bluuebunny/crossref_metadata_2025_split huggingface dataset:
IgM and IgA anti-erythrocyte autoantibodies induce anemia in a mouse model through multivalency-dependent hemagglutination but not through complement activation
Authors: Baudino Lucie , Fossati-Jimack Liliane , Chevalley Christelle , Martinez-Soria Eduardo , Shulman Marc J. , Izui Shozo 
Published: February 2007

AbstractBy generating IgM and IgA switch variants of the 34-3C IgG2a anti–red blood cell (RBC) autoantibody, we evaluated the pathogenic activity of these 2 isotypes in view of the Fc-associated effector functions (ie, complement activation and polyvalency-dependent agglutination). We found that polymeric forms of 34-3C IgM and IgA anti-RBC autoantibody were as pathogenic as IgG2a, which was the most pathogenic among 4 different IgG subclasses, whereas their monomeric variants completely lacked pathogenic effects. Histological examination showed that 34-3C IgM and IgA autoantibodies caused anemia as a result of multivalency-dependent hemaggultination and subsequent sequestration of RBC in the spleen, in contrast to Fc receptor– and complement receptor–mediated erythrophagocytosis by Kupffer cells with IgG isotypes. In addition, the development of anemia induced by IgM and IgA isotypes of 34-3C antibody and by 2 additional IgM anti-RBC monoclonal autoantibodies was not inhibited at all in C3-deficient mice, indicating the lack of involvement of complement activation in the pathogenesis of IgM- and IgA-induced anemia. Our data demonstrate a remarkably high pathogenic potential of polymeric forms of IgM and IgA anti-RBC autoantibodies due to their ability to induce hemagglutination but completely independent of complement activation.
Evolution of a novel subfamily of nuclear receptors with members that each contain two DNA binding domains
Authors: Wu Wenjie , Niles Edward G , Hirai Hirohisa , LoVerde Philip T 
Published: February 2007

Abstract

Background
Nuclear receptors (NRs) are important transcriptional modulators in metazoans which regulate transcription through binding to the promoter region of their target gene by the DNA binding domain (DBD) and activation or repression of mRNA synthesis through co-regulators bound to the ligand binding domain (LBD). NRs typically have a single DBD with a LBD.

Results
Three nuclear receptors named 2DBD-NRs, were identified from the flatworm Schistosoma mansoni that each possess a novel set of two DBDs in tandem with a LBD. They represent a novel NR modular structure: A/B-DBD-DBD-hinge-LBD. The 2DBD-NRs form a new subfamily of NRs, VII. By database mining, 2DBD-NR genes from other flatworm species (Schmidtea mediterranea and Dugesia japonica), from Mollusks (Lottia gigantean) and from arthropods (Daphnia pulex) were also identified. All 2DBD-NRs possess a P-box sequence of CEACKK in the first DBD, which is unique to 2DBD-NRs, and a P-box sequence of CEGCKG in the second DBD. Phylogenetic analyses of both DBD and ligand binding domain sequences showed that 2DBD-NR genes originate from a common two DBD-containing ancestor gene. A single 2DBD-NR orthologue was found in Arthropoda, Platyhelminths and Mollusca. Subsequent 2DBD-NR gene evolution in Mollusks and Platyhelminths involved gene duplication. Chromosome localization of S. mansoni 2DBD-NR genes by Fluorescent in situ hybridization (FISH) suggests that 2DBD-NR genes duplicated on different chromosomes in the Platyhelminths. Dimerization of Sm2DBDα indicates that 2DBD-NRs may act as homodimers, suggesting either that two repeats of a half-site are necessary for each DBD of 2DBD-NRs to bind to its target gene, or that each 2DBD-NR can recognize multiple sites.

Conclusion

2DBD-NRs share a common ancestor gene which possessed an extra DBD that likely resulted from a recombination event. After the split of the Arthropods, Mollusks and Platyhelminths, 2DBD-NR underwent a recent duplication in a common ancestor of Mollusks, while two rounds of duplication occurred in a common ancestor of the Platyhelminths. This demonstrates that certain NR gene underwent recent duplication in Prostostome lineages after the split of the Prostostomia and Deuterostomia.
Regional distribution of acoustic-based lung vibration as a function of mechanical ventilation mode
Authors: Dellinger R Phillip , Jean Smith , Cinel Ismail , Tay Christina , Rajanala Susmita , Glickman Yael A , Parrillo Joseph E 
Published: February 2007

Abstract
Introduction
There are several ventilator modes that are used for maintenance mechanical ventilation but no conclusive evidence that one mode of ventilation is better than another. Vibration response imaging is a novel bedside imaging technique that displays vibration energy of lung sounds generated during the respiratory cycle as a real-time structural and functional image of the respiration process. In this study, we objectively evaluated the differences in regional lung vibration during different modes of mechanical ventilation by means of this new technology.

