bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stage of the estrous cycle at the time of pregnant mare's serum gonadotropin injection affects pre‐implantation embryo development in vitro in the mouse
Authors: Tarín Juan J. , Pérez‐Albalá Sonia , Gómez‐Piquer Vanessa , Hermenegildo Carlos , Cano Antonio 
Published: August 2002

AbstractThe present study aims to analyze in the mouse the effect of the stage of the estrous cycle at the time of pregnant mare's serum gonadotropin (PMSG) injection on fertilization of ovulated cumulus‐enclosed oocytes and later embryo development in vitro to the blastocyst stage. Quality of blastocysts was evaluated by staining and counting of total number of nuclei, mitotic index, percentage of apoptotic nuclei, and cell allocation to the inner cell mass (ICM) and trophectoderm (TE) lineage. Superovulation of hybrid (C57Bl/6JIco female × CBA/JIco male) female mice of 4–6 weeks of age was induced by a priming injection of PMSG at different stages of the estrous cycle followed after a 48‐hr interval by human chrorionic gonadotropin. Our data indicate that injection of PMSG at the estrus phase gives the best outcome whereas injection of PMSG at the diestrus‐1 or diestrus‐2 phase provides the worst results. In fact, (1) total number of oocytes ovulated, number of ovulated oocytes enclosed by cumulus cells, and number of TE cells in day‐5 blastocysts were significantly lower in diestrus‐1 females than in estrus, diestrus‐2 and proestrus mice; (2) percentage of day‐5 blastocysts and total number of cells in day‐5 blastocysts were lower in diestrus‐1 and diestrus‐2 females than in estrus and proestrus mice; and (3) percentage of apoptotic nuclei in day‐5 blastocysts was lower in estrus mice than in diestrus‐1, diestrus‐2, or proestrus females. These data endorse previous studies suggesting that administration of gonadotropins in mice should be synchronized with the innate estrous cycle of females. Mol. Reprod. Dev. 62: 312–319, 2002. © 2002 Wiley‐Liss, Inc.
Cloned pigs generated from cultured skin fibroblasts derived from a H‐transferase transgenic boar
Authors: Bondioli Kenneth , Ramsoondar Jagdeece , Williams Barry , Costa Cristina , Fodor William 
Published: August 2002

AbstractCloned pigs were produced from cultured skin fibroblasts derived from a H‐transferase transgenic boar. One 90 day fetus and two healthy piglets resulted from nuclear transfer by fusion of cultured fibroblasts with enucleated oocytes. The cells used in these studies were subjected to an extensive culture time, freezing and thawing, and clonal expansion from single cells prior to nuclear transfer. PCR and FACS analysis determined that the cloned offspring contained and expressed the H‐transferase transgene. Microsatellite analysis confirmed that the clones were genetically identical to the boar. The cell culture and nuclear transfer procedures described here will be useful for applications requiring multiple genetic manipulations in the same animal. Mol. Reprod. Dev. 60: 189–195, 2001. © 2001 Wiley‐Liss, Inc.
Effect of polyunsaturated fatty acid supplementation on biophysical parameters and chilling sensitivity of ewe oocytes
Authors: Zeron Yoel , Sklan David , Arav Amir 
Published: August 2002

AbstractFat supplementation in the diet influences reproductive performance of lactating ruminants. Changes in the fat supply alter fatty acid composition and this can affect physical properties of cell membranes. This study examined the effect of rumen bypass polyunsaturated fatty acid (PUFA) supplementation on oocyte quality, chilling sensitivity, and lipid phase transition in oocytes of the sheep. Ewes were fed a diet supplemented with calcium soaps of fish oil for 13 weeks. More follicles and oocytes were found in the ovaries of ewes supplemented with PUFA than in control ewes. The number of high‐quality oocytes was higher in ewes fed PUFA than in control ewes (74.3 and 57.0%, P < 0.05, respectively). Evaluation of phospholipid fatty acid composition indicated that PUFA were present in small proportions in oocytes, and eicosapentaenoic acid and docosahexaenoic acid were absent. Supplementation with PUFA increased the proportion of long chain unsaturated fatty acid in the plasma and cumulus cells phospholipids by 7.4 and 12.7%, respectively (P < 0.05).Integrity of oocyte membranes following chilling (16°C, 15 min) was improved by PUFA supplementation increasing from 62.5 to 90.0% (P < 0.05). Due to changes in the oocyte's fatty acid profile, physical properties of the membrane were changed and the midpoint temperature of lipid transition reduced by 11°C. These results suggest that supplementation of rumen bypass PUFA to ruminant diets can change fatty acid composition of follicle components and influence parameters such as number and quality of oocytes and their chilling resistance. Mol. Reprod. Dev. 61: 271–278, 2002. © 2002 Wiley‐Liss, Inc.
Systematic review of chorioamnionitis and cerebral palsy
Authors: Wu Yvonne W. 
Published: August 2002

