bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of an expert system for the interpretation of displacement monitoring data
Authors: Großauer Karl , Schubert Wulf
Published: June 2009

Displacement monitoring has been common practice during tunnel excavation for many decades. The results are usually used to assess the stabilisation process and to adapt excavation and support to the actual conditions. Although monitoring is done routinely on practically all sites, no consistent collection of case histories has yet been established, so the experience gained on completed projects is rarely available for new projects. To better utilise this previous experience, an expert system for the evaluation and interpretation of displacement monitoring data is currently under development. The main component of the system is an expert knowledge base containing normal displacement behaviour for a wide range of geotechnical conditions. Methods required for the identification of such normal displacement situations as well as for clear description of the displacement characteristics have been developed and will be outlined. The check whether the actually observed displacements are normal will be done by means of a comparison with a real displacement scenario from the database. In case a significant deviation is identified, the actual displacement trends will be compared to reference trends characteristic for changing ground conditions and the most probable situation determined. If the degree of correlation is low, then it is very probable that the actual displacements show abnormal behaviour.
Neural correlates of pre‐attentive processing of pattern deviance in professional musicians
Authors: Habermeyer Benedikt , Herdener Marcus , Esposito Fabrizio , Hilti Caroline C. , Klarhöfer Markus , di Salle Francesco , Wetzel Stephan , Scheffler Klaus , Cattapan‐Ludewig Katja , Seifritz Erich
Published: June 2009

Pre‐attentive registration of aberrations in predictable sound patterns is attributed to the temporal cortex. However, electrophysiology suggests that frontal areas become more important when deviance complexity increases. To play an instrument in an ensemble, professional musicians have to rely on the ability to detect even slight deviances from expected musical patterns and therefore have highly trained aural skills. Here, we aimed to identify the neural correlates of experience‐driven plasticity related to the processing of complex sound features. We used functional magnetic resonance imaging in combination with an event‐related oddball paradigm and compared brain activity in professional musicians and non‐musicians during pre‐attentive processing of melodic contour variations. The melodic pattern consisted of a sequence of five tones each lasting 50 ms interrupted by silent interstimulus intervals of 50 ms. Compared to non‐musicians, the professional musicians showed enhanced activity in the left middle and superior temporal gyri, the left inferior frontal gyrus and in the right ventromedial prefrontal cortex in response to pattern deviation. This differential brain activity pattern was correlated with behaviorally tested musical aptitude. Our results thus support an experience‐related role of the left temporal cortex in fast melodic contour processing and suggest involvement of the prefrontal cortex. Hum Brain Mapp, 2009. © 2009 Wiley‐Liss, Inc.
Endogenous cannabinoid signaling is required for voluntary exercise‐induced enhancement of progenitor cell proliferation in the hippocampus
Authors: Hill Matthew N. , Titterness Andrea K. , Morrish Anna C. , Carrier Erica J. , Lee Tiffany T.‐Y. , Gil‐Mohapel Joana , Gorzalka Boris B. , Hillard Cecilia J. , Christie Brian R.
Published: June 2009

Voluntary exercise and endogenous cannabinoid activity have independently been shown to regulate hippocampal plasticity. The aim of the current study was to determine whether the endocannabinoid system is regulated by voluntary exercise and if these changes contribute to exercise‐induced enhancement of cell proliferation. In Experiment 1, 8 days of free access to a running wheel increased the agonist binding site density of the cannabinoid CB1 receptor; CB1 receptor‐mediated GTPγS binding; and the tissue content of the endocannabinoid anandamide in the hippocampus but not in the prefrontal cortex. In Experiment 2, the CB1 receptor antagonist AM251 (1 mg kg−1) was administered daily to animals given free access to a running wheel for 8 days, after which cell proliferation in the hippocampus was examined through immunohistochemical analysis of the cell cycle protein Ki‐67. Voluntary exercise increased proliferation of progenitor cells, as evidenced by the increase in the number of Ki‐67 positive cells in the granule cell layer of the dentate gyrus (DG) in the hippocampus. However, this effect was abrogated by concurrent treatment with AM251, indicating that the increase in endocannabinoid signaling in the hippocampus is required for the exercise‐induced increase in cell proliferation. These data demonstrate that the endocannabinoid system in the hippocampus is sensitive to environmental change and suggest that it is a mediator of experience‐induced plasticity. © 2009 Wiley‐Liss, Inc.
Dose‐dependent long‐term effects of Tat in the rat hippocampal formation: A design‐based stereological study
Authors: Fitting Sylvia , Booze Rosemarie M. , Hasselrot Ulla , Mactutus Charles F.
Published: June 2009

