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Subacute combined degeneration (SCD) is caused by demyelination of spinal cord white matter secondary to vitamin B12 (cobalamin) deficiency leading to core symptoms of spastic paresis and vibratory and proprioceptive deficits. Most common causes of B12 deficiency revolve around malabsorption and pernicious anemia; however, nitrous oxide (N2O) can also indirectly cause B12 deficiency by inactivating its biologically active form. We report a case of a patient who took advantage of the unregulated N2O market and presented with signs and symptoms of SCD secondary to N2O abuse. Prior to symptom onset, the patient reported approximately 3,000g of N2O inhalation within five days prior to symptom onset in addition to daily use three weeks prior. Work up revealed laboratory and imaging abnormalities consistent with SCD, although B12 levels were normal intrinsic-factor-blocking (IFB) antibodies were present. Appropriate treatment was undertaken, and the patient was followed up at one week and one month with noticeable clinical improvements. Similarities of this patient to literature include the classic presenting symptoms of SCD and the gradual symptomatic improvement with B12 injections and N2O abstinence. This case is remarkable due to SCD occurrence after recreational N2O abuse, objective quantification of N2O intake over a specified time period to induce SCD, occurrence secondary to N2O inhalation, positive IFB antibodies, and symptomatic presentation with B12 values within normal limits. This report highlights the dangers associated with N2O abuse and moving forward awareness of this case can be referenced to aid in educating members of our communities at risk for substance abuse.

Recently, missense mutations in the gene TARDBP encoding TDP-43 have been linked to familial ALS. The discovery of genes encoding these RNA binding proteins, such as TDP-43 and FUS/TLS, raised the notion that altered RNA metabolism is a major factor underlying the pathogenesis of ALS. To begin to unravel how mutations in TDP-43 cause dysfunction and death of motor neurons, investigators have employed both gain- and loss-of-function studies in rodent model systems. Here, we will summarize major findings from the initial sets of TDP-43 transgenic and knockout rodent models, identify their limitations, and point to future directions toward clarification of disease mechanism(s) and testing of therapeutic strategies that ultimately may lead to novel therapy for this devastating disease. This article is part of a Special Issue entitled RNA-Binding Proteins.

γ-Secretase, a multisubunit transmembrane protease comprised of presenilin, nicastrin, presenilin enhancer 2, and anterior pharynx-defective one, participates in the regulated intramembrane proteolysis of Type I membrane proteins including the amyloid precursor protein (APP). Although Aph-1 is thought to play a structural role in the assembly of γ-secretase complex and several transmembrane domains (TMDs) of Aph-1 have been shown to be critical for its function, the importance of the other domains of Aph-1 remains elusive. We screened a series of Aph-1 mutants and focused on nine mutations distributed in six different TMDs of human APH-1aS, assessing their ability to complement mouse embryonic fibroblasts lacking Aph-1. We showed that mutations in TMD4 (G126) and TMD5 (H171) of Aph-1aS prevented the formation of the Nct/Aph-1 subcomplex. Importantly, although mutations in TMD3 (Q83/E84/R85) and TMD6 (H197) of APH-1aS did not affect Nct/Aph-1 subcomplex formation, both mutations prevented further association/endoproteolysis of PS1. We propose a model that identifies critical TMDs of Aph-1 for associations with Nct and PS for the stepwise assembly of γ-secretase components.

Over the past three decades, significant progress has been made in understanding the neurobiology of Alzheimer's disease. In recent years, the first attempts to implement novel mechanism-based treatments brought rather disappointing results, with low, if any, drug efficacy and significant side effects. A discrepancy between our expectations based on preclinical models and the results of clinical trials calls for a revision of our theoretical views and questions every stage of translation—from how we model the disease to how we run clinical trials. In the following sections, we will use some specific examples of the therapeutics from acetylcholinesterase inhibitors to recent anti-Aβ immunization and γ-secretase inhibition to discuss whether preclinical studies could predict the limitations in efficacy and side effects that we were so disappointed to observe in recent clinical trials. We discuss ways to improve both the predictive validity of mouse models and the translation of knowledge between preclinical and clinical stages of drug development.

