A Hemimysis-driven novel ecosystem at a modified rubble-mound breakwater: An Engineering With Nature® Demonstration Project.

The US Army Corps of Engineers (USACE) repairs aging breakwater structures as part of routine maintenance to maintain safe navigation in Great Lakes commercial ports. A USACE repair to an existing breakwater structure in Milwaukee Harbor (WI) implementing Engineering With Nature (EWN) principles created complex rocky habitat by strategically placing cobble-sized stone over conventional 5.4 to 9.1 metric ton boulders, thus creating "control" (boulder) and "treatment" (cobble) habitats. We evaluated the resultant nature-based breakwater (NBBW) developing food web versus an adjacent reference site on the same breakwater and determined that, unexpectedly, locally abundant Hemimysis anomala were impacting the food-web dynamics and feeding ecology of fishes occupying the structure. Fish and forage communities were sampled using gillnets, night scuba diving surveys, rock collections, and a novel trap to capture invertebrates. The resultant NBBW became home to a prolific population of nonindigenous Hemimysis, with indications that they were more abundant on cobble versus boulders, based on rainbow smelt feeding. This lithophilic/cave swelling mysid provided an important new food resource in Milwaukee Harbor for two introduced pelagic prey fishes: alewife (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax). Gillnetting and night scuba diving surveys confirmed that rainbow smelt preferred to forage on the cobble section (p < 0.05). Hemimysis were also the primary food item consumed by nearshore game fishes such as young-of-the-year (YOY) yellow perch (Perca flavescens), YOY largemouth bass (Micropterus salmoides), and juvenile rock bass (Ambloplites rupestris). We propose that those breakwaters that harbor abundant Hemimysis constitute novel ecosystems (ecosystems that include both native and non-native biota) that might benefit harbor fisheries if well-managed. This project demonstrated how a low-cost design modification could be applied during the repair of rubble-mound, breakwater structures to achieve benefits beyond safe navigation. Integr Environ Assess Manag 2022;18:49-62. Published 2021. This article is a US Government work and is in the public domain in the USA.

Decreasing referrals to transient ischaemic attack clinics during the COVID-19 outbreak: results from a multicentre cross-sectional survey.

OBJECTIVE: The COVID-19 pandemic is having major implications for stroke care with a documented significant fall in hospital acute stroke admissions. We investigated whether COVID-19 has resulted in a decreased number of referrals to the transient ischaemic attack (TIA) clinics across the North West London region. SETTING AND DESIGN: All the TIA clinical leads of the North West London region received an invitation by email to participate in an online survey in May 2020. The survey questionnaire aimed to assess the number of patients with suspected TIA consecutively referred to each of the TIA clinics of the North West London region between 1 March and 30 April 2020, the COVID-19 period, and between 1 March and 30 April 2019. RESULTS: We had a response rate of 100%. During the COVID-19 period, the TIA clinics of the North West London region received 440 referrals compared with 616 referrals received between 1 March and 30 April 2019 with a fall in the number of the referrals by 28.6%. In April 2020 compared with April 2019, the number of the referrals declined by 40.1%. CONCLUSIONS: This multicentre analysis documented a significant reduction in the number of patients referred with suspected TIA to the specialised rapid access outpatient clinics in the North West London region during the COVID-19 pandemic. Future studies are needed to confirm our findings and to better characterise the incidence of cerebrovascular disease during the COVID-19 pandemic.

Species identity matters when interpreting trophic markers in aquatic food webs.

In aquatic systems, food web linkages are often assessed using diet contents, stable isotope ratios, and, increasingly, fatty acid composition of organisms. Some correlations between different trophic metrics are assumed to be well-supported; for example, particular stable isotope ratios and fatty acids seem to reflect reliance on benthic or pelagic energy pathways. However, understanding whether the assumed correlations between different trophic metrics are coherent and consistent across species represents a key step toward their effective use in food web studies. To assess links among trophic markers, we compared relationships between major diet components, fatty acids, and stable isotope ratios in three fishes: yellow perch (Perca flavescens), round goby (Neogobius melanostomus), and spottail shiner (Notropis hudsonius) collected from nearshore Lake Michigan. Yellow perch and spottail shiner are native in this system, while round goby are a relatively recent invader. We found some evidence for agreement between different trophic metrics, especially between diet components, n-3:n-6 fatty acid ratios, and stable isotope ratios (δ13C and δ15N). However, we also observed significant variation in observed relationships among markers and species, potentially due to taxonomic variation in the specific diet items consumed (e.g., chydorid microcrustaceans and Dreissena mussels) and species-specific biochemical processes. In many of these latter cases, the invasive species differed from the native species. Understanding the effects of taxonomic variation on prey and predator signatures could significantly improve the usefulness of fatty acids in food web studies, whereas diet contents and stable isotopes appear to be reliable indicators of trophic niche in aquatic food webs.

