bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiplex PCR for detection of microcystins‐producing cyanobacteria from freshwater samples
Authors: Valério Elisabete , Chambel Lélia , Paulino Sérgio , Faria Natália , Pereira Paulo , Tenreiro Rogério
Published: June 2009

The aim of this study was to develop a PCR‐based method of gene‐directed multiplex PCR to rapidly identify microcystins producing cyanobacteria, regardless of their taxa, that could be applied in routine freshwater monitoring. Instead of using the amplification of only one or two mcy gene fragments, a multiplex PCR that simultaneously amplifies mcyA‐cd, mcyAB, and mcyB fragments of the microcystin gene cluster was validated with DNA from 124 cyanobacterial isolates and applied in 37 environmental samples. The toxicological status of the isolates was assessed by high‐performance liquid chromatography also used as the “gold standard” for the evaluation of multiplex mcy genes‐based PCR, where a sensitivity of 92.3% and a specificity of 100% have been obtained. For the environmental samples, a rapid protocol for their direct use in the PCR reaction has been developed and, by using ELISA results as “gold standard” for the presence of microcystins in these samples, a sensitivity of 80% and a specificity of 100% were achieved, showing that this multiplex PCR test is a rapid, reliable, and economical way of assessing the microcystin‐producing potential of cyanobacteria in freshwaters, regardless of their taxa or microcystins variant produced. © 2009 Wiley Periodicals, Inc. Environ Toxicol, 2010.
Systolic myocardial velocity alterations in the growth‐restricted fetus with cerebroplacental redistribution
Authors: Larsen L. U. , Sloth E. , Petersen O. B. , Pedersen T. F. , Sorensen K. , Uldbjerg N.
Published: June 2009

Objectives

Intrauterine growth restriction (IUGR) is associated with cerebroplacental redistribution (CPR), fetal stress and poor outcome, all of which may be related to dysfunction of the fetal myocardium. The aim of this study was to specifically assess myocardial function in IUGR fetuses with CPR in comparison with normal fetuses using color Doppler myocardial imaging (CDMI).

Methods

CDMI was used to evaluate and compare myocardial velocities in the left and right ventricles in normal fetuses and in IUGR fetuses with CPR. Peak systolic tissue velocities (S′) were acquired from both ventricular free walls in 20 IUGR fetuses (gestational age at scan ranged from 26 + 1 to 34 + 6 weeks, with serial measurements obtained in nine) and 42 normal fetuses (35 at week 28, with the remaining seven undergoing serial scans every 4 weeks, ranging from 18 + 6 to 39 + 1 weeks). Umbilical artery (UA), middle cerebral artery (MCA) and ductus venosus (DV) flows were also recorded.

Results

Left and right S′ increased with gestational age in normal pregnancy. Fetuses with IUGR and CPR had lower left ventricular S′ than normal fetuses (mean, 2.41 (95% CI, 1.96–2.86) cm/s vs. 3.30 (95% CI, 3.05–3.55) cm/s; P = 0.0006). This reduction in S′ correlated with the grade of UA flow abnormality (P = 0.0002). Fetuses with reversed diastolic UA flow had significantly lower left S′ (mean, 2.0 (95% CI, 1.4–2.6) cm/s; P = 0.001) than normal fetuses. There was no correlation between left S′ and MCA pulsatility index (P = 0.37) in the IUGR‐CPR group, but there was a reduction in S′ approaching statistical significance in fetuses with reversed DV flow in comparison to those without it (P = 0.09). Right S′ was similar in the two study groups and did not correlate with worsening UA flow class. All fetuses with a left S′ below 1.6 cm/s and reversed UA flow died in the perinatal period.

Conclusions

CDMI facilitates acquisition of fetal myocardial ventricular S′. The combination of IUGR and CPR is associated with a reduced left ventricular S′, especially in those with reversed UA flow. In this subgroup a left S′ below 1.6 cm/s seemed to predict mortality in the perinatal period. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
Hydrothermal Synthesis and Structural Study of an InIII Complex Involving In‐situ Decarboxylation
Authors: Song Yong‐Juan , Zhao Peng‐Cheng , Zhang Peng , Han Zheng‐Bo
Published: June 2009

The hydrothermal reaction of indium chlorine, 2,2’‐bipyridine, and 2,3‐pyrazinedicarboxylic acid leads to the generation of a mononuclear InIII complex, [In(bpy)(Cl)2]Cl·0.5pz·H2O (1) (bpy = 2,2’‐bipyridine, pz = pyrazine). X‐ray diffraction analysis indicates that compound 1 crystallizes in the orthorhombic system Pbca space group with a = 12.667(3) Å, b = 15.269(3) Å, c = 15.859(3) Å, V = 3067.4(11) Å3 and Z = 8. These discrete units are linked by the hydrogen bondings and C···H–π stacking interactions to form a 3D network. It is interesting to find that the in situ decarboxylation of 2,3‐pyrazinedicarboxylic acid into pz ligand was observed.
A Novel μ2‐(H2O)‐Bridged Double‐Chain Coordination Polymer [Cd(pc)(phen)(H2O)]n with Rhombic Grids (H2pc = pamoic acid, phen = 1,10‐phenanthroline)
Authors: Han Guang‐Xi , Song Yong‐Juan , Zhao Peng‐Cheng , Chen Xia , Han Zheng‐Bo
Published: June 2009

