Correlates of support for international vaccine solidarity during the COVID-19 pandemic: Cross-sectional survey evidence from Germany

During the COVID-19 pandemic, many residents of high-income countries (HICs) were eligible for COVID-19 vaccine boosters, while many residents of lower-income countries (LICs) had not yet received a first dose. HICs made some efforts to contribute to COVID-19 vaccination efforts in LICs, but these efforts were limited in scale. A new literature discusses the normative importance of an international redistribution of vaccines. Our analysis contributes an empirical perspective on the willingness of citizens in a HIC to contribute to such efforts (which we term international vaccine solidarity). We analyse the levels and predictors of international vaccine solidarity. We surveyed a representative sample of German adults (n = 2019) who participated in a two-wave YouGov online survey (w1: Sep 13-21, 2021 and w2: Oct 4-13, 2021). International vaccine solidarity is measured by asking respondents preferences for sharing vaccine supplies internationally versus using that supply as boosters for the domestic population. We examine a set of pre-registered hypotheses. Almost half of the respondents in our sample (48%) prioritize giving doses to citizens in less developed countries. A third of respondents (33%) prefer to use available doses as boosters domestically, and a fifth of respondents (19%) did not report a preference. In line with our hypotheses, respondents higher in cosmopolitanism and empathy, and those who support domestic redistribution exhibit more support for international dose-sharing. Older respondents (who might be more at risk) do not consistently show less support for vaccine solidarity. These results help us to get a better understanding of the way citizens' form preferences about a mechanism that redistributes medical supplies internationally during a global crisis.

Local delivery of tacrolimus using electrospun poly-ϵ-caprolactone nanofibres suppresses the T-cell response to peripheral nerve allografts

Objective.Repair of nerve gap injuries can be achieved through nerve autografting, but this approach is restricted by limited tissue supply and donor site morbidity. The use of living nerve allografts would provide an abundant tissue source, improving outcomes following peripheral nerve injury. Currently this approach is not used due to the requirement for systemic immunosuppression, to prevent donor-derived cells within the transplanted nerve causing an immune response, which is associated with severe adverse effects. The aim of this study was to develop a method for delivering immunosuppression locally, then to test its effectiveness in reducing the immune response to transplanted tissue in a rat model of nerve allograft repair.Approach.A coaxial electrospinning approach was used to produce poly-ϵ-caprolactone fibre sheets loaded with the immunosuppressant tacrolimus. The material was characterised in terms of structure and tacrolimus release, then testedin vivothrough implantation in a rat sciatic nerve allograft model with immunologically mismatched host and donor tissue.Main results.Following successful drug encapsulation, the fibre sheets showed nanofibrous structure and controlled release of tacrolimus over several weeks. Materials containing tacrolimus (and blank material controls) were implanted around the nerve graft at the time of allograft or autograft repair. The fibre sheets were well tolerated by the animals and tacrolimus release resulted in a significant reduction in lymphocyte infiltration at 3 weeks post-transplantation.Significance.These findings demonstrate proof of concept for a novel nanofibrous biomaterial-based targeted drug delivery strategy for immunosuppression in peripheral nerve allografting.

Estimating the size of "anti-vax" and vaccine hesitant populations in the US, UK, and Canada: comparative latent class modeling of vaccine attitudes

Vaccine hesitancy is a significant impediment to global efforts to vaccinate against the SARS-CoV-2 virus at levels that generate herd immunity. In this article, we show the utility of an inductive approach - latent class analysis (LCA) - that allows us to characterize the size and nature of different vaccine attitude groups; and to compare how these groups differ across countries as well as across demographic subgroups within countries. We perform this analysis using original survey data collected in the US, UK, and Canada. We also show that these classes are strongly associated with SARS-CoV-2 vaccination intent and perceptions of the efficacy and safety of the COVID-19 vaccines, suggesting that attitudes about vaccines to fight the novel coronavirus pandemic are well explained by latent vaccine attitudes that precede the pandemic. More specifically, we find four substantive classes of vaccine attitudes: strong supporters, supporters with concerns, vaccine hesitant, and "anti-vax" as well as a fifth measurement error class. The strong "anti-vax" sentiment class is small in all three countries, while the strong supporter class is the largest across all three countries. We observe different distributions of class assignments in different demographic groups - most notably education and political leaning (partisanship and ideology).

Affinity purification of in vivo assembled whirlin-associated protein complexes from the zebrafish retina

Mutations in WHRN lead to Usher syndrome type 2d or to non-syndromic hearing impairment. The WHRN-encoded gene product whirlin directly interacts with the intracellular regions of the other two Usher syndrome type 2-associated proteins, usherin and ADGRV1. In photoreceptor cells, this protein complex constitutes fibrous links between the periciliary membrane and the connecting cilium. However, the molecular mechanism(s) of retinal degeneration due to compromised formation and function of the USH2-associated protein complex remains elusive. To unravel this pathogenic mechanism, we isolated and characterized whirlin-associated protein complexes from zebrafish photoreceptor cells. We generated transgenic zebrafish that express Strep/FLAG-tagged Whrna, a zebrafish ortholog of human whirlin, under the control of a photoreceptor-specific promoter. Affinity purification of Strep/FLAG-tagged Whrna and associated proteins from adult transgenic zebrafish retinas followed by mass spectrometry identified 19 novel candidate associated proteins. Pull down experiments and dedicated yeast two-hybrid assays confirmed the association of Whrna with 7 of the co-purified proteins. Several of the co-purified proteins are part of the synaptic proteome, which indicates a role for whirlin in the photoreceptor synapse. Future studies will elucidate which of the newly identified protein-protein interactions contribute to the development of the retinal phenotype observed in USH2d patients. SIGNIFICANCE: Since protein-protein interactions identified using targeted in vitro studies do not always recapitulate interactions that are functionally relevant in vivo, we established a transgenic zebrafish line that stably expresses a Strep/FLAG-tagged ortholog of human whirlin (SF-Whrna) in photoreceptor cells. Affinity purification of in vivo-assembled SF-Whrna-associated protein complexes from retinal lysates followed by mass spectrometry, identified 19 novel candidate interaction partners, many of which are enriched in the synaptic proteome. Two human orthologs of the identified candidate interaction partners, FRMPD4 and Kir2.3, were validated as direct interaction partners of human whirlin using a yeast two-hybrid assay. The strong connection of whirlin with postsynaptic density proteins was not identified in previous in vitro protein-protein interaction assays, presumably due to the absence of a biologically relevant context. Isolation and identification of in vivo-assembled whirlin-associated protein complexes from the tissue of interest is therefore a powerful methodology to obtain novel insight into tissue specific protein-protein interactions and has the potential to improve significantly our understanding of the function of whirlin and the molecular pathogenesis underlying Usher syndrome type 2.