Device closure for patent foramen ovale following cryptogenic stroke: a survey of current practice in the UK.

Patent foramen ovale (PFO) closure for cryptogenic stroke remains controversial due to a lack of conclusive randomised controlled data. Many experts feel PFO closure is indicated in selected cases; however, national and international guideline recommendations differ. We surveyed the UK cardiologists, stroke physicians and neurologists, seeking to determine specialist interpretation of the evidence base, and to gain an insight into the current UK practice. The British Cardiac Society and British Society of Stroke physicians distributed our survey which was performed using an online platform. 120 physicians (70 stroke physicians, 23 neurologists, 27 cardiologists) completed the survey. Most (89%) felt PFO closure should be considered in selected patients. Atrial fibrillation (86.6%), significant carotid stenosis (86.6%), diabetes (38.4%) and hypertension (36.6%) were considered exclusion criteria for cryptogenic stroke diagnosis. More stroke physicians than cardiologists considered an age cut-off when considering PFO as the stroke aetiology (70.4%vs 54.5%p=0.04). Anatomical features felt to support PFO closure were aneurysmal septum (89.6%), shunt size (73.6%), prominent Eustachian valve (16%). 60% discuss patients in multidisciplinary meetings prior to PFO closure, with more cardiologists than stroke physicians/neurologists favouring this approach (76.9% vs 54.8%; p=0.05). After PFO closure, patients receive Clopidogrel (72.3%), aspirin (50%) or anticoagulants (17%). 63.2% continue therapy for a limited period after PFO closure, while 34% prefer life-long therapy (14.8% cardiologists vs 40.5% non-cardiologists; p=0.02). While experts support selective PFO closure in cryptogenic stroke, current practice remains variable with significant differences in perceptions of cardiologists and neurologists/stroke physicians.

Regularity underlies erratic population abundances in marine ecosystems.

The abundance of a species' population in an ecosystem is rarely stationary, often exhibiting large fluctuations over time. Using historical data on marine species, we show that the year-to-year fluctuations of population growth rate obey a well-defined double-exponential (Laplace) distribution. This striking regularity allows us to devise a stochastic model despite seemingly irregular variations in population abundances. The model identifies the effect of reduced growth at low population density as a key factor missed in current approaches of population variability analysis and without which extinction risks are severely underestimated. The model also allows us to separate the effect of demographic stochasticity and show that single-species growth rates are dominantly determined by stochasticity common to all species. This dominance-and the implications it has for interspecies correlations, including co-extinctions-emphasizes the need for ecosystem-level management approaches to reduce the extinction risk of the individual species themselves.

Nearshore energy subsidies support Lake Michigan fishes and invertebrates following major changes in food web structure.

