and aging), as well as its contribution to cerebral SVD-related brain injury and cognitive impairment. We also highlight current evidence of the involvement of the NADPH oxidases in the development of oxidative stress, enzymes that are a major source of reactive oxygen species in the cerebral vasculature. Lastly, we discuss potential pharmacological strategies for oxidative stress in cerebral SVD, including some of the historical and emerging NADPH oxidase inhibitors. PMID:27014073

  5. Cerebral Palsy (CP) Quiz

    MedlinePlus

    ... Submit Button Past Emails CDC Features Pop Quiz: Cerebral Palsy Language: English Español (Spanish) Recommend on Facebook Tweet ... Sandy is the parent of a child with cerebral palsy and the Board President of Gio’s Garden , a ...

  6. Development of white matter and reading skills.

    PubMed

    Yeatman, Jason D; Dougherty, Robert F; Ben-Shachar, Michal; Wandell, Brian A

    2012-10-30

    White matter tissue properties are highly correlated with reading proficiency; we would like to have a model that relates the dynamics of an individual's white matter development to their acquisition of skilled reading. The development of cerebral white matter involves multiple biological processes, and the balance between these processes differs between individuals. Cross-sectional measures of white matter mask the interplay between these processes and their connection to an individual's cognitive development. Hence, we performed a longitudinal study to measure white-matter development (diffusion-weighted imaging) and reading development (behavioral testing) in individual children (age 7-15 y). The pattern of white-matter development differed significantly among children. In the left arcuate and left inferior longitudinal fasciculus, children with above-average reading skills initially had low fractional anisotropy (FA) that increased over the 3-y period, whereas children with below-average reading skills had higher initial FA that declined over time. We describe a dual-process model of white matter development comprising biological processes with opposing effects on FA, such as axonal myelination and pruning, to explain the pattern of results.

  7. Acceleration Studies

    NASA Technical Reports Server (NTRS)

    Rogers, Melissa J. B.

    1993-01-01

    Work to support the NASA MSFC Acceleration Characterization and Analysis Project (ACAP) was performed. Four tasks (analysis development, analysis research, analysis documentation, and acceleration analysis) were addressed by parallel projects. Work concentrated on preparation for and implementation of near real-time SAMS data analysis during the USMP-1 mission. User support documents and case specific software documentation and tutorials were developed. Information and results were presented to microgravity users. ACAP computer facilities need to be fully implemented and networked, data resources must be cataloged and accessible, future microgravity missions must be coordinated, and continued Orbiter characterization is necessary.

  8. Particle acceleration

    NASA Technical Reports Server (NTRS)

    Vlahos, L.; Machado, M. E.; Ramaty, R.; Murphy, R. J.; Alissandrakis, C.; Bai, T.; Batchelor, D.; Benz, A. O.; Chupp, E.; Ellison, D.

    1986-01-01

    Data is compiled from Solar Maximum Mission and Hinothori satellites, particle detectors in several satellites, ground based instruments, and balloon flights in order to answer fundamental questions relating to: (1) the requirements for the coronal magnetic field structure in the vicinity of the energization source; (2) the height (above the photosphere) of the energization source; (3) the time of energization; (4) transistion between coronal heating and flares; (5) evidence for purely thermal, purely nonthermal and hybrid type flares; (6) the time characteristics of the energization source; (7) whether every flare accelerates protons; (8) the location of the interaction site of the ions and relativistic electrons; (9) the energy spectra for ions and relativistic electrons; (10) the relationship between particles at the Sun and interplanetary space; (11) evidence for more than one acceleration mechanism; (12) whether there is single mechanism that will accelerate particles to all energies and also heat the plasma; and (13) how fast the existing mechanisms accelerate electrons up to several MeV and ions to 1 GeV.

  9. Plasma accelerator

    DOEpatents

    Wang, Zhehui; Barnes, Cris W.

    2002-01-01

    There has been invented an apparatus for acceleration of a plasma having coaxially positioned, constant diameter, cylindrical electrodes which are modified to converge (for a positive polarity inner electrode and a negatively charged outer electrode) at the plasma output end of the annulus between the electrodes to achieve improved particle flux per unit of power.

  10. Accelerated Achievement

    ERIC Educational Resources Information Center

    Ford, William J.

    2010-01-01

    This article focuses on the accelerated associate degree program at Ivy Tech Community College (Indiana) in which low-income students will receive an associate degree in one year. The three-year pilot program is funded by a $2.3 million grant from the Lumina Foundation for Education in Indianapolis and a $270,000 grant from the Indiana Commission…

  11. ACCELERATION INTEGRATOR

    DOEpatents

    Pope, K.E.

    1958-01-01

    This patent relates to an improved acceleration integrator and more particularly to apparatus of this nature which is gyrostabilized. The device may be used to sense the attainment by an airborne vehicle of a predetermined velocitv or distance along a given vector path. In its broad aspects, the acceleration integrator utilizes a magnetized element rotatable driven by a synchronous motor and having a cylin drical flux gap and a restrained eddy- current drag cap deposed to move into the gap. The angular velocity imparted to the rotatable cap shaft is transmitted in a positive manner to the magnetized element through a servo feedback loop. The resultant angular velocity of tae cap is proportional to the acceleration of the housing in this manner and means may be used to measure the velocity and operate switches at a pre-set magnitude. To make the above-described dcvice sensitive to acceleration in only one direction the magnetized element forms the spinning inertia element of a free gyroscope, and the outer housing functions as a gimbal of a gyroscope.

  12. [Tomographic analysis of CBF in cerebral infarction].

    PubMed

    Segawa, H; Kimura, K; Ueda, Y; Nagai, M; Yoshimasu, N; Nakagomi, T; Tamura, A; Sano, K; Takakura, K

    1983-06-01

    Cerebral perfusion was examined in various types of occlusive disease by computed tomographic CBF method. The method utilized has several advantages over conventional studies using isotope, providing high resolution images in a direct relation to CT anatomy. Ten representative cases were presented from 25 consecutive cases of occlusive disease studied by this method. The method included inhalation of 40 to 60% xenon with serial CT scanning for 25 min. K (build-up rate), lambda (partition coefficient) and CBF values were calculated from HU for each pixel and Xe in expired air, based on Fick's principle, and displayed on CRT as K-, lambda- and CBF-map separately. CBF for gray matter of normal control was 82 +/- 11 ml/100 gm/min and that for white matter was 24 +/- 5 ml/100 gm/min. The ischemic threshold for gray matter appeared to be approximately 20 ml/100 gm/min, as blood flow in focus of complete infarction was below this level. Blood flow between 20-30 ml/100 gm/min caused some change on CT, such as localized atrophy, cortical thinning, loss of distinction between gray and white matter and decreased or increased density, which were considered to be compatible with pathological changes of laminar necrosis or gliosis with neuronal loss. In a case with occlusion of middle cerebral artery with subsequent recanalization, causing hemorrhagic infarct, hyperemia was observed in the infarcted cortex that was enhanced by iodine. Periventricular lucency observed in two cases, where blood flow was decreased below threshold, could be classified as "watershed infarction" mainly involving white matter. In moyamoya disease, blood flow in the anterior circulation was decreased near ischemic level, whereas that in basal ganglia and territory of posterior cerebral artery was fairly preserved, which was compatible with general angiographic finding of this disease.

  13. Perinatal White Matter Injury: The Changing Spectrum of Pathology and Emerging Insights into Pathogenetic Mechanisms

    ERIC Educational Resources Information Center

    Back, Stephen A.

    2006-01-01

    Perinatal brain injury in survivors of premature birth has a unique and unexplained predilection for periventricular cerebral white matter. Periventricular white-matter injury (PWMI) is now the most common cause of brain injury in preterm infants and the leading cause of chronic neurological morbidity. The spectrum of chronic PWMI includes focal…

  14. Particle Accelerators in China

    NASA Astrophysics Data System (ADS)

    Zhang, Chuang; Fang, Shouxian

    As the special machines that can accelerate charged particle beams to high energy by using electromagnetic fields, particle accelerators have been widely applied in scientific research and various areas of society. The development of particle accelerators in China started in the early 1950s. After a brief review of the history of accelerators, this article describes in the following sections: particle colliders, heavy-ion accelerators, high-intensity proton accelerators, accelerator-based light sources, pulsed power accelerators, small scale accelerators, accelerators for applications, accelerator technology development and advanced accelerator concepts. The prospects of particle accelerators in China are also presented.

  15. White Blood Cell Count

    MedlinePlus

    ... limited. Home Visit Global Sites Search Help? White Blood Cell Count Share this page: Was this page helpful? ... Count; Leukocyte Count; White Count Formal name: White Blood Cell Count Related tests: Complete Blood Count , Blood Smear , ...

  16. Compact accelerator

    DOEpatents

    Caporaso, George J.; Sampayan, Stephen E.; Kirbie, Hugh C.

    2007-02-06

    A compact linear accelerator having at least one strip-shaped Blumlein module which guides a propagating wavefront between first and second ends and controls the output pulse at the second end. Each Blumlein module has first, second, and third planar conductor strips, with a first dielectric strip between the first and second conductor strips, and a second dielectric strip between the second and third conductor strips. Additionally, the compact linear accelerator includes a high voltage power supply connected to charge the second conductor strip to a high potential, and a switch for switching the high potential in the second conductor strip to at least one of the first and third conductor strips so as to initiate a propagating reverse polarity wavefront(s) in the corresponding dielectric strip(s).

  17. Laser acceleration

    NASA Astrophysics Data System (ADS)

    Tajima, T.; Nakajima, K.; Mourou, G.

    2017-02-01

    The fundamental idea of Laser Wakefield Acceleration (LWFA) is reviewed. An ultrafast intense laser pulse drives coherent wakefield with a relativistic amplitude robustly supported by the plasma. While the large amplitude of wakefields involves collective resonant oscillations of the eigenmode of the entire plasma electrons, the wake phase velocity ˜ c and ultrafastness of the laser pulse introduce the wake stability and rigidity. A large number of worldwide experiments show a rapid progress of this concept realization toward both the high-energy accelerator prospect and broad applications. The strong interest in this has been spurring and stimulating novel laser technologies, including the Chirped Pulse Amplification, the Thin Film Compression, the Coherent Amplification Network, and the Relativistic Mirror Compression. These in turn have created a conglomerate of novel science and technology with LWFA to form a new genre of high field science with many parameters of merit in this field increasing exponentially lately. This science has triggered a number of worldwide research centers and initiatives. Associated physics of ion acceleration, X-ray generation, and astrophysical processes of ultrahigh energy cosmic rays are reviewed. Applications such as X-ray free electron laser, cancer therapy, and radioisotope production etc. are considered. A new avenue of LWFA using nanomaterials is also emerging.

  18. BICEP's acceleration

    SciTech Connect

    Contaldi, Carlo R.

    2014-10-01

    The recent Bicep2 [1] detection of, what is claimed to be primordial B-modes, opens up the possibility of constraining not only the energy scale of inflation but also the detailed acceleration history that occurred during inflation. In turn this can be used to determine the shape of the inflaton potential V(φ) for the first time — if a single, scalar inflaton is assumed to be driving the acceleration. We carry out a Monte Carlo exploration of inflationary trajectories given the current data. Using this method we obtain a posterior distribution of possible acceleration profiles ε(N) as a function of e-fold N and derived posterior distributions of the primordial power spectrum P(k) and potential V(φ). We find that the Bicep2 result, in combination with Planck measurements of total intensity Cosmic Microwave Background (CMB) anisotropies, induces a significant feature in the scalar primordial spectrum at scales k∼ 10{sup -3} Mpc {sup -1}. This is in agreement with a previous detection of a suppression in the scalar power [2].

  19. Cerebral Palsy (For Parents)

    MedlinePlus

    ... palsy — causes a problem with balance and depth perception Since cerebral palsy affects muscle control and coordination, ... fluid into the lungs) gastroesophageal reflux (spitting up) speech problems drooling tooth decay sleep disorders osteoporosis (weak, ...

  20. Cerebral Contusions and Lacerations

    MedlinePlus

    ... Sports-Related Concussion Diffuse Axonal Injury Intracranial Hematomas Skull Fracture Cerebral contusions are bruises of the brain, ... object or pushed-in bone fragment from a skull fracture. Motor vehicle crashes and blows to the ...

  1. Cerebral amyloid angiopathy

    MedlinePlus

    ... 911) if you have sudden loss of movement , sensation, vision, or speech. Alternative Names Amyloidosis - cerebral; CAA; Congophilic angiopathy Images Amyloidosis on the fingers Arteries of the brain References Kase CS, Shoamanesh A. Intracerebral hemorrhage. In: Daroff ...

  2. White Horse Program review, FY 82

    SciTech Connect

    Dogliani, H.O.; Farrell, J.A.

    1983-09-01

    A review of major achievements in the White Horse Program is provided. Most efforts in FY 82 involved completion of the 2-MeV accelerator test stand culminating in installation of the RFQ, on-line in September 1982. Numerous experiments were conducted, resulting in a significant understanding of beam dynamics and rf structures.

  3. Cerebral Amyloid Angiopathy: Emerging Concepts

    PubMed Central

    2015-01-01

    Cerebral amyloid angiopathy (CAA) involves cerebrovascular amyloid deposition and is classified into several types according to the amyloid protein involved. Of these, sporadic amyloid β-protein (Aβ)-type CAA is most commonly found in older individuals and in patients with Alzheimer's disease (AD). Cerebrovascular Aβ deposits accompany functional and pathological changes in cerebral blood vessels (CAA-associated vasculopathies). CAA-associated vasculopathies lead to development of hemorrhagic lesions [lobar intracerebral macrohemorrhage, cortical microhemorrhage, and cortical superficial siderosis (cSS)/focal convexity subarachnoid hemorrhage (SAH)], ischemic lesions (cortical infarction and ischemic changes of the white matter), and encephalopathies that include subacute leukoencephalopathy caused by CAA-associated inflammation/angiitis. Thus, CAA is related to dementia, stroke, and encephalopathies. Recent advances in diagnostic procedures, particularly neuroimaging, have enabled us to establish a clinical diagnosis of CAA without brain biopsies. Sensitive magnetic resonance imaging (MRI) methods, such as gradient-echo T2* imaging and susceptibility-weighted imaging, are useful for detecting cortical microhemorrhages and cSS. Amyloid imaging with amyloid-binding positron emission tomography (PET) ligands, such as Pittsburgh Compound B, can detect CAA, although they cannot discriminate vascular from parenchymal amyloid deposits. In addition, cerebrospinal fluid markers may be useful, including levels of Aβ40 for CAA and anti-Aβ antibody for CAA-related inflammation. Moreover, cSS is closely associated with transient focal neurological episodes (TFNE). CAA-related inflammation/angiitis shares pathophysiology with amyloid-related imaging abnormalities (ARIA) induced by Aβ immunotherapies in AD patients. This article reviews CAA and CAA-related disorders with respect to their epidemiology, pathology, pathophysiology, clinical features, biomarkers, diagnosis

  4. Nanomedicine in cerebral palsy.

    PubMed

    Balakrishnan, Bindu; Nance, Elizabeth; Johnston, Michael V; Kannan, Rangaramanujam; Kannan, Sujatha

    2013-01-01

    Cerebral palsy is a chronic childhood disorder that can have diverse etiologies. Injury to the developing brain that occurs either in utero or soon after birth can result in the motor, sensory, and cognitive deficits seen in cerebral palsy. Although the etiologies for cerebral palsy are variable, neuroinflammation plays a key role in the pathophysiology of the brain injury irrespective of the etiology. Currently, there is no effective cure for cerebral palsy. Nanomedicine offers a new frontier in the development of therapies for prevention and treatment of brain injury resulting in cerebral palsy. Nanomaterials such as dendrimers provide opportunities for the targeted delivery of multiple drugs that can mitigate several pathways involved in injury and can be delivered specifically to the cells that are responsible for neuroinflammation and injury. These materials also offer the opportunity to deliver agents that would promote repair and regeneration in the brain, resulting not only in attenuation of injury, but also enabling normal growth. In this review, the current advances in nanotechnology for treatment of brain injury are discussed with specific relevance to cerebral palsy. Future directions that would facilitate clinical translation in neonates and children are also addressed.

  5. Advanced concepts for acceleration

    SciTech Connect

    Keefe, D.

    1986-07-01

    Selected examples of advanced accelerator concepts are reviewed. Such plasma accelerators as plasma beat wave accelerator, plasma wake field accelerator, and plasma grating accelerator are discussed particularly as examples of concepts for accelerating relativistic electrons or positrons. Also covered are the pulsed electron-beam, pulsed laser accelerator, inverse Cherenkov accelerator, inverse free-electron laser, switched radial-line accelerators, and two-beam accelerator. Advanced concepts for ion acceleration discussed include the electron ring accelerator, excitation of waves on intense electron beams, and two-wave combinations. (LEW)

  6. Accelerators and the Accelerator Community

    SciTech Connect

    Malamud, Ernest; Sessler, Andrew

    2008-06-01

    In this paper, standing back--looking from afar--and adopting a historical perspective, the field of accelerator science is examined. How it grew, what are the forces that made it what it is, where it is now, and what it is likely to be in the future are the subjects explored. Clearly, a great deal of personal opinion is invoked in this process.

  7. Differential impact of serum total bilirubin level on cerebral atherosclerosis and cerebral small vessel disease

    PubMed Central

    Kim, Jonguk; Yoon, Seung-Jae; Woo, Min-Hee; Kim, Sang-Heum; Kim, Nam-Keun; Kim, Jinkwon; Kim, OK-Joon; Oh, Seung-Hun

    2017-01-01

    Background A low serum total bilirubin (T-bil) level is associated with an increased risk of atherosclerosis. However, the differential impact of the serum T-bil level on cerebral atherosclerosis and cerebral small vessel disease (SVD) is still unclear. Methods We evaluated serum T-bil levels from 1,128 neurologically healthy subjects. Indices of cerebral atherosclerosis (extracranial arterial stenosis [ECAS] and intracranial arterial stenosis [ICAS]), and indices of SVD (silent lacunar infarct [SLI], and moderate-to-severe white matter hyperintensities [msWMH]) were evaluated by the use of brain magnetic resonance imaging (MRI) and MR angiography. Results In logistic regression analysis after adjusting for confounding variables, subjects within middle T-bil (odds ratio [OR]: 0.63; 95% CI: 0.41–0.97) and high T-bil tertiles (OR: 0.54; 95% CI: 0.33–0.86) showed a lower prevalence of ECAS than those in a low T-bil tertile. Although subjects with a high T-bil tertile had a lower prevalence of ICAS than those with a low T-bil tertile, the statistical significance was marginal after adjusting for confounding variables. There were no significant differences in the proportions of subjects with SLI and msWMH across serum T-bil tertile groups. Conclusions The serum T-bil level is negatively associated with cerebral atherosclerosis, especially extracranial atherosclerosis, but not with SVD. PMID:28319156

  8. Acceleration-selective arterial spin labeling.

    PubMed

    Schmid, Sophie; Ghariq, Eidrees; Teeuwisse, Wouter M; Webb, Andrew; van Osch, Matthias J P

    2014-01-01

    In this study, a new arterial spin labeling (ASL) method with spatially nonselective labeling is introduced, based on the acceleration of flowing spins, which is able to image brain perfusion with minimal contamination from venous signal. This method is termed acceleration-selective ASL (AccASL) and resembles velocity-selective ASL (VSASL), with the difference that AccASL is able to discriminate between arterial and venous components in a single preparation module due to the higher acceleration on the arterial side of the microvasculature, whereas VSASL cannot make this distinction unless a second labeling module is used. A difference between AccASL and VSASL is that AccASL is mainly cerebral blood volume weighted, whereas VSASL is cerebral blood flow weighted. AccASL exploits the principles of acceleration-encoded magnetic resonance angiography by using motion-sensitizing gradients in a T2 -preparation module. This method is demonstrated in healthy volunteers for a range of cutoff accelerations. Additionally, AccASL is compared with VSASL and pseudo-continuous ASL, and its feasibility in functional MRI is demonstrated. Compared with VSASL with a single labeling module, a strong and significant reduction in venous label is observed. The resulting signal-to-noise ratio is comparable to pseudo-continuous ASL and robust activation of the visual cortex is observed.

  9. The human cerebral cortex flattens during adolescence.

    PubMed

    Alemán-Gómez, Yasser; Janssen, Joost; Schnack, Hugo; Balaban, Evan; Pina-Camacho, Laura; Alfaro-Almagro, Fidel; Castro-Fornieles, Josefina; Otero, Soraya; Baeza, Immaculada; Moreno, Dolores; Bargalló, Nuria; Parellada, Mara; Arango, Celso; Desco, Manuel

    2013-09-18

    The human cerebral cortex appears to shrink during adolescence. To delineate the dynamic morphological changes involved in this process, 52 healthy male and female adolescents (11-17 years old) were neuroimaged twice using magnetic resonance imaging, approximately 2 years apart. Using a novel morphometric analysis procedure combining the FreeSurfer and BrainVisa image software suites, we quantified global and lobar change in cortical thickness, outer surface area, the gyrification index, the average Euclidean distance between opposing sides of the white matter surface (gyral white matter thickness), the convex ("exposed") part of the outer cortical surface (hull surface area), sulcal length, depth, and width. We found that the cortical surface flattens during adolescence. Flattening was strongest in the frontal and occipital cortices, in which significant sulcal widening and decreased sulcal depth co-occurred. Globally, sulcal widening was associated with cortical thinning and, for the frontal cortex, with loss of surface area. For the other cortical lobes, thinning was related to gyral white matter expansion. The overall flattening of the macrostructural three-dimensional architecture of the human cortex during adolescence thus involves changes in gray matter and effects of the maturation of white matter.

  10. Impact accelerations

    NASA Technical Reports Server (NTRS)

    Vongierke, H. E.; Brinkley, J. W.

    1975-01-01

    The degree to which impact acceleration is an important factor in space flight environments depends primarily upon the technology of capsule landing deceleration and the weight permissible for the associated hardware: parachutes or deceleration rockets, inflatable air bags, or other impact attenuation systems. The problem most specific to space medicine is the potential change of impact tolerance due to reduced bone mass and muscle strength caused by prolonged weightlessness and physical inactivity. Impact hazards, tolerance limits, and human impact tolerance related to space missions are described.

  11. Focal cerebral mantle disruption in fetal hydrocephalus.

    PubMed

    Humphreys, Peter; Muzumdar, Dattatraya P; Sly, Lloyd E; Michaud, Jean

    2007-04-01

    A variety of developmental brain anomalies have been described in individuals with fetal hydrocephalus, regardless of etiology. Examples include callosal dysgenesis, periventricular gray matter heterotopia, hippocampal and white matter hypoplasia, and cortical polygyration. The present report draws attention to another anomaly not reported in previous case series of fetal hydrocephalus: focal cerebral mantle disruption. Neonatal imaging findings (where available) and post-shunt, stable-state magnetic resonance imaging, or pathological findings were reviewed in 77 subjects with fetal hydrocephalus (55 myelomeningocele, 16 sporadic aqueductal stenosis, 6 miscellaneous). Of these, 12 subjects (15.6%) demonstrated a combination of absence of the septum pellucidum and severe thinning or absence of the posteromesial cerebral mantle. On axial sequences, this combination created the illusion of a common ventricle, as in lobar holoprosencephaly. All 12 subjects had massive hydrocephalus at birth, accompanied in 7 by posteromesial ventricular diverticula. Two subjects, and one other subject with distinct lateral ventricles, demonstrated unilateral or bilateral mantle clefts suggestive of schizencephaly. Close radiological (n = 2) or pathological (n = 1) inspection showed that the clefts were only partially lined with gray matter and contained a transverse gliotic membrane. These findings are consistent with the hypothesis that massive early fetal hydrocephalus may completely disrupt cerebral mantle formation, particularly in the posteromesial hemispheres.

  12. Ischemic brain injury in cerebral amyloid angiopathy

    PubMed Central

    van Veluw, Susanne J; Greenberg, Steven M

    2016-01-01

    Cerebral amyloid angiopathy (CAA) is a common form of cerebral small vessel disease and an important risk factor for intracerebral hemorrhage and cognitive impairment. While the majority of research has focused on the hemorrhagic manifestation of CAA, its ischemic manifestations appear to have substantial clinical relevance as well. Findings from imaging and pathologic studies indicate that ischemic lesions are common in CAA, including white-matter hyperintensities, microinfarcts, and microstructural tissue abnormalities as detected with diffusion tensor imaging. Furthermore, imaging markers of ischemic disease show a robust association with cognition, independent of age, hemorrhagic lesions, and traditional vascular risk factors. Widespread ischemic tissue injury may affect cognition by disrupting white-matter connectivity, thereby hampering communication between brain regions. Challenges are to identify imaging markers that are able to capture widespread microvascular lesion burden in vivo and to further unravel the etiology of ischemic tissue injury by linking structural magnetic resonance imaging (MRI) abnormalities to their underlying pathophysiology and histopathology. A better understanding of the underlying mechanisms of ischemic brain injury in CAA will be a key step toward new interventions to improve long-term cognitive outcomes for patients with CAA. PMID:25944592

  13. White Men's Racial Others

    ERIC Educational Resources Information Center

    Lensmire, Timothy J.

    2014-01-01

    Background/Context: Increasingly, researchers and educators have argued that alternative conceptions of Whiteness and White racial identity are needed because current conceptions have undermined, rather than strengthened, our critical pedagogies with White people. Grounded in critical Whiteness studies, and drawing especially on the writings of…

  14. Reversible cerebral shrinkage in kwashiorkor: an MRI study.

    PubMed

    Gunston, G D; Burkimsher, D; Malan, H; Sive, A A

    1992-08-01

    Protein energy malnutrition is associated with cerebral atrophy which may be detrimental to intellectual development. The aim of this study was to document the anatomical abnormalities which lead to the appearance of cerebral atrophy using magnetic resonance imaging (MRI) in the acute stage of kwashiorkor and to monitor changes during nutritional rehabilitation. Twelve children aged 6 to 37 months requiring admission to hospital for the treatment of kwashiorkor were studied. The children were evaluated clinically, biochemically, and by MRI of their brains on admission and 30 and 90 days later. Brain shrinkage was present in every child on admission. White and grey matter appeared equally affected and the myelination was normal for age. At 90 days, the cerebral changes had resolved in nine and improved substantially in the remainder, by which time serum proteins and weight for age were within the normal range. The findings of this study suggest that brain shrinkage associated with kwashiorkor reverses rapidly with nutritional rehabilitation.

  15. Contrast-enhanced imaging of cerebral vasculature with laser speckle

    NASA Astrophysics Data System (ADS)

    Murari, K.; Li, N.; Rege, A.; Jia, X.; All, A.; Thakor, N.

    2007-08-01

    High-resolution cerebral vasculature imaging has applications ranging from intraoperative procedures to basic neuroscience research. Laser speckle, with spatial contrast processing, has recently been used to map cerebral blood flow. We present an application of the technique using temporal contrast processing to image cerebral vascular structures with a field of view a few millimeters across and approximately 20 μm resolution through a thinned skull. We validate the images using fluorescent imaging and demonstrate a factor of 2-4 enhancement in contrast-to-noise ratios over reflectance imaging using white or spectrally filtered green light. The contrast enhancement enables the perception of approximately 10%-30% more vascular structures without the introduction of any contrast agent.

  16. A Dietary Treatment Improves Cerebral Blood Flow and Brain Connectivity in Aging apoE4 Mice

    PubMed Central

    Wiesmann, Maximilian; Zerbi, Valerio; Jansen, Diane; Haast, Roy; Lütjohann, Dieter; Broersen, Laus M.; Heerschap, Arend

    2016-01-01

    APOE ε4 (apoE4) polymorphism is the main genetic determinant of sporadic Alzheimer's disease (AD). A dietary approach (Fortasyn) including docosahexaenoic acid, eicosapentaenoic acid, uridine, choline, phospholipids, folic acid, vitamins B12, B6, C, and E, and selenium has been proposed for dietary management of AD. We hypothesize that the diet could inhibit AD-like pathologies in apoE4 mice, specifically cerebrovascular and connectivity impairment. Moreover, we evaluated the diet effect on cerebral blood flow (CBF), functional connectivity (FC), gray/white matter integrity, and postsynaptic density in aging apoE4 mice. At 10–12 months, apoE4 mice did not display prominent pathological differences compared to wild-type (WT) mice. However, 16–18-month-old apoE4 mice revealed reduced CBF and accelerated synaptic loss. The diet increased cortical CBF and amount of synapses and improved white matter integrity and FC in both aging apoE4 and WT mice. We demonstrated that protective mechanisms on vascular and synapse health are enhanced by Fortasyn, independent of apoE genotype. We further showed the efficacy of a multimodal translational approach, including advanced MR neuroimaging, to study dietary intervention on brain structure and function in aging. PMID:27034849

  17. OLIGODENDROCYTE DEGENERATION AND RECOVERY AFTER FOCAL CEREBRAL ISCHEMIA

    PubMed Central

    McIver, Sally R.; Muccigrosso, Megan; Gonzales, Ernesto R.; Lee, Jin-Moo; Roberts, Marie S.; Sands, Mark S.; Goldberg, Mark P.

    2013-01-01

    The vulnerability of oligodendrocytes to ischemic injury may contribute to functional loss in diseases of central white matter. Immunocytochemical methods to identify oligodendrocyte injury in experimental models rely on epitope availability, and fail to discriminate structural changes in oligodendrocyte morphology. We previously described the use of a lentiviral vector (LV) carrying eGFP under the myelin basic protein (MBP) promoter for selective visualization of oligodendrocyte cell bodies and processes. In this study, we used LV-MBP-eGFP to label oligodendrocytes in rat cerebral white matter prior to transient focal cerebral ischemia, and examined oligodendrocyte injury 24 hours, 48 hours and one week post-reperfusion by quantifying cell survival and assaying the integrity of myelin processes. There was progressive loss of GFP+ oligodendrocytes in ischemic white matter at 24 and 48 hrs. Surviving GFP+ cells had non-pyknotic nuclear morphology and were TUNEL-negative, but there was marked fragmentation of myelin processes as early as 24 hours after stroke. One week after stroke, we observed a restoration of GFP+ oligodendrocytes in ischemic white matter, reflected both by cell counts and by structural integrity of myelin processes. Proliferating cells were not the main source of GFP+ oligodendrocytes, as revealed by BrdU incorporation. These observations identify novel transient structural changes in oligodendrocyte cell bodies and myelinating processes, which may have consequences for white matter function after stroke. PMID:20621643

  18. Accelerator system and method of accelerating particles

    NASA Technical Reports Server (NTRS)

    Wirz, Richard E. (Inventor)

    2010-01-01

    An accelerator system and method that utilize dust as the primary mass flux for generating thrust are provided. The accelerator system can include an accelerator capable of operating in a self-neutralizing mode and having a discharge chamber and at least one ionizer capable of charging dust particles. The system can also include a dust particle feeder that is capable of introducing the dust particles into the accelerator. By applying a pulsed positive and negative charge voltage to the accelerator, the charged dust particles can be accelerated thereby generating thrust and neutralizing the accelerator system.

  19. Catatonia After Cerebral Hypoxia: Do the Usual Treatments Apply?

    PubMed Central

    Quinn, Davin K.; Abbott, Christopher C.

    2014-01-01

    Introduction Neurologic deterioration occurring days to weeks after a cerebral hypoxic event accompanied by diffuse white matter demyelination is called delayed post-hypoxic leukoencephalopathy (DPHL). Manifestations of DPHL are diverse, and include dementia, gait disturbance, incontinence, pyramidal tract signs, parkinsonism, chorea, mood and thought disorders, akinetic mutism, and rarely catatonia. Methods The authors report a case of malignant catatonia in a patient diagnosed with DPHL that was refractory to electroconvulsive therapy (ECT), and review the literature on catatonia in DHPL. Results The patient was a 56 year-old female with schizoaffective disorder who was admitted with catatonia two weeks after hospitalization for drug overdose and respiratory failure. Her catatonic symptoms did not respond to lorazepam, amantadine, methylphenidate, or ten sessions of bilateral ECT at maximum energy. Repeat magnetic resonance imaging revealed extensive periventricular white matter lesions not present on admission scans, and she was diagnosed with DPHL. Discussion No treatment for DPHL has been proven to be widely effective. Hyperbaric oxygen treatments may reduce the rate of development, and symptom improvement has been reported with stimulants and other psychotropic agents. Review of the literature reveals rare success with GABAergic agents for catatonia after cerebral hypoxia, and no cases successfully treated with ECT. There are seven case reports of neurologic decompensation during ECT treatment after a cerebral hypoxic event. Conclusion Caution is advised when considering ECT for catatonia when delayed sequelae of cerebral hypoxia are on the differential diagnosis, as there is a dearth of evidence to support this treatment approach. PMID:25262046

  20. Brainstem Involvement as a Cause of Central Sleep Apnea: Pattern of Microstructural Cerebral Damage in Patients with Cerebral Microangiopathy

    PubMed Central

    Duning, Thomas; Deppe, Michael; Brand, Eva; Stypmann, Jörg; Becht, Charlotte; Heidbreder, Anna; Young, Peter

    2013-01-01

    Background The exact underlying pathomechanism of central sleep apnea with Cheyne-Stokes respiration (CSA-CSR) is still unclear. Recent studies have demonstrated an association between cerebral white matter changes and CSA. A dysfunction of central respiratory control centers in the brainstem was suggested by some authors. Novel MR-imaging analysis tools now allow far more subtle assessment of microstructural cerebral changes. The aim of this study was to investigate whether and what severity of subtle structural cerebral changes could lead to CSA-CSR, and whether there is a specific pattern of neurodegenerative changes that cause CSR. Therefore, we examined patients with Fabry disease (FD), an inherited, lysosomal storage disease. White matter lesions are early and frequent findings in FD. Thus, FD can serve as a "model disease" of cerebral microangiopathy to study in more detail the impact of cerebral lesions on central sleep apnea. Patients and Methods Genetically proven FD patients (n = 23) and age-matched healthy controls (n = 44) underwent a cardio-respiratory polysomnography and brain MRI at 3.0 Tesla. We applied different MR-imaging techniques, ranging from semiquantitative measurement of white matter lesion (WML) volumes and automated calculation of brain tissue volumes to VBM of gray matter and voxel-based diffusion tensor imaging (DTI) analysis. Results In 5 of 23 Fabry patients (22%) CSA-CSR was detected. Voxel-based DTI analysis revealed widespread structural changes in FD patients when compared to the healthy controls. When calculated as a separate group, DTI changes of CSA-CSR patients were most prominent in the brainstem. Voxel-based regression analysis revealed a significant association between CSR severity and microstructural DTI changes within the brainstem. Conclusion Subtle microstructural changes in the brainstem might be a neuroanatomical correlate of CSA-CSR in patients at risk of WML. DTI is more sensitive and specific than

  1. Biofidelic white matter heterogeneity decreases computational model predictions of white matter strains during rapid head rotations.

    PubMed

    Maltese, Matthew R; Margulies, Susan S

    2016-11-01

    The finite element (FE) brain model is used increasingly as a design tool for developing technology to mitigate traumatic brain injury. We developed an ultra high-definition FE brain model (>4 million elements) from CT and MRI scans of a 2-month-old pre-adolescent piglet brain, and simulated rapid head rotations. Strain distributions in the thalamus, coronal radiata, corpus callosum, cerebral cortex gray matter, brainstem and cerebellum were evaluated to determine the influence of employing homogeneous brain moduli, or distinct experimentally derived gray and white matter property representations, where some white matter regions are stiffer and others less stiff than gray matter. We find that constitutive heterogeneity significantly lowers white matter deformations in all regions compared with homogeneous properties, and should be incorporated in FE model injury prediction.

  2. Hypernatraemia in cerebral disorders

    PubMed Central

    Taylor, W. H.

    1962-01-01

    Six patients are described in whom cerebral damage was associated with raised plasma sodium and chloride concentrations and with extremely low urinary outputs of sodium and chloride. The patients were not clinically dehydrated and direct determinations showed that the blood and plasma volumes, the endogenous creatinine clearance, and the urinary output of antidiuretic hormone were normal. For these and other reasons it is concluded that the metabolic picture results not from diminished circulatory volume, water deficiency, sodium deficiency, undetected diabetes insipidus or osmotic diuresis, but from the cerebral damage itself. In these and other cited cases, the cerebral damage was localized chiefly in the frontal lobes, hypothalamus or lower brain-stem, thus suggesting a descending pathway, the relationship of which to the pineal area controlling aldosterone secretion requires clarification. Images PMID:13920001

  3. Duplicated middle cerebral artery.

    PubMed

    Perez, Jesus; Machado, Calixto; Scherle, Claudio; Hierro, Daniel

    2009-01-01

    Duplicated middle cerebral artery (DMCA) is an anomalous vessel arising from the internal carotid artery. The incidence DMCA is relatively law, and an association between this anomaly and cerebral aneurysms has been documented. There is a controversy whether DMCA may have perforating arteries. This is an important fact to consider in aneurysm surgery. We report the case of a 34-year-old black woman who suffered a subarachnoid hemorrhage and the angiography a left DMCA, and an aneurysm in an inferior branch of the main MCA. The DMCA and the MCA had perforating arteries. The aneurysm was clipped without complications. The observation of perforating arteries in our patient confirms that the DMCA may have perforating arteries. This is very important to be considered in cerebral aneurysms surgery. Moreover, the DMCA may potentially serve as a collateral blood supply to the MCA territory in cases of MCA occlusion.

  4. [Cerebral ischemia and histamine].

    PubMed

    Adachi, Naoto

    2002-10-01

    Cerebral ischemia induces excess release of glutamate and an increase in the intracellular Ca2+ concentration, which provoke catastrophic enzymatic processes leading to irreversible neuronal injury. Histamine plays the role of neurotransmitter in the central nervous system, and histaminergic fibers are widely distributed in the brain. In cerebral ischemia, release of histamine from nerve endings has been shown to be enhanced by facilitation of its activity. An inhibition of the histaminergic activity in ischemia aggravates the histologic outcome. In contrast, intracerebroventricular administration of histamine improves the aggravation, whereas blockade of histamine H2 receptors aggravates ischemic injury. Furthermore, H2 blockade enhances ischemic release of glutamate and dopamine. These findings suggest that central histamine provides beneficial effects against ischemic neuronal damage by suppressing release of excitatory neurotransmitters. However, histaminergic H2 action facilitates the permeability of the blood-brain barrier and shows deleterious effects on cerebral edema.