β-Site amyloid precursor protein (APP) cleaving enzyme 1 (BACE1) is an aspartyl protease best known for its role in generating the amyloid-β peptides that are present in plaques of Alzheimer's disease. BACE1 has been an attractive target for drug development. In cultured embryonic neurons, BACE1-cleaved N-terminal APP is further processed to generate a fragment that can trigger axonal degeneration, suggesting a vital role for BACE1 in axonal health. In addition, BACE1 cleaves neuregulin 1 type III, a protein critical for myelination of peripheral axons by Schwann cells during development. Here, we asked whether axonal degeneration or axonal regeneration in adult nerves might be affected by inhibition or elimination of BACE1. We report that BACE1 knock-out and wild-type nerves degenerated at a similar rate after axotomy and to a similar extent in the experimental neuropathies produced by administration of paclitaxel and acrylamide. These data indicate N-APP is not the sole culprit in axonal degeneration in adult nerves. Unexpectedly, however, we observed that BACE1 knock-out mice had markedly enhanced clearance of axonal and myelin debris from degenerated fibers, accelerated axonal regeneration, and earlier reinnervation of neuromuscular junctions, compared with littermate controls. These observations were reproduced in part by pharmacological inhibition of BACE1. These data suggest BACE1 inhibition as a therapeutic approach to accelerate regeneration and recovery after peripheral nerve damage.

Morphological evolution of heteroepitaxial nanoislands toward equilibrium (coarsening) is computed using the detailed continuum model that incorporates the quantum size effect. Results reveal the metastability of the "magic" heights, show the morphological transitions and the surface diffusion routes by which a quantum island reaches its stable height, and provide the coarsening laws for the island density and area, thus clarifying the kinetic morphology pathways in the growth of an ultrathin metal films., Accepted for publication in the Journal of Applied Physics

TAR DNA-binding protein-43 (TDP-43), a DNA/RNA-binding protein involved in RNA transcription and splicing, has been associated with the pathophysiology of neurodegenerative diseases, including ALS. However, the function of TDP-43 in motor neurons remains undefined. Here we use both gain- and loss-of-function approaches to determine roles of TDP-43 in motor neurons. Mice expressing human TDP-43 in neurons exhibited growth retardation and premature death that are characterized by abnormal intranuclear inclusions composed of TDP-43 and fused in sarcoma/translocated in liposarcoma (FUS/TLS), and massive accumulation of mitochondria in TDP-43-negative cytoplasmic inclusions in motor neurons, lack of mitochondria in motor axon terminals, and immature neuromuscular junctions. Whereas an elevated level of TDP-43 disrupts the normal nuclear distribution of survival motor neuron (SMN)-associated Gemini of coiled bodies (GEMs) in motor neurons, its absence prevents the formation of GEMs in the nuclei of these cells. Moreover, transcriptome-wide deep sequencing analysis revealed that a decrease in abundance of neurofilament transcripts contributed to the reduction of caliber of motor axons in TDP-43 mice. In concert, our findings indicate that TDP-43 participates in pathways critical for motor neuron physiology, including those that regulate the normal distributions of SMN-associated GEMs in the nucleus and mitochondria in the cytoplasm.

β-Amyloid (Aβ) pathology is an essential pathogenic component in Alzheimer's disease (AD). However, the significance of Aβ pathology, including Aβ deposits/oligomers and glial reactions, to neurodegeneration is unclear. In particular, despite the Aβ neurotoxicity indicated byin vitrostudies, mouse models with significant Aβ deposition lack robust and progressive loss of forebrain neurons. Such results have fueled the view that Aβ pathology is insufficient for neurodegenerationin vivo. In this study, because monoaminergic (MAergic) neurons show degenerative changes at early stages of AD, we examined whether theAPPswe/PS1ΔE9mouse model recapitulates progressive MAergic neurodegeneration occurring in AD cases. We show that the progression forebrain Aβ deposition in theAPPswe/PS1ΔE9model is associated with progressive losses of the forebrain MAergic afferents. Significantly, axonal degeneration is associated with significant atrophy of cell bodies and eventually leads to robust loss (∼50%) of subcortical MAergic neurons. Degeneration of these neurons occurs without obvious local Aβ or tau pathology at the subcortical sites and precedes the onset of anxiety-associated behavior in the mice. Our results show that a transgenic mouse model of Aβ pathology develops progressive MAergic neurodegeneration occurring in AD cases.