Minimal effects from injunctive norm and contentiousness treatments on COVID-19 vaccine intentions: evidence from 3 countries

Does information about how other people feel about COVID-19 vaccination affect immunization intentions? We conducted preregistered survey experiments in Great Britain (5,456 respondents across 3 survey waves from September 2020 to February 2021), Canada (1,315 respondents in February 2021), and the state of New Hampshire in the United States (1,315 respondents in January 2021). The experiments examine the effects of providing accurate public opinion information to people about either public support for COVID-19 vaccination (an injunctive norm) or public beliefs that the issue is contentious. Across all 3 countries, exposure to this information had minimal effects on vaccination intentions even among people who previously held inaccurate beliefs about support for COVID-19 vaccination or its perceived contentiousness. These results suggest that providing information on public opinion about COVID vaccination has limited additional effect on people's behavioral intentions when public discussion of vaccine uptake and intentions is highly salient.

A combined experimental and computational framework to evaluate the behavior of therapeutic cells for peripheral nerve regeneration

Recent studies have explored the potential of tissue‐mimetic scaffolds in encouraging nerve regeneration. One of the major determinants of the regenerative success of cellular nerve repair constructs (NRCs) is the local microenvironment, particularly native low oxygen conditions which can affect implanted cell survival and functional performance. In vivo, cells reside in a range of environmental conditions due to the spatial gradients of nutrient concentrations that are established. Here we evaluate in vitro the differences in cellular behavior that such conditions induce, including key biological features such as oxygen metabolism, glucose consumption, cell death, and vascular endothelial growth factor secretion. Experimental measurements are used to devise and parameterize a mathematical model that describes the behavior of the cells. The proposed model effectively describes the interactions between cells and their microenvironment and could in the future be extended, allowing researchers to compare the behavior of different therapeutic cells. Such a combinatorial approach could be used to accelerate the clinical translation of NRCs by identifying which critical design features should be optimized when fabricating engineered nerve repair conduits.

The ephemeral effects of fact-checks on COVID-19 misperceptions in the United States, Great Britain and Canada

Widespread misperceptions about COVID-19 and the novel coronavirus threaten to exacerbate the severity of the pandemic. We conducted preregistered survey experiments in the United States, Great Britain and Canada examining the effectiveness of fact-checks that seek to correct these false or unsupported beliefs. Across three countries with differing levels of political conflict over the pandemic response, we demonstrate that fact-checks reduce targeted misperceptions, especially among the groups who are most vulnerable to these claims, and have minimal spillover effects on the accuracy of related beliefs. However, these reductions in COVID-19 misperception beliefs do not persist over time in panel data even after repeated exposure. These results suggest that fact-checks can successfully change the COVID-19 beliefs of the people who would benefit from them most but that their effects are ephemeral.

Controlled local release of PPARγ agonists from biomaterials to treat peripheral nerve injury

OBJECTIVE

Poor clinical outcomes following peripheral nerve injury (PNI) are partly attributable to the limited rate of neuronal regeneration. Despite numerous potential drug candidates demonstrating positive effects on nerve regeneration rate in preclinical models, no drugs are routinely used to improve restoration of function in clinical practice. A key challenge associated with clinical adoption of drug treatments in nerve injured patients is the requirement for sustained administration of doses associated with undesirable systemic sideeffects. Local controlled-release drug delivery systems could potentially address this challenge, particularly through the use of biomaterials that can be implanted at the repair site during the microsurgical repair procedure.

APPROACH

In order to test this concept, this study used various biomaterials to deliver ibuprofen sodium or sulindac sulfide locally in a controlled manner in a rat sciatic nerve injury model. Following characterisation of release parameters in vitro, ethylene vinyl acetate tubes or polylactic-co-glycolic acid wraps, loaded with ibuprofen sodium or sulindac sulfide, were placed around directly-repaired nerve transection or nerve crush injuries in rats.

MAIN RESULTS

Ibuprofen sodium, but not sulindac sulfide caused an increase in neurites in distal nerve segments and improvements in functional recovery in comparison to controls with no drug treatment.

SIGNIFICANCE

This study showed for the first time that local delivery of ibuprofen sodium using biomaterials improves neurite growth and functional recovery following PNI and provides the basis for future development of drug-loaded biomaterials suitable for clinical translation.

Combining in silico and in vitro models to inform cell seeding strategies in tissue engineering

The seeding density of therapeutic cells in engineered tissue impacts both cell survival and vascularization. Excessively high seeded cell densities can result in increased death and thus waste of valuable cells, whereas lower seeded cell densities may not provide sufficient support for the tissue in vivo, reducing efficacy. Additionally, the production of growth factors by therapeutic cells in low oxygen environments offers a way of generating growth factor gradients, which are important for vascularization, but hypoxia can also induce unwanted levels of cell death. This is a complex problem that lends itself to a combination of computational modelling and experimentation. Here, we present a spatio-temporal mathematical model parametrized using in vitro data capable of simulating the interactions between a therapeutic cell population, oxygen concentrations and vascular endothelial growth factor (VEGF) concentrations in engineered tissues. Simulations of collagen nerve repair constructs suggest that specific seeded cell densities and non-uniform spatial distributions of seeded cells could enhance cell survival and the generation of VEGF gradients. These predictions can now be tested using targeted experiments.

Neural cell responses to wear debris from metal-on-metal total disc replacements

PURPOSE

Total disc replacements, comprising all-metal articulations, are compromised by wear and particle production. Metallic wear debris and ions trigger a range of biological responses including inflammation, genotoxicity, cytotoxicity, hypersensitivity and pseudotumour formation, therefore we hypothesise that, due to proximity to the spinal cord, glial cells may be adversely affected.

METHODS

Clinically relevant cobalt chrome (CoCr) and stainless steel (SS) wear particles were generated using a six-station pin-on-plate wear simulator. The effects of metallic particles (0.5-50 μm³ debris per cell) and metal ions on glial cell viability, cellular activity (glial fibrillary acidic protein (GFAP) expression) and DNA integrity were investigated in 2D and 3D culture using live/dead, immunocytochemistry and a comet assay, respectively.