The human immunodeficiency virus type 1 (HIV‐1) protein transactivator of transcription (Tat) is believed to play a critical role in mediating central nervous system (CNS) pathology in pediatric HIV‐1 infection. Long‐term neurotoxicity was investigated in a design‐based stereology study following intrahippocampal injection of Tat on postnatal day (P)10, a time period that approximates the peak in the rats' rate of brain growth and mimics clinical HIV‐1 CNS infection at labor/delivery. The goal was to examine the impact of P10 intrahippocampal Tat injection on the anatomy of the adult hippocampus (5 month) to gain a better understanding about how timing of infection influences the rate of progression of pediatric HIV‐1 infection [cf. Fitting et al. (2008a) Hippocampus 18:135–147]. Male P10 Sprague‐Dawley rats were bilaterally injected with vehicle or one of three different doses of Tat (5, 25, or 50 μg). Unbiased stereological estimates were used to quantify total neuron number (Nissl stain) in five major subregions of the rat hippocampus: granular layer (GL), hilus of the dentate gyrus (DGH), cornu ammonis fields (CA)2/3, CA1, and subiculum (SUB). Glial cells (astrocytes and oligodendrocytes) were quantified in the DGH and SUB. No significant reduction of neuron number was noted for any of the five hippocampal subregions, in contrast to the very prominent reductions reported when Tat was administered on P1 [Fitting et al. (2008a) Hippocampus 18:135–147]. However, for glial cells, the number of astrocytes in the DGH and SUB as well as the number of oligodendrocytes in the DGH were linear dose dependently increased as a function of dose of Tat. In conjunction with previous stereological research [Fitting et al., (2008a) Hippocampus 18:135–147], the present data suggest that variability in the progression of pediatric HIV/acquired immunodeficiency syndrome (AIDS) may be better understood with the knowledge of the factor of timing of HIV‐1 CNS infection. © 2009 Wiley‐Liss, Inc.
Distinct trafficking and expression mechanisms underlie LTP and LTD of NMDA receptor‐mediated synaptic responses
Authors: Peng Yi , Zhao Jiang , Gu Qin‐Hua , Chen Rong‐Qing , Xu Zhuo , Yan Jing‐Zhi , Wang Shan‐Hui , Liu Su‐Yi , Chen Zheng , Lu Wei
Published: June 2009

Although an increasing number of studies have demonstrated the plasticity of NMDA receptor‐mediated synaptic transmission, little is known about the molecular mechanisms that underlie this neurologically important process. In a study of NMDAR‐mediated synaptic responses in hippocampal Schaffer‐CA1 synapses whose AMPA receptor (AMPAR) activity is totally blocked, we uncovered differences between the trafficking mechanisms that underlie the long‐term potentiation (LTP) and long‐term depression (LTD) that can be induced in these cells under these conditions. The LTP‐producing protocol failed to induce a change in the amplitude of NMDAR‐mediated postsynaptic currents (NMDAR EPSCs) in the first 5–10 min, but induced gradual enhancement of NMDAR EPSCs thereafter that soon reached a stable magnitude. This “slow” LTP of NMDAR EPSCs (LTPNMDA) was blocked by inhibiting exocytosis or actin polymerization in postsynaptic cells. By contrast, LTD of NMDAR EPSCs (LTDNMDA) was immediately inducible, and, although it was blocked by the actin stabilizer, it was unaffected by exocytosis or endocytosis inhibitors. Furthermore, concomitant changes in the decay time of NMDAR EPSCs suggested that differential switches in NR2 subunit composition accompanied LTPNMDA and LTDNMDA, and these changes were blocked by the calcium buffer BAPTA or an mGluR antagonist. Our results suggest that LTPNMDA and LTDNMDA utilize different NMDAR trafficking pathways and express different ratios of NMDAR subunits on the postsynaptic surface. © 2009 Wiley‐Liss, Inc.
Chronic social stress during adolescence induces cognitive impairment in aged mice
Authors: Sterlemann Vera , Rammes Gerhard , Wolf Miriam , Liebl Claudia , Ganea Karin , Müller Marianne B. , Schmidt Mathias V.
Published: June 2009

Age‐related cognitive decline is one of the major aspects that impede successful aging in humans. Environmental factors, such as chronic stress, can accelerate or aggravate cognitive deficits during aging. While there is abundant evidence that chronic stress directly affects cognitive performance, the lasting consequences of stress exposures during vulnerable developmental time windows are largely unknown. This is especially true for the adolescent period, which is critical in terms of physical, sexual, and behavioral maturation. Here we used chronic social stress during adolescence in male mice and investigated the consequences of this treatment on cognitive performance during aging. We observed a substantial impairment of spatial memory, but not other memory domains, 12 months after the end of the stress period. This hippocampus‐dependent cognitive dysfunction was supported by concomitant impairment in LTP induction in CA1 neurons in 15‐month‐old animals. Further, we observed a decrease of hippocampal BDNF mRNA and synaptophysin immunoreactivity, suggesting plasticity and structural alterations in formerly stressed mice. Finally, we identified expression changes of specific neurotransmitter subunits critically involved in learning and memory, specifically the NMDA receptor subunit NR2B. Taken together, our results identify possible molecular mechanisms underlying cognitive impairment during aging, demonstrating the detrimental impact of stress during adolescence on hippocampus‐dependent cognitive function in aged mice. © 2009 Wiley‐Liss, Inc.
Encoding and retrieval in a model of the hippocampal CA1 microcircuit
Authors: Cutsuridis Vassilis , Cobb Stuart , Graham Bruce P.
Published: June 2009

