bluuebunny/crossref_metadata_2025_split huggingface dataset:
Local circuitry involving parvalbumin‐positive basket cells in the CA2 region of the hippocampus
Authors: Mercer Audrey , Eastlake Karen , Trigg Hayley L. , Thomson Alex M. 
Published: September 2010

AbstractThere is a growing recognition that the CA2 region of the hippocampus has its own distinctive properties, inputs, and pathologies. The dendritic and axonal patterns of some interneurons in this region are also strikingly different from those described previously in CA1 and CA3. The local circuitry in this region, however, had yet to be studied in detail. Accordingly, using dual intracellular recordings and biocytin‐filling, excitatory and inhibitory connections involving CA2 parvalbumin‐positive basket cells were characterized for the first time. CA2 basket cells targeted neighboring pyramidal cells and received excitatory inputs from them. CA2 basket cells that resembled those in CA1 with a fast spiking behavior and dendritic tree confined to the region of origin received depressing excitatory postsynaptic potentials (EPSPs). In contrast, unlike CA1 basket cells but like CA1 Oriens‐Lacunosum Moleculare (OLM) cells, the majority of CA2 basket cells had horizontally oriented dendrites in Stratum Oriens (SO), which extended into all three CA subfields, had an adapting firing pattern, presented a “sag” in their voltage responses to hyperpolarizing current injection, and received facilitating EPSPs. The expression of Ih did not influence the EPSP time courses and paired pulse ratios (PPR). Estimates of the probability of release (p) for the depressing and facilitating EPSPs were correlated with the PPR. Connections with low probabilities of release had higher PPR. Quantal amplitude (q) for the facilitating connections was larger than q at depressing inputs onto fast spiking basket cells. © 2010 Wiley Periodicals, Inc., Inc.
Astrocyte calcium signals at Schaffer collateral to CA1 pyramidal cell synapses correlate with the number of activated synapses but not with synaptic strength
Authors: Honsek Silke D. , Walz Corinna , Kafitz Karl W. , Rose Christine R. 
Published: September 2010

AbstractGlial cells respond to neuronal activity by transient increases in their intracellular calcium concentration. At hippocampal Schaffer collateral to CA1 pyramidal cell synapses, such activity‐induced astrocyte calcium transients modulate neuronal excitability, synaptic activity, and LTP induction threshold by calcium‐dependent release of gliotransmitters. Despite a significant role of astrocyte calcium signaling in plasticity of these synapses, little is known about activity‐dependent changes of astrocyte calcium signaling itself. In this study, we analyzed calcium transients in identified astrocytes and NG2‐cells located in the stratum radiatum in response to different intensities and patterns of Schaffer collateral stimulation. To this end, we employed multiphoton calcium imaging with the low‐affinity indicator dye Fluo‐5F in glial cells, combined with extracellular field potential recordings to monitor postsynaptic responses to the afferent stimulation. Our results confirm that somata and processes of astrocytes, but not of NG2‐cells, exhibit intrinsic calcium signaling independent of evoked neuronal activity. Moderate stimulation of Schaffer collaterals (three pulses at 50 Hz) induced calcium transients in astrocytes and NG2‐cells. Astrocyte calcium transients upon this three‐pulse stimulation could be evoked repetitively, increased in amplitude with increasing stimulation intensity and were dependent on activation of metabotropic glutamate receptors. Activity‐induced transients in NG2‐cells, in contrast, showed a rapid run‐down upon repeated three‐pulse stimulation. Theta burst stimulation and stimulation for 5 min at 1 Hz induced synaptic potentiation and depression, respectively, as revealed by a lasting increase or decrease in population spike amplitudes upon three‐pulse stimulation. Synaptic plasticity was, however, not accompanied by corresponding alterations in the amplitude of astrocyte calcium signals. Taken together, our results suggest that the amplitude of astrocyte calcium signals reflects the number of activated synapses but does not correlate with the degree of synaptic potentiation or depression at Schaffer collateral to CA1 pyramidal cell synapses. © 2010 Wiley Periodicals, Inc., Inc.
Neurokinin2‐R in medial septum regulate hippocampal and amygdalar ACh release induced by intraseptal application of neurokinins A and B
Authors: Schäble Sandra , Huston Joseph P. , de Souza Silva Maria A. 
Published: September 2010