RESULTS

CoCr wear particles and ions caused significant reductions in glial cell viability in both 2D and 3D culture systems. Stainless steel particles did not affect glial cell viability or astrocyte activation. In contrast, ions released from SS caused significant reductions in glial cell viability, an effect that was especially noticeable when astrocytes were cultured in isolation without microglia. DNA damage was observed in both cell types and with both biomaterials tested. CoCr wear particles had a dose-dependent effect on astrocyte activation, measured through expression of GFAP.

CONCLUSIONS

The results from this study suggest that microglia influence the effects that metal particles have on astrocytes, that SS ions and particles play a role in the adverse effects observed and that SS is a less toxic biomaterial than CoCr alloy for use in spinal devices. These slides can be retrieved under Electronic Supplementary Material.

Quantifying regeneration in patients following peripheral nerve injury

Healthy nerve function provides humans with the control of movement; sensation (such as pain, touch and temperature) and the quality of skin, hair and nails. Injury to this complex system creates a deficit in function, which is slow to recover, and rarely, if ever, returns to what patients consider to be normal. Despite promising results in pre-clinical animal experimentation effective translation is challenged by a current inability to quantify nerve regeneration in human subjects and relate this to measurable and responsible clinical outcomes. In animal models, muscle and nerve tissue samples can be harvested following experimental intervention. This allows direct quantification of muscle mass and quality and quantity of regeneration of axons; such an approach is not applicable in human medicine as it would ensure a significant functional deficit. Nevertheless a greater understanding of this process would allow the relationship that exists between neural and neuromuscular regeneration and functional outcome to be more clearly understood. This article presents a combined commentary of current practice from a specialist clinical unit and research team with regard to laboratory and clinical quantification of nerve regeneration. We highlight how electrophysiological diagnostic methods (which are used with significant recognised limitations in the assessment of clinical medicine) can potentially be used with more validity to interpret and assess the processes of neural regeneration in the clinical context, thus throwing light on the factors at play in translating lab advances into the clinic.

P25 Hydrogel systems to enhance the delivery of cell therapy for traumatic spinal cord injury

Objectives

Cell therapies are an emerging therapeutic approach for spinal cord injury. We assessed the survival and phenotype of olfactory ensheathing cells (OECs) in hydrogel delivery systems suitable for clinical use.

Design

Laboratory study.

Methods

Cell survival in different formulations of collagen and fibrin hydrogels was assessed using Syto 9 and propidium iodide. The proportion of cells staining positive for a key repair marker (p75NTR) was also quantified using immunocytochemistry and fluorescence microscopy.

Results

There were significant differences in OEC survival between the various collagen and fibrin hydrogel formulations tested (p<0.001 one-way ANOVA, n=17). 10% v/v fibrin conferred the best cell survival with 85% of OECs remaining alive. Incorporating OECs into collagen hydrogels promoted the highest proportion of p75NTR immunopositive cells (78%) and this was significantly higher than both fibrin hydrogels and traditional monolayer culture (53% and 20%, respectively, p<0.0001 one-way ANOVA, n=24).

Conclusions

Collagen and fibrin hydrogels both have the potential to enhance the delivery, survival and retention of transplanted OECs for spinal cord repair. Both materials are clinically scalable, promote favourable OEC survival and have the potential to increase the proportion of cells expressing a key repair marker (p75NTR). Optimised hydrogel delivery systems may provide a valuable approach to improve the delivery of OECs for spinal cord repair in the future.

An allogeneic 'off the shelf' therapeutic strategy for peripheral nerve tissue engineering using clinical grade human neural stem cells

Artificial tissues constructed from therapeutic cells offer a promising approach for improving the treatment of severe peripheral nerve injuries. In this study the effectiveness of using CTX0E03, a conditionally immortalised human neural stem cell line, as a source of allogeneic cells for constructing living artificial nerve repair tissue was tested. CTX0E03 cells were differentiated then combined with collagen to form engineered neural tissue (EngNT-CTX), stable aligned sheets of cellular hydrogel. EngNT-CTX sheets were delivered within collagen tubes to repair a 12 mm sciatic nerve injury model in athymic nude rats. Autologous nerve grafts (autografts) and empty tubes were used for comparison. After 8 weeks functional repair was assessed using electrophysiology. Further, detailed histological and electron microscopic analysis of the repaired nerves was performed. Results indicated that EngNT-CTX supported growth of neurites and vasculature through the injury site and facilitated reinnervation of the target muscle. These findings indicate for the first time that a clinically validated allogeneic neural stem cell line can be used to construct EngNT. This provides a potential 'off the shelf' tissue engineering solution for the treatment of nerve injury, overcoming the limitations associated with nerve autografts or the reliance on autologous cells for populating repair constructs.

Zebrafish models of human eye and inner ear diseases

Eye and inner ear diseases are the most common sensory impairments that greatly impact quality of life. Zebrafish have been intensively employed to understand the fundamental mechanisms underlying eye and inner ear development. The zebrafish visual and vestibulo-acoustic systems are very similar to these in humans, and although not yet mature, they are functional by 5days post-fertilization (dpf). In this chapter, we show how the zebrafish has significantly contributed to the field of biomedical research and how researchers, by establishing disease models and meticulously characterizing their phenotypes, have taken the first steps toward therapies. We review here models for (1) eye diseases, (2) ear diseases, and (3) syndromes affecting eye and/or ear. The use of new genome editing technologies and high-throughput screening systems should increase considerably the speed at which knowledge from zebrafish disease models is acquired, opening avenues for better diagnostics, treatments, and therapies.

Odours stimulate neuronal activity in the dorsolateral area of the hippocampal formation during path integration

The dorsolateral area of the hippocampal formation of birds is commonly assumed to play a central role in processing information needed for geographical positioning and homing. Previous work has interpreted odour-induced activity in this region as evidence for an 'olfactory map'. Here, we show, using c-Fos expression as a marker, that neuronal activation in the dorsolateral area of the hippocampal formation of pigeons is primarily a response to odour novelty, not to the spatial distribution of odour sources that would be necessary for an olfactory map. Pigeons exposed to odours had significantly more neurons activated in this area of the brain than pigeons exposed to filtered air with odours removed. This increased activity was observed only in response to unfamiliar odours. No change in activity was observed when pigeons were exposed to home odours. These findings are consistent with non-home odours activating non-olfactory components of the pigeon's navigation system. The pattern of neuronal activation in the triangular and dorsomedial areas of the hippocampal formation was, by contrast, consistent with the possibility that odours play a role in providing spatial information.

