bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrophysiological evidence of GABAA and GABAC receptors on zebrafish retinal bipolar cells
Authors: CONNAUGHTON VICTORIA P. , NELSON RALPH , BENDER ANNA M. 
Published: April 2008

AbstractTo refine inhibitory circuitry models for ON and OFF pathways in zebrafish retina, GABAergic properties of zebrafish bipolar cells were studied with two techniques: whole cell patch responses to GABA puffs in retinal slice, and voltage probe responses in isolated cells. Retinal slices documented predominantly axon terminal responses; isolated cells revealed mainly soma-dendritic responses. In the slice, GABA elicited a conductance increase, GABA responses were more robust at axon terminals than dendrites, and Erev varied with [Cl−]in. Axon terminals of ON- and OFF-type cells were similarly sensitive to GABA (30–40 pA peak current); axotomized cells were unresponsive. Bicuculline-sensitive, picrotoxin-sensitive, and picrotoxin-insensitive components were identified. Muscimol was as effective as GABA; baclofen was ineffective. Isolated bipolar cells were either intact or axotomized. Even in cells without an axon, GABA or muscimol (but not baclofen) hyperpolarized dendritic and somatic regions, suggesting significant distal expression. Median fluorescence change for GABA was −0.22 log units (∼ −16 mV); median half-amplitude dose was 0.4 μM. Reduced [Cl−]out blocked GABA responses. GABA hyperpolarized isolated ON-bipolar cells; OFF-cells were either unresponsive or depolarized. Hyperpolarizing GABA responses in isolated cells were bicuculline and TPMPA insensitive, but blocked or partially blocked by picrotoxin or zinc. In summary, axon terminals contain bicuculline-sensitive GABAA receptors and both picrotoxin-sensitive and insensitive GABAC receptors. Dendritic processes express zinc- and picrotoxin-sensitive GABAC receptors.
Reply to Philipona and O'Regan
Authors: JOHNSON KENT , WRIGHT WAYNE 
Published: April 2008

AbstractThis paper responds to Philipona and O'Regan (2006), which attempts to account for certain color phenomena by appeal to singularities in the space of “accessible information” in the light striking the retina. Three points are discussed. First, it is unclear what the empirical significance/import is of the mathematical analysis of the data regarding the accessible information in the light. Second, the singularity index employed in the study is both mathematically and empirically faulty. Third, the connection drawn between their findings and some data from the World Color Survey is lacking in quantitative analysis in places where it is needed. The difficulties raised prevent Philipona & O'Regan's conclusions from being accepted.
Long-term cellular and regional specificity of the photoreceptor toxin, iodoacetic acid (IAA), in the rabbit retina
Authors: LIANG LI , KATAGIRI YOSHIAKI , FRANCO LUISA M. , YAMAUCHI YASUYUKI , ENZMANN VOLKER , KAPLAN HENRY J. , SANDELL JULIE H. 
Published: April 2008

AbstractThis study investigated the anatomical consequences of a photoreceptor toxin, iodoacetic acid (IAA), in the rabbit retina. Retinae were examined 2 weeks, 1, 3, and 6 months after systemic IAA injection. The retinae were processed using standard histological methods to assess the gross morphology and topographical distribution of damage, and by immunohistochemistry to examine specific cell populations in the retina. Degeneration was restricted to the photoreceptors and was most common in the ventral retina and visual streak. In damaged regions, the outer nuclear layer was reduced in thickness or eliminated entirely, with a concomitant loss of immunoreactivity for rhodopsin. However, the magnitude of the effect varied between animals with the same IAA dose and survival time, suggesting individual differences in the bioavailability of the toxin. In all eyes, the inner retina remained intact, as judged by the thickness of the inner nuclear layer, and by the pattern of immunoreactivity for protein kinase C-α (rod bipolar cells) and calbindin D-28 (horizontal cells). Müller cell stalks became immunoreactive for glial fibrillary acidic protein (GFAP) even in IAA-treated retinae that had no signs of cell loss, indicating a response of the retina to the toxin. However, no marked hypertrophy or proliferation of Müller cells was observed with either GFAP or vimentin immunohistochemistry. Thus the selective, long lasting damage to the photoreceptors produced by this toxin did not lead to a reorganization of the surviving cells, at least with survival as long as 6 months, in contrast to the remodeling of the inner retina that is observed in inherited retinal degenerations such as retinitis pigmentosa and retinal injuries such as retinal detachment.
Retinal ganglion cell density of the black rhinoceros (Diceros bicornis): Calculating visual resolution
Authors: PETTIGREW JOHN D. , MANGER PAUL R. 
Published: April 2008

