bluuebunny/crossref_metadata_2025_split huggingface dataset:
The spatial and mechanical challenges of female meiosis
Authors: Evans Janice P. , Robinson Douglas N. 
Published: June 2011

AbstractRecent work shows that cytokinesis and other cellular morphogenesis events are tuned by an interplay among biochemical signals, cell shape, and cellular mechanics. In cytokinesis, this includes cross‐talk between the cortical cytoskeleton and the mitotic spindle in coordination with cell cycle control, resulting in characteristic changes in cellular morphology and mechanics through metaphase and cytokinesis. The changes in cellular mechanics affect not just overall cell shape, but also mitotic spindle morphology and function. This review will address how these principles apply to oocytes undergoing the asymmetric cell divisions of meiosis I and II. The biochemical signals that regulate cell cycle timing during meiotic maturation and egg activation are crucial for temporal control of meiosis. Spatial control of the meiotic divisions is also important, ensuring that the chromosomes are segregated evenly and that meiotic division is clearly asymmetric, yielding two daughter cells – oocyte and polar body – with enormous volume differences. In contrast to mitotic cells, the oocyte does not undergo overt changes in cell shape with its progression through meiosis, but instead maintains a relatively round morphology with the exception of very localized changes at the time of polar body emission. Placement of the metaphase‐I and ‐II spindles at the oocyte periphery is clearly important for normal polar body emission, although this is likely not the only control element. Here, consideration is given to how cellular mechanics could contribute to successful mammalian female meiosis, ultimately affecting egg quality and competence to form a healthy embryo. Mol. Reprod. Dev. 78:769–777, 2011. © 2011 Wiley Periodicals, Inc.
Parallel imaging with nonlinear reconstruction using variational penalties
Authors: Knoll Florian , Clason Christian , Bredies Kristian , Uecker Martin , Stollberger Rudolf 
Published: June 2011

AbstractA new approach based on nonlinear inversion for autocalibrated parallel imaging with arbitrary sampling patterns is presented. By extending the iteratively regularized Gauss–Newton method with variational penalties, the improved reconstruction quality obtained from joint estimation of image and coil sensitivities is combined with the superior noise suppression of total variation and total generalized variation regularization. In addition, the proposed approach can lead to enhanced removal of sampling artifacts arising from pseudorandom and radial sampling patterns. This is demonstrated for phantom and in vivo measurements. Magn Reson Med 67:34–41, 2012. © 2011 Wiley Periodicals, Inc.
Addressing phase errors in fat‐water imaging using a mixed magnitude/complex fitting method
Authors: Hernando D. , Hines C. D. G. , Yu H. , Reeder S.B. 
Published: June 2011

AbstractAccurate, noninvasive measurements of liver fat content are needed for the early diagnosis and quantitative staging of nonalcoholic fatty liver disease. Chemical shift‐based fat quantification methods acquire images at multiple echo times using a multiecho spoiled gradient echo sequence, and provide fat fraction measurements through postprocessing. However, phase errors, such as those caused by eddy currents, can adversely affect fat quantification. These phase errors are typically most significant at the first echo of the echo train, and introduce bias in complex‐based fat quantification techniques. These errors can be overcome using a magnitude‐based technique (where the phase of all echoes is discarded), but at the cost of significantly degraded signal‐to‐noise ratio, particularly for certain choices of echo time combinations. In this work, we develop a reconstruction method that overcomes these phase errors without the signal‐to‐noise ratio penalty incurred by magnitude fitting. This method discards the phase of the first echo (which is often corrupted) while maintaining the phase of the remaining echoes (where phase is unaltered). We test the proposed method on 104 patient liver datasets (from 52 patients, each scanned twice), where the fat fraction measurements are compared to coregistered spectroscopy measurements. We demonstrate that mixed fitting is able to provide accurate fat fraction measurements with high signal‐to‐noise ratio and low bias over a wide choice of echo combinations. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Localized blood flow imaging using quantitative flow‐enhanced signal intensity
Authors: Ouyang Cheng , Sutton Bradley P. 
Published: June 2011