A novel coordination polymer [Cd(pc)(phen)(H2O)]n (H2pc = pamoic acid, phen = 1,10‐phenanthroline) has been synthesized under hydrothermal conditions. Single crystal X‐ray diffraction analysis reveals that the compound crystallizes in triclinic space group P1. All the CdII atoms in the compound are hexacoordinate and are linked by pamoicate ligands to form a one‐dimensional zigzag chain. Furthermore, two adjacent zigzag chains are connected by the μ2‐(H2O) molecules to form a double‐chain with rhombic grids. There exist intermolecular C–H···π contacts, π–π stacking and hydrogen‐bonding interactions. Compound 1 displays strong fluorescent emission in the solid state at room temperature.
[Bis(tetrahydrofuran–O)–bis(1,3–dialkyl–2–diphenylphosphanyl–1,3–diazaallyl)calcium] – Synthesis and Crystal Structures of Calcium Bis[phospha(III)guanidinates] and Investigations of Catalytic Activity
Authors: Al–Shboul Tareq M. A. , Volland Gritt , Görls Helmar , Westerhausen Matthias
Published: June 2009

The reaction of [(thf)4Ca(PPh2)2] (1) with diisopropyl– and dicyclohexylcarbodiimides yields the phospha(III)guanidinates [(thf)2Ca{RNC(PPh2)NR}2] with R = isopropyl (2) and cyclohexyl (3). The metathesis reaction of K{RNC(PPh2)NR} with anhydrous CaI2 also allows the synthesis of these phospha(III)guanidinate complexes 2 and 3. For 2 a cis arrangement is observed whereas 3 crystallizes as trans isomer. The phospha(III)guanidinates act as bidentate chelate bases with an average Ca–N distance of 242.5 pm. The C–P bond length between the PPh2 fragment and the 1,3–diazaallyl unit is with values above 190 pm very large. The complexes 2 and 3 show a moderate catalytic activity in hydrophosphanylation reactions of dialkylcarbodiimides with diphenylphosphane.
A Pilot Study to Assess the Feasibility of a Multicenter Cluster Randomized Trial for the Management of Asymptomatic Persons with a Thrombophilia
Authors: Wells Philip S. , Louzada Martha L. , Taljaard Monica , Anderson David R. , Kahn Susan R. , Langlois Nicole J. , Rutberg Julie , Kovacs Michael J. , Rodger Marc A.
Published: June 2009

There is controversy whether asymptomatic first‐degree relatives (FDRs) of patients with venous thromboembolism (VTE) and thrombophilia should be screened, followed, and prescribed prophylaxis during risk periods. We recruited consecutive probands with idiopathic VTE and thrombophilia from our thrombosis clinics. Those FDRs with thrombophilia were randomized in family clusters to receive one‐time verbal counseling and no organized follow‐up or counseling, educational material, reminder aids and follow‐up. Only 203 of 1,129 FDRs were eligible and consented. Dropouts were common; 1 FDR (1.7%) developed VTE. VTE risk, ability to treat and prevent were underestimated by the participants. Patients with VTE and thrombophilia and their FDRs are often not interested in thrombophilia testing. Despite education to inform their knowledge, interest and follow‐up were less than ideal. The question of the best educational approach in these patients remains unanswered. The value of testing and following asymptomatic carriers of probands with VTE and thrombophilia remains unknown.
Improved bracing compliance in children with clubfeet using a dynamic orthosis
Authors: Garg Sumeet , Porter Kristina
Published: June 2009

Purpose

Non-compliance with foot abduction bracing in children with clubfeet treated with the Ponseti method is the leading risk factor for deformity recurrence. A dynamic foot abduction orthosis is believed to result in improved compliance, fewer skin complications, and fewer recurrences. A case–control trial was conducted to test this hypothesis.

Methods

A prospective cohort of children with idiopathic clubfoot using a dynamic brace was compared to a historical control group treated with a standard orthosis. Compliance, skin complications, recurrence, and the need for surgical soft tissue release were compared between groups at equivalent follow-up.

Results

The dynamic and standard brace groups are equivalent in age at the start of treatment (1.9 vs. 2.9 months), number of affected feet (97 vs. 92), and severity (average of four casts required for correction in each group). Fifty-seven children were followed in each group for an average of 2 years. All were corrected initially with the Ponseti method. Compliance is higher using the dynamic brace (47/57, 81%) compared to the standard brace (21/57, 47%) ( P < 0.001). The recurrence rate is lower using the dynamic brace (11/57, 19%) compared to the standard brace (22/57, 39%) ( P < 0.02). Skin complications are fewer in the dynamic brace (2/57, 3%) compared to the standard brace (11/57, 19%) ( P < 0.008). Most importantly, five children using the standard brace underwent posteromedial release within 2 years of treatment, compared to none in the dynamic brace group.