Separation orthogonality in temperature-programmed comprehensive two-dimensional gas chromatography

In a comprehensive two-dimensional gas chromatograph, a thermal modulator serially couples two columns containing dissimilar stationary phases. The secondary column generates a series of high-speed secondary chromatograms from the sample stream formed by the chromatogram eluting from the primary column. This series of secondary chromatograms forms a two-dimensional gas chromatogram with peaks dispersed over a retention plane rather than along a line. The method is comprehensive because the entire primary column chromatogram is transmitted through the secondary column with fidelity. One might expect that a two-dimensional separation in which both dimensions are basically the same technique, gas chromatography, would be inefficient because the two dimensions would behave similarly, generating peaks whose retentions correlate across dimensions. Applying a temperature program to the two columns, however, can tune the separation to eliminate this inefficiency. The temperature program reduces the retentive power of the secondary column as a function of progress of the primary chromatogram such that the retention mechanism of the primary column is eliminated from the second dimension. Retention of a substance in the second dimension is then determined by the difference in its interaction with the two stationary phases. Retention times in the second dimension then fall within a fixed range, and the whole retention plane is accessible. In a properly tuned comprehensive two-dimensional chromatogram, retention times in the two dimensions are independent of each other, and the two-dimensional chromatogram is orthogonal. Orthogonality is important for two reasons. First, an orthogonal separation efficiently uses the separation space and so has either greater speed or peak capacity than nonorthogonal separations. Second, retention in the two dimensions of an orthogonal chromatogram is determined by two different and independent mechanisms and so provides two independent measures of molecular properties.

A drug delivery system for the treatment of peripheral nervous system injuries

Recent results in biomedical engineering and materials science and technology have brought about the development of novel bioactive materials by which the repair of peripheral nervous system injuries can be improved. The formation of scarring tissue, which represents a physical barrier to axon elongation, and the not oriented outgrowth of neurites are the two major obstacles for a complete recovery of physiological nerve function. This study mainly focuses on the analysis of biocompatible constructs for the controlled release of anti-scarring antibodies by means of fluorescence spectroscopy techniques.

Characterization of non-neuronal elements within fibronectin mats implanted into the damaged adult rat spinal cord

Previous studies have shown that mats made from fibronectin (FN) integrate well into spinal cord lesion sites and support extensive axonal growth. Using immunohistochemistry, we have investigated the non-neuronal factors that contribute to these properties. Extensive vascularization was observed in FN mats by 1 week along with heavy macrophage infiltration by 3 days post-implantation. By 1 week post-implantation, laminin tubules had formed and were associated with axons and p75 immunoreactive Schwann cells. By 4 weeks post-implantation, most axons were associated with Schwann cell derived myelin. Few oligodendrocytes were present within the mat, even with an increase in the number of oligodendrocyte precursors around the implant site by 7 days post-implantation. Astrocyte proliferation also occurred in the intact tissue, with a prominent glial scar forming around the implant within 4 weeks. However, by 2 months post-implantation astrocytes were present in the FN implant site and were intermingled with the axons. Axonal ingrowth and integration of the FN mats is probably due to the ability of FN mats to support and organize infiltration of Schwann cells and deposition of laminin. At later time points, myelinated axons remain in the implant site, even after other elements (e.g. macrophages and laminin) have disappeared. Both of these properties are likely to be important in the design of biomaterial bridges for CNS regeneration.

Tennessee Trauma Care System Plan, part III

Tennessee implemented a statewide trauma care system in 1988. This system serves the state of Tennessee and supports eight neighboring states. The demographics and geography of Tennessee have ensured that nearly all residents have rapid access to the trauma care system. However, since 1988, many changes have occurred in healthcare in general, and trauma care in particular, that point out problems and issues with the Tennessee trauma care system. Therefore, the Tennessee Trauma Care Advisory Council has developed this Trauma Care System Plan to look at needs and opportunities for the future of trauma care in Tennessee. This plan will be presented in four segments: History, Administrative Components, Operational Components, and Clinical Components.

Tennessee trauma care system plan, Part II

Tennessee implemented a statewide trauma care system in 1988. This system serves the state of Tennessee and supports eight neighboring states. The demographics and geography of Tennessee have ensured that nearly all residents have rapid access to the trauma care system. However, since 1988, many changes have occurred in healthcare in general, and trauma care in particular, that point out problems and issues with the Tennessee trauma care system. Therefore, the Tennessee Trauma Care Advisory Council has developed this Trauma Care System Plan to look at needs and opportunities for the future of trauma care in Tennessee. This plan will be presented in four segments: History, Administrative Components, Operational Components, and Clinical Components.

Investigating the mechanical shear-plane between core and sheath elements of peripheral nerves

The mechanical architecture of rat sciatic nerve has been described as a central core surrounded by a sheath, although the way in which these structures contribute to the overall mechanical properties of the nerve is unknown. We have studied the retraction responses of the core and sheath following transection, together with their tensile properties and the interface between them. Nerves were harvested and maintained at their in situ tension and then either transected entirely, through the sheath only, or through an exposed section of the core. The retraction of each component was measured within 5 min and again after 45 min. Post mortem loss of retraction was tested 0 min or 60 min after excision. For fresh nerves, immediate retraction was 12.68% (whole nerve), 5.35% (sheath) and 4% (core), with a total retraction of 15%, 7.21% and 5.26% respectively. For stored nerves, immediate retraction was 5.33% (whole nerve) and 5.87% (sheath), with an extension of 0.78% for core, and a total retraction of 6.71% and 7.87% and an extension of 1.74%, respectively. Tensile extension and pullout force profiles were obtained for the sheath, the core and the interface between them. These showed a consistent hierarchy of break strengths that would, under increasing load, result in failure of the interface, then the core and finally the sheath. These data reflect the contributions of material tension and fluid swelling pressure to total retraction, and the involvement of an energy-dependent process that runs down rapidly post mortem. This study increases our understanding of the composite nature of peripheral nerve tissue architecture and quantifies the material properties of the distinct elements that contribute to overall mechanical function.

Tennessee trauma care system plan, Part 1

Tennessee implemented a statewide trauma care system in 1988. This system serves the state of Tennessee and supports eight neighboring states. The demographics and geography of Tennessee have ensured that nearly all residents have rapid access to the trauma care system. However, since 1988, many changes have occurred in healthcare in general, and trauma care in particular, that point out problems and issues with the Tennessee trauma care system. Therefore, the Tennessee Trauma Care Advisory Council has developed this Trauma Care System Plan to look at needs and opportunities for the future of trauma care in Tennessee. This plan will be presented in four segments: History, Administrative Components, Operational Components, and Clinical Components.

