A hypomorphic variant of choroideremia is associated with a novel intronic mutation that leads to exon skipping.

INTRODUCTION: Molecular confirmation of pathogenic sequence variants in the CHM gene is required prior to enrolment in retinal gene therapy clinical trials for choroideremia. Individuals with mild choroideremia have been reported. The molecular basis of genotype-phenotype associations is of clinical relevance since it may impact on selection for retinal gene therapy. METHODS AND MATERIALS: Genetic testing and RNA analysis were undertaken in a patient with mild choroideremia to confirm the pathogenicity of a novel intronic variant in CHM and to explore the mechanism underlying the mild clinical phenotype. RESULTS: A 42-year-old male presented with visual field loss. Fundoscopy and autofluorescence imaging demonstrated mild choroideremia for his age. Genetic analysis revealed a variant at a splice acceptor site in the CHM gene (c.1350-3C > G). RNA analysis demonstrated two out-of-frame transcripts, suggesting pathogenicity, without any detectable wildtype transcripts. One of the two out-of-frame transcripts is present in very low levels in healthy controls. DISCUSSION: Mild choroideremia may result from +3 or -3 splice site variants in CHM. It is presumed that the resulting mRNA transcripts may be partly functional, thereby preventing the development of the null phenotype. Choroideremia patients with such variants may present challenges for gene therapy since there may be residual transcript activity which could result in long-lasting visual function which is atypical for this disease.

Hypomorphic CDHR1 variants may result in retinitis pigmentosa with relative preservation of cone function.

PURPOSE: Retinitis pigmentosa (RP) associated with biallelic variants in CDHR1 has rarely been reported, and detailed phenotyping data are not available. RP implies relative preservation of foveal cones, when compared to cone-rod dystrophy associated with biallelic null variants in CDHR1. We hypothesize that RP may occur in association with one or more hypomorphic CDHR1 alleles. MATERIALS AND METHODS: Retrospective report of a 48-year-old patient with CDHR1-associated RP with a hypomorphic missense variant c.562 G>A, p. (Gly188Ser) and a novel, unreported variant affecting a canonical splice acceptor site (c.784-1 G>C). Clinical examination, multimodal retinal imaging, electroretinography, visual field testing, and mesopic microperimetry were undertaken 8 years apart. Scotopic microperimetry was also performed. The DNA sequence context of the variants was examined to identify theoretical CRISPR-Cas9 base-editing strategies. RESULTS: The patient presented at 35 years with a 12-year history of nyctalopia. His best corrected visual acuity was 20/20. Clinical presentation, multimodal retinal imaging studies, electroretinography, and mesopic microperimetry were typical of a progressive rod-cone dystrophy (i.e. classic RP). There were no scotomas within the central field as would be expected at this age in CDHR1-associated cone-rod dystrophy. Scotopic microperimetry suggested some preservation of macular cone over rod function, although both were severely impaired. A suitable CRISPR adenine base editor was identified that could theoretically correct the missense variant c.562 G>A, p. (Gly188Ser). CONCLUSIONS: CDHR1-associated RP shows a relative preservation of cone function in the presence of a presumed hypomorphic allele and may be considered a hypomorphic disease phenotype. Further work is required to identify modifying factors that determine disease phenotype since macular dystrophy, with relative sparing of rods, may also occur with hypomorphic CDHR1 alleles.

Outcomes and Adverse Effects of Voretigene Neparvovec Treatment for Biallelic RPE65-Mediated Inherited Retinal Dystrophies in a Cohort of Patients from a Single Center.

Our study evaluated the morphological and functional outcomes, and the side effects, of voretigene neparvovec (VN) gene therapy for RPE65-mediated inherited retinal dystrophies (IRDs) in 12 eyes (six patients) at the Oxford Eye Hospital with a mean follow-up duration of 8.2 (range 1-12) months. All patients reported a subjective vision improvement 1 month after gene therapy. Best-corrected visual acuity (BCVA) remained stable (baseline: 1.28 (±0.71) vs. last follow-up: 1.46 (±0.60); p = 0.25). Average white Full-Field Stimulus Testing (FST) showed a trend towards improvement (baseline: -4.41 (±10.62) dB vs. last follow-up: -11.98 (±13.83) dB; p = 0.18). No changes in central retinal thickness or macular volume were observed. The side effects included mild intraocular inflammation (two eyes) and cataracts (four eyes). Retinal atrophy occurred in 10 eyes (eight mild, two severe) but did not impact FST measurements during the follow-up period. Increased intraocular pressure (IOP) was noted in three patients (six eyes); four eyes (two patients) required glaucoma surgery. The overall safety and effectiveness of VN treatment in our cohort align with previous VN clinical trials, except for the higher occurrence of retinal atrophy and increased IOP in our cohort. This suggests that raised IOP and retinal atrophy may be more common than previously reported.