  5. AR Sco: A Precessing White Dwarf Synchronar?

    NASA Astrophysics Data System (ADS)

    Katz, J. I.

    2017-02-01

    The emission of the white dwarf–M dwarf binary AR Sco is driven by the rapid synchronization of its white dwarf, rather than by accretion. Synchronization requires a magnetic field ∼100 Gauss at the M dwarf and ∼ {10}8 Gauss at the white dwarf, larger than the fields of most intermediate polars but within the range of fields of known magnetic white dwarfs. The spindown power is dissipated in the atmosphere of the M dwarf, within the near zone of the rotating white dwarf’s field, by magnetic reconnection, accelerating particles that produce the observed synchrotron radiation. The displacement of the optical maximum from conjunction may be explained either by dissipation in a bow wave as the white dwarf’s magnetic field sweeps past the M dwarf or by a misaligned white dwarf rotation axis and oblique magnetic moment. In the latter case the rotation axis precesses with a period of decades, predicting a drift in the orbital phase of the optical maximum. Binaries whose emission is powered by synchronization may be termed synchronars, in analogy to magnetars.

  6. Cerebral venous sinus thrombosis with cerebral hemorrhage during early pregnancy

    PubMed Central

    Nie, Quanmin; Guo, Pin; Ge, Jianwei; Qiu, Yongming

    2015-01-01

    Cerebral venous sinus thrombosis (CVST) rarely induces cerebral hemorrhage, and CVST with cerebral hemorrhage during early pregnancy is extremely rare. Upon literature review, we are able to find only one case of CVST with cerebral hemorrhage in early pregnancy. In this paper, we report another case of a 27-year-old patient who developed CVST with cerebral hemorrhage in her fifth week of pregnancy. Although the optimal treatment for this infrequent condition remains controversial, we adopted anticoagulation as the first choice of treatment and obtained favorable results. PMID:25630781

  7. Acceleration modules in linear induction accelerators

    NASA Astrophysics Data System (ADS)

    Wang, Shao-Heng; Deng, Jian-Jun

    2014-05-01

    The Linear Induction Accelerator (LIA) is a unique type of accelerator that is capable of accelerating kilo-Ampere charged particle current to tens of MeV energy. The present development of LIA in MHz bursting mode and the successful application into a synchrotron have broadened LIA's usage scope. Although the transformer model is widely used to explain the acceleration mechanism of LIAs, it is not appropriate to consider the induction electric field as the field which accelerates charged particles for many modern LIAs. We have examined the transition of the magnetic cores' functions during the LIA acceleration modules' evolution, distinguished transformer type and transmission line type LIA acceleration modules, and re-considered several related issues based on transmission line type LIA acceleration module. This clarified understanding should help in the further development and design of LIA acceleration modules.

  8. Cerebral Small Vessel Disease and Chronic Kidney Disease

    PubMed Central

    2015-01-01

    Chronic kidney disease, defined by a decreased glomerular filtration rate or albuminuria, is recognized as a major global health burden, mainly because it is an established risk factor for cardiovascular and cerebrovascular diseases. The magnitude of the effect of chronic kidney disease on incident stroke seems to be higher in persons of Asian ethnicity. Since the kidney and brain share unique susceptibilities to vascular injury due to similar anatomical and functional features of small artery diseases, kidney impairment can be predictive of the presence and severity of cerebral small vessel diseases. Chronic kidney disease has been reported to be associated with silent brain infarcts, cerebral white matter lesions, and cerebral microbleeds, independently of vascular risk factors. In addition, chronic kidney disease affects cognitive function, partly via the high prevalence of cerebral small vessel diseases. Retinal artery disease also has an independent relationship with chronic kidney disease and cognitive impairment. Stroke experts are no longer allowed to be ignorant of chronic kidney disease. Close liaison between neurologists and nephrologists can improve the management of cerebral small vessel diseases in kidney patients. PMID:25692105

  9. Aging White Matter and Cognition: Differential Effects of Regional Variations in Diffusion Properties on Memory, Executive Functions, and Speed

    ERIC Educational Resources Information Center

    Kennedy, Kristen M.; Raz, Naftali

    2009-01-01

    Disruption of cerebral white matter has been proposed as an explanation for age-related cognitive declines. However, the role of specific regions in specific cognitive declines remains unclear. We used diffusion tensor imaging to examine the associations between regional microstructural integrity of the white matter and performance on…

  10. Cerebral Folate Deficiency

    ERIC Educational Resources Information Center

    Gordon, Neil

    2009-01-01

    Cerebral folate deficiency (CFD) is associated with low levels of 5-methyltetrahydrofolate in the cerebrospinal fluid (CSF) with normal folate levels in the plasma and red blood cells. The onset of symptoms caused by the deficiency of folates in the brain is at around 4 to 6 months of age. This is followed by delayed development, with deceleration…

  11. United Cerebral Palsy

    MedlinePlus

    ... be sure to follow us on Twitter ! Affiliate Network UCP affiliates provide services and support on a community-by-community basis, serving the unique needs of people with disabilities in their region. Find your ... and their networks. Individuals with cerebral palsy and other disabilities deserve ...

  12. Cerebral Palsy (For Teens)

    MedlinePlus

    ... brain is affected and which parts of the body that section of the brain controls. If CP affects both arms and both legs, ... the case of spastic CP) or to help control seizures. And some might have special surgeries to keep their arms or legs straighter and more ... Coping With Cerebral Palsy Puberty can ...

  13. Cerebral Palsy Litigation

    PubMed Central

    Sartwelle, Thomas P.

    2015-01-01

    The cardinal driver of cerebral palsy litigation is electronic fetal monitoring, which has continued unabated for 40 years. Electronic fetal monitoring, however, is based on 19th-century childbirth myths, a virtually nonexistent scientific foundation, and has a false positive rate exceeding 99%. It has not affected the incidence of cerebral palsy. Electronic fetal monitoring has, however, increased the cesarian section rate, with the expected increase in mortality and morbidity risks to mothers and babies alike. This article explains why electronic fetal monitoring remains endorsed as efficacious in the worlds’ labor rooms and courtrooms despite being such a feeble medical modality. It also reviews the reasons professional organizations have failed to condemn the use of electronic fetal monitoring in courtrooms. The failures of tort reform, special cerebral palsy courts, and damage limits to stem the escalating litigation are discussed. Finally, the authors propose using a currently available evidence rule—the Daubert doctrine that excludes “junk science” from the courtroom—as the beginning of the end to cerebral palsy litigation and electronic fetal monitoring’s 40-year masquerade as science. PMID:25183322

  14. Progress on plasma accelerators

    SciTech Connect

    Chen, P.

    1986-05-01

    Several plasma accelerator concepts are reviewed, with emphasis on the Plasma Beat Wave Accelerator (PBWA) and the Plasma Wake Field Accelerator (PWFA). Various accelerator physics issues regarding these schemes are discussed, and numerical examples on laboratory scale experiments are given. The efficiency of plasma accelerators is then revealed with suggestions on improvements. Sources that cause emittance growth are discussed briefly.

  15. Confronting White Privilege

    ERIC Educational Resources Information Center

    Swalwell, Katy

    2012-01-01

    Even as the United States becomes more diverse, a new era of "white flight" is unfolding. Whether they live in urban, suburban or rural communities, white students are likely to attend schools that reinforce their perceptions of cultural dominance. The average white student attends a school where 77 percent of the student body is of their race.…

  16. Mapping of the cerebral response to acetazolamide using graded asymmetric spin echo EPI.

    PubMed

    Mukherjee, Bhashkar; Preece, Mark; Houston, Gavin C; Papadakis, Nikolas G; Carpenter, T Adrian; Hall, Laurance D; Huang, Christopher L-H

    2005-11-01

    Cerebral vascular reactivity in different regions of the rat brain was quantitatively characterized by spatial and temporal measurements of blood oxygenation level-dependent (BOLD)-fMRI signals following intravenous administration of the carbonic anhydrase inhibitor acetazolamide: this causes cerebral vasodilatation through a cerebral extracellular acidosis that spares neuronal metabolism and vascular smooth muscle function, thus separating vascular and cerebral metabolic events. An asymmetric spin echo-echo planar imaging (ASE-EPI) pulse sequence sensitised images selectively to oxygenation changes in the microvasculature; use of a surface coil receiver enhanced image signal-to-noise ratios (SNRs). Image SNRs and hardware integrity were verified by incorporating quality assurance procedures; cardiorespiratory stability in the physiological preparations were monitored and maintained through the duration of the experiments. These conditions made it possible to apply BOLD contrast fMRI to map regional changes in cerebral perfusion in response to acetazolamide administration. Thus, fMRI findings demonstrated cerebral responses to acetazolamide that directly paralleled the known physiological actions of acetazolamide and whose time courses were similar through all regions of interest, consistent with acetazolamide's initial distribution in brain plasma, where it affects cerebral haemodynamics by acting at cerebral capillary endothelial cells. However, marked variations in the magnitude of the responses suggested relative perfusion deficits in the hippocampus and white matter regions correlating well with their relatively low vascularity and the known vulnerability of the hippocampus to ischaemic damage.

  17. Radiosurgery for cerebral arteriovenous malformations in hereditary hemorrhagic telangiectasia.

    PubMed

    Maarouf, M; Runge, M; Kocher, M; Zähringer, M; Treuer, H; Sturm, V

    2004-07-27

    The authors evaluated the efficacy of radiosurgery (RS) for cerebral arteriovenous malformations in hereditary hemorrhagic telangiectasia (HHT AVMs). Two patients with seven HHT AVMs were treated by linear accelerator-RS. Complete obliteration was achieved 18 to 24 months post-treatment without side effects. Because HHT AVMs are small and multiple, RS is superior to microsurgery because it is noninvasive and all AVMs can be treated in one session regardless of their location.

  18. Multiple Factors Involved in the Pathogenesis of White Matter Lesions

    PubMed Central

    Lin, Jing; Wang, Dilong; Lan, Linfang

    2017-01-01

    White matter lesions (WMLs), also known as leukoaraiosis (LA) or white matter hyperintensities (WMHs), are characterized mainly by hyperintensities on T2-weighted or fluid-attenuated inversion recovery (FLAIR) images. With the aging of the population and the development of imaging technology, the morbidity and diagnostic rates of WMLs are increasing annually. WMLs are not a benign process. They clinically manifest as cognitive decline and the subsequent development of dementia. Although WMLs are important, their pathogenesis is still unclear. This review elaborates on the advances in the understanding of the pathogenesis of WMLs, focusing on anatomy, cerebral blood flow autoregulation, venous collagenosis, blood brain barrier disruption, and genetic factors. In particular, the attribution of WMLs to chronic ischemia secondary to venous collagenosis and cerebral blood flow autoregulation disruption seems reasonable. With the development of gene technology, the effect of genetic factors on the pathogenesis of WMLs is gaining gradual attention. PMID:28316994

  19. Age exacerbates HIV-associated white matter abnormalities.

    PubMed

    Seider, Talia R; Gongvatana, Assawin; Woods, Adam J; Chen, Huaihou; Porges, Eric C; Cummings, Tiffany; Correia, Stephen; Tashima, Karen; Cohen, Ronald A

    2016-04-01

    Both HIV disease and advanced age have been associated with alterations to cerebral white matter, as measured with white matter hyperintensities (WMH) on fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI), and more recently with diffusion tensor imaging (DTI). This study investigates the combined effects of age and HIV serostatus on WMH and DTI measures, as well as the relationships between these white matter measures, in 88 HIV seropositive (HIV+) and 49 seronegative (HIV-) individuals aged 23-79 years. A whole-brain volumetric measure of WMH was quantified from FLAIR images using a semi-automated process, while fractional anisotropy (FA) was calculated for 15 regions of a whole-brain white matter skeleton generated using tract-based spatial statistics (TBSS). An age by HIV interaction was found indicating a significant association between WMH and older age in HIV+ participants only. Similarly, significant age by HIV interactions were found indicating stronger associations between older age and decreased FA in the posterior limbs of the internal capsules, cerebral peduncles, and anterior corona radiata in HIV+ vs. HIV- participants. The interactive effects of HIV and age were stronger with respect to whole-brain WMH than for any of the FA measures. Among HIV+ participants, greater WMH and lower anterior corona radiata FA were associated with active hepatitis C virus infection, a history of AIDS, and higher current CD4 cell count. Results indicate that age exacerbates HIV-associated abnormalities of whole-brain WMH and fronto-subcortical white matter integrity.

  20. Managing Malignant Cerebral Infarction

    PubMed Central

    Sahuquillo, Juan; Sheth, Kevin N.; Kahle, Kristopher T.; Walcott, Brian P.

    2011-01-01

    Opinion statement Managing patients with malignant cerebral infarction remains one of the foremost challenges in medicine. These patients are at high risk for progressive neurologic deterioration and death due to malignant cerebral edema, and they are best cared for in the intensive care unit of a comprehensive stroke center. Careful initial assessment of neurologic function and of findings on MRI, coupled with frequent reassessment of clinical and radiologic findings using CT or MRI are mandatory to promote the prompt initiation of treatments that will ensure the best outcome in these patients. Significant deterioration in either neurologic function or radiologic findings or both demand timely treatment using the best medical management, which may include osmotherapy (mannitol or hypertonic saline), endotracheal intubation, and mechanical ventilation. Under appropriate circumstances, decompressive craniectomy may be warranted to improve outcome or to prevent death. PMID:21190097

  1. High Altitude Cerebral Edema

    DTIC Science & Technology

    1986-03-01

    English literature and Hultgren et al (3.1) described four more cases of HAPE within the next year. In 1960, Chiodi (5) first reported on a Peruvian...altitude and treatment with steroids and diuretics, CSF pressure was 85 mm H 0. In 1960, Chiodi .(5) described a patient 2 suffering with HACE who...Biol. Chem., 157, 297-302, 1945. 5. Chiodi H: "Mal de montana a forma cerebral; possible mecanismo etiopathogenico," An. Fac. Med. Lima., 43, 437

  2. Primary cerebral malignant melanoma

    PubMed Central

    Tang, Kai; Kong, Xiangyi; Mao, Gengsheng; Qiu, Ming; Zhu, Haibo; Zhou, Lei; Nie, Qingbin; Xu, Yi; Du, Shiwei

    2017-01-01

    Abstract Primary intracranial melanomas are uncommon and constitute approximately 1% of all melanoma cases and 0.07% of all brain tumors. In nature, these primary melanomas are very aggressive and can spread to other organs. We report an uncommon case of primary cerebral malignant melanoma—a challenging diagnosis guided by clinical presentations, radiological features, and surgical biopsy results, aiming to emphasize the importance of considering primary melanoma when making differential diagnoses of intracranial lesions. We present a rare case of a primary cerebral melanoma in the left temporal lobe. The mass appeared iso-hypodense on brain computed tomography (CT), short signal on T1-weighted magnetic resonance images (T1WI) and long signal on T2WI. It was not easy to make an accurate diagnosis before surgery. We showed the patient's disease course and reviewed related literatures, for readers’ reference. Written informed consent was obtained from the patient for publication of this case report and any accompanying images. Because of this, there is no need to conduct special ethic review and the ethical approval is not necessary. After surgery, the pathological examination confirmed the diagnosis of melanoma. The patient was discharged without any complications and went on to receive adjuvant radiochemotherapy. It is difficult to diagnose primary cerebral melanoma in the absence of any cutaneous melanosis. A high index of clinical suspicion along with good pathology reporting is the key in diagnosing these extremely rare tumors. PMID:28121927

  3. Nonhuman primate models of focal cerebral ischemia

    PubMed Central

    Fan, Jingjing; Li, Yi; Fu, Xinyu; Li, Lijuan; Hao, Xiaoting; Li, Shasha

    2017-01-01

    Rodents have been widely used in the production of cerebral ischemia models. However, successful therapies have been proven on experimental rodent stroke model, and they have often failed to be effective when tested clinically. Therefore, nonhuman primates were recommended as the ideal alternatives, owing to their similarities with the human cerebrovascular system, brain metabolism, grey to white matter ratio and even their rich behavioral repertoire. The present review is a thorough summary of ten methods that establish nonhuman primate models of focal cerebral ischemia; electrocoagulation, endothelin-1-induced occlusion, microvascular clip occlusion, autologous blood clot embolization, balloon inflation, microcatheter embolization, coil embolization, surgical suture embolization, suture, and photochemical induction methods. This review addresses the advantages and disadvantages of each method, as well as precautions for each model, compared nonhuman primates with rodents, different species of nonhuman primates and different modeling methods. Finally it discusses various factors that need to be considered when modelling and the method of evaluation after modelling. These are critical for understanding their respective strengths and weaknesses and underlie the selection of the optimum model.

  4. Molecular pathophysiology of cerebral edema

    PubMed Central

    Gerzanich, Volodymyr; Simard, J Marc

    2015-01-01

    Advancements in molecular biology have led to a greater understanding of the individual proteins responsible for generating cerebral edema. In large part, the study of cerebral edema is the study of maladaptive ion transport. Following acute CNS injury, cells of the neurovascular unit, particularly brain endothelial cells and astrocytes, undergo a program of pre- and post-transcriptional changes in the activity of ion channels and transporters. These changes can result in maladaptive ion transport and the generation of abnormal osmotic forces that, ultimately, manifest as cerebral edema. This review discusses past models and current knowledge regarding the molecular and cellular pathophysiology of cerebral edema. PMID:26661240

  5. Molecular pathophysiology of cerebral edema.

    PubMed

    Stokum, Jesse A; Gerzanich, Volodymyr; Simard, J Marc

    2016-03-01

    Advancements in molecular biology have led to a greater understanding of the individual proteins responsible for generating cerebral edema. In large part, the study of cerebral edema is the study of maladaptive ion transport. Following acute CNS injury, cells of the neurovascular unit, particularly brain endothelial cells and astrocytes, undergo a program of pre- and post-transcriptional changes in the activity of ion channels and transporters. These changes can result in maladaptive ion transport and the generation of abnormal osmotic forces that, ultimately, manifest as cerebral edema. This review discusses past models and current knowledge regarding the molecular and cellular pathophysiology of cerebral edema.

  6. Future accelerator technology

    SciTech Connect

    Sessler, A.M.

    1986-05-01

    A general discussion is presented of the acceleration of particles. Upon this foundation is built a categorization scheme into which all accelerators can be placed. Special attention is devoted to accelerators which employ a wake-field mechanism and a restricting theorem is examined. It is shown how the theorem may be circumvented. Comments are made on various acceleration schemes.

  7. ACCELERATION AND THE GIFTED.

    ERIC Educational Resources Information Center

    GIBSON, ARTHUR R.; STEPHANS, THOMAS M.

    ACCELERATION OF PUPILS AND SUBJECTS IS CONSIDERED A MEANS OF EDUCATING THE ACADEMICALLY GIFTED STUDENT. FIVE INTRODUCTORY ARTICLES PROVIDE A FRAMEWORK FOR THINKING ABOUT ACCELERATION. FIVE PROJECT REPORTS OF ACCELERATED PROGRAMS IN OHIO ARE INCLUDED. ACCELERATION IS NOW BEING REGARDED MORE FAVORABLY THAN FORMERLY, BECAUSE METHODS HAVE BEEN…

  8. Laser driven ion accelerator

    DOEpatents

    Tajima, Toshiki

    2005-06-14

    A system and method of accelerating ions in an accelerator to optimize the energy produced by a light source. Several parameters may be controlled in constructing a target used in the accelerator system to adjust performance of the accelerator system. These parameters include the material, thickness, geometry and surface of the target.

  9. Laser driven ion accelerator

    DOEpatents

    Tajima, Toshiki

    2006-04-18

    A system and method of accelerating ions in an accelerator to optimize the energy produced by a light source. Several parameters may be controlled in constructing a target used in the accelerator system to adjust performance of the accelerator system. These parameters include the material, thickness, geometry and surface of the target.

  10. White Matter Disruptions in Schizophrenia Are Spatially Widespread and Topologically Converge on Brain Network Hubs.

    PubMed

    Klauser, Paul; Baker, Simon T; Cropley, Vanessa L; Bousman, Chad; Fornito, Alex; Cocchi, Luca; Fullerton, Janice M; Rasser, Paul; Schall, Ulrich; Henskens, Frans; Michie, Patricia T; Loughland, Carmel; Catts, Stanley V; Mowry, Bryan; Weickert, Thomas W; Shannon Weickert, Cynthia; Carr, Vaughan; Lenroot, Rhoshel; Pantelis, Christos; Zalesky, Andrew

    2016-08-17

    White matter abnormalities associated with schizophrenia have been widely reported, although the consistency of findings across studies is moderate. In this study, neuroimaging was used to investigate white matter pathology and its impact on whole-brain white matter connectivity in one of the largest samples of patients with schizophrenia. Fractional anisotropy (FA) and mean diffusivity (MD) were compared between patients with schizophrenia or schizoaffective disorder (n = 326) and age-matched healthy controls (n = 197). Between-group differences in FA and MD were assessed using voxel-based analysis and permutation testing. Automated whole-brain white matter fiber tracking and the network-based statistic were used to characterize the impact of white matter pathology on the connectome and its rich club. Significant reductions in FA associated with schizophrenia were widespread, encompassing more than 40% (234ml) of cerebral white matter by volume and involving all cerebral lobes. Significant increases in MD were also widespread and distributed similarly. The corpus callosum, cingulum, and thalamic radiations exhibited the most extensive pathology according to effect size. More than 50% of cortico-cortical and cortico-subcortical white matter fiber bundles comprising the connectome were disrupted in schizophrenia. Connections between hub regions comprising the rich club were disproportionately affected. Pathology did not differ between patients with schizophrenia and schizoaffective disorder and was not mediated by medication. In conclusion, although connectivity between cerebral hubs is most extensively disturbed in schizophrenia, white matter pathology is widespread, affecting all cerebral lobes and the cerebellum, leading to disruptions in the majority of the brain's fiber bundles.

  11. Pulsed arterial spin labeling effectively and dynamically observes changes in cerebral blood flow after mild traumatic brain injury.

    PubMed

    Peng, Shu-Ping; Li, Yi-Ning; Liu, Jun; Wang, Zhi-Yuan; Zhang, Zi-Shu; Zhou, Shun-Ke; Tao, Fang-Xu; Zhang, Zhi-Xue

    2016-02-01

    Cerebral blood flow is strongly associated with brain function, and is the main symptom and diagnostic basis for a variety of encephalopathies. However, changes in cerebral blood flow after mild traumatic brain injury remain poorly understood. This study sought to observe changes in cerebral blood flow in different regions after mild traumatic brain injury using pulsed arterial spin labeling. Our results demonstrate maximal cerebral blood flow in gray matter and minimal in the white matter of patients with mild traumatic brain injury. At the acute and subacute stages, cerebral blood flow was reduced in the occipital lobe, parietal lobe, central region, subcutaneous region, and frontal lobe. Cerebral blood flow was restored at the chronic stage. At the acute, subacute, and chronic stages, changes in cerebral blood flow were not apparent in the insula. Cerebral blood flow in the temporal lobe and limbic lobe diminished at the acute and subacute stages, but was restored at the chronic stage. These findings suggest that pulsed arterial spin labeling can precisely measure cerebral blood flow in various brain regions, and may play a reference role in evaluating a patient's condition and judging prognosis after traumatic brain injury.

  12. Whiteness in Social Work Education Authentic White Allies

    ERIC Educational Resources Information Center

    Hornung, Rebecca

    2012-01-01

    This dissertation is guided by the following questions: How do People of Color define and experience White people as "authentic" allies? What does a White ally look like to People of Color? How do White allies view themselves as "authentic" White allies? What experiences lead White people to anti-racism and anti-racist praxis?…

  13. Middle Cerebral Artery Calcification

    PubMed Central

    Kao, Hung-Wen; Liou, Michelle; Chung, Hsiao-Wen; Liu, Hua-Shan; Tsai, Ping-Huei; Chiang, Shih-Wei; Chou, Ming-Chung; Peng, Giia-Sheun; Huang, Guo-Shu; Hsu, Hsian-He; Chen, Cheng-Yu

    2015-01-01

    Abstract Calcification of the middle cerebral artery (MCA) is uncommon in the healthy elderly. Whether calcification of the MCA is associated with cerebral ischemic stroke remains undetermined. We intended to investigate the association using Agatston calcium scoring of the MCA. This study retrospectively included 354 subjects with ischemic stroke in the MCA territory and 1518 control subjects who underwent computed tomography (CT) of the brain. We recorded major known risk factors for ischemic stroke, including age, gender, hypertension, diabetes mellitus, smoking, hyperlipidemia, and obesity, along with the MCA calcium burden, measured with the Agatston calcium scoring method. Univariate and modified logistic regression analyses were performed to examine the association between the MCA calcification and ischemic stroke. The univariate analyses showed significant associations of ischemic stroke with age, hypertension, diabetes mellitus, smoking, total MCA Agatston score, and the presence of calcification on both or either side of the MCA. Subjects with the presence of MCA calcification on both or either side of the MCA were 8.46 times (95% confidence interval, 4.93–14.53; P < 0.001) more likely to have a cerebral infarct than subjects without MCA calcification after adjustment for the major known risk factors, including age, hypertension, diabetes mellitus, and smoking. However, a higher degree of MCA calcification reflected by the Agatston score was not associated with higher risk of MCA ischemic stroke after adjustment for the confounding factors and presence of MCA calcification. These results suggest that MCA calcification is associated with ischemic stroke in the MCA territory. Further prospective studies are required to verify the clinical implications of the MCA calcification. PMID:26683969

  14. Resting cerebral blood flow

    PubMed Central

    Ances, B M.; Sisti, D; Vaida, F; Liang, C L.; Leontiev, O; Perthen, J E.; Buxton, R B.; Benson, D; Smith, D M.; Little, S J.; Richman, D D.; Moore, D J.; Ellis, R J.

    2009-01-01

    Objective: HIV enters the brain soon after infection causing neuronal damage and microglial/astrocyte dysfunction leading to neuropsychological impairment. We examined the impact of HIV on resting cerebral blood flow (rCBF) within the lenticular nuclei (LN) and visual cortex (VC). Methods: This cross-sectional study used arterial spin labeling MRI (ASL-MRI) to measure rCBF within 33 HIV+ and 26 HIV− subjects. Nonparametric Wilcoxon rank sum test assessed rCBF differences due to HIV serostatus. Classification and regression tree (CART) analysis determined optimal rCBF cutoffs for differentiating HIV serostatus. The effects of neuropsychological impairment and infection duration on rCBF were evaluated. Results: rCBF within the LN and VC were significantly reduced for HIV+ compared to HIV− subjects. A 2-tiered CART approach using either LN rCBF ≤50.09 mL/100 mL/min or LN rCBF >50.09 mL/100 mL/min but VC rCBF ≤37.05 mL/100 mL/min yielded an 88% (29/33) sensitivity and an 88% (23/26) specificity for differentiating by HIV serostatus. HIV+ subjects, including neuropsychologically unimpaired, had reduced rCBF within the LN (p = 0.02) and VC (p = 0.001) compared to HIV− controls. A temporal progression of brain involvement occurred with LN rCBF significantly reduced for both acute/early (<1 year of seroconversion) and chronic HIV-infected subjects, whereas rCBF in the VC was diminished for only chronic HIV-infected subjects. Conclusion: Resting cerebral blood flow (rCBF) using arterial spin labeling MRI has the potential to be a noninvasive neuroimaging biomarker for assessing HIV in the brain. rCBF reductions that occur soon after seroconversion possibly reflect neuronal or vascular injury among HIV+ individuals not yet expressing neuropsychological impairment. GLOSSARY AEH = acute/early HIV infection; ANOVA = analysis of variance; ASL-MRI = arterial spin labeling MRI; CART = classification and regression tree; CBF = cerebral blood flow; CH = chronic HIV

  15. Cerebral Disorders of Calves.

    PubMed

    Dore, Vincent; Smith, Geof

    2017-03-01

    Neurologic diseases of the cerebrum are relatively common in cattle. In calves, the primary cerebral disorders are polioencephalomalacia, meningitis, and sodium toxicity. Because diagnostic testing is not always readily available, the practitioner must often decide on a course of treatment based on knowledge of the likely disease, as well as his or her own clinical experience. This is particularly true with neurologic diseases in which the prognosis is often poor and euthanasia may be the most humane outcome. This article reviews the most common diseases affecting the cerebrum of calves with a focus on pathophysiology, diagnosis, and treatment.

  16. Subcortical ischemic vascular disease: Roles of oligodendrocyte function in experimental models of subcortical white-matter injury.

    PubMed

    Shindo, Akihiro; Liang, Anna C; Maki, Takakuni; Miyamoto, Nobukazu; Tomimoto, Hidekazu; Lo, Eng H; Arai, Ken

    2016-01-01

    Oligodendrocytes are one of the major cell types in cerebral white matter. Under normal conditions, they form myelin sheaths that encircle axons to support fast nerve conduction. Under conditions of cerebral ischemia, oligodendrocytes tend to die, resulting in white-matter dysfunction. Repair of white matter involves the ability of oligodendrocyte precursors to proliferate and mature. However, replacement of lost oligodendrocytes may not be the only mechanism for white-matter recovery. Emerging data now suggest that coordinated signaling between neural, glial, and vascular cells in the entire neurovascular unit may be required. In this mini-review, we discuss how oligodendrocyte lineage cells participate in signaling and crosstalk with other cell types to underlie function and recovery in various experimental models of subcortical white-matter injury.

  17. Subcortical ischemic vascular disease: Roles of oligodendrocyte function in experimental models of subcortical white-matter injury

    PubMed Central

    Shindo, Akihiro; Liang, Anna C; Maki, Takakuni; Miyamoto, Nobukazu; Tomimoto, Hidekazu; Lo, Eng H

    2016-01-01

    Oligodendrocytes are one of the major cell types in cerebral white matter. Under normal conditions, they form myelin sheaths that encircle axons to support fast nerve conduction. Under conditions of cerebral ischemia, oligodendrocytes tend to die, resulting in white-matter dysfunction. Repair of white matter involves the ability of oligodendrocyte precursors to proliferate and mature. However, replacement of lost oligodendrocytes may not be the only mechanism for white-matter recovery. Emerging data now suggest that coordinated signaling between neural, glial, and vascular cells in the entire neurovascular unit may be required. In this mini-review, we discuss how oligodendrocyte lineage cells participate in signaling and crosstalk with other cell types to underlie function and recovery in various experimental models of subcortical white-matter injury. PMID:25920960

  18. Cerebral potentials and leg muscle e.m.g. responses associated with stance perturbation.

    PubMed

    Dietz, V; Quintern, J; Berger, W; Schenck, E

    1985-01-01

    In order to investigate the neuronal mechanisms underlying the compensatory movements following stance disturbance, leg muscle e.m.g. responses and cerebral potentials evoked by a treadmill acceleration impulse were analysed. It was found that the displacement was followed by a cerebral potential of a latency of 40-45 ms and EMG responses in the calf muscles at a latency of 65-70 ms. The e.m.g. responses represented specific compensatory reactions to the mode of perturbation (with a gastrocnemius activation following positive acceleration but a tibialis ant. activation following negative acceleration). The cerebral potentials, however, showed a common pattern to both conditions. In addition, the leg muscle e.m.g. reactions were not altered by learning effects and by forewarning of displacement onset, while the amplitude of the cerebral potentials was significantly smaller in these conditions compared to those produced in response to randomly induced perturbations. It was therefore concluded that the leg muscle e.m.g. reactions are mediated by a polysynaptic spinal reflex pathway which depends on a supraspinal control. The cerebral potentials seem to represent afferent signals which can be supposed to be subjected to modification and processing by supraspinal motor centres, according to the actual requirements.

  19. Cerebral phaeohyphomycosis caused by a dematiaceous scopulariopsis species.

    PubMed

    Hart, A P; Sutton, D A; McFeeley, P J; Kornfeld, M

    2001-01-01

    This report describes a rapidly fatal case of cerebral phaeohyphomycosis in a 33-year-old immunocompetent male. The infection presented as a single large lesion in the deep white matter of one temporal lobe, which was then removed surgically. Histologic features observed in the lobectomy specimen were characterized by perivascular sleeves of mononuclear cells accompanied by hemorrhages. These were reminiscent of acute hemorrhagic leukoencephalitis except for the presence of rare fungal organisms and sparse multinucleated giant cells similar to those occurring in AIDS. During the four days following surgery, a large focus of cerebritis with massive invasion of fungi developed in each centrum semiovale around the ventriculostomy sites. Fungal culture of the brain obtained at autopsy grew an organism consistent with a Scopulariopsis species.

  20. Selective vulnerability of preterm white matter to oxidative damage defined by F2-isoprostanes.

    PubMed

    Back, Stephen A; Luo, Ning Ling; Mallinson, Rebecca A; O'Malley, Jean P; Wallen, Linda D; Frei, Balz; Morrow, Jason D; Petito, Carol K; Roberts, Charles T; Murdoch, Geoffrey H; Montine, Thomas J

    2005-07-01

    Periventricular white matter injury (PWMI) is the leading cause of cerebral palsy and chronic neurological disability in survivors of prematurity. Despite the large number of affected children, the pathogenetic mechanisms related to PWMI remain controversial. Through studies of 33 human autopsy brains, we determined that early PWMI was related to oxidative damage that particularly targeted the oligodendrocyte lineage, whereas other neuronal and glial cell types were markedly more resistant. F(2)-isoprostanes, an arachidinate metabolite/lipid peroxidation marker of oxidative damage, were significantly increased in early PWMI lesions but not in cerebral cortex. That deleterious lipid peroxidation accompanied early PWMI was supported by similar increases in F(2)-isoprostanes levels in the cerebral cortex from term infants with hypoxic-ischemic cortical injury. Detection of F(4)-neuroprostanes, a neuronal-specific oxidative damage marker, confirmed that neuroaxonal elements were resistant to injury in cerebral cortex and white matter. Significant protein nitration was not detected in PWMI lesions by 3-nitrotyrosine staining. Significant cellular degeneration was confirmed in early PWMI lesions by terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling and a marked depletion of oligodendrocyte progenitors of 71 +/- 8%. Hence, the predilection of preterm infants for PWMI is related to selective lipid peroxidation-mediated injury of cerebral white matter and targeted death of oligodendrocyte progenitors.

  1. Changes in cerebral blood flow, cerebral metabolites, and breathing movements in the sheep fetus following asphyxia produced by occlusion of the umbilical cord.

    PubMed

    Yan, Edwin B; Baburamani, Ana A; Walker, Adrian M; Walker, David W

    2009-07-01

    Severe global fetal asphyxia, if caused by a brief occlusion of the umbilical cord, results in prolonged cerebral hypoperfusion in fetal sheep. In this study, we sought evidence to support the hypothesis that cerebral hypoperfusion is a consequence of suppressed cerebral metabolism. In the 24 h following complete occlusion of the umbilical cord for 10 min, sagittal sinus blood flow velocity was significantly decreased for up to 12 h. Capillary blood flow, measured using microspheres, decreased at 1 and 5 h after cord occlusion in many brain regions, including cortical gray and white matter. Microdialysis probes implanted in the cerebral cortex revealed an increase in extracellular glucose concentrations in gray matter for 7-8 h postasphyxia, while lactate increased only briefly, suggesting decreased cerebral glucose utilization over this time. Although these data, as well as the concurrent suppression of breathing movements and electrocortical activity, support the concept of hypometabolic hypoperfusion, the significant increase of pyruvate and glycerol concentrations in dialysate fluid obtained from the cerebral cortex at 3-8 h after cord occlusion suggests an eventual loss of membrane integrity. The prolonged increase of breathing movements for many hours suggests loss of the pontine/thalamic control that produces the distinct pattern of fetal breathing movements.

  2. White Flight: Some Hypotheses.

    ERIC Educational Resources Information Center

    Wegmann, Robert G.

    The available literature on white flight, or, more properly, school resegregation -- the phenomenon of white withdrawal (total or partial) from desegregated schools -- is reviewed in this paper which also reports some new research in this area. The distinction is made between those schools located on the fringes of the inner city, which first…

  3. White Teachers Talking Race

    ERIC Educational Resources Information Center

    Segall, Avner; Garrett, James

    2013-01-01

    In light of the increasing racial diversity in American schools and the consistently homogenous teacher workforce in the United States, understanding the ways white teachers consider and attend to racial issues is of crucial importance to the educational landscape. This paper, based on a qualitative study, explores five white American teachers'…

  4. The Hidden Curriculum of Whiteness: White Teachers, White Territory, and White Community.

    ERIC Educational Resources Information Center

    Allen, Ricky Lee

    This paper suggests that space and spatiality are major features of racial identity and the formation of student resistance. It brings together critical studies of "Whiteness," human territoriality, and theories of resistance in education. The problems between white teachers and students of color can be understood better through a combination of…

  5. Sailing to White Boat

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This is a composite red-green-blue image of the rock called White Boat. It is the first rock target that Spirit drove to after finishing a series of investigations on the rock Adirondack. White Boat stood out to scientists due to its light color and more tabular shape compared to the dark, rounded rocks that surround it.

  6. Whites in Desegregated Schools.

    ERIC Educational Resources Information Center

    Northwestern Univ., Evanston, IL. Center for Equal Education.