Peripheral nerves in the rat exhibit localized heterogeneity of tensile properties during limb movement

Peripheral nerves in the limbs stretch to accommodate changes in length during normal movement. The aim of this study was to determine how stretch is distributed along the nerve relative to local variations in mechanical properties. Deformation (strain) in joint and non-joint regions of rat median and sciatic nerves was measured in situ during limb movement using optical image analysis. In each nerve the strain was significantly greater in the joint rather than the non-joint regions (2-fold in the median nerve, 5- to 10-fold in the sciatic). In addition, this difference in strain was conserved in the median nerve ex vivo, demonstrating an in-built longitudinal heterogeneity of mechanical properties. Tensile testing of isolated samples of joint and non-joint regions of both nerves showed that joint regions were less stiff (more compliant) than their non-joint counterparts with joint: non-joint stiffness ratios of 0.5 +/- 0.07 in the median nerve, and 0.8 +/- 0.02 in the sciatic. However, no structural differences identified at the light microscope level in fascicular/non-fascicular tissue architecture between these two nerve regions could explain the observed tensile heterogeneity. This identification of localized functional heterogeneity in tensile properties is particularly important in understanding normal dynamic nerve physiology, provides clues to why peripheral nerve repair outcomes are variable, and suggests potential novel therapeutic targets.

Optimal mechanisms for finding and selecting mates: how threespine stickleback ( Gasterosteus aculeatus ) should encode male throat colors

Male threespine stickleback ( Gasterosteus aculeatus) use nuptial colors to attract mates and intimidate rivals. We quantified stickleback color and environmental lighting using methods independent of human perception to evaluate the information transmitted by male signals in a habitat where these signals are displayed. We also developed models of chromatic processing based on four cone photopigments (peak absorptions at 360, 445, 530, and 605 nm) characterized microspectrophotometrically in G. aculeatus and three other stickleback species. We show that a simple opponent mechanism receiving equally weighted inputs from cones with peak absorptions at 445 nm and 605 nm efficiently encodes variation in male throat colors. An orthogonal opponent mechanism-the difference between outputs of 530-nm cones and mean of outputs of 445- and 605-nm cones-produces a neural signal that could be used for species recognition and would be largely insensitive to variation in male throat color. We also show that threespine stickleback throats/photopigments are optimized for this coding scheme. These and other findings lead to testable hypotheses about the spectral processing mechanisms present in the threespine stickleback visual systems and the evolutionary interactions that have shaped this signal/receiver system.

The effects of treatment with antibodies to transforming growth factor β1 and β2 following spinal cord damage in the adult rat

We recently showed axonal ingrowth into fibronectin (FN) mats implanted into the spinal cord. However, little axonal growth was found from FN mats into intact spinal cord. Previous research has shown that this is due in part to astrocytosis around an area of CNS damage. Antibodies to transforming growth factor beta (TGFbeta) can diminish this astrocytosis. TGFbeta also has effects on macrophages and Schwann cells, both of which infiltrate the spinal cord following damage. We examined the axonal, Schwann cell, and macrophage infiltration into FN mats as well as the level of astrocytosis and chondroitin sulfate proteoglycan NG2 around FN implants incubated in TGFbeta antibodies and implanted into a lesion cavity in the spinal cord. We also examined the effects of applying TGFbeta antibodies to a spinal cord hemisection site. Anti-TGFbeta1 within FN mats resulted in extensive cavitation, with the area of damage being larger than the original lesion. Cavitation was also seen following application of anti-TGFbeta1 to a spinal cord hemisection site. No cavitation was seen following saline, non-immune IgG or anti-TGFbeta2 treatment. However, anti-TGFbeta2 treatment did result in diminished axonal growth and Schwann cell and macrophage infiltration. Around the implant site, anti-TGFbeta2 treatment resulted in a reduction in the level of astrocytosis but had not effect on levels of NG2. Similar effects were seen following anti-TGFbeta2 application to spinal cord hemisection sites. The results suggest that anti-TGFbeta1 exacerbates secondary damage by preventing the anti-inflammatory effect of endogenous TGFbeta1. Anti-TGFbeta2 did not enhance axonal regeneration in this model but did slightly reduce astrocytosis.

zyg-8, a gene required for spindle positioning in C. elegans, encodes a doublecortin-related kinase that promotes microtubule assembly

Proper spindle positioning is essential for spatial control of cell division. Here, we show that zyg-8 plays a key role in spindle positioning during asymmetric division of one-cell stage C. elegans embryos by promoting microtubule assembly during anaphase. ZYG-8 harbors a kinase domain and a domain related to Doublecortin, a microtubule-associated protein (MAP) affected in patients with neuronal migration disorders. Sequencing of zyg-8 mutant alleles demonstrates that both domains are essential for function. ZYG-8 binds to microtubules in vitro, colocalizes with microtubules in vivo, and promotes stabilization of microtubules to drug or cold depolymerization in COS-7 cells. Our findings demonstrate that ZYG-8 is a MAP crucial for proper spindle positioning in C. elegans, and indicate that the function of the Doublecortin domain in modulating microtubule dynamics is conserved across metazoan evolution.

The role of extraocular photoreceptors in newt magnetic compass orientation: parallels between light-dependent magnetoreception and polarized light detection in vertebrates

Theoretical models implicating specialized photoreceptors in the detection of the geomagnetic field have been the impetus for studying the effects of light on magnetic compass orientation. Magnetic orientation in flies, amphibians and birds has been found to be influenced by light, and in all these groups a shift of approximately 90° in the direction of magnetic compass orientation has been observed under certain wavelengths and/or intensities of light. In the eastern red-spotted newt Notophthalmus viridescens, wavelength-dependent effects of light on magnetic compass orientation appear to result from an antagonistic interaction between short-wavelength (≤450nm) and long-wavelength (≥500nm) photoreception mechanisms. We have demonstrated that at least the short-wavelength input to the newt’s magnetic compass is mediated by extraocular photoreceptors located in or near the pineal organ, and here we present new findings that indicate that the putative long-wavelength mechanism is also associated with pineal photoreceptors. Interestingly, the amphibian pineal organ mediates orientation to both the e-vector of plane-polarized light and the magnetic field. Although the wavelength-dependence of the polarized light orientation in amphibians has not been studied, polarization sensitivity in fishes appears to be mediated by two antagonistic photoreception mechanisms that have similar spectral characteristics to those of the newts’ magnetic compass response. These parallels, along with similarities in the types of receptors that are expected to be involved in light-dependent magnetoreception and polarized light detection, suggest that similar photoreception mechanisms may mediate the light-dependent magnetic and polarized light compasses.