AbstractThe neurokinin receptors (NK‐R), NK2‐ and NK3‐R, have been implicated in behavioral processes, but apparently in opposite ways: while NK2‐R agonism disrupts memory and has anxiogenic‐like action, NK3‐R agonists facilitate memory and display anxiolytic‐like effects. Systemic application of NK2‐R antagonists block the release of acetylcholine (ACh) in the hippocampus, which is induced by intraseptal administration of the NK2‐R ligand, neurokinin A (NKA). We investigated the effects of medial septal injection of NKA and a preferred ligand of NK3‐R, neurokinin B (NKB), on the activity of cholinergic neurons of the basal forebrain and assessed the role of the medial septal NK2‐R in the control of extracellular ACh levels in cholinergic projection areas. ACh was dialysed in the frontal cortex, amygdala and hippocampus of anesthetized animals and was analysed by HPLC‐EC. ACh levels in hippocampus and amygdala, but not in frontal cortex were increased after intraseptal injection of either NKA or NKB (0.1, 1, 10 μM). Application of the nonpeptidic NK2‐R antagonist, saredutant SR48968 (1, 10, 100 pM), followed by NKA (1 μM) or NKB (10 μM) injection into the medial septum, blocked the ACh increase in hippocampus and amygdala. These results indicate that medial septal NK2‐R have an important role in mediating ACh release, for one, via the septal‐hippocampal cholinergic projection and, secondly, via direct or indirect route to the amygdala, but not frontal cortex. They also support the hypothesis that hippocampal cholinergic neurotransmission controls amygdala function suggesting that this interaction is regulated via NK2‐R in the medial septum. © 2010 Wiley Periodicals, Inc.
Building and remodeling synapses
Authors: Benson Deanna L. , Huntley George W. 
Published: September 2010

AbstractSynaptic junctions are generated by adhesion proteins that bridge the synaptic cleft to firmly anchor pre‐ and postsynaptic membranes. Several cell adhesion molecule (CAM) families localize to synapses, but it is not yet completely understood how each synaptic CAM family contributes to synapse formation and/or structure, and whether or how smaller groups of CAMs serve as minimal, functionally cooperative adhesive units upon which structure is based. Synapse structure and function evolve over the course of development, and in mature animals, synapses are composed of a greater number of proteins, surrounded by a stabilizing extracellular matrix, and often contacted by astrocytic processes. Thus, in mature networks undergoing plasticity, persistent changes in synapse strength, morphology, or number must be accompanied by selective and regulated remodeling of the neuropil. Recent work indicates that regulated, extracellular proteolysis may be essential for this, and rather than simply acting permissively to enable synapse plasticity, is more likely playing a proactive role in driving coordinated synaptic structural and functional modifications that underlie persistent changes in network activity. © 2010 Wiley Periodicals, Inc.
Changing the criteria for old/new recognition judgments can modulate activity in the anterior hippocampus
Authors: Hashimoto Ryusaku , Abe Nobuhito , Ueno Aya , Fujii Toshikatsu , Takahashi Shoki , Mori Etsuro 
Published: September 2010

AbstractNumerous functional magnetic resonance imaging (fMRI) studies have reported that the medial temporal lobe (MTL) is activated to a greater extent when subjects encounter novel items as compared with familiar ones. However, it remains unclear whether the novelty signals in the MTL are modulated by the criteria for old/new recognition judgments. In this study, we used fMRI to test our hypothesis that when subjects encounter items similar to previously encountered ones, the novelty signals in the MTL will differ depending on whether the subjects focus on the perceptual features or the semantic aspects of the items. The subjects studied a series of photographs and were later asked to make a recognition judgment of (a) Same items (items identical to those seen during encoding), (b) Similar items (items similar to but not identical to those seen during encoding), and (c) New items (unstudied items) in two types of tasks: Perceptual and Semantic. The subjects judged whether the items were perceptually identical to those seen during encoding in the Perceptual task and whether the items were semantically identical to those seen during encoding in the Semantic task. The left anterior hippocampus was activated when subjects were presented with New items relative to Same items in both tasks. In addition, the hippocampal activity in response to the Similar items was increased only in the Perceptual, but not the Semantic task. Our results indicate that the novelty signals in the hippocampus can be modulated by criteria for old/new recognition judgments. © 2010 Wiley Periodicals, Inc.
Conquering cancer through discovery research
Authors: Cho William C. S. 
Published: September 2010