Methods
Vibration response imaging was performed on 38 patients on assist volume control, assist pressure control, and pressure support modes of mechanical ventilation with constant tidal volumes. Images and vibration intensities of three lung regions at maximal inspiration were analyzed.

Results
There was a significant increase in overall geographical area (p < 0.001) and vibration intensity (p < 0.02) in pressure control and pressure support (greatest in pressure support), compared to volume control, when each patient served as his or her own control while targeting the same tidal volume in each mode. This increase in geographical area and vibration intensity occurred primarily in the lower lung regions. The relative percentage increases were 28.5% from volume control to pressure support and 18.8% from volume control to pressure control (p < 0.05). Concomitantly, the areas of the image in the middle lung regions decreased by 3.6% from volume control to pressure support and by 3.7% from volume control to pressure control (p < 0.05). In addition, analysis of regional vibration intensity showed a 35.5% relative percentage increase in the lower region with pressure support versus volume control (p < 0.05).

Conclusion
Pressure support and (to a lesser extent) pressure control modes cause a shift of vibration toward lower lung regions compared to volume control when tidal volumes are held constant. Better patient synchronization with the ventilator, greater downward movement of the diaphragm, and decelerating flow waveform are potential physiologic explanations for the redistribution of vibration energy to lower lung regions in pressure-targeted modes of mechanical ventilation.
Extracellular nucleotides mediate LPS-induced neutrophil migration in vitro and in vivo
Authors: Kukulski Filip , Ben Yebdri Fethia , Lefebvre Julie , Warny Michel , Tessier Philippe A , Sévigny Jean 
Published: February 2007

AbstractExtracellular nucleotides are emerging as important inflammatory mediators. Here, we demonstrate that these molecules mediate LPS-induced neutrophil migration in vitro and in vivo. Apyrase, a nucleotide scavenger, reduced the ability of LPS-stimulated monocytes to recruit neutrophils, as assayed using a modified Boyden chamber. This effect resulted from the inhibition of IL-8 release from monocytes. Furthermore, LPS-induced IL-8 release by monocytes was attenuated significantly by P2Y6 receptor antagonists, RB-2 and MRS2578. Reciprocally, UDP, the selective P2Y6 agonist, induced IL-8 release by monocytes. As for LPS, the media of UDP-stimulated monocytes were chemotactic for neutrophils; IL-8 accounted for ∼50% of neutrophil migration induced by the media of LPS- or UDP-treated monocytes in transendothelial migration assays. It is important that in the murine air-pouch model, extracellular nucleotides were instrumental in LPS-induced neutrophil migration. Altogether, these data imply that LPS induces the release of nucleotides from monocytes and that by autocrine stimulation, the latter molecules regulate neutrophil migration caused by Gram-negative bacteria, suggesting a proinflammatory role of extracellular nucleotides in innate immunity.
Evaluation of the Performance of Randomized versus Fixed Time Schedules for Quality Control Procedures
Authors: Parvin Curtis A , Robbins Sanford 
Published: February 2007

Abstract
Background: Although minimum regulatory standards exist for determining QC testing frequency, decisions regarding when and how to run QC samples are not standardized. Most QC testing strategies test control samples at fixed time intervals, often placing the samples in the same position on an instrument during subsequent QC events and leaving large gaps of time when control samples are never run, yet patient samples are being tested.
Methods: Mathematical derivations and computer simulation were used to determine the expected waiting time between an out-of-control condition and the next scheduled QC test for various QC testing strategies that use fixed or random intervals between QC tests.
Results: Scheduling QC tests at fixed intervals yields an average time between the occurrence of an out-of-control error condition and the next scheduled QC test that is equal to half of the fixed time interval. This performance was the best among the QC scheduling strategies investigated. Near-optimal performance, however, was achieved by randomly selecting time intervals between QC events centered on the desired expected interval length, a method that provides variation in QC testing times throughout the day.
Conclusions: If the goal is to vary QC testing times throughout the day while maintaining the shortest expected length of time between error conditions and the next scheduled QC test, then a near-optimal QC scheduling strategy combines randomly selected time intervals centered on the desired length of time between QC events with fixed time intervals.
Vermischte physikalische Bemerkungen
Authors: Parrot  
Published: March 2007