β-Site APP-cleaving enzyme 1 (BACE1) is required for the penultimate cleavage of the amyloid-β precursor protein (APP) leading to the generation of amyloid-β peptides that is central to the pathogenesis of Alzheimer's disease. In addition to its role in endoproteolysis of APP, BACE1 participates in the proteolytic processing of neuregulin 1 (NRG1) and influences the myelination of central and peripheral axons. Although NRG1 has been genetically linked to schizophrenia and NRG1 +/− mice exhibit a number of schizophrenia-like behavioral traits, it is not known whether altered BACE1-dependent NRG1 signaling can cause similar behavioral abnormalities. To test this hypothesis, we analyze the behaviors considered to be rodent analogs of clinical features of schizophrenia in BACE1 −/− mice with impaired processing of NRG1. We demonstrate that BACE1 −/− mice exhibit deficits in prepulse inhibition, novelty-induced hyperactivity, hypersensitivity to a glutamatergic psychostimulant (MK-801), cognitive impairments, and deficits in social recognition. Importantly, some of these manifestations were responsive to treatment with clozapine, an atypical antipsychotic drug. Moreover, although the total amount of ErbB4, a receptor for NRG1 was not changed, binding of ErbB4 with postsynaptic density protein 95 (PSD95) was significantly reduced in the brains of BACE1 −/− mice. Consistent with the role of ErbB4 in spine morphology and synaptic function, BACE1 −/− mice displayed reduced spine density in hippocampal pyramidal neurons. Collectively, our findings suggest that alterations in BACE1-dependent NRG1/ErbB4 signaling may participate in the pathogenesis of schizophrenia and related psychiatric disorders.

Loss-of-function mutations in the DJ-1 gene account for an autosomal recessive form of Parkinson's disease (PD). To investigate the physiological functions of DJ-1 in vivo, we generated DJ-1 knockout (DJ-1(-/-)) mice. Younger (

Purpose: Ischemic stroke patients, who meet criteria to be administered t-PA, should receive a patient-focused effort that advocates for quality, efficacious treatment. It’s essential to continuously evaluate the impact that a model of care delivery has on clinical outcomes. Healthcare reform may dictate utilization of current resources and often allocation of those resources are re-aligned to meet financial targets. The model of care delivery referenced in this study includes primary responders on a code stroke team that have transitioned from a unit based resource to an emergency room resource. Quality outcomes are a priority and overcoming obstacles to prevent delays in meeting the national benchmark of door to needle time in less than 60 minutes requires enhanced partnerships. The purpose of this study was to determine the effects that a model of care delivery for acute stroke response had on door to needle time and identify the impact from utilization of value stream mapping. Methods: Retrospective chart reviews were conducted on stroke patients that received t-PA over a 5 year period. Comparative analysis of all response times were reviewed for trends and opportunities that may have also been impacted by the model of care delivery. Immediate review and feedback on every case served as a catalyst for quality improvement, engaging all providers to implement changes that would improve door to needle times. Response time data was analyzed to determine if there was statistical significance, such that all opportunities for improvement to reduce needle to door time to < 60 minutes could be addressed with action plans. Results: Percentage compliance of door to needle time within 60 minutes increased from 17% to 63% during the study period. Opportunities to further reduce door to needle times reveal potential decrease of key response times by approximately 20 minutes. This is evidenced by continued improvement in the average door to needle time by 15 minutes during the study period. Conclusion: Transition of care delivery models with ownership and team engagement can result in a paradigm shift that indicates effective action plans for quality improvement in door to needle times. Further insight from value mapping serves as a guide for lean processes.

Significant progress has been made since the 1980s in understanding the neurobiology of Alzheimer disease (AD). The clinical syndrome of AD results from synaptic dysfunction and death of neurons in specific brain regions and circuits, particularly populations of nerve cells subserving memory and cognition. The pathological hallmarks are the extracellular deposition of β-pleated assemblies of Aβ-peptide (amyloid plaques) and intracellular aggregates of hyperphosphorylated tau protein (neurofibrillary tangles). Utilization of transgenic models of AD has advanced understanding of the pathogenesis of this disease and resulted in the discovery of therapeutic targets. The first attempts to implement novel antiamyloid treatments in mild to moderate AD had disappointing results, suggesting that therapy should be given much earlier in the course of the disease. Recognition that pathophysiological processes of AD begin decades before clinical symptoms appear calls for the development of tools for early diagnosis (imaging and biomarkers) and early treatment.