It has been proposed that the hippocampal theta rhythm (4–7 Hz) can contribute to memory formation by separating encoding (storage) and retrieval of memories into different functional half‐cycles (Hasselmo et al. (2002) Neural Comput 14:793–817). We investigate, via computer simulations, the biophysical mechanisms by which storage and recall of spatio‐temporal input patterns are achieved by the CA1 microcircuitry. A model of the CA1 microcircuit is presented that uses biophysical representations of the major cell types, including pyramidal (P) cells and four types of inhibitory interneurons: basket (B) cells, axo‐axonic (AA) cells, bistratified (BS) cells and oriens lacunosum‐moleculare (OLM) cells. Inputs to the network come from the entorhinal cortex (EC), the CA3 Schaffer collaterals and medial septum. The EC input provides the sensory information, whereas all other inputs provide context and timing information. Septal input provides timing information for phasing storage and recall. Storage is accomplished via a local STDP mediated hetero‐association of the EC input pattern and the incoming CA3 input pattern on the CA1 pyramidal cell target synapses. The model simulates the timing of firing of different hippocampal cell types relative to the theta rhythm in anesthetized animals and proposes experimentally confirmed functional roles for the different classes of inhibitory interneurons in the storage and recall cycles (Klausberger et al., (2003,2004) Nature 421:844–848, Nat Neurosci 7:41–47). Measures of recall performance of new and previously stored input patterns in the presence or absence of various inhibitory interneurons are employed to quantitatively test the performance of our model. Finally, the mean recall quality of the CA1 microcircuit is tested as the number of stored patterns is increased. © 2009 Wiley‐Liss, Inc.
Repeated measures of serum glucose and insulin in relation to postmenopausal breast cancer
Authors: Kabat Geoffrey C. , Kim Mimi , Caan Bette J. , Chlebowski Rowan T. , Gunter Marc J. , Ho Gloria Y.F. , Rodriguez Beatriz L. , Shikany James M. , Strickler Howard D. , Vitolins Mara Z. , Rohan Thomas E.
Published: June 2009

Experimental and epidemiological evidence suggests that circulating glucose and insulin may play a role in breast carcinogenesis. However, few cohort studies have examined breast cancer risk in association with glucose and insulin levels, and studies to date have had only baseline measurements of exposure. We conducted a longitudinal study of postmenopausal breast cancer risk using the 6% random sample of women in the Women's Health Initiative clinical trials whose fasting blood samples, provided at baseline and at years 1, 3 and 6, were analyzed for glucose and insulin. In addition, a 1% sample of women in the observational study, who had glucose and insulin measured in fasting blood samples drawn at baseline and in year 3, were included in the analysis. We used Cox proportional hazards models to estimate hazard ratios and 95% confidence intervals for the association of baseline and follow‐up measurements of serum glucose and insulin with breast cancer risk. All statistical tests were 2‐sided. Among 5,450 women with baseline serum glucose and insulin values, 190 incident cases of breast cancer were ascertained over a median of 8.0 years of follow‐up. The highest tertile of baseline insulin, relative to the lowest, was associated with a 2‐fold increase in risk in the total population (multivariable hazard ratio 2.22, 95% confidence interval 1.39–3.53) and with a 3‐fold increase in risk in women who were not enrolled in the intervention arm of any clinical trial (multivariable hazard ratio 3.15, 95% confidence interval 1.61–6.17). Glucose levels showed no association with risk. Analysis of the repeated measurements supported the results of the baseline analysis. These data suggest that elevated serum insulin levels may be a risk factor for postmenopausal breast cancer. © 2009 UICC
EGFR and KRAS status of primary sarcomatoid carcinomas of the lung: Implications for anti‐EGFR treatment of a rare lung malignancy
Authors: Italiano Antoine , Cortot Alexis B. , Ilie Marius , Martel‐Planche Ghyslaine , Fabas Thibault , Pop Daniel , Mouroux Jérôme , Hofman Veronique , Hofman Paul , Pedeutour Florence
Published: June 2009

Sarcomatoid carcinomas (SC) of the lung are uncommon malignant tumors composed of carcinomatous and sarcomatous cell components and characterized by a more aggressive outcome than other histological subtypes of nonsmall cell lung cancer (NSCLC). Although epidermal growth factor receptor (EGFR)‐targeted therapies have emerged as a promising therapeutic approach in patients with advanced typical NSCLC such as adenocarcinoma, the potential clinical activity of these drugs in lung SC is still unknown. To investigate this point, we have analyzed the status of 4 EGFR pathways biomarkers in a series of lung SC. EGFR protein expression, EGFR gene copy number, EGFR mutational status and KRAS mutational status were assessed in a series of 22 consecutive cases of primary lung SC. EGFR protein overexpression was observed in all the cases. High level of polysomy (≥4 copies of the gene in >40% of cells) was detected in 5 cases (23%). No EGFR mutation was detected. KRAS mutations were found in 8 patients (38%; Gly12Cys in 6 cases and Gly12Val in 2 cases). The consistent EGFR protein overexpression and the high rate of KRAS mutation may contribute to the poorer outcome of lung SC in comparison with typical NSCLC. The rare incidence of increased EGFR gene copy number, the lack of EGFR mutation and the high rate of KRAS mutation observed in our series also suggest that most patients with lung SC are not likely to benefit from anti‐EGFR therapies. © 2009 UICC
Alcohol consumption and chronic atrophic gastritis: Population‐based study among 9,444 older adults from Germany
Authors: Gao Lei , Weck Melanie N. , Stegmaier Christa , Rothenbacher Dietrich , Brenner Hermann
Published: June 2009