AbstractCancer is a leading cause of death worldwide. Cancer research improves our understanding of cancer biology, which leads to the discoveries of novel detection approaches and effective therapies for cancer. Translational cancer medicine changes essential science breakthroughs to the practice of medicine and uses clinical result to supply back into basic research. This article covers some studies in the field of translational cancer medicine including the identification of 319 driver genes and the 12 core cancer pathways, the use of MammaPrint in breast cancer, the development of OncoMap, the progress in genome‐wide association studies, as well as the generation of microRNA networks in cancer and leukemia. Apart from cancer genome, cancer stem cells, immune and tumor microenvironment are also discussed. In addition, some innovations in translational cancer medicine are introduced. A number of targeted agents have been developed, such as the histone deacetylases inhibitors, poly(ADP‐ribose) polymerase inhibitors, anti‐mammalian target of rapamycin agents, and PI3K pathway inhibitors. There are also reports of the results from some important clinical trials, including the STAR P‐2 trial, NeoBIG program, and BATTLE trial. This review focuses on discussions that emphasize the marriage between curiosity‐driven basic research and patient care‐focused clinical investigations. With highlights on the most up‐to‐date molecular, cellular, clinical, and therapeutic cancer research findings, this article tends to provide a wealth of insights into better understanding of the complexity of cancer. © 2010 IUBMB IUBMB Life, 62(9): 655–659, 2010
Amino acid ingestion and glucose metabolism—A review
Authors: Gannon Mary C. , Nuttall Frank Q. 
Published: September 2010

AbstractInterest in the effect of proteins or amino acids on glucose metabolism dates back at least a century, largely because it was demonstrated that the amino acids from ingested protein could be converted into glucose. Indeed, these observations influenced the dietary information provided to people with diabetes. Subsequently it was shown that ingested protein did not raise the blood glucose concentration. It also was shown that proteins could stimulate a rise in insulin and glucagon but the response to various proteins was different. In addition, it was shown that individual amino acids also could stimulate a rise in insulin and in glucagon concentrations. When individual amino acids are ingested by normal subjects, there is an ordering of the insulin and glucagon responses. However, the order is not the same for insulin and glucagon. In addition, the metabolic response cannot be predicted based on the functional groups of the amino acids. Thus, empirical prediction of the metabolic response to ingested single amino acids is not possible. © 2010 IUBMB IUBMB Life, 62(9): 660–668, 2010
3 Tesla and 7 Tesla MRI of multiple sclerosis cortical lesions
Authors: Tallantyre Emma C. , Morgan Paul S. , Dixon Jennifer E. , Al‐Radaideh Ali , Brookes Matthew J. , Morris Peter G. , Evangelou Nikos 
Published: September 2010

AbstractCortical lesions are prevalent in multiple sclerosis but are poorly detected using MRI. The double inversion recovery (DIR) sequence is increasingly used to explore the clinical relevance of cortical demyelination. Here we evaluate the agreement between imaging sequences at 3 Tesla (T) and 7T for the presence and appearance of individual multiple sclerosis cortical lesions. Eleven patients with demyelinating disease and eight healthy volunteers underwent MR imaging at 3T (fluid attenuated inversion recovery [FLAIR], DIR, and T1‐weighted magnetization prepared rapid acquisition gradient echo [MP‐RAGE] sequences) and 7T (T1‐weighted MP‐RAGE). There was good agreement between images for the presence of mixed cortical lesions (involving both gray and white matter). However, agreement between imaging sequences was less good for purely intracortical lesions. Even after retrospective analysis, 25% of cortical lesions could only be visualized on a single MRI sequence. Several DIR hyperintensities thought to represent cortical lesions were found to correspond to signal arising from extracortical blood vessels. High‐resolution 7T imaging appeared useful for confidently classifying the location of lesions in relation to the cortical/subcortical boundary. We conclude that DIR, FLAIR, and MP‐RAGE imaging sequences appear to provide complementary information during the detection of multiple sclerosis cortical lesions. High resolution 7T imaging may facilitate anatomical localization of lesions in relation to the cortical boundary. J. Magn. Reson. Imaging 2010;32:971–977. © 2010 Wiley‐Liss, Inc.
T1ρ and T2 quantitative magnetic resonance imaging analysis of cartilage regeneration following microfracture and mosaicplasty cartilage resurfacing procedures
Authors: Holtzman Daniel J , Theologis Alexander A , Carballido‐Gamio Julio , Majumdar Sharmila , Li Xiaojuan , Benjamin C. 
Published: September 2010