    In 1972, over 1.3 million white children attended schools in which they were a minority. This document consists of articles addressing this little studied phenomenon. In Gretchen Schafft's article, an anthropological method is employed to study the role of white children in a predominantly black junior high school in Washington, D.C. Jean Le…

  7. Cerebral Gluconeogenesis and Diseases

    PubMed Central

    Yip, James; Geng, Xiaokun; Shen, Jiamei; Ding, Yuchuan

    2017-01-01

    The gluconeogenesis pathway, which has been known to normally present in the liver, kidney, intestine, or muscle, has four irreversible steps catalyzed by the enzymes: pyruvate carboxylase, phosphoenolpyruvate carboxykinase, fructose 1,6-bisphosphatase, and glucose 6-phosphatase. Studies have also demonstrated evidence that gluconeogenesis exists in brain astrocytes but no convincing data have yet been found in neurons. Astrocytes exhibit significant 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3 activity, a key mechanism for regulating glycolysis and gluconeogenesis. Astrocytes are unique in that they use glycolysis to produce lactate, which is then shuttled into neurons and used as gluconeogenic precursors for reduction. This gluconeogenesis pathway found in astrocytes is becoming more recognized as an important alternative glucose source for neurons, specifically in ischemic stroke and brain tumor. Further studies are needed to discover how the gluconeogenesis pathway is controlled in the brain, which may lead to the development of therapeutic targets to control energy levels and cellular survival in ischemic stroke patients, or inhibit gluconeogenesis in brain tumors to promote malignant cell death and tumor regression. While there are extensive studies on the mechanisms of cerebral glycolysis in ischemic stroke and brain tumors, studies on cerebral gluconeogenesis are limited. Here, we review studies done to date regarding gluconeogenesis to evaluate whether this metabolic pathway is beneficial or detrimental to the brain under these pathological conditions. PMID:28101056

  8. Cerebral cartography and connectomics

    PubMed Central

    Sporns, Olaf

    2015-01-01

    Cerebral cartography and connectomics pursue similar goals in attempting to create maps that can inform our understanding of the structural and functional organization of the cortex. Connectome maps explicitly aim at representing the brain as a complex network, a collection of nodes and their interconnecting edges. This article reflects on some of the challenges that currently arise in the intersection of cerebral cartography and connectomics. Principal challenges concern the temporal dynamics of functional brain connectivity, the definition of areal parcellations and their hierarchical organization into large-scale networks, the extension of whole-brain connectivity to cellular-scale networks, and the mapping of structure/function relations in empirical recordings and computational models. Successfully addressing these challenges will require extensions of methods and tools from network science to the mapping and analysis of human brain connectivity data. The emerging view that the brain is more than a collection of areas, but is fundamentally operating as a complex networked system, will continue to drive the creation of ever more detailed and multi-modal network maps as tools for on-going exploration and discovery in human connectomics. PMID:25823870

  9. Cerebral hyperperfusion syndrome.

    PubMed

    van Mook, Walther N K A; Rennenberg, Roger J M W; Schurink, Geert Willem; van Oostenbrugge, Robert Jan; Mess, Werner H; Hofman, Paul A M; de Leeuw, Peter W

    2005-12-01

    Cerebral hyperperfusion syndrome (CHS) after carotid endarterectomy is characterised by ipsilateral headache, hypertension, seizures, and focal neurological deficits. If not treated properly it can result in severe brain oedema, intracerebral or subarachnoid haemorrhage, and death. Knowledge of CHS among physicians is limited. Most studies report incidences of CHS of 0-3% after carotid endarterectomy. CHS is most common in patients with increases of more than 100% in perfusion compared with baseline after carotid endarterectomy and is rare in patients with increases in perfusion less than 100% compared with baseline. The most important risk factors in CHS are diminished cerebrovascular reserve, postoperative hypertension, and hyperperfusion lasting more than several hours after carotid endarterectomy. Impaired autoregulation as a result of endothelial dysfunction mediated by generation of free oxygen radicals is implicated in the pathogenesis of CHS. Treatment strategies are directed towards regulation of blood pressure and limitation of rises in cerebral perfusion. Complete recovery happens in mild cases, but disability and death can occur in more severe cases. More information about CHS and early institution of adequate treatment are of paramount importance in order to prevent these potentially severe complications.

  10. Cerebral cartography and connectomics.

    PubMed

    Sporns, Olaf

    2015-05-19

    Cerebral cartography and connectomics pursue similar goals in attempting to create maps that can inform our understanding of the structural and functional organization of the cortex. Connectome maps explicitly aim at representing the brain as a complex network, a collection of nodes and their interconnecting edges. This article reflects on some of the challenges that currently arise in the intersection of cerebral cartography and connectomics. Principal challenges concern the temporal dynamics of functional brain connectivity, the definition of areal parcellations and their hierarchical organization into large-scale networks, the extension of whole-brain connectivity to cellular-scale networks, and the mapping of structure/function relations in empirical recordings and computational models. Successfully addressing these challenges will require extensions of methods and tools from network science to the mapping and analysis of human brain connectivity data. The emerging view that the brain is more than a collection of areas, but is fundamentally operating as a complex networked system, will continue to drive the creation of ever more detailed and multi-modal network maps as tools for on-going exploration and discovery in human connectomics.

  11. Monitoring of cerebral autoregulation.

    PubMed

    Czosnyka, Marek; Miller, Chad

    2014-12-01

    Pressure autoregulation is an important hemodynamic mechanism that protects the brain against inappropriate fluctuations in cerebral blood flow in the face of changing cerebral perfusion pressure (CPP). Static autoregulation represents how far cerebrovascular resistance changes when CPP varies, and dynamic autoregulation represents how fast these changes happen. Both have been monitored in the setting of neurocritical care to aid prognostication and contribute to individualizing CPP targets in patients. Failure of autoregulation is associated with a worse outcome in various acute neurological diseases. Several studies have used transcranial Doppler ultrasound, intracranial pressure (ICP with vascular reactivity as surrogate measure of autoregulation), and near-infrared spectroscopy to continuously monitor the impact of spontaneous fluctuations in CPP on cerebrovascular physiology and to calculate derived variables of autoregulatory efficiency. Many patients who undergo such monitoring demonstrate a range of CPP in which autoregulatory efficiency is optimal. Management of patients at or near this optimal level of CPP is associated with better outcomes in traumatic brain injury. Many of these studies have utilized the concept of the pressure reactivity index, a correlation coefficient between ICP and mean arterial pressure. While further studies are needed, these data suggest that monitoring of autoregulation could aid prognostication and may help identify optimal CPP levels in individual patients.

  12. Cerebral sinus venous thrombosis

    PubMed Central

    Alvis-Miranda, Hernando Raphael; Milena Castellar-Leones, Sandra; Alcala-Cerra, Gabriel; Rafael Moscote-Salazar, Luis

    2013-01-01

    Cerebral sinus venous thrombosis (CSVT) is a rare phenomenon that can be seen with some frequency in young patients. CSVT is a multifactorial condition with gender-related specific causes, with a wide clinical presentation, the leading causes differ between developed and developing countries, converting CSVT in a condition characterized by a highly variable clinical spectra, difficult diagnosis, variable etiologies and prognosis that requires fine medical skills and a high suspicious index. Patients who presents with CSVT should underwent to CT-scan venography (CVT) and to the proper inquiry of the generating cause. This disease can affect the cerebral venous drainage and related anatomical structure. The symptoms may appear in relation to increased intracranial pressure imitating a pseudotumorcerebri. Prognosis depends on the early detection. Correcting the cause, generally the complications can be prevented. Mortality trends have diminished, and with the new technologies, surely it will continue. This work aims to review current knowledge about CSVT including its pathogenesis, etiology, clinical manifestations, diagnosis, and treatment. PMID:24347950

  13. [Noradrenaline and cerebral aging].

    PubMed

    Jouvet, M; Albarede, J L; Lubin, S; Meyrignac, C

    1991-01-01

    The central functions of norepinephrine (NE) are a recent discovery: regulation of alertness and of the wakefulness-sleep cycle, maintenance of attention, memory and learning, cerebral plasticity and neuro-protection. The anatomical, histological, biochemical and physiological properties of the central noradrenergic system: extreme capacity for ramification and arborization; slow conduction, non-myelinized axons with extrasynaptic varicosities producing and releasing NE; frequency of co-transmission phenomena, and; neuromodulation with fiber effect responsible for improvement in the signal over background noise ratio and selection of significant stimuli form a true interface between the outside world and the central nervous system, notably for the neocortex in the context of the cognitive treatment of information. This central noradrenergic system is involved in the neurophysiology and the clinical features of cerebral aging (ideation-motor and cognitive function slowing down, loss of behavioral adjustment), neuro-degenerative disorders (SDAT, Parkinson's disease), certain aspects of depression and less obvious conditions (head injuries, sequelae of cerebrovascular accidents, sub-cortical dementia). The recent development of medications improving alertness (adrafinil, modafinil) with a pure central action and specifically noradrenergic, may contribute to an improvement in these multifactorial disorders.

  14. Working decks for buoy maintenance. White Sage on left, White ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Working decks for buoy maintenance. White Sage on left, White Holly on right. - U.S. Coast Guard Cutter WHITE HOLLY, U.S. Coast Guard 8th District Base, 4640 Urquhart Street, New Orleans, Orleans Parish, LA

  15. Elevation from east. White Holly in foreground, with White Sage ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Elevation from east. White Holly in foreground, with White Sage behind. - U.S. Coast Guard Cutter WHITE HOLLY, U.S. Coast Guard 8th District Base, 4640 Urquhart Street, New Orleans, Orleans Parish, LA

  16. Inter-Parietal White Matter Development Predicts Numerical Performance in Young Children

    ERIC Educational Resources Information Center

    Cantlon, Jessica F.; Davis, Simon W.; Libertus, Melissa E.; Kahane, Jill; Brannon, Elizabeth M.; Pelphrey, Kevin A.

    2011-01-01

    In an effort to understand the role of interhemispheric transfer in numerical development, we investigated the relationship between children's developing knowledge of numbers and the integrity of their white matter connections between the cerebral hemispheres (the corpus callosum). We used diffusion tensor imaging (DTI) tractography analyses to…

  17. Neonatal White Matter Abnormality Predicts Childhood Motor Impairment in Very Preterm Children

    ERIC Educational Resources Information Center

    Spittle, Alicia J.; Cheong, Jeanie; Doyle, Lex W.; Roberts, Gehan; Lee, Katherine J.; Lim, Jeremy; Hunt, Rod W.; Inder, Terrie E.; Anderson, Peter J.

    2011-01-01

    Aim: Children born very preterm are at risk for impaired motor performance ranging from cerebral palsy (CP) to milder abnormalities, such as developmental coordination disorder. White matter abnormalities (WMA) at term have been associated with CP in very preterm children; however, little is known about the impact of WMA on the range of motor…

  18. The Embeddedness of White Fragility within White Pre-Service Principals' Reflections on White Privilege

    ERIC Educational Resources Information Center

    Hines, Mack T., III

    2016-01-01

    This study analyzes the prevalence of white fragility within the six white, pre-service principals' online responses to readings about white privilege. Six white, pre-service principals were asked to provide commentary to class readings on the relevance of white privilege to their preparation for future positions as principals. The findings showed…

  19. Accelerating Particles with Plasma

    ScienceCinema

    Litos, Michael; Hogan, Mark

    2016-07-12

    Researchers at SLAC explain how they use plasma wakefields to accelerate bunches of electrons to very high energies over only a short distance. Their experiments offer a possible path for the future of particle accelerators.

  20. Peak acceleration limiter

    NASA Technical Reports Server (NTRS)

    Chapman, C. P.

    1972-01-01

    Device is described that limits accelerations by shutting off shaker table power very rapidly in acceleration tests. Absolute value of accelerometer signal is used to trigger electronic switch which terminates test and sounds alarm.

  1. Linear Accelerator (LINAC)

    MedlinePlus

    ... equipment? How is safety ensured? What is this equipment used for? A linear accelerator (LINAC) is the ... Therapy (SBRT) . top of page How does the equipment work? The linear accelerator uses microwave technology (similar ...

  2. Accelerating Particles with Plasma

    SciTech Connect

    Litos, Michael; Hogan, Mark

    2014-11-05

    Researchers at SLAC explain how they use plasma wakefields to accelerate bunches of electrons to very high energies over only a short distance. Their experiments offer a possible path for the future of particle accelerators.

  3. Improved plasma accelerator

    NASA Technical Reports Server (NTRS)

    Cheng, D. Y.

    1971-01-01

    Converging, coaxial accelerator electrode configuration operates in vacuum as plasma gun. Plasma forms by periodic injections of high pressure gas that is ionized by electrical discharges. Deflagration mode of discharge provides acceleration, and converging contours of plasma gun provide focusing.

  4. Accelerator Technology Division

    NASA Astrophysics Data System (ADS)

    1992-04-01

    In fiscal year (FY) 1991, the Accelerator Technology (AT) division continued fulfilling its mission to pursue accelerator science and technology and to develop new accelerator concepts for application to research, defense, energy, industry, and other areas of national interest. This report discusses the following programs: The Ground Test Accelerator Program; APLE Free-Electron Laser Program; Accelerator Transmutation of Waste; JAERI, OMEGA Project, and Intense Neutron Source for Materials Testing; Advanced Free-Electron Laser Initiative; Superconducting Super Collider; The High-Power Microwave Program; (Phi) Factory Collaboration; Neutral Particle Beam Power System Highlights; Accelerator Physics and Special Projects; Magnetic Optics and Beam Diagnostics; Accelerator Design and Engineering; Radio-Frequency Technology; Free-Electron Laser Technology; Accelerator Controls and Automation; Very High-Power Microwave Sources and Effects; and GTA Installation, Commissioning, and Operations.

  5. Accelerators, Colliders, and Snakes

    NASA Astrophysics Data System (ADS)

    Courant, Ernest D.

    2003-12-01

    The author traces his involvement in the evolution of particle accelerators over the past 50 years. He participated in building the first billion-volt accelerator, the Brookhaven Cosmotron, which led to the introduction of the "strong-focusing" method that has in turn led to the very large accelerators and colliders of the present day. The problems of acceleration of spin-polarized protons are also addressed, with discussions of depolarizing resonances and "Siberian snakes" as a technique for mitigating these resonances.

  6. Abnormal white matter properties in adolescent girls with anorexia nervosa.

    PubMed

    Travis, Katherine E; Golden, Neville H; Feldman, Heidi M; Solomon, Murray; Nguyen, Jenny; Mezer, Aviv; Yeatman, Jason D; Dougherty, Robert F

    2015-01-01

    Anorexia nervosa (AN) is a serious eating disorder that typically emerges during adolescence and occurs most frequently in females. To date, very few studies have investigated the possible impact of AN on white matter tissue properties during adolescence, when white matter is still developing. The present study evaluated white matter tissue properties in adolescent girls with AN using diffusion MRI with tractography and T1 relaxometry to measure R1 (1/T1), an index of myelin content. Fifteen adolescent girls with AN (mean age = 16.6 years ± 1.4) were compared to fifteen age-matched girls with normal weight and eating behaviors (mean age = 17.1 years ± 1.3). We identified and segmented 9 bilateral cerebral tracts (18) and 8 callosal fiber tracts in each participant's brain (26 total). Tract profiles were generated by computing measures for fractional anisotropy (FA) and R1 along the trajectory of each tract. Compared to controls, FA in the AN group was significantly decreased in 4 of 26 white matter tracts and significantly increased in 2 of 26 white matter tracts. R1 was significantly decreased in the AN group compared to controls in 11 of 26 white matter tracts. Reduced FA in combination with reduced R1 suggests that the observed white matter differences in AN are likely due to reductions in myelin content. For the majority of tracts, group differences in FA and R1 did not occur within the same tract. The present findings have important implications for understanding the neurobiological factors underlying white matter changes associated with AN and invite further investigations examining associations between white matter properties and specific physiological, cognitive, social, or emotional functions affected in AN.

  7. Abnormal white matter properties in adolescent girls with anorexia nervosa

    PubMed Central

    Travis, Katherine E.; Golden, Neville H.; Feldman, Heidi M.; Solomon, Murray; Nguyen, Jenny; Mezer, Aviv; Yeatman, Jason D.; Dougherty, Robert F.

    2015-01-01

    Anorexia nervosa (AN) is a serious eating disorder that typically emerges during adolescence and occurs most frequently in females. To date, very few studies have investigated the possible impact of AN on white matter tissue properties during adolescence, when white matter is still developing. The present study evaluated white matter tissue properties in adolescent girls with AN using diffusion MRI with tractography and T1 relaxometry to measure R1 (1/T1), an index of myelin content. Fifteen adolescent girls with AN (mean age = 16.6 years ± 1.4) were compared to fifteen age-matched girls with normal weight and eating behaviors (mean age = 17.1 years ± 1.3). We identified and segmented 9 bilateral cerebral tracts (18) and 8 callosal fiber tracts in each participant's brain (26 total). Tract profiles were generated by computing measures for fractional anisotropy (FA) and R1 along the trajectory of each tract. Compared to controls, FA in the AN group was significantly decreased in 4 of 26 white matter tracts and significantly increased in 2 of 26 white matter tracts. R1 was significantly decreased in the AN group compared to controls in 11 of 26 white matter tracts. Reduced FA in combination with reduced R1 suggests that the observed white matter differences in AN are likely due to reductions in myelin content. For the majority of tracts, group differences in FA and R1 did not occur within the same tract. The present findings have important implications for understanding the neurobiological factors underlying white matter changes associated with AN and invite further investigations examining associations between white matter properties and specific physiological, cognitive, social, or emotional functions affected in AN. PMID:26740918

  8. Magnetic Resonance investigation into the mechanisms involved in the development of high-altitude cerebral edema

    PubMed Central

    Sagoo, Ravjit S; Hutchinson, Charles E; Wright, Alex; Handford, Charles; Parsons, Helen; Sherwood, Victoria; Wayte, Sarah; Nagaraja, Sanjoy; Ng’Andwe, Eddie; Wilson, Mark H

    2016-01-01

    Rapid ascent to high altitude commonly results in acute mountain sickness, and on occasion potentially fatal high-altitude cerebral edema. The exact pathophysiological mechanisms behind these syndromes remain to be determined. We report a study in which 12 subjects were exposed to a FiO2 = 0.12 for 22 h and underwent serial magnetic resonance imaging sequences to enable measurement of middle cerebral artery velocity, flow and diameter, and brain parenchymal, cerebrospinal fluid and cerebral venous volumes. Ten subjects completed 22 h and most developed symptoms of acute mountain sickness (mean Lake Louise Score 5.4; p < 0.001 vs. baseline). Cerebral oxygen delivery was maintained by an increase in middle cerebral artery velocity and diameter (first 6 h). There appeared to be venocompression at the level of the small, deep cerebral veins (116 cm3 at 2 h to 97 cm3 at 22 h; p < 0.05). Brain white matter volume increased over the 22-h period (574 ml to 587 ml; p < 0.001) and correlated with cumulative Lake Louise scores at 22 h (p < 0.05). We conclude that cerebral oxygen delivery was maintained by increased arterial inflow and this preceded the development of cerebral edema. Venous outflow restriction appeared to play a contributory role in the formation of cerebral edema, a novel feature that has not been observed previously. PMID:26746867

  9. Acceleration: It's Elementary

    ERIC Educational Resources Information Center

    Willis, Mariam

    2012-01-01

    Acceleration is one tool for providing high-ability students the opportunity to learn something new every day. Some people talk about acceleration as taking a student out of step. In actuality, what one is doing is putting a student in step with the right curriculum. Whole-grade acceleration, also called grade-skipping, usually happens between…

  10. Angular Acceleration without Torque?

    ERIC Educational Resources Information Center

    Kaufman, Richard D.

    2012-01-01

    Hardly. Just as Robert Johns qualitatively describes angular acceleration by an internal force in his article "Acceleration Without Force?" here we will extend the discussion to consider angular acceleration by an internal torque. As we will see, this internal torque is due to an internal force acting at a distance from an instantaneous center.

  11. Accelerated test design

    NASA Technical Reports Server (NTRS)

    Mcdermott, P. P.

    1980-01-01

    The design of an accelerated life test program for electric batteries is discussed. A number of observations and suggestions on the procedures and objectives for conducting an accelerated life test program are presented. Equations based on nonlinear regression analysis for predicting the accelerated life test parameters are discussed.

  12. Restricted Arm Swing Affects Gait Stability and Increased Walking Speed Alters Trunk Movements in Children with Cerebral Palsy

    PubMed Central

    Delabastita, Tijs; Desloovere, Kaat; Meyns, Pieter

    2016-01-01

    Observational research suggests that in children with cerebral palsy, the altered arm swing is linked to instability during walking. Therefore, the current study investigates whether children with cerebral palsy use their arms more than typically developing children, to enhance gait stability. Evidence also suggests an influence of walking speed on gait stability. Moreover, previous research highlighted a link between walking speed and arm swing. Hence, the experiment aimed to explore differences between typically developing children and children with cerebral palsy taking into account the combined influence of restricting arm swing and increasing walking speed on gait stability. Spatiotemporal gait characteristics, trunk movement parameters and margins of stability were obtained using three dimensional gait analysis to assess gait stability of 26 children with cerebral palsy and 24 typically developing children. Four walking conditions were evaluated: (i) free arm swing and preferred walking speed; (ii) restricted arm swing and preferred walking speed; (iii) free arm swing and high walking speed; and (iv) restricted arm swing and high walking speed. Double support time and trunk acceleration variability increased more when arm swing was restricted in children with bilateral cerebral palsy compared to typically developing children and children with unilateral cerebral palsy. Trunk sway velocity increased more when walking speed was increased in children with unilateral cerebral palsy compared to children with bilateral cerebral palsy and typically developing children and in children with bilateral cerebral palsy compared to typically developing children. Trunk sway velocity increased more when both arm swing was restricted and walking speed was increased in children with bilateral cerebral palsy compared to typically developing children. It is proposed that facilitating arm swing during gait rehabilitation can improve gait stability and decrease trunk movements in

  13. Restricted Arm Swing Affects Gait Stability and Increased Walking Speed Alters Trunk Movements in Children with Cerebral Palsy.

    PubMed

    Delabastita, Tijs; Desloovere, Kaat; Meyns, Pieter

    2016-01-01

    Observational research suggests that in children with cerebral palsy, the altered arm swing is linked to instability during walking. Therefore, the current study investigates whether children with cerebral palsy use their arms more than typically developing children, to enhance gait stability. Evidence also suggests an influence of walking speed on gait stability. Moreover, previous research highlighted a link between walking speed and arm swing. Hence, the experiment aimed to explore differences between typically developing children and children with cerebral palsy taking into account the combined influence of restricting arm swing and increasing walking speed on gait stability. Spatiotemporal gait characteristics, trunk movement parameters and margins of stability were obtained using three dimensional gait analysis to assess gait stability of 26 children with cerebral palsy and 24 typically developing children. Four walking conditions were evaluated: (i) free arm swing and preferred walking speed; (ii) restricted arm swing and preferred walking speed; (iii) free arm swing and high walking speed; and (iv) restricted arm swing and high walking speed. Double support time and trunk acceleration variability increased more when arm swing was restricted in children with bilateral cerebral palsy compared to typically developing children and children with unilateral cerebral palsy. Trunk sway velocity increased more when walking speed was increased in children with unilateral cerebral palsy compared to children with bilateral cerebral palsy and typically developing children and in children with bilateral cerebral palsy compared to typically developing children. Trunk sway velocity increased more when both arm swing was restricted and walking speed was increased in children with bilateral cerebral palsy compared to typically developing children. It is proposed that facilitating arm swing during gait rehabilitation can improve gait stability and decrease trunk movements in

  14. Astrometric Binaries: White Dwarfs?

    NASA Astrophysics Data System (ADS)

    Oliversen, Nancy A.

    We propose to observe a selection of astrometric or spectroscopicastrometric binaries nearer than about 20 pc with unseen low mass companions. Systems of this type are important for determining the luminosity function of low mass stars (white dwarfs and very late main sequence M stars), and their contribution to the total mass of the galaxy. Systems of this type are also important because the low mass, invisible companions are potential candidates in the search for planets. Our target list is selected primarily from the list of 31 astrometric binaries near the sun by Lippincott (1978, Space Sci. Rev., 22, 153), with additional candidates from recent observations by Kamper. The elimination of stars with previous IUE observations, red companions resolved by infrared speckle interferometry, or primaries later than M1 (because if white dwarf companions are present they should have been detected in the visible region) reduces the list to 5 targets which need further information. IUE SWP low dispersion observations of these targets will show clearly whether the remaining unseen companions are white dwarfs, thus eliminating very cool main sequence stars or planets. This is also important in providing complete statistical information about the nearest stars. The discovery of a white dwarf in such a nearby system would provide important additional information about the masses of white dwarfs. Recent results by Greenstein (1986, A. J., 92, 859) from binary systems containing white dwarfs imply that 80% of such systems are as yet undetected. The preference of binaries for companions of approximately equal mass makes the Lippincott-Kamper list of A through K primaries with unseen companions a good one to use to search for white dwarfs. The mass and light dominance of the current primary over the white dwarf in the visible makes ultraviolet observations essential to obtain an accurate census of white dwarf binaries.

  15. Investigation of emittance growth in the White Horse beam

    SciTech Connect

    Jones, M.E.; Lee, H.; Lemons, D.S.

    1984-01-01

    The equilibrium and stability of the neutral gas transport section of the White Horse beam accelerator is studied. It is found that the beam should be unstable from the two-stream instability and from beam-excited ion-acoustic waves, with the latter being a possible source of emittance growth in the beam. 11 references, 16 figures, 1 table.

  16. Hypermedicalization in White Noise.

    PubMed

    Benson, Josef

    2015-09-01

    The Nazis hijacked Germany's medical establishment and appropriated medical language to hegemonize their ideology. In White Noise, shifting medical information stifles the public into docility. In Nazi Germany the primacy of language and medical authority magnified the importance of academic doctors. The muddling of identities caused complex insecurities and the need for psychological doubles. In White Noise, Professor Gladney is driven by professional insecurities to enact a double in Murray. Through the manipulation of language and medical overreach the U.S., exemplified in the novel White Noise, has become a hypermedicalized society where the spirit of the Hippocratic Oath has eroded.

  17. Cerebral Arterial Fenestrations

    PubMed Central

    Cooke, Daniel L; Stout, Charles E; Kim, Warren T; Kansagra, Akash P; Yu, John Paul; Gu, Amy; Jewell, Nicholas P; Hetts, Steven W; Higashida, Randall T; Dowd, Christopher F; Halbach, Van V

    2014-01-01

    Summary Arterial fenestrations are an anatomic variant with indeterminate significance. Given the controversy surrounding fenestrations we sought their prevalence within our practice along with their association with other cerebrovascular anomalies. We retrospectively reviewed 10,927 patients undergoing digital subtraction angiography between 1992 and 2011. Dictated reports were searched for the terms “fenestration” or “fenestrated” with images reviewed for relevance, yielding 228 unique cases. A Medline database search from February 1964 to January 2013 generated 304 citations, 127 cases of which were selected for analysis. Cerebral arterial fenestrations were identified in 228 patients (2.1%). At least one aneurysm was noted in 60.5% of patients, with an aneurysm arising from the fenestration in 19.6% of patients. Aneurysmal subarachnoid hemorrhage or non-aneurysmal subarachnoid hemorrhage were present in 60.1% and 15.8%, respectively. For the subset of patients with an aneurysm arising directly from a fenestration relative to those patients with an aneurysm not immediately associated with a fenestration, the prevalence of aneurysmal subarachnoid hemorrhage was 66.7% vs. 58.6% (p = 0.58). Fenestrations were more often within the posterior circulation (73.2%) than the anterior circulation (24.6%), though there was no difference in the prevalence of aneurysms within these groups (61.1% vs. 60.7%, p = 1.0). Cerebral arterial fenestrations are an anatomic variant more often manifesting at the anterior communicating arterial complex and basilar artery and with no definite pathological relationship with aneurysms. PMID:24976087

  18. [A comparative study of antistroke activity of the new drug "cerebral" and its fractions in rats].

    PubMed

    Makarenko, A N; Kositsin, N S; Nazimov, I V; Svinov, M M; Goloborod'ko, E V; Pasikova, N V

    2005-01-01

    The effect of the new drug "cerebral" and its fractions 1-3 on the model of bilateral hemorrhagic stroke in white rats was studied with reference to the action of cebrolysin and cerebrolysate-M. With respect to the general functional state, behavioral activity restoration, and morphological data, the most pronounced antistroke action was observed for the cerebral-1 fraction. This fraction was further separated into three subfractions. The most promising test results were obtained for the 1.2 subfraction, which was selected for the further investigation.

  19. [Cardioprotective effect of drugs with antioxidant activity in acute cerebral ischemia].

    PubMed

    Stoliarova, V V

    2001-01-01

    The bioelectric cardiac activity was studied in the experiments on white mice with an acute cerebral blood circulation disorder. It was found that he resulting EEG changes possess a specific character, with the sympathoadrenal system stimulation playing an important role in the acute cerebrocardiac syndrome development. The antioxidant-type agents such as emoxypine (50 mg/kg), mexidol (50 mg/kg), and cytochrome C (10 mg/kg) produce a significant cardioprotective effect in the test animals with experimental cerebral ischemia, which was comparable with the effect of propranolol (obsidane) (0.1 mg/kg).

  20. Cerebral infarct with recurrence of hemolytic-uremic syndrome in a child following renal transplantation.

    PubMed

    Mochon, M; Kaiser, B A; deChadarevian, J P; Polinsky, M S; Baluarte, H J

    1992-11-01

    A white girl with a history of atypical hemolytic-uremic syndrome (HUS) and persistent microangiopathic anemia, and thrombocytopenia for 2 months after the initial presentation at age 7 months, received her first cadaveric renal transplant at age 3 years. During the first 2.5 days post transplant, she developed progressive thrombocytopenia and anemia followed by tonic-clonic seizures and loss of consciousness, secondary to a diffuse cerebral infarction of the left hemisphere. Renal histology showed evidence of glomerular microthrombi and microangiopathy. A large cerebral infarct, previously described in patients during their initial presentation with HUS, presented in our patient as part of the recurrence of the disease post renal transplantation.

  1. Fiber Accelerating Structures

    SciTech Connect

    Hammond, Andrew P.; /Reed Coll. /SLAC

    2010-08-25

    One of the options for future particle accelerators are photonic band gap (PBG) fiber accelerators. PBG fibers are specially designed optical fibers that use lasers to excite an electric field that is used to accelerate electrons. To improve PBG accelerators, the basic parameters of the fiber were tested to maximize defect size and acceleration. Using the program CUDOS, several accelerating modes were found that maximized these parameters for several wavelengths. The design of multiple defects, similar to having closely bound fibers, was studied to find possible coupling or the change of modes. The amount of coupling was found to be dependent on distance separated. For certain distances accelerating coupled modes were found and examined. In addition, several non-periodic fiber structures were examined using CUDOS. The non-periodic fibers produced several interesting results and promised more modes given time to study them in more detail.

  2. High brightness electron accelerator

    DOEpatents

    Sheffield, Richard L.; Carlsten, Bruce E.; Young, Lloyd M.

    1994-01-01

    A compact high brightness linear accelerator is provided for use, e.g., in a free electron laser. The accelerator has a first plurality of acclerating cavities having end walls with four coupling slots for accelerating electrons to high velocities in the absence of quadrupole fields. A second plurality of cavities receives the high velocity electrons for further acceleration, where each of the second cavities has end walls with two coupling slots for acceleration in the absence of dipole fields. The accelerator also includes a first cavity with an extended length to provide for phase matching the electron beam along the accelerating cavities. A solenoid is provided about the photocathode that emits the electons, where the solenoid is configured to provide a substantially uniform magnetic field over the photocathode surface to minimize emittance of the electons as the electrons enter the first cavity.

  3. Cerebral hydatid disease in Britain

    PubMed Central

    Anderson, Milne; Bickerstaff, Edwin R.; Hamilton, J. G.

    1975-01-01

    Two cases of cerebral hydatid disease are described. This condition, acquired by Britons in Britain, is extremely rare as only two similar cases have been reported before. Details of clinical presentation, investigation and treatment are described. Images PMID:1206419

  4. Cerebral emboli of paradoxical origin.

    PubMed

    Jones, H R; Caplan, L R; Come, P C; Swinton, N W; Breslin, D J

    1983-03-01

    A diagnosis of paradoxical cerebral embolus (PCE) was made in five patients aged 31 to 62 years who sustained eight cerebral ischemic events. No patient had evidence of primary carotid system or left heart disease. A probe-patent foramen ovale was the presumed mechanism in four patients, and an unsuspected congenital atrial septal defect was found in the fifth patient. Clinically apparent pulmonary emboli or venous thrombosis preceded the cerebral event in only one instance. Review of the literature reveals a high mortality with PCE. However, careful clinical search for this lesion may be rewarding: four of our five patients survived. One should consider PCE in any patient with cerebral embolus in whom there is no demonstrable left-sided circulatory source. This principle applies particularly if there is concomitant venous thrombosis, pulmonary embolism, or enhanced potential for venous thrombosis due to, for example, morbid obesity, use of hormonal birth control pills, prolonged bed rest (especially postoperatively), or systemic carcinoma.

  5. ESCO White Paper

    EPA Pesticide Factsheets

    EPA developed this white paper to explore energy performance contracting with Energy Service Companies (ESCOs) and its potential to be a best practice for installing solar thermal water heating systems in the commercial and industrial sector.

  6. Distribution System White Papers

    EPA Pesticide Factsheets

    EPA worked with stakeholders and developed a series of white papers on distribution system issues ranked of potentially significant public health concern (see list below) to serve as background material for EPA, expert and stakeholder discussions.

  7. White Lake AOC

    EPA Pesticide Factsheets

    White Lake is in Muskegon County along the eastern shore of Lake Michigan. It was named an Area of Concern on the Great Lakes under the Great Lakes Water Quality Agreement of 1987 and delisted in 2014.

  8. Carpenter in White Room

    NASA Technical Reports Server (NTRS)

    1962-01-01

    Inside Hangar S at the White Room Facility at Cape Canaveral, Florida, Mercury astronaut M. Scott Carpenter examines the honeycomb protective material on the main pressure bulkhead (heat shield) of his Mercury capsule nicknamed 'Aurora 7.'

  9. Pollack Crater's White Rock

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This image of White Rock in Pollack crater was taken by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on February 3, 2007 at 1750 UTC (12:50 p.m. EST), near 8 degrees south latitude, 25 degrees east longitude. The CRISM image was taken in 544 colors covering 0.36-3.92 micrometers, and shows features as small as 40 meters (132 feet) across. The region covered is roughly 20 kilometers (12 miles) long and 10 kilometers (6 miles) wide at its narrowest point.

    First imaged by the Mariner 9 spacecraft in 1972, the enigmatic group of wind-eroded ridges known as White Rock has been the subject of many subsequent investigations. White Rock is located on the floor of Pollack Crater in the Sinus Sabaeus region of Mars. It measures some 15 by 18 kilometers (9 by 11 miles) and was named for its light-colored appearance. In contrast-enhanced images, the feature's higher albedo or reflectivity compared with the darker material on the floor of the crater makes it appear white. In reality, White Rock has a dull, reddish color more akin to Martian dust. This higher albedo as well as its location in a topographic low suggested to some researchers that White Rock may be an eroded remnant of an ancient lake deposit. As water in a desert lake on Earth evaporates, it leaves behind white-colored salts that it leached or dissolved out of the surrounding terrain. These salt deposits may include carbonates, sulfates, and chlorides.

    In 2001, the Thermal Emission Spectrometer (TES) on NASA's Mars Global Surveyor measured White Rock and found no obvious signature of carbonates or sulfates, or any other indication that White Rock holds evaporite minerals. Instead, it found Martian dust.

    CRISM's challenge was to obtain greater detail of White Rock's mineralogical composition and how it formed. The instrument operates at a different wavelength range than TES, giving it greater sensitivity to carbonate, sulfate and phyllosilicate (clay-like) minerals. It also

  10. Primary Open Angle Glaucoma is Associated with MR Biomarkers of Cerebral Small Vessel Disease

    PubMed Central

    Mercieca, Karl; Cain, John; Hansen, Thomas; Steeples, Laura; Watkins, Amy; Spencer, Fiona; Jackson, Alan

    2016-01-01

    This prospective study tests the hypotheses that: 1) glaucoma is associated with evidence of cerebral small vessel disease; 2) that imaging biomarkers of cerebral small vessel disease in POAG and NTG will show different characteristics. 12 normal controls, 7 patients with primary open angle glaucoma (POAG) and 9 patients with normal tension glaucoma (NTG) were recruited. Ophthalmological clinical assessment and MR imaging of the brain were performed. MR imaging was used to quantify white matter lesion load, frequency of dilated perivascular spaces (PVS) and abnormalities in cerebral hydrodynamics. Patients with POAG had significantly greater white matter lesion load (p < 0.05), more PVS in the centrum semiovale (p < 0.05) and had higher overall PVS scores than controls (p < 0.05). In the POAG group, optic cup-to-disc ratio (CDR) was positively correlated with deep white matter hyperintensities (R2 = 0.928, p < 0.01). Mean deviation on the Humphrey visual field assessment was negatively correlated with deep white matter lesion load (R2 = −0.840, p < 0.01), total white matter lesion load (R2 = −0.928, p < 0.01) and total PVS (R2 = −0.820, p < 0.01). MR evidence of cerebral small vessel disease is strongly associated with a diagnosis of POAG and with the severity of abnormalities in CDR and visual field. PMID:26923106

  11. White Racial Identity Statuses as Predictors of White Privilege Awareness

    ERIC Educational Resources Information Center

    Hays, Danica G.; Chang, Catherine Y.; Havice, Pamela

    2008-01-01

    This study explored the relationship between White privilege awareness and White racial identity development for 197 counseling trainees. Results indicated that 3 of J. E. Helms's (1984, 1990, 1995) White racial identity statuses (i.e., Contact, Reintegration, and Immersion/Emersian) significantly predicted White privilege awareness. Implications…

  12. Acceleration in astrophysics

    SciTech Connect

    Colgate, S.A.