Conclusion

The dynamic foot abduction brace results in improved compliance, fewer recurrences, fewer skin complications, and reduced rates of surgery in idiopathic clubfoot than the traditional brace after non-operative correction with the Ponseti method.
A new Parametopella species (Crustacea: Amphipoda: Stenothoidae) from Antholoba achates (Anthozoa: Actiniaria) from Coquimbo, Chile (with remarks on Parametopa alaskensis (Holmes))
Authors: Krapp-Schickel Traudl , Vader Wim
Published: June 2009

This paper describes a new species in the genus Parametopella (Amphipoda: Stenothoidae), P. antholobae sp. nov., collected among the tentacles of the sea anemone Antholoba achates, found in shallow water near Coquimbo, Chile. A key to all Parametopella species is provided. The type specimen of the superficially similar species Parametopa alaskensis (Holmes) was studied; that species remains in Parametopa.
Ecobiological survey of the brine shrimp Artemia salina from Sabkhet El Adhibet (south-east Tunisia)
Authors: Ben Naceur Hachem , Ben Rejeb Jenhani Amel , Romdhane Mohamed Salah
Published: June 2009

In order to provide a better characterization and understanding of the brine shrimp Artemia salina life-cycle, different ecological and biological parameters were taken out monthly during two periods from November 2005 to April 2006 and from November 2006 to April 2007 in Sabkhet El Adhibet (south-east Tunisia). Variation of water temperature, salinity, pH, dissolved oxygen, nutrients (orthophosphate, nitrites, nitrates and ammonium) and phytoplankton density were monitored. The Artemia population was also surveyed. Artemia were present in the site with salinity between 32.2 and 281.7 g l−1 and water temperature between 12.1 and 25.4°C. The pH ranged from 7.6 to 9 and dissolved oxygen concentration from 3.4 to 17.5 mg l−1. Minimum and maximum values of phytoplankton density were 0.19 and 14.59 106 cell l−1. In addition, the nutrient analysis registered showed that nitrate and ammonium represent the major nutrient. The Artemia population density fluctuated between 0.22 and 38.57 individuals per litre. The male:female ratio was dominated by the males. Artemia from Sabkhet El Adhibet showed variability in fecundity (total offspring and brood size) as well as in the ratio encystment/oviviparity. The individual fecundity fluctuates between 29.4 and 70.2 cysts and 17.8 and 69.8 nauplii. Finally, the influence of physical and chemical parameters as well as phytoplankton density over the Artemia population was noticed.
Differential effects of α-helical and β-hairpin antimicrobial peptides against Acanthamoeba castellanii
Authors: SACRAMENTO R. S. , MARTINS R. M. , MIRANDA A. , DOBROFF A. S. S. , DAFFRE S. , FORONDA A. S. , DE FREITAS D. , SCHENKMAN S.
Published: June 2009

In this work we evaluated the ability of different types of antimicrobial peptides to promote permeabilization and growth inhibition of Acanthamoeba castellanii trophozoites, which cause eye keratitis. We used cationic α-helical peptides P5 and P6, corresponding to the N-terminus of the pore-forming protein from Triatoma infestans, a blood-sucking insect, and a β-hairpin amphipathic molecule (gomesin), of the spider Acanthoscurria gomesiana haemocytes. A. castellanii permeabilization was obtained after 1 h incubation with micromolar concentrations of both types of peptides. While permeabilization induced by gomesin increased with longer incubations, P5 permeabilization did not increase with time and occurred at doses that are more toxic for SIRC cells. P5, however, at doses below the critical dose used to kill rabbit corneal cells was quite effective in promoting growth inhibition. Similarly, P5 was more effective when serine protease inhibitor was added simultaneously to the permeabilization assay. High performance chromatography followed by mass spectrometry analysis confirmed that, in contrast to gomesin, P5 is hydrolysed by A. castellanii culture supernatants. We conclude that the use of antimicrobial peptides to treat A. castellanii infections requires the search of more specific peptides that are resistant to proteolysis.
Early CD44hiCD4+and CD44hiCD8+T cell numbers and the absence of mannose-rich glycoconjugates determine the protective outcome of anti-leishmanial immunity
Authors: KEDZIERSKI L. , CURTIS J. M. , KEDZIERSKA K.
Published: June 2009

Vaccination remains the best hope for control of all forms of leishmaniasis, and the development of a safe and effective vaccine is a critical global public-health priority. Our previous work showed that immunization with non-persistent phosphomannomutase-deficient (ΔPMM)Leishmania majorparasites confers significant protection in susceptible BALB/c mice due to increased T-cell numbers and suppression of IL-10 and IL-13 early during infection. Here, we complemented the ΔPMML. majorparasites with human PMM2 to determine whether we could further improve the protection. Complemented ΔPMM parasites have restored glycoconjugate biosynthesis, while retaining avirulence of the parental knockout strain. Immunization with hPMM2 add-back parasites showed similar Th1/Th2 cytokine profiles to that observed in ΔPMM-vaccinated mice. However, the numbers of the activated CD4+CD44hiand CD8+CD44hiT cells recruited to the draining lymph nodes early afterLeishmaniainfection were reduced, leading to decreased protection following hPMM2-immunization. Thus, the magnitude of T-cell responses early in the infection and the absence of mannose-rich glycoconjugates determine the protective outcome of anti-leishmanial immunity.
Introduction: Poetics and Politics of the Future: Reverberations and Continuations of Cultural Practices from Jewish/Israeli and German Perspectives
Authors: FISCHER-LICHTE ERIKA , WEILER CHRISTEL
Published: June 2009

This introduction outlines the ongoing research project (see title) jointly pursued by the theatre departments of Tel Aviv University and Freie Universität Berlin funded by the German-Israeli Foundation for Scientific Research and Development (GIF). The project pivots around two critical questions. First, how can we investigate and conceptualize the future as a theoretical category and temporal dimension with regard to performances? Second, what themes and tools can articulate the various directions for developing and negotiating political and poetic questions of identity, artistic creation, cultural transference and conceptions of the ‘other’ in and through performance in and for the future? The introduction delineates certain theoretical reflections that serve as a scaffold for meaningful investigations into the first question. The theories are tested by the following fourteen articles that analyse and reference a variety of performances and in this way highlight their particular future-oriented (indeed future-generating) qualities.
The Potential of the End(ing): Anticipated Nostalgia in To the Dogs by Lone Twin
Authors: TECKLENBURG NINA
Published: June 2009