DNA replication defects delay cell division and disrupt cell polarity in early Caenorhabditis elegans embryos

In early Caenorhabditis elegans embryos, asymmetric cell divisions produce descendants with asynchronous cell cycle times. To investigate the relationship between cell cycle regulation and pattern formation, we have identified a collection of embryonic-lethal mutants in which cell divisions are delayed and cell fate patterns are abnormal. In div (for division delayed) mutant embryos, embryonic cell divisions are delayed but remain asynchronous. Some div mutants produce well-differentiated cell types, but they frequently lack the endodermal and mesodermal cell fates normally specified by a transcriptional activator called SKN-1. We show that mislocalization of PIE-1, a negative regulator of SKN-1, prevents the specification of endoderm and mesoderm in div-1 mutant embryos. In addition to defects in the normally asymmetric distribution of PIE-1, div mutants also exhibit other losses of asymmetry during early embryonic cleavages. The daughters of normally asymmetric divisions are nearly equal in size, and cytoplasmic P-granules are not properly localized to germline precursors in div mutant embryos. Thus the proper timing of cell division appears to be important for multiple aspects of asymmetric cell division. One div gene, div-1, encodes the B subunit of the DNA polymerase alpha-primase complex. Reducing the function of other DNA replication genes also results in a delayed division phenotype and embryonic lethality. Thus the other div genes we have identified are likely to encode additional components of the DNA replication machinery in C. elegans.

Handshaking, gender, personality, and first impressions

Although people's handshakes are thought to reflect their personality and influence our first impressions of them, these relations have seldom been formally investigated. One hundred twelve participants had their hand shaken twice by 4 trained coders (2 men and 2 women) and completed 4 personality measures. The participants' handshakes were stable and consistent across time and coders. There were also gender differences on most of the handshaking characteristics. A firm handshake was related positively to extraversion and emotional expressiveness and negatively to shyness and neuroticism; it was also positively related to openness to experience, but only for women. Finally, handshake characteristics were related to the impressions of the participants formed by the coders. These results demonstrate that personality traits, assessed through self-report, can predict specific behaviors assessed by trained observers. The pattern of relations among openness, gender, handshaking, and first impressions suggests that a firm handshake may be an effective form of self-promotion for women.

Handshaking, gender, personality, and first impressions

Although people's handshakes are thought to reflect their personality and influence our first impressions of them, these relations have seldom been formally investigated. One hundred twelve participants had their hand shaken twice by 4 trained coders (2 men and 2 women) and completed 4 personality measures. The participants' handshakes were stable and consistent across time and coders. There were also gender differences on most of the handshaking characteristics. A firm handshake was related positively to extraversion and emotional expressiveness and negatively to shyness and neuroticism; it was also positively related to openness to experience, but only for women. Finally, handshake characteristics were related to the impressions of the participants formed by the coders. These results demonstrate that personality traits, assessed through self-report, can predict specific behaviors assessed by trained observers. The pattern of relations among openness, gender, handshaking, and first impressions suggests that a firm handshake may be an effective form of self-promotion for women.

Proteasome inhibitor PS519 reduces infarction and attenuates leukocyte infiltration in a rat model of focal cerebral ischemia

BACKGROUND AND PURPOSE

Reperfusion brain injury after cerebral ischemia is associated with a developing inflammatory response at the site of infarction. Proteasome inhibitors block nuclear factor-kappaB activation and provide anti-inflammatory effects in several animal models of peripheral inflammation. We tested the novel proteasome inhibitor PS519 in a rat model of transient focal ischemia to establish its pharmacodynamics as a neuroprotection treatment and related effects on leukocyte infiltration.

METHODS

Rats were subjected to 2 hours of focal cerebral ischemia by means of the filament method of middle cerebral artery occlusion (MCAo). After either 22 or 70 hours of reperfusion, infarct size was measured and neurological function, electroencephalographic (EEG) activity, and/or neutrophil and macrophage infiltration was quantified. PS519 was administered in a single intravenous bolus at 2 hours after MCAo. In addition, the therapeutic window for PS519 was estimated by delaying treatment for 4 or 6 hours after MCAo.

RESULTS

Dose-response analysis of infarct volume at 24 hours revealed that PS519 neuroprotection approached 60%, and clinical evaluations showed significant improvements in neurological function and EEG activity. Neutrophil infiltration at 24 hours was also significantly decreased in cortical and striatal infarcted tissue of PS519-treated rats. Delaying the PS519 treatment up to 4 hours continued to result in significant neuroprotection. In the 72-hour injury model, infarction was reduced 40% by PS519, and significant improvements in neurological function and EEG recovery were again measured. Considerable reductions in both neutrophil and macrophage infiltration were evident.

CONCLUSIONS

PS519 mitigates infarction and improves neurological recovery in brain-injured rats, an effect in part caused by a reduction in the leukocyte inflammatory response.

Neuroprotective efficacy and therapeutic window of the high-affinity N-methyl-D-aspartate antagonist conantokin-G: in vitro (primary cerebellar neurons) and in vivo (rat model of transient focal brain ischemia) studies

Conantokin-G (Con-G), a 17-amino-acid peptide derived from marine snails and a potent N-methyl-D-aspartate (NMDA) antagonist, was evaluated for its neuroprotective properties in vitro and in vivo. In primary cerebellar neurons, Con-G was shown to decrease excitotoxic calcium responses to NMDA and to exhibit differential neuroprotection potencies against hypoxia/hypoglycemia-, NMDA-, glutamate-, or veratridine-induced injury. Using the intraluminal filament method of middle cerebral artery occlusion as an in vivo rat model of transient focal brain ischemia, the neuroprotective dose-response effect of Con-G administration beginning 30 min postocclusion was evaluated after 2 h of ischemia and 22 h of reperfusion. In the core region of injury, an 89% reduction in brain infarction was measured with significant neurological and electroencephalographic recovery at the maximal dose tested (2 nmol), although mild sedation was noted. Lower doses of Con-G (0.001-0.5 nmol) were significantly neuroprotective without causing sedation. Postinjury time course experiments demonstrated a therapeutic window out to at least 4 to 8 h from the start of the injury, providing a 47% reduction in core injury. The neuroprotective effect of Con-G (0. 5 nmol) was also evaluated after 72 h of injury, where a 54% reduction in core brain infarction was measured. Critically, in both recovery models (i.e., 24 and 72 h), the reduction in brain infarction was associated with significant improvements in neurological and electroencephalographic recovery. These data provide evidence for the potent and highly efficacious effect of Con-G as a neuroprotective agent, with an excellent therapeutic window for the potential intervention against ischemic/excitotoxic brain injury.