    1993-12-31

    The origin of cosmic rays and applicable laboratory experiments are discussed. Some of the problems of shock acceleration for the production of cosmic rays are discussed in the context of astrophysical conditions. These are: The presumed unique explanation of the power law spectrum is shown instead to be a universal property of all lossy accelerators; the extraordinary isotropy of cosmic rays and the limited diffusion distances implied by supernova induced shock acceleration requires a more frequent and space-filling source than supernovae; the near perfect adiabaticity of strong hydromagnetic turbulence necessary for reflecting the accelerated particles each doubling in energy roughly 10{sup 5} to {sup 6} scatterings with negligible energy loss seems most unlikely; the evidence for acceleration due to quasi-parallel heliosphere shocks is weak. There is small evidence for the expected strong hydromagnetic turbulence, and instead, only a small number of particles accelerate after only a few shock traversals; the acceleration of electrons in the same collisionless shock that accelerates ions is difficult to reconcile with the theoretical picture of strong hydromagnetic turbulence that reflects the ions. The hydromagnetic turbulence will appear adiabatic to the electrons at their much higher Larmor frequency and so the electrons should not be scattered incoherently as they must be for acceleration. Therefore the electrons must be accelerated by a different mechanism. This is unsatisfactory, because wherever electrons are accelerated these sites, observed in radio emission, may accelerate ions more favorably. The acceleration is coherent provided the reconnection is coherent, in which case the total flux, as for example of collimated radio sources, predicts single charge accelerated energies much greater than observed.

  13. Robotics Strategy White Paper

    DTIC Science & Technology

    2009-03-19

    VIRGINIA 23651-1087 REPlY TO A1Tl!NTlON OF ATFC-DS 19 MEMORANDUM FOR SEE DISTRIBUTION SUBJECT: Robotics Strategy White Paper 1. The enclosed... Robotics Strategy White Paper is the result of a collaborative effort between the U.S. Anny Training and Doctrine Command (TRADOC) and the Tank-Automotive...Research, Development and Engineering Center (TARDEC). This paper builds on a confederated Anny robotics "strategy" that is described by senior leader

  14. Cerebral ganglioglioma. A Golgi study.

    PubMed

    Ferrer, I; Ribalta, T; Digon, E; Acebes, J

    1983-01-01

    The morphological characteristics of neurons revealed by Golgi's method are reported in a case of cerebral ganglioglioma. Spindle-shaped (leptodendritic) neurons and radiated type I neurons form the bulk of this tumour. According to Ramon-Moliner (1968) isodendritic neurons (both leptodendritic and radiate type I) are philogenetically primitive cells and differ greatly from those observed in most of the deep cerebral nuclei of the mammalian's brain.

  15. Resource Allocation in Cerebral Specialization.

    DTIC Science & Technology

    1980-01-01

    of this multiple-resources view. EXTENSION OF THE THEORY TO THE TWO CEREBRAL HEMISPHERES Since the anatomical division of the brain invites...performance differences between the hemispheres (e.g., right-handed males with no familial history of left- handedness who use a normal rather than an...G. Beaumont (Eds.), Hemisphere function in the human rain.. New York: Halstead Press, 1974. Kinsbourne, M. The cerebral basis of lateral asymmetries

  16. Cerebral Cortex Structure in Prodromal Huntington Disease

    PubMed Central

    Nopoulos, Peggy C.; Aylward, Elizabeth H.; Ross, Christopher A.; Johnson, Hans J.; Magnotta, Vincent A.; Juhl, Andrew R.; Pierson, Ronald K.; Mills, James; Langbehn, Douglas R.; Paulsen, Jane S.

    2010-01-01

    Neuroimaging studies of subjects who are gene-expanded for Huntington Disease, but not yet diagnosed (termed prodromal HD), report that the cortex is “spared,” despite the decrement in striatal and cerebral white-matter volume. Measurement of whole-cortex volume can mask more subtle, but potentially clinically relevant regional changes in volume, thinning, or surface area. The current study addressed this limitation by evaluating cortical morphology of 523 prodromal HD subjects. Participants included 693 individuals enrolled in the PREDICT-HD protocol. Of these participants, 523 carried the HD gene mutation (prodromal HD group); the remaining 170 were non gene-expanded and served as the comparison group. Based on age and CAG repeat length, gene-expanded subjects were categorized as “Far from onset,” “Midway to onset,” “Near onset,” and “already diagnosed.” MRI scans were processed using FreeSurfer. Cortical volume, thickness, and surface area were not significantly different between the Far from onset group and controls. However, beginning in the Midway to onset group, the cortex showed significant volume decrement, affecting most the posterior and superior cerebral regions. This pattern progressed when evaluating the groups further into the disease process. Areas that remained mostly unaffected included ventral and medial regions of the frontal and temporal cortex. Morphologic changes were mostly in thinning as surface area did not substantially change in most regions. Early in the course of HD, the cortex shows changes that are manifest as cortical thinning and are most robust in the posterior and superior regions of the cerebrum. PMID:20688164

  17. White matter integrity in small vessel disease is related to cognition

    PubMed Central

    Tuladhar, Anil M.; van Norden, Anouk G.W.; de Laat, Karlijn F.; Zwiers, Marcel P.; van Dijk, Ewoud J.; Norris, David G.; de Leeuw, Frank-Erik

    2015-01-01

    Cerebral small vessel disease, including white matter hyperintensities (WMH) and lacunes of presumed vascular origin, is common in elderly people and is related to cognitive impairment and dementia. One possible mechanism could be the disruption of white matter tracts (both within WMH and normal-appearing white matter) that connect distributed brain regions involved in cognitive functions. Here, we investigated the relation between microstructural integrity of the white matter and cognitive functions in patients with small vessel disease. The Radboud University Nijmegen Diffusion tensor and Magnetic resonance Cohort study is a prospective cohort study among 444 independently living, non-demented elderly with cerebral small vessel disease, aged between 5500 and 85 years. All subjects underwent magnetic resonance imaging and diffusion tensor imaging scanning and an extensive neuropsychological assessment. We showed that loss of microstructural integrity of the white matter at specific locations was related to specific cognitive disturbances, which was mainly located in the normal-appearing white matter (p < 0.05, FWE-corrected for multiple comparisons). The microstructural integrity in the genu and splenium showed the highest significant relation with global cognitive function and executive functions, in the cingulum bundle with verbal memory performance. Associations between diffusion tensor imaging parameters and most cognitive domains remained present after adjustment for WMH and lacunes. In conclusion, cognitive disturbances in subjects with cerebral small vessel disease are related to microstructural integrity of multiple white matter fibers (within WMH and normal-appearing white matter) connecting different cortical and subcortical regions. PMID:25737960

  18. Therapeutic implications of melatonin in cerebral edema.

    PubMed

    Rathnasamy, Gurugirijha; Ling, Eng-Ang; Kaur, Charanjit

    2014-12-01

    Cerebral edema/brain edema refers to the accumulation of fluid in the brain and is one of the fatal conditions that require immediate medical attention. Cerebral edema develops as a consequence of cerebral trauma, cerebral infarction, hemorrhages, abscess, tumor, hypoxia, and other toxic or metabolic factors. Based on the causative factors cerebral edema is differentiated into cytotoxic cerebral edema, vasogenic cerebral edema, osmotic and interstitial cerebral edema. Treatment of cerebral edema depends on timely diagnosis and medical assistance. Pragmatic treatment strategies such as antihypertensive medications, nonsteroidal anti-inflammatory drugs, barbiturates, steroids, glutamate and N-methyl-D-aspartate receptor antagonists and trometamol are used in clinical practice. Although the above mentioned treatment approaches are being used, owing to the complexity of the mechanisms involved in cerebral edema, a single therapeutic strategy which could ameliorate cerebral edema is yet to be identified. However, recent experimental studies have suggested that melatonin, a neurohormone produced by the pineal gland, could be an effective alternative for treating cerebral edema. In animal models of stroke, melatonin was not only shown to reduce cerebral edema but also preserved the blood brain barrier. Melatonin's beneficial effects were attributed to its properties, such as being a potent anti-oxidant, and its ability to cross the blood brain barrier within minutes after its administration. This review summarizes the beneficial effects of melatonin when used for treating cerebral edema.

  19. Pattern of normal age-related regional differences in white matter microstructure is modified by vascular risk.

    PubMed

    Kennedy, Kristen M; Raz, Naftali

    2009-11-10

    Even successful aging is associated with regional brain shrinkage and deterioration of the cerebral white matter. Aging also brings about an increase in vascular risk, and vascular impairment may be a potential mechanism behind the observed patterns of aging. The goals of this study were to characterize the normal age differences in white matter integrity in several brain regions across the adult life span and to assess the modifying effect of vascular risk on the observed pattern of regional white matter integrity. We estimated fractional anisotropy and diffusivity of white matter in nine cerebral regions of interest in 77 healthy adults (19-84 years old). There was a widespread reduction of white matter anisotropy with age, and prefrontal and occipital regions evidenced the greatest age-related differences. Diffusivity increased with age, and the magnitude of age differences increased beginning with the middle of the fifth decade. Vascular risk factors modified age differences in white matter integrity. Clinically diagnosed and treated arterial hypertension was associated with reduced white matter anisotropy and increased diffusivity beyond the effects of age. In the normotensive participants, elevation of arterial pulse pressure (a surrogate of arterial stiffness) was linked to deterioration of the white matter integrity in the frontal regions. Although the causal role of vascular risk in brain aging is unclear, the observed pattern of effects suggests that vascular risk may drive the expansion of age-related white matter damage from anterior to posterior regions.

  20. Age-related decline in oligodendrogenesis retards white matter repair in mice

    PubMed Central

    Miyamoto, Nobukazu; Pham, Loc-Duyen D.; Hayakawa, Kazuhide; Matsuzaki, Toshinori; Seo, Ji Hae; Magnain, Caroline; Ayata, Cenk; Kim, Kyu-Won; Boas, David; Lo, Eng H.; Arai, Ken

    2013-01-01

    Background/Purpose Aging is one of the major risk factors for white matter injury in cerebrovascular disease. However, the effects of age on the mechanisms of injury/repair in white matter remain to be fully elucidated. Here, we ask if compared to young brains, white matter regions in older brains may be more vulnerable in part due to decreased rates of compensatory oligodendrogenesis after injury. Methods A mouse model of prolonged cerebral hypoperfusion was prepared by bilateral common carotid artery stenosis in 2-month and 8-month old mice. Matching in vitro studies were performed by subjecting oligodendrocyte precursor cells (OPCs) to sub-lethal 7-day CoCl2 treatment to induce chemical hypoxic stress. Results Baseline myelin density in the corpus callosum was similar in 2-month and 8-month old mice. But after induction of prolonged cerebral hypoperfusion, older mice showed more severe white matter injury together with worse deficits in working memory. The numbers of newborn oligodendrocytes and their precursors were increased by cerebral hypoperfusion in young mice, whereas these endogenous responses were significantly dampened in older mice. Defects in CREB signaling may be involved because activating CREB with the type-III phosphodiesterase inhibitor cilostazol in older mice restored the differentiation of OPCs, alleviated myelin loss and improved cognitive dysfunction during cerebral hypoperfusion. Cell culture systems confirmed that cilostazol promoted the differentiation of OPCs. Conclusions An age-related decline in CREB-mediated oligodendrogenesis may compromise endogenous white matter repair mechanisms, and therefore, drugs that activate CREB signaling provide a potential therapeutic approach for treating white matter injury in aging brains. PMID:23881957

  1. Metabolic, inflammatory, and microvascular determinants of white matter disease and cognitive decline

    PubMed Central

    Wang, Maggie; Norman, Jennifer E; Srinivasan, Vivek J; Rutledge, John C

    2016-01-01

    White Matter Disease is increasingly being recognized as an important cause of cognitive decline and dementia. Various investigations have linked chronic diet-related conditions to the development of white matter lesions, which appear as white matter hyperintensities on T2-weighted magnetic resonance imaging (MRI) scans of the brain. Thus, it can be postulated that the metabolic, inflammatory, and microvascular changes accompanying a western diet, hyperlipidemia, hypertension, and diabetes mellitus type II (DMII) are potential mediators in the development and progression of white matter disease, which in turn contributes to the development and progression of cognitive decline. This review will examine evidence for potential metabolic, inflammatory, and microvascular determinants of white matter disease and cognitive decline. Specifically, we will focus on the effects of altered insulin signaling in diabetes, obesity-induced oxidative stress, neuroinflammation, arterial stiffness due to hypertension, ischemia secondary to cerebral small vessel disease, and blood brain barrier disturbances. PMID:28078193

  2. Low White Blood Cell Count

    MedlinePlus

    Symptoms Low white blood cell count By Mayo Clinic Staff A low white blood cell count (leukopenia) is a decrease in disease-fighting cells ( ... a decrease in a certain type of white blood cell (neutrophil). The definition of low white blood cell ...

  3. An introduction to acceleration mechanisms

    SciTech Connect

    Palmer, R.B.

    1987-05-01

    This paper discusses the acceleration of charged particles by electromagnetic fields, i.e., by fields that are produced by the motion of other charged particles driven by some power source. The mechanisms that are discussed include: Ponderamotive Forces, Acceleration, Plasma Beat Wave Acceleration, Inverse Free Electron Laser Acceleration, Inverse Cerenkov Acceleration, Gravity Acceleration, 2D Linac Acceleration and Conventional Iris Loaded Linac Structure Acceleration. (LSP)

  4. Lifetime Estimation of High Power White LEDs

    NASA Astrophysics Data System (ADS)

    Ishizaki, Shinya; Kimura, Hideyoshi; Sugimoto, Masaru

    We have developed a high power and long lifetime white LED module which can be used in general lighting applications. Since the materials in the package are very robust at high temperatures, the device can be operated at junction temperatures (Tj) over 250°C. Moreover, the thermal resistance of the package is less than 20°C/W. Therefore the device can be operated at input power as high as 2.4 W, making it possible to shorten the duration of accelerated lifetime tests. An acceleration ratio greater than 100 has been achieved. Assuming a thermally activated degradation process and applying the Arrhenius model, the LED chip lifetime (defined as a 50% reduction in luminous flux) is determined to be 40,000 hours for a Tj of 130°C. The activation energy of the degradation process was determined to be 1.55 eV.

  5. Schooling in Times of Acceleration

    ERIC Educational Resources Information Center

    Buddeberg, Magdalena; Hornberg, Sabine

    2017-01-01

    Modern societies are characterised by forms of acceleration, which influence social processes. Sociologist Hartmut Rosa has systematised temporal structures by focusing on three categories of social acceleration: technical acceleration, acceleration of social change, and acceleration of the pace of life. All three processes of acceleration are…

  6. Monitoring Cerebral Oxygenation in Neonates: An Update

    PubMed Central

    Dix, Laura Marie Louise; van Bel, Frank; Lemmers, Petra Maria Anna

    2017-01-01

    Cerebral oxygenation is not always reflected by systemic arterial oxygenation. Therefore, regional cerebral oxygen saturation (rScO2) monitoring with near-infrared spectroscopy (NIRS) is of added value in neonatal intensive care. rScO2 represents oxygen supply to the brain, while cerebral fractional tissue oxygen extraction, which is the ratio between rScO2 and systemic arterial oxygen saturation, reflects cerebral oxygen utilization. The balance between oxygen supply and utilization provides insight in neonatal cerebral (patho-)physiology. This review highlights the potential and limitations of cerebral oxygenation monitoring with NIRS in the neonatal intensive care unit. PMID:28352624

  7. Uniformly accelerated black holes

    NASA Astrophysics Data System (ADS)

    Letelier, Patricio S.; Oliveira, Samuel R.

    2001-09-01

    The static and stationary C metric are examined in a generic framework and their interpretations studied in some detail, especially those with two event horizons, one for the black hole and another for the acceleration. We find that (i) the spacetime of an accelerated static black hole is plagued by either conical singularities or a lack of smoothness and compactness of the black hole horizon, (ii) by using standard black hole thermodynamics we show that accelerated black holes have a higher Hawking temperature than Unruh temperature of the accelerated frame, and (iii) the usual upper bound on the product of the mass and acceleration parameters (<1/27) is just a coordinate artifact. The main results are extended to accelerated rotating black holes with no significant changes.

  8. The Dielectric Wall Accelerator

    SciTech Connect

    Caporaso, George J.; Chen, Yu-Jiuan; Sampayan, Stephen E.

    2009-01-01

    The Dielectric Wall Accelerator (DWA), a class of induction accelerators, employs a novel insulating beam tube to impress a longitudinal electric field on a bunch of charged particles. The surface flashover characteristics of this tube may permit the attainment of accelerating gradients on the order of 100 MV/m for accelerating pulses on the order of a nanosecond in duration. A virtual traveling wave of excitation along the tube is produced at any desired speed by controlling the timing of pulse generating modules that supply a tangential electric field to the tube wall. Because of the ability to control the speed of this virtual wave, the accelerator is capable of handling any charge to mass ratio particle; hence it can be used for electrons, protons and any ion. The accelerator architectures, key technologies and development challenges will be described.

  9. Esophageal eosinophilia in pediatric patients with cerebral palsy

    PubMed Central

    de Nápolis, Ana Carolina Ramos; Alves, Flavia Araujo; Rezende, Erica Rodrigues Mariano de Almeida; Segundo, Gesmar Rodrigues Silva

    2015-01-01

    ABSTRACT Objective: To describe the clinical picture, test results, and clinical evolution of patients with cerebral palsy associated with diagnosis of eosinophilic esophagitis, monitored at tertiary centre. Methods: Cross-sectional, retrospective and descriptive study that evaluated the medical records data of pediatric patients with diagnosis of cerebral palsy and eosinophilic esophagitis in a tertiary center of pediatric gastroenterology between August 2005 and August 2013. Results: Seven out of 131 patients with cerebral palsy had the diagnosis of eosinophilic esophagitis. The mean age at diagnosis of eosinophilic esophagitis was 52.3 months and the mean number of eosinophils in esophagus was 35 per high-power field. Symptoms more frequent were recurrent vomiting and disphagia. Endoscopic alterations found were mucosal thickening, vertical lines, mucosal opacificacion and white plaques. Conclusion: The frequency of eosinophilic esophagitis found was higher than in general pediatric population. The investigation of eosinophilic esophagitis should be done regularly in those patients, once this entity could overlap other gastrointestinal diseases. PMID:26154544

  10. Cerebral Microbleeds: A Review of Clinical, Genetic, and Neuroimaging Associations

    PubMed Central

    Yates, Paul A.; Villemagne, Victor L.; Ellis, Kathryn A.; Desmond, Patricia M.; Masters, Colin L.; Rowe, Christopher C.

    2013-01-01

    Cerebral microbleeds (microbleeds) are small, punctuate hypointense lesions seen in T2* Gradient-Recall Echo (GRE) and Susceptibility-Weighted (SWI) Magnetic Resonance Imaging (MRI) sequences, corresponding to areas of hemosiderin breakdown products from prior microscopic hemorrhages. They occur in the setting of impaired small vessel integrity, commonly due to either hypertensive vasculopathy or cerebral amyloid angiopathy. Microbleeds are more prevalent in individuals with Alzheimer’s disease (AD) dementia and in those with both ischemic and hemorrhagic stroke. However they are also found in asymptomatic individuals, with increasing prevalence with age, particularly in carriers of the Apolipoprotein (APOE) ε4 allele. Other neuroimaging findings that have been linked with microbleeds include lacunar infarcts and white matter hyperintensities on MRI, and increased cerebral β-amyloid burden using 11C-PiB Positron Emission Tomography. The presence of microbleeds has been suggested to confer increased risk of incident intracerebral hemorrhage – particularly in the setting of anticoagulation – and of complications of immunotherapy for AD. Prospective data regarding the natural history and sequelae of microbleeds are currently limited, however there is a growing evidence base that will serve to inform clinical decision-making in the future. PMID:24432010

  11. Encephaloduroarteriosynangiosis for cerebral proliferative angiopathy with cerebral ischemia.

    PubMed

    Kono, Kenichi; Terada, Tomoaki

    2014-12-01

    Cerebral proliferative angiopathy (CPA) is a rare clinical entity. This disorder is characterized by diffuse vascular abnormalities with intermingled normal brain parenchyma, and is differentiated from classic arteriovenous malformations. The management of CPA in patients presenting with nonhemorrhagic neurological deficits due to cerebral ischemia is challenging and controversial. The authors report a case of adult CPA with cerebral ischemia in which neurological deficits were improved after encephaloduroarteriosynangiosis (EDAS). A 28-year-old man presented with epilepsy. Magnetic resonance imaging and angiography showed a diffuse vascular network (CPA) in the right hemisphere. Antiepileptic medications were administered. Four years after the initial onset of epilepsy, the patient's left-hand grip strength gradually decreased over the course of 1 year. The MRI studies showed no infarcts, but technetium-99m-labeled ethyl cysteinate dimer ((99m)Tc-ECD) SPECT studies obtained with acetazolamide challenge demonstrated hypoperfusion and severely impaired cerebrovascular reactivity over the affected hemisphere. This suggested that the patient's neurological deficits were associated with cerebral ischemia. The authors performed EDAS for cerebral ischemia, and the patient's hand grip strength gradually improved after the operation. Follow-up angiography studies obtained 7 months after the operation showed profound neovascularization through the superficial temporal artery and the middle meningeal artery. A SPECT study showed slight improvement of hypoperfusion at the focal region around the right motor area, indicating clinical improvement from the operation. The authors conclude that EDAS may be a treatment option for CPA-related hypoperfusion.

  12. Optically pulsed electron accelerator

    DOEpatents

    Fraser, J.S.; Sheffield, R.L.

    1985-05-20

    An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radiofrequency-powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

  13. Optically pulsed electron accelerator

    DOEpatents

    Fraser, John S.; Sheffield, Richard L.

    1987-01-01

    An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radio frequency powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

  14. ACCELERATION RESPONSIVE SWITCH

    DOEpatents

    Chabrek, A.F.; Maxwell, R.L.

    1963-07-01

    An acceleration-responsive device with dual channel capabilities whereby a first circuit is actuated upon attainment of a predetermined maximum acceleration level and when the acceleration drops to a predetermined minimum acceleriltion level another circuit is actuated is described. A fluid-damped sensing mass slidably mounted in a relatively frictionless manner on a shaft through the intermediation of a ball bushing and biased by an adjustable compression spring provides inertially operated means for actuating the circuits. (AEC)

  15. The foxhole accelerating structure

    SciTech Connect

    Fernow, R.C.; Claus, J.

    1992-07-17

    This report examines some properties of a new type of open accelerating structure. It consists of a series of rectangular cavities, which we call foxholes, joined by a beam channel. The power for accelerating the particles comes from an external radiation source and enters the cavities through their open upper surfaces. Analytic and computer calculations are presented showing that the foxhole is a suitable structure for accelerating relativistic electrons.

  16. [Plasma osmolarity and cerebral volume].

    PubMed

    Boulard, G

    2001-02-01

    Under normal physiological conditions, the osmolarity of extracellular fluids (ECFs) and natremia are controlled by two regulatory mechanisms modulating the water balance and sodium outflow from information collected by the osmoreceptors and baroreceptors, respectively. As well, under normal physiological conditions, water and electrolytes of brain ECFs are secreted by the endothelial cells of brain capillaries. Furthermore, isotonicity is present on both sides of the blood-brain barrier. In the event of systemic osmolarity disorders, water transport subject to osmosis laws occurs at the level of the blood-brain barrier. In the case of plasmatic hyperosmolarity cerebral dehydration is observed, while cerebral edema occurs in the contrary case. However, plasmatic osmolarity disorders have less effect on the cerebral volume when their introduction is slow. Experimentation in acute conditions shows that measured variations of the cerebral water content are lower than calculated variations, thus suggesting the existence of an adaptive mechanism, that is, the cerebral osmoregulation which limits the variation of the volume of brain cells by modulating their osmoactive molecule content. These osmoactive molecules are, on the one hand, the electrolytes, which are early and rapidly mobilized, and, on the other hand, the organic osmoles (amino acids, etc.), whose secretion is slower and delayed. This phenomenon should be taken into account in the treatment of osmolarity disorders. Thus, the related-risk of treatment for natremia disorders is therapeutic reversal of the osmotic gradient at the level of the blood-brain barrier. This reversal, which corresponds to a second osmotic stress, requires the implementation of a new procedure of cerebral osmoregulation in the opposite direction of the preceding one. As successive osmotic stresses decrease the effectiveness of brain osmoregulation, the risk for cerebral dehydration and pontine myelinolysis increases when the treatment

  17. Functional changes in systemic and regional (intracranial) circulation accompanying low accelerations

    NASA Technical Reports Server (NTRS)

    Usachev, V. V.; Shinkarevskaya, I. P.

    1973-01-01

    Functional changes in systemic and cerebral hemodynamics were studied with respect to vestibular stresses. The main types of responses, differing qualitatively with respect to the tolerance of test subjects to low accelerations (particularly to Coriolis accelerations), were established. This is of practical importance in the selection of aircraft and space pilots. The data presented sheds light on the physiological mechanisms of adaptation and disturbed compensation during vestibular stimulation. Further studies in this important field of aerospace medicine are outlined.

  18. Silent ischemic lesion laterality in asymptomatic internal carotid artery stenosis relates to reduced cerebral vasoreactivity

    PubMed Central

    Isozaki, Makoto; Kataoka, Hiroharu; Fukushima, Kazuhito; Ishibashi-Ueda, Hatsue; Yamada, Naoaki; Iida, Hidehiro; Iihara, Koji

    2017-01-01

    Background: We investigated the relationship between silent ischemic lesions, defined as hyperintense lesions on T2-weighted magnetic resonance imaging scans of brain white matter and cerebral hemodynamics (baseline cerebral blood flow and cerebral vasoreactivity). Methods: Between January 2007 and December 2012, 61 patients with asymptomatic internal carotid artery stenosis were evaluated for asymptomatic silent ischemic lesions, acute infarction, and cerebral hemodynamics. Patients were divided into 2 groups based on silent ischemic lesion distribution; the Symmetry group (n = 34) included patients who showed symmetrical distribution of lesions (or had no lesions), and the Asymmetry group (n = 27) included patients with a greater number of lesions in the ipsilateral than that in the contralateral hemisphere. The Asymmetry group was further divided into Internal (n = 15) and External (n = 12) types. Results: Two External-type patients (17%) showed spotty asymptomatic acute infarction in the ipsilateral hemisphere. There were no significant differences in patient characteristics, histopathological findings, vascular risk factors, or cerebral blood flow values between the groups. The mean cerebral vasoreactivity value in the ipsilateral hemisphere for the Internal type was 13.0 ± 15.2% (range: −11.4% to 41.6%), which was significantly lower than values of the contralateral hemisphere (36.7 ± 20.8%; range: 3.9% to 75.7%; P <.01) and ipsilateral hemispheres of the other groups (P <.01). Conclusions: The finding that increased ipsilateral asymmetrical silent ischemic lesions correlated with cerebral vasoreactivity reduction may help predict the risk of cerebral infarction in patients with asymptomatic internal carotid artery stenosis. PMID:28217385

  19. Mutation in the AP4M1 Gene Provides a Model for Neuroaxonal Injury in Cerebral Palsy

    PubMed Central

    Verkerk, Annemieke J.M.H.; Schot, Rachel; Dumee, Belinda; Schellekens, Karlijn; Swagemakers, Sigrid; Bertoli-Avella, Aida M.; Lequin, Maarten H.; Dudink, Jeroen; Govaert, Paul; van Zwol, A.L.; Hirst, Jennifer; Wessels, Marja W.; Catsman-Berrevoets, Coriene; Verheijen, Frans W.; de Graaff, Esther; de Coo, Irenaeus F.M.; Kros, Johan M.; Willemsen, Rob; Willems, Patrick J.; van der Spek, Peter J.; Mancini, Grazia M.S.

    2009-01-01

    Cerebral palsy due to perinatal injury to cerebral white matter is usually not caused by genetic mutations, but by ischemia and/or inflammation. Here, we describe an autosomal-recessive type of tetraplegic cerebral palsy with mental retardation, reduction of cerebral white matter, and atrophy of the cerebellum in an inbred sibship. The phenotype was recorded and evolution followed for over 20 years. Brain lesions were studied by diffusion tensor MR tractography. Homozygosity mapping with SNPs was performed for identification of the chromosomal locus for the disease. In the 14 Mb candidate region on chromosome 7q22, RNA expression profiling was used for selecting among the 203 genes in the area. In postmortem brain tissue available from one patient, histology and immunohistochemistry were performed. Disease course and imaging were mostly reminiscent of hypoxic-ischemic tetraplegic cerebral palsy, with neuroaxonal degeneration and white matter loss. In all five patients, a donor splice site pathogenic mutation in intron 14 of the AP4M1 gene (c.1137+1G→T), was identified. AP4M1, encoding for the μ subunit of the adaptor protein complex-4, is involved in intracellular trafficking of glutamate receptors. Aberrant GluRδ2 glutamate receptor localization and dendritic spine morphology were observed in the postmortem brain specimen. This disease entity, which we refer to as congenital spastic tetraplegia (CST), is therefore a genetic model for congenital cerebral palsy with evidence for neuroaxonal damage and glutamate receptor abnormality, mimicking perinatally acquired hypoxic-ischemic white matter injury. PMID:19559397

  20. Particle acceleration in flares

    NASA Technical Reports Server (NTRS)

    Benz, Arnold O.; Kosugi, Takeo; Aschwanden, Markus J.; Benka, Steve G.; Chupp, Edward L.; Enome, Shinzo; Garcia, Howard; Holman, Gordon D.; Kurt, Victoria G.; Sakao, Taro

    1994-01-01

    Particle acceleration is intrinsic to the primary energy release in the impulsive phase of solar flares, and we cannot understand flares without understanding acceleration. New observations in soft and hard X-rays, gamma-rays and coherent radio emissions are presented, suggesting flare fragmentation in time and space. X-ray and radio measurements exhibit at least five different time scales in flares. In addition, some new observations of delayed acceleration signatures are also presented. The theory of acceleration by parallel electric fields is used to model the spectral shape and evolution of hard X-rays. The possibility of the appearance of double layers is further investigated.

  1. Charged particle accelerator grating

    DOEpatents

    Palmer, Robert B.

    1986-01-01

    A readily disposable and replaceable accelerator grating for a relativistic particle accelerator. The grating is formed for a plurality of liquid droplets that are directed in precisely positioned jet streams to periodically dispose rows of droplets along the borders of a predetermined particle beam path. A plurality of lasers are used to direct laser beams into the droplets, at predetermined angles, thereby to excite the droplets to support electromagnetic accelerating resonances on their surfaces. Those resonances operate to accelerate and focus particles moving along the beam path. As the droplets are distorted or destroyed by the incoming radiation, they are replaced at a predetermined frequency by other droplets supplied through the jet streams.

  2. Charged particle accelerator grating

    DOEpatents

    Palmer, Robert B.

    1986-09-02

    A readily disposable and replaceable accelerator grating for a relativistic particle accelerator. The grating is formed for a plurality of liquid droplets that are directed in precisely positioned jet streams to periodically dispose rows of droplets along the borders of a predetermined particle beam path. A plurality of lasers are used to direct laser beams into the droplets, at predetermined angles, thereby to excite the droplets to support electromagnetic accelerating resonances on their surfaces. Those resonances operate to accelerate and focus particles moving along the beam path. As the droplets are distorted or destroyed by the incoming radiation, they are replaced at a predetermined frequency by other droplets supplied through the jet streams.

  3. Accelerator-based BNCT.

    PubMed

    Kreiner, A J; Baldo, M; Bergueiro, J R; Cartelli, D; Castell, W; Thatar Vento, V; Gomez Asoia, J; Mercuri, D; Padulo, J; Suarez Sandin, J C; Erhardt, J; Kesque, J M; Valda, A A; Debray, M E; Somacal, H R; Igarzabal, M; Minsky, D M; Herrera, M S; Capoulat, M E; Gonzalez, S J; del Grosso, M F; Gagetti, L; Suarez Anzorena, M; Gun, M; Carranza, O

    2014-06-01

    The activity in accelerator development for accelerator-based BNCT (AB-BNCT) both worldwide and in Argentina is described. Projects in Russia, UK, Italy, Japan, Israel, and Argentina to develop AB-BNCT around different types of accelerators are briefly presented. In particular, the present status and recent progress of the Argentine project will be reviewed. The topics will cover: intense ion sources, accelerator tubes, transport of intense beams, beam diagnostics, the (9)Be(d,n) reaction as a possible neutron source, Beam Shaping Assemblies (BSA), a treatment room, and treatment planning in realistic cases.

  4. High Gradient Accelerator Research

    SciTech Connect

    Temkin, Richard

    2016-07-12

    The goal of the MIT program of research on high gradient acceleration is the development of advanced acceleration concepts that lead to a practical and affordable next generation linear collider at the TeV energy level. Other applications, which are more near-term, include accelerators for materials processing; medicine; defense; mining; security; and inspection. The specific goals of the MIT program are: • Pioneering theoretical research on advanced structures for high gradient acceleration, including photonic structures and metamaterial structures; evaluation of the wakefields in these advanced structures • Experimental research to demonstrate the properties of advanced structures both in low-power microwave cold test and high-power, high-gradient test at megawatt power levels • Experimental research on microwave breakdown at high gradient including studies of breakdown phenomena induced by RF electric fields and RF magnetic fields; development of new diagnostics of the breakdown process • Theoretical research on the physics and engineering features of RF vacuum breakdown • Maintaining and improving the Haimson / MIT 17 GHz accelerator, the highest frequency operational accelerator in the world, a unique facility for accelerator research • Providing the Haimson / MIT 17 GHz accelerator facility as a facility for outside users • Active participation in the US DOE program of High Gradient Collaboration, including joint work with SLAC and with Los Alamos National Laboratory; participation of MIT students in research at the national laboratories • Training the next generation of Ph. D. students in the field of accelerator physics.

  5. FFAGS for rapid acceleration

    SciTech Connect

    Carol J. Johnstone and Shane Koscielniak

    2002-09-30

    When large transverse and longitudinal emittances are to be transported through a circular machine, extremely rapid acceleration holds the advantage that the beam becomes immune to nonlinear resonances because there is insufficient time for amplitudes to build up. Uncooled muon beams exhibit large emittances and require fast acceleration to avoid decay losses and would benefit from this style of acceleration. The approach here employs a fixed-field alternating gradient or FFAG magnet structure and a fixed frequency acceleration system. Acceptance is enhanced by the use only of linear lattice elements, and fixed-frequency rf enables the use of cavities with large shunt resistance and quality factor.

  6. Acceleration of polarized protons in circular accelerators

    SciTech Connect

    Courant, E.D.; Ruth, R.D.

    1980-09-12

    The theory of depolarization in circular accelerators is presented. The spin equation is first expressed in terms of the particle orbit and then converted to the equivalent spinor equation. The spinor equation is then solved for three different situations: (1) a beam on a flat top near a resonance, (2) uniform acceleration through an isolated resonance, and (3) a model of a fast resonance jump. Finally, the depolarization coefficient, epsilon, is calculated in terms of properties of the particle orbit and the results are applied to a calculation of depolarization in the AGS.

  7. Cerebral small vessel disease and incident parkinsonism

    PubMed Central

    van der Holst, Helena M.; van Uden, Inge W.M.; Tuladhar, Anil M.; de Laat, Karlijn F.; van Norden, Anouk G.W.; Norris, David G.; van Dijk, Ewoud J.; Esselink, Rianne A.J.; Platel, Bram

    2015-01-01

    Objective: To investigate the relation between baseline cerebral small vessel disease (SVD) and the risk of incident parkinsonism using different MRI and diffusion tensor imaging (DTI) measures. Methods: In the Radboud University Nijmegen Diffusion Tensor and Magnetic Resonance Cohort (RUN DMC) study, a prospective cohort study, 503 elderly participants with SVD and without parkinsonism were included in 2006. During follow-up (2011–2012), parkinsonism was diagnosed according to UK Brain Bank criteria. Cox regression analysis was used to investigate the association between baseline imaging measures and incident all-cause parkinsonism and vascular parkinsonism (VP). Tract-based spatial statistics analysis was used to identify differences in baseline DTI measures of white matter (WM) tracts between participants with VP and without parkinsonism. Results: Follow-up was available from 501 participants (mean age 65.6 years; mean follow-up duration 5.2 years). Parkinsonism developed in 20 participants; 15 were diagnosed with VP. The 5-year risk of (any) parkinsonism was increased for those with a high white matter hyperintensity (WMH) volume (hazard ratio [HR] 1.8 per SD increase, 95% confidence interval [CI] 1.3–2.4) and a high number of lacunes (HR 1.4 per number increase, 95% CI 1.1–1.8) at baseline. For VP, this risk was also increased by the presence of microbleeds (HR 5.7, 95% CI 1.9–16.8) and a low gray matter volume (HR 0.4 per SD increase, 95% CI 0.2–0.8). Lower fractional anisotropy values in bifrontal WM tracts involved in movement control were observed in participants with VP compared to participants without parkinsonism. Conclusions: SVD at baseline, especially a high WMH volume and a high number of lacunes, is associated with incident parkinsonism. Our findings favor a role of SVD in the etiology of parkinsonism. PMID:26446068

  8. Does functional MRI detect activation in white matter? A review of emerging evidence, issues, and future directions

    PubMed Central

    Gawryluk, Jodie R.; Mazerolle, Erin L.; D'Arcy, Ryan C. N.

    2014-01-01

    Functional magnetic resonance imaging (fMRI) is a non-invasive technique that allows for visualization of activated brain regions. Until recently, fMRI studies have focused on gray matter. There are two main reasons white matter fMRI remains controversial: (1) the blood oxygen level dependent (BOLD) fMRI signal depends on cerebral blood flow and volume, which are lower in white matter than gray matter and (2) fMRI signal has been associated with post-synaptic potentials (mainly localized in gray matter) as opposed to action potentials (the primary type of neural activity in white matter). Despite these observations, there is no direct evidence against measuring fMRI activation in white matter and reports of fMRI activation in white matter continue to increase. The questions underlying white matter fMRI activation are important. White matter fMRI activation has the potential to greatly expand the breadth of brain connectivity research, as well as improve the assessment and diagnosis of white matter and connectivity disorders. The current review provides an overview of the motivation to investigate white matter fMRI activation, as well as the published evidence of this phenomenon. We speculate on possible neurophysiologic bases of white matter fMRI signals, and discuss potential explanations for why reports of white matter fMRI activation are relatively scarce. We end with a discussion of future basic and clinical research directions in the study of white matter fMRI. PMID:25152709

  9. Asperger's syndrome with unusual cerebral pathology: Case report and literature review.

    PubMed

    Liu, Liqiong; Vo, Van; Ware, Marcus; Xiong, Zhenggang

    2012-05-01

    A case of Asperger's syndrome with unusual cerebral pathological changes is reported. A 22-year-old male had been having diagnostic Asperger's syndrome since the age of eight and had epilepsy during the past two years. Radiological studies revealed a focal intra-axial cortical and subcortical cerebral lesion with hyper-intensity and non-enhancing contrast in the left frontal lobe. Histological and immunohistochemical studies demonstrated that the lesion consisted of cortical laminar disorganization, neuronal dysmorphism and increased heterotopic neurons in sub-cortical white matter. To our knowledge, this is the first case of Asperger's syndrome with focal cerebral pathological abnormalities rather than mini-columnar changes and the gyrial malformation reported in the literature.