The following article examines the functions and the effects of the process of setting an ending. The performance To the Dogs by the English performance duo Lone Twin stages its end(ing) by interlinking two phenomena which have often been separated in theatre criticism: the theatrical event – seen as something happening in the present – and narrative – considered as something belonging to the past. In To the Dogs the event is narrativized by the performers as it goes along, providing it with endings on the level of rhetoric, content and time structure. In this process the performance is transformed into a myth, in which the event is anticipated as a closed story, even though it is still about to happen. This future-poetics of the end(ing), in which a collective event, paradoxically, is being charged in advance with nostalgia, illustrates the affective force of a (narrative) ending as performance. It does so not only in a negative, restrictive sense of closing the event as story, but also in a positive, enabling sense: To the Dogs raises the question of how far the discourse about an event regarded as unique and inaccessible implies a narrative quality. The process of setting a future ending is revealed as being more than a generator of narrative closure; this essay aims to perform the fact that it is also an enabling moment of opening the seemingly closed event as myth into a time afterwards.
Potential Life: Modelling the Void in Two Productions ofThe Cherry Orchard
Authors: BEN-SHAUL DAPHNA
Published: June 2009

This paper examines the different meanings of the monochromatic principle and the act of voiding in two productions ofThe Cherry Orchard– Georgio Strehler's renowned, predominantly white production (1974) and an Israeli production directed by Yevgeny Arye at the Gesher Theater in Tel Aviv (2006), in which a white canopy hung over the stage. In both cases, the perception of the space negates the independent reality of the place, shaping it rather as a potential space. The visual formation that realizes the principle of potentiality – in any production, in any variation – is used as a ground on which mental and imaginary projections are cast. Characters acting in such a space are, to use Bloch's terms, in a state of ‘not yet’ – expecting and hoping to realize their potential lives. In addition, the stage space is constructed in both productions, albeit in different ways, as an intermediate space – a potential space, in Winnicott's terms – that is filled up with transitional objects and games. Chekhov's characters exist in the gap between mergence with the object and separation of the subject, and thus also between past and future. Suspension of the reality principle and pseudo-liberation from its realization are a psychoanalytic version of utopia. Such an existence is utopian also by dint of being an ideological model based – contrary to our sociopolitical realities – on subject–object unity, radically expressed by means of the dominant white monochrome.
‘The Fall of God into Meaning’: Painting Time in Jacob Wrestling with the Angel
Authors: GAL NISSIM
Published: June 2009

The future as an event cannot be analysed solely through its simple relation to the known or recognized world, but through its unexpected dimensions: its being beyond history and the way it performs commandments and ethical obligations. Two visual interpretations of the biblical story of Jacob Wrestling with the Angel, by Eugène Delacroix and Paul Gauguin, are at the centre of my discussion. The main theoretical tool for discussing the issues of time and the future is the philosophical writing of Emmanuel Levinas.
Given the Tino Sehgal Case: How to Save the Future of a Work of Art that Materializes Only Temporarily
Authors: UMATHUM SANDRA
Published: June 2009

This article focuses on German artist Tino Sehgal (born in 1976), whose works of art materialize only temporarily, while they fulfill, at the same time, all the requirements that any work of the visual arts must fulfill if it is to have a lasting existence. In this regard Sehgal's artistic approach not only takes a unique position within the history of art; it also departs fundamentally from the tradition of performance art. This article deals with the way Sehgal tries to save the future of the ephemeral situations his art puts forth, and shows, furthermore, how he thereby confronts questions and problems that performance art has neglected or even generated.
Retinotopic representation of the bifoveate eye of the kestrel (Falco sparverius) on the optic tectum
Authors: Frost B. J. , Wise L. Z. , Morgan B. , Bird D.
Published: June 2009

Like many diurnal raptors, the American kestrel or sparrow hawk, Falco sparverius, possesses two foveae in each eye. In this study, we used fundus photography and reversed ophthalmoscopy to plot the projection of these foveae onto the visual field, together with other retinal landmarks such as the pecten and ora terminali. From such data, it was determined that the central monocular fovea (CMF) and temporal binocular fovea (TBF) were separated by 36 deg and that the kestrel has 58 deg of binocular overlap when the eyes are appropriately converged. Single-cell and multi-unit recordings were used to systematically explore the tectal surface and map receptive fields (RF) onto a hemispheric screen. A retinotopic map of the tectal surface was produced from such data and revealed an expanded representation for each fovea on the tectum and a systematic increase in RF size from fovea to periphery. The functional significance of this organization is discussed.
Development of flash-evoked responses in the ectostriatum of the zebra finch: An evoked potential and current-source-density analysis
Authors: Engelage J. , Bischof H.-J.
Published: June 2009