Clinical Research on the Leading Causes of Severe Sight Impairment in the UK General and Working Populations.

Purpose: Clinical research brings the potential of improved diagnostics, sight-saving treatments, and more accessible services to those suffering with severe sight impairment (SSI). This report investigates whether registered ophthalmology clinical studies address the leading causes of SSI in the general and working populations of the United Kingdom (UK). Methods: The latest statistics on the leading causes of SSI in the UK general and working populations were identified by searching PubMed, Cochrane Library, and TRIP databases. Clinical study registries were searched to identify registered clinical studies (on or prior to 1st December 2022) on the leading causes of SSI. The relationship between the number of clinical studies on leading causes of SSI and the percentage of SSI certifications they account for was analyzed. Results: In the UK general population, the number of registered clinical studies on the leading causes of SSI is statistically significantly correlated (Spearman's rho = 0.86, p < 0.01) with the percentage of SSI certifications they account for. However, there is no correlation between the two in the UK working population (aged 16-64) (Spearman's rho = 0.15, p = 0.70). Eye conditions accounting for the most SSI certifications in individuals of working age have significantly less clinical research activity than those that cause the most SSI certifications in the general population. Out of the leading causes of SSI certifications studied, disorders of the visual cortex and congenital anomalies of the eye have the least clinical research activity. Conclusion: Clinical research into the leading causes of SSI in the general population is essential. However, it is important to consider eye conditions that cause the most severe visual impairment in individuals of working age due to the significant health and socioeconomic implications of sight loss in this population.

Choroideremia: The Endpoint Endgame.

Choroideremia is an X-linked retinal degeneration resulting from the progressive, centripetal loss of photoreceptors and choriocapillaris, secondary to the degeneration of the retinal pigment epithelium. Affected individuals present in late childhood or early teenage years with nyctalopia and progressive peripheral visual loss. Typically, by the fourth decade, the macula and fovea also degenerate, resulting in advanced sight loss. Currently, there are no approved treatments for this condition. Gene therapy offers the most promising therapeutic modality for halting or regressing functional loss. The aims of the current review are to highlight the lessons learnt from clinical trials in choroideremia, review endpoints, and propose a future strategy for clinical trials.

Correlation Between Fundus Autofluorescence Pattern and Retinal Function on Microperimetry in Choroideremia.

Purpose: In patients with choroideremia, it is not known how smooth and mottled patterns on short-wavelength fundus autofluorescence (AF) imaging relate to retinal function. Methods: A retrospective case-note review was undertaken on 190 patients with choroideremia at two specialist centers for retinal genetics. Twenty patients with both smooth and mottled zones on short-wavelength AF imaging and concurrent mesopic microperimetry assessments were included. Mean retinal sensitivities within the smooth and mottled zones were compared between choroideremia patients, and identical points on mesopic microperimetry collected from 12 age-matched controls. Longitudinal analyses were undertaken at 2 and 5 years in a subset of patients. Results: In patients with choroideremia, mean retinal sensitivities at baseline were significantly greater in the smooth zone (26.1 ± 2.0 dB) versus the mottled zone (20.5 ± 4.2 dB) (P < 0.0001). Mean retinal sensitivities at baseline were similar in the smooth zone between choroideremia patients and controls (P = 0.054) but significantly impaired in the mottled zone in choroideremia compared to controls (P < 0.0001). The rate of decline in total sensitivity over 5 years was not significant in either the smooth or mottled zone in a small subset of choroideremia patients (n = 7; P = 0.344). Conclusions: In choroideremia, retinal sensitivity as determined by microperimetry correlates with patterns on AF imaging: retinal function in the smooth zone, where the retinal pigment epithelium is anatomically preserved, is similar to controls, but retinal sensitivity in the mottled zone is impaired. Translational Relevance: Patterns on AF imaging may represent a novel, objective outcome measure for clinical trials in choroideremia as a surrogate for retinal function.

Microperimetry as an Outcome Measure in RPGR-associated Retinitis Pigmentosa Clinical Trials.