Moderate alcohol consumption has been suggested to facilitate elimination of Helicobacter pylori infection which is a key risk factor for chronic atrophic gastritis (CAG) and gastric cancer. The aim of our study was to assess the association of alcohol consumption with CAG among older adults from Germany. In the baseline examination of ESTHER, a population‐based study conducted in Saarland, serological measurements of pepsinogen I and II (for CAG definition) and H. pylori antibodies were taken in 9,444 subjects aged 50–74 years. Moderate current (<60 g/week) and lifetime (≤51,376 g, lowest quartile) alcohol consumption were found to be associated with significantly reduced CAG risk compared to alcohol abstinence with adjusted odds ratios of 0.71 (0.55–0.90) and 0.73 (0.55–0.96), respectively. Inverse associations with CAG were observed for moderate alcohol consumption from both beer and wine, and were slightly attenuated after additional adjustment for H. pylori infection. Our results are consistent with the hypothesis that moderate alcohol consumption may be inversely related to CAG, partly through facilitating the elimination of H. pylori. However, the observed patterns suggest that other mechanisms are likely to contribute to the association as well. © 2009 UICC
Deconstructing the model minority myth and how it contributes to the invisible minority reality in higher education research
Authors: Museus Samuel D. , Kiang Peter N.
Published: June 2009

A better understanding of the model minority myth of Asian American and Pacific Islanders can help move toward generating an authentic understanding of these students.
Rising to the challenge of conducting research on Asian Americans in higher education
Authors: Museus Samuel D. , Chang Mitchell J.
Published: June 2009

Many challenges to studying Asian Americans in higher education exist, but they are not insurmountable. The urgency of rising to overcome those challenges is discussed.
Implication of groundwater fluctuation on the seasonal salt dynamic in the Harran Plain, south‐eastern Turkey
Authors: Çullu M. A. , Aydemi̇r S. , Qadi̇r M. , Almaca A. , Öztürkmen A. R. , Bi̇lgi̇ç A. , Ağca N.
Published: June 2009

Inefficient farm‐level water management aggravates groundwater fluctuation and salt accumulation particularly in arid and semi‐arid irrigated agriculture. Inappropriate water management practices in the Harran Plain are a good example. A study was carried out to investigate the effect of groundwater fluctuation on the seasonal salt dynamic in four widespread soil series in the Harran Plain with different natural drainage, south‐eastern Turkey. Four profiles were excavated and soil samples were collected seasonally up to 100 cm depth with 10 cm intervals. Similarly, irrigation and groundwater samples were collected from the fields where soil sampling was carried out. Significant seasonal variations in the salt dynamic were observed with the fluctuation levels of the groundwater. Total salt content at 1 m soil depth remained constant during the year, however salt fluctuation throughout the root zone in the growing season exceeded the threshold values of corn, wheat and cotton, commonly grown crops in the region, of 1.7, 6.0 and 7.7 dS m−1, respectively. However, soils with less water fluctuation showed lower salt accumulation in the root zone from May to October. Results also confirmed that soils can be non‐saline, but groundwater salinity, which may not be point specific, requires special attention. Copyright © 2009 John Wiley & Sons, Ltd.
The pervasive absence of compensating differentials
Authors: Bonhomme Stéphane , Jolivet Grégory
Published: June 2009

We study the relation between individual preferences for job amenities (e.g., type of work, job security) and compensating wage differentials in cross‐section. To this end, we estimate a partial equilibrium job search model on panel data from eight European countries. There are five non‐wage job characteristics and two sources of job‐to‐job mobility: on‐the‐job search and reallocation shocks. We also allow for two types of unobserved heterogeneity. We find strong preferences for amenities, especially job security, yet, these preferences do not translate into significant wage differentials in cross‐section. Counterfactual experiments show that one would need extremely low levels of search frictions for compensating differentials to arise. Lastly, a similar exercise on the distribution of job change outcomes reveals the role of constrained job‐to‐job mobility in the absence of compensating wage differentials. Copyright © 2009 John Wiley & Sons, Ltd.
Agricultural cycle and the prevalence of posttraumatic stress disorder: A longitudinal community study in postwar Mozambique
Authors: Igreja Victor , Kleijn Wim , Dias‐Lambranca Beatrice , Hershey Douglas A. , Calero Clara , Richters Annemiek
Published: June 2009

The influence of physical activity on the prevalence and remission of war‐related mental disturbances has never been systematically evaluated. This study examined the influence of participation in the agricultural cycle on the posttraumatic stress disorder (PTSD) prevalence and correlated symptoms longitudinally in postcivil war Mozambique. Prevalence rates were examined in the end and the outset of the agricultural cycle in a community population (N = 240). The agricultural cycle, which is characterized by fluctuations in physical activities, social connectedness, and the sense of purpose in life influences the PTSD prevalence and correlated symptoms. By studying the influence of the agricultural cycle on PTSD prevalence, severe PTSD cases that fail to respond to the agricultural cycle can be identified, and subsequently evaluated regarding the need for specialized care.
On the need for more precise threshold values for chloride initiated corrosion
Authors: Frederiksen J. M.
Published: June 2009

This paper stresses the need for focussing on a better understanding of the term ‘chloride threshold value’ for initiating reinforcement corrosion in concrete structures. It also focuses on the need for more precise values for modelling chloride ingress and for decision making in repair projects and finally on the need for a reliable internationally accepted test method for measuring the chloride threshold value. As a consequence no test results are presented. A provisional formula for design purposes and a test setup for testing the property are reintroduced.
Detecting critical chloride content in concrete using embedded ion selective electrodes – effect of liquid junction and membrane potentials
Authors: Angst U. , Vennesland Ø.
Published: June 2009