The morphological development of the tectofugal pathway in the zebra finch has recently been described in a series of studies from our laboratory. No data are currently available on the development of visual responsiveness in this pathway. We therefore investigated the development of visually evoked potentials (VEPs) in the ectostriatum, the telencephalic target area of the tectofugal pathway. Contralateral VEPs could already be recorded in 20-day-old birds, whereas ipsilateral VEPs could first be recorded in 40-day-old birds. The latencies of contralateral VEPs decrease to adult values between 20 and 40 days of age, probably due to an increase in the myelination of afferent fibers. The amplitudes of the contralateral VEPs increase continuously from day 20 to day 60; however, between 60 and 80 days of age the responses diminish substantially (−60%). Thus, contralateral VEPs in 80-day-old birds are not significantly different from those in 20-day-old birds. Thereafter the responses recover and reach their final amplitude values at about 150 days of age. The relationship of these results to morphological studies and possible mechanisms which may cause the double-peaked development of visual-evoked potentials in the ectostriatum are discussed.
Development of geniculocortical axon arbors in a primate
Authors: Florence S. L. , Casagrande V. A.
Published: June 2009

The main objective of the present study was to describe the postnatal development of magnocellular and parvocellular LGN axons within the primate striate cortex. For this purpose, we bulk labeled axons in neonatal prosimians (galagos) in vivo or in vitro at regular intervals from birth (PO) to 12 weeks after birth by injecting horseradish peroxidase (HRP) into white matter anterior to the striate cortex. Filled axons within layer IV were reconstructed, quantitatively analyzed, and compared to a population of adult axons described previously (Florence & Casagrande, 1987).

Our results show that although axons are morphologically immature at birth, they are restricted to the upper (IVα) and lower (IVβ) tiers of layer IV of the striate cortex as in adults. In adults, we referred to the presumed magnocellular LGN axons terminating in IVα as type I and the presumed parvocellular axons terminating in IVβ as type II. We used the same convention for developing axons.

From birth to 3 weeks postnatal, type I and II axon classes are more variable in appearance than adult counterparts, and are not morphologically class distinct. As axons mature, parent axon shafts increase in caliber, arbors become smaller and more radial, and other immature features (e.g. spikes, protrusions, growth cones) are less evident. Both arbor classes mature slowly and some still exhibit immature features (e.g. growth cones) as late as 12 weeks postnatally. Although arbors do not show class-distinctive features until late in development, each class does show some unique maturational trends. Type I arbors are only slightly larger than adult counterparts at birth, whereas type II arbors are dramatically larger. Type I arbors increase in branch complexity with age, whereas type II arbors simply show a shift in complexity toward the center of the arbor with decreasing size over time. These growth trends suggest that magnocellular and parvocellular pathways to cortex could be differentially vulnerable to the manipulation of postnatal visual experience.
A quantitative measure of the electrical activity of human rod photoreceptors using electroretinography
Authors: Hood Donald C. , Birch David G.
Published: June 2009

An eletrical potential recorded from the cornea, the a-wave of the ERG, is evaluated as a measure of human photoreceptor activity by comparing its behavior to a model derived fromin vitrorecordings from rod photoreceptors. The leading edge of the ERG exhibits both the linear and nonlinear behavior perdicted by this model. The capability for recording the electrical activity of humans photoreceptors inin vivoopens new avenues for assessing normal and abnormal receptor activity in humans. Furthermore, the quantitative model of the receptor response can be used to isolate the inner retinal contribution, Granit's PII, to the gross ERG. Based on this analysis, the practice of using the trough-to-peak amplitude of the b-wave as a proxy for the amplitude of the inner nuclear layer activity is evaluated.
Colocalization of substance P and GABA in retinal ganglion cells: A computer-assisted visualization
Authors: Caruso Daniel M. , Owczarzak Michael T. , Pourcho Roberta G.
Published: June 2009

Ganglion cells in the albino rat retina were retrogradely labeled with the fluorescent dye, diamidino-yellow, from the superior colliculus. Preembedding and postembedding immunocytochemical techniques were employed in conjunction with computer-assisted image processing to visualize SP- and GABA-immunoreactivity. Examination of flatmount and sectioned retinas revealed that approximately 3% of the ganglion cells projecting to the contralateral superior colliculus exhibit SP-immunoreactivity. Moreover, these cells were found to comprise a subpopulation of the GABA-immunoreactive cells projecting to the rat tectum.
Contribution of quisqualate/ kainate and NMDA receptors to excitatory synaptic transmission in the rat's visual cortex
Authors: Nishigori A. , Tsumoto T. , Kimura F.
Published: June 2009

Actions of antagonists for excitatory amino-acid (EAA) receptors on extracellularly and intracellularly recorded responses of layer II/III cells to electrical stimulation of the underlying white matter were studied in a slice preparation of rat's visual cortex. Antagonists used were 2-amino-5-phosphonovalerate (APV) and 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), which are selective antagonists for EAA receptors of N-methyl-D-aspartate (NMDA) and quisqualate/kainate (non-NMDA) type, respectively. In extracellular recordings, it was found that responses of almost all of the cells were suppressed by CNQX. In contrast, sensitivity to APV was different between cells with short- and long-latency responses; 81% of the former responses were not suppressed by APV, while about a half of the latter were suppressed. Excitatory postsynaptic potentials (EPSPs) evoked by white-matter stimulation were recorded intracellularly from 42 neurons. Most of polysynaptically elicited EPSPs were sensitive to APV, whereas the majority of monosynaptic EPSPs were not. CNQX almost completely suppressed EPSPs irrespective of monosynaptically or polysynaptically evoked, but in some cases slow EPSPs with low amplitude were spared. These CNQX-resistant EPSPs were elicited polysynaptically and had an anomalous voltage dependence, a characteristic of NMDA receptors. It is suggested that non-NMDA receptors contribute dominantly to first-order synaptic transmission while NMDA receptors participate substantially in second-order transmission so as to serve as a booster of outputs from visual cortex.
Green-sensitive cone photoreceptors are selectively labeled by Procion yellow dye in goldfish retina
Authors: Petry Heywood M. , Bassi Carl J.
Published: June 2009