  10. Actualities on molecular pathogenesis and repairing processes of cerebral damage in perinatal hypoxic-ischemic encephalopathy.

    PubMed

    Distefano, Giuseppe; Praticò, Andrea D

    2010-09-16

    Hypoxic-ischemic encephalopathy (HIE) is the most important cause of cerebral damage and long-term neurological sequelae in the perinatal period both in term and preterm infant. Hypoxic-ischemic (H-I) injuries develop in two phases: the ischemic phase, dominated by necrotic processes, and the reperfusion phase, dominated by apoptotic processes extending beyond ischemic areas. Due to selective ischemic vulnerability, cerebral damage affects gray matter in term newborns and white matter in preterm newborns with the typical neuropathological aspects of laminar cortical necrosis in the former and periventricular leukomalacia in the latter. This article summarises the principal physiopathological and biochemical processes leading to necrosis and/or apoptosis of neuronal and glial cells and reports recent insights into some endogenous and exogenous cellular and molecular mechanisms aimed at repairing H-I cerebral damage.

  11. Actualities on molecular pathogenesis and repairing processes of cerebral damage in perinatal hypoxic-ischemic encephalopathy

    PubMed Central

    2010-01-01

    Hypoxic-ischemic encephalopathy (HIE) is the most important cause of cerebral damage and long-term neurological sequelae in the perinatal period both in term and preterm infant. Hypoxic-ischemic (H-I) injuries develop in two phases: the ischemic phase, dominated by necrotic processes, and the reperfusion phase, dominated by apoptotic processes extending beyond ischemic areas. Due to selective ischemic vulnerability, cerebral damage affects gray matter in term newborns and white matter in preterm newborns with the typical neuropathological aspects of laminar cortical necrosis in the former and periventricular leukomalacia in the latter. This article summarises the principal physiopathological and biochemical processes leading to necrosis and/or apoptosis of neuronal and glial cells and reports recent insights into some endogenous and exogenous cellular and molecular mechanisms aimed at repairing H-I cerebral damage. PMID:20846380

  12. White light emitting diodes

    NASA Astrophysics Data System (ADS)

    Baur, J.; Schlotter, P.; Schneider, J.

    Using blue-emitting GaN LEDs on SiC substrate chips as primary light sources, we have fabricated green, yellow, red and white light emitting diodes (LUCOLEDs). The generation of mixed colors, as turquoise and magenta, is also demonstrated. The underlying physical principle is that of luminescence downconversion (Stokes shift), as typical for organic dye molecules and many inorganic phosphors. For white light generation via the LUCOLED principle, the phosphor Y3Al5O12:Ce3+(4f1) is ideally suited. The optical characteristics of Ce3+(4f1) in Y3Al5O12(YAG) are discussed in detail. Possibilities to "tune" the white color by various substitutions in the garnet lattice are shortly outlined.

  13. White LED performance

    NASA Astrophysics Data System (ADS)

    Gu, Yimin; Narendran, Nadarajah; Freyssinier, Jean Paul

    2004-10-01

    Two life tests were conducted to compare the effects of drive current and ambient temperature on the degradation rate of 5 mm and high-flux white LEDs. Tests of 5 mm white LED arrays showed that junction temperature increases produced by drive current had a greater effect on the rate of light output degradation than junction temperature increases from ambient heat. A preliminary test of high-flux white LEDs showed the opposite effect, with junction temperature increases from ambient heat leading to a faster depreciation. However, a second life test is necessary to verify this finding. The dissimilarity in temperature effect among 5 mm and high-flux LEDs is likely caused by packaging differences between the two device types.

  14. Imaging characteristics of cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL)

    PubMed Central

    Stojanov, Dragan; Aracki-Trenkic, Aleksandra; Vojinovic, Slobodan; Ljubisavljevic, Srdjan; Benedeto-Stojanov, Daniela; Tasic, Aleksandar; Vujnovic, Sasa

    2015-01-01

    Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) is an autosomal dominant vascular disorder. Diagnosis and follow-up in patients with CADASIL are based mainly on magnetic resonance imaging (MRI). MRI shows white matter hyperintensities (WMHs), lacunar infarcts and cerebral microbleeds (CMBs). WMHs lesions tend to be symmetrical and bilateral, distributed in the periventricular and deep white matter. The anterior temporal lobe and external capsules are predilection sites for WMHs, with higher specificity and sensitivity of anterior temporal lobe involvement compared to an external capsule involvement. Lacunar infarcts are presented by an imaging signal that has intensity of cerebrospinal fluid in all MRI sequences. They are localized within the semioval center, thalamus, basal ganglia and pons. CMBs are depicted as focal areas of signal loss on T2 images which increases in size on the T2*-weighted gradient echo planar images (“blooming effect”). PMID:25725137

  15. Scaling FFAG accelerator for muon acceleration

    SciTech Connect

    Lagrange, JB.; Planche, T.; Mori, Y.

    2011-10-06

    Recent developments in scaling fixed field alternating gradient (FFAG) accelerators have opened new ways for lattice design, with straight sections, and insertions like dispersion suppressors. Such principles and matching issues are detailed in this paper. An application of these new concepts is presented to overcome problems in the PRISM project.

  16. Scaling FFAG accelerator for muon acceleration

    NASA Astrophysics Data System (ADS)

    Lagrange, JB.; Planche, T.; Mori, Y.

    2011-10-01

    Recent developments in scaling fixed field alternating gradient (FFAG) accelerators have opened new ways for lattice design, with straight sections, and insertions like dispersion suppressors. Such principles and matching issues are detailed in this paper. An application of these new concepts is presented to overcome problems in the PRISM project.

  17. Angular velocities, angular accelerations, and coriolis accelerations

    NASA Technical Reports Server (NTRS)

    Graybiel, A.

    1975-01-01

    Weightlessness, rotating environment, and mathematical analysis of Coriolis acceleration is described for man's biological effective force environments. Effects on the vestibular system are summarized, including the end organs, functional neurology, and input-output relations. Ground-based studies in preparation for space missions are examined, including functional tests, provocative tests, adaptive capacity tests, simulation studies, and antimotion sickness.

  18. Combustion of White Phosphorus

    NASA Astrophysics Data System (ADS)

    Keiter, Richard L.; Gamage, Chaminda P.

    2001-07-01

    The reaction of white phosphorus with pure oxygen is conveniently and safely demonstrated by carrying out the reaction in a retort that has its open end submerged in water. After filling the retort with oxygen gas, a small amount of white phosphorus is introduced and heated with a hot-plate until it ignites. The spectacular reaction leads to consumption and expulsion of oxygen gas, creation of a partial vacuum in the retort, and back suction of water that extinguishes the combustion. Featured on the Cover

  19. White light velocity interferometer

    DOEpatents

    Erskine, D.J.

    1999-06-08

    The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s. 41 figs.

  20. White light velocity interferometer

    DOEpatents

    Erskine, D.J.

    1997-06-24

    The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s. 41 figs.

  1. White light velocity interferometer

    DOEpatents

    Erskine, David J.

    1999-01-01

    The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s.

  2. White light velocity interferometer

    DOEpatents

    Erskine, David J.

    1997-01-01

    The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s.

  3. Intracranial intraaxial cerebral tufted angioma: case report.

    PubMed

    D'Amico, Randy S; Zanazzi, George; Hargus, Gunnar; Dyster, Timothy; Chan, Shirley; Lignelli-Dipple, Angela; Wang, Tony J C; Faust, Phyllis L; McKhann, Guy M

    2017-02-24

    Tufted angioma (TA) is a rare, slow-growing, vascular lesion that commonly presents as a solitary macule, papule, or nodule arising in the soft tissues of the torso, extremities, and head and neck in children and young adults. Adult-onset cases have been infrequently reported. While typically benign, TAs may be locally aggressive. Complete physical examination and hematological workup are recommended in patients with TA to exclude the presence of Kasabach-Merritt phenomenon (KMP). The authors describe the case of a 69-year-old man with a contrast-enhancing frontal lobe lesion, with surrounding vasogenic edema, which was treated by gross-total resection. Characteristic histological features of a TA were demonstrated, with multiple cannonball-like tufts of densely packed capillaries emanating from intraparenchymal vessels in cerebral cortex and adjacent white matter. Tumor recurrence was detected after 4 months and treated with adjuvant Gamma Knife radiosurgery. To the extent of the authors' knowledge, this case illustrates the first report of TA presenting in an adult as an intracranial intraaxial tumor without associated KMP. The fairly rapid regrowth of this tumor, requiring adjuvant treatment after resection, is consistent with a potential for locally aggressive growth in a TA occurring in the brain.

  4. Vascular permeability in cerebral cavernous malformations.

    PubMed

    Mikati, Abdul G; Khanna, Omaditya; Zhang, Lingjiao; Girard, Romuald; Shenkar, Robert; Guo, Xiaodong; Shah, Akash; Larsson, Henrik B W; Tan, Huan; Li, Luying; Wishnoff, Matthew S; Shi, Changbin; Christoforidis, Gregory A; Awad, Issam A

    2015-10-01

    Patients with the familial form of cerebral cavernous malformations (CCMs) are haploinsufficient for the CCM1, CCM2, or CCM3 gene. Loss of corresponding CCM proteins increases RhoA kinase-mediated endothelial permeability in vitro, and in mouse brains in vivo. A prospective case-controlled observational study investigated whether the brains of human subjects with familial CCM show vascular hyperpermeability by dynamic contrast-enhanced quantitative perfusion magnetic resonance imaging, in comparison with CCM cases without familial disease, and whether lesional or brain vascular permeability correlates with CCM disease activity. Permeability in white matter far (WMF) from lesions was significantly greater in familial than in sporadic cases, but was similar in CCM lesions. Permeability in WMF increased with age in sporadic patients, but not in familial cases. Patients with more aggressive familial CCM disease had greater WMF permeability compared to those with milder disease phenotype, but similar lesion permeability. Subjects receiving statin medications for routine cardiovascular indications had a trend of lower WMF, but not lesion, permeability. This is the first demonstration of brain vascular hyperpermeability in humans with an autosomal dominant disease, as predicted mechanistically. Brain permeability, more than lesion permeability, may serve as a biomarker of CCM disease activity, and help calibrate potential drug therapy.

  5. Vascular permeability in cerebral cavernous malformations

    PubMed Central

    Mikati, Abdul G; Khanna, Omaditya; Zhang, Lingjiao; Girard, Romuald; Shenkar, Robert; Guo, Xiaodong; Shah, Akash; Larsson, Henrik BW; Tan, Huan; Li, Luying; Wishnoff, Matthew S; Shi, Changbin; Christoforidis, Gregory A; Awad, Issam A

    2015-01-01

    Patients with the familial form of cerebral cavernous malformations (CCMs) are haploinsufficient for the CCM1, CCM2, or CCM3 gene. Loss of corresponding CCM proteins increases RhoA kinase-mediated endothelial permeability in vitro, and in mouse brains in vivo. A prospective case-controlled observational study investigated whether the brains of human subjects with familial CCM show vascular hyperpermeability by dynamic contrast-enhanced quantitative perfusion magnetic resonance imaging, in comparison with CCM cases without familial disease, and whether lesional or brain vascular permeability correlates with CCM disease activity. Permeability in white matter far (WMF) from lesions was significantly greater in familial than in sporadic cases, but was similar in CCM lesions. Permeability in WMF increased with age in sporadic patients, but not in familial cases. Patients with more aggressive familial CCM disease had greater WMF permeability compared to those with milder disease phenotype, but similar lesion permeability. Subjects receiving statin medications for routine cardiovascular indications had a trend of lower WMF, but not lesion, permeability. This is the first demonstration of brain vascular hyperpermeability in humans with an autosomal dominant disease, as predicted mechanistically. Brain permeability, more than lesion permeability, may serve as a biomarker of CCM disease activity, and help calibrate potential drug therapy. PMID:25966944

  6. Hypertension and Cerebral Hemorrhage: A Malpractice Controversy

    PubMed Central

    Franklin, Stanley S.; Hunt, Marshall T.; Vogt, Thomas; Walsh, Gregory; Paglia, Donald E.

    1980-01-01

    The plaintiff alleged that failure of the attending physician to manage her husband's hypertension properly resulted in his death from intracerebral hemorrhage. Four lines of evidence supported the defendant: (1) In 1970 to 1971 there was uncertainty in the medical community whether mild hypertension should be treated with drugs; this uncertainty still existed at the time of the trial. (2) Severe hypertension and advanced age are the two most important predisposing factors leading to intracerebral hemorrhage; the deceased patient had neither. (3) Hemorrhage into the cerebral cortex and underlying white matter is not typical of hypertensive intracerebral bleeding; more likely, rupture of an arteriovenous malformation occurred. (4) A diagnosis of hypertensive intracerebral hemorrhage is not one of exclusion but requires objective evidence of vascular change in the brain, heart and kidney; these changes were not found in the deceased patient. In conclusion, an expert witness should testify objectively rather than be the advocate of a lawyer's theory of liability. ImagesFig. 6.Fig. 7.Fig. 9.Fig. 10. PMID:7233893

  7. Induction linear accelerators

    NASA Astrophysics Data System (ADS)

    Birx, Daniel

    1992-03-01

    Among the family of particle accelerators, the Induction Linear Accelerator is the best suited for the acceleration of high current electron beams. Because the electromagnetic radiation used to accelerate the electron beam is not stored in the cavities but is supplied by transmission lines during the beam pulse it is possible to utilize very low Q (typically<10) structures and very large beam pipes. This combination increases the beam breakup limited maximum currents to of order kiloamperes. The micropulse lengths of these machines are measured in 10's of nanoseconds and duty factors as high as 10-4 have been achieved. Until recently the major problem with these machines has been associated with the pulse power drive. Beam currents of kiloamperes and accelerating potentials of megavolts require peak power drives of gigawatts since no energy is stored in the structure. The marriage of liner accelerator technology and nonlinear magnetic compressors has produced some unique capabilities. It now appears possible to produce electron beams with average currents measured in amperes, peak currents in kiloamperes and gradients exceeding 1 MeV/meter, with power efficiencies approaching 50%. The nonlinear magnetic compression technology has replaced the spark gap drivers used on earlier accelerators with state-of-the-art all-solid-state SCR commutated compression chains. The reliability of these machines is now approaching 1010 shot MTBF. In the following paper we will briefly review the historical development of induction linear accelerators and then discuss the design considerations.

  8. Accelerator Science: Why RF?

    SciTech Connect

    Lincoln, Don

    2016-12-21

    Particle accelerators can fire beams of subatomic particles at near the speed of light. The accelerating force is generated using radio frequency technology and a whole lot of interesting features. In this video, Fermilab’s Dr. Don Lincoln explains how it all works.

  9. Particle Acceleration in Jets

    NASA Technical Reports Server (NTRS)

    Nishikawa, Ken-Ichi

    2005-01-01

    Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., active galactic nuclei (AGNs), gamma ray burst (GRBs), and Galactic microquasar systems usually have power-law emission spectra. Fermi acceleration is the mechanism usually assumed for the acceleration of particles in astrophysical environments.

  10. Accelerators Beyond The Tevatron?

    SciTech Connect

    Lach, Joseph; /Fermilab

    2010-07-01

    Following the successful operation of the Fermilab superconducting accelerator three new higher energy accelerators were planned. They were the UNK in the Soviet Union, the LHC in Europe, and the SSC in the United States. All were expected to start producing physics about 1995. They did not. Why?

  11. Accelerators (3/5)

    ScienceCinema

    None

    2016-07-12

    1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges Prerequisite knowledge: Previous knowledge of accelerators is not required.

  12. Diagnostics for induction accelerators

    SciTech Connect

    Fessenden, T.J.

    1996-04-01

    The induction accelerator was conceived by N. C. Christofilos and first realized as the Astron accelerator that operated at LLNL from the early 1960`s to the end of 1975. This accelerator generated electron beams at energies near 6 MeV with typical currents of 600 Amperes in 400 ns pulses. The Advanced Test Accelerator (ATA) built at Livermore`s Site 300 produced 10,000 Ampere beams with pulse widths of 70 ns at energies approaching 50 MeV. Several other electron and ion induction accelerators have been fabricated at LLNL and LBNL. This paper reviews the principal diagnostics developed through efforts by scientists at both laboratories for measuring the current, position, energy, and emittance of beams generated by these high current, short pulse accelerators. Many of these diagnostics are closely related to those developed for other accelerators. However, the very fast and intense current pulses often require special diagnostic techniques and considerations. The physics and design of the more unique diagnostics developed for electron induction accelerators are presented and discussed in detail.

  13. Accelerators (4/5)

    ScienceCinema

    None

    2016-07-12

    1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges Prerequisite knowledge: Previous knowledge of accelerators is not required.

  14. Measuring Model Rocket Acceleration.

    ERIC Educational Resources Information Center

    Jenkins, Randy A.

    1993-01-01

    Presents an experiment that measures the acceleration and velocity of a model rocket. Lift-off information is transmitted to a computer that creates a graph of the velocity. Discusses the analysis of the computer-generated data and differences between calculated and experimental velocity and acceleration of several rocket types. (MDH)

  15. Microscale acceleration history discriminators

    DOEpatents

    Polosky, Marc A.; Plummer, David W.

    2002-01-01

    A new class of micromechanical acceleration history discriminators is claimed. These discriminators allow the precise differentiation of a wide range of acceleration-time histories, thereby allowing adaptive events to be triggered in response to the severity (or lack thereof) of an external environment. Such devices have applications in airbag activation, and other safety and surety applications.

  16. Accelerators (5/5)

    ScienceCinema

    None

    2016-07-12

    1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges Prerequisite knowledge: Previous knowledge of accelerators is not required.

  17. Accelerators Beyond The Tevatron?

    SciTech Connect

    Lach, Joseph

    2010-07-29

    Following the successful operation of the Fermilab superconducting accelerator three new higher energy accelerators were planned. They were the UNK in the Soviet Union, the LHC in Europe, and the SSC in the United States. All were expected to start producing physics about 1995. They did not. Why?.

  18. Increased arterial diameters in the posterior cerebral circulation in men with Fabry disease.

    PubMed

    Uçeyler, Nurcan; Homola, György A; Guerrero González, Hans; Kramer, Daniela; Wanner, Christoph; Weidemann, Frank; Solymosi, László; Sommer, Claudia

    2014-01-01

    A high load of white matter lesions and enlarged basilar arteries have been shown in selected patients with Fabry disease, a disorder associated with an increased stroke risk. We studied a large cohort of patients with Fabry disease to differentially investigate white matter lesion load and cerebral artery diameters. We retrospectively analyzed cranial magnetic resonance imaging scans of 87 consecutive Fabry patients, 20 patients with ischemic stroke, and 36 controls. We determined the white matter lesion load applying the Fazekas score on fluid-attenuated inversion recovery sequences and measured the diameters of cerebral arteries on 3D-reconstructions of the time-of-flight-MR-angiography scans. Data of different Fabry patient subgroups (males-females; normal-impaired renal function) were compared with data of patients with stroke and controls. A history of stroke or transient ischemic attacks was present in 4/30 males (13%) and 5/57 (9%) females with Fabry disease, all in the anterior circulation. Only one man with Fabry disease showed confluent cerebral white matter lesions in the Fazekas score assessment (1%). Male Fabry patients had a larger basilar artery (p<0.01) and posterior cerebral artery diameter (p<0.05) compared to male controls. This was independent of disease severity as measured by renal function and did not lead to changes in arterial blood flow properties. A basilar artery diameter of >3.2 mm distinguished between men with Fabry disease and controls (sensitivity: 87%, specificity: 86%, p<0.001), but not from stroke patients. Enlarged arterial diameters of the posterior circulation are present only in men with Fabry disease independent of disease severity.

  19. Accelerators, Beams And Physical Review Special Topics - Accelerators And Beams

    SciTech Connect

    Siemann, R.H.; /SLAC

    2011-10-24

    Accelerator science and technology have evolved as accelerators became larger and important to a broad range of science. Physical Review Special Topics - Accelerators and Beams was established to serve the accelerator community as a timely, widely circulated, international journal covering the full breadth of accelerators and beams. The history of the journal and the innovations associated with it are reviewed.

  20. Neuroevolutional Approach to Cerebral Palsy and Speech.

    ERIC Educational Resources Information Center

    Mysak, Edward D.

    Intended for cerebral palsy specialists, the book emphasizes the contribution that a neuroevolutional approach to therapy can make to habilitation goals of the child with cerebral palsy and applies the basic principles of the Bobath approach to therapy. The first section discusses cerebral palsy as a reflection of disturbed neuro-ontogenisis and…

  1. Cerebral vasculitis associated with cocaine abuse

    SciTech Connect

    Kaye, B.R.; Fainstat, M.

    1987-10-16

    A case of cerebral vasculitis in a previously healthy 22-year-old man with a history of cocaine abuse is described. Cerebral angiograms showed evidence of vasculitis. A search for possible causes other than cocaine produced no results. The authors include cocaine with methamphetamines, heroin, and ephedrine as illicit drugs that can cause cerebral vasculitis.

  2. Behaviour Problems Amongst Children With Cerebral Palsy.

    ERIC Educational Resources Information Center

    Oswin, Maureen

    Based on 6 years of work with cerebral palsied children, the thesis considers types and causes of cerebral palsy, the life pattern of the child with cerebral palsy from early years to adolescence, and the effect of the handicapped child on his parents and family. Literature on behavior disorders is reviewed, and kinds of behavior problems are…

  3. Effects of hyperglycemia and effects of ketosis on cerebral perfusion, cerebral water distribution, and cerebral metabolism.

    PubMed

    Glaser, Nicole; Ngo, Catherine; Anderson, Steven; Yuen, Natalie; Trifu, Alexandra; O'Donnell, Martha

    2012-07-01

    Diabetic ketoacidosis (DKA) may cause brain injuries in children. The mechanisms responsible are difficult to elucidate because DKA involves multiple metabolic derangements. We aimed to determine the independent effects of hyperglycemia and ketosis on cerebral metabolism, blood flow, and water distribution. We used magnetic resonance spectroscopy to measure ratios of cerebral metabolites (ATP to inorganic phosphate [Pi], phosphocreatine [PCr] to Pi, N-acetyl aspartate [NAA] to creatine [Cr], and lactate to Cr) and diffusion-weighted imaging and perfusion-weighted imaging to assess cerebral water distribution (apparent diffusion coefficient [ADC] values) and cerebral blood flow (CBF) in three groups of juvenile rats (hyperglycemic, ketotic, and normal control). ATP-to-Pi ratio was reduced in both hyperglycemic and ketotic rats in comparison with controls. PCr-to-Pi ratio was reduced in the ketotic group, and there was a trend toward reduction in the hyperglycemic group. No significant differences were observed in NAA-to-Cr or lactate-to-Cr ratio. Cortical ADC was reduced in both groups (indicating brain cell swelling). Cortical CBF was also reduced in both groups. We conclude that both hyperglycemia and ketosis independently cause reductions in cerebral high-energy phosphates, CBF, and cortical ADC values. These effects may play a role in the pathophysiology of DKA-related brain injury.

  4. Cerebral Palsy: A Dental Update

    PubMed Central

    Sehrawat, Nidhi; Bansal, Kalpana; Chopra, Radhika

    2014-01-01

    ABSTRACT Special and medically compromised patients present a unique population that challenges the dentist’s skill and knowledge. Providing oral care to people with cerebral palsy (CP) requires adaptation of the skills we use everyday. In fact, most people with mild or moderate forms of CP can be treated successfully in the general practice setting. This article is to review various dental considerations and management of a CP patient. How to cite this article: Sehrawat N, Marwaha M, Bansal K, Chopra R. Cerebral Palsy: A Dental Update. Int J Clin Pediatr Dent 2014;7(2):109-118. PMID:25356010

  5. White Sea - Russia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    At bottom center of this true-color Moderate Resolution Imaging Spectroradiometer (MODIS) image from April 13, 2001, the White Sea in western Russia is becoming free of ice in its southern extent. Meanwhile, the blue-green waters along the coast of the peninsula jutting out into the Barents Sea to the northeast could be due to a phytoplankton bloom.

  6. Liquid White Enamel.

    ERIC Educational Resources Information Center

    Widmar, Marge

    1985-01-01

    A secondary teacher describes how she has her students use liquid white enamel. With the enameling process, students can create lasting, exciting artwork. They can exercise an understanding of design and color while learning the value of careful, sustained craft skills. (RM)

  7. White Star technology.

    PubMed

    Olson, Randall J; Kumar, Rajiv

    2003-02-01

    White Star micropulse technology is a software modification that allows extremely short bursts of ultrasound energy. Studies have shown that this decreases wound heat build-up with the retained efficiency of continuous ultrasound. Decreased energy utilization with improved corneal function and improved nuclear fragment followability appear to be additional benefits.

  8. Snow White 5 Trench

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This image was acquired by NASA's Phoenix Mars Lander's Robotic Arm Camera on the 35th Martian day of the mission, or Sol 34 (June 29, 2008), after the May 25, 2008, landing. This image shows the trench informally called 'Snow White 5.' The trench is 4-to-5 centimeters (about 1.5-to-1.9 inches) deep, 24 centimeters (about 9 inches) wide and 33 centimeters (13 inches) long.

    Snow White 5 is Phoenix's current active digging area after additional trenching, grooming, and scraping by Phoenix's Robotic Arm in the last few sols to trenches informally called Snow White 1, 2, 3, and 4. Near the top center of the image is the Robotic Arm's Thermal and Electrical Conductivity Probe.

    Snow White 5 is located in a patch of Martian soil near the center of a polygonal surface feature, nicknamed 'Cheshire Cat.' The digging site has been named 'Wonderland.'

    This image has been enhanced to brighten shaded areas.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  9. Black and White Slides.

    ERIC Educational Resources Information Center

    Tanner, Jackie

    1979-01-01

    Outlines procedures for using some photographic techniques to start a black and white slide collection. Instructions are given for: (1) necessary equipment and materials; (2) photographing images such as photos, charts or drawings; (3) developing the film; and (4) setting up the filing system. Photographs and drawings illustrate the process. (AMH)

  10. The White Sea, Russia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Editor's Note: The caption below, published on May 10, 2001, is incorrect. According to Masha Vorontsova, director of the International Fund for Animal Welfare in Moscow, the situation with the seal pups in the White Sea is normal. There is no disaster and there never was. For more details, refer to the article entitled 'No Danger' on the New Scientist home page. The Earth Observatory regrets the earlier errant report. Original Caption According to the Russian Polar Research Institute for Fisheries and Oceanography, between 250,000 and 300,000 Greenland seal pups face death by starvation over the next two months due to a cruel trick by mother nature. The seals, most of them less than two months old, are trapped on ice sheets that remain locked in the White Sea, located near Archangel in Northern Russia. Typically, during the spring thaw the ice sheets break up and flow with the currents northward into the Barents Sea, the seals' spring feeding grounds. The seal pups hitch a ride on the ice floes, living on their own individual stores of fat until they arrive in the Barents Sea. Their mothers departed for the Barents Sea weeks ago. In a normal year, the seal pups' trip from the White Sea out to the Barents takes about six weeks and the seals have adapted to rely upon this mechanism of mother nature. During their yearly migration, the mother seals usually stay with their pups and feed them until their pelts turn from white to grey--a sign that the pups are mature enough to swim and feed themselves. Unfortunately, this year unusually strong northerly winds created a bottleneck of ice near the mouth of the white sea, thus blocking the flow of ice and trapping the pups. These true-color images of the White Sea were acquired by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra spacecraft. This image, taken May 2, 2000 that there is usually much less ice in the White Sea this time of year as most of it is typically en route to the

  11. White Dwarf Stars

    NASA Astrophysics Data System (ADS)

    Kepler, S. O.

    2014-10-01

    White dwarfs are the evolutionary endpoint for nearly 95% of all stars born in our Galaxy, the final stages of evolution of all low- and intermediate mass stars, i.e., main sequence stars with masses below (8.5± 1.5) M_{odot}, depending on metallicity of the progenitor, mass loss and core overshoot. Massive white dwarfs are intrinsically rare objects, tand produce a gap in the determination of the initial vs. final mass relation at the high mass end (e.g. Weidemann 2000 A&A, 363, 647; Kalirai et al. 2008, ApJ, 676, 594; Williams, Bolte & Koester 2009, ApJ, 693, 355). Main sequences stars with higher masses will explode as SNII (Smartt S. 2009 ARA&A, 47, 63), but the limit does depend on the metallicity of the progenitor. Massive white dwarfs are probably SNIa progenitors through accretion or merger. They are rare, being the final product of massive stars (less common) and have smaller radius (less luminous). Kepler et al. 2007 (MNRAS, 375, 1315), Kleinman et al. 2013 (ApJS, 204, 5) estimate only 1-2% white dwarfs have masses above 1 M_{odot}. The final stages of evolution after helium burning are a race between core growth and loss of the H-rich envelope in a stellar wind. When the burning shell is exposed, the star rapidly cools and burning ceases, leaving a white dwarf. As they cool down, the magnetic field freezes in, ranging from a few kilogauss to a gigagauss. Peculiar type Ia SN 2006gz, SN 2007if, SN 2009dc, SN 2003fg suggest progenitors in the range 2.4-2.8 M_{odot}, and Das U. & Mukhopadhyay B. (2012, Phys. Rev. D, 86, 042001) estimate that the Chandrasekhar limit increases to 2.3-2.6 M_{odot} for extremely high magnetic field stars, but differential rotation induced by accretion could also increase it, according to Hachisu I. et al. 2012 (ApJ, 744, 69). García-Berro et al. 2012, ApJ, 749, 25, for example, proposes double degenerate mergers are the progenitors of high-field magnetic white dwarfs. We propose magnetic fields enhance the line broadening in

  12. Visual evoked potentials and heart rate during white noise stimulation.

    PubMed

    Lucchese, F; Mecacci, L

    1999-03-01

    Visual evoked potentials (VEPs) were recorded in 12 adult participants as a function of the temporal frequency of a phase-reversed checkerboard, with or without a simultaneously presented white noise. During the VEP recordings also the pulse rate was measured. VEP amplitude changed as function of temporal frequency, but it was not affected by noise. Pulse rate was stable during the session without noise, but it increased during the white noise stimulation at high temporal frequencies. Heart acceleration might be associated to conditions when processing at low levels of visual sensitivity (high temporal frequencies) is furthermore disturbed by interfering stimulation (noise).

  13. What is white?

    PubMed Central

    Bosten, J. M.; Beer, R. D.; MacLeod, D. I. A.

    2015-01-01

    To shed light on the perceptual basis of the color white, we measured settings of unique white in a dark surround. We find that settings reliably show more variability in an oblique (blue-yellow) direction in color space than along the cardinal axes of the cone-opponent mechanisms. This is against the idea that white perception arises at the null point of the cone-opponent mechanisms, but one alternative possibility is that it occurs through calibration to the visual environment. We found that the locus of maximum variability in settings lies close to the locus of natural daylights, suggesting that variability may result from uncertainty about the color of the illuminant. We tested this by manipulating uncertainty. First, we altered the extent to which the task was absolute (requiring knowledge of the illumination) or relative. We found no clear effect of this factor on the reduction in sensitivity in the blue-yellow direction. Second, we provided a white surround as a cue to the illumination or left the surround dark. Sensitivity was selectively worse in the blue-yellow direction when the surround was black than when it was white. Our results can be functionally related to the statistics of natural images, where a greater blue-yellow dispersion is characteristic of both reflectances (where anisotropy is weak) and illuminants (where it is very pronounced). Mechanistically, the results could suggest a neural signal responsive to deviations from the blue-yellow locus or an adaptively matched range of contrast response functions for signals that encode different directions in color space. PMID:26641948

  14. Exploring Whiteness: A Study of Self Labels for White Americans.

    ERIC Educational Resources Information Center

    Martin, Judith N.; Krizek, Robert L.; Nakayama, Thomas K.; Bradford, Lisa

    1996-01-01

    Examines the preferences and meanings of labels for White Americans as discursively defined expressions of identity, after preliminary revelations of resistance by Whites to self-labeling was seen. Surveys 371 White undergraduate students, rating seven labels regarding preference and discussing feelings about self-labeling. Reveals that the most…

  15. Complicating Whiteness: Identifications of Veteran White Teachers in Multicultural Settings

    ERIC Educational Resources Information Center

    Miele, Anthony

    2013-01-01

    A scrupulous search of whiteness literatures in relation to multicultural education reveals a preponderance of scholarship noting White privilege and race evasiveness. Given contrasting scholarship arguing White identity as complicated, multifarious, and bound to social and historical context, concurrent with a dearth of scholarship that examines…

  16. Large electrostatic accelerators

    SciTech Connect

    Jones, C.M.

    1984-01-01

    The increasing importance of energetic heavy ion beams in the study of atomic physics, nuclear physics, and materials science has partially or wholly motivated the construction of a new generation of large electrostatic accelerators designed to operate at terminal potentials of 20 MV or above. In this paper, the author briefly discusses the status of these new accelerators and also discusses several recent technological advances which may be expected to further improve their performance. The paper is divided into four parts: (1) a discussion of the motivation for the construction of large electrostatic accelerators, (2) a description and discussion of several large electrostatic accelerators which have been recently completed or are under construction, (3) a description of several recent innovations which may be expected to improve the performance of large electrostatic accelerators in the future, and (4) a description of an innovative new large electrostatic accelerator whose construction is scheduled to begin next year. Due to time and space constraints, discussion is restricted to consideration of only tandem accelerators.

  17. White matter of the brain

    MedlinePlus

    White matter is found in the deeper tissues of the brain (subcortical). It contains nerve fibers (axons), which are ... or covering called myelin. Myelin gives the white matter its color. It also protects the nerve fibers ...

  18. Caffeine induced changes in cerebral circulation

    SciTech Connect

    Mathew, R.J.; Wilson, W.H.

    1985-09-01

    While the caffeine induced cerebral vasoconstriction is well documented, the effects of oral ingestion of the drug in a dose range comparable to the quantities in which it is usually consumed and the intensity and duration of the associated reduction in cerebral circulation are unknown. Cerebral blood flow was measured via the TTXenon inhalation technique before and thirty and ninety minutes after the oral administration of 250 mg of caffeine or a placebo, under double-blind conditions. Caffeine ingestion was found to be associated with significant reductions in cerebral perfusion thirty and ninety minutes later. The placebo group showed no differences between the three sets of cerebral blood flow values.

  19. The brain in myotonic dystrophy 1 and 2: evidence for a predominant white matter disease.

    PubMed

    Minnerop, Martina; Weber, Bernd; Schoene-Bake, Jan-Christoph; Roeske, Sandra; Mirbach, Sandra; Anspach, Christian; Schneider-Gold, Christiane; Betz, Regina C; Helmstaedter, Christoph; Tittgemeyer, Marc; Klockgether, Thomas; Kornblum, Cornelia

    2011-12-01

    Myotonic dystrophy types 1 and 2 are progressive multisystemic disorders with potential brain involvement. We compared 22 myotonic dystrophy type 1 and 22 myotonic dystrophy type 2 clinically and neuropsychologically well-characterized patients and a corresponding healthy control group using structural brain magnetic resonance imaging at 3 T (T(1)/T(2)/diffusion-weighted). Voxel-based morphometry and diffusion tensor imaging with tract-based spatial statistics were applied for voxel-wise analysis of cerebral grey and white matter affection (P(corrected) < 0.05). We further examined the association of structural brain changes with clinical and neuropsychological data. White matter lesions rated visually were more prevalent and severe in myotonic dystrophy type 1 compared with controls, with frontal white matter most prominently affected in both disorders, and temporal lesions restricted to myotonic dystrophy type 1. Voxel-based morphometry analyses demonstrated extensive white matter involvement in all cerebral lobes, brainstem and corpus callosum in myotonic dystrophy types 1 and 2, while grey matter decrease (cortical areas, thalamus, putamen) was restricted to myotonic dystrophy type 1. Accordingly, we found more prominent white matter affection in myotonic dystrophy type 1 than myotonic dystrophy type 2 by diffusion tensor imaging. Association fibres throughout the whole brain, limbic system fibre tracts, the callosal body and projection fibres (e.g. internal/external capsules) were affected in myotonic dystrophy types 1 and 2. Central motor pathways were exclusively impaired in myotonic dystrophy type 1. We found mild executive and attentional deficits in our patients when neuropsychological tests were corrected for manual motor dysfunctioning. Regression analyses revealed associations of white matter affection with several clinical parameters in both disease entities, but not with neuropsychological performance. We showed that depressed mood and fatigue were

  20. Vacuum Beat Wave Accelerator

    NASA Astrophysics Data System (ADS)

    Moore, C. I.; Hafizi, B.; Ting, A.; Burris, H. R.; Sprangle, P.; Esarey, E.; Ganguly, A.; Hirshfield, J. L.

    1997-11-01

    The Vacuum Beat Wave Accelerator (VBWA) is a particle acceleration scheme which uses the non-linear ponderomotive beating of two different frequency laser beams to accelerate electrons. A proof-of-principle experiment to demonstrate the VBWA is underway at the Naval Research Laboratory (NRL). This experiment will use the beating of a 1054 nm and 527 nm laser pulse from the NRL T-cubed laser to generate the beat wave and a 4.5 MeV RF electron gun as the electron source. Simulation results and the experimental design will be presented. The suitability of using axicon or higher order Gaussian laser beams will also be discussed.