Ferromagnetic material in the eastern red-spotted newt notophthalmus viridescens

Behavioral results obtained from the eastern red-spotted newt (Notophthalmus viridescens) led to the suggestion of a hybrid homing system involving inputs from both a light-dependent and a non-light-dependent mechanism. To evaluate the possible role of a receptor based on biogenic magnetite in this animal, we performed magnetometry experiments on a set of newts previously used in behavioral assays. The natural remanent magnetization (NRM) carried by these newts was strong enough to be measured easily using a direct-current-biased superconducting quantum interference device functioning as a moment magnetometer. Isothermal remanent magnetizations were two orders of magnitude higher than the NRM, suggesting that ferromagnetic material consistent with magnetite is present in the body of the newt. The NRM has no preferential orientation among the animals when analyzed relative to their body axis, and the demagnetization data show that, overall, the magnetic material grains are not aligned parallel to each other within each newt. Although the precise localization of the particles was not possible, the data indicate that magnetite is not clustered in a limited area. A quantity of single-domain magnetic material is present which would be adequate for use in either a magnetic intensity or direction receptor. Our data, when combined with the functional properties of homing, suggest a link between this behavioral response and the presence of ferromagnetic material, raising the possibility that magnetite is involved at least in the map component of homing of the eastern red-spotted newt.

Comprehensive two-dimensional gas chromatography: a hyphenated method with strong coupling between the two dimensions

Comprehensive two-dimensional gas chromatography (GC x GC) provides a true orthogonal separation system. It is explained and demonstrated that it generates a peak capacity that is approximately equal to the product of the peak capacities of the two individual separation systems. The resulting peaks are ordered in a two-dimensional plane in bands of compounds with the same characteristics. Quantitation of the separated (groups of) components is fundamentally not different from one-dimensional gas chromatography, but the sensitivity is far better and true baseline is always available. The two co-ordinates of each peak in the plane make the identification more reliable. Instrumental considerations of GC x GC are discussed. The three designs of contemporary GC x GC systems are presented and compared. Although the technique is still very young, a number of applications on complex samples as petroleum and environmental samples have already been reported. Finally, the future perspectives of GC x GC are discussed.

The case for light-dependent magnetic orientation in animals

Light-dependent models of magnetoreception have been proposed which involve an interaction between the magnetic field and either magnetite particles located within a photoreceptor or excited states of photopigment molecules. Consistent with a photoreceptor-based magnetic compass mechanism, magnetic orientation responses in salamanders, flies and birds have been shown to be affected by the wavelength of light. In birds and flies, it is unclear whether the effects of light on magnetic orientation are due to a direct effect on a magnetoreception system or to a nonspecific (e.g. motivational) effect of light on orientation behavior. Evidence from shoreward-orienting salamanders, however, demonstrates that salamanders perceive a 90 degrees counterclockwise shift in the direction of the magnetic field under long-wavelength (&gt;=500 nm) light. A simple physiological model based on the antagonistic interaction between two magnetically sensitive spectral mechanisms suggests one possible way in which the wavelength-dependent effects of light on the salamander's magnetic compass response might arise. Assuming that the wavelength-dependent characteristics of the avian magnetic response can be attributed to an underlying magnetoreception system, we discuss several hypotheses attempting to resolve the differences observed in the wavelength-dependent effects of light on magnetic orientation in birds and salamanders. By considering the evidence in the context of photoreceptor- and non-photoreceptor-based mechanisms for magnetoreception, we hope to encourage future studies designed to distinguish between alternative hypotheses concerning the influence of light on magnetoreception.

Life cycle of Ixodes minor (Acari: Ixodidae) in the laboratory

Details of the laboratory life cycle of 3 generations of Ixodes minor Neumann were recorded. Larvae and nymphs were fed on white laboratory mice and adults were fed on woodrats. Nymphs fed for 4 d and larvae for an average of 4 d; approximately 10 to 11 d were required for females to engorge. After feeding, females laid approximately 1,600 eggs that required an average of 39.7 d to hatch. Eggs were maintained at 97.5% RH and approximately 25 degrees C as were all stages of the ticks when not feeding. The life cycle in the laboratory required approximately 180 d; however, in nature it probably takes longer. I. minor has been recorded from several rodent and bird species known to be infected with Borrelia burgdorferi (Johnson, Schmid, Hyde, Steigerwalt & Brenner). This study provides data on the life cycle of a potential enzootic tick vector of this spirochete.

Release of endogenous glutamate and gamma-aminobutyric acid from rat striatal tissue slices measured by an improved method of high performance liquid chromatography with electrochemical detection

The release of endogenous glutamate and gamma-aminobutyric acid (GABA) from rat brain tissue slices was studied using a tissue slice assay in which detectable amounts of the amino acids were released from 1-2 mg of tissue. An improved method of high performance liquid chromatography (HPLC) with electrochemical detection was employed to measure both glutamate and GABA after derivatization with o-phthalaldehyde and sulphite in a single isocratic HPLC analysis. The non-endogenous amino acid, homoglutamine, was used as an internal standard in verifying the consistent derivatization of amino acids and in quantifying amounts of glutamate and GABA released from the caudate-putamen tissue. The derivatized amino acids (1-30 pmol) were detected as chromatographic peaks eluting at baseline level and free of significant interfering co-eluates in a 25-30 min analysis time.

Release of endogenous glutamate and gamma-aminobutyric acid from rat striatal tissue slices measured by an improved method of high performance liquid chromatography with electrochemical detection

The release of endogenous glutamate and gamma-aminobutyric acid (GABA) from rat brain tissue slices was studied using a tissue slice assay in which detectable amounts of the amino acids were released from 1-2 mg of tissue. An improved method of high performance liquid chromatography (HPLC) with electrochemical detection was employed to measure both glutamate and GABA after derivatization with o-phthalaldehyde and sulfide in a single isocratic HPLC analysis. The non-endogenous amino acid, homoglutamine, was used as an internal standard in verifying the consistent derivatization of amino acids and in quantifying amounts of glutamate and GABA released from the caudate-putamen tissue. The derivatized amino acids (1-30 pmol) were detected as chromatographic peaks eluting at baseline level and free of significant interfering co-eluates in a 25-30 min analysis time.