Selective labeling of intravitreal Procion yellow dye by presumed blue-sensitive cone photoreceptors has been demonstrated in primate retina. To determine whether Procion yellow is selective for this cone type in an unrelated vertebrate species, labeling by this dye was studied in goldfish retina, where cone pigment type can be directly inferred from photoreceptor morphology. At low vitreal concentrations of the dye (<0.4%), only cone outer segments were labeled. At vitreal concentrations of 0.4–0.5%, the inner segments of short-double cones and a subset of long single cones (presumed green-sensitive cones) were selectively stained. At still higher vitreal concentrations (0.6–0.7%), the inner segments of short-single cones and miniature short-single cones (presumed blue-sensitive cones) showed evidence of Procion label, but were not as heavily labeled. The inner segments of long-double cones and a subset of long-single cones (presumed red-sensitive cones) did not label at any of these concentrations. These results show that Procion yellow is not a selective marker for blue-sensitive cones in the goldfish retina. In addition, stained rod and cone nuclei were observed at each dye concentration, including those concentrations at which no inner segments were labeled.
An unusual voltage-gated anion channel found in the cone cells of the chicken retina
Authors: Wilson Martin , Gleason Evanna
Published: June 2009

Using the whole-cell patch clamp technique, we have examined the voltage-gated currents present in adult chicken cone cells. When calcium and calcium-gated currents are blocked, hyperpolarizing voltage steps elicit slowly increasing inward currents as has been shown for photoreceptors in other species. Unlike the case for other species, chicken cones appear to lack the inward-rectifying cationic current Ih that contributes to the shaping of the photovoltage. Instead of Ih, these cones possess an anionic inward-rectifying current that in kinetics, activation range and probably function is remarkably similar to Ih. This anion channel is unusual in that both nitrate and acetate are more permeant than chloride ions.
Neural organization of the retina of the turtleMauremys caspica:a light microscope and Golgi study
Authors: Kolb Helga , Perlman Ido , Normann Richard A.
Published: June 2009

The organization of the retina of the turtle speciesMauremys caspica, found in fresh water ponds of Israel, has been examined by light microscopical techniques including examination of fresh wholemount retina, one micron blue-stained vertical sections and Golgi-stained material. The anatomical findings onMauremysretina have been compared with those of thePseudemysretina (Kolb, 1982) which is more commonly used for electrophysiological and neurochemical studies in the USA. The photoreceptors ofMauremysare similar in type and oil droplet content toPseudemysphotoreceptors except for the double cone inMauremys.This cone type appears more abundant than inPseudemysand the principal member contains a yellow oil droplet instead of an orange oil droplet. Golgi staining reveals that all the cell types that have been seen inPseudemysare found inMauremyswith identical morphology. In addition, two amacrine cell types that were not before described forPseudemyshave been added to the classification. One of these is the tristratified dopaminergic amacrine cell described in immunocytochemical studies (Witkovsky et al., 1984; Nguyen-Legros et al., 1985; Kolb et al., 1987). We have used these anatomical studies onPseudemysandMauremysretina to form a catalogue of neural types for the turtle retina in general. We conclude with an attempt to combine findings from anatomy, electrophysiology, and neurochemistry to form an overview of the organization of this reptilian retina.
Prenatal disruption of binocular interactions creates novel lamination in the cat's lateral geniculate nucleus
Authors: Garraghty Preston E. , Shatz Carla J. , Sur Mriganka
Published: June 2009

The elimination of retinogeniculate afferents from one eye on embryonic day 44 (E44) has pronounced effects on the formation of the cellular laminae in the cat lateral geniculate nucleus (LGN). Only two laminae form: a dorsal, “magnocellular” layer, and a ventral, “parvocellular” layer. Soma size measurements and previously reported patterns of termination of retinogeniculate axons suggest that the dorsal lamina is a coalescence of the normal A-laminae and the dorsal, magnocellular division of layer C, while the ventral layer is a composite of the parvocellular sublamina of layer C and the remaining C-laminae. This is a novel pattern of lamination in the LGN that differs from that found in the normal nucleus, not only in that there are now only two cell layers rather than the normal five, but also in that the interlaminar zone occurs in an abnormal location. This result is markedly different from that observed in other species where interlaminar zones present after early monocular enucleation are a subset of the ones which would normally be present. We suggest that, in the absence of ongoing binocular interactions, interactions between functionally distinct retinal ganglion cell classes from the remaining eye may direct the formation of cell laminae in the LGN, even when such interactions are not normally operative.
Distribution and size of ganglion cells in the retinae of large Amazon rodents
Authors: Silveira L. C. L. , Picanço-Diniz C. W. , Oswaldo-Cruz E.
Published: June 2009