AbstractA single right retina from a black rhinoceros was whole mounted, stained and analyzed to determine the visual resolution of the rhinoceros, an animal with reputedly poor eyesight. A range of small (15-μm diameter) to large (100-μm diameter) ganglion cell types was seen across the retina. We observed two regions of high density of retinal ganglion cells at either end of a long, but thin, horizontal streak. The temporal specialization, which receives light from the anterior visual field, exhibited a ganglion cell density of approximately 2000/mm2, while the nasal specialization exhibited a density of approximately 1500/mm2. The retina exhibited a ganglion cell density bias toward the upper half, especially so, the upper temporal quadrant, indicating that the rhinoceros would be processing visual information from the visual field below the anterior horizon for the most part. Our calculations indicate that the rhinoceros has a visual resolution of 6 cycles/degree. While this resolution is one-tenth that of humans (60 cycles/deg) and less than that of the domestic cat (9 cycles/deg), it is comparable to that of the rabbit (6 cycles/deg), and exceeds that seen in a variety of other mammals including seals, dolphins, microbats, and rats. Thus, the reputation of the rhinoceros as a myopic, weakly visual animal is not supported by our observations of the retina. We calculate that the black rhinoceros could readily distinguish a 30 cm wide human at a distance of around 200 m given the appropriate visual background.
Responses to direction and transparent motion stimuli in area FST of the macaque
Authors: ROSENBERG ARI , WALLISCH PASCAL , BRADLEY DAVID C. 
Published: April 2008

AbstractMotion transparency occurs when multiple object velocities are present within a local region of retinotopic space. Transparent signals can carry information useful in the segmentation of moving objects and in the extraction of three-dimensional structure from relative motion cues. However, the physiological substrate underlying the detection of motion transparency is poorly understood. Direction tuned neurons in area MT are suppressed by transparent stimuli, suggesting that other motion sensitive areas may be needed to represent this signal robustly. Recent neuroimaging evidence implicated two such areas in the macaque superior temporal sulcus. We studied one of these, FST, with electrophysiological methods and found that a large fraction of the neurons responded well to two opposite directions of motion and to transparent stimuli containing those same directions. A linear combination of MT-like responses qualitatively reproduces this behavior and predicts that FST neurons can be tuned for transparent motion containing specific direction and depth components. We suggest that FST plays a role in motion segmentation based on transparent signals.
Introduction to the Special Issue: A Perspective on Magsat Results
Authors: Langel Robert A. 
Published: April 2008

It is now over 4 years since the Magsat spacecraft reentered the earth's atmosphere. By almost any measure the project has been a success: launch was within budget and on time; the data acquired exceeded prelaunch quality requirements even though the instrumentation encountered some problems; with the publication of this issue, the number of related scientific papers is near 100.Magsat project objectives were (1) to obtain accurate vector measurements of the near‐earth geomagnetic field and (2) to use those measurements to identify and model the main (core) and crustal fields. The main field measurements were to be used for the 1980 world charts and for studies of earth's core. The crustal field estimates were to be utilized to aid in modeling large‐scale variations in the geologic and geophysical characteristics of the crust. Although not a primary Magsat objective, studies of fields from external sources were also carried out.
Findings From an Accelerated in vivo Corrosion Model of Magnesium
Authors: Yuen Chi Keung , Ip Wing Yuk 
Published: April 2008

AbstractIn this article, we are presenting some findings of magnesium corrosion in an in vivo model. While there is consensus that subcutaneous bubbles will occur, it was found in our corrosion-accelerated model that magnesium corrosion is more severe in areas under the gas bubbles. This finding may bring insights to novel methods in reducing the uneven corrosion.
Resource Allocation and Managerial Oversight of Local Morning Newscasts
Authors: Wenger Debora Halpern , Owens Lynn C. 
Published: April 2008