AbstractGänzliche Umschaffung der Hygrometrie; neue auf bewährte Versuche gegründete Theorie der wässerigen Meteore; jetziger Zustand und fernere Bearbeitung der Meteorologie. ‐ 2. Ueber Berthollet's Vertheidigung des Phosphor‐Eudiometers gegen Hrn. von Humboldt; Parrot's verbessertes Phosphor‐Oxygenometer und dessen Gebrauch; eine gasförmige Phosphorsäure; und den wahren Sauerstoffgehalt der atmosphärischen Luft. ‐ 3. Wie liessen sich Gewitter unschädlich machen?
NMR functional imaging using a tailored RF gradient echo sequence: A true susceptibility measurement technique
Authors: Cho Zang‐Hee , Ro Yong‐Man , Park Sung‐Taek , Chung Sonn‐Chul 
Published: March 2007

AbstractThe tailored radio frequency gradient echo (TRFGE) technique that has been used in venography (Cho et al., Magn. Reson. Med. 28, 25‐38, 1992; Ro, Cho, Magn. Reson. Mod. 28, 237, 1992) is applied to functional imaging. The TRFGE technique has the advantage that it is sensitive to the field gradient created by the susceptibility effect, thereby enhancing only the signals from the regions with local field gradient In addition, the method is insensitive to the in‐flow effect, especially from the arterial blood. The latter further simplifies the functional MRI data analysis. The TRFGE sequence is, therefore, suitable for functional MR imaging for which true susceptibility effect measurements are of prime importance. To examine the TRFGE functional imaging systematically, experiments with various imaging parameters such as flip angle a, repetition time, and echo time were performed and the results were compared with the data obtained from the conventional gradient echo functional MR imaging. The experimental results shown were all obtained from human volunteers with a 2.0T whole body MRI system.
Temperature mapping using water proton chemical shift obtained with 3D‐MRSI: Feasibility in vivo
Authors: Kuroda Kagayaki , Suzuki Yutaka , Ishihara Yasutoshi , Okamoto Kazuya , Suzuki Yoshinori 
Published: March 2007

AbstractThis article discusses the applicability to a living animal of the temperature mapping method using the water proton chemical shift obtained with three‐dimensional magnetic resonance spectroscopic imaging (3D‐MRSI). There are several sources of error in obtaining the spectra with 3D‐MRSI: signal noise, limitation in the frequency resolution due to the finite signal length, intravoxel inhomogeneity in the static magnetic field, and variation in the magnetic field due to the eddy current magnetic field. A spectral estimation method called phase deduction complex Lorentzian fitting (PD‐CLF) was proposed. Numerical simulations demonstrated that this method reduces the error in the chemical shift to one third of that obtained with the simple frequency subtraction method that uses zero‐padded first Fourier transformation (FFT). The temperature images obtained using 3D‐MRSI with PD‐CLF clearly visualized the changes and distribution of temperature in an anesthetized rat.
Proton exchange rates from amino acid side chains— implications for image contrast
Authors: Liepinsh Edvards , Otting Gottfried 
Published: March 2007

AbstractThe proton exchange rates between water and the hydroxyl protons of threonine, serine, tyrosine, the amino protons of lysine, and the guanidinium protons of arginine were measured in the pH range 0.5 to 8.5 and for the temperatures 4°C, 10°C, 20°C, 30°C, and 36°C. The intrinsic exchange rates of the hydroxyl and amino protons at pH 7.0°C and 36°C were found to be in the range 700 to about 10,000 s−1. In addition, the exchange catalysis by phosphate, carbonate, carboxyl‐, and amino‐groups was investigated. The presence of these exchange catalysts at physiological concentrations increased the proton exchange rates from hydroxyl and amino groups several fold. The proton exchange rates are sufficiently fast that the total magnetization transfer between biomolecules and free bulk water is not rate limited by the proton exchange rate, but by the intramolecular cross‐relaxation rates between the exchangeable and nonexchangeable protons of the biomolecules. Since the cross‐relaxation rates between surface hydration water molecules and biomolecules are usually vanishingly small because of too rapid exchange with the free bulk water, it is proposed that the contrast in MR images is a fingerprint of the number of the exchangeable protons from OH and NH groups of the tissue, as far as the contrast depends on the magnetization transfer between biomolecules and water.
Use of nitroxides for assessing perfusion, oxygenation, and viability of tissues: In vivo EPR and MRI studies
Authors: Gallez Bernard , Bacic Goran , Goda Fuminori , Jiang Jinjie , O′Hara Julia A. , Dunn Jeff F. , Swartz Harold M. 
Published: March 2007