The topographical distribution of density and soma size of the retinal ganglion cells were studied in three species of hystricomorph rodents. Flat-mounted retinae were stained by the Nissl method and the ganglion cells counted on a matrix covering the whole retinae. Soma size was determined for samples at different retinal regions. The agouti, a diurnal rodent, shows a well-developed visual streak, reaching a peak density of 6250 ganglion cells/mm2. The total number of ganglion cells ranged from 477, 427–548, 205 in eight retinae. The ganglion-cell-size histogram of the visual streak region exhibits a marked shift towards smaller values when compared to retinal periphery. Upper and lower regions differ in both cell density and cell size. The crepuscular capybara shows a less-developed visual streak with a peak ganglion cell density of 2250/mm2. The shift towards small-sized cells in the visual streak is less marked. Total ganglion cell population is 368,840. In the nocturnal paca, the upper half of thefundus oculiincludes atapetum lucidum. The retina of this species shows the least-developed visual streak of this group, with the lowest peak ganglion cell density reaching 925/mm2. The total ganglion cell number (230,804) is also smaller than in the two other species. Soma-size spectra of this species are characterized by the presence, in the lower hemi-retina, of very large perikarya comparable in size to the cat's alpha ganglion cells.
Differential effects of excitatory amino acids on photoreceptors of the chick retina: An electron-microscopical study using the zinc-iodide-osmium technique
Authors: Sattayasai Jintana , Zappia Joe , Ehrlich David
Published: June 2009

Although excitotoxins derived from acidic amino acids are known to damage neurons in the inner nuclear and ganglion cell layers of the retina, little is known about their effects on photoreceptors. This study examines the acute and long-term effects of excitotoxins on photoreceptors of the chick retina. The zinc-iodide-osmium (ZIO) technique, which darkly labels a substantial subpopulation of synaptic vesicles in normal photoreceptor terminals, was used to supplement routine electron microscopy. Two-day-old chicks received a single intraocular injection of either 10, 50, or 200 nmoles kainic acid (KA), 200 nmoles N-methyl-D-aspartic acid (NMDA), or 200 nmoles quisqualic acid (QUIS), and were allowed to survive for either 6 h, 7 d, or 21 d. At 6 h, following exposure to 10, 50, and 200 nmoles KA, there was swelling and disruption of photoreceptor lamellae of the outer segments. At 7- and 21-d survival, 50 and 200 nmoles KA resulted in rounded, condensed synaptic terminals, which contained a high density of synaptic vesicles. However, there was complete loss of ZIO-positive vesicles within these photoreceptors. Outer segments were still disrupted, although small patches of lamellae were evident, suggestive of regeneration. Following exposure to QUIS, there was extensive swelling of outer segment lamellae at 6 h survival. Synaptic ribbons in terminals were also swollen. At longer survival periods, QUIS exposure resulted in a reduction of ZIO-positive vesicles, as well as swollen lamellae in outer segments. NMDA exposure, at either short or long-term survival, did not alter photoreceptor morphology, including the pattern of ZIO stain. The prolonged effects of KA, and to a lesser extent QUIS, on photoreceptors suggests that these drugs have a long-term effect on photoreceptor function. The ZIO technique provides a novel and potentially useful approach for identification of damaged photoreceptors.
Projections of the nucleus of the optic tract to the nucleus reticularis tegmenti pontis and prepositus hypoglossi nucleus in the pigmented rat as demonstrated by anterograde and retrograde transport methods
Authors: Korp Barbara G. , Blanks Robert H. I. , Torigoe Yasuhiro
Published: June 2009

The visual pathways from the nucleus of the optic tract (NOT) to the nucleus reticularis tegmenti pontis (NRTP) and prepositus hypoglossi nucleus (ph) were studied following injections of tritiated leucine into the NOT of pigmented rats. The cell bodies of origin of the pretectal-NRTP, NRTP-ph, and pretectal-ph projections were determined using retrograde horseradish peroxidase (HRP) technique.

The pretectum projects strongly to the rostral two-thirds of the central and pericentral subdivisions of the NRTP and sends a remarkably smaller projection to the ph. Both are entirely ipsilateral. The fibers destined for the ph travel with the NOT-NRTP bundle, pass through the NRTP, traverse the medial longitudinal fasciculus, and are distributed to the rostral one-half of the ph. The retrograde HRP studies confirm these pathways. The pretectal projections to the NRTP arise from neurons in the rostromedial NOT; those to the ph are located primarily in the rostral NOT although small numbers are found within the anterior, posterior, and olivary pretectal nuclei. Of major importance is the fact that the ph injections retrogradely label neurons within the NRTP and the adjacent paramedian pontine reticular formation. This NRTP-ph projection is entirely bilateral and arises from parts of both subdivisions of the nucleus targeted by NOT afferents.

Both the direct NOT-ph and indirect NOT-NRTP-ph connections provide the anatomical basis for the relay of visual (optokinetic) information to the perihypoglossal complex and, presumably, by virtue of reciprocal ph-vestibular nuclear connections, to the vestibular nuclei itself. Such pathways confirm previous physiological studies in rat and, in particular, clarify the contrasting effects of electrolytic lesions of NRTP in rat which completely abolishes optokinetic nystagmus (OKN) (Cazin et al., 1980a) vs kainic acid lesions which produce only minor effects on OKN slow velocity (Hess et al., 1988). Given these differential effects, one concludes that the critical pathway for OKN passes in relation to, but is not significantly relayed by, the neurons of the NRTP or adjacent pontine tegmentum. The present studies suggest that one such fiber system is the NOT-ph bundle. How this relatively small projection compares to other possible fiber of passage systems remains to be determined electrophysiologically.
Postnatal development of neuropeptide Y-like immunoreactivity in area 17 of normal and visually deprived rhesus monkeys
Authors: Tigges Margarete , Tigges Johannes , McDonald John K. , Slattery Michael , Fernandes Alcides
Published: June 2009