AbstractIn a recent meta‐analysis evaluating the relationship between chorioamnionitis and cerebral palsy, we found that chorioamnionitis is a risk factor for both cerebral palsy and cystic periventricular leukomalacia (cPVL). The current paper extends the meta‐analysis by including studies published in the year 2000, and by further evaluating the causes of heterogeneity among individual study results. Using a random effects model, clinical chorioamnionitis was significantly associated with both cerebral palsy (RR 1.9, 95% CI 1.5–2.5) and cPVL (RR 2.6, 95% CI 1.7–3.9). Sources of heterogeneity included widely varying practices in the diagnosis of clinical chorioamnionitis, different gestational age characteristics, and varying study year. We conclude that based on the available literature, chorioamnionitis is a risk factor for both cerebral palsy and cPVL. MRDD Research Reviews 2002;8:25–29. © 2002 Wiley‐Liss, Inc.
In utero infection and adult schizophrenia
Authors: Brown Alan S. , Susser Ezra S. 
Published: August 2002

AbstractWe review emerging evidence indicating that in utero exposure to infection is a risk factor for schizophrenia. It is hypothesized that a prenatal infection increases the liability to schizophrenia in adulthood by adversely affecting the maturation of critical brain structural and functional components implicated in the pathogenesis and pathophysiology of the disorder. Early evidence for a role of in utero infection includes investigations linking schizophrenia with birth during the winter and in urban regions, and ecologic studies demonstrating associations between influenza epidemics and births of pre‐schizophrenic patients. The findings of the latter studies are, however, equivocal. To more rigorously address this question, our group has used increasingly sophisticated research designs that incorporate more refined measures of exposure and outcome, and continuous follow‐up of treated cases. This work has already yielded several intriguing findings, including associations between schizophrenia and two in utero infections—rubella and respiratory infection. We also describe our ongoing birth cohort investigations that are expected to advance this work further, including studies that utilize maternal serum samples drawn during pregnancy of offspring who were later diagnosed with schizophrenia. MRDD Research Reviews 2002;8:51–57. © 2002 Wiley‐Liss, Inc.
Living circumstances of children and adults with mental retardation or developmental disabilities in the united states, canada, england and wales, and australia
Authors: Braddock David , Emerson Eric , Felce David , Stancliffe Roger J. 
Published: August 2002

AbstractThe purpose of this article was to collate evidence to describe where people with mental retardation or developmental disabilities live in five developed countries: United States, Canada, England, Wales, and Australia. Family homes are important dwelling places for people with mental retardation. They are the home of the great majority of children with mental retardation and a considerable proportion of adults with mental retardation. The likelihood of placement outside the family home increases with adulthood and progressively as people age. Adults with mental retardation live in a wide variety of settings, with formal residential provision frequently dependent on the arrangements that the authorities responsible for providing service support have chosen to make. There has been a considerable move away from accommodating people in large segregated and geographically isolated institutions in the countries considered. However, the current range of accommodation includes much with a distinctively different character to the homes where other citizens live. Many people still live in larger groups than would be ordinarily found in typical homes and this may necessitate departure from the architectural norm. In all of the countries considered, there has been a recent trend towards small community settings, compatible with typical housing architecture. This appears furthest advanced in the U.S. but is discernible elsewhere. Availability of residential services at a national level varies between 100 and 155 places per 100,000 total population. Regional variation within countries is even greater. In no case is the national availability considered adequate to meet the demand arising from changing need or expectations. MRDD Research Reviews 7:115&ndash;121, 2001. &copy; 2001 Wiley&hyphen;Liss, Inc.
Role of excitatory amino acids in developmental epilepsies
Authors: Raol Y.H. , Lynch David R. , Brooks‐Kayal Amy R. 
Published: August 2002