  1. Ion beam accelerator system

    NASA Technical Reports Server (NTRS)

    Aston, Graeme (Inventor)

    1984-01-01

    A system is described that combines geometrical and electrostatic focusing to provide high ion extraction efficiency and good focusing of an accelerated ion beam. The apparatus includes a pair of curved extraction grids (16, 18) with multiple pairs of aligned holes positioned to direct a group of beamlets (20) along converging paths. The extraction grids are closely spaced and maintained at a moderate potential to efficiently extract beamlets of ions and allow them to combine into a single beam (14). An accelerator electrode device (22) downstream from the extraction grids, is at a much lower potential than the grids to accelerate the combined beam.

  2. Ion beam accelerator system

    NASA Technical Reports Server (NTRS)

    Aston, G. (Inventor)

    1981-01-01

    A system is described that combines geometrical and electrostatic focusing to provide high ion extraction efficiency and good focusing of an accelerated ion beam. The apparatus includes a pair of curved extraction grids with multiple pairs of aligned holes positioned to direct a group of beamlets along converging paths. The extraction grids are closely spaced and maintained at a moderate potential to efficiently extract beamlets of ions and allow them to combine into a single beam. An accelerator electrode device downstream from the extraction grids is at a much lower potential than the grids to accelerate the combined beam. The application of the system to ion implantation is mentioned.

  3. What are the Best Animal Models for Testing Early Intervention in Cerebral Palsy?

    PubMed Central

    Clowry, Gavin John; Basuodan, Reem; Chan, Felix

    2014-01-01

    Interventions to treat cerebral palsy should be initiated as soon as possible in order to restore the nervous system to the correct developmental trajectory. One drawback to this approach is that interventions have to undergo exceptionally rigorous assessment for both safety and efficacy prior to use in infants. Part of this process should involve research using animals but how good are our animal models? Part of the problem is that cerebral palsy is an umbrella term that covers a number of conditions. There are also many causal pathways to cerebral palsy, such as periventricular white matter injury in premature babies, perinatal infarcts of the middle cerebral artery, or generalized anoxia at the time of birth, indeed multiple causes, including intra-uterine infection or a genetic predisposition to infarction, may need to interact to produce a clinically significant injury. In this review, we consider which animal models best reproduce certain aspects of the condition, and the extent to which the multifactorial nature of cerebral palsy has been modeled. The degree to which the corticospinal system of various animal models human corticospinal system function and development is also explored. Where attempts have already been made to test early intervention in animal models, the outcomes are evaluated in light of the suitability of the model. PMID:25538677

  4. Cerebral ventricular volume during hyponatraemia.

    PubMed Central

    Decaux, G; Szyper, M; Grivegnée, A

    1983-01-01

    In order to determine if the neurologic manifestations in chronic hyponatraemia result partly from brain oedema, we measured the cerebral ventricular volume before and after correction of hyponatraemia in eight patients with central nervous system manifestations. Only the three patients with seizures showed a clear change in the ventricular size and probably had brain oedema. PMID:6101182

  5. Investigating cerebral oedema using poroelasticity.

    PubMed

    Vardakis, John C; Chou, Dean; Tully, Brett J; Hung, Chang C; Lee, Tsong H; Tsui, Po-Hsiang; Ventikos, Yiannis

    2016-01-01

    Cerebral oedema can be classified as the tangible swelling produced by expansion of the interstitial fluid volume. Hydrocephalus can be succinctly described as the abnormal accumulation of cerebrospinal fluid (CSF) within the brain which ultimately leads to oedema within specific sites of parenchymal tissue. Using hydrocephalus as a test bed, one is able to account for the necessary mechanisms involved in the interaction between oedema formation and cerebral fluid production, transport and drainage. The current state of knowledge about integrative cerebral dynamics and transport phenomena indicates that poroelastic theory may provide a suitable framework to better understand various diseases. In this work, Multiple-Network Poroelastic Theory (MPET) is used to develop a novel spatio-temporal model of fluid regulation and tissue displacement within the various scales of the cerebral environment. The model is applied through two formats, a one-dimensional finite difference - Computational Fluid Dynamics (CFD) coupling framework, as well as a two-dimensional Finite Element Method (FEM) formulation. These are used to investigate the role of endoscopic fourth ventriculostomy in alleviating oedema formation due to fourth ventricle outlet obstruction (1D coupled model) in addition to observing the capability of the FEM template in capturing important characteristics allied to oedema formation, like for instance in the periventricular region (2D model).

  6. Graft selection in cerebral revascularization.

    PubMed

    Baaj, Ali A; Agazzi, Siviero; van Loveren, Harry

    2009-05-01

    Cerebral revascularization constitutes an important treatment modality in the management of complex aneurysms, carotid occlusion, tumor, and moyamoya disease. Graft selection is a critical step in the planning of revascularization surgery, and depends on an understanding of graft and regional hemodynamics, accessibility, and patency rates. The goal of this review is to highlight some of these properties.

  7. Neuropathology of Acquired Cerebral Trauma.

    ERIC Educational Resources Information Center

    Bigler, Erin D.

    1987-01-01

    To help educators understand the cognitive and behavioral sequelae of cerebral injury, the neuropathology of traumatic brain injury and the main neuropathological features resulting from trauma-related brain damage are reviewed. A glossary with definitions of 37 neurological terms is appended. (Author/DB)

  8. Anxiety and Lateral Cerebral Function

    ERIC Educational Resources Information Center

    Tucker, Don M.; And Others

    1978-01-01

    Examines the effect of stressful and nonstressful experimental situations upon the processing capacity of each cerebral hemisphere, through observing the differential performance tasks presented to right and left visual half-fields (VHFs). Also examines attentional bias and lateral eye movements. (Author/RK)

  9. Sirt1 in cerebral ischemia

    PubMed Central

    Koronowski, Kevin B.; Perez-Pinzon, Miguel A.

    2015-01-01

    Cerebral ischemia is among the leading causes of death worldwide. It is characterized by a lack of blood flow to the brain that results in cell death and damage, ultimately causing motor, sensory, and cognitive impairments. Today, clinical treatment of cerebral ischemia, mostly stroke and cardiac arrest, is limited and new neuroprotective therapies are desperately needed. The Sirtuin family of oxidized nicotinamide adenine dinucleotide (NAD+)-dependent deacylases has been shown to govern several processes within the central nervous system as well as to possess neuroprotective properties in a variety of pathological conditions such as Alzheimer’s Disease, Parkinson’s Disease, and Huntington’s Disease, among others. Recently, Sirt1 in particular has been identified as a mediator of cerebral ischemia, with potential as a possible therapeutic target. To gather studies relevant to this topic, we used PubMed and previous reviews to locate, select, and resynthesize the lines of evidence presented here. In this review, we will first describe some functions of Sirt1 in the brain, mainly neurodevelopment, learning and memory, and metabolic regulation. Second, we will discuss the experimental evidence that has implicated Sirt1 as a key protein in the regulation of cerebral ischemia as well as a potential target for the induction of ischemic tolerance. PMID:26819971

  10. Confusional state and cerebral infarcts.

    PubMed Central

    García-Albea, E.

    1989-01-01

    Thirteen patients with confusional state and cerebral infarction were studied. Seven patients had optic pathway alterations. On computed tomographic scan, 2 patients had multiple infarctions and 10 had single infarctions, predominantly located in the temporo-occipital associative cortex. One patient had a normal scan. Reduction of 'selective attention', 'release' hallucinations, amnesic syndrome and secondary individual adjustment could explain the confusional state. PMID:2608563

  11. Cerebral gigantism with West syndrome.

    PubMed

    Ray, Munni; Malhi, P; Bhalla, A K; Singhi, P D

    2003-07-01

    A case of cerebral gigantism (Sotos syndrome) with West syndrome in a one-year-old male child is reported. The case had a large stature, typical facies and neurodevelopmental delay along with infantile spasms, which were refractory to treatment with valproate and clonazepam.

  12. Asteroseismology of White Dwarf Stars

    NASA Technical Reports Server (NTRS)

    Hansen, Carl J.

    1997-01-01

    The primary purpose of this investigation has been to study various aspects of multimode pulsations in variable white dwarfs. In particular, nonlinear interactions among pulsation modes in white dwarfs (and, to some extent, in other variable stars), analysis of recent observations where such interactions are important, and preliminary work on the effects of crystallization in cool white dwarfs are reported.

  13. Black Students in White Skins

    ERIC Educational Resources Information Center

    Snell, Joel C.

    2008-01-01

    Of the 281 million Americans, "Scientific American" estimates that White Africans (21% of White Caucasians) have Black heritage. This article discusses the present state of black elite and the transformation of black students in the United States. Some strategies to become a "white" student are also discussed.

  14. Egg White Phantoms for HIFU

    SciTech Connect

    Divkovic, Gabriela; Jenne, Juergen W.

    2005-03-28

    We used fresh egg white and polyacrylamide to create a transparent tissue mimicking phantom. Heating of phantoms by HIFU leads to egg white protein denaturation and creation of visible white lesions. We measured the acoustical and thermal properties and investigated the possibility to use such phantoms to study the lesion formation during the HIFU therapy.

  15. White Students' Understanding of Race: An Exploration of How White University Students, Raised in a Predominately White State, Experience Whiteness

    ERIC Educational Resources Information Center

    Smith, Barbara A.

    2014-01-01

    This study examines White university students' understanding of race. Based in the scholarship on higher education and diversity, and framed in Critical Race Theory (CRT), this study explores the racial awareness of White students. This study contributes to the literature on the racial experience of Whites and an understanding of how White…

  16. Intravascular Perfusion of Carbon Black Ink Allows Reliable Visualization of Cerebral Vessels

    PubMed Central

    Hasan, Mohammad R.; Herz, Josephine; Hermann, Dirk M.; Doeppner, Thorsten R.

    2013-01-01

    The anatomical structure of cerebral vessels is a key determinant for brain hemodynamics as well as the severity of injury following ischemic insults. The cerebral vasculature dynamically responds to various pathophysiological states and it exhibits considerable differences between strains and under conditions of genetic manipulations. Essentially, a reliable technique for intracranial vessel staining is essential in order to study the pathogenesis of ischemic stroke. Until recently, a set of different techniques has been employed to visualize the cerebral vasculature including injection of low viscosity resin, araldite F, gelatin mixed with various dyes1 (i.e. carmine red, India ink) or latex with2 or without3 carbon black. Perfusion of white latex compound through the ascending aorta has been first reported by Coyle and Jokelainen3. Maeda et al.2 have modified the protocol by adding carbon black ink to the latex compound for improved contrast visualization of the vessels after saline perfusion of the brain. However, inefficient perfusion and inadequate filling of the vessels are frequently experienced due to high viscosity of the latex compound4. Therefore, we have described a simple and cost-effective technique using a mixture of two commercially available carbon black inks (CB1 and CB2) to visualize the cerebral vasculature in a reproducible manner5. We have shown that perfusion with CB1+CB2 in mice results in staining of significantly smaller cerebral vessels at a higher density in comparison to latex perfusion5. Here, we describe our protocol to identify the anastomotic points between the anterior (ACA) and middle cerebral arteries (MCA) to study vessel variations in mice with different genetic backgrounds. Finally, we demonstrate the feasibility of our technique in a transient focal cerebral ischemia model in mice by combining CB1+CB2-mediated vessel staining with TTC staining in various degrees of ischemic injuries. PMID:23328838

  17. Intravascular perfusion of carbon black ink allows reliable visualization of cerebral vessels.

    PubMed

    Hasan, Mohammad R; Herz, Josephine; Hermann, Dirk M; Doeppner, Thorsten R

    2013-01-04

    The anatomical structure of cerebral vessels is a key determinant for brain hemodynamics as well as the severity of injury following ischemic insults. The cerebral vasculature dynamically responds to various pathophysiological states and it exhibits considerable differences between strains and under conditions of genetic manipulations. Essentially, a reliable technique for intracranial vessel staining is essential in order to study the pathogenesis of ischemic stroke. Until recently, a set of different techniques has been employed to visualize the cerebral vasculature including injection of low viscosity resin, araldite F, gelatin mixed with various dyes (i.e. carmine red, India ink) or latex with or without carbon black. Perfusion of white latex compound through the ascending aorta has been first reported by Coyle and Jokelainen. Maeda et al. have modified the protocol by adding carbon black ink to the latex compound for improved contrast visualization of the vessels after saline perfusion of the brain. However, inefficient perfusion and inadequate filling of the vessels are frequently experienced due to high viscosity of the latex compound. Therefore, we have described a simple and cost-effective technique using a mixture of two commercially available carbon black inks (CB1 and CB2) to visualize the cerebral vasculature in a reproducible manner. We have shown that perfusion with CB1+CB2 in mice results in staining of significantly smaller cerebral vessels at a higher density in comparison to latex perfusion. Here, we describe our protocol to identify the anastomotic points between the anterior (ACA) and middle cerebral arteries (MCA) to study vessel variations in mice with different genetic backgrounds. Finally, we demonstrate the feasibility of our technique in a transient focal cerebral ischemia model in mice by combining CB1+CB2-mediated vessel staining with TTC staining in various degrees of ischemic injuries.

  18. Subjective cognitive failures in patients with hypertension are related to cognitive performance and cerebral microbleeds.

    PubMed

    Uiterwijk, Renske; Huijts, Marjolein; Staals, Julie; Duits, Annelien; Gronenschild, Ed; Kroon, Abraham A; de Leeuw, Peter W; van Oostenbrugge, Robert J

    2014-09-01

    Previous studies on the relationship between subjective cognitive failures (SCF) and objective cognitive function have shown inconsistent results. In addition, research on the association between SCF and imaging markers of cerebral small vessel disease is limited. We investigated whether SCF in patients with essential hypertension, who are at high risk of cerebral small vessel disease, are associated with objective cognitive function and magnetic resonance imaging manifestations of cerebral small vessel disease. We included 109 patients with hypertension who underwent extensive neuropsychological assessment, including questionnaires measuring SCF and symptoms of anxiety and depression. Brain magnetic resonance imaging was performed to rate the presence of lacunes, cerebral microbleeds, and perivascular spaces, as well as white matter hyperintensities volume. Results showed significant associations between SCF and objectively measured overall cognition (B=-0.02; 95% confidence interval=-0.03 to -0.005), memory (B=0.02; 95% confidence interval=-0.03 to -0.004), and information processing speed (B=-0.02; 95% confidence interval=-0.03 to -0.001) after adjustment for patient characteristics and vascular risk factors. In addition, SCF were associated with the presence of cerebral microbleeds (odds ratio=1.12; 95% confidence interval=1.02-1.23) after adjustment for patient characteristics and vascular risk factors but not with other imaging markers of cerebral small vessel disease. Our study demonstrates that attention for SCF in patients with hypertension is needed because these may point to lower objective cognitive function, which might be as a result of the presence of cerebral microbleeds. Accordingly, this study emphasizes that neuropsychological assessment and brain imaging need to be considered when patients with hypertension report SCF.

  19. Is Vasomotion in Cerebral Arteries Impaired in Alzheimer’s Disease?

    PubMed Central

    Di Marco, Luigi Yuri; Farkas, Eszter; Martin, Chris; Venneri, Annalena; Frangi, Alejandro F.

    2015-01-01

    Abstract A substantial body of evidence supports the hypothesis of a vascular component in the pathogenesis of Alzheimer’s disease (AD). Cerebral hypoperfusion and blood-brain barrier dysfunction have been indicated as key elements of this pathway. Cerebral amyloid angiopathy (CAA) is a cerebrovascular disorder, frequent in AD, characterized by the accumulation of amyloid-β (Aβ) peptide in cerebral blood vessel walls. CAA is associated with loss of vascular integrity, resulting in impaired regulation of cerebral circulation, and increased susceptibility to cerebral ischemia, microhemorrhages, and white matter damage. Vasomotion— the spontaneous rhythmic modulation of arterial diameter, typically observed in arteries/arterioles in various vascular beds including the brain— is thought to participate in tissue perfusion and oxygen delivery regulation. Vasomotion is impaired in adverse conditions such as hypoperfusion and hypoxia. The perivascular and glymphatic pathways of Aβ clearance are thought to be driven by the systolic pulse. Vasomotion produces diameter changes of comparable amplitude, however at lower rates, and could contribute to these mechanisms of Aβ clearance. In spite of potential clinical interest, studies addressing cerebral vasomotion in the context of AD/CAA are limited. This study reviews the current literature on vasomotion, and hypothesizes potential paths implicating impaired cerebral vasomotion in AD/CAA. Aβ and oxidative stress cause vascular tone dysregulation through direct effects on vascular cells, and indirect effects mediated by impaired neurovascular coupling. Vascular tone dysregulation is further aggravated by cholinergic deficit and results in depressed cerebrovascular reactivity and (possibly) impaired vasomotion, aggravating regional hypoperfusion and promoting further Aβ and oxidative stress accumulation. PMID:25720414

  20. Regulation of cerebral autoregulation by carbon dioxide.

    PubMed

    Meng, Lingzhong; Gelb, Adrian W

    2015-01-01

    Cerebral autoregulation describes a mechanism that maintains cerebral blood flow stable despite fluctuating perfusion pressure. Multiple nonperfusion pressure processes also regulate cerebral perfusion. These mechanisms are integrated. The effect of the interplay between carbon dioxide and perfusion pressure on cerebral circulation has not been specifically reviewed. On the basis of the published data and speculation on the aspects that are without supportive data, the authors offer a conceptualization delineating the regulation of cerebral autoregulation by carbon dioxide. The authors conclude that hypercapnia causes the plateau to progressively ascend, a rightward shift of the lower limit, and a leftward shift of the upper limit. Conversely, hypocapnia results in the plateau shifting to lower cerebral blood flows, unremarkable change of the lower limit, and unclear change of the upper limit. It is emphasized that a sound understanding of both the limitations and the dynamic and integrated nature of cerebral autoregulation fosters a safer clinical practice.

  1. Handedness and cerebral anatomical asymmetries in young adult males.

    PubMed

    Hervé, Pierre-Yves; Crivello, Fabrice; Perchey, Guy; Mazoyer, Bernard; Tzourio-Mazoyer, Nathalie

    2006-02-15

    Using voxel-based morphometry, we measured the cerebral anatomical asymmetries in a sample of 56 young right-handed males and then compared voxelwise asymmetry indices of these subjects to those of 56 young left-handed males. In the right-handed, the clusters of grey matter asymmetry corresponding to the leftward occipital petalia and planum temporale asymmetries were retrieved. Strong rightward temporo-parietal asymmetries were also observed, but the rightward grey matter asymmetry in the frontal lobe was less massive than previously described. Group comparisons of left- and right-handed subjects' asymmetry maps, performed at a statistical threshold not corrected for multiple comparisons, revealed significant effects of handedness on this pattern of anatomical asymmetry in frontal regions, notably in the lower central and precentral sulci, and also in the planum temporale, with right-handed subjects being more leftward asymmetric. Concerning white matter, although almost no focal differences between left- and right-handed subjects were detected, volumetric analyses at the hemispheric level revealed a leftward asymmetry, which happened to be significantly less marked in the left-handed. This latter result, together with the pattern of leftward white matter asymmetries, suggested that anatomical correlates of the left hemispheric specialization for language would exist in white matter. In the population we studied, differences in anatomical asymmetry between left- and right-handed subjects provided structural arguments for a greater functional ambilaterality in left-handed subjects.

  2. CLASHING BEAM PARTICLE ACCELERATOR

    DOEpatents

    Burleigh, R.J.

    1961-04-11

    A charged-particle accelerator of the proton synchrotron class having means for simultaneously accelerating two separate contra-rotating particle beams within a single annular magnet structure is reported. The magnet provides two concentric circular field regions of opposite magnetic polarity with one field region being of slightly less diameter than the other. The accelerator includes a deflector means straddling the two particle orbits and acting to collide the two particle beams after each has been accelerated to a desired energy. The deflector has the further property of returning particles which do not undergo collision to the regular orbits whereby the particles recirculate with the possibility of colliding upon subsequent passages through the deflector.

  3. Vibration control in accelerators

    SciTech Connect

    Montag, C.

    2011-01-01

    In the vast majority of accelerator applications, ground vibration amplitudes are well below tolerable magnet jitter amplitudes. In these cases, it is necessary and sufficient to design a rigid magnet support structure that does not amplify ground vibration. Since accelerator beam lines are typically installed at an elevation of 1-2m above ground level, special care has to be taken in order to avoid designing a support structure that acts like an inverted pendulum with a low resonance frequency, resulting in untolerable lateral vibration amplitudes of the accelerator components when excited by either ambient ground motion or vibration sources within the accelerator itself, such as cooling water pumps or helium flow in superconducting magnets. In cases where ground motion amplitudes already exceed the required jiter tolerances, for instance in future linear colliders, passive vibration damping or active stabilization may be considered.

  4. Dielectric assist accelerating structure

    NASA Astrophysics Data System (ADS)

    Satoh, D.; Yoshida, M.; Hayashizaki, N.

    2016-01-01

    A higher-order TM02 n mode accelerating structure is proposed based on a novel concept of dielectric loaded rf cavities. This accelerating structure consists of ultralow-loss dielectric cylinders and disks with irises which are periodically arranged in a metallic enclosure. Unlike conventional dielectric loaded accelerating structures, most of the rf power is stored in the vacuum space near the beam axis, leading to a significant reduction of the wall loss, much lower than that of conventional normal-conducting linac structures. This allows us to realize an extremely high quality factor and a very high shunt impedance at room temperature. A simulation of a 5 cell prototype design with an existing alumina ceramic indicates an unloaded quality factor of the accelerating mode over 120 000 and a shunt impedance exceeding 650 M Ω /m at room temperature.

  5. Wake field acceleration experiments

    SciTech Connect

    Simpson, J.D.

    1988-01-01

    Where and how will wake field acceleration devices find use for other than, possibly, accelerators for high energy physics. I don't know that this can be responsibly answered at this time. What I can do is describe some recent results from an ongoing experimental program at Argonne which support the idea that wake field techniques and devices are potentially important for future accelerators. Perhaps this will spawn expanded interest and even new ideas for the use of this new technology. The Argonne program, and in particular the Advanced Accelerator Test Facility (AATF), has been reported in several fairly recent papers and reports. But because this is a substantially new audience for the subject, I will include a brief review of the program and the facility before describing experiments. 10 refs., 7 figs.

  6. Accelerator on a Chip

    SciTech Connect

    England, Joel

    2014-06-30

    SLAC's Joel England explains how the same fabrication techniques used for silicon computer microchips allowed their team to create the new laser-driven particle accelerator chips. (SLAC Multimedia Communications)

  7. Charged particle accelerator grating

    DOEpatents

    Palmer, R.B.

    1985-09-09

    A readily disposable and replaceable accelerator grating for a relativistic particle accelerator is described. The grating is formed for a plurality of liquid droplets that are directed in precisely positioned jet streams to periodically dispose rows of droplets along the borders of a predetermined particle beam path. A plurality of lasers are used to direct laser beams onto the droplets, at predetermined angles, thereby to excite the droplets to support electromagnetic accelerating resonances on their surfaces. Those resonances operate to accelerate and focus particles moving along the beam path. As the droplets are distorted or destroyed by the incoming radiation, they are replaced at a predetermined frequency by other droplets supplied through the jet streams.

  8. HEAVY ION LINEAR ACCELERATOR

    DOEpatents

    Van Atta, C.M.; Beringer, R.; Smith, L.

    1959-01-01

    A linear accelerator of heavy ions is described. The basic contributions of the invention consist of a method and apparatus for obtaining high energy particles of an element with an increased charge-to-mass ratio. The method comprises the steps of ionizing the atoms of an element, accelerating the resultant ions to an energy substantially equal to one Mev per nucleon, stripping orbital electrons from the accelerated ions by passing the ions through a curtain of elemental vapor disposed transversely of the path of the ions to provide a second charge-to-mass ratio, and finally accelerating the resultant stripped ions to a final energy of at least ten Mev per nucleon.

  9. Principles of Induction Accelerators

    NASA Astrophysics Data System (ADS)

    Briggs*, Richard J.

    The basic concepts involved in induction accelerators are introduced in this chapter. The objective is to provide a foundation for the more detailed coverage of key technology elements and specific applications in the following chapters. A wide variety of induction accelerators are discussed in the following chapters, from the high current linear electron accelerator configurations that have been the main focus of the original developments, to circular configurations like the ion synchrotrons that are the subject of more recent research. The main focus in the present chapter is on the induction module containing the magnetic core that plays the role of a transformer in coupling the pulsed power from the modulator to the charged particle beam. This is the essential common element in all these induction accelerators, and an understanding of the basic processes involved in its operation is the main objective of this chapter. (See [1] for a useful and complementary presentation of the basic principles in induction linacs.)

  10. Accelerator on a Chip

    ScienceCinema

    England, Joel

    2016-07-12

    SLAC's Joel England explains how the same fabrication techniques used for silicon computer microchips allowed their team to create the new laser-driven particle accelerator chips. (SLAC Multimedia Communications)

  11. DIELECTRIC WALL ACCELERATOR TECHNOLOGY

    SciTech Connect

    Sampayan, S; Caporaso, G; Chen, Y; Harris, J; Hawkins, S; Holmes, C; Nelson, S; Poole, B; Rhodes, M; Sanders, D; Sullivan, J; Wang, L; Watson, J

    2007-10-18

    The dielectric wall accelerator (DWA) is a compact pulsed power device where the pulse forming lines, switching, and vacuum wall are integrated into a single compact geometry. For this effort, we initiated a extensive compact pulsed power development program and have pursued the study of switching (gas, oil, laser induced surface flashover and photoconductive), dielectrics (ceramics and nanoparticle composites), pulse forming line topologies (asymmetric and symmetric Blumleins and zero integral pulse forming lines), and multilayered vacuum insulator (HGI) technology. Finally, we fabricated an accelerator cell for test on ETAII (a 5.5 MeV, 2 kA, 70 ns pulsewidth electron beam accelerator). We review our past results and report on the progress of accelerator cell testing.

  12. Amps particle accelerator definition study

    NASA Technical Reports Server (NTRS)

    Sellen, J. M., Jr.

    1975-01-01

    The Particle Accelerator System of the AMPS (Atmospheric, Magnetospheric, and Plasmas in Space) payload is a series of charged particle accelerators to be flown with the Space Transportation System Shuttle on Spacelab missions. In the configuration presented, the total particle accelerator system consists of an energetic electron beam, an energetic ion accelerator, and both low voltage and high voltage plasma acceleration devices. The Orbiter is illustrated with such a particle accelerator system.

  13. Selective effects of aging on brain white matter microstructure: a diffusion tensor imaging tractography study.

    PubMed

    Michielse, Stijn; Coupland, Nick; Camicioli, Richard; Carter, Rawle; Seres, Peter; Sabino, Jennifer; Malykhin, Nikolai

    2010-10-01

    We examined age-related changes in the cerebral white matter. Structural magnetic resonance images (MRIs) and diffusion tensor images (DTIs) were acquired from 69 healthy subjects aged 22-84 years. Quantitative DTI tractography was performed for nine different white matter tracts to determine tract volume, fractional anisotropy (FA), mean diffusivity (MD), axial, and radial diffusivities. We used automated and manual segmentation to determine volumes of gray matter (GM), white mater (WM), cerebrospinal fluid (CSF), and intracranial space. The results showed significant effects of aging on WM, GM, CSF volumes, and selective effects of aging on structural integrity of different white matter tracts. WM of the prefrontal region was the most vulnerable to aging, while temporal lobe connections, cingulum, and parieto-occipital commissural connections showed relative preservation with age. This study was cross-sectional, and therefore, additional longitudinal studies are needed to confirm our findings.

  14. Designing reliability into accelerators

    NASA Astrophysics Data System (ADS)

    Hutton, A.

    1992-07-01

    Future accelerators will have to provide a high degree of reliability. Quality must be designed in right from the beginning and must remain a central theme throughout the project. The problem is similar to the problems facing US industry today, and examples of the successful application of quality engineering will be given. Different aspects of an accelerator project will be addressed: Concept, Design, Motivation, Management Techniques, and Fault Diagnosis. The importance of creating and maintaining a coherent team will be stressed.

  15. Microgravity Acceleration Measurement System

    NASA Technical Reports Server (NTRS)

    Foster, William

    2009-01-01

    Microgravity Acceleration Measurement System (MAMS) is an ongoing study of the small forces (vibrations and accelerations) on the ISS that result from the operation of hardware, crew activities, as well as dockings and maneuvering. Results will be used to generalize the types of vibrations affecting vibration-sensitive experiments. Investigators seek to better understand the vibration environment on the space station to enable future research.

  16. CEBAF Accelerator Achievements

    NASA Astrophysics Data System (ADS)

    Chao, Y. C.; Drury, M.; Hovater, C.; Hutton, A.; Krafft, G. A.; Poelker, M.; Reece, C.; Tiefenback, M.

    2011-05-01

    In the past decade, nuclear physics users of Jefferson Lab's Continuous Electron Beam Accelerator Facility (CEBAF) have benefited from accelerator physics advances and machine improvements. As of early 2011, CEBAF operates routinely at 6 GeV, with a 12 GeV upgrade underway. This article reports highlights of CEBAF's scientific and technological evolution in the areas of cryomodule refurbishment, RF control, polarized source development, beam transport for parity experiments, magnets and hysteresis handling, beam breakup, and helium refrigerator operational optimization.

  17. Breakthrough: Fermilab Accelerator Technology

    ScienceCinema

    None

    2016-07-12

    There are more than 30,000 particle accelerators in operation around the world. At Fermilab, scientists are collaborating with other laboratories and industry to optimize the manufacturing processes for a new type of powerful accelerator that uses superconducting niobium cavities. Experimenting with unique polishing materials, a Fermilab team has now developed an efficient and environmentally friendly way of creating cavities that can propel particles with more than 30 million volts per meter.

  18. Rolamite acceleration sensor

    DOEpatents

    Abbin, Joseph P.; Briner, Clifton F.; Martin, Samuel B.

    1993-01-01

    A rolamite acceleration sensor which has a failsafe feature including a housing, a pair of rollers, a tension band wrapped in an S shaped fashion around the rollers, wherein the band has a force-generation cut out and a failsafe cut out or weak portion. The failsafe cut out or weak portion breaks when the sensor is subjected to an excessive acceleration so that the sensor fails in an open circuit (non-conducting) state permanently.

  19. Rolamite acceleration sensor

    DOEpatents

    Abbin, J.P.; Briner, C.F.; Martin, S.B.

    1993-12-21

    A rolamite acceleration sensor is described which has a failsafe feature including a housing, a pair of rollers, a tension band wrapped in an S shaped fashion around the rollers, wherein the band has a force-generation cut out and a failsafe cut out or weak portion. The failsafe cut out or weak portion breaks when the sensor is subjected to an excessive acceleration so that the sensor fails in an open circuit (non-conducting) state permanently. 6 figures.

  20. Collective field accelerator

    DOEpatents

    Luce, John S.

    1978-01-01

    A collective field accelerator which operates with a vacuum diode and utilizes a grooved cathode and a dielectric anode that operates with a relativistic electron beam with a .nu./.gamma. of .about. 1, and a plurality of dielectric lenses having an axial magnetic field thereabout to focus the collectively accelerated electrons and ions which are ejected from the anode. The anode and lenses operate as unoptimized r-f cavities which modulate and focus the beam.

  1. Positron emission tomography in the newborn: extensive impairment of regional cerebral blood flow with intraventricular hemorrhage and hemorrhagic intracerebral involvement

    SciTech Connect

    Volpe, J.J.; Herscovitch, P.; Perlman, J.M.; Raichle, M.E.

    1983-11-01

    Positron emission tomography (PET) now provides the capability of measuring regional cerebral blood flow with high resolution and little risk. In this study, we utilized PET in six premature infants (920 to 1,200 g) with major intraventricular hemorrhage and hemorrhagic intracerebral involvement to measure regional cerebral blood flow during the acute period (5 to 17 days of age). Cerebral blood flow was determined after intravenous injection of H/sub 2/O, labeled with the positron-emitting isotope, /sup 15/O. Findings were similar and dramatic in all six infants. In the area of hemorrhagic intracerebral involvement, little or no cerebral blood flow was detected. However, in addition, surprisingly, a marked two- to fourfold reduction in cerebral blood flow was observed throughout the affected hemisphere, well posterior and lateral to the intracerebral hematoma, including cerebral white matter and, to a lesser extent, frontal, temporal, and parietal cortex. In the one infant studied a second time, ie, at 3 months of age, the extent and severity of the decreased cerebral blood flows in the affected hemisphere were similar to those observed on the study during the neonatal period. At the three autopsies, the affected left hemisphere showed extensive infarction, corroborating the PET scans. These observations, the first demonstration of the use of PET in the determination of regional cerebral blood flow in the newborn, show marked impairments in regional cerebral blood flow in the hemisphere containing an apparently restricted intracerebral hematoma, indicating that the hemorrhagic intracerebral involvement is only a component of a much larger lesion, ischemic in basic nature, ie, an infarction. This large ischemic lesion explains the poor neurologic outcome in infants with intraventricular hemorrhage and hemorrhagic intracerebral involvement.

  2. Periventricular White Matter Is a Nexus for Network Connectivity in the Human Brain.

    PubMed

    Owen, Julia P; Wang, Maxwell B; Mukherjee, Pratik

    2016-09-01

    The edges of the structural connectome traverse the white matter to connect cortical and subcortical nodes, although the anatomic embedding of these edges is generally overlooked in the literature. Characterization of the geometry of the structural connectome could provide an improved understanding of the relative importance of various white matter regions to the network architecture of the human brain in normal development and aging, as well as in white matter diseases with regionally specific patterns of vulnerability. Edge density imaging (EDI) has previously been used to show that the posterior periventricular white matter contains a disproportionately large number of connectome edges. In this study, the regional distribution of connectome edges within cerebral white matter, including the importance of posterior periventricular white matter, is further investigated and demonstrated to be invariant to different gray matter parcellations and different diffusion MRI acquisition and postprocessing/tractography methods. An examination of the highest k-core edges and a virtual lesion analysis illuminate hemispheric asymmetries (left>right) in the embedding of connectome edges. Therefore, EDI reveals specific areas of vulnerability within the white matter connectivity of the human brain, especially in the periventricular white matter. The idea of a periventricular nexus fits with the known neurobiology of brain development and may result from simple geometrical considerations in minimizing wiring cost in structural brain connectivity.

  3. Disrupted white matter in language and motor tracts in developmental stuttering.

    PubMed

    Connally, Emily L; Ward, David; Howell, Peter; Watkins, Kate E

    2014-04-01

    White matter tracts connecting areas involved in speech and motor control were examined using diffusion-tensor imaging in a sample of people who stutter (n=29) who were heterogeneous with respect to age, sex, handedness and stuttering severity. The goals were to replicate previous findings in developmental stuttering and to extend our knowledge by evaluating the relationship between white matter differences in people who stutter and factors such as age, sex, handedness and stuttering severity. We replicated previous findings that showed reduced integrity in white matter underlying ventral premotor cortex, cerebral peduncles and posterior corpus callosum in people who stutter relative to controls. Tractography analysis additionally revealed significantly reduced white matter integrity in the arcuate fasciculus bilaterally and the left corticospinal tract and significantly reduced connectivity within the left corticobulbar tract in people who stutter. Region-of-interest analyses revealed reduced white matter integrity in people who stutter in the three pairs of cerebellar peduncles that carry the afferent and efferent fibers of the cerebellum. Within the group of people who stutter, the higher the stuttering severity index, the lower the white matter integrity in the left angular gyrus, but the greater the white matter connectivity in the left corticobulbar tract. Also, in people who stutter, handedness and age predicted the integrity of the corticospinal tract and peduncles, respectively. Further studies are needed to determine which of these white matter differences relate to the neural basis of stuttering and which reflect experience-dependent plasticity.

  4. 'Snow White' Trench

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This image was acquired by NASA's Phoenix Mars Lander's Surface Stereo Imager on Sol 43, the 43rd Martian day after landing (July 8, 2008). This image shows the trench informally called 'Snow White.'

    Two samples were delivered to the Wet Chemistry Laboratory, which is part of Phoenix's Microscopy, Electrochemistry, and Conductivity Analyzer (MECA). The first sample was taken from the surface area just left of the trench and informally named 'Rosy Red.' It was delivered to the Wet Chemistry Laboratory on Sol 30 (June 25, 2008). The second sample, informally named 'Sorceress,' was taken from the center of the 'Snow White' trench and delivered to the Wet Chemistry Laboratory on Sol 41 (July 6, 2008).

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  5. White Dwarf Mass Distribution

    NASA Astrophysics Data System (ADS)

    Kepler, S. O.; Koester, D.; Romero, A. D.; Ourique, G.; Pelisoli, I.

    2017-03-01

    We present the mass distribution for all S/N ≥ 15 DA white dwarfs detected in the Sloan Digital Sky Survey up to Data Release 12 in 2015, fitted with Koester models for ML2/α=0.8 (Teff≥ 10000 K), and for DBs with S/N ≥ 10, fitted with ML2/α=1.25, for Teff >16 000 K. These mass distributions are for logg≥6.5 stars, i.e., excluding the Extremely Low Mass white dwarfs. We also present the mass distributions corrected by volume with the 1/Vmax approach, for stars brighter than g=19. Both distributions have a maximum at M=0.624 M ⊙ but very distinct shapes.

  6. White matter involvement in chronic musculoskeletal pain

    PubMed Central

    Lieberman, Gregory; Shpaner, Marina; Watts, Richard; Andrews, Trevor; Filippi, Christopher G.; Davis, Marcia; Naylor, Magdalena R.