In this mixed-methods study of local morning newscasts, the researchers examine current approaches to managerial oversight and resource allocation for morning newscasts and explore the content focus and expansion plans for the time period. A Web survey of 117 news directors found no significant differences between number-one rated stations and non-number-one rated stations in terms of the number of hours of news produced, the number of times per week managers watch the morning shows or discuss shows with their staffs, or the staff sizes on morning shows. However, the vast majority of respondents believe that a combination of adding staff and providing greater managerial oversight to the morning news block would be the most effective way to boost a station's morning news ratings. In-depth interviews with news directors for some of the highest-rated morning newscasts in the country describe how they update content and set the agenda for the day to create their successful morning news programs.
The effect of sunlight on leaf litter quality reduces growth of the shredderKlapopteryx kuscheli
Authors: ALBARIÑO RICARDO , VILLANUEVA VERÓNICA DÍAZ , CANHOTO CRISTINA 
Published: April 2008

SummaryThe direct effect of sunlight on the conditioning, breakdown and incorporation of leaf litter in stream food webs has not yet been considered. The aim here was to evaluate the effects of light intensity on the colonization of leaf litter by microorganisms and its resulting quality as food for the stonefly shredderKlapopteryx kuscheli.Leaf litter was conditioned for 2 months in an open reach of a second‐order stream in litter bags either exposed to or shaded from direct sunlight. Subsequently, we performed laboratory experiments to test larval consumption, growth, growth efficiency and feeding preference fed on both leaf litter treatments.Leaf litter in the unshaded treatment had three times more chlorophyll‐a(Chl‐a) than that in the shaded treatment, 50% lower fungal biomass and similar bacterial abundance. Although larvae did not prefer either food and fed at the same rate on both leaf litter treatments, they grew twice as fast on the shade‐conditioned leaves and attained a two‐fold higher growth efficiency.Sunlight can have significant effects on detritus‐based food webs. Riparian modification induced by human activities in forested catchments increases the potential for sunlight to influence detritus dynamics.
Serum lipids regulate dendritic cell CD1 expression and function
Authors: Leslie David S. , Dascher Christopher C. , Cembrola Katherine , Townes Maria A. , Hava David L. , Hugendubler Lynne C. , Mueller Elisabetta , Fox Lisa , Roura‐Mir Carme , Moody D. Branch , Vincent Michael S. , Gumperz Jenny E. , Illarionov Petr A. , Besra Gurdyal S. , Reynolds Carol G. , Brenner Michael B. 
Published: April 2008

SummaryDendritic cells (DCs) are highly potent antigen‐presenting cells (APCs) and play a vital role in stimulating naïve T cells. Treatment of human blood monocytes with the cytokines granulocyte–macrophage colony‐stimulating factor (GM‐CSF) and interleukin (IL)‐4 stimulates them to develop into immature dendritic cells (iDCs) in vitro. DCs generated by this pathway have a high capacity to prime and activate resting T cells and prominently express CD1 antigen‐presenting molecules on the cell surface. The presence of human serum during the differentiation of iDCs from monocytes inhibits the expression of CD1a, CD1b and CD1c, but not CD1d. Correspondingly, T cells that are restricted by CD1c showed poor responses to DCs that were generated in the presence of human serum, while the responses of CD1d‐restricted T cells were enhanced. We chemically fractionated human serum to isolate the bioactive factors that modulate surface expression of CD1 proteins during monocyte to DC differentiation. The human serum components that affected CD1 expression partitioned with polar organic soluble fractions. Lysophosphatidic acid and cardiolipin were identified as lipids present in normal human serum that potently modulate CD1 expression. Control of CD1 expression was mediated at the level of gene transcription and correlated with activation of the peroxisome proliferator‐activated receptor (PPAR) nuclear hormone receptors. These findings indicate that the ability of human DCs to present lipid antigens to T cells through expression of CD1 molecules is sensitively regulated by lysophosphatidic acid and cardiolipin in serum, which are ligands that can activate PPAR transcription factors.
Widespread natural variation in murine natural killer T‐cell number and function
Authors: Rymarchyk Stacia L. , Lowenstein Hayden , Mayette Jana , Foster Samantha R. , Damby David E. , Howe Isaac W. , Aktan Idil , Meyer Russell E. , Poynter Matthew E. , Boyson Jonathan E. 
Published: April 2008