When studying critical chloride content in reinforced concrete, the amount of chloride dissolved in the pore solution is an important parameter. Ion selective electrodes offer the possibility of measuring the chloride ion concentration (activity) in the concrete pore solution non‐destructively. However, the potentiometric measurement might be disturbed by, amongst others, diffusion potentials (liquid junction potentials and membrane potentials). Laboratory samples designed to find critical chloride contents often involve chloride ingress by capillary suction, diffusion or migration, and thus chloride and pH profiles are usually present. As a result of these concentration gradients, membrane potentials are established, which markedly affect the determination of the chloride concentration. In addition, liquid junction potentials at the interface of the concrete sample and the reference electrode contribute to the measured potential. Experimental observations in the present work illustrate the effect of liquid junction potentials on the application of ion selective electrodes in concrete. Moreover, the influence of internal membrane potentials has been estimated by a theoretical model.
Atmospheric corrosion of carbon steel at marine sites in Saudi Arabia
Authors: Syed S.
Published: June 2009

Atmospheric corrosion tests, according to ASTM G50‐76, have been carried out in Saudi Arabia, at eight marine sites representing different environmental conditions. Environmental factors such as average temperature, average relative humidity, and deposition rates of atmospheric pollutants (Cl− and SO2) was investigated. X‐ray diffraction has been used to determine the composition of the corrosion products. Corrosion rates have been determined for each sample at each of the exposure sites via loss of weight. The obtained data were used for the classification of atmospheric aggressivity, according to ISO 9223. The results obeyed well with the empirical kinetics equation of the form C = Ktn, where K and C are the corrosion losses in mg/cm2 after 1 and t years of the exposure respectively, and n is constant. Based on n values, the corrosion mechanism of carbon steel is predicted. The major constituent of the rust formed in marine environment is goethite (α‐FeOOH). Samples also show the presence of a large proportion of lepidocrocite (γ‐FeOOH) and small amounts of ferrihydrite and maghemite (α‐Fe203).
Efficient Grafting of Hyperbranched Polyglycerol from Hydroxyl‐Functionalized Multiwalled Carbon Nanotubes by Surface‐Initiated Anionic Ring‐Opening Polymerization
Authors: Zhou Li , Gao Chao , Xu Weijian
Published: June 2009

Biocompatible hyperbranched polyglycerol (HPG) has been covalently grafted from the surfaces of multiwalled carbon nanotubes (MWNTs) by the “grafting from” method based on in situ anionic ring‐opening polymerization. The macroinitiator of hydroxyl‐functionalized MWNTs (MWNT‐OH) with hydroxyl density of 1.39 mmol per gram of nanotubes was prepared by one‐pot nitrene chemistry in N‐methyl‐2‐pyrrolidone (NMP) at 160 °C for 12 h. The amount of HPG grafted from MWNTs can be readily adjusted in a wide range up to 90.8wt.‐% by tuning the feed ratio of glycidol to MWNT‐OH. The resulting HPG‐grafted MWNTs (MWNT‐g‐HPG) nanohybrids were characterized by TGA, FT‐IR, and NMR spectroscopy, HRTEM, and SEM. The as‐prepared nanohybrids show good dispersibility in polar solvents such as water, DMF, DMSO, and methanol. On the basis of numerous functional hydroxyl groups of the HPG grown on MWNTs, fluorescent molecules of rhodamine 6B were conjugated to the surface of MWNT‐g‐HPG by N, N′‐dicyclohexylcarbodiimide (DCC) coupling, affording fluorescent MWNTs. The multifunctional MWNT‐g‐HPG nanohybrids promise potential applications in drug delivery, cell imaging and bioprobing.

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Muscle biopsy substantiates long‐term MRI alterations one year after a single dose of botulinum toxin injected into the lateral gastrocnemius muscle of healthy volunteers
Authors: Schroeder A. Sebastian , Ertl‐Wagner Birgit , Britsch Stefanie , Schröder J. Michael , Nikolin Stefan , Weis Joachim , Müller‐Felber Wolfgang , Koerte Inga , Stehr Maximilian , Berweck Steffen , Borggraefe Ingo , Heinen Florian
Published: June 2009

Despite numerous clinical and experimental studies on botulinum toxin type A (BoNT/A), long‐term alterations of muscle texture and fine structure following BoNT/A treatment have thus far not been studied in normal human skeletal muscle. After obtaining institutional review board approval, we performed a prospective, placebo‐controlled, double‐blinded follow‐up study on two healthy adults using magnetic resonance imaging (MRI) and muscle biopsy to visualize long‐term alterations after a single BoNT/A injection into the lateral head of the gastrocnemius muscle. MRI disclosed a high‐signal‐intensity pattern in short tau inversion recovery sequences, and a reduction of the cross‐sectional area in the BoNT/A‐injected, but not in the saline‐injected contralateral control muscle (at 6 to 9 months in volunteer A: 73%, in B: 62%; at 12 months in A: 88%, and in B: 78%). Enzyme histochemistry, 12 months after injection, confirmed neurogenic atrophy of muscle fibers only in the BoNT/A‐injected muscle. Electron microscopy revealed additional degenerative changes at the neuromuscular junction. The data confirm that MRI is a suitable tool to monitor the long‐term effect of BoNT/A on skeletal muscle. Neurogenic muscle atrophy following a single BoNT/A injection should be taken into consideration when repeated BoNT/A injections into the same muscles are proposed. © 2009 Movement Disorder Society
Tremor on smiling
Authors: Schwingenschuh Petra , Cordivari Carla , Czerny Julia , Esposito Marcello , Bhatia Kailash P.
Published: June 2009

