bluuebunny/crossref_metadata_2025_split huggingface dataset:
Integration of synchronous synaptic input in CA1 pyramidal neuron depends on spatial and temporal distributions of the input
Authors: Tigerholm Jenny , Migliore Michele , Fransén Erik 
Published: September 2012

AbstractHighly synchronized neural firing has been discussed in relation to learning and memory, for instance sharp‐wave activity in hippocampus. We were interested to study how a postsynaptic CA1 pyramidal neuron would integrate input of different levels of synchronicity. In previous work using computational modeling we studied how the integration depends on dendritic conductances. We found that the transient A‐type potassium channel KA was able to selectively suppress input of high synchronicity. In recent years, compartmentalization of dendritic integration has been shown. We were therefore interested to study the influence of localization and pattern of synaptic input over the dendritic tree of the CA1 pyramidal neuron. We find that the selective suppression increases when synaptic inputs are placed on oblique dendrites further out from the soma. The suppression also increases along the radial axis from the apical trunk out to the end of oblique dendrites. We also find that the KA channel suppresses the occurrence of dendritic spikes. Moreover, recent studies have shown interaction between synaptic inputs. We therefore studied the influence of apical tuft input on the integration studied above. We find that excitatory input provides a modulatory influence reducing the capacity of KA to suppress synchronized activity, thus facilitating the excitatory drive of oblique dendritic input. Conversely, inhibitory tuft input increases the suppression by KA providing a larger control of oblique depolarizing factors on the CA1 pyramidal neuron in terms of what constitutes the most effective level of synchronicity. Furthermore, we show that the selective suppression studied above depends on the conductance of the KA channel. KA, as several other potassium channels, is modulated by several neuromodulators, for instance acetylcholine and dopamine, both of which have been discussed in relation to learning and memory. We suggest that dendritic conductances and their modulatory systems may be part of the regulation of processing of information, in particular for how network synchronicity affects learning and memory. © 2012 Wiley Periodicals, Inc.
Endogenous hippocampal LTD that is enabled by spatial object recognition requires activation of NMDA receptors and the metabotropic glutamate receptor, mGlu5
Authors: Goh Jinzhong Jeremy , Manahan‐Vaughan Denise 
Published: September 2012

AbstractLearning‐facilitated synaptic plasticity describes the ability of hippocampal synapses to respond with persistent plasticity to afferent stimulation when coupled with a spatial learning event, whereby the afferent stimulation normally produces short‐term plasticity or no change in synaptic strength if given in the absence of novel learning. Recently, it was reported that in the mouse hippocampus intrinsic long‐term depression (LTD > 24 h) occurs when test‐pulse afferent stimulation is coupled with a novel spatial learning. It is not known to what extent this phenomenon shares molecular properties with synaptic plasticity that is typically induced by means of patterned electrical afferent stimulation. In previous work, we showed that a novel spatial object recognition task facilitates LTD at the Schaffer collateral—CA1 synapse of freely behaving adult mice, whereas reexposure to the familiar spatial configuration ∼24 h later elicited no such facilitation. Here we report that treatment with the NMDA receptor antagonist, (±)‐3‐(2‐Carboxypiperazin‐4‐yl)‐propanephosphonic acid (CPP), or antagonism of metabotropic glutamate (mGlu) receptor, mGlu5, using 2‐methyl‐6‐(phenylethynyl) pyridine (MPEP), completely prevented LTD under the novel learning conditions. Behavioral assessment during re‐exposure after application of the antagonists revealed that the animals did not remember the object during novel exposure and treated them as if they were novel. Under these circumstances, where the acquisition of novel spatial information was involved, LTD was facilitated. Our data support that the endogenous LTD that is enabled through novel spatial learning in adult mice is critically dependent on the activation of both the NMDA receptors and mGlu5. © 2012 Wiley Periodicals, Inc.
ZnO, SiO2, and SrO doping in resorbable tricalcium phosphates: Influence on strength degradation, mechanical properties, and in vitro bone–cell material interactions
Authors: Bandyopadhyay Amit , Petersen Johanna , Fielding Gary , Banerjee Shashwat , Bose Susmita 
Published: September 2012