Purpose: To explore which microperimetry sensitivity index (pointwise sensitivity, mean sensitivity, and volume sensitivity) is suitable as a microperimetry outcome measure in patients with X-linked RPGR-associated retinitis pigmentosa (RP). Methods: Microperimetry data from patients with RPGR-associated RP were collected and analyzed retrospectively. Fourteen participants completed triplicate microperimetry testing, across 2 consecutive days for the repeatability analyses. Longitudinal data was obtained from 13 participants who completed microperimetry testing at two separate visits. Results: The test-retest coefficients of repeatability (CoR) for pointwise sensitivity were ±9.5 dB and ±9.3 dB, in the right and left eyes, respectively. The mean sensitivity CoR for the right and left eyes was ±0.7 dB and ±1.3 dB. Volume sensitivity CoR was ±144.5 dB*deg2 and ±324.2 dB*deg2 for the right and left eyes, respectively. The mean sensitivities were positively skewed toward zero in those with a high number of nonseeing points (arbitrarily assigned to -1.0 dB) and just seen points (0.0 dB). Volume sensitivities were unaffected by the averaging effects of skewed data. Conclusions: Clinical trials should report population-specific test-retest variability to determine a clinically significant change. Pointwise sensitivity indices should be used with caution as outcome measures in clinical trials owing to high levels of test-retest variability. Global indices seem to be less prone to variability. Volume sensitivity indices seem to be superior for use in RPGR-associated RP clinical trials compared with mean sensitivity because they are unaffected by the averaging effects of highly skewed data. Translational Relevance: Careful selection of sensitivity indices (VA) is required when using microperimetry as a clinical trial outcome measure.

Development, growth and metabolic effects in stage IV lobster (Homarus americanus) following chronic exposure to sediments spiked with commercial formulations of deltamethrin and permethrin.

Coastal and estuarine ecosystems are environments heavily influenced by natural and anthropogenic activities. Chemicals used for pest control in agriculture and aquaculture may accumulate in natural coastal environments. Pyrethroids are common pesticides that are used on crops as well as applied to aquaculture pens and then may disperse in the surrounding ocean once treatment is complete. This study observed the sublethal effects of two pyrethroids, permethrin and deltamethrin (within commercially available formulations), on post-larval stage IV American lobster (Homarus americanus) using growth parameters and metabolic rate as indicators. Observed effects on growth parameters were a decrease in size increment and specific growth rate as well as an increase in intermolt period in stage IV lobsters exposed to 100 µg/kg permethrin. No significant differences were found for intermolt period, size increment, or specific growth rate in deltamethrin-exposed stage IV lobsters. Metabolic rates were not significantly different between deltamethrin-exposed and control lobsters, however, this sublethal effect warrants further investigation. Collectively, these results represent the first examination of the sublethal effects of exposure to pyrethroids formulations in post-larval lobsters, highlighting the potential for effects on non-target marine organisms.

Microperimetry Reliability Assessed From Fixation Performance.

Purpose: Microperimetry provides an accurate assessment of central retinal sensitivity due to its fundus-tracking capability, but it has limited reliability indicators. One method currently employed, fixation loss, samples the optic nerve blind spot for positive responses; however, it is unclear if these responses arise from unintentional button presses or from tracking failure leading to stimuli misplacement. We investigated the relationship between blind spot scotoma positive responses (termed scotoma responses) and fixation. Methods: Part 1 of the study involved a custom grid of 181 points centered on the optic nerve that was constructed to map physiological blind spots in primary and simulated eccentric fixation positions. Scotoma responses and the 63% and 95% fixation bivariate contour ellipse areas (BCEA63 and BCEA95) were analyzed. In Part 2, fixation data from controls and patients with retinal diseases (234 eyes from 118 patients) were collected. Results: Part 1, a linear mixed model of 32 control participants, demonstrated significant (P < 0.001) correlation between scotoma responses and BCEA95. In Part 2, the upper 95% confidence intervals for BCEA95 were 3.7 deg2 for controls, 27.6 deg2 for choroideremia, 23.1 deg2 for typical rod-cone dystrophies, 21.4 deg2 for Stargardt disease, and 111.3 deg2 for age-related macular degeneration. Incorporating all pathology groups into an overall statistic resulted in an upper limit BCEA95 = 29.6 deg2. Conclusions: Microperimetry reliability is significantly correlated to fixation performance, and BCEA95 provides a surrogate marker for test accuracy. Examinations of healthy individuals and patients with retinal disease are deemed unreliable if BCEA95 > 4 deg2 and BCEA95 > 30 deg2, respectively. Translational Relevance: Microperimetry reliability should be assessed using fixation performance as summarized by BCEA95 rather than the level of fixation losses.

A cross-sectional study to assess the clinical utility of modern visual function assessments in patients with inherited retinal disease: a mixed methods observational study protocol.