Umbilical artery catheter blood sampling alters cerebral blood flow velocity in preterm infants

OBJECTIVE

Changes in cerebral blood flow velocity (CBFV) have been associated with occurrence of intraventricular hemorrhage in preterm infants. Blood sampling from umbilical artery catheters (UACs) may cause changes in CBFV. Two UAC positions are generally used, high (T6 to T10) and low (L3 to L5). We hypothesized that CBFV changes would occur during UAC sampling and that CBFV changes would be greater in the high than the low position.

STUDY DESIGN

We measured CBFV in the anterior cerebral artery in 30 very low birth weight infants before, during, and after aspiration and replacement of blood from UACs in both high and low positions. CBFV was calculated as the area under the velocity curve (AUVC) and the pulsatility index. Data were analyzed by paired t tests and repeated-measures multivariate analysis of variance.

RESULTS

Blood sampling from UACs produced significant changes from baseline in CBFV during aspiration (-19%) and replacement (+9%) of blood from high UACs and during aspiration (-8%) of blood from low-positioned UACs. Overall, there was a 35% difference in AUVC CBFV between sampling and replacement in the high position, compared with a 15% difference in the low position. Changes in AUVC during both aspiration and replacement were significantly greater in the highpositioned UACs. No significant changes were noted for pulsatility index throughout the study.

CONCLUSIONS

Blood sampling from UACs produces clinically significant changes in CBFV and may contribute to intraventricular hemorrhage. Blood sampling from low-positioned UACs caused smaller CBFV changes, thus this position may be safer for use in infants at risk for intraventricular hemorrhage.

Inhaled nitric oxide in term infants with hypoxemic respiratory failure

OBJECTIVE

To determine whether inhaled nitric oxide (NO) administered during conventional mechanical ventilation could produce improvements in oxygenation and reduce the incidence of meeting extracorporeal membrane oxygenation (ECMO) criteria in infants with hypoxemia.

DESIGN

Prospective, randomized, controlled trial. Enrolled infants were assigned to conventional treatment with or without adjunctive inhaled NO. Control infants meeting failure criteria (partial pressure of arterial oxygen (PaO2)<80 mm Hg (10.7 kPa)) were allowed to cross over. Caregivers were not masked to group assignment.

SETTING

Neonatal intensive care units at the University of Alabama Hospital and the Children's Hospital of Alabama, October 1993 to May 1994.

PATIENTS

Newborn infants, both term and near-term, with PaO2 less than 100 mm Hg (13.3 kPa) who were receiving mechanical ventilation with 100% oxygen. Exclusion criteria included major congenital anomalies, diaphragmatic hernia, profound asphyxia, and significant bleeding.

INTERVENTIONS

Inhaled NO was initiated in the NO group at a dose of 20 to 40 ppm and advanced stepwise to 80 ppm if PaO2 remained less than 100 mm Hg (13.3 kPa).

OUTCOME MEASURES

Primary outcome variables were treatment failure and meeting of ECMO criteria before crossover. Improvement in oxygenation and ultimate use of ECMO or high-frequency oscillatory ventilation were secondary outcome variables.

RESULTS

Seventeen neonates with hypoxemia were enrolled; 16 had echocardiographic evidence of pulmonary hypertension, and eight had extrapulmonary shunting. At 1 hour of treatment, two infants in the NO group responded with increases in PaO2 of more than 100 mm Hg (13.3 kPa); after crossover, two had increases in PaO2 of more than 10 mm Hg (1.3 kPa) and one control infant had an increase in PaO2 of more than 10 mm Hg (1.3 kPa). All control infants met failure criteria and crossed over to receive NO; two had increases in PaO2 of more than 10 mm Hg (1.3 kPa) with NO treatment. Despite initial responses, all subjects in both groups eventually met failure criteria. There were no differences between groups in primary outcome variables.

CONCLUSIONS

Although inhaled NO produced a transient improvement in oxygenation in some infants, it did not reduce the incidence of meeting ECMO criteria in this population.

Air Emissions from the Manufacture of Inks

Mass balance data are employed to determine VOC emission factors for ink manufacturing processes. The data represent a broad spectrum of case studies in which inputs to ink mixing vessels are weighed both before and after mixing. The difference between pre-mixing and post-mixing weights represent air emissions. In contrast to EPA's estimate of 30 lb of VOC emissions per ton of manufactured ink (contained in the AP-42 emission factors), this work indicates that 44.7 lb/ton is a more accurate emission factor. The new data are expected to have a significant effect on permitting efforts for ink manufacturers as Title V operating permits are prepared.

Treatment of Halogenated Organic Vent Streams for the Reduction of Air Emissions

This work presents a three-stage treatment system to process halogenated organic vent streams for compliance with the Hazardous Organic NESHAP (HON) Rule. The three stages are incineration, energy recovery, and wet scrubbing. In particular, this work concentrates on the design of the scrubber, which the HON Rule states must remove at least 99% of any halogens or hydrogen halides generated during the combustion step. Computerized process simulation was found to be ineffective in designing a scrubber for this application, so laboratory data on the partial pressure of the hydrogen halide species over aqueous solutions was employed. The number of overall gas transfer units required for 99% removal was found to be slightly less than 5, and the overall gas transfer unit height was found to be approximately 0.5 m.

Characterization of an ultraviolet photoreception mechanism in the retina of an amphibian, the axolotl (Ambystoma mexicanum)

Spectral sensitivity measurements from the retina of the Mexican salamander Ambystoma mexicanum (the 'axolotl') were used to provide evidence for and to characterize an amphibian ultraviolet-sensitive photoreception mechanism. Electroretinograms (transretinal voltage responses) were recorded from open eye cup preparations to analyze the spectral sensitivity of the retina. Both dark-adapted and white light-adapted preparations exhibited a peak in sensitivity between 360-370 nm. Under selective chromatic adaptation with long-wavelength light the eye cups continued to exhibit a peak sensitivity around 360 nm. These data confirm the presence of ultraviolet-sensitive cones in the retina of Ambystoma salamanders. The possible relevance of these results to the development and behavior of this group of salamanders is briefly discussed.