A transmembrane aspartyl protease termed β-site APP cleavage enzyme 1 (BACE1) that cleaves the amyloid-β precursor protein (APP), which is abundant in neurons, is required for the generation of amyloid-β (Aβ) peptides implicated in the pathogenesis of Alzheimer's disease (AD). We now demonstrate that BACE1, enriched in neurons of the CNS, is a major determinant that predisposes the brain to Aβ amyloidogenesis. The physiologically high levels of BACE1 activity coupled with low levels of BACE2 and α-secretase anti-amyloidogenic activities in neurons is a major contributor to the accumulation of Aβ in the CNS, whereas other organs are spared. Significantly, deletion ofBACE1inAPPswe;PS1ΔE9mice prevents both Aβ deposition and age-associated cognitive abnormalities that occur in this model of Aβ amyloidosis. Moreover, Aβ deposits are sensitive toBACE1dosage and can be efficiently cleared from the CNS whenBACE1is silenced. However,BACE1null mice manifest alterations in hippocampal synaptic plasticity as well as in performance on tests of cognition and emotion. Importantly, memory deficits but not emotional alterations inBACE1–/–mice are prevented by coexpressingAPPswe;PS1ΔE9transgenes, indicating that other potential substrates of BACE1 may affect neural circuits related to emotion. Our results establish BACE1 and APP processing pathways as critical for cognitive, emotional, and synaptic functions, and future studies should be alert to potential mechanism-based side effects that may occur with BACE1 inhibitors designed to ameliorate Aβ amyloidosis in AD.

The principal goals of investigating the models for Alzheimer's disease (AD) are to reproduce the amyloid/tau-related pathologies and the memory deficits occurring in patients. Recent models do allow crucial examinations of disease mechanisms and will be of great value in testing new therapeutic strategies including inhibition of BACE1 and β-secretase activities, modulators of γ-secretase and Aβ immunotherapies. Presently available mouse models can achieve a high degree of predictive validity for positive outcomes of experimental therapies, but they have been less successful in identifying potential adverse outcomes that can occur in human trials.

APH-1 (anterior pharynx defective) along with nicastrin and PEN-2 (presenilin enhancer) are essential components of the presenilin (PS)-dependent γ-secretase complex. There exist three murineAph-1alleles termedAph-1a,Aph-1b, andAph-1cthat encode four distinct APH-1 isoforms: APH-1aL and APH-1aS derived from differential splicing ofAph-1a, APH-1b, and APH-1c. To determine the contributions of mammalian APH-1 homologs in formation of functional γ-secretase complexes, we generatedAph-1a-/-mice and derived immortalized fibroblasts from these embryos. Compared with littermate controls, the development ofAph-1a-/-embryos was dramatically retarded by embryonic day 9.5 and exhibited patterning defects that resemble, but are not identical to, those ofNotch1,nicastrin, orPSnull embryos. Moreover, in immortalizedAph-1a-/-fibroblasts, the levels of nicastrin, PS fragments, and PEN-2 were dramatically decreased. Consequently, deletion ofAph-1aresulted in significant reduction in levels of high-molecular-weight γ-secretase complex and secretion of β-amyloid (Aβ). Importantly, complementation analysis revealed that all mammalian APH-1 isoforms were capable of restoring the levels of nicastrin, PS, and PEN-2, as well as Aβ secretion inAph-1a-/-cells. Together, our findings establish that APH-1a is the major mammalian APH-1 homolog present in PS-dependent γ-secretase complexes during embryogenesis and support the view that mammalian APH-1 isoforms define a set of distinct functional γ-secretase complexes.

Biochemical and genetic abnormalities of alpha-synuclein (alpha-Syn) are implicated in the pathogenesis of Parkinson's disease (PD) and other alpha-synucleinopathies. The abnormal intraneuronal accumulations of alpha-Syn in Lewy bodies (LBs) and Lewy neurites (LNs) have implicated defects in axonal transport of alpha-Syn in the alpha-synucleinopathies. Using human (Hu) alpha-Syn transgenic (Tg) mice, we have examined whether familial PD (FPD)-linked mutations (A30P and A53T) alter axonal transport of Hualpha-Syn. Our studies using peripheral nerves show that Hualpha-Syn and Moalpha-Syn are almost exclusively transported in the slow component (SC) of axonal transport and that the FPD-linked alpha-Syn mutations do not have obvious effects on the axonal transport of alpha-Syn. Moreover, older pre-symptomatic A53T Hualpha-Syn Tg mice do not show gross alterations in the axonal transport of alpha-Syn and other proteins in the SC, indicating that the early stages of alpha-synucleinopathy in A53T alpha-Syn Tg mice are not associated with gross alterations in the slow axonal transport. However, the axonal transport of alpha-Syn slows significantly with aging. Because the rate of axonal transport affects the stability and accumulation of proteins in axons, age-dependent-slowing alpha-Syn is a likely contributor to axonal aggregation of alpha-Syn in alpha-synucleinopathy.