Immunocytochemical methods were used to examine neuropeptide Y (NPY) immunoreactive neurons and fibers in area 17 of rhesus monkeys during the first year of life. NPY-immunoreactive (+) neurons are nonpyramidal cells which are either multipolar, bipolar, or bitufted in shape. They occur most frequently in layer 6 and the subjacent white matter, are sparser in the supragranular layers, and absent from layer 4C. Labeled somata in the supragranular layers are smaller compared to those in layer 6 and the white matter. A typical axon originates from the NPY+ soma or from a primary dendrite and frequently is varicose. Distribution and morphologies of NPY+ neurons in area 17 of infants are similar to those of adult monkeys. Thus, it seems that NPY+ neurons in rhesus monkeys are mature from birth. NPY+ fibers occur in area 17 from birth; however, they differ in density and distribution from those of older infant and adult monkeys. At birth, a prominent fiber plexus is found in the deepest part of layer 1, and another in the white matter. Immunoreactive processes are sparse in the remaining cortical gray, except for some vertical fibers extending from pia to white matter. By 4 months of age, labeled fibers form a coarse network in layers 2, 3, 5, and 6. In addition, a distinct plexus extends through layers 4B, 4A, and the lowest aspect of layer 3. Also, a thin immunoreactive fiber band is found at the bottom of layer 4C. In the remainder of layer 4C, NPY+ fibers are scant. The supragranular layers also exhibit a unique immunoreactive “snarl” of fibers. Increases in density of NPY+ processes in the older infants are gradual so that between 7 and 13 months of age, NPY+ fibers appear to have achieved adultlike densities. These observations indicate that NPY+ fibers in area 17 of newborn rhesus monkeys undergo postnatal maturation which reaches a plateau around 4 months of age. After monocular visual deprivation from birth to 4 months of age, either by eyelid suture or by occlusion with an opaque contact lens, density and distribution of NPY+ neurons and fibers, including snarls, appear similar to those of age-matched undeprived infants. Thus, disruption of the normal binocular input does not seem to arrest the maturation of the NPY system in area 17 of rhesus monkeys during a sensitive period of early postnatal development.
Cone photoreceptors lacking oil droplets in the retina of the echinda,Tachyglossus aculeatus(Monotremata)
Authors: Young Heather M. , Pettigrew John D.
Published: June 2009

The echidna,Tachyglossus aculeatus, a monotreme mammal, is thought to possess an all-rod retina (O' Day, 1952). This study provides anatomical evidence for the presence of cone-like photoreceptors in the retina of the echidna. The cones, which constitute 10–15% of the photoreceptors, have all of the ultrastructural characteristics previously shown in the cones of placental mammals, and, like the cones of other animals (Blanks & Johnson, 1984), they bind peanut agglutinin. Unlike the cones of another monotreme, the platypus, the cones of the echidna retina do not possess oil droplets. Twin cones, pairs of cones in which there is no obvious difference in the size, shape, or ultrastructural features of the members of a pair, are common. The density of cones varies from 9000 cells/mm2in the superior periphery to 22,000 cells/mm2in the central retina. Nearest-neighbor analysis suggests that the cone mosaic in the echidna retina results from the presence of single and twin cones in a relatively regular array.
Evaluation of a linear model of directional selectivity in simple cells of the cat's striate cortex
Authors: Tolhurst D. J. , Dean A. F.
Published: June 2009

We have compared the responses of simple cells to laterally moving sinusoidal gratings and to stationary temporally-modulated gratings. From the amplitudes and temporal phases of the responses to stationary gratings of different spatial phases, it should be possible to predict the preferred direction of movement, the amplitudes of the responses to gratings moving in the preferred and nonpreferred directions and, thence, the degree of directional preference (Reid et al., 1987). The preferred direction can be predicted reliably. However, the magnitude of the directional preference cannot be predicted, since the measured amplitude of the response in the nonpreferred direction of movement is very much less than that predicted by a linear theory. Nonlinearities in the relationship between response amplitude and contrast may contribute to the failure of the predictions, but this contribution is small. We conclude that the magnitude of the directional preference seems to be determined predominantly by nonlinear suppression of the response in the nonpreferred direction of movement.
Effects of ectostriatal lesions on natural concept, pseudoconcept, and artificial pattern discrimination in pigeons
Authors: Watanabe Shigeru
Published: June 2009

Pigeons were trained on four different visual discrimination tasks: (1) concept of natural stimuli (food vs. non-food object discrimination); (2) arbitrary classification of natural stimuli (pseudoconcept); (3) concept of artificial stimuli (triangles generated by computer graphics); and (4) discrimination of one pair of artificial stimuli. Then, lesions of the ectostriatum were carried out. The ectostriatal lesions impaired the arbitrary classification of natural stimuli and the concept of artificial pattern but did not impair the natural concept or the simple discrimination of fixed two stimuli. Lesions in the neostriatum did not cause deficits in any discrimination task. The birds had to learn individual stimuli for the arbitrary classification of stimuli and the stimulus generalization test after the artificial pattern concept discrimination indicated that the pigeons formed a concept more complicated than “triangle” in human language. These results suggest that the ectostriatum plays a role in task discrimination that requires much visual processing to classify stimuli.