Facial tremor occurring on smiling is a rare phenomenon and has been described (to the best of our knowledge) in the literature only once. We describe two patients who presented with a bilateral facial tremor that occurred only on smiling and other activation of therisorii muscles and had a high frequency of 9 Hz. One patient additionally suffered from young‐onset Parkinson's disease, whereas the other had no further neurological symptoms or signs apart from this tremor. Anti‐parkinsonian medication was unhelpful for the facial tremor in the patient with Parkinson's disease. Tremor on smiling may be a discrete entity or may be associated in some cases of Parkinson's disease. © 2009 Movement Disorder Society
Quantification of pulmonary blood flow (PBF): Validation of perfusion MRI and nonlinear contrast agent (CA) dose correction with HO positron emission tomography (PET)
Authors: Neeb Daniel , Kunz Rainer Peter , Ley Sebastian , Szábo Gábor , Strauss Ludwig G. , Kauczor Hans‐Ulrich , Kreitner Karl‐Friedrich , Schreiber Laura Maria
Published: June 2009

Validation of quantification of pulmonary blood flow (PBF) with dynamic, contrast‐enhanced MRI is still missing. A possible reason certainly lies in difficulties based on the nonlinear dependence of signal intensity (SI) from contrast agent (CA) concentration. Both aspects were addressed in this study. Nine healthy pigs were examined by first‐pass perfusion MRI using gadolinium diethylenetriamine pentaacetic acid (Gd‐DTPA) and HO positron emission tomography (PET) imaging. Calculations of hemodynamic parameters were based on a one‐compartment model (MR) and a two‐compartment model (PET). Simulations showed a significant error when assuming a linear relation between MR SI and CA dose in the arterial input function (AIF), even at low doses of 0.025 mmol/kg body weight (BW). To correct for nonlinearity, a calibration curve was calculated on the basis of the signal equation. The required accuracy of equation parameters (like longitudinal relaxation time) was evaluated. Error analysis estimates <5% over‐/underestimation of the corrected SI. Comparison of PET and MR flow values yielded a significant correlation (P < 0.001) in dorsal regions where signal‐to‐noise ratio (SNR) was sufficient. Changes in PBF due to the correction method were significant (P < 0.001) and resulted in a better agreement: mean values (standard deviation) in units of ml/min/100 ml lung tissue were 59 (15) for PET, 112 (28) for uncorrected MRI, and 80 (21) for corrected MRI. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
A simulation environment for diffusion weighted MR experiments in complex media
Authors: Balls Gregory T. , Frank Lawrence R.
Published: June 2009

Simulations of diffusion in neural tissues have traditionally been limited to analytical solutions, to grid‐based solvers, or to small‐scale Monte Carlo simulations. None of these approaches has had the capability to simulate realistic complex neural tissues on the scale of even a single voxel of reasonable (i.e., clinical) size. An approach is described that combines a Monte Carlo Brownian dynamics simulator capable of simulating diffusion in arbitrarily complex polygonal geometries with a signal integrator flexible enough to handle a variety of pulse sequences. Taken together, this package provides a complete and general simulation environment for diffusion MRI experiments. The simulator is validated against analytical solutions for unbounded diffusion and diffusion between parallel plates. Further results are shown for aligned fibers, varying packing density and permeability, and for crossing straight fibers. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Quantifying endogenous glucose production and contributing source fluxes from a single 2H NMR spectrum
Authors: Nunes Patricia M. , Jones John G.
Published: June 2009

Endogenous glucose production (EGP), gluconeogenic and glycogenolytic fluxes by analysis of a single 2H‐NMR spectrum is demonstrated with 6‐hr and 24‐hr fasted rats. Animals were administered [1‐2H, 1‐13C]glucose, a novel tracer of glucose turnover, and 2H2O. Plasma glucose enrichment from both tracers was quantified by 2H‐NMR analysis of monoacetone glucose. The 6‐hr fasted group (n = 7) had EGP rates of 95.6 ± 13.3 μmol/kg/min, where 56.2 ± 7.9 μmol/kg/min were derived from PEP; 12.1 ± 2.1 μmol/kg/min from glycerol, and 32.1 ± 4.9 μmol/kg/min from glycogen. The 24‐hr fasted group (n = 7) had significantly lower EGP rates (52.8 ± 7.2 μmol/kg/min, P = 0.004 vs. 6 hr) mediated by a significantly reduced contribution from glycogen (4.7 ± 5.9 μmol/kg/min, P = 0.02 vs. 6 hr) while PEP and glycerol contributions were not significantly different (39.5 ± 3.9 and 8.5 ± 1.2 μmol/kg/min, respectively). These estimates agree with previous assays of EGP fluxes in fasted rats obtained by multinuclear NMR analyses of plasma glucose enrichment from 2H2O and 13C‐glucose tracers. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Rapid 3D radiofrequency field mapping using catalyzed double‐angle method
Authors: Wang Dingxin , Zuehlsdorff Sven , Larson Andrew C.
Published: June 2009

A new method is presented for rapid and accurate large volumetric radiofrequency (RF) field (B) mapping. This method is a modification of the double‐angle method (DAM), which accelerates imaging speed and applies 3D acquisition to improve B measurement accuracy. It reduces repetition time and scan time by introducing a catalyzation RF pulse chain at the end of each DAM repetition cycle. The catalyzation pulse chain ensures that, after each TR period, the longitudinal magnetizations reach the same state for both measurements at two flip angles for the DAM so that the long TR requirement (TR ≥ 5 T1) for complete relaxation of longitudinal magnetization of DAM becomes unnecessary. A multi‐echo imaging sequence is additionally incorporated to further improve the efficiency of data acquisition. Simulations demonstrate an excellent flip angle measurement accuracy for catalyzed DAM even with TR << T1. Phantom and in vivo volunteer studies are presented to demonstrate the catalyzation effect upon B mapping and the application of 3D catalyzed DAM for rapid and accurate large volume RF field mapping. Copyright © 2009 John Wiley & Sons, Ltd.
Comparison of MRI signatures in pattern I and II multiple sclerosis models
Authors: Serres Sébastien , Anthony Daniel C. , Jiang Yanyan , Campbell Sandra J. , Broom Kerry A. , Khrapitchev Alexandre , Sibson Nicola R.
Published: June 2009