In this study, we show that removal of entorhinal cortex (ERC) afferents to hippocampus reduces levels of presenilin 1 (PS1) in the dentate gyrus of APPswe/PS1ΔE9 transgenic (Tg) mice. PS1 immunoreactivity on the deafferented dentate gyrus decreases by approximately 25% and 50%, 2 and 4 weeks post-lesion compared to the contralateral side; by Western blotting, there is an approximately 40% decrease of the 43 kDa (full length) PS1 and an approximately 80% decrease of the 28 kDa (N-terminal fragment) PS1 on the lesioned dentate gyrus. Levels of β-site APP Cleavage Enzyme 1 (BACE1) immunoreactivity also decrease by approximately 50% and 65% 2 and 4 weeks post-lesion. Together, these data demonstrate that PS1 and BACE1 are transported from the entorhinal cortex to the hippocampus via axons of the perforant pathway.

The present study was designed to examine whether brain inflammation caused by systemic administration of lipopolysaccharides (LPS) alters the expression/processing of amyloid precursor protein (APP) and increases the generation of amyloid beta peptide (Abeta). APPswe transgenic (Tg) mice were treated with either LPS or phosphate-buffered saline (PBS). In LPS-treated APPswe mice, Abeta1-40/42 was 3-fold and APP was 1.8-fold higher than those in PBS-treated mice (P < 0.05) by ELISA, Western blots and immunoprecipitation-mass spectrometry (IP-MS) ProteinChip analysis. Numbers of Abeta- and APP-immunoreactive neurons (Abeta(+) and APP(+) neurons) increased significantly in LPS-treated APPswe mice; APP(+) and Abeta(+) neurons in neocortex were associated with an increased number of F4/80-immunoreactive microglia (F4/80(+) microglia) in their anatomical environment. Our findings demonstrate that experimental neuroinflammation increases APP expression/processing and causes intracellular accumulation of Abeta. It remains to be seen whether such events can cause neuronal dysfunction/degeneration and, with time, lead to extracellular Abeta deposits, as they occur in Alzheimer's disease.

Recent studies indicate that nicastrin (NCT) and presenilins form functional components of a multimeric gamma-secretase complex required for the regulated intramembraneous proteolysis of Notch and beta-amyloid (Abeta) precursor protein (APP). To determine whether nicastrin is required for proteolytic processing of Notch and APP in mammals and the role of nicastrin in presenilin/gamma-secretase complex assembly, we generated nicastrin-deficient (NCT-/-) mice and derived fibroblasts from NCT-/- embryos. Nicastrin-null embryos died by embryonic day 10.5 and exhibited several patterning defects, including abnormal somite segmentation, phenotypes that are reminiscent of embryos lacking Notch1 or both presenilins. Importantly, secretion of Abeta peptides is abolished in NCT-/- fibroblasts, whereas it is reduced by approximately 50% in NCT+/- cells; the failure to generate Abeta peptides in NCT-/- cells is accompanied by destabilization of the presenilin/gamma-secretase complex and accumulation of APP-C-terminal fragments. Moreover, APP trafficking analysis in NCT-/- fibroblasts revealed a significant delay in the rate of APP reinternalization compared with that of control cells. Together, these results establish that nicastrin is an essential component of the multimeric gamma-secretase complex in mammals required for both gamma-secretase activity and APP trafficking and suggest that nicastrin may be a valuable therapeutic target for Alzheimer's disease.