SummaryNatural killer T (NKT) cells comprise a novel T‐lymphocyte subset that can influence a wide variety of immune responses through their ability to secrete large amounts of a variety of cytokines. Although variation in NKT‐cell number and function has been extensively studied in autoimmune disease‐prone mice, in which it has been linked to disease susceptibility, relatively little is known of the natural variation of NKT‐cell number and function among normal inbred mouse strains. Here, we demonstrate strain‐dependent variation in the susceptibility of C57BL/6J and BALB/cJ mice to NKT‐mediated airway hyperreactivity, which correlated with significant increases in serum interleukin‐4 (IL‐4) and IL‐13 elicited by the synthetic glycosphingolipid α‐galactosylceramide. Examination of NKT‐cell function revealed a significantly greater frequency of cytokine‐producing NKT cells in C57BL/6J versus BALB/cJ mice as well as significant differences in the kinetics of NKT‐cell cytokine production. Extension of this analysis to a panel of inbred mouse strains indicated that variability in NKT‐cell cytokine production was widespread. Similarly, an examination of NKT‐cell frequency revealed a significantly greater number of liver NKT cells in the C57BL/6J mice versus BALB/cJ mouse livers. Again, examination of a panel of inbred mouse strains revealed that liver NKT‐cell numbers were quite variable, spanning over a 100‐fold range. Taken together, these results demonstrate the presence of widespread natural variation in NKT‐cell number and function among common inbred mouse strains, which may have implications for the examination of the influence of NKT cells in immune responses and disease pathogenesis among different genetic backgrounds.
A modified version of the Bayley Scales of Infant Development‐II for cognitive matching of infants with and without Down syndrome
Authors: Moore D. G. , Goodwin J. E. , Oates J. M. 
Published: April 2008

AbstractBackground  Many measures of infants' early cognitive development, including the BSID‐II (The Bayley Scales of Infant Development), mix together test items that assess a number of different developmental domains including language, attention, motor functioning and social abilities, and some items contribute to the assessment of more than one domain. Consequently, the scales may lead to under‐ or over‐estimates of cognitive abilities in some clinical samples and may not be the best measure to use for matching purposes.Method  To address this issue we created a modified form of the BSID‐II (the BSID‐M) to provide a ‘purer’ assessment of the general cognitive capacities in infants with Down syndrome (DS) from 6 to 18 months of age. We excluded a number of items that implicated language, motor, attentional and social functioning from the original measure. This modified form was administered to 17 infants with Down syndrome when 6, 12 and 18 months old and to 41 typically developing infants at 4, 7 and 10 months old.Results  The results suggested that the modified form continued to provide a meaningful and stable measure of cognitive functioning and revealed that DS infants may score marginally higher in terms of general cognitive abilities when using this modified form than they might when using the standard BSID‐II scales.Conclusions  This modified form may be useful for researchers who need a ‘purer’ measure with which to match infants with DS and other infants with intellectual disabilities on cognitive functioning.
Pig islet xenograft rejection in a mouse model with an established human immune system
Authors: Tonomura Noriko , Shimizu Akira , Wang Shumei , Yamada Kazuhiko , Tchipashvili Vaja , Weir Gordon C. , Yang Yong‐Guang 
Published: April 2008

Abstract:  Background:  Xenotransplantation from pigs provides a potential solution to the severe shortage of human pancreata, but strong immunological rejection prevents its clinical application. A better understanding of the human immune response to pig islets would help develop effective strategies for preventing graft rejection.Methods:  We assessed pig islet rejection by human immune cells in humanized mice with a functional human immune system. Humanized mice were prepared by transplantation of human fetal thymus/liver tissues and CD34+ fetal liver cells into immunodeficient mice. Islet xenograft survival/rejection was determined by histological analysis of the grafts and measurement of porcine C‐peptide in the sera of the recipients.Results:  In untreated humanized mice, adult pig islets were completely rejected by 4 weeks. These mice showed no detectable porcine C‐peptide in the sera, and severe intra‐graft infiltration by human T cells, macrophages, and B cells, as well as deposition of human antibodies. Pig islet rejection was prevented by human T‐cell depletion prior to islet xenotransplantation. Islet xenografts harvested from T‐cell‐depleted humanized mice were functional, and showed no human cell infiltration or antibody deposition.Conclusions:  Pig islet rejection in humanized mice is largely T‐cell‐dependent, which is consistent with previous observations in non‐human primates. These humanized mice provide a useful model for the study of human xenoimmune responses in vivo.
Characterization of porcine UL16‐binding protein 1 endothelial cell surface expression
Authors: Lilienfeld Benjamin G. , Schildknecht Anita , Imbach Lukas L. , Mueller Nicolas J. , Schneider Mårten K. J. , Seebach Jörg D. 
Published: April 2008