AbstractRelative perfusion, pO2, and bioreduction were measured simultaneously in wVo in tissues in mice by following changes in the intensity and shape of the EPR spectra of nitroxides injected directly into the tissues, using low frequency (1.1 GHz) localized EPR spectroscopy. Using normal and blood flow restricted gastrocnemius muscles it was shown that the decrease of the EPR signals of the nitroxides in tissues was due principally to perfusion, which redistributed the nitroxides. Changes in pO2 were reflected by changes of the linewidth; only a perdeuterated nttroxide with a narrow line was an adequate indicator for this parameter. This technique was applied experimental murine tumors (MTG‐B and RIF‐1) to determine the perfusion and pO2 in these relatively hypoxic model tumor systems. Using the paramagnetic properties of the nitroxides to enhance T1‐weighted MR images, heterogeneity in perfusion in individual tumors was demonstrated.
Dynamic uncoupling and recoupling of perfusion and oxidative metabolism during focal brain activation in man
Authors: Frahm Jens , Krüger Gunnar , Merboldt Klaus‐Dietmar , Kleinschmidt Andreas 
Published: March 2007

AbstractChanges in glucose consumption, lactate production, and blood oxygenation were measured during prolonged neuronal activation (4–6 min) in human primary visual cortex using dynamic magnetic resonance spectroscopy and imaging. A decrease of steady‐state glucose by 40% because of enhanced use by 21% was accompanied by a transient accumulation of lactate with a peak value of 170% 2.5 min after stimulation onset Rapid blood hyperoxygenation indicating „uncoupling”︁ of blood flow and oxidative metabolism was followed by a return to basal levels over 3 min. Thus, initial nonoxidative glucose consumption during functional activation is gradually complemented by a slower adjustment of oxidative phosphorylation that „recouples”︁ perfusion and oxygen consumption at a new equilibrium.
Continuous assessment of relative cerebral blood volume in transient ischemia using steady state susceptibility‐contrast MRI
Authors: Hamberg Leena M. , Boccalini Pia , Stranjalis George , Hunter George J. , Huang Zhihong , Halpern Elkan , Weisskoff Robert M. , Moskowitz Michael A. , Rosen Bruce R. 
Published: March 2007

AbstractThe utility of a noninvasive steady state susceptibility‐contrast MRI technique for continuous measurement of relative cerebral blood volume (rCBV) during global transient ischemia and subsequent hyperemia in a feline ischemia model is demonstrated. The measurements were obtained during a 10‐min period of occlusion and 1‐h period of reperfusion. Maximal hyperemic responses in gray matter, basal ganglia, and white matter (observed at 7,7, and 5 min, respectively) were 1.9 ± 0.5,1.8 ± 0.3, and 1.7 ± 0.6 times greater than baseline CBV (mean ± SEM). Thirty to forty minutes after onset of reperfusion, CBV returned to normal. Thereafter, it decreased below baseline, nearing the control level by 1 h after onset of reperfusion. Steady state susceptibility‐contrast MRI permits continuous, in vivo mapping of alterations in CBV.
Simultaneous multicompartment intracellular Ca2+ measurements in the perfused heart using 19F NMR spectroscopy
Authors: Yanagida Shigeki , Luo Cameron S. , Balschi James A. , Pohost Gerald M. , Pike Martin M. 
Published: March 2007

AbstractAlthough Ca2+ transport regulation at subcellular organelles is of great interest, only limited methodology has been available for measuring organellar [Ca2+] levels. The present study employs the 19F NMR resonance frequency of 4F‐BAPTA to measure free [Ca2+]. In 4F‐BAPTA loaded perfused rabbit hearts, two 19F NMR resonances were clearly observed. The frequency of one was consistent with cytosolic [Ca2+] levels. Responses to agents that alter sarcoplasmic reticulum function identified the other resonance as originating from that organelle. The experiments demonstrate the utility of NMR shift indicator methodology in obtaining simultaneous multi‐compartment intracellular [Ca2+] measurements and in enabling organellar [Ca2+] measurements to be made from within intact living tissue.
Myocardial perfusion and function in dogs with moderate coronary stenosis
Authors: Kraitchman Dara L. , Wilke Norbert , Hexeberg Erik , Jerosch‐Herold Michael , Wang Ying , Parrish Todd B. , Chang Cheng‐Ning , Zhang Yi , Bache Robert J. , Axel Leon 
Published: March 2007