AbstractFlow‐enhanced signal intensity (FENSI) was previously introduced as a novel functional imaging method for measuring changes in localized blood flow in response to a stimulus. However, FENSI was limited to a qualitative functional MRI tool, due to magnetization transfer effects and different tagging plane profiles between tag and control images. In this work, a revised FENSI acquisition is proposed to enable quantitative imaging, which is capable of providing absolute localized blood flow maps free from magnetization transfer and slice profile errors. The feasibility and accuracy of measuring microvascular (arteriole, capillary, and venule) blood flow by using quantitative FENSI was validated by our phantom studies. Additionally, localized cerebral blood flow, 366 ± 45 μL/min/cm2 in gray matter and 153 ± 23 μL/min/cm2 in white matter, was measured in healthy subjects during resting state, whereas a flow change of 73 ± 13% was detected during a visual task. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Lung morphometry with hyperpolarized 129Xe: Theoretical background
Authors: Sukstanskii A. L. , Yablonskiy D. A. 
Published: June 2011

AbstractThe 3He lung morphometry technique, based on MRI measurements of hyperpolarized 3He gas diffusion in lung airspaces, provides unique information on the lung microstructure at the alveolar level. In vivo 3D tomographic images of standard morphological parameters (airspace chord length, lung parenchyma surface‐to‐volume ratio, and number of alveoli per unit volume) can be generated from a rather short (several seconds) MRI scan. The technique is based on a theory of gas diffusion in lung acinar airways and experimental measurements of diffusion‐attenuated MRI signal. The present work aims at developing the theoretical background of a similar technique based on hyperpolarized 129Xe gas. As the diffusion coefficient and gyromagnetic ratio of 129Xe gas are substantially different from those of 3He gas, the specific details of the theory and experimental measurements with 129Xe should be amended. We establish phenomenological relationships between acinar airway geometrical parameters and the diffusion‐attenuated MR signal for human and small animal lungs, both normal lungs and lungs with mild emphysema. Optimal diffusion times are shown to be about 5 ms for human and 1.3 ms for small animals. The expected uncertainties in measuring main morphometrical parameters of the lungs are estimated in the framework of Bayesian probability theory. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Comparison of two methods for measuring the pubococcygeal line from sagittal‐plane magnetic resonance imaging
Authors: Madill Stéphanie , Tang An , Pontbriand‐Drolet Stéphanie , Dumoulin Chantal 
Published: June 2011

AbstractAimsThe pubococcygeal line (PCL) is an important reference line for determining measures of pelvic organ support on sagittal‐plane magnetic resonance imaging (MRI); however, there is no consensus on where to place the posterior point of the PCL. As coccyx movement produced during pelvic floor muscle (PFM) contractions may affect other measures, optimal placement of the posterior point is important. This study compared two methods for measuring the PCL, with different posterior points, on T2‐weighted sagittal MRI to determine the effect of coccygeal movement on measures of pelvic organ support in older women.MethodsMRI of the pelvis was performed in the midsagittal plane, at rest and during PFM contractions, on 47 community‐dwelling women 60 and over. The first PCL was measured to the tip of the coccyx (PCLtip) and the second to the sacrococcygeal joint (PCLjnt). Four measures of pelvic organ support were made using each PCL as the reference line: urethrovesical junction height, uterovaginal junction height, M‐line and levator plate angle.ResultsDuring the PFM contraction the PCLtip shortened and lifted (P < 0.001); the PCLjnt did not change (P > 0.05). The changes in the four measures of pelvic organ support were smaller when measured relative to the PCLtip as compared to those to the PCLjnt (P < 0.001).ConclusionsCoccyx movement affected the length and position of the PCLtip, which resulted in underestimates of the pelvic‐organ lift produced by the PFM contraction. Therefore, we recommend that the PCL be measured to the sacrococcygeal joint and not to the tip of the coccyx. Neurourol. Urodynam. Neurourol. Urodynam. 30: 1613–1619, 2011. © 2011 Wiley Periodicals, Inc.
Developmental and spinal cord injury‐induced changes in nitric oxide‐mediated inhibition in rat urinary bladder
Authors: Artim Debra E. , Kullmann F. Aura , Daugherty Stephanie L. , Bupp Evan , Edwards Cassandra L. , de Groat William C. 
Published: June 2011