AbstractTo understand the combined effects of ZnO, SiO2, and SrO doping on mechanical and biological properties of tricalcium phosphate (TCP) ceramics, dense β‐TCP compacts of different compositions (pure β‐TCP; 1.0 wt % SrO; 0.25 wt % ZnO; 1.0 wt % SrO + 0.5 wt % SiO2; and 1.0 wt % SrO + 0.25 wt % ZnO) were prepared via dry pressing followed by sintering at 1250°C. X‐ray diffraction of sintered compacts revealed that dopants retarded β‐ to α‐TCP phase transformation during sintering. Doping with SrO, SrO/SiO2, and SrO/ZnO reduced compressive strength of the samples to 56% (173 ± 25 MPa), 57% (170 ± 15 MPa), and 47% (208 ± 72 MPa) of pure β‐TCP (396 ± 58 MPa), respectively. However, addition of ZnO resulted in only 7% (365 ± 69 MPa) strength degradation. The impact of dopants on long‐term in vitro strength degradation was evaluated by soaking in simulated body fluid (SBF) for a period of 8 weeks. In all cases, excellent apatite growth was observed on doped β‐TCP samples. However, strength degradation rates were different depending on dopant chemistry and composition. Maximum degradation was observed in undoped and ZnO‐doped β‐TCP samples, which degraded to 41% and 68% of the original strength before soaking in SBF. Finally, in vitro cell–materials interaction study using human fetal osteoblast cells demonstrated that addition of dopants improved cell attachment and proliferation. These results indicate that tailorable strength and strength degradation behavior can be achieved in β‐TCP via compositional modifications using small amount of dopants. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.
Wear of a dental composite in an artificial oral environment: A clinical correlation
Authors: DeLong Ralph , Pintado Maria R. , Douglas William H. , Fok Alex S. , Wilder Aldridge D. , Swift Edward J. , Bayne Stephen C. 
Published: September 2012

AbstractThe study objective was to correlate wear between an in vitro method for simulating wear and in vivo wear of a posterior dental composite. Ten subjects (12 restorations) were selected from a five‐year clinical study (University of North Carolina, School of Dentistry) that assessed wear of SureFil composite (Caulk, Dentsply). Subject casts were digitized and changes in volume and mean depth with time were calculated from the 3D digital models for contact and contact‐free wear. SureFil composite disks were mounted in the University of Minnesota's Artificial Oral Environment, opposed by natural enamel, subjected to mandibular‐like movements for 150 K, 300 K, 600 K, 1.2 M, and 1.5 M cycles, and loaded with peak forces of 13 N (n = 7) or 30 N (n = 3). Wear rates were calculated as the slope of the linear regressions fitting the wear data. Data were analyzed using one‐way ANOVAs and post hoc t‐tests where appropriate (p = 0.05). Clinical restorations included contact wear on seven restorations and contact‐free wear on all restorations. Contact‐free wear was less than contact wear (p < 0.01). SureFil clinical wear rates were 0.012 mm/year (mean depth) and 0.023 mm3/year (volume). Clinical restorations expanded slightly during the first year. Using a conversion rate of one year equals 3 × 105 cycles, there were no significant differences between the clinical and simulated data except depths at Year 5 and 13 N volume at Year 4. The 30 N simulation reproduced the clinical data if contact‐free wear was taken into account. Good agreement between simulated and clinical wear implies that in vitro simulation can screen new composite formulations. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.
In vivo oxidation in retrieved highly crosslinked tibial inserts
Authors: Currier B. H. , Van Citters D. W. , Currier J. H. , Carlson E. M. , Tibbo M. E. , Collier J. P. 
Published: September 2012

AbstractThe current study determined (I) the environment where oxidation in a series of retrieved, HXL UHMWPE tibial inserts occurred (in vivo or postexplant); and (II) the effect of fabrication variables (irradiation source, irradiation dose) and thermal processing after irradiation (annealing or remelting) on oxidation resistance. Hypotheses examined are (1) HXL UHMWPE tibial inserts have potential to oxidize in vivo, and (2) annealed HXL UHMWPE oxidizes at a higher rate in vivo than remelted HXL UHMWPE. Highly crosslinked UHMWPE tibial inserts (87), received by an IRB‐approved retrieval laboratory from 20 surgeons at 10 institutions across the U.S., were analyzed from 2005 to 2011. Fourier transform infrared spectroscopy was used to determine oxidation and trans‐vinylene index for each retrieved insert. Measured oxidation that was maximum subsurface was found in 56% of all HXL tibial inserts. This maximum oxidation correlated significantly with in vivo time, trans‐vinylene index, and thermal processing after irradiation. Articular oxidation rate correlated with crosslinking irradiation dose and thermal processing after irradiation. Retrieved below‐melt annealed tibial inserts had significantly higher articular oxidation rates than remelted tibial inserts (p < 0.001). Articular oxidation rates correlated positively with cross‐linking irradiation dose and postirradiation thermal processing. Edge oxidation correlated with postirradiation thermal processing. Oxidation of HXL UHMWPE may have clinical implications for tibial inserts, since loss of UHMWPE toughness resulting from oxidation has led to fatigue damage in gamma‐sterilized tibial inserts. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 101B: 441–448, 2013.
Quantitative in vitro assessment of Mg65Zn30Ca5 degradation and its effect on cell viability
Authors: Cao Jake D. , Martens Penny , Laws Kevin J. , Boughton Philip , Ferry Michael 
Published: September 2012