AbstractPurposeTo examine T1ρ (T1rho) and T2 quantitative magnetic resonance imaging (MRI) in evaluating cartilage regeneration following microfracture (MFx) and mosaicplasty (MOS) cartilage resurfacing procedures.Materials and MethodsEighteen patients underwent MFx and eight patients underwent MOS to treat symptomatic focal cartilage defects. Quantitative T1ρ and T2 maps were acquired at 3–6 months and 1 year after surgery. The area of resurfacing was identified, and T1ρ and T2 values for the regenerated tissue (RT) and normal cartilage (NC) were acquired. RT/NC ratios were calculated to standardize absolute T1ρ and T2 values. Data were prospective, cross‐sectional, and nonrandomized.ResultsT1ρ and T2 showed good reanalysis reproducibility for RT and NC. Significant differences between RT and NC were present following MFx at 3–6 months for T1ρ and T2 values as well as following MOS at 3–6 months and 1 year for T1ρ values. Following MFx, the T2 RT/NC ratio was significantly different between 3–6 months and 1 year (P = 0.02), while the T1ρ RT/NC ratio approached significance (P = 0.07). Following MOS, the T1ρ and T2 RT/NC ratios were not significantly different between the two timepoints.ConclusionT1ρ and T2 MRI are complementary and reproducible methods for quantitatively and noninvasively monitoring regeneration of RT following MFx and MOS. J. Magn. Reson. Imaging 2010;32:914–923. © 2010 Wiley‐Liss, Inc.
Quantitative cerebral MR perfusion imaging: Preliminary results in stroke
Authors: Shah Maulin K. , Shin Wanyong , Parikh Vishal S. , Ragin Ann , Mouannes Jessy , Bernstein Richard A. , Walker Matthew T. , Bhatt Hem , Carroll Timothy J. 
Published: September 2010

AbstractPurposeTo evaluate quantitative cerebral blood flow (qCBF) with traditional time‐based measurements or metrics of cerebral perfusion: time to peak (Tmax) and mean transit time (MTT) in stroke patients.Materials and MethodsNine ischemic stroke patients (four male, five female, 63 ± 16 years old) were included in the study which was Health Insurance Portability and Accountability Act compliant and institutional review board approved. Cerebral perfusion was quantified using the Bookend method. Mean values of qCBF, Tmax, and MTT were determined in regions of interest (ROIs). ROIs were drawn on diffusion weighted images in diffusion positive, critically ischemic (CI), in ipsilateral normal region immediately surrounding the critically ischemic region, the presumed penumbra (PP), and in contralateral diffusion negative control, presumed normal region (PN) of gray and white matter separately (GM and WM).ResultsIn both GM and WM, qCBF measures distinguished the studied brain regions with the most markedly reduced values in regions corresponding to extent of likely ischemic injury. In planned comparisons, only qCBF measurements differed significantly between CI and PP tissues. ROC analysis supported the utility of qCBF for discriminating brain regions differing in the likely extent of ischemic injury (CI and PN regions – qCBF: area under the curve [AUC] = 0.96, Tmax: AUC = 0.96, MTT: AUC = 0.72). Importantly, qCBF afforded the best discrimination of CI and PP regions (qCBF: AUC = 0.82, Tmax: AUC = 0.65, MTT: AUC = 0.52).ConclusionThis initial evaluation indicates that quantitative MRI perfusion is feasible in ischemic stroke patients. qCBF derived with this strategy provide enhanced discrimination of CI and PP compared to time‐based imaging metrics. This approach merits investigation in larger clinical studies. J. Magn. Reson. Imaging 2010;32:796–802. © 2010 Wiley‐Liss, Inc.
Predicting survival in glioblastomas using diffusion tensor imaging metrics
Authors: Saksena Sona , Jain Rajan , Narang Jayant , Scarpace Lisa , Schultz Lonni R. , Lehman Norman L. , Hearshen David , Patel Suresh C. , Mikkelsen Tom 
Published: September 2010