AbstractAltered excitatory amino acid (EAA) neurotransmission, mediated primarily by glutamate, is a major cause of the imbalance of excitation and inhibition which characterizes both early development and epileptogenesis. Glutamate's actions are mediated by three classes of receptors: NMDA, non‐NMDA (AMPA and kainate), and metabotropic. Several features of normal EAA development contribute to hyperexcitability in the immature brain, making it more prone to development of seizures. These features include increased density of NMDA receptors, differences in NMDA receptor subunit composition and activation kinetics, which result in reduced voltage‐dependent Mg2+ blockade and longer receptor openings in early development. Also, the unique subunit composition of AMPA receptors present at synapses during early development results in increased Ca2+ influx. These and other differences in EAA signaling, in combination with developmental alterations in inhibitory neurotransmission, contribute to the increased seizure susceptibility seen in young animals and children. In turn, seizures themselves may alter EAA neurotransmission in an age‐dependent manner. Age related changes in excitatory neurotransmission may, therefore, lead to differences in basic mechanisms of epileptogenesis between the immature and mature brain, and may also alter the activity and efficacy of antiepileptic drugs in the pediatric age group. MRDD Research Reviews 2001;7:254–260. © 2001 Wiley‐Liss, Inc.
Role of glutamine in cerebral nitrogen metabolism and ammonia neurotoxicity
Authors: Cooper Arthur J.L. 
Published: August 2002

AbstractAmmonia enters the brain by diffusion from the blood or cerebrospinal fluid, or is formed in situ from the metabolism of endogenous nitrogen‐containing substances. Despite its central importance in nitrogen homeostasis, excess ammonia is toxic to the central nervous system and its concentration in the brain must be kept low. This is accomplished by the high activity of glutamine synthetase, which is localized in astrocytes and which permits efficient detoxification of incoming or endogenously generated ammonia. The location also permits the operation of an intercellular glutamine cycle. In this cycle, glutamate released from nerve terminals is taken up by astrocytes where it is converted to glutamine. Glutamine is released to the extracellular fluid to be taken up into the nerve cells, where it is converted back to glutamate by the action of glutaminase. Most extrahepatic organs lack a complete urea cycle, and for many organs, including the brain, glutamine represents a temporary storage form of waste nitrogen. As such, glutamine was long thought to be harmless to the brain. However, recent evidence suggests that excess glutamine is neurotoxic. Hyperammonemic syndromes (e.g., liver disease, inborn errors of the urea cycle, Reye's disease) consistently cause astrocyte pathology. Evidence has been presented that hyperammonemia results in increased formation of glutamine directly in astrocytes, thereby generating an osmotic stress to these cells. This osmotic stress results in impaired astrocyte function, which in turn leads to neuronal dysfunction. In this review a brief overview is presented of the role of glutamine in normal brain metabolism and in the pathogenesis of hyperammonemic syndromes. MRDD Research Reviews 2001;7:280–286. © 2001 Wiley‐Liss, Inc.
Estimation of local aortic elastic properties with MRI
Authors: Vulliémoz Serge , Stergiopulos Nikos , Meuli Reto 
Published: August 2002

AbstractAortic compliance and pulse wave velocity (PWV) are important determiners of heart load, and are clinically useful indices of cardiovascular risk. Most direct methods to derive them require invasive pressure measurement. In this work a noninvasive technique to evaluate aortic compliance and PWV using MRI is proposed. MRI magnitude and phase images to measure area and flow in the ascending aorta were acquired in a group of 13 young healthy subjects. Assuming that the early systolic part of the wave was unidirectional and reflectionless, PWV was determined as the ratio between flow and area variations at early systole. Our results were compared to pulse wave velocities derived from a direct transit time, and to one using ascending aortic area and peripheral brachial pulse pressure. The new method proved to be accurate and in good agreement with the transit time method, as well as with previously published results. Magn Reson Med 47:649–654, 2002. © 2002 Wiley‐Liss, Inc.
Assessment of a potential tumor‐seeking manganese metalloporphyrin contrast agent in a mouse model
Authors: Takehara Yasuo , Sakahara Harumi , Masunaga Hatsuko , Isogai Satoshi , Kodaira Nami , Sugiyama Masahiro , Takeda Hiroyasu , Saga Tsuneo , Nakajima Susumu , Sakata Isao 
Published: August 2002