AbstractA bulk metallic glass (BMG) of composition Mg65Zn30Ca5 was cast directly from the melt and explored as a potential bioresorbable metallic material. The in vitro degradation behavior of the amorphous alloy and its associated effects on cellular activities were assessed against pure crystalline magnesium. Biocorrosion tests using potentiodynamic polarization showed that the amorphous alloy corroded at a much slower rate than the crystalline Mg. Analysis of the exchanged media using inductively coupled plasma optical emission spectrometry revealed that the dissolution rate of Mg ions in the BMG was 446 μg/cm2/day, approximately half the rate of crystalline Mg (859 μg/cm2/day). A cytotoxicity study, using L929 murine fibroblasts, revealed that both the BMG and pure Mg are capable of supporting cellular activities. However, direct contact with the samples created regions of minimal cell growth around both amorphous and crystalline samples, and no cell attachment was observed. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 101B: 43–49, 2013.
Potentiodynamic polarization study on electropolished nitinol vascular implants
Authors: Wohlschlögel Markus , Steegmüller Rainer , Schüβler Andreas 
Published: September 2012

AbstractThe electrochemical properties of electropolished Nitinol vascular implants manufactured in a serial‐production manner starting with laser cutting of tubing and ending with electropolishing and final inspection were analyzed and evaluated over a time period of 1 year. Potentiodynamic polarization tests in phosphate‐buffered saline were conducted on over 1250 Nitinol implants covering the entire serial production range at ADMEDES Schuessler GmbH – from tiny stents for neurovascular applications up to large heart valve frames. Breakdown potentials were evaluated and correlated to product group, properties of the semifinished material and raw material supplier. Results of this study give clear indications for the interrelation between material quality and the event of electrochemical breakdown in a potentiodynamic polarization test. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.
Plasma and red cell exchange transfusions for erythropoietic protoporphyria: A case report and review of the literature
Authors: Pagano Monica B. , Hobbs William , Linenberger Michael , Delaney Meghan 
Published: September 2012

AbstractErythropoietic protoporphyria (EPP) is a rare and usually autosomal dominant disorder characterized by ferrochelatase deficiency and accumulation of protoporphyrin in red blood cells (RBCs), skin, and liver. A small minority of patients develop severe liver dysfunction for which optimum treatment is lacking. Therapeutic plasma exchange (TPE) and RBC exchange (RCE) have been anecdotally reported to benefit patients with EPP and liver failure. A 50‐year‐old female with EPP developed severe liver dysfunction after knee replacement surgery and high‐dose acetaminophen use. Liver biopsy showed cholestatic liver injury without fibrosis. A total of 20 TPE procedures, six RCE procedures, and then 14 more TPE procedures were performed as adjunctive therapy with the purpose of preventing progression to end‐stage liver failure. After initial TPE, the plasma and RBC protoporphyrin levels decreased from 834.9 to 180.4 μg/dL (normal, ≤1 μg/dL), and from 3,905 to 2,879 μg/dL (normal, ≤80 μg/dL), respectively, without liver function improvement. RCE decreased RBC protoporphyrin levels from 2,879 to 1,225 μg/dL but plasma protoporphyrin increased from 180.4 to 1,044.1 μg/dL, and liver function failed to improve. Additional TPE again stabilized plasma protoporphyrin and improved RBC protoporphyrin levels but the patient ultimately died owing to end‐stage liver disease complications. This case illustrates that TPE and RCE may improve the plasma and RBC biochemical markers of EPP activity but liver function abnormalities may persist and patients may still progress to liver failure either because of irreversible liver injury or independent pathobiological factors unrelated to EPP‐induced hepatotoxicity. J. Clin. Apheresis, 2012. © 2012 Wiley Periodicals, Inc.
Association of Genetic Variations in X‐Ray Repair Cross‐Complementing Group 1 and Tourette Syndrome
Authors: Lin Wei‐Yong , Lee Cheng‐Chun , Liu Hsin‐Ping , Chou I‐Ching , Sheu Jim Jinn‐Chyuan , Wan Lei , Lin Ying‐Ju , Tsai Yuhsin , Tsai Fuu‐Jen 
Published: September 2012