The majority of individuals with multiple sclerosis (MS) exhibit T‐cell‐ and macrophage‐dominated lesions (patterns I and II; as opposed to III and IV). These lesions, in turn, may be distinguished on the basis of whether or not there are immunoglobulin and complement depositions at the sites of active myelin destruction; such depositions are found exclusively in pattern II lesions. The main aim of this study was to determine whether pattern I and pattern II MS lesions exhibit distinct MRI signatures. We have used a recently described focal MOG‐induced EAE model of the rat brain, which recapitulates many of the hallmarks of pattern II MS; we compared this with our previous work in a delayed type hypersensitivity model of a pattern I type lesion in the rat brain. Demyelinating lesions with extensive inflammation were generated, in which the T2‐weighted signal was increased. Magnetisation transfer ratio (MTR) maps revealed loss and subsequent incomplete recovery of the structure of the corpus callosum, together with changes in tissue water diffusion and an associated increase in ventricle size. Notably, the MTR changes preceeded histological demyelination and may report on the processes leading to demyelination, rather than demyelination per se. Immunohistochemically, these MRI‐detectable signal changes correlated with both inflammatory cell infiltration and later loss of myelin. Breakdown of the blood–brain barrier and an increase in the regional cerebral blood volume were also evident in and around the lesion site at the early stage of the disease. Interestingly, however, the MRI signal changes in this pattern II type MS lesion were remarkably consistent with those previously observed in a pattern I lesion. These findings suggest that the observed signal changes reflect the convergent histopathology of the two models rather than the underlying mechanisms of the disease. Copyright © 2009 John Wiley & Sons, Ltd.
Effects of coping skills training in school‐age children with type 1 diabetes
Authors: Grey Margaret , Whittemore Robin , Jaser Sarah , Ambrosino Jodie , Lindemann Evie , Liberti Lauren , Northrup Veronika , Dziura James
Published: June 2009

Children with type 1 diabetes are at risk for negative psychosocial and physiological outcomes, particularly as they enter adolescence. The purpose of this randomized trial (n = 82) was to determine the effects, mediators, and moderators of a coping skills training intervention (n = 53) for school‐aged children compared to general diabetes education (n = 29). Both groups improved over time, reporting lower impact of diabetes, better coping with diabetes, better diabetes self‐efficacy, fewer depressive symptoms, and less parental control. Treatment modality (pump vs. injections) moderated intervention efficacy on select outcomes. Findings suggest that group‐based interventions may be beneficial for this age group. © 2009 Wiley Periodicals, Inc. Res Nurs Health 32: 405–418, 2009
Tumour suppression by p53: the importance of apoptosis and cellular senescence
Authors: Zuckerman Valentina , Wolyniec Kamil , Sionov Ronit V , Haupt Sue , Haupt Ygal
Published: June 2009

p53 is regarded as a central player in tumour suppression, as it controls programmed cell death (apoptosis) as well as cellular senescence. While apoptosis eliminates cells at high risk for oncogenic transformation, senescence acts as a barrier to tumourigenesis by imposing irreversible cell cycle arrest. p53 can act directly or indirectly at multiple levels of the tumour suppression network by invoking a myriad of mechanisms. p53 induces the extrinsic and intrinsic apoptotic pathways at multiple steps to ensure an efficient death response. This response involves transcriptional activation or repression of target genes, as well as the recently identified microRNAs, and transcription‐independent functions. Importantly, p53 loss of function is required for tumour maintenance. Therefore, therapeutic strategies aimed at reactivation of p53 in tumours emerge as a promising approach for the treatment of cancer patients. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Stem cell transplant in the treatment of childhood biphenotypic acute leukemia
Authors: Park Jeong A. , Ghim Thad T. , Bae Keun wook , Im Ho Joon , Jang Seong Soo , Park Chan Jeong , Chi Hyun Sook , Seo Jong Jin
Published: June 2009

Background

Many studies have found that biphenotypic acute leukemia (BAL) is associated with a poor outcome.

Methods

We retrospectively reviewed the medical records and analyzed clinicopathological data on 25 children with BAL, and correlated outcomes with prognostic factors.

Results

BAL constituted 4.4% of all acute childhood leukemia cases. In terms of immunophenotype, 14 patients had leukemia with myeloid plus B‐lymphoid (M + B) marker, 7 with myeloid plus T‐lymphoid (M + T) marker, and 4 with myeloid plus B‐lymphoid and T‐lymphoid (M + B + T) markers. Overall survival was superior in patients with the M + B immunophenotype (P = 0.004). Hematopoietic stem cell transplantation (HSCT) did not improve either overall survival or event‐free survival compared to chemotherapy alone (hazard ratio 0.98, 95% CI 0.35–2.76, P = 0.966; hazard ratio 1.07, 95% CI 0.41–2.78, P = 0.88). Each of four patients with high‐hyperdiploidy (>50 chromosomes) displayed a good treatment response and long‐term overall survival even though these patients were treated with chemotherapy alone.