AbstractThe performance of a newly developed potential tumor‐seeking magnetic resonance (MR) contrast agent α‐Aqua‐13,17‐bis(1‐carboxypropionyl) carbamoylethyl‐3,8‐bis(1‐phenethyloxyethyl)‐β‐hydroxy‐2,7,12,18‐tetramethyl‐porphyrinato manganese (III) (HOP‐8P) was tested using a mouse model. Tumor‐bearing (SCC‐VII) mice were imaged using a 1.5T MR imager before and after intravenous administration of 0.1 mmol/kg of HOP‐8P. A biodistribution analysis was performed using an optical emission spectrometer. Significant enhancement of the transplanted tumor was observed in MR images 24 h after intravenous injection of HOP‐8P. The biodistribution assessment of manganese also correlated with the results of the imaging study. During the 24‐h period following contrast administration, HOP‐8P was consistently cleared from the circulation, liver, kidneys, and muscle; however, it was progressively accumulated within the tumor. HOP‐8P is a promising tumor‐seeking metalloporphyrin MR contrast agent with a wide imaging window. Magn Reson Med 47:549–553, 2002. © 2002 Wiley‐Liss, Inc.
In vivo 1H2O T measurement in the human occipital lobe at 4T and 7T by Carr‐Purcell MRI: Detection of microscopic susceptibility contrast
Authors: Bartha Robert , Michaeli Shalom , Merkle Hellmut , Adriany Gregor , Andersen Peter , Chen Wei , Ugurbil Kamil , Garwood Michael 
Published: August 2002

AbstractA high‐resolution spin‐echo imaging method is presented (called CP‐LASER) which exploits the spin refocusing capability of an adiabatic Carr‐Purcell (CP) pulse sequence to measure apparent 1H2O transverse relaxation (T) and generate contrast based on microscopic tissue susceptibility. High‐resolution CP‐LASER images of the human occipital lobe were acquired at four different echo times from six subjects at 4T and eight subjects at 7T to investigate the effect of magnetic field strength (B0) and the CP interpulse time (τcp) on T. Susceptibility contrast was identified and T was quantified for long τcp (>10 ms) and short τcp (7 ms at 4T and 6 ms at 7T) in gray matter, white matter, and cerebral spinal fluid. The 1H2O relaxation rate constants (1/T) of gray and white matter each increased approximately linearly with field strength and T was inversely related to τcp. The average T value of gray matter was 19% and 9% smaller than that of white matter at 4T and 7T, respectively. These results are consistent with higher levels of compartmentalized ferritin and increased blood volume in gray matter compared to white matter in this region of the brain. Magn Reson Med 47:742–750, 2002. © 2002 Wiley‐Liss, Inc.
Noninvasive in vivo oximetric imaging by radiofrequency FT EPR
Authors: Subramanian Sankaran , Yamada Ken‐Ichi , Irie Akira , Murugesan Ramachandran , Cook John A. , Devasahayam Nallathamby , Van Dam Gootzian M. , Mitchell James B. , Krishna Murali C. 
Published: August 2002

AbstractA novel method, called relaxo‐oximetry, for rapid spatially resolved in vivo measurements of oxygen concentration using time‐domain radiofrequency (RF) electron paramagnetic resonance (EPR) is described. Time‐domain data from triaryl methyl (TAM)‐based single‐electron contrast agents were processed by systematic deletion of the initial time points to arrive at T‐weighted discrimination of signal amplitudes. In experiments involving phantoms, the line widths [∼ (T)−1] increased as a function of oxygen, and the slope (line width/pO2) was the same for both absorption‐ and magnitude‐mode line shapes. Line widths derived from T weighting and the computed pO2 values agreed favorably with the measured ones from phantoms of known oxygen tension. In vivo relaxo‐oximetry was performed on C3H mice, and it was found that the liver was more hypoxic than the kidneys. For tumors, 2D oxygen maps were generated while the animal breathed room air or Carbogen® (95% O2/5% CO2). Carbogen® enhanced oxygen concentration within the tumor, and the pO2 histograms showed considerable heterogeneity. Clark electrode oxygen measurements on organs and tumors were in good agreement with tissue oxygen measurements done by relaxo‐oximetry. Thus, from a single spatial image data set, pO2 measurements can be done noninvasively by relaxo‐oximetry, and 3D imaging can be performed in less than 3 min. Magn Reson Med 47:1001–1008, 2002. © 2002 Wiley‐Liss, Inc.
Integral method for numerical simulation of MRI artifacts induced by metallic implants
Authors: Balac S. , Caloz G. , Cathelineau G. , Chauvel B. , de Certaines J.D. 
Published: August 2002

AbstractNumerical simulation is a valuable tool for the study of magnetic susceptibility artifacts from metallic implants. A major difficulty in the simulation lies in the computation of the magnetic field induced by the metallic implant. A new method has been designed and implemented to compute the magnetic field induced by metallic objects of arbitrary shape. The magnetic field is expressed pointwise in terms of a surface integral. Efficient quadrature schemes are proposed to evaluate this integral. Finally, the method is linked to an artifact reconstruction model to simulate the images. Magn Reson Med 45:724–727, 2001. © 2001 Wiley‐Liss, Inc.
7T vs. 4T: RF power, homogeneity, and signal‐to‐noise comparison in head images
Authors: Vaughan J.T. , Garwood M. , Collins C.M. , Liu W. , DelaBarre L. , Adriany G. , Andersen P. , Merkle H. , Goebel R. , Smith M.B. , Ugurbil K. 
Published: August 2002