BackgroundX‐ray repair cross‐complementing group 1 (XRCC1) plays a central role in mammalian DNA repair process. The polymorphism rs25487 (Arg>Gln at codon 399) of this gene is common in Han Chinese population.ObjectivesThe objective of this study was to analyze the association between this functional SNP of XRCC1 and Tourette syndrome (TS) in Han Taiwan Chinese population.MethodsGenotyping was performed by using PCR–RFLP method on 73 TS patients and 158 normal controls.ResultsOur data indicated that genotype frequency of A/G polymorphism at codon 399 of the patients differed from the controls (P = 0.026, OR: 2.22, 95% CI: 1.22–4.03). The allele frequency analysis also showed significant differences with higher A allele frequency in patients (P = 0.015, OR: 1.70, 95% CI: 1.11–2.62).ConclusionOur study indicates that the functional SNP at codon 399 of XRCC1 is associated with TS development. J. Clin. Lab. Anal. 26:321‐324, 2012. © 2012 Wiley Periodicals, Inc.
Relationship of Fat Distribution With Adipokines in Patients With Acquired Immunodeficiency Virus Infection
Authors: de Luis Daniel A. , Bachiller Pablo , Palacios Teresa , Conde Rosa , Izaola Olatz , de la Fuente Beatriz , Eiros Bouza Jose M. 
Published: September 2012

BackgroundThe aim was to examine the relationship of fat distributions with adipokines concentrations in HIV‐infected patients.MethodsThis was a cross‐sectional analysis of 36 HIV (free of lipodystrophy) infected patients. Dual‐energy X‐ray absorptiometry was used.ResultsIn the multivariate analysis, basal adiponectin concentration was a dependent variable, whereas waist to hip ratio and abdominal fat mass were independent predictors in the model (F = 5.1; P < 0.05). Adiponectin concentration decreases by 5.541.2 μg/ml (CI 95%: 8,071.9–3,029.1) for each unit of waist to hip ratio and 561.9 ng/ml (CI 95%: 918.2–213.4) for each kilogram of fat mass of abdominal area. In the multivariate analysis, basal leptin concentration was a dependent variable, whereas waist circumference remained an independent predictor in the model (F = 6.3; P < 0.05), with a direct correlation. Leptin concentration increases by 0.067 ng/ml (CI 95%: 0.001–0.12) for each centimeter of waist circumference.ConclusionsLeptin and adiponectin are related with adiposity in HIV‐infected patients. J. Clin. Lab. Anal. 26:336‐341, 2012. © 2012 Wiley Periodicals, Inc.
Measurement of Urinary Cystatin C with a Particle‐Enhanced Turbidimetric Immunoassay on Architect Ci8200
Authors: Noraddin Feria Hikmet , Flodin Mats , Fredricsson Annika , Sohrabian Azita , Larsson Anders 
Published: September 2012

BackgroundCystatin C is a low‐molecular‐weight protein that is freely filtered by the glomerulus and catabolized after reabsorption by the proximal tubular cells in healthy subjects. Urinary cystatin C is a potential biomarker for tubular damage including acute kidney injury (AKI) in the acute phase when patients are submitted to the intensive care unit.MethodsThe aim of this study was to perform a method validation of urinary analysis of cystatin C by particle‐enhanced turbidimetric immunoassay (PETIA) on a high‐throughput chemical analyzer. Total assay time was 10 min. The antigen excess, linearity, lower limit of quantification (LoQ), recovery, assay precision, stability, and interference caused by hemoglobin were evaluated.ResultsThe LoQ was calculated to 0.020 mg/l with a coefficient of variation (CV) ≤ 10%. No hook effect was observed and the assay was linear over the studied interval less than 0.020–0.950 mg/l with a regression of R2 = 0.9994. The assay had a recovery between 93–100% and the assay precision had a total CV of less than 3.5%. Cystatin C was stable for 3 days in room temperature and 14 days in +4C. The assay did not show any major interference with hemoglobin at a hemoglobin concentration of 10 g/L. The reference interval for urine cystatin C was less than 0.166 mg/l.ConclusionThe urinary cystatin C PETIA showed good precision and performance characteristics including short test turnaround times that are necessary qualifications for a biomarker at a routine laboratory. J. Clin. Lab. Anal. 26:358‐364, 2012. © 2012 Wiley Periodicals, Inc.
Stability of Electrolyte Determinations on the Siemens Advia 1800 Analyzer
Authors: Garcia Rafael , Li Geling , Wang Zhenglong , Cabanero Michael , Pincus Matthew R. 
Published: September 2012