AbstractMRI studies of first‐pass contrast enhancement with polylysine‐Gd‐DTPA and myocardial tagging using spatial modulation of magnetization (SPAMM) were performed to assess the feasibility of a combined regional myocardial blood flow and 2D deformation exam. Instrumented closed‐chest dogs were imaged at a baseline control state (Cntl) followed by two interventions: moderate coronary stenosis (St) achieved by partial occlusion of the left anterior descending (LAD) and moderate coronary stenosis with dobutamine loading (StD). Hypoperfusion of the anterior region (ANT) of the myocardium (LAD distribution) relative to the posterior wall (POS) based on the upslope of the signal intensity time curve from the contrast‐enhanced MR images was demonstrated only with dobutamine loading (ANT:POS Cntl=1.077 ± 0.15 versus ANT:POS StD=0.477 ± 0.11, P<0.03) and was confirmed with radio‐labeled microspheres measurements (ANT:POS Cntl=1.18 ± 0.2 ml/min/g versus ANT:POS StD=0.44 ± 0.1 ml/min/g; P<0.002). Significant changes in regional myocardial shortening were only seen in the StD state (P<0.02); the anterior region showed impaired myocardial shortening with dobutamine loading (P=NS), whereas the nonaffected POS region showed a marked increase in shortening when compared with Cntl (Cntl=0.964 ± 0.02 versus StD=0.884 ± 0.03; P<0.001). These results demonstrate that an integrated quantitative assessment of regional myocardial function and semiquantitative assessment of myocardial blood flow can be performed noninvasively with ultrafast MRI.
Evaluation of methemoglobin as an autologous intravascular MRI contrast agent
Authors: Duewell Stefan , Kasserra Claudia E. , Jezzard Peter , Balaban Robert S. 
Published: March 2007

AbstractMethemoglobin (MetHb) was evaluated as an intravascular paramagnetic contrast agent. Methemoglobin formation was induced by 4‐dimethylaminophenol (4‐DMAP), causing a reduction in blood T2* in vitro. The 4‐DMAP generated metHb with a time constant of 62 s. A 4‐DMAP bolus did not decrease measurably the signal intensity in the in vivo rabbit kidney in the first pass. At steady state, a MetHb concentration of 24.8 ± 2.3% resulted in a signal decrease of 9.2 ± 2.6% in the kidney. Methemoglobin is an effective vascular T2* relaxation agent, but the formation of MetHb by 4‐DMAP is too slow for first‐pass imaging. A more effective conversion agent resulting in a bolus of at least 25% MetHb within 5 s would result in a detectable first‐pass signal and a viable contrast technique.
Substrate selection early after reperfusion of ischemic regions in the working rabbit heart
Authors: Solomon Michael A. , Jeffrey F. Mark H. , Storey Charles J. , Sherry A. Dean , Malloy Craig R. 
Published: March 2007

AbstractSeveral substrates are available in vivo for oxidation by the myocardium. Although substrate selection has been studied extensively in normoxic myocardium, relatively little is known about substrate preference very early during reperfusion after ischemia. Carbon‐13 isotopomer analysis was used to study substrate usage by nonischemic and reperfused‐ischemic myocardium in a working heart that was subjected to 15 min of regional ischemia and reperfused for 5 min. Compared with nonischemic myocardium, the contribution of acetoacetate to acetyl coenzyme A was increased in the reperfused‐ischemic region, and the contribution of exogenous lactate was decreased. Free fatty acid oxidation, however, was not different in the two regions. These results indicate that (1) early during reperfusion, ketone body oxidation may be more significant than has been emphasized, (2) the relative contribution of fatty acids to acetyl coenzyme A is not sensitive to ischemia followed by reperfusion, and (3) Carbon‐13 magnetic resonance spectroscopy methods may be used for analysis of spatial heterogeneity of metabolism in the heart.
Automated feature extraction for the classification of human in vivo13C NMR spectra using statistical pattern recognition and wavelets
Authors: Tate A. Rosemary , Watson Des , Eglen Stephen , Arvanitis Theodores N. , Thomas E. Louise , Bell Jimmy D. 
Published: March 2007

AbstractIf magnetic resonance spectroscopy (MRS) is to become a useful tool in clinical medicine, it will be necessary to find reliable methods for analyzing and classifying MRS data. Automated methods are desirable because they can remove user bias and can deal with large amounts of data, allowing the use of all the available information. In this study, techniques for automatically extracting features for the classification of MRS in vivo data are investigated. Among the techniques used were wavelets, principal component analysis, and linear discriminant function analysis. These techniques were tested on a set of 75 in vivo 13C spectra of human adipose tissue from subjects from three different dietary groups (vegan, vegetarian, and omnivore). It was found that it was possible to assign automatically 94% of the vegans and omnivores to their correct dietary groups, without the need for explicit identification or measurement of peaks.