AbstractAimsDuring postnatal development large amplitude spontaneous activity of the neonatal rat bladder changes to a low amplitude adult pattern of activity that leads to improved storage function. Previously, we have shown that spontaneous activity in neonatal rat bladder strips is inhibited by activation of the nitric oxide (NO)–cGMP signaling pathway. In the present experiments we determined if this inhibitory pathway is altered during postnatal development or spinal cord injury.MethodsBaseline tone and amplitude and frequency of spontaneous contractions were measured in bladder strips from male or female neonatal (days 10–21), juvenile (days 24–39) and adult female spinal cord intact or chronic spinal cord injured Sprague–Dawley rats.ResultsThe inhibitory effects of an NO donor (SNAP) and a PDE‐5 inhibitor (zaprinast) on spontaneous activity of bladder strips decreased during postnatal development, while an inhibitory effect of 8‐bromo‐cGMP, which was blocked by a protein kinase G inhibitor, was detected at all ages tested. However, the effect of NO–cGMP signaling to reduce baseline tone emerged during postnatal development. The inhibition induced by the NO donor was blocked by an inhibitor of soluble guanylyl cyclase (sGC). Chronic spinal cord injury (cSCI), which causes the re‐emergence of a neonatal‐like pattern of spontaneous activity, did not restore sensitivity to NO‐mediated inhibition in adult rat bladders.ConclusionsThese data indicate that while cGMP signaling inhibits activity in young and adult bladders as well as after cSCI, there is a developmental decrease in the sensitivity of bladder to NO‐mediated inhibition. Neurourol. Urodynam. Neurourol. Urodynam. 30: 1666–1674, 2011. © 2011 Wiley Periodicals, Inc.
Subadult Age‐at‐Death Estimation From the Human Calcaneus
Authors: Passalacqua Nicholas V. 
Published: June 2011

ABSTRACTThe estimation of age from subadult skeletal remains relies on the measurement of bones, which when unavailable or damaged hampers the ability to generate a reliable age estimate. The goal of this project was to demonstrate two methods for estimating age at death from the developing human calcaneus. These methods are generated from a sample of 32 European American and African American males and females with ages ranging from 1 to 19 years from the Hamann–Todd Collection. The first method was based on linear regression from two standard measurements of the calcaneus (maximum length and middle breadth); the second was based on transition analysis of fusion states of the calcaneal epiphysis. Results suggest that both methods perform well in estimating subadult age at death. Additional testing with larger contemporary samples would likely increase the accuracy of both methods. Copyright © 2011 John Wiley & Sons, Ltd.
Alteration of Time Perception in Young and Elderly People during Jigsaw Puzzle Tasks with Different Complexities
Authors: Iwamoto Yuko , Hoshiyama Minoru 
Published: July 2011

AbstractWe investigated the relationship between time perception during tasks and subjective feelings in young and elderly people. Simple and complex jigsaw puzzles were given to healthy young and elderly subjects. The subjects were asked to estimate the time they had taken to complete the tasks after performing them. The ratio of the subjective to actual duration of time, the duration judgment ratio (DJR), and the relationship between the DJR and the subjective feelings during the tasks were analysed. The elderly group required a significantly longer time than the younger group for both tasks, and both elderly and young subjects estimated a longer time than the actual time to complete the tasks. The effect of the tasks on the DJR was significant, and the value was higher for the 24‐piece than 54‐piece task in both groups. The DJR was smaller in subjects with “much interest” than in those with “little interest” in the 24‐piece task, but there was no difference in the 54‐piece task. The results indicate that time perception was modulated by subjective feelings during the task, as well as by the age and task complexity. Because the goal and the result of the task may modulate time perception during it, time perception while actually performing the task may differ from that after completing it. Copyright © 2011 John Wiley & Sons, Ltd.
PLATEAUS NOT SUMMITS: REFORMING PUBLIC FINANCIAL MANAGEMENT IN AFRICA
Authors: Peterson Stephen Bovard 
Published: June 2011