Aquatic food webs that incorporate multiple energy channels (e.g., nearshore benthic and pelagic) with varying productivity and turnover rates convey stability to biological communities by providing independent energy sources. Within the Lake Michigan food web, invasive dreissenid mussels have caused rapid changes to food web structure and potentially altered the channels through which consumers acquire energy. We used stable C and N isotopes to determine how Lake Michigan food web structure has changed in the past decade, coincident with the expansion of dreissenid mussels, decreased pelagic phytoplankton production, and increased nearshore benthic algal production. Fish and invertebrate samples collected from sites around Lake Michigan were analyzed to determine taxa-specific 13C:12C (delta13C) and 15N:14N (delta15N) ratios. Sampling took place during two distinct periods, 2002-2003 and 2010-2012, that spanned the period of dreissenid expansion, and included nearshore, pelagic and profundal fish and invertebrate taxa. The magnitude and direction of the delta13C shift indicated significantly greater reliance upon nearshore benthic energy sources among nearly all fish taxa as well as profundal invertebrates following dreissenid expansion. Although the mechanisms underlying this delta13C shift likely varied among species, possible causes include the transport of benthic algal production to offshore waters and increased feeding on nearshore prey items by pelagic and profundal species. delta15N shifts were more variable and of smaller magnitude across taxa, although declines in delta15N among some pelagic fishes suggest a shift to alternative prey resources. Lake Michigan fishes and invertebrates appear to have responded to dreissenid-induced changes in nutrient and energy pathways by switching from pelagic to alternative nearshore energy subsidies. Although large shifts in energy allocation (i.e., pelagic to nearshore benthic) resulting from invasive species appear to affect total production at upper trophic levels, changes in trophic structure and utilization of novel energy pathways may help to stabilize food webs following species invasions.

Extended phenotypic spectrum of KIF5A mutations: From spastic paraplegia to axonal neuropathy.

OBJECTIVE: To establish the phenotypic spectrum of KIF5A mutations and to investigate whether KIF5A mutations cause axonal neuropathy associated with hereditary spastic paraplegia (HSP) or typical Charcot-Marie-Tooth disease type 2 (CMT2). METHODS: KIF5A sequencing of the motor-domain coding exons was performed in 186 patients with the clinical diagnosis of HSP and in 215 patients with typical CMT2. Another 66 patients with HSP or CMT2 with pyramidal signs were sequenced for all exons of KIF5A by targeted resequencing. One additional patient was genetically diagnosed by whole-exome sequencing. RESULTS: Five KIF5A mutations were identified in 6 unrelated patients: R204W and D232N were novel mutations; R204Q, R280C, and R280H have been previously reported. Three patients had CMT2 as the predominant and presenting phenotype; 2 of them also had pyramidal signs. The other 3 patients presented with HSP but also had significant axonal neuropathy or other additional features. CONCLUSION: This is currently the largest study investigating KIF5A mutations. By combining next-generation sequencing and conventional sequencing, we confirm that KIF5A mutations can cause variable phenotypes ranging from HSP to CMT2. The identification of mutations in CMT2 broadens the phenotypic spectrum and underlines the importance of KIF5A mutations, which involve degeneration of both the central and peripheral nervous systems and should be tested in HSP and CMT2.

Sniffing out a hidden cause of breathlessness.

A 78-year-old man presented with severe exertional dyspnoea. He suffered from mild chronic obstructive pulmonary disease, congestive cardiac failure and seropositive myasthaenia gravis. Clinical examination of his chest and heart were unremarkable but he had speech dyspnoea and was unable to count to 20 in a single breath. Consecutive sniff nasal inspiratory measurements (SNIP) fell from 55 to 33 cm H2O and forced vital capacity (FVC) fell from 3.4 to 2.4 L. A diagnosis of myasthenic crisis was carried out and treatment with non-invasive ventilation, intravenous immunoglobulis and high-dose oral prednisolone was initiated. The patient responded well and was discharged following a short period of rehabilitation. A high index of suspicion and a careful clinical examination with the help of two simple bedside tests, FVC and SNIP, allowed correct and timely treatment of his condition.

Multi-criteria decision analysis of test endpoints for detecting the effects of endocrine active substances in fish full life cycle tests.