Amyloid deposition appears to be an early and crucial event in Alzheimer's disease (AD). To generate animal models of AD, mice expressing full-length amyloid precursor protein (APP), with mutations linked to FAD, have been created. These animals exhibit abnormalities characteristic of AD, including deposits of beta-amyloid (Abeta), neuritic plaques, and glial responses. In studies of cognition in these animals, there have been several reports of memory disturbances well before the appearance of amyloid deposits. We have developed two distinct lines of transgenic mice (C3-3 and E1-2) that express the "Swedish" variant of APP (APP(SWE)) at levels that are approximately three-fold higher than endogenous mouse APP. Both lines have been backcrossed to C57BL/6J mice for 10 generations. Here, we use longitudinal and cross-sectional studies to evaluate the cognitive performance of our animals, where the concentration of Abeta1-42 in brain increases with aging from low levels (2-10 pmol/g) at 6-14 months of age to relatively high levels (60-100 pmol/g) at 24-26 months, when deposits of Abeta were beginning to form. When 12-month-old mice were tested in tasks that assess reference and working memory, transgenic mice from both lines could not be distinguished from nontransgenic littermates. Further study of 24- to 26-month-old transgenic mice (C3-3 line) found no evidence of memory impairment despite the presence of high levels of human Abeta (60-100 pmol/g). Thus, the expression of APP(SWE) at approximately three-fold over endogenous levels, which is sufficient to induce amyloid deposition at advanced ages, does not significantly erode cognitive performance in aged mice.

We have identified the regional distributions and developmental expression of NMDA-receptor proteins NR2A and NR2B in rat CNS, using two subunit-specific affinity-purified polyclonal antibodies that recognize NR2A and NR2B. In western blots of cells transfected with NR2A or NR2B cDNAs, and of brain homogenates, each antibody detects a single predominant 172-kDa protein corresponding to its homologous subunit. Both subunits are glycoproteins that are enriched in synaptic membranes. In adult rat CNS, NR2A and NR2B are enriched in cortex and hippocampus but are present in other forebrain regions. In hindbrain, NR2A is present at low levels but NR2B is barely detectable. These subunits are differentially expressed in postnatal CNS development. In cortex and striatum, NR2A is absent at birth but expression increases thereafter, whereas NR2B is expressed at nearly adult levels during forebrain development. In hindbrain, low levels of NR2A are present throughout development, whereas NR2B is expressed only transiently in the first postnatal weeks. These results suggest that native NMDA receptors are modulated by NR2A and NR2B in adult forebrain but not appreciably in hindbrain. In contrast, during early postnatal development, NR2B may have a more dominant role than NR2A in modulating NMDA receptors throughout the CNS. Thus, transient changes in NMDA-receptor function may occur during maturation of certain neuronal and/or glial populations via differential expression of NR2A and NR2B subunits.

Copper-mediated oxidative damage is proposed to play a critical role in the pathogenesis of Cu/Zn superoxide dismutase (SOD1)-linked familial amyotrophic lateral sclerosis (FALS). We tested this hypothesis by ablating the gene encoding the copper chaperone for SOD1 (CCS) in a series of FALS-linked SOD1 mutant mice. Metabolic 64Cu labeling in SOD1-mutant mice lacking the CCS showed that the incorporation of copper into mutant SOD1 was significantly diminished in the absence of CCS. Motor neurons in CCS-/- mice showed increased rate of death after facial nerve axotomy, a response documented for SOD1-/- mice. Thus, CCS is necessary for the efficient incorporation of copper into SOD1 in motor neurons. Although the absence of CCS led to a significant reduction in the amount of copper-loaded mutant SOD1, however, it did not modify the onset and progression of motor neuron disease in SOD1-mutant mice. Hence, CCS-dependent copper loading of mutant SOD1 plays no role in the pathogenesis of motor neuron disease in these mouse models.

Protein adducts of the lipid peroxidation product trans-4-hydroxy-2-nonenal (HNE) are features of oxidative damage in neuronal cell bodies in Alzheimer's disease but are also seen in axons of normal as well as diseased individuals. In this study, focusing on the axons of the mouse sciatic nerve, we found that HNE adducts characterize axons of mice from birth to senility. Immunoblots of axonal proteins showed that HNE adducts are only detected in neurofilament heavy subunit (NFH) and, to a lesser extent, neurofilament medium subunit (NFM), both lysine-rich proteins, consistent with the adducts being limited to lysine residues. In vitro, HNE treatment of permeabilized sciatic nerve showed the same specificity, i.e. NFH and NFM are the only proteins that reacted with HNE, providing they are phosphorylated. Quantitative immunoblot analysis of two strains of mice ages 1-33 months showed that the levels of HNE adducts on NFH are consistent throughout life. Additionally, mice transgenic for human superoxide dismutase-1 with G85R mutation show no difference in HNE adduction to NFH compared with controls. Taken together, these studies indicate that HNE adduction to NFH is physiological, and its constancy from birth to senility as well as its dependence on phosphorylation argues that NFH and NFM modification may play a role in protecting the membrane-rich axon from toxic aldehydes resulting from oxidative damage.