BACKGROUND: Treatment options for patients with inherited retinal disease are limited, although research into novel therapies is underway. To ensure the success of future clinical trials, appropriate visual function outcome measures that can assess changes resulting from therapeutic interventions are urgently required. Rod-cone degenerations are the most common type of inherited retinal disease. Visual acuity is a standard measure but is typically preserved until late disease stages, frequently making it an unsuitable visual function marker. Alternative measures are required. This study investigates the clinical utility of a range of carefully selected visual function tests and patient reported outcome measures. The aim is to identify suitable outcome measures for future clinical trials that could be considered for regulatory approval. METHODS: This cross-sectional study involves two participant groups, patients with inherited retinal disease (n = 40) and healthy controls (n = 40). The study has been designed to be flexible and run alongside NHS clinics. The study is split into two parts. Part one includes examining standard visual acuity, low luminance visual acuity, the Moorfields acuity chart visual acuity, mesopic microperimetry and three separate patient reported outcome measures. Part two involves 20 min of dark adaptation followed by two-colour scotopic microperimetry. Repeat testing will be undertaken where possible to enable repeatability analyses. A subset of patients with inherited retinal disease will be invited to participate in a semi-structured interview to gain awareness of participants' thoughts and feelings around the study and different study tests. DISCUSSION: The study highlights a need for reliable and sensitive validated visual function measures that can be used in future clinical trials. This work will build on work from other studies and be used to inform an outcome measure framework for rod-cone degenerations. The study is in keeping with the United Kingdom Department of Health and Social Care research initiatives and strategies for increasing research opportunities for NHS patients as part of their NHS care. TRIAL REGISTRATION: ISRCTN registry, ISRCTN24016133, Visual Function in Retinal Degeneration, registered on 18th August 2022.

Is RPGR-related retinal dystrophy associated with systemic disease? A case series.

BACKGROUND: Ciliopathies responsible for retinitis pigmentosa can also cause systemic manifestations. RPGR is a ciliary gene and pathogenic variants in RPGR cause a retinal ciliopathy, the commonest cause of X-linked recessive retinitis pigmentosa. The RPGR protein interacts with numerous other ciliary proteins present in the transition zone of both motile and sensory cilia, and may play an important role in regulating ciliary protein transport. There has been a growing, putative association of RPGR variants with systemic ciliopathies: mainly sino-respiratory infections and primary ciliary dyskinesia. MATERIALS AND METHODS: Retrospective case series of patients with RPGR-RP presenting to Oxford Eye Hospital with systemic disease. RESULTS: We report three children with RPGR-related rod-cone dystrophy, all of whom have mutations in the N-terminus of RPGR. Two cases co-presented with confirmed diagnoses of primary ciliary dyskinesia and one case with multiple sino-respiratory symptoms strongly suggestive of primary ciliary dyskinesia. These and all previously reported RPGR co-pathologies relate to ciliopathies and have no other systemic associations. CONCLUSIONS: The link between RPGR variants and a systemic ciliopathy remains plausible, but currently unproven.

Harnessing the potential of practice-based clinical optometry research in the United Kingdom.

Research is the core of evidence-based practice across all healthcare, in order to ensure optimum patient care. The College of Optometrists is a national standard setting institution for optometric practice in the United Kingdom. However, the standards are only as good as the available evidence, and currently there is little evidence relating directly to optometric practice. The National Institute of Health and Care Research, the General Medical Council and The College of Optometrists, amongst others, have published research strategies describing ambitious plans to expand the scope of healthcare research. The aim of this article is to raise awareness of these government initiatives and consider how they may relate to optometric practice. To improve optometrist research engagement, we need to address the barriers to research and implement strategies to overcome them. There are many opportunities to support research, with different degrees of involvement, from signposting patients to research studies, supporting recruitment or collecting data for a multicentre clinical trial, as well as undertaking an individual research project. Healthcare research is changing and there is scope for more practice-based research activities in optometry. Research should not be a solo endeavour but a multi-disciplinary effort. Greater collaborations across all stakeholders, including primary care, secondary care, academia, regulators and industry is needed to make this possible.

Wheat EARLY FLOWERING 3 affects heading date without disrupting circadian oscillations.