Fish full life cycle (FFLC) tests are increasingly required in the ecotoxicological assessment of endocrine active substances. However, FFLC tests have not been internationally standardized or validated, and it is currently unclear how such tests should best be designed to provide statistically sound and ecologically relevant results. This study describes how the technique of multi-criteria decision analysis (MCDA) was used to elicit the views of fish ecologists, aquatic ecotoxicologists and statisticians on optimal experimental designs for assessing the effects of endocrine active chemicals on fish. In MCDA qualitative criteria (that can be valued, but not quantified) and quantitative criteria can be used in a structured decision-making process. The aim of the present application of MCDA is to present a logical means of collating both data and expert opinions on the best way to focus FFLC tests on endocrine active substances. The analyses are presented to demonstrate how MCDA can be used in this context. Each of 3 workgroups focused on 1 of 3 species: fathead minnow (Pimephales promelas), Japanese medaka (Oryzias latipes), and zebrafish (Danio rerio). Test endpoints (e.g., fecundity, growth, gonadal histopathology) were scored for each species for various desirable features such as statistical power and ecological relevance, with the importance of these features determined by assigning weights to them, using a swing weighting procedure. The endpoint F1 fertilization success consistently emerged as a preferred option for all species. In addition, some endpoints scored highly in particular species, such as development of secondary sexual characteristics (fathead minnow) and sex ratio (zebrafish). Other endpoints such as hatching success ranked relatively highly and should be considered as useful endpoints to measure in tests with any of the fish species. MCDA also indicated relatively less preferred endpoints in fish life cycle tests. For example, intensive histopathology consistently ranked low, as did measurement of diagnostic biomarkers, such as vitellogenin, most likely due to the high costs of these methods or their limited ecological relevance. Life cycle tests typically do not focus on identifying toxic modes and/or mechanisms of action, but rather, single chemical concentration-response relationships for endpoints (e.g., survival, growth, reproduction) that can be translated into evaluation of risk. It is, therefore, likely to be an inefficient use of limited resources to measure these mechanism-specific endpoints in life cycle tests, unless the value of such endpoints for answering particular questions justifies their integration in specific case studies.

Chemical amplification in an invaded food web: seasonality and ontogeny in a high-biomass, low-diversity ecosystem.

The global spread of invasive species is changing the structure of aquatic food webs worldwide. The North American Great Lakes have proved particularly vulnerable to this threat. In nearshore areas, invasive benthic species such as dreissenid mussels and round gobies (Neogobius melanostomus) have gained dominance in recent years. Such species are driving the flow of energy and material from the water column to the benthic zone, with dramatic effect on nutrient and contaminant cycling. Here, we develop a stage-structured model of a benthified food web in Lake Michigan with seasonal resolution and show how its bioaccumulation patterns differ from expected ones. Our model suggests that contaminant recycling through the consumption of lipid-rich fish eggs and mussel detritus is responsible for these differences. In southern Lake Michigan's Calumet Harbor (Chicago, IL, USA), round gobies have nitrogen isotope signatures with considerable spread, with some values higher than their predators and others lower than their prey. Contrary to patterns observed in linear pelagic systems, we predict that polychlorinated biphenyl (PCB) concentrations in these fish decrease with increasing size due to the lipid- and benthos-enriched diets of smaller fish. We also present here round goby PCB concentrations measured in 2005 after an invasional succession in Calumet Harbor and demonstrate how the change from one invasive mussel species to another may have led to a decrease in round goby PCB accumulation. Our results suggest that benthic-dominated systems differ from pelagic ones chiefly due to the influence of detritus and that these effects are exacerbated in systems with low species diversity and high biomass.

CSF neurofilaments in frontotemporal dementia compared with early onset Alzheimer's disease and controls.

BACKGROUND: Frontotemporal dementia (FTD) is pathologically heterogeneous, sometimes revealing intraneuronal inclusions of neurofilaments. We therefore measured CSF neurofilament profiles in patients with FTD, patients with early onset Alzheimer's disease (EAD) and healthy control subjects to explore the discriminative potential of CSF neurofilaments compared with the existing CSF biomarkers amyloid-beta(1-42), tau and tau phosphorylated at threonine-181. METHODS: CSF levels of light chain, heavy chain and hyperphosphorylated heavy chain neurofilaments (NfL, t-NfH and P-NfH) were compared between 17 subjects with FTD, 20 with EAD and 25 cognitively healthy controls. RESULTS: A subgroup of FTD patients had remarkably high CSF levels of both NfL and NfH. The degree of NfH phosphorylation was increased in FTD compared to both other groups. The levels of CSF NfL were significantly higher in EAD compared to controls. CONCLUSION: Differences in CSF biomarker profiles might reflect differential involvement of neurofilaments and tau in FTD and EAD. The subgroup of FTD patients with high CSF neurofilament levels may have a different neuropathological substrate and future studies addressing this specific issue are needed.