    2014-01-01

    There is emerging evidence that chronic musculoskeletal pain is associated with anatomical and functional abnormalities in gray matter. However, little research has investigated the relationship between chronic musculoskeletal pain and white matter (WM). In this study, we used whole-brain tract-based spatial statistics, and region-of-interest analyses of diffusion tensor imaging (DTI) data to demonstrate that patients with chronic musculoskeletal pain exhibit several abnormal WM integrity as compared to healthy controls. Chronic musculoskeletal pain was associated with lower fractional anisotropy (FA) in the splenium of corpus callosum, and left cingulum adjacent to the hippocampus. Patients also had higher radial diffusivity (RD) in the splenium, right anterior and posterior limbs of internal capsule, external capsule, superior longitudinal fasciculus, and cerebral peduncle. Patterns of axial diffusivity (AD) varied: patients exhibited lower AD in the left cingulum adjacent to the hippocampus and higher AD bilaterally in the anterior limbs of internal capsule, and in the right cerebral peduncle. Several correlations between diffusion metrics and clinical variables were also significant at a p<0.01 level: FA in the left uncinate fasciculus correlated positively with Total Pain Experience and typical levels of pain severity. AD in the left anterior limb of internal capsule and left uncinate fasciculus were correlated with Total Pain Experience and typical pain level. Positive correlations were also found between AD in the right uncinate and both Total Pain Experience and Pain Catastrophizing. These results demonstrate that WM abnormalities play a role in chronic musculoskeletal pain; either as a cause, predisposing factor, consequence, or compensatory adaptation. PMID:25135468

  7. Accelerators for America's Future

    NASA Astrophysics Data System (ADS)

    Bai, Mei

    2016-03-01

    Particle accelerator, a powerful tool to energize beams of charged particles to a desired speed and energy, has been the working horse for investigating the fundamental structure of matter and fundermental laws of nature. Most known examples are the 2-mile long Stanford Linear Accelerator at SLAC, the high energy proton and anti-proton collider Tevatron at FermiLab, and Large Hadron Collider that is currently under operation at CERN. During the less than a century development of accelerator science and technology that led to a dazzling list of discoveries, particle accelerators have also found various applications beyond particle and nuclear physics research, and become an indispensible part of the economy. Today, one can find a particle accelerator at almost every corner of our lives, ranging from the x-ray machine at the airport security to radiation diagnostic and therapy in hospitals. This presentation will give a brief introduction of the applications of this powerful tool in fundermental research as well as in industry. Challenges in accelerator science and technology will also be briefly presented

  8. Biomedical accelerator mass spectrometry

    NASA Astrophysics Data System (ADS)

    Freeman, Stewart P. H. T.; Vogel, John S.

    1995-05-01

    Ultrasensitive SIMS with accelerator based spectrometers has recently begun to be applied to biomedical problems. Certain very long-lived radioisotopes of very low natural abundances can be used to trace metabolism at environmental dose levels ( [greater-or-equal, slanted] z mol in mg samples). 14C in particular can be employed to label a myriad of compounds. Competing technologies typically require super environmental doses that can perturb the system under investigation, followed by uncertain extrapolation to the low dose regime. 41Ca and 26Al are also used as elemental tracers. Given the sensitivity of the accelerator method, care must be taken to avoid contamination of the mass spectrometer and the apparatus employed in prior sample handling including chemical separation. This infant field comprises the efforts of a dozen accelerator laboratories. The Center for Accelerator Mass Spectrometry has been particularly active. In addition to collaborating with groups further afield, we are researching the kinematics and binding of genotoxins in-house, and we support innovative uses of our capability in the disciplines of chemistry, pharmacology, nutrition and physiology within the University of California. The field can be expected to grow further given the numerous potential applications and the efforts of several groups and companies to integrate more the accelerator technology into biomedical research programs; the development of miniaturized accelerator systems and ion sources capable of interfacing to conventional HPLC and GMC, etc. apparatus for complementary chemical analysis is anticipated for biomedical laboratories.

  9. Bahamian whitings - no fish story

    SciTech Connect

    Shinn, E.A.; Steinen, R.P.; Lidz, B.H.; Halley, R.B.

    1985-02-01

    Bahamian whitings, controversial patches of drifting mud-laden water, have been thought to be produced by fish. Observations over several 7-day periods show that whitings are long-lived phenomena (days and possibly weeks) and that the dozens which exist at any time on the Great Bahama Bank continually rain aragonitic sediment. Although chemical changes consistent with precipitation have not been detected in seawater near or within whitings, new data indirectly suggest that precipitation from seawater causes whitings. Lime mud settled in approximately 6 hr in large (30 gal) containers of water taken from whitings, whereas in the sea, the parent whitings persisted for days. Sediment traps verified continual transport of sediment. Divers noted no fish stirring up the bottom nor any evidence of bottom feeding. Side-scan sonar failed to detect unusually large schools of fish, and a shrimper's net dragged in the whitings failed to catch any fish known to be bottom feeders. Dragging the net in clear water near active whitings created artificial whitings that settled back to the bottom in a few hours. Current measurements within and outside of whitings ruled out current eddies. Near the edge of the Bahama platform, whitings occur over bottom sediments too coarse-grained to be stirred into suspension, yet the muddy bottom of the banks was miles away. These data suggest that natural whitings must be continually replenished with sediment. Filtration of known volumes of water from 15 whitings and from clear seawater indicates that active-whiting water contains only a very small (10-12 mg/L) amount of suspended carbonate sediment, yet whitings are considered a potential major source of lime mud on the Great Bahama Bank. Inasmuch as nearly one-half the world's oil is pumped from limestone, knowledge of the origin and deposition of lime mud has implications for hydrocarbon exploration.

  10. Differential effects of white noise in cognitive and perceptual tasks.

    PubMed

    Herweg, Nora A; Bunzeck, Nico

    2015-01-01

    Beneficial effects of noise on higher cognition have recently attracted attention. Hypothesizing an involvement of the mesolimbic dopamine system and its functional interactions with cortical areas, the current study aimed to demonstrate a facilitation of dopamine-dependent attentional and mnemonic functions by externally applying white noise in five behavioral experiments including a total sample of 167 healthy human subjects. During working memory, acoustic white noise impaired accuracy when presented during the maintenance period (Experiments 1-3). In a reward based long-term memory task, white noise accelerated perceptual judgments for scene images during encoding but left subsequent recognition memory unaffected (Experiment 4). In a modified Posner task (Experiment 5), the benefit due to white noise in attentional orienting correlated weakly with reward dependence, a personality trait that has been associated with the dopaminergic system. These results suggest that white noise has no general effect on cognitive functions. Instead, they indicate differential effects on perception and cognition depending on a variety of factors such as task demands and timing of white noise presentation.

  11. Cognitive correlates of white matter lesion load and brain atrophy

    PubMed Central

    Dong, Chuanhui; Nabizadeh, Nooshin; Caunca, Michelle; Cheung, Ying Kuen; Rundek, Tatjana; Elkind, Mitchell S.V.; DeCarli, Charles; Sacco, Ralph L.; Stern, Yaakov

    2015-01-01

    Objective: We investigated white matter lesion load and global and regional brain volumes in relation to domain-specific cognitive performance in the stroke-free Northern Manhattan Study (NOMAS) population. Methods: We quantified white matter hyperintensity volume (WMHV), total cerebral volume (TCV), and total lateral ventricular (TLV) volume, as well as hippocampal and cortical gray matter (GM) lobar volumes in a subgroup. We used general linear models to examine MRI markers in relation to domain-specific cognitive performance, adjusting for key covariates. Results: MRI and cognitive data were available for 1,163 participants (mean age 70 ± 9 years; 60% women; 66% Hispanic, 17% black, 15% white). Across the entire sample, those with greater WMHV had worse processing speed. Those with larger TLV volume did worse on episodic memory, processing speed, and semantic memory tasks, and TCV did not explain domain-specific variability in cognitive performance independent of other measures. Age was an effect modifier, and stratified analysis showed that TCV and WMHV explained variability in some domains above age 70. Smaller hippocampal volume was associated with worse performance across domains, even after adjusting for APOE ε4 and vascular risk factors, whereas smaller frontal lobe volumes were only associated with worse executive function. Conclusions: In this racially/ethnically diverse, community-based sample, white matter lesion load was inversely associated with cognitive performance, independent of brain atrophy. Lateral ventricular, hippocampal, and lobar GM volumes explained domain-specific variability in cognitive performance. PMID:26156514

  12. [The White Book].

    PubMed

    Rouger, P

    2008-11-01

    It is necessary for European countries to have references and guidelines to cope with the wide field of blood transfusion. It is the institutions and professionals' role to provide for technical specifications linked to the collection, qualification, preparation, storage and distribution of labile blood products. In this context, EuroNet-TMS publishes every five year (2005, 2010...) a White Book meant to issue statements on the current situation, activities in progress in Europe and future developments.

  13. Snow White Trenches

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This image was acquired by NASA's Phoenix Mars Lander's Surface Stereo Imager on the 25th Martian day of the mission, or Sol 24 (June 19, 2008), after the May 25, 2008, landing. This image shows the trenches informally called 'Snow White 1' (left) and 'Snow White 2' (right). The trench is about 5 centimeters (2 inches) deep and 30 centimeters (12 inches) long.

    'Snow White' is located in a patch of Martian soil near the center of a polygonal surface feature, nicknamed 'Cheshire Cat.' The 'dump pile' is located at the top of the trench, the side farthest away from the lander, and has been dubbed 'Croquet Ground.' The digging site has been named 'Wonderland.'

    This image has been enhanced to brighten shaded areas.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  14. Convection in White Dwarfs

    NASA Astrophysics Data System (ADS)

    Provencal, Judith L.; Shipman, H.; Dalessio, J.; M, M.

    2012-01-01

    Convection is one of the largest sources of theoretical uncertainty in our understanding of stellar physics. Current studies of convective energy transport are based on the mixing length theory. Originally intended to depict turbulent flows in engineering situations, MLT enjoys moderate success in describing stellar convection. However, problems arising from MLT's incompleteness are apparent in studies ranging from determinations of the ages of massive stars, to understanding the structure F and early A stars, to predicting the pulsation periods of solar stars, to understanding the atmosphere of Titan. As an example for white dwarfs, Bergeron et al. (1995) show that model parameters such as flux, line profiles, energy distribution, color indices, and equivalent widths are extremely sensitive to the assumed MLT parameterization. The authors find systematic uncertainties ranging from 25% for effective temperatures to 11% for mass and radius. The WET is engaged in a long term project to empirically determine the physical properties of convection in the atmospheres of pulsating white dwarfs. The technique, outlined by Montgomery et al. (2010), uses information from nonlinear (non-sinusoidal) pulse shapes of the target star to empirically probe the physical properties of its convection zone. Approximately two thirds of all white dwarfs show nonlinear characteristics in their light curves. We present current results from WET targets in 2008-2011.

  15. Decoding white coat hypertension

    PubMed Central

    Bloomfield, Dennis A; Park, Alex

    2017-01-01

    There is arguably no less understood or more intriguing problem in hypertension that the “white coat” condition, the standard concept of which is significantly blood pressure reading obtained by medical personnel of authoritative standing than that obtained by more junior and less authoritative personnel and by the patients themselves. Using hospital-initiated ambulatory blood pressure monitoring, the while effect manifests as initial and ending pressure elevations, and, in treated patients, a low daytime profile. The effect is essentially systolic. Pure diastolic white coat hypertension appears to be exceedingly rare. On the basis of the studies, we believe that the white coat phenomenon is a common, periodic, neuro-endocrine reflex conditioned by anticipation of having the blood pressure taken and the fear of what this measurement may indicate concerning future illness. It does not change with time, or with prolonged association with the physician, particularly with advancing years, it may be superimposed upon essential hypertension, and in patients receiving hypertensive medication, blunting of the nighttime dip, which occurs in about half the patients, may be a compensatory mechanisms, rather than an indication of cardiovascular risk. Rather than the blunted dip, the morning surge or the widened pulse pressure, cardiovascular risk appears to be related to elevation of the average night time pressure. PMID:28352632

  16. Axon-glia synapses are highly vulnerable to white matter injury in the developing brain.

    PubMed

    Shen, Yan; Liu, Xiao-Bo; Pleasure, David E; Deng, Wenbin

    2012-01-01

    The biology of cerebral white matter injury has been woefully understudied, in part because of the difficulty of reliably modeling this type of injury in rodents. Periventricular leukomalacia (PVL) is the predominant form of brain injury and the most common cause of cerebral palsy in premature infants. PVL is characterized by predominant white matter injury. No specific therapy for PVL is presently available, because the pathogenesis is not well understood. Here we report that two types of mouse PVL models have been created by hypoxia-ischemia with or without systemic coadministration of lipopolysaccharide (LPS). LPS coadministration exacerbated hypoxic-ischemic white matter injury and led to enhanced microglial activation and astrogliosis. Drug trials with the antiinflammatory agent minocycline, the antiexcitotoxic agent NBQX, and the antioxidant agent edaravone showed various degrees of protection in the two models, indicating that excitotoxic, oxidative, and inflammatory forms of injury are involved in the pathogenesis of injury to immature white matter. We then applied immunoelectron microscopy to reveal fine structural changes in the injured white matter and found that synapses between axons and oligodendroglial precursor cells (OPCs) are quickly and profoundly damaged. Hypoxia-ischemia caused a drastic decrease in the number of postsynaptic densities associated with the glutamatergic axon-OPC synapses defined by the expression of vesicular glutamate transporters, vGluT1 and vGluT2, on axon terminals that formed contacts with OPCs in the periventricular white matter, resulted in selective shrinkage of the postsynaptic OPCs contacted by vGluT2 labeled synapses, and led to excitotoxicity mediated by GluR2-lacking, Ca(2+) -permeable AMPA receptors. Overall, the present study provides novel mechanistic insights into the pathogenesis of PVL and reveals that axon-glia synapses are highly vulnerable to white matter injury in the developing brain. More broadly, the

  17. White matter changes in chronic alcoholic liver disease: Hypothesized association and putative biochemical mechanisms.

    PubMed

    Hathout, Leith; Huang, Jimmy; Zamani, Amir; Morioka, Craig; El-Saden, Suzie

    2015-12-01

    Advanced liver disease has long been associated with cerebral abnormalities. These abnormalities, termed acquired hepatocerebral degeneration, are typically visualized as T1 weighted hyperintensity on MRI in the deep gray matter of the basal ganglia. Recent reports, however, have demonstrated that a subset of patients with chronic alcoholic liver disease may also develop white matter abnormalities. Thus far, the morphology of these changes is not well characterized. Previous studies have described these changes as patchy, sporadic white matter abnormalities but have not posited localization of these changes to any particular white matter tracts. This paper hypothesizes that the white matter findings associated with advanced alcoholic liver disease localize to the corticocerebellar tracts. As an initial investigation of this hypothesis, 78 patients with a diagnosis of liver cirrhosis and an MRI showing clearly abnormal T1 weighted hyperintensity in the bilateral globus pallidus, characteristic of chronic liver disease, were examined for white matter signal abnormalities in the corticocerebellar tracts using FLAIR and T2 weighted images. The corticocerebellar tracts were subdivided into two regions: periventricular white matter (consisting of the sum of the centrum-semiovale and corona radiata), and lower white matter (consisting of the corona radiata, internal capsules, middle cerebral peduncles, middle cerebellar peduncles and cerebellum). As compared to matched controls, significantly greater signal abnormalities in both the periventricular white matter and lower white matter regions of the corticocerebellar tracts were observed in patients with known liver cirrhosis and abnormal T1 W hyperintensity in the globi pallidi. This difference was most pronounced in the lower white matter region of the corticocerebellar tract, with statistical significance of p<0.0005. Furthermore, the pathophysiologic mechanism underlying these changes remains unknown. This paper

  18. Selective cerebral perfusion for cerebral protection: what we do know

    PubMed Central

    Tang, Gilbert H. L.

    2013-01-01

    Selective antegrade cerebral perfusion (SACP) for aortic arch surgery has evolved considerably since it was first reported. Various pressure rates have been investigated through animal models, as has the effect of warmer perfusate temperatures and hematocrit. Clinical research into pH management, the role of unilateral and bilateral perfusion, and core temperatures have further refined the procedure. We recommend the following protocol for SACP: perfusion pressure between 40-60 mmHg, flow rates between 6-10 mL/kg/min, and perfusate temperature of 20-28 °C; core cooling to 18-30 °C contingent on duration of arrest; alpha-stat pH management; hematocrit between 25-30%; near infrared spectroscopy to monitor cerebral perfusion; and bilateral perfusion when prolonged durations of SACP is anticipated. PMID:23977601

  19. Revisiting GRACE Antarctic ice mass trends and accelerations considering autocorrelation

    NASA Astrophysics Data System (ADS)

    Williams, Simon D. P.; Moore, Philip; King, Matt A.; Whitehouse, Pippa L.

    2014-01-01

    Previous GRACE-derived ice mass trends and accelerations have almost entirely been based on an assumption that the residuals to a regression model (including also semi-annual, annual and tidal aliasing terms) are not serially correlated. We consider ice mass change time series for Antarctica and show that significant autocorrelation is, in fact, present. We examine power-law and autoregressive models and compare them to those that assume white (uncorrelated) noise. The data do not let us separate autoregressive and power-law models but both indicate that white noise uncertainties need to be scaled up by a factor of up to 4 for accelerations and 6 for linear rates, depending on length of observations and location. For the whole of Antarctica, East Antarctica and West Antarctica the scale factors are 1.5, 1.5 and 2.2 respectively for the trends and, for the accelerations, 1.5, 1.5 and 2.1. Substantially lower scale-factors are required for offshore time series, suggesting much of the time-correlation is related to continental mass changes. Despite the higher uncertainties, we find significant (2-sigma) accelerations over much of West Antarctica (overall increasing mass loss) and Dronning Maud Land (increasing mass gain) as well as a marginally significant acceleration for the ice sheet as a whole (increasing mass loss).

  20. Laser Ion Acceleration Control

    NASA Astrophysics Data System (ADS)

    Kawata, Shigeo; Nagashima, T.; Izumiyama, T.; Sato, D.; Takano, M.; Barada, D.; Ma, Y. Y.; Gu, Y. J.; Kong, Q.; Wang, P. X.; Wang, W. M.

    2013-10-01

    An intense femtosecond pulsed laser is employed to accelerate ions. The issues in the laser ion accelerator include the energy efficiency from the laser to the ions, the ion beam collimation, the ion energy spectrum control, the ion beam bunching, the ion particle energy control, etc. In the study particle computer simulations were performed to solve the issues, and each component was designed to control the ion beam quality. When an intense laser illuminates a target, electrons in the target are accelerated and leave from the target; temporarily a strong electric field is formed between the high-energy electrons and the target ions, and the target ions are accelerated. The energy efficiency from the laser to ions was improved by using a solid target with a fine sub-wavelength structure or by a near critical density gas plasma. The ion beam collimation was realized by holes behind the solid target. The control of the ion energy spectrum and the ion particle energy, and the ion beam bunching were successfully realized by a multi-stage laser-target interaction. The present study proposed a novel concept for a future compact laser ion accelerator, based on each component study required to control the ion beam quality and parameters. Partly supported by JSPS, MEXT, CORE, Japan/US Cooperation program, ASHULA and ILE/Osaka University.

  1. Dielectric laser accelerators

    NASA Astrophysics Data System (ADS)

    England, R. Joel; Noble, Robert J.; Bane, Karl; Dowell, David H.; Ng, Cho-Kuen; Spencer, James E.; Tantawi, Sami; Wu, Ziran; Byer, Robert L.; Peralta, Edgar; Soong, Ken; Chang, Chia-Ming; Montazeri, Behnam; Wolf, Stephen J.; Cowan, Benjamin; Dawson, Jay; Gai, Wei; Hommelhoff, Peter; Huang, Yen-Chieh; Jing, Chunguang; McGuinness, Christopher; Palmer, Robert B.; Naranjo, Brian; Rosenzweig, James; Travish, Gil; Mizrahi, Amit; Schachter, Levi; Sears, Christopher; Werner, Gregory R.; Yoder, Rodney B.

    2014-10-01

    The use of infrared lasers to power optical-scale lithographically fabricated particle accelerators is a developing area of research that has garnered increasing interest in recent years. The physics and technology of this approach is reviewed, which is referred to as dielectric laser acceleration (DLA). In the DLA scheme operating at typical laser pulse lengths of 0.1 to 1 ps, the laser damage fluences for robust dielectric materials correspond to peak surface electric fields in the GV /m regime. The corresponding accelerating field enhancement represents a potential reduction in active length of the accelerator between 1 and 2 orders of magnitude. Power sources for DLA-based accelerators (lasers) are less costly than microwave sources (klystrons) for equivalent average power levels due to wider availability and private sector investment. Because of the high laser-to-particle coupling efficiency, required pulse energies are consistent with tabletop microJoule class lasers. Combined with the very high (MHz) repetition rates these lasers can provide, the DLA approach appears promising for a variety of applications, including future high-energy physics colliders, compact light sources, and portable medical scanners and radiative therapy machines.

  2. Electrostatic Plasma Accelerator (EPA)

    NASA Technical Reports Server (NTRS)

    Brophy, John R.; Aston, Graeme

    1989-01-01

    The Electrostatic Plasma Accelerator (EPA) is a thruster concept which promises specific impulse levels between low power arcjets and those of the ion engine while retaining the relative simplicity of the arcjet. The EPA thruster produces thrust through the electrostatic acceleration of a moderately dense plasma. No accelerating electrodes are used and the specific impulse is a direct function of the applied discharge voltage and the propellant atomic mass. The goal of the present program is to demonstrate feasibility of the EPA thruster concept through experimental and theoretical investigations of the EPA acceleration mechanism and discharge chamber performance. Experimental investigations will include operating the test bed ion (TBI) engine as an EPA thruster and parametrically varying the thruster geometry and operating conditions to quantify the electrostatic plasma acceleration effect. The theoretical investigations will include the development of a discharge chamber model which describes the relationships between the engine size, plasma properties, and overall performance. For the EPA thruster to be a viable propulsion concept, overall thruster efficiencies approaching 30% with specific impulses approaching 1000 s must be achieved.

  3. Advanced accelerator theory development

    SciTech Connect

    Sampayan, S.E.; Houck, T.L.; Poole, B.; Tishchenko, N.; Vitello, P.A.; Wang, I.

    1998-02-09

    A new accelerator technology, the dielectric wall accelerator (DWA), is potentially an ultra compact accelerator/pulsed power driver. This new accelerator relies on three new components: the ultra-high gradient insulator, the asymmetric Blumlein and low jitter switches. In this report, we focused our attention on the first two components of the DWA system the insulators and the asymmetric Blumlein. First, we sought to develop the necessary design tools to model and scale the behavior of the high gradient insulator. To perform this task we concentrated on modeling the discharge processes (i.e., initiation and creation of the surface discharge). In addition, because these high gradient structures exhibit favorable microwave properties in certain accelerator configurations, we performed experiments and calculations to determine the relevant electromagnetic properties. Second, we performed circuit modeling to understand energy coupling to dynamic loads by the asymmetric Blumlein. Further, we have experimentally observed a non-linear coupling effect in certain asymmetric Blumlein configurations. That is, as these structures are stacked into a complete module, the output voltage does not sum linearly and a lower than expected output voltage results. Although we solved this effect experimentally, we performed calculations to understand this effect more fully to allow better optimization of this DWA pulse-forming line system.

  4. Animal models of cerebral ischemia

    NASA Astrophysics Data System (ADS)

    Khodanovich, M. Yu.; Kisel, A. A.

    2015-11-01

    Cerebral ischemia remains one of the most frequent causes of death and disability worldwide. Animal models are necessary to understand complex molecular mechanisms of brain damage as well as for the development of new therapies for stroke. This review considers a certain range of animal models of cerebral ischemia, including several types of focal and global ischemia. Since animal models vary in specificity for the human disease which they reproduce, the complexity of surgery, infarct size, reliability of reproduction for statistical analysis, and adequate models need to be chosen according to the aim of a study. The reproduction of a particular animal model needs to be evaluated using appropriate tools, including the behavioral assessment of injury and non-invasive and post-mortem control of brain damage. These problems also have been summarized in the review.

  5. Plasma-based accelerator structures

    SciTech Connect

    Schroeder, Carl B.

    1999-12-01

    Plasma-based accelerators have the ability to sustain extremely large accelerating gradients, with possible high-energy physics applications. This dissertation further develops the theory of plasma-based accelerators by addressing three topics: the performance of a hollow plasma channel as an accelerating structure, the generation of ultrashort electron bunches, and the propagation of laser pulses is underdense plasmas.

  6. Microinfarct disruption of white matter structure

    PubMed Central

    Auriel, Eitan; Edlow, Brian L.; Reijmer, Yael D.; Fotiadis, Panagiotis; Ramirez-Martinez, Sergi; Ni, Jun; Reed, Anne K.; Vashkevich, Anastasia; Schwab, Kristin; Rosand, Jonathan; Viswanathan, Anand; Wu, Ona; Gurol, M. Edip

    2014-01-01

    Objective: To evaluate the local effect of small asymptomatic infarctions detected by diffusion-weighted imaging (DWI) on white matter microstructure using longitudinal structural and diffusion tensor imaging (DTI). Methods: Nine acute to subacute DWI lesions were identified in 6 subjects with probable cerebral amyloid angiopathy who had undergone high-resolution MRI both before and after DWI lesion detection. Regions of interest (ROIs) corresponding to the site of the DWI lesion (lesion ROI) and corresponding site in the nonlesioned contralateral hemisphere (control ROI) were coregistered to the pre- and postlesional scans. DTI tractography was additionally performed to reconstruct the white matter tracts containing the ROIs. DTI parameters (fractional anisotropy [FA], mean diffusivity [MD]) were quantified within each ROI, the 6-mm lesion-containing tract segments, and the entire lesion-containing tract bundle. Lesion/control FA and MD ratios were compared across time points. Results: The postlesional scans (performed a mean 7.1 ± 4.7 months after DWI lesion detection) demonstrated a decrease in median FA lesion/control ROI ratio (1.08 to 0.93, p = 0.038) and increase in median MD lesion/control ROI ratio (0.97 to 1.17, p = 0.015) relative to the prelesional scans. There were no visible changes on postlesional high-resolution T1-weighted and fluid-attenuated inversion recovery images in 4 of 9 lesion ROIs and small (2–5 mm) T1 hypointensities in the remaining 5. No postlesional changes in FA or MD ratios were detected in the 6-mm lesion-containing tract segments or full tract bundles. Conclusions: Asymptomatic DWI lesions produce chronic local microstructural injury. The cumulative effects of these widely distributed lesions may directly contribute to small-vessel–related vascular cognitive impairment. PMID:24920857

  7. White vegetables: glycemia and satiety.

    PubMed

    Anderson, G Harvey; Soeandy, Chesarahmia Dojo; Smith, Christopher E

    2013-05-01

    The objective of this review is to discuss the effect of white vegetable consumption on glycemia, satiety, and food intake. White vegetables is a term used to refer to vegetables that are white or near white in color and include potatoes, cauliflowers, turnips, onions, parsnips, white corn, kohlrabi, and mushrooms (technically fungi but generally considered a vegetable). They vary greatly in their contribution to the energy and nutrient content of the diet and glycemia and satiety. As with other foods, the glycemic effect of many white vegetables has been measured. The results illustrate that interpretation of the semiquantitative comparative ratings of white vegetables as derived by the glycemic index must be context dependent. As illustrated by using the potato as an example, the glycemic index of white vegetables can be misleading if not interpreted in the context of the overall contribution that the white vegetable makes to the carbohydrate and nutrient composition of the diet and their functionality in satiety and metabolic control within usual meals. It is concluded that application of the glycemic index in isolation to judge the role of white vegetables in the diet and, specifically in the case of potato as consumed in ad libitum meals, has led to premature and possibly counterproductive dietary guidance.

  8. Ginkgo biloba for cerebral insufficiency.

    PubMed Central

    Kleijnen, J; Knipschild, P

    1992-01-01

    1. By means of a critical review we tried to establish whether there is evidence from controlled trials in humans on the efficacy of Ginkgo biloba extracts in cerebral insufficiency. 2. The methodological quality of 40 trials on Ginkgo and cerebral insufficiency was assessed using a list of predefined criteria of good methodology, and the outcome of the trials was interpreted in relation to their quality. A comparison of the quality was made with trials of co-dergocrine, which is registered for the same indication. 3. There were eight well performed trials out of a total of 40. Shortcomings were limited numbers of patients included, and incomplete description of randomization procedures, patient characteristics, effect measurement and data presentation. In no trial was double-blindness checked. Virtually all trials reported positive results, in most trials the dosage was 120 mg Ginkgo extract a day, given for at least 4-6 weeks. For the best trials, there were no marked differences in the quality of the evidence of the efficacy of Ginkgo in cerebral insufficiency compared with co-dergocrine. The results of the review may be complicated by a combination of publication bias and other biases, because there were no negative results reported in many trials of low methodological quality. 4. Positive results have been reported for Ginkgo biloba extracts in the treatment of cerebral insufficiency. The clinical evidence is similar to that of a registered product which is prescribed for the same indication. However, further studies should be conducted for a more detailed assessment of the efficacy. PMID:1457269

  9. Cerebral Hemodynamics and Vigilance Performance

    DTIC Science & Technology

    2009-01-01

    use of another nonrestrictive and relatively economic alternative to PET and fMRI—the assessment of cerebral blood oxygen saturation using NIRS ( Gratton ...Blackwell Pub- lishers. Gratton , G., & Fabiani, M. (2007). Optical imaging of brain functioning. In R. Parasuraman & M. Rizzo (Eds.), Neuroergonomics: The...Cerebralvascular disorders (3rd ed.). New York: Raven. Toronov, V., Webb, A., Choi, J. H., Wolf, M., Michalos, A., Gratton , E., et al. (2001

  10. [Cerebral artery thrombosis in pregnancy].

    PubMed

    Charco Roca, L M; Ortiz Sanchez, V E; Hernandez Gutierrez-Manchon, O; Quesada Villar, J; Bonmatí García, L; Rubio Postigo, G

    2015-11-01

    A 28 year old woman, ASA I, who, in the final stages of her pregnancy presented with signs of neural deficit that consisted of distortion of the oral commissure, dysphagia, dysarthria, and weakness on the left side of the body. She was diagnosed with thrombosis in a segment of the right middle cerebral artery which led to an ischemic area in the right frontal lobe. Termination of pregnancy and conservative treatment was decided, with good resolution of the symptoms.

  11. Perturbations for transient acceleration

    SciTech Connect

    Vargas, Cristofher Zuñiga; Zimdahl, Winfried; Hipólito-Ricaldi, Wiliam S. E-mail: hipolito@ceunes.ufes.br

    2012-04-01

    According to the standard ΛCDM model, the accelerated expansion of the Universe will go on forever. Motivated by recent observational results, we explore the possibility of a finite phase of acceleration which asymptotically approaches another period of decelerated expansion. Extending an earlier study on a corresponding homogeneous and isotropic dynamics, in which interactions between dark matter and dark energy are crucial, the present paper also investigates the dynamics of the matter perturbations both on the Newtonian and General Relativistic (GR) levels and quantifies the potential relevance of perturbations of the dark-energy component. In the background, the model is tested against the Supernova type Ia (SNIa) data of the Constitution set and on the perturbative level against growth rate data, among them those of the WiggleZ survey, and the data of the 2dFGRS project. Our results indicate that a transient phase of accelerated expansion is not excluded by current observations.

  12. Uniform acceleration in general relativity

    NASA Astrophysics Data System (ADS)

    Friedman, Yaakov; Scarr, Tzvi

    2015-10-01

    We extend de la Fuente and Romero's (Gen Relativ Gravit 47:33, 2015) defining equation for uniform acceleration in a general curved spacetime from linear acceleration to the full Lorentz covariant uniform acceleration. In a flat spacetime background, we have explicit solutions. We use generalized Fermi-Walker transport to parallel transport the Frenet basis along the trajectory. In flat spacetime, we obtain velocity and acceleration transformations from a uniformly accelerated system to an inertial system. We obtain the time dilation between accelerated clocks. We apply our acceleration transformations to the motion of a charged particle in a constant electromagnetic field and recover the Lorentz-Abraham-Dirac equation.

  13. Automatic segmentation of cerebral MR images using artificial neural networks

    SciTech Connect

    Alirezaie, J.; Jernigan, M.E.; Nahmias, C.

    1996-12-31

    In this paper we present an unsupervised clustering technique for multispectral segmentation of magnetic resonance (MR) images of the human brain. Our scheme utilizes the Self Organizing Feature Map (SOFM) artificial neural network for feature mapping and generates a set of codebook vectors. By extending the network with an additional layer the map will be classified and each tissue class will be labelled. An algorithm has been developed for extracting the cerebrum from the head scan prior to the segmentation. Extracting the cerebrum is performed by stripping away the skull pixels from the T2 image. Three tissue types of the brain: white matter, gray matter and cerebral spinal fluid (CSF) are segmented accurately. To compare the results with other conventional approaches we applied the c-means algorithm to the problem.

  14. Modeling white matter microstructure

    PubMed Central

    Duval, Tanguy; Stikov, Nikola; Cohen-Adad, Julien

    2016-01-01

    Summary Quantitative magnetic resonance imaging can be combined with advanced biophysical models to measure microstructural features of white matter. Non-invasive microstructural imaging has the potential to revolutionize neuroscience, and acquiring these measures in clinically feasible times would greatly improve patient monitoring and clinical studies of drug efficacy. However, a good understanding of microstructural imaging techniques is essential to set realistic expectations and to prevent over-interpretation of results. This review explains the methodology behind microstructural modeling and imaging, and gives an overview of the breakthroughs and challenges associated with it. PMID:28072382

  15. Snow White Trench (Animation)

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Click on image for animation

    This animation shows the evolution of the trench called 'Snow White' that NASA's Phoenix Mars Lander began digging on the 22nd Martian day of the mission after the May 25, 2008, landing.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  16. Phoenix's Snow White Trench

    NASA Technical Reports Server (NTRS)

    2008-01-01

    A soil sample taken from the informally named 'Snow White' trench at NASA's Phoenix Mars Lander work site produced minerals that indicate evidence of past interaction between the minerals and liquid water.

    This image was taken by the Surface Stereo Imager on Sol 103, the 103rd day since landing (Sept. 8, 2008).

    The trench is approximately 23 centimeters (9 inches) long.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by JPL, Pasadena, Calif. Spacecraft development was by Lockheed Martin Space Systems, Denver.

  17. White Dwarf Calibration

    NASA Astrophysics Data System (ADS)

    Colina, Luis

    1994-01-01

    As a result of last November calibration workshop, all parties agreed that the HST should be switched to the WD basis for absolute fluxes. This proposal implements that decision. A measurement of the absolute sensitivity of the FOS detectors will be performed using theoretical pure hydrogen model atmosphere calculations for three white dwarfs. The high resolution gratings will be used in the 1 arcsec aperture. A four stage peakup of the standard star provides centering in the aperture. Observations are requested for fall 94 with repeated observations about two months after.

  18. Astrocytes and microglia in acute cerebral injury underlying cerebral palsy associated with preterm birth.

    PubMed

    Mallard, Carina; Davidson, Joanne O; Tan, Sidhartha; Green, Colin R; Bennet, Laura; Robertson, Nicola J; Gunn, Alistair Jan

    2014-01-01

    Cerebral palsy is one of the most devastating consequences of brain injury around the time of birth, and nearly a third of cases are now associated with premature birth. Compared with term babies, preterm babies have an increased incidence of complications that may increase the risk of disability, such as intraventricular hemorrhage, periventricular leukomalacia, sepsis, and necrotizing enterocolitis. The response to injury is highly dependent on brain maturity, and although cellular vulnerability is well documented, there is now evidence that premyelinating axons are also particularly sensitive to ischemic injury. In this review, we will explore recent evidence highlighting a central role for glia in mediating increased risk of disability in premature infants, including excessive activation of microglia and opening of astrocytic gap junction hemichannels in spreading injury after brain ischemia, in part likely involving release of adenosine triphosphate (ATP) and overactivation of purinergic receptors, particularly in white matter. We propose the hypothesis that inflammation-induced opening of connexin hemichannels is a key regulating event that initiates a vicious circle of excessive ATP release, which in turn propagates activation of purinergic receptors on microglia and astrocytes. This suggests that developing effective neuroprotective strategies for preterm infants requires a detailed understanding of glial responses.

  19. Microelectromechanical acceleration-sensing apparatus

    DOEpatents

    Lee, Robb M.; Shul, Randy J.; Polosky, Marc A.; Hoke, Darren A.; Vernon, George E.

    2006-12-12

    An acceleration-sensing apparatus is disclosed which includes a moveable shuttle (i.e. a suspended mass) and a latch for capturing and holding the shuttle when an acceleration event is sensed above a predetermined threshold level. The acceleration-sensing apparatus provides a switch closure upon sensing the acceleration event and remains latched in place thereafter. Examples of the acceleration-sensing apparatus are provided which are responsive to an acceleration component in a single direction (i.e. a single-sided device) or to two oppositely-directed acceleration components (i.e. a dual-sided device). A two-stage acceleration-sensing apparatus is also disclosed which can sense two acceleration events separated in time. The acceleration-sensing apparatus of the present invention has applications, for example, in an automotive airbag deployment system.

  20. [Cerebral hydatid disease: imaging features].

    PubMed

    Tlili-Graiess, K; El-Ouni, F; Gharbi-Jemni, H; Arifa, N; Moulahi, H; Mrad-Dali, K; Guesmi, H; Abroug, S; Yacoub, M; Krifa, H

    2006-12-01

    Cerebral hytatid cysts (HC) are extremely rare, forming 2% of all intra cranial space occupying lesions even in counties where the disease is endemic. HC diagnosis is usually based on a pathognomonic computed tomography (CT) pattern. In order to assess the value of MR we reviewed the CT (n=25) and magnetic resonance (MR, n=4 including diffusion and proton magnetic resonance spectroscopy in 1) imaging of 25 patients with pathologically confirmed cerebral hydatid disease. 19 HC were seen in children under 16 years. All were supra tentorial with 22 in the middle cerebral artery territory. HC was solitary in 18 cases, unilocular in 23 and multi-vesicular in 2 with heavily calcified pericyst in 1. 2 cysts were intra ventricular and 1 intra aqueducal. The most typical features were well defined, smooth thin walled spherical or oval cystic lesions of CSF density and/or signal with considerable mass effect (20/25). Surrounding oedema with complete or incomplete rim enhancement was seen in 3 cases which were labelled as complicated and/or infected cysts. Although CT is diagnostic of hydatid disease in almost all cases (22/25), MRI including diffusion and spectroscopy precisely demonstrate location, number, cyst capsule, type of signal and enhancement and allows diagnosis of atypical or complicated HC and appears more helpful in surgical planning.