BackgroundIt is sometimes necessary for the laboratory to re‐test samples for critical serum electrolyte levels. It is important to assure reproducibility of results when testing is performed on stored, refrigerated samples. We have tested the reproducibility of results for the critical electrolytes, Na, K, Cl and Ca, from ten randomly selected patients'sera over our maximum storage period of nine (9) days on the Siemens Advia 1800 analyzer. The ranges for each electrolyte were 131–150 meq/L (Na), 3.4–5.2 meq/L (K), 101–123 meq/L (Cl) and 7.3–9.9 mg/dL (Ca).MethodsWe used ion‐selective electrodes for Na, K and Cl and the ortho‐cresolphthalein dye method for Ca.ResultsWe find that the reproducibility of determinations for all of these electrolytes was excellent, i.e. the coefficients of variation for each electrolyte determination for each patient were low.ConclusionThe methods of measurement for these electrolytes on the Advia 1800 are reliable and reproducible. J. Clin. Lab. Anal. 26:372‐375, 2012. Published 2012. This article is a U.S. Government work and is in the public domain the USA.
Increased MPV Is Not a Significant Predictor for Preeclampsia During Pregnancy
Authors: Altınbas Sibel , Toğrul Cihan , Orhan Anıl , Yücel Munihe , Danısman Nuri 
Published: September 2012

BackgroundPreeclampsia, defined as the presence of hypertension and proteinuria, is usually related with maternal and neonatal adverse effects. However, the exact predictor of preeclampsia is still lacking. Even though there are some conflicting data, mean platelet value or MPV, that is, platelet ratio with or without Doppler velocimetry was determined as highly sensitive markers for preeclampsia. We aimed to investigate the utility of MPV in prediction of preeclampsia.MethodsSeventy‐four preeclamptic pregnant women (21 in mild, 53 in severe preeclampsia groups) were included in the study. To assess the difference of MPV between preeclamptic, normal pregnant, and healthy control rather than mild and severe preeclamptic pregnant women, we included in the analysis 31 healthy pregnant women and 35 healthy nonpregnant women.ResultsMean age of the preeclamptic patients was 25.3 (17–38) years. Platelet levels were higher in mild preeclampsia (group 1) than severe preeclampsia (group 2), whereas alanine aminotransferase (AST), hemoglobin, and hematocrit level was higher in group 2. MPV levels were found to be similar in groups 1 and 2, MPV level increased from healthy control to preeclamptic women (P = 0.003). MPV:platelet ratio was similar according to the severity of preeclampsia (P = 0.123). Doppler velocimetry did not add an additional benefit to predict preeclampsia or its severity.ConclusionOur results showed that MPV level was higher in the pregnant than the control group. However, MPV did not differ both between mild and severe preeclampsia, and preeclampsia and non‐preeclamptic pregnant women. J. Clin. Lab. Anal. 26:403‐406, 2012. © 2012 Wiley Periodicals, Inc.
Differential mechanisms of tumor progression in clones from a single heterogeneous human melanoma
Authors: Croteau Walburga , Jenkins Molly H. , Ye Siying , Mullins David W. , Brinckerhoff Constance E. 
Published: September 2012

AbstractWe used vertical growth phase (VGP) human VMM5 melanoma cells to ask whether the tumor microenvironment could induce matrix metalloproteinase‐1 (MMP‐1) in vivo, and whether this induction correlated with metastasis. We isolated two clones from parental VMM5 cells: a low MMP‐1 producing clone (C4) and high producing clone (C9). When these clones were injected orthotopically (intradermally) into nude mice, both were equally tumorigenic and produced equivalent and abundant amounts of MMP‐1. However, the tumors from the C4 clones displayed different growth kinetics and distinct profiles of gene expression from the C9 population. The C4 tumors, which had low MMP‐1 levels in vitro, appeared to rely on growth factors and cytokines in the microenvironment to increase MMP‐1 expression in vivo, while MMP‐1 levels remained constant in the C9 tumors. C9 cells, but not C4 cells, grew as spheres in culture and expressed higher levels of JARID 1B, a marker associated with melanoma initiating cells. We conclude that VMM5 melanoma cells exhibit striking intra‐tumor heterogeneity, and that the tumorigenicity of these clones is driven by different molecular pathways. Our data suggest that there are multiple mechanisms for melanoma progression within a tumor, which may require different therapeutic strategies. J. Cell. Physiol. 228: 773–780, 2013. © 2012 Wiley Periodicals, Inc.