SUMMARYSuccessful public sector reform is rare in Africa. Over 12 years, Ethiopia transformed its public financial management (PFM) to international standards and now has the third best system in Africa that is managing the largest aid flows to the continent. This article presents a framework for understanding PFM reform based on the Ethiopian experience. Reforms succeed when they are aligned with the four drivers of public sector reform: context, ownership, purpose, and strategy. PFM is a core function of the state and its sovereignty, and it is not an appropriate arena for foreign aid intervention—governments must fully own it, which was a key to the success of Ethiopia's reform. The purpose of PFM reform should be building stable and sustainable “plateaus” of PFM that are appropriate to the local context, and they should not be about risky and irrelevant “summits” of international best practice. Plateaus, not summits, are needed in Africa. Finally, a strategy of reform has four tasks: recognize, improve, change, and sustain. Ethiopia succeeded because it implemented a recognize–improve–sustain strategy to support the government policy of rapid decentralization. All too often, much of the PFM reform in Africa is about the change task and climbing financial summits. Copyright © 2011 John Wiley & Sons, Ltd.
Clonal architecture of human prostatic epithelium in benign and malignant conditions
Authors: Gaisa Nadine T , Graham Trevor A , McDonald Stuart AC , Poulsom Richard , Heidenreich Axel , Jakse Gerhard , Knuechel Ruth , Wright Nicholas A 
Published: July 2011

AbstractThe location of stem cells in the epithelium of the prostatic acinus remains uncertain, as does the cellular origin of prostatic neoplasia. Here, we apply lineage tracing to visualize the clonal progeny of stem cells in benign and malignant human prostates and understand the clonal architecture of this epithelium. Cells deficient for the mitochondrially‐encoded enzyme cytochrome c oxidase (CCO) were identified in 27 frozen prostatectomy specimens using dual colour enzyme histochemistry and individual CCO‐normal and ‐deficient cell areas were laser‐capture microdissected. PCR‐sequencing of the entire mitochondrial genome (mtDNA) of cells from CCO‐deficient areas found to share mtDNA mutations not present in adjacent CCO‐normal cells, thus proving a clonal origin. Immunohistochemistry was performed to visualize the three cell lineages normally present in the prostatic epithelium. Entire CCO‐deficient acini, and part‐deficient acini were found. Deficient patches spanned either basal or luminal cells, but sometimes also both epithelial cell types in normal, hyperplastic or atrophic epithelium, and prostatic intraepithelial neoplasia (PIN). Patches comprising both PIN and invasive cancer were observed. Each cell area within a CCO‐deficient patch contained an identical mtDNA mutation, defining the patch as a clonal unit. CCO‐deficient patches in benign epithelium contained basal, luminal and endocrine cells, demonstrating multilineage differentiation and therefore the presence of a stem cell. Our results demonstrate that the normal, atrophic, hypertrophic and atypical (PIN) epithelium of human prostate contains stem cell‐derived clonal units that actively replenish the epithelium during ageing. These deficient areas usually included the basal compartment indicating the basal layer as the location of the stem cell. Importantly, single clonal units comprised both PIN and invasive cancer, supporting PIN as the pre‐invasive lesion for prostate cancer. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Clinical predictors of high risk histopathology in retinoblastoma
Authors: Kashyap Seema , Meel Rachna , Pushker Neelam , Sen Seema , Bakhshi Sameer , Sreenivas Vishnubhatla , Sethi Sumita , Chawla Bhavna , Ghose Supriyo 
Published: June 2011

AbstractBackgroundPrevious studies show that clinical features at presentation, in retinoblastoma patients, like glaucoma and neovascularization of iris are associated with a higher incidence of high risk histopathology findings (HRF) in enucleated eyes. Herein, we analyze association between clinical features at time of enucleation and occurrence of HRF including invasion of anterior chamber, iris, ciliary body, choroid (massive), sclera, extrascleral tissue, optic nerve beyond lamina cribrosa, and optic nerve cut end, in a large series of eyes enucleated for retinoblastoma.ProcedureWe retrospectively studied demographic, clinical, and histopathology findings in all retinoblastoma patients who underwent primary enucleation at our center, over a 5 years duration. Statistical analysis was done to find any association between clinical features at presentation and the presence of HRF.ResultsThree hundred twenty‐six eyes were studied. Median age of presentation was 2 years. Glaucoma was the most common clinical finding at presentation apart from leucocoria. Out of 326 enucleated eyes, 28 (8.6%) had extrascleral and/or optic nerve transection invasion. Among remaining 298 eyes, with completely resected tumor, 115 (38.6%) had massive choroidal invasion, 54 (17%) had retrolaminar optic nerve invasion, and 24 (7%), 29 (9%), and 23(7%) had anterior chamber, iris, and ciliary body invasion, respectively. Age more than 2 years, lag period more than 3 months, hyphema, pseudohypopyon, staphyloma, and orbital cellulitis were associated with occurrence of three or more HRF on univariate analysis.ConclusionsClinical variables including older age, longer lag period, hyphema, pseudohypopyon, staphyloma, and orbital cellulitis were strongly associated with occurrence of HRF in this study. Pediatr Blood Cancer 2012; 58: 356–361. © 2011 Wiley Periodicals, Inc.
Effect of cord puncture site in cordocentesis at mid‐pregnancy on pregnancy outcomes
Authors: Tangshewinsirikul Chayada , Wanapirak Chanane , Piyamongkol Wirawit , Sirichotiyakul Supatra , Tongsong Theera 
Published: June 2011