Conclusions

Treatment outcomes in childhood BAL patients differed by immunophenotype and cytogenetics. HSCT did not offer a significantly greater survival advantage compared to chemotherapy. While these data suggest that treatment should be individualized and stratified according to biologic characteristics and prognostic factors in BAL, prospective trial data are still needed. Pediatr Blood Cancer 2009;53:444–452. © 2009 Wiley‐Liss, Inc.
Intradural dirofilariasis mimicking a Langerhans cell histiocytosis tumor
Authors: Perret‐Court Audrey , Coulibaly Bema , Ranque Stéphane , Bouvier Corinne , Lena Gabriel , Coze Carole , Verschuur Arnauld
Published: June 2009

We report the case of a 6‐year‐old female who presented a cervical intradural extra‐spinal tumor, initially considered as a Langerhans cell histiocytosis. Additional histological slides revealed a Dirofilaria repens dirofilariasis. The particularity of this case is the intradural location of this filariasis, which usually has a subcutaneous or conjunctival location in human. Pediatr Blood Cancer 2009;53:485–487. © 2009 Wiley‐Liss, Inc.
Aging of polyethylene pipes transporting drinking water disinfected by chlorine dioxide. Part II—Lifetime prediction
Authors: Colin Xavier , Audouin Ludmila , Verdu Jacques , Rozental‐Evesque Magali , Rabaud Benjamin , Martin Florencio , Bourgine Francis
Published: June 2009

This article deals with the failure of polyethylene pipes transporting chlorine dioxide (DOC) disinfected water under pressures of few bars. Accelerated aging tries made at 20 or 40°C show that the antioxidant is rapidly consumed in a superficial layer until a depth of about 1.2 mm. Carbonyl groups appear in a sharper layer of few hundreds micrometers. Natural aging results at various places, for various times up to about 30 years, reveal also a superficial attack with a depth of the order of 1.2 mm. An antioxidant loss by migration, in the whole sample thickness, is also observable. The shape of antioxidant concentration profiles indicates that the crossing of interfaces controls partially the whole migration kinetics. Failures, with brittle cracking, were observed in natural aging, after exposure times of the order of 5–15 years, i.e., far before the expected lifetime (50 years). A kinetic model has been elaborated to predict the time to failure. It is based on a chemical unit, which models the radical processes induced by DOC, and a mechanical unit based on an empirical creep law and a failure criterion depending of the molar mass calculated by the chemical unit. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Origin and polycyclic behaviour of tundra thaw slumps, Mackenzie Delta region, Northwest Territories, Canada
Authors: Kokelj S. V. , Lantz T. C. , Kanigan J. , Smith S. L. , Coutts R.
Published: June 2009

In tundra uplands east of the Mackenzie Delta, retrogressive thaw slumps up to several hectares in area typically develop around lakes. Ground temperatures increase in terrain affected by slumping due to the high thermal conductivity of exposed mineral soils and deep snow accumulation in winter. Mean annual temperatures at the top of permafrost were several degrees warmer in thaw slumps (−0.1°C to −2.2°C) than beneath adjacent undisturbed tundra (−6.1°C to −6.7°C). Simulations using a two‐dimensional thermal model showed that the thermal disturbance caused by thaw slumping adjacent to tundra lakes can lead to rapid near‐surface lateral talik expansion. Talik growth into ice‐rich materials is likely to cause lake‐bottom subsidence and rejuvenation of shoreline slumping. The observed association of thaw slumps with tundra lakes, the absence of active slumps on the shores of drained lakes where permafrost is aggradational and depressions in the lake bottom adjacent to thaw slumps provide empirical evidence that thermal disturbance, talik enlargement and thawing of subadjacent ice‐rich permafrost can drive the polycyclic behaviour (initiation and growth of slump within an area previously affected by slumping) of lakeside thaw slumps. Copyright © 2009 John Wiley & Sons, Ltd. and Her Majesty the Queen in right of Canada.
The environment and permafrost of the Mackenzie Delta area
Authors: Burn C. R. , Kokelj S. V.
Published: June 2009

The Mackenzie Delta, prograding northwestwards into the Beaufort Sea, is North America's largest arctic delta. This Holocene feature is bounded by rolling uplands to the east and the Richardson Mountains to the west. Treeline traverses the region, separating the subarctic boreal forest in southern parts from low‐shrub tundra and sedge wetlands at the coast. The region is experiencing rapid climate change, and mean annual air temperature has increased by more than 2.5°C since 1970. The area was at the margin of the Wisconsinan ice sheet, so that in the uplands the mean annual ground temperature and glacial history control permafrost thickness, which varies from >700 m to <100 m. Ground temperatures in the delta are distinct from the uplands due to the thermal influence of numerous lakes and shifting channels. In the uplands, ground temperatures decrease northwards across treeline in association with a decrease in the thickness of snow cover. Ground temperatures have increased since 1970 in the uplands by approximately 1.5°C in association with rising annual mean air temperature. The increase has been less in the delta south of treeline due to the extensive thermal influence of water bodies on ground temperature. However, in the outer delta, the ground is currently more than 2.5°C warmer than in 1970. The impact of climate change on permafrost is also evident in the thickness of the active layer, which increased on average by 8 cm at 12 tundra sites on northern Richards Island from 1983–2008. Copyright © 2009 John Wiley & Sons, Ltd. and Her Majesty the Queen in right of Canada.