Purpose: To determine whether the stroke alert process results in improved outcomes, as reflected in door to lytic times and other outcome measures. Introduction: The diagnosis and treatment of stroke is time-sensitive and should be inclusive of all seven D’s in the “chain of survival” - Detection, Dispatch, Delivery, Door, Data, Decision and Drug (Adams, Stroke, 2007). Early stroke activation is part of the “Delivery” which incorporates transport and management by Emergency Medical Services (EMS). Clinical suspicion of stroke by EMS resulted in a process of early activation which was labeled “Stroke Alert.” This expedited the code stroke process upon arrival, preparing the hospital based stroke team to provide immediate triage and evaluation. The goal was to improve clinical efficiency and possibly clinical outcomes. Methods: • Implementation of a notification process from EMS to ED - Stroke Alert • Incorporated Stroke Alert to include Stroke Response Team (SRT) nurses January 22, 2011 • Retrospective review of internal stroke database (January 22, 2011 to July 2013) for comparative analysis of Stroke Alerts called versus those where no stroke alert was called • Evaluate clinical outcomes directly related to Stroke Alert process Results: From January 22, 2011 to July 2013: Stroke Alert Called: • 37 t-PA patients and 14 of those, 37.8%, met the 60 minute benchmark • Average Door to Lytic time - 65 minutes Stroke Alert NOT Called: • 35 t-PA patients and 10 of those, 28.6% met the 60 minute benchmark • Average Door to Lytic time - 79 minutes Conclusions: The ability for a SRT to meet the golden hour of stroke benchmark occurs more frequently when a Stroke Alert is called to the SRT nurse. Future plans include review of stroke severity scores, length of stay (LOS), and discharge disposition, to determine the impact a Stroke Alert may have on clinical outcomes.

The mechanisms leading to neurodegeneration in ALS (amyotrophic lateral sclerosis) are not well understood, but cytosolic protein aggregates appear to be common in sporadic and familial ALS as well as transgenic mouse models expressing mutant Cu/Zn superoxide dismutase (SOD1). In this study, we systematically evaluated the presence of these aggregates in three different mouse models (G93A, G85R, and G37R SOD1) and compared these aggregates to those seen in cases of sporadic and familial ALS. Inclusions and loss of motor neurons were observed in spinal cords of all of these three mutant transgenic lines. Since a copper-mediated toxicity hypothesis has been proposed to explain the cytotoxic gain-of-function of mutant SOD1, we sought to determine the involvement of the copper chaperone for SOD1 (CCS) in the formation of protein aggregates. Although all aggregates contained CCS, SOD1 was not uniformly found in the inclusions. Similarly, CCS-positive skein-like inclusions were rarely seen in ALS neurons. These studies do not provide strong evidence for a causal role of CCS in aggregate formation, but they do suggest that protein aggregation is a common event in all animal models of the disease. Selected proteins, such as the glutamate transporter GLT-1, were not typically observed within the inclusions. Most inclusions were positively stained with antibodies recognizing ubiquitin, proteasome, Hsc70 in transgenic lines, and some Hsc70-positive inclusions were detected in sporadic ALS cases. Overall, these observations suggest that inclusions might be sequestered into ubiquitin-proteasome pathway and some chaperone proteins such as Hsc70 may be involved in formation and/or degradation of these inclusions.

Parkinson's disease (PD) is the second most common neurological cause of death, after Alzheimer's disease, in elderly people. PD is characterized by a variety of motoric dysfunctions resulting from the loss of striatal dopamine, which accompany progressive degeneration of dopaminergic neurons in the substantia nigra. While the causes of PD remain elusive in most cases, recent molecular genetic studies have linked mutations in the α-synuclein gene with a rare form of familial PD and mutations in the parkins gene with an autosomal recessive form of familial PD. Identification of these genes is allowing for creation of genetic models where in vivo degenerative processes can be studied. In particular, various transgenic animals expressing human α-synuclein variants have demonstrated that α-synuclein abnormalities can lead to neurodegenerative changes in vivo. These and other genetic models of nigrostriatal degeneration will allow investigators to define in vivo cellular mechanisms that are relevant to PD pathogenesis.