AbstractObjectivesTo compare the procedure and pregnancy outcomes of pregnancies undergoing cordocentesis between a group of cord insertion puncture and that of free loop puncture.Materials and MethodsPregnancies undergoing cordocenteses meeting the following inclusion criteria were recruited: (1) singleton pregnancies at gestational ages of 18–22 weeks; (2) no fetal abnormalities; (3) the procedures performed by experienced operators; and (4) the procedures of no placenta penetration. The recruited cases were classified into two groups: a group of cordocenteses with puncture site at placental cord insertion (Group 1) and those with puncture site at cord free loop (Group 2). The primary outcomes to be compared were rates of fetal loss, newborns with low birth weight and preterm birth. The secondary outcomes included a rate of successful procedures, umbilical cord bleeding, fetal bradycardia, maternal blood contamination, and duration of the procedure time.ResultsOf 6147 cordocenteses recruited, 2214 met inclusion criteria. The mean duration to complete the procedure in Group 1 was significantly shorter than that in Group 2 (4.5 ± 5.4 vs 6.7 ± 8.5 min, Student's t‐test; p = 0.001). The mean birth weight and gestational age at delivery were comparable between the two groups. No significant differences between the two groups were seen in rates of fetal loss, low birth weight, preterm birth, successful procedures, umbilical cord bleeding, or fetal bradycardia. However, the rate of maternal blood contamination was significantly higher in the group of puncture at the cord insertion site.ConclusionOf cordocenteses performed based on accessibility and quality of visualization, cord insertion puncture may cause more maternal blood contamination but free loop puncture may be associated with more difficult procedures, while the safety was comparable. Copyright © 2011 John Wiley & Sons, Ltd.
Holoprosencephaly at prenatal diagnosis: analysis of 28 cases regarding etiopathogenic diagnoses
Authors: Petracchi F. , Crespo L. , Michia C. , Igarzabal L. , Gadow E. 
Published: June 2011

AbstractObjectiveTo assess the likelihood of finding an etiopathogenic cause in an ultrasonographic prenatal diagnosis of holoprosencephaly.Materials and MethodsFrom January 1996 to June 2010, 13 883 prenatal diagnoses through chorionic villus sampling or amniocentesis were made. Every fetus with holoprosencephaly at ultrasound was evaluated. Gestational age, additional ultrasound findings, and fetal karyotype were recorded. Molecular diagnosis and parental karyotype were studied, if relevant.ResultsTwenty‐eight fetuses were diagnosed with holoprosencephaly (0.20%). All cases had additional ultrasound findings (100%). A definitive etiology was found in 23 cases (82.14%): karyotype was abnormal in 19 (67.9%) and normal in 8 (28.5%) cases. In the normal karyotype group, although molecular testing was performed in a few cases, one mutation of gene SIX 3 was diagnosed, one diagnosis of dysgnathia complex was made, and two fetuses presented Smith–Lemli–Opitz syndrome. No etiopathogenic diagnosis was made in five fetuses.ConclusionsOur results showed that a definitive etiology can be established in most cases of prenatal holoprosencephaly. Chromosomal anomalies were the most frequent finding. However, in euploid fetuses, molecular diagnosis is worthwhile, as different genes with different inheritance patterns may be responsible for this malformation. Thorough evaluation proved beneficial for assessing more accurate prognosis and recurrence risks. Copyright © 2011 John Wiley & Sons, Ltd.