AbstractSignal‐to‐noise ratio (SNR), RF field (B1), and RF power requirement for human head imaging were examined at 7T and 4T magnetic field strengths. The variation in B1 magnitude was nearly twofold higher at 7T than at 4T (∼42% compared to ∼23%). The power required for a 90° pulse in the center of the head at 7T was approximately twice that at 4T. The SNR averaged over the brain was at least 1.6 times higher at 7T compared to 4T. These experimental results were consistent with calculations performed using a human head model and Maxwell's equations. Magn Reson Med 46:24–30, 2001. © 2001 Wiley‐Liss, Inc.
Real‐time interactive coronary MRA
Authors: Nayak Krishna S. , Pauly John M. , Yang Phillip C. , Hu Bob S. , Meyer Craig H. , Nishimura Dwight G. 
Published: August 2002

AbstractAn interactive real‐time imaging system capable of rapid coronary artery imaging is described. High‐resolution spiral and circular echo planar trajectories were used to achieve 0.8 × 1.6 mm2 resolution in 135 ms (CEPI) or 1.13 × 1.13 mm2 resolution in 189 ms (spirals), over a 20‐cm FOV. Using a sliding window reconstruction, display rates of up to 37 images/sec were achieved. Initial results indicate this technique can perform as a high‐quality 2D coronary localizer and with SNR improvement may enable rapid screening of the coronary tree. Magn Reson Med 46:430–435, 2001. © 2001 Wiley‐Liss, Inc.
Development of biocompatible oxygen‐permeable films holding paramagnetic carbon particles: Evaluation of their performance and stability in EPR oximetry
Authors: He Jiang , Beghein Nelson , Ceroke Paul , Clarkson R.B. , Swartz Harold M. , Gallez Bernard 
Published: August 2002

AbstractEPR oximetry using paramagnetic particles relies on the measurement of the EPR linewidth, which is directly related to the pO2. It was previously found that some of the paramagnetic materials with optimal EPR spectroscopic properties in vitro may lose their responsiveness to oxygen in tissues (change of the calibration curve of the EPR linewidth as a function of the pO2). We hypothesized that coating paramagnetic particle materials could improve the stability of response, as well as the biocompatibility. In this study, very thin films holding paramagnetic materials were prepared with different biopolymers (cellulose acetate, cellulose triacetate, cellulose nitrate, silicone, and polyurethane) that already are accepted for clinical applications. Their performance was evaluated in EPR oximetry by measuring the stability of the calibration curves (EPR linewidth as a function of pO2) after a prolonged period in an aqueous environment
(1 week in saline) or in vivo (implantation for 3 weeks under the skin of mice). We found that one type of silicone film was able to stabilize the responsiveness of an intrinsically unstable carbon material (a wood char). Magn Reson Med 46:610–614, 2001. © 2001 Wiley‐Liss, Inc.
Modified block uniform resampling (BURS) algorithm using truncated singular value decomposition: Fast accurate gridding with noise and artifact reduction
Authors: Moriguchi Hisamoto , Duerk Jeffrey L. 
Published: August 2002

AbstractThe block uniform resampling (BURS) algorithm is a newly proposed regridding technique for nonuniformly‐sampled k‐space MRI. Even though it is a relatively computationally intensive algorithm, since it uses singular value decomposition (SVD), its procedure is simple because it requires neither a pre‐ nor a postcompensation step. Furthermore, the reconstructed image is generally of high quality since it provides accurate gridded values when the local k‐space data SNR is high. However, the BURS algorithm is sensitive to noise. Specifically, inaccurate interpolated data values are often generated in the BURS algorithm if the original k‐space data are corrupted by noise, which is virtually guaranteed to occur to some extent in MRI. As a result, the reconstructed image quality is degraded despite excellent performance under ideal conditions. In this article, a method is presented which avoids inaccurate interpolated k‐space data values from noisy sampled data with the BURS algorithm. The newly proposed technique simply truncates a series of singular values after the SVD is performed. This reduces the computational demand when compared with the BURS algorithm, avoids amplification of noise resulting from small singular values, and leads to image SNR improvements over the original BURS algorithm. Magn Reson Med 46:1189–1201, 2001. © 2001 Wiley‐Liss, Inc.