  1. Bone age in cerebral palsy

    PubMed Central

    Miranda, Eduardo Régis de Alencar Bona; Palmieri, Maurício D'arc; de Assumpção, Rodrigo Montezuma César; Yamada, Helder Henzo; Rancan, Daniela Regina; Fucs, Patrícia Maria de Moraes Barros

    2013-01-01

    Objective To compare the chronological age and bone age among cerebral palsy patients in the outpatient clinic and its correlation with the type of neurological involvement, gender and functional status. Methods 401 patients with spastic cerebral palsy, and ages ranging from three months to 20 years old, submitted to radiological examination for bone age and analyzed by two independent observers according Greulich & Pyle. Results In the topographic distribution, there was a significant delay (p<0.005) in tetraparetic (17.7 months), hemiparetic (10.1 months), and diparetic patients (7.9 months). In the hemiparetic group, the mean bone age in the affected side was 96.88 months and the uncompromised side was 101.13 months (p<0.005). Regarding functional status, the ambulatory group showed a delay of 18.73 months in bone age (p<0.005). Comparing bone age between genders, it was observed a greater delay in males (13.59 months) than in females (9.63 months), but not statistically significant (p = 0.54). Conclusion There is a delay in bone age compared to chronological age influenced by the topography of spasticity, functional level and gender in patients with cerebral palsy. Level of Evidence IV, Case Series. PMID:24453693

  2. Cerebral ischaemia: A neuroradiological study

    SciTech Connect

    Bories, J.

    1985-01-01

    After a brief clinical and pathophysiological approach, the papers presented in this book are devoted to CT and angiography. Concerning CT, a particular study has been made of cerebral arterial territories on cuts parallel to the orbito-meatal line: these are very important in making the differential diagnosis from some tumors. Also concerning CT, a paper has been devoted to cerebral ''lacunae.'' The term ''lacuna'' as far as CT imaging is concerned, should be reserved only for those hypodense areas corresponding to small cavities containing fluid, which are sequelae of infarcts in the territory of penetrating arteries. Before this sequellar state come all the evolutive states of a small deep infarct. The angiographic study specifies the indications of angiography in the study of cerebral ischemia, and the techniques to be used. It shows the main etiologic aspects. Because of the important place of vascular surgery today, it seemed necessary to show also the main post operative angiographic aspects. After CT and angiography, some pages are reserved to more modern techniques. Finally, some pages are devoted to certain particular associations and etiologies: childhood, cardiopathies, migraine, oral contraception and end with venous infarction.

  3. Diffusive Shock Acceleration

    NASA Astrophysics Data System (ADS)

    Baring, Matthew

    2003-04-01

    The process of diffusive acceleration of charged particles in shocked plasmas is widely invoked in astrophysics to account for the ubiquitous presence of signatures of non-thermal relativistic electrons and ions in the universe. This statistical energization mechanism, manifested in turbulent media, was first posited by Enrico Fermi in 1949 to explain the observed cosmic ray population, which exhibits an almost power-law distribution in rigidity. The absence of a momentum scale is a key characteristic of diffusive shock acceleration, and astrophysical systems generally only impose scales at the injection (low energy) and loss (high energy) ends of the particle spectrum. The existence of structure in the cosmic ray spectrum (the "knee") at around 3000 TeV has promoted contentions that there are at least two origins for cosmic rays, a galactic one supplying those up to the knee, and perhaps an extragalactic one that can explain even the ultra-high energy cosmic rays (UHECRs) seen at 1-300 EeV. Accounting for the UHECRs with familiar astrophysical sites of acceleration has historically proven difficult due to the need to assume high magnetic fields in order to reduce the shortest diffusive acceleration timescale, the ion gyroperiod, to meaningful values. Yet active galaxies and gamma-ray bursts remain strong and interesting candidate sources for UHECRs, turning the theoretical focus to relativistic shocks. This review summarizes properties of diffusive shock acceleration that are salient to the issue of UHECR generation. These include spectral indices, anisotropies, acceleration efficencies and timescales, as functions of the shock speed and mean field orientation, and also the degree of field turbulence. Astrophysical sites for UHECR production are also critiqued.

  4. 'Light Sail' Acceleration Reexamined

    SciTech Connect

    Macchi, Andrea; Veghini, Silvia; Pegoraro, Francesco

    2009-08-21

    The dynamics of the acceleration of ultrathin foil targets by the radiation pressure of superintense, circularly polarized laser pulses is investigated by analytical modeling and particle-in-cell simulations. By addressing self-induced transparency and charge separation effects, it is shown that for 'optimal' values of the foil thickness only a thin layer at the rear side is accelerated by radiation pressure. The simple 'light sail' model gives a good estimate of the energy per nucleon, but overestimates the conversion efficiency of laser energy into monoenergetic ions.

  5. HIGH GRADIENT INDUCTION ACCELERATOR

    SciTech Connect

    Caporaso, G J; Sampayan, S; Chen, Y; Blackfield, D; Harris, J; Hawkins, S; Holmes, C; Krogh, M; Nelson, S; Nunnally, W; Paul, A; Poole, B; Rhodes, M; Sanders, D; Selenes, K; Sullivan, J; Wang, L; Watson, J

    2007-06-21

    A new type of compact induction accelerator is under development at the Lawrence Livermore National Laboratory that promises to increase the average accelerating gradient by at least an order of magnitude over that of existing induction machines. The machine is based on the use of high gradient vacuum insulators, advanced dielectric materials and switches and is stimulated by the desire for compact flash x-ray radiography sources. Research describing an extreme variant of this technology aimed at proton therapy for cancer will be described. Progress in applying this technology to several applications will be reviewed.

  6. "Light sail" acceleration reexamined.

    PubMed

    Macchi, Andrea; Veghini, Silvia; Pegoraro, Francesco

    2009-08-21

    The dynamics of the acceleration of ultrathin foil targets by the radiation pressure of superintense, circularly polarized laser pulses is investigated by analytical modeling and particle-in-cell simulations. By addressing self-induced transparency and charge separation effects, it is shown that for "optimal" values of the foil thickness only a thin layer at the rear side is accelerated by radiation pressure. The simple "light sail" model gives a good estimate of the energy per nucleon, but overestimates the conversion efficiency of laser energy into monoenergetic ions.

  7. High intensity hadron accelerators

    SciTech Connect

    Teng, L.C.

    1989-05-01

    This rapporteur report consists mainly of two parts. Part I is an abridged review of the status of all High Intensity Hadron Accelerator projects in the world in semi-tabulated form for quick reference and comparison. Part II is a brief discussion of the salient features of the different technologies involved. The discussion is based mainly on my personal experiences and opinions, tempered, I hope, by the discussions I participated in in the various parallel sessions of the workshop. In addition, appended at the end is my evaluation and expression of the merits of high intensity hadron accelerators as research facilities for nuclear and particle physics.

  8. Ambulatory arterial stiffness index is not associated with magnetic resonance imaging markers of cerebral small vessel disease in lacunar stroke patients.

    PubMed

    Klarenbeek, Pim; van Oostenbrugge, Robert J; Staals, Julie

    2015-05-01

    Ambulatory arterial stiffness index (AASI) is associated with microvascular damage in other organs, but the association with microvascular brain damage is unknown. The association of AASI with magnetic resonance imaging (MRI) markers of cerebral small vessel disease in 143 patients with lacunar stroke was investigated. We performed 24-hour ambulatory blood pressure monitoring and scored the presence of lacunes, white matter hyperintensities, perivascular spaces, and cerebral microbleeds on brain MRI. In logistic regression analyses, AASI was associated with white matter hyperintensities, but, after adjustment for age and sex, this association lost significance. AASI was not associated with lacunes, microbleeds, or perivascular spaces. Systolic and diastolic 24-hour blood pressure values were associated with lacunes, perivascular spaces, and microbleeds independent of age and sex. Despite its significance and growing interest as a possible prognostic and therapeutic target in (micro)vascular diseases, AASI seems to have no added value over standard 24-hour blood pressure in cerebral small vessel disease.

  9. Cerebral embolic stroke after disappearing takotsubo cardiomyopathy.

    PubMed

    Matsuzono, Kosuke; Ikeda, Yoshio; Deguchi, Shoko; Yamashita, Toru; Kurata, Tomoko; Deguchi, Kentaro; Abe, Koji

    2013-11-01

    Takotsubo cardiomyopathy can induce cerebral embolic stroke because of intracardiac thrombosis, but the timing of cardiogenic embolism relating to takotsubo cardiomyopathy has not been well described. We evaluated a 71-year-old woman with takotsubo cardiomyopathy, who developed cardiogenic cerebral embolism after recovery of cardiac wall motion. Nevertheless, we treated her with anticoagulation therapy. The present clinical observation suggests that attention should be paid to the timing when takotsubo cardiomyopathy resolves against risk of cardiogenic cerebral embolism.

  10. Cerebral toxoplasmosis in a patient with acquired immunodeficiency syndrome.

    PubMed

    Naqi, Rohana; Azeemuddin, Muhammad; Ahsan, Humera

    2010-04-01

    Cerebral toxoplasmosis commonly affects patients with advanced HIV immunodeficiency. Toxoplasmosis in patients who are immunocompromised can be severe and debilitating in patients with Central Nervous System (CNS) involvement and the condition may be fatal. We report the case of a 40-year-old man who was a known case of HIV and presented with cerebral toxoplasmosis. His Magnetic Resonance Imaging (MRI) scan showed multiple ring enhancing lesions with extensive surrounding oedema in supratentorial as well as infratentorial region. Lesions were mainly located in the periventricular region as well as at the grey-white matter junction and showed enhancement in the periphery as well as a tiny nodular enhancement in the centre. Patient was started on Septran DS, empirically for toxoplasmosis and steroids to reduce intracranial pressure. On follow up MRI scan after 10 days there was a reduction in size, number and enhancement of the masses with decrease in the surrounding oedema. Patient was clinically stable, oriented and his fever settled. He was discharged from hospital on same medication and advised to continue regular follow-up.

  11. Structural network connectivity and cognition in cerebral small vessel disease.

    PubMed

    Tuladhar, Anil M; van Dijk, Ewoud; Zwiers, Marcel P; van Norden, Anouk G W; de Laat, Karlijn F; Shumskaya, Elena; Norris, David G; de Leeuw, Frank-Erik

    2016-01-01

    Cerebral small vessel disease (SVD), including white matter hyperintensities (WMH), lacunes and microbleeds, and brain atrophy, are related to cognitive impairment. However, these magnetic resonance imaging (MRI) markers for SVD do not account for all the clinical variances observed in subjects with SVD. Here, we investigated the relation between conventional MRI markers for SVD, network efficiency and cognitive performance in 436 nondemented elderly with cerebral SVD. We computed a weighted structural connectivity network from the diffusion tensor imaging and deterministic streamlining. We found that SVD-severity (indicated by higher WMH load, number of lacunes and microbleeds, and lower total brain volume) was related to networks with lower density, connection strengths, and network efficiency, and to lower scores on cognitive performance. In multiple regressions models, network efficiency remained significantly associated with cognitive index and psychomotor speed, independent of MRI markers for SVD and mediated the associations between these markers and cognition. This study provides evidence that network (in)efficiency might drive the association between SVD and cognitive performance. This highlights the importance of network analysis in our understanding of SVD-related cognitive impairment in addition to conventional MRI markers for SVD and might provide an useful tool as disease marker.

  12. Quantitative nuclear magnetic resonance imaging: characterisation of experimental cerebral oedema.

    PubMed Central

    Barnes, D; McDonald, W I; Johnson, G; Tofts, P S; Landon, D N

    1987-01-01

    Magnetic resonance imaging (MRI) has been used quantitatively to define the characteristics of two different models of experimental cerebral oedema in cats: vasogenic oedema produced by cortical freezing and cytotoxic oedema induced by triethyl tin. The MRI results have been correlated with the ultrastructural changes. The images accurately delineated the anatomical extent of the oedema in the two lesions, but did not otherwise discriminate between them. The patterns of measured increase in T1' and T2' were, however, characteristic for each type of oedema, and reflected the protein content. The magnetisation decay characteristics of both normal and oedematous white matter were monoexponential for T1 but biexponential for T2 decay. The relative sizes of the two component exponentials of the latter corresponded with the physical sizes of the major tissue water compartments. Quantitative MRI data can provide reliable information about the physico-chemical environment of tissue water in normal and oedematous cerebral tissue, and are useful for distinguishing between acute and chronic lesions in multiple sclerosis. Images PMID:3572428

  13. Prevention and Management of Cerebral Small Vessel Disease

    PubMed Central

    Mok, Vincent

    2015-01-01

    Lacunar infarcts/lacunes, white matter hyperintensities (WMH), and cerebral microbleeds (CMBs) are considered various manifestations of cerebral small vessel disease (SVD). Since the exact mechanisms of these manifestations differ, their associated risk factors differ. High blood pressure is the most consistent risk factor for all of these manifestations. However, a "J curve" phenomenon in terms of blood pressure probably exists for WMH. The association between cholesterol levels and lacunar infarcts/lacunes or WMH was less consistent and sometimes conflicting; a low cholesterol level probably increases the risk of CMBs. Homocysteinemia appears to be associated with WMH. It is noteworthy that the risk factors profile may also differ between different lacunar patterns and CMBs located at different parts of the brain. Thrombolysis, antihypertensives, and statins are used to treat patients with symptomatic lacunar infarction, just as in those with other stroke subtypes. However, it should be remembered that bleeding risks increase in patients with extensive WMH and CMBs after thrombolysis therapy. According to the Secondary Prevention of Small Subcortical Strokes trial results, a blood pressure reduction to <130 mmHg is recommended in patients with symptomatic lacunar infarction. However, an excessive blood pressure decrease may induce cognitive decline in older patients with extensive WMH. Dual antiplatelet therapy (aspirin plus clopidogrel) should be avoided because of the excessive risk of intracerebral hemorrhage. Although no particular antiplatelet is recommended, drugs such as cilostazol or triflusal may have advantages for patients with SVD since they are associated with less frequent bleeding complications than aspirin. PMID:26060798

  14. Cerebral Palsy. Fact Sheet = La Paralisis Cerebral. Hojas Informativas Sobre Discapacidades.

    ERIC Educational Resources Information Center

    National Information Center for Children and Youth with Disabilities, Washington, DC.

    This fact sheet on cerebral palsy is written in both English and Spanish. First, it provides a definition of cerebral palsy and considers various causes (e.g., an insufficient amount of oxygen reaching the fetal or newborn brain). The fact sheet then offers incidence figures and explains characteristics of the three main types of cerebral palsy:…

  15. Cerebral Palsy Checklist: Teens & Young Adult (13 to 21)

    MedlinePlus

    ... 2-Year-Old Cerebral Palsy Checklist: Teens & Young Adults KidsHealth > For Parents > Cerebral Palsy Checklist: Teens & Young ... plan healthy meals. continue Step 3: Explore Young-Adult Education Young adults with cerebral palsy are entitled ...

  16. Acute cerebral vascular accident associated with hyperperfusion.

    PubMed

    Soin, J S; Burdine, J A

    1976-01-01

    Cerebral radionuclide angiography can demonstrate decreased or normal radioactivity in the affected region during the arterial phase in patients who have sustained a cerebral vascular accident and thus enhances the diagnostic specificity of the static brain image. In an occasional patient, however, a seemingly paradoxical pattern of regional hyperperfusion with a return to normal or subnormal perfusion following the acute phase has been observed. This phenomenon, called "luxury perfusion," has been defined using intra-arterial 133Xe for semiquantitative cerebral blood flow measurements and should be kept in mind as a potentially misleading cerebral imaging pattern.

  17. Genetics Home Reference: hereditary cerebral amyloid angiopathy

    MedlinePlus

    ... Testing Registry: Dementia, familial Danish Genetic Testing Registry: Hereditary cerebral amyloid angiopathy, Icelandic type Other Diagnosis and Management Resources (2 links) Johns Hopkins Medicine: ...

  18. Vulnerability of premyelinating oligodendrocytes to white-matter damage in neonatal brain injury.

    PubMed

    Liu, Xiao-Bo; Shen, Yan; Plane, Jennifer M; Deng, Wenbin

    2013-04-01

    Premature birth is a significant economic and public health burden, and its incidence is rising. Periventricular leukomalacia (PVL) is the predominant form of brain injury in premature infants and the leading cause of cerebral palsy. PVL is characterized by selective white-matter damage with prominent oligodendroglial injury. The maturation-dependent vulnerability of developing and premyelinating oligodendrocytes to excitotoxic, oxidative, and inflammatory forms of injury is a major factor in the pathogenesis of PVL. Recent studies using mouse models of PVL reveal that synapses between axons and developing oligodendrocytes are quickly and profoundly damaged in immature white matter. Axon-glia synapses are highly vulnerable to white-matter injury in the developing brain, and the loss of synapses between axons and premyelinating oligodendrocytes occurs before any cellular loss in the immature white matter. Microglial activation and astrogliosis play important roles in triggering white-matter injury. Impairment of white-matter development and function in the neonatal period contributes critically to functional and behavioral deficits. Preservation of the integrity of the white matter is likely key in the treatment of PVL and subsequent neurological consequences and disabilities.

  19. CORRELATION OF HARD X-RAY AND WHITE LIGHT EMISSION IN SOLAR FLARES

    SciTech Connect

    Kuhar, Matej; Krucker, Säm; Battaglia, Marina; Kleint, Lucia; Casadei, Diego; Oliveros, Juan Carlos Martinez; Hudson, Hugh S.

    2016-01-01

    A statistical study of the correlation between hard X-ray and white light emission in solar flares is performed in order to search for a link between flare-accelerated electrons and white light formation. We analyze 43 flares spanning GOES classes M and X using observations from the Reuven Ramaty High Energy Solar Spectroscopic Imager and Helioseismic and Magnetic Imager. We calculate X-ray fluxes at 30 keV and white light fluxes at 6173 Å summed over the hard X-ray flare ribbons with an integration time of 45 s around the peak hard-X ray time. We find a good correlation between hard X-ray fluxes and excess white light fluxes, with a highest correlation coefficient of 0.68 for photons with energy of 30 keV. Assuming the thick target model, a similar correlation is found between the deposited power by flare-accelerated electrons and the white light fluxes. The correlation coefficient is found to be largest for energy deposition by electrons above ∼50 keV. At higher electron energies the correlation decreases gradually while a rapid decrease is seen if the energy provided by low-energy electrons is added. This suggests that flare-accelerated electrons of energy ∼50 keV are the main source for white light production.

  20. Correlation of Hard X-Ray and White Light Emission in Solar Flares

    NASA Astrophysics Data System (ADS)

    Kuhar, Matej; Krucker, Säm; Martínez Oliveros, Juan Carlos; Battaglia, Marina; Kleint, Lucia; Casadei, Diego; Hudson, Hugh S.

    2016-01-01

    A statistical study of the correlation between hard X-ray and white light emission in solar flares is performed in order to search for a link between flare-accelerated electrons and white light formation. We analyze 43 flares spanning GOES classes M and X using observations from the Reuven Ramaty High Energy Solar Spectroscopic Imager and Helioseismic and Magnetic Imager. We calculate X-ray fluxes at 30 keV and white light fluxes at 6173 Å summed over the hard X-ray flare ribbons with an integration time of 45 s around the peak hard-X ray time. We find a good correlation between hard X-ray fluxes and excess white light fluxes, with a highest correlation coefficient of 0.68 for photons with energy of 30 keV. Assuming the thick target model, a similar correlation is found between the deposited power by flare-accelerated electrons and the white light fluxes. The correlation coefficient is found to be largest for energy deposition by electrons above ∼50 keV. At higher electron energies the correlation decreases gradually while a rapid decrease is seen if the energy provided by low-energy electrons is added. This suggests that flare-accelerated electrons of energy ∼50 keV are the main source for white light production.

  1. Radioisotope Dating with Accelerators.

    ERIC Educational Resources Information Center

    Muller, Richard A.

    1979-01-01

    Explains a new method of detecting radioactive isotopes by counting their accelerated ions rather than the atoms that decay during the counting period. This method increases the sensitivity by several orders of magnitude, and allows one to find the ages of much older and smaller samples. (GA)

  2. Accelerated Management Development

    ERIC Educational Resources Information Center

    Munn, Kenn

    1974-01-01

    Western Electric's accelerated management development program for hand picked college graduate students consists of a high risk training project in which the management candidate accomplishes his task or is terminated. The success of such projects puts candidates in third level management in seven years or half the normal time. (DS)

  3. FPGA Verification Accelerator (FVAX)

    NASA Technical Reports Server (NTRS)

    Oh, Jane; Burke, Gary

    2008-01-01

    Is Verification Acceleration Possible? - Increasing the visibility of the internal nodes of the FPGA results in much faster debug time - Forcing internal signals directly allows a problem condition to be setup very quickly center dot Is this all? - No, this is part of a comprehensive effort to improve the JPL FPGA design and V&V process.

  4. Role of impaired CO2 reactivity in the diagnosis of cerebral low flow infarcts.

    PubMed Central

    Baumgartner, R W; Regard, M

    1994-01-01

    Previous studies on CO2 reactivity in cerebral low flow infarcts (LFIs) included patients with lesions in the frontoparasagittal area, supraganglionic white matter, and temporoparieto-occipital zone. Supraganglionic white matter LFIs are, however, difficult to separate from non-low flow induced infarcts of the lacunar type, and temporoparieto-occipital LFIs from infarcts in the territory of the inferior stem of the middle cerebral artery. The CO2 reactivity of the middle cerebral artery was studied in 56 patients with high grade stenoses and occlusions of the internal carotid artery and LFIs (n = 9) in the frontoparasagittal border zone, territorial infarcts (n = 26), no infarcts (n = 21), and normal subjects (n = 25) by means of transcranial Doppler sonography. The aim was to investigate whether patients with LFIs have significantly lower CO2 reactivity than patients with territorial infarcts, no infarcts, and normal subjects. Patients with LFIs had the most severely reduced CO2 reactivity on the symptomatic side and CO2 reactivity was significantly lower than on the asymptomatic side. It was also lower than in patients with unilateral and bilateral internal carotid artery obstructions and territorial infarcts, asymptomatic patients, and healthy volunteers. It is concluded that LFIs are associated with significantly reduced CO2 reactivity. PMID:8021667

  5. Combined generating-accelerating buncher for compact linear accelerators

    NASA Astrophysics Data System (ADS)

    Savin, E. A.; Matsievskiy, S. V.; Sobenin, N. P.; Sokolov, I. D.; Zavadtsev, A. A.

    2016-09-01

    Described in the previous article [1] method of the power extraction from the modulated electron beam has been applied to the compact standing wave electron linear accelerator feeding system, which doesnt require any connection waveguides between the power source and the accelerator itself [2]. Generating and accelerating bunches meet in the hybrid accelerating cell operating at TM020 mode, thus the accelerating module is placed on the axis of the generating module, which consists from the pulsed high voltage electron sources and electrons dumps. This combination makes the accelerator very compact in size which is very valuable for the modern applications such as portable inspection sources. Simulations and geometry cold tests are presented.

  6. Real-time Optical Network for Accelerator Control

    SciTech Connect

    Lee, Keun

    2012-06-27

    The timing requirements of a modern accelerator complex call for several features. The first is a system for high precision relative timing among accelerator components. Stabilized fiber links have already been demonstrated to achieve sub-10 femtoseconds relative timing precision. The second is a system for timing distribution of absolute time with sufficient precision to identify a specific RF bucket. The White Rabbit technology is a promising candidate to deliver the absolute time that is linked to the GPS clock. In this study we demonstrated that these two technologies can be combined in a way that the absolute time information can be delivered to the stabilized fiber link system. This was accomplished by researching the design of the stabilized fiber and White Rabbit systems and devising adaptation modules that facilitate co-existence of both systems in the same FPGA environment. We built a prototype system using off-the-shelf products and implemented a proof-of-concept version of the FPGA firmware. The test verified that the White Rabbit features operate correctly under the stabilized fiber system environment. This work demonstrates that turn-key femtosecond timing systems with absolute time information can be built cost effectively and deployed in various accelerator environments. This will lead to many new applications in chemistry, biology and surface dynamics, to name a few.

  7. Neurodegeneration in accelerated aging.

    PubMed

    Scheibye-Knudsen, Moren

    2016-11-01

    The growing proportion of elderly people represents an increasing economic burden, not least because of age-associated diseases that pose a significant cost to the health service. Finding possible interventions to age-associated disorders therefore have wide ranging implications. A number of genetically defined accelerated aging diseases have been characterized that can aid in our understanding of aging. Interestingly, all these diseases are associated with defects in the maintenance of our genome. A subset of these disorders, Cockayne syndrome, Xeroderma pigmentosum group A and ataxia-telangiectasia, show neurological involvement reminiscent of what is seen in primary human mitochondrial diseases. Mitochondria are the power plants of the cells converting energy stored in oxygen, sugar, fat, and protein into ATP, the energetic currency of our body. Emerging evidence has linked this organelle to aging and finding mitochondrial dysfunction in accelerated aging disorders thereby strengthens the mitochondrial theory of aging. This theory states that an accumulation of damage to the mitochondria may underlie the process of aging. Indeed, it appears that some accelerated aging disorders that show neurodegeneration also have mitochondrial dysfunction. The mitochondrial alterations may be secondary to defects in nuclear DNA repair. Indeed, nuclear DNA damage may lead to increased energy consumption, alterations in mitochondrial ATP production and defects in mitochondrial recycling, a term called mitophagy. These changes may be caused by activation of poly-ADP-ribose-polymerase 1 (PARP1), an enzyme that responds to DNA damage. Upon activation PARP1 utilizes key metabolites that attenuate pathways that are normally protective for the cell. Notably, pharmacological inhibition of PARP1 or reconstitution of the metabolites rescues the changes caused by PARP1 hyperactivation and in many cases reverse the phenotypes associated with accelerated aging. This implies that modulation

  8. Menopause accelerates biological aging

    PubMed Central

    Levine, Morgan E.; Lu, Ake T.; Chen, Brian H.; Hernandez, Dena G.; Singleton, Andrew B.; Ferrucci, Luigi; Bandinelli, Stefania; Salfati, Elias; Manson, JoAnn E.; Quach, Austin; Kusters, Cynthia D. J.; Kuh, Diana; Wong, Andrew; Teschendorff, Andrew E.; Widschwendter, Martin; Ritz, Beate R.; Absher, Devin; Assimes, Themistocles L.; Horvath, Steve

    2016-01-01

    Although epigenetic processes have been linked to aging and disease in other systems, it is not yet known whether they relate to reproductive aging. Recently, we developed a highly accurate epigenetic biomarker of age (known as the “epigenetic clock”), which is based on DNA methylation levels. Here we carry out an epigenetic clock analysis of blood, saliva, and buccal epithelium using data from four large studies: the Women's Health Initiative (n = 1,864); Invecchiare nel Chianti (n = 200); Parkinson's disease, Environment, and Genes (n = 256); and the United Kingdom Medical Research Council National Survey of Health and Development (n = 790). We find that increased epigenetic age acceleration in blood is significantly associated with earlier menopause (P = 0.00091), bilateral oophorectomy (P = 0.0018), and a longer time since menopause (P = 0.017). Conversely, epigenetic age acceleration in buccal epithelium and saliva do not relate to age at menopause; however, a higher epigenetic age in saliva is exhibited in women who undergo bilateral oophorectomy (P = 0.0079), while a lower epigenetic age in buccal epithelium was found for women who underwent menopausal hormone therapy (P = 0.00078). Using genetic data, we find evidence of coheritability between age at menopause and epigenetic age acceleration in blood. Using Mendelian randomization analysis, we find that two SNPs that are highly associated with age at menopause exhibit a significant association with epigenetic age acceleration. Overall, our Mendelian randomization approach and other lines of evidence suggest that menopause accelerates epigenetic aging of blood, but mechanistic studies will be needed to dissect cause-and-effect relationships further. PMID:27457926

  9. Chemokines in cerebrospinal fluid correlate with cerebral metabolite patterns in HIV-infected individuals.

    PubMed

    Letendre, Scott L; Zheng, Jialin C; Kaul, Marcus; Yiannoutsos, Constantin T; Ellis, Ronald J; Taylor, Michael J; Marquie-Beck, Jennifer; Navia, Bradford

    2011-02-01

    Chemokines influence HIV neuropathogenesis by affecting the HIV life cycle, trafficking of macrophages into the nervous system, glial activation, and neuronal signaling and repair processes; however, knowledge of their relationship to in vivo measures of cerebral injury is limited. The primary objective of this study was to determine the relationship between a panel of chemokines in cerebrospinal fluid (CSF) and cerebral metabolites measured by proton magnetic resonance spectroscopy (MRS) in a cohort of HIV-infected individuals. One hundred seventy-one stored CSF specimens were assayed from HIV-infected individuals who were enrolled in two ACTG studies that evaluated the relationship between neuropsychological performance and cerebral metabolites. Concentrations of six chemokines (fractalkine, IL-8, IP-10, MCP-1, MIP-1β, and SDF-1) were measured and compared with cerebral metabolites individually and as composite neuronal, basal ganglia, and inflammatory patterns. IP-10 and MCP-1 were the chemokines most strongly associated with individual cerebral metabolites. Specifically, (1) higher IP-10 levels correlated with lower N-acetyl aspartate (NAA)/creatine (Cr) ratios in the frontal white matter and higher MI/Cr ratios in all three brain regions considered and (2) higher MCP-1 levels correlated with lower NAA/Cr ratios in frontal white matter and the parietal cortex. IP-10, MCP-1, and IL-8 had the strongest associations with patterns of cerebral metabolites. In particular, higher levels of IP-10 correlated with lower neuronal pattern scores and higher basal ganglia and inflammatory pattern scores, the same pattern which has been associated with HIV-associated neurocognitive disorders (HAND). Subgroup analysis indicated that the effects of IP-10 and IL-8 were influenced by effective antiretroviral therapy and that memantine treatment may mitigate the neuronal effects of IP-10. This study supports the role of chemokines in HAND and the validity of MRS as an assessment

  10. White Oak Dam stability analysis. Volume I

    SciTech Connect

    Ahmed, S.B.

    1994-01-01

    A parametric study was conducted to evaluate the stability of the White Oak Dam (WOD) embankment and foundation. Slope stability analyses were performed for the upper and lower bound soil properties at three sections of the dam using the PCSTABL4 computer program. Minimum safety factors were calculated for the applicable seismic and static loading conditions. Liquefaction potential of the dam embankment and foundation solid during the seismic event was assessed by using simplified procedures. The WOD is classified as a low hazard facility and the Evaluation Basis Earthquake (EBE) is defined as an earthquake with a magnitude of m{sub b} = 5.6 and a Peak Ground Accelerator (PGA) of 0.13 g. This event is approximately equivalent to a Modified Mercalli Intensity of VI-VIII. The EBE is used to perform the seismic evaluation for slope stability and liquefaction potential. Results of the stability analyses and the liquefaction assessment lead to the conclusion that the White Oak Dam is safe and stable for the static and the seismic events defined in this study. Ogden Environmental, at the request of MMES, has checked and verified the calculations for the critical loading conditions and performed a peer review of this report. Ogden has determined that the WOD is stable under the defined static and seismic loading conditions and the embankment materials are in general not susceptible to liquefaction.

  11. Multiple Pathways to Whiteness: White Teachers' Unsteady Racial Identities

    ERIC Educational Resources Information Center

    Miller, Erin T.

    2017-01-01

    Teacher education programs in the US, recognizing the mismatch that exists in preschool provision between mostly white teachers and a very diverse intake of young children, have begun to explore ways of raising racial awareness among pre-service teachers, with the aim of improving non-white children's classroom experiences and outcomes. This paper…

  12. Breakin' down Whiteness in Antiracist Teaching: Introducing Critical Whiteness Pedagogy

    ERIC Educational Resources Information Center

    Matias, Cheryl E.; Mackey, Janiece

    2016-01-01

    Because of the changing nature of race the role of antiracist teaching is a forever-evolving process. Acknowledging that the majority of the U.S. teaching force, from K-12 to teacher education in institutions of higher education, are white middle-class females, it becomes imperative to unveil pedagogical applications of critical whiteness studies.…

  13. The Achievement Gap between White and Non-White Students

    ERIC Educational Resources Information Center

    Rojas-LeBouef, Ana; Slate, John R.

    2012-01-01

    This Collection contains three seminal modules by Authors Ana Rojas-LeBouef and John R. Slate, professors and researchers from Sam Houston State University in Texas. They are nationally recognized scholars in the area of the academic inequity between White and Non-White students. This paper is divided into three chapters. Chapter 1--The…

  14. One Black, One White: Power, White Privilege, & Creating Safe Spaces

    ERIC Educational Resources Information Center

    Delano-Oriaran, Omobolade O.; Parks, Marguerite W.

    2015-01-01

    This article explores the experiences of two professors as they teach about White privilege in predominately White institutions of higher education. The authors discuss how racial potentiality shapes the classroom climates of each of the professors and then present strategies that utilize safe spaces to navigate students away from the resistance…

  15. White Religious Educators Resisting White Fragility: Lessons from Mystics

    ERIC Educational Resources Information Center

    Hess, Mary E.

    2017-01-01

    Decades of work in dismantling racism have not yielded the kind of results for which religious educators have hoped. One primary reason has been what scholars term "white fragility," a symptom of the structural racism which confers systemic privilege upon White people. Lessons learned from Christian mystics point to powerful ways to…

  16. Cerebral vascular findings in PAPA syndrome: cerebral arterial vasculopathy or vasculitis and a posterior cerebral artery dissecting aneurysm.

    PubMed

    Khatibi, Kasra; Heit, Jeremy J; Telischak, Nicholas A; Elbers, Jorina M; Do, Huy M

    2015-06-24

    A young patient with PAPA (pyogenic arthritis, pyoderma gangrenosum, and acne) syndrome developed an unusual cerebral arterial vasculopathy/vasculitis (CAV) that resulted in subarachnoid hemorrhage from a ruptured dissecting posterior cerebral artery (PCA) aneurysm. This aneurysm was successfully treated by endovascular coil sacrifice of the affected segment of the PCA. The patient made an excellent recovery with no significant residual neurologic deficit.

  17. Cerebral vascular findings in PAPA syndrome: cerebral arterial vasculopathy or vasculitis and a posterior cerebral artery dissecting aneurysm.

    PubMed

    Khatibi, Kasra; Heit, Jeremy J; Telischak, Nicholas A; Elbers, Jorina M; Do, Huy M

    2016-08-01

    A young patient with PAPA (pyogenic arthritis, pyoderma gangrenosum, and acne) syndrome developed an unusual cerebral arterial vasculopathy/vasculitis (CAV) that resulted in subarachnoid hemorrhage from a ruptured dissecting posterior cerebral artery (PCA) aneurysm. This aneurysm was successfully treated by endovascular coil sacrifice of the affected segment of the PCA. The patient made an excellent recovery with no significant residual neurologic deficit.

  18. Radiosurgery for brain metastases and cerebral edema.

    PubMed

    Gazit, Inbal; Har-Nof, Sagi; Cohen, Zvi R; Zibly, Zion; Nissim, Uzi; Spiegelmann, Roberto

    2015-03-01

    The objective of this study was to assess reduction in cerebral edema following linear accelerator radiosurgery (LINAC) as first line therapy for brain metastasis. We reviewed the medical records of all patients who underwent LINAC radiosurgery for brain metastasis at our institution during 2010-2012, and who had not previously undergone either surgery or whole brain radiotherapy. Data were analyzed for 55 brain metastases from 46 patients (24 males), mean age 59.9 years. During the 2 months following LINAC radiosurgery, the mean steroid dose decreased from 4.8 to 2.6 mg/day, the mean metastasis volume decreased from 3.79±4.12 cc to 2.8±4.48 cc (p=0.001), and the mean edema volume decreased from 16.91±30.15 cc to 12.85±24.47 cc (p=0.23). The 17 patients with reductions of more than 50% in brain edema volume had single metastases. Edema volume in the nine patients with two brain metastases remained stable in five patients (volume change <10%, 0-2 cc) and increased in four patients (by >10%, 2-14 cc). In a subanalysis of eight metastases with baseline edema volume greater than 40 cc, edema volume decreased from 77.27±37.21 cc to 24.84±35.6 cc (p=0.034). Reductions in brain edema were greater in metastases for which non-small-cell lung carcinoma and breast cancers were the primary diseases. Overall, symptoms improved in most patients. No patients who were without symptoms or who had no signs of increased intracranial pressure at baseline developed signs of intracranial pressure following LINAC radiosurgery. In this series, LINAC stereotactic radiosurgery for metastatic brain lesions resulted in early reduction in brain edema volume in single metastasis patients and those with large edema volumes, and reduced the need for steroids.

  19. Regional cerebral oxygen saturation guided cerebral protection in a parturient with Takayasu's arteritis undergoing cesarean section: a case report.

    PubMed

    Xiao, Wei; Wang, Tianlong; Fu, Wenya; Wang, Fengying; Zhao, Lei

    2016-09-01

    The objective of this case report is to present the successful use of regional cerebral oxygen saturation (rScO2) monitoring guided cerebral protection for cesarean delivery in a parturient with Takayasu's arteritis at 38weeks' gestation. The parturient presented with impaired cerebral and renal perfusion. Titrated epidural anesthesia was performed. During the procedure, we used rScO2 guided cerebral protection strategies, which helped to optimize cerebral oxygen delivery and prevent cerebral complications.

  20. White Cliffs: Operating Experience

    NASA Technical Reports Server (NTRS)

    Kaneff, S.

    1984-01-01

    The fourteen dish white cliffs solar power station area is remote and subject to extreme environmental conditions, solution of the associated problems required careful and thoughtful attention and the application of resources. Notwithstanding the wide range and harshness of conditions, the difficulties caused by remoteness and the lack of a technological base and the need for relatively rapid demonstration of success, the project has had a very positive outcome. Qualitative and quantitative information and lessons are now available to enable considerable simplifications to be made for a new system, reducing both hardware and operation and maintenance costs. Experience and lessons are presented, particularly in relation to: system performance in various environmental conditions; design philosophies for collectors, the array, control systems, engine and plant; operation and maintenance strategies and cost reducing possibilities. Experience so far gives encouragement for the future of such paraboloidal dish systems in appropriate areas.