AbstractPurposeTo retrospectively correlate various diffusion tensor imaging (DTI) metrics in patients with glioblastoma multiforme (GBM) with patient survival analysis and also degree of tumor proliferation index determined histologically.Materials and MethodsThirty‐four patients with histologically confirmed treatment naive GBMs underwent DTI on a 3.0 Tesla (T) scanner. Region‐of‐interest was placed on the whole lesion including the enhancing as well as nonenhancing component of the lesion to determine the various DTI metrics. Kaplan‐Meier estimates and Cox proportional hazards regression methods were used to assess the relationship of DTI metrics (minimum and mean values) and Ki‐67 with progression free survival (PFS). To study the relationship between DTI metrics and Ki‐67, Pearson's correlation coefficient was computed.ResultsUnivariate analysis showed that patients with fractional anisotropy (FA)mean ≤ 0.2, apparent diffusion coefficient (ADC)min ≤ 0.6, planar anisotropy (CP)min ≤ 0.002, spherical anisotropy (CS)mean > 0.68 and Ki‐67 > 0.3 had lower PFS rate. The multivariate analysis demonstrated that only CPmin was the best predictor of survival in these patients, after adjusting for age, Karnofsky performance scale and extent of resection. No significant correlation between DTI metrics and Ki‐67 were observed.ConclusionDTI metrics can be used as a sensitive and early indicator for PFS in patients with glioblastomas. This could be useful for treatment planning as high‐grade gliomas with lower ADCmin, FAmean, CPmin, and higher CSmean values may be treated more aggressively. J. Magn. Reson. Imaging 2010;32:788–795. © 2010 Wiley‐Liss, Inc.
Comparison of segmentation methods for MRI measurement of cardiac function in rats
Authors: Riegler Johannes , Cheung King K. , Man Yiu Fung , Cleary Jon O. , Price Anthony N. , Lythgoe Mark F. 
Published: September 2010

AbstractPurposeTo establish the accuracy, intra‐ and inter‐observer variabilities of four different segmentation methods for measuring cardiac functional parameters in healthy and infarcted rat hearts.Materials and MethodsSix Wistar rats were imaged before and after myocardial infarction using an electrocardiogram and respiratory‐gated spoiled gradient echo sequence. Blinded and randomized datasets were analyzed by various semi‐automatic and manual segmentation methods to compare their measurement bias and variability. In addition, the accuracy of these methods was assessed by comparison with reference measurements acquired from high‐resolution three‐dimensional (3D) datasets of a heart phantom.ResultsRelative inter‐ and intra‐observer variability were found to be similar for all four methods. Semi‐automatic segmentation methods reduced analysis time by up to 70%, while yielding similar measurement bias and variability compared with manual segmentation. Semi‐automatic methods were found to underestimate the ejection fraction for healthy hearts compared with manual segmentation while overestimating them in infarcted hearts. However, semi‐automatic segmentation of short axis slices agreed better with 3D reference scans of a heart phantom compared with manual segmentation.ConclusionSemi‐automatic segmentation methods are faster than manual segmentation, while offering a similar intra‐ and inter‐observer variability. However, a potential bias has been observed between healthy and infarcted hearts for different methods, which should also be considered when selecting the most appropriate analysis technique. J. Magn. Reson. Imaging 2010;32:869–877. © 2010 Wiley‐Liss, Inc.
Longitudinal and multi‐echo transverse relaxation times of normal breast tissue at 3 Tesla
Authors: Edden Richard A.E. , Smith Seth A. , Barker Peter B. 
Published: September 2010

AbstractPurposeTo measure longitudinal (T1) and multi‐echo transverse (T2) relaxation times of healthy breast tissue at 3 Tesla (T).Materials and MethodsHigh‐resolution relaxation time measurements were made in six healthy female subjects. Inversion recovery images were acquired at 10 inversion times between 100 ms and 4000 ms, and multiple spin echo images were acquired at 16 echo times between 10 ms and 160 ms.ResultsLongitudinal relaxation times T1 were measured as 423 ± 12 ms for adipose tissue and 1680 ± 180 ms for fibroglandular tissue. Multi‐echo transverse relaxation times T2 were measured as 154 ± 9 ms for adipose tissue and 71 ± 6 ms for fibroglandular tissue. Histograms of the voxel‐wise relaxation times and quantitative relaxation time maps are also presented.ConclusionT1 and multi‐echo T2 relaxation times in normal human breast tissue are reported. These values are useful for pulse sequence design and optimization for 3T breast MRI. Compared with the literature, T1 values are significantly longer at 3T, suggesting that longer repetition time and inversion time values should be used for similar image contrast. J. Magn. Reson. Imaging 2010;32:982–987. © 2010 Wiley‐Liss, Inc.