Abstract:  Background:  Natural killer (NK) cells participate in the immune response against solid organ allo‐ and xenografts and are tightly regulated through signals mediated by inhibiting and activating receptors expressed on their cell surface. Human NK cytotoxicity against porcine endothelial cells (pEC) is mediated by the interaction of the activating human NK receptor hNKG2D and its corresponding ligand on pEC, porcine UL‐16 binding protein 1 (pULBP1). The aim of the present study was to characterize the regulation of pULBP1 cell‐surface expression on primary porcine aortic endothelial cells (PAEC).Methods:  A monoclonal antibody (mAb; aE5‐63) directed against pULBP1 was generated by immunizing C57BL/6 mice with the pEC line PEDSV.15, and used in cellular ELISA to determine pULBP1 cell surface expression. PAEC were either left untreated or stimulated with human or porcine cytokines [interferon gamma (IFN‐γ), tumor necrosis factor alpha (TNF‐α)], human serum, cultured under hypoxic conditions, or infected with human or porcine cytomegalovirus (CMV).Results:  Neither human nor porcine IFN‐γ stimulation changed pULBP1 expression, whereas both human and porcine TNF‐α stimulation as well as human and porcine CMV infection significantly decreased pULBP1 expression on PAEC. Coculture of PAEC with human serum strongly increased pULBP1 expression depending on the binding of human anti‐pig antibodies. Exposure of PAEC to hypoxia only slightly increased pULBP1 expression.Conclusions:  In conclusion, (i) the novel anti‐pULBP1 IgM mAb aE5‐63 represents a useful tool to study pULBP1/hNKG2D‐mediated responses in xenotransplantation, and (ii) the expression of pULBP1, a human‐pig cross‐species functional hNKG2D ligand, on the surface of PAEC is modulated by various stimuli associated with transplantation.
Preparation of highly concentrated and white cell‐poor platelet‐rich plasma by plateletpheresis
Authors: Zimmermann R. , Reske S. , Metzler P. , Schlegel A. , Ringwald J. , Eckstein R. 
Published: April 2008

Background and Objectives  Contaminating white blood cells (WBC) contribute remarkably to the overall growth factor content of locally applicable platelet‐rich plasma (PRP) or platelet (PLT) gel and change the relative proportions of the contained growth factors.Materials and Methods  To study the independent effects of locally applicated highly concentrated PLTs, the development of preparations is needed that contain large amounts of PLTs and no or at least very few leucocytes. Therefore, 20 plateletpheresis procedures were performed in voluntary blood donors to get highly concentrated and extremely WBC‐poor plateletpheresis concentrates. The degree of spontaneous PLT activation, the PLT aggregation response to agonists and the level of the growth factor TGF‐β1 (transforming growth factor β1) were measured immediately after the donation and 1 day later.Results  The concentrates contained 1·96 ± 0·36 × 10e11 PLTs per unit in 55·2 ± 7·9 ml, respectively. In comparison to the donors’ blood, the PLT‐enrichment factor was 15·3 ± 5·4. At the same time, the concentrates contained extremely low residual numbers of WBCs (0·8 ± 3·3 × 10e3/ml). The concentration of the growth factor TGF‐β1 was 743·2 ± 243·9 ng/ml. On day 1, the PLT concentration and the TGF‐β1 content of the PLT concentrates had not decreased.Conclusions  In summary, plateletpheresis is suited to provide PRP products with higher concentrations of human platelets and platelet‐derived growth factors than previously reported PRP preparation methods but with extremely low numbers of contaminating leucocytes.