Plant breeders have indirectly selected for variation at circadian-associated loci in many of the world's major crops, when breeding to increase yield and improve crop performance. Using an eight-parent Multiparent Advanced Generation Inter-Cross (MAGIC) population, we investigated how variation in circadian clock-associated genes contributes to the regulation of heading date in UK and European winter wheat (Triticum aestivum) varieties. We identified homoeologues of EARLY FLOWERING 3 (ELF3) as candidates for the Earliness per se (Eps) D1 and B1 loci under field conditions. We then confirmed a single-nucleotide polymorphism within the coding region of TaELF3-B1 as a candidate polymorphism underlying the Eps-B1 locus. We found that a reported deletion at the Eps-D1 locus encompassing TaELF3-D1 is, instead, an allele that lies within an introgression region containing an inversion relative to the Chinese Spring D genome. Using Triticum turgidum cv. Kronos carrying loss-of-function alleles of TtELF3, we showed that ELF3 regulates heading, with loss of a single ELF3 homoeologue sufficient to alter heading date. These studies demonstrated that ELF3 forms part of the circadian oscillator; however, the loss of all homoeologues was required to affect circadian rhythms. Similarly, loss of functional LUX ARRHYTHMO (LUX) in T. aestivum, an orthologue of a protein partner of Arabidopsis (Arabidopsis thaliana) ELF3, severely disrupted circadian rhythms. ELF3 and LUX transcripts are not co-expressed at dusk, suggesting that the structure of the wheat circadian oscillator might differ from that of Arabidopsis. Our demonstration that alterations to ELF3 homoeologues can affect heading date separately from effects on the circadian oscillator suggests a role for ELF3 in cereal photoperiodic responses that could be selected for without pleiotropic deleterious alterations to circadian rhythms.

Adaptive stimulation of macropinocytosis overcomes aspartate limitation in cancer cells under hypoxia.

Stress-adaptive mechanisms enable tumour cells to overcome metabolic constraints under nutrient and oxygen shortage. Aspartate is an endogenous metabolic limitation under hypoxic conditions, but the nature of the adaptive mechanisms that contribute to aspartate availability and hypoxic tumour growth are poorly understood. Here we identify GOT2-catalysed mitochondrial aspartate synthesis as an essential metabolic dependency for the proliferation of pancreatic tumour cells under hypoxic culture conditions. In contrast, GOT2-catalysed aspartate synthesis is dispensable for pancreatic tumour formation in vivo. The dependence of pancreatic tumour cells on aspartate synthesis is bypassed in part by a hypoxia-induced potentiation of extracellular protein scavenging via macropinocytosis. This effect is mutant KRAS dependent, and is mediated by hypoxia-inducible factor 1 (HIF1A) and its canonical target carbonic anhydrase-9 (CA9). Our findings reveal high plasticity of aspartate metabolism and define an adaptive regulatory role for macropinocytosis by which mutant KRAS tumours can overcome nutrient deprivation under hypoxic conditions.

Characterizing Visual Fields in RPGR Related Retinitis Pigmentosa Using Octopus Static-Automated Perimetry.

Purpose: Peripheral visual fields have not been as well defined by static automated perimetry as kinetic perimetry in RPGR-related retinitis pigmentosa. This study explores the pattern and sensitivities of peripheral visual fields, which may provide an important end point when assessing interventional clinical trials. Methods: A retrospective observational cross-sectional study of 10 genetically confirmed RPGR subjects was performed. Visual fields were obtained using the Octopus 900 perimeter. Interocular symmetry and repeatability were quantified. Visual fields were subdivided into central and peripheral subfields for analysis. Results: Mean patient age was 32 years old (20 to 49 years old). Average mean sensitivity was 7 dB (SD = 3.67 dB) and 6.8 dB (SD = 3.4 dB) for the right and left eyes, respectively, demonstrating interocular symmetry. Coefficient of repeatability for overall mean sensitivity: <2 dB. Nine out of 10 subjects had a preserved inferotemporal subfield, whose mean sensitivity was highly correlated to the central field (r2 = 0.78, P = 0.002 and r2 = 0.72, P = 0.002 for the right and left eyes, respectively). Within the central field, sensitivities were greater in the temporal than the nasal half (t-test, P = 0.01 and P = 0.03 for the right and left eyes, respectively). Conclusions: Octopus static-automated perimeter demonstrates good repeatability. Interocular symmetry permits use of the noninterventional eye as an internal control. In this cohort, the inferotemporal and central visual fields are preserved into later disease stages likely mapping to populations of surviving cones. Translational Relevance: A consistently preserved inferotemporal island of vision highly correlated to that of the central visual field may have significance as a possible future therapeutic site.

Scotopic microperimetry: evolution, applications and future directions.

For many inherited and acquired retinal diseases, reduced night vision is a primary symptom. Despite this, the clinical testing options for spatially resolved scotopic vision have until recently been limited. Scotopic microperimetry is a relatively new visual function test that combines two-colour perimetry with fundus-controlled perimetry performed in scotopic luminance conditions. The technique enables spatially resolved mapping of central retinal sensitivity alongside the ability to distinguish between rod and cone photoreceptor sensitivities. Two companies produce commercially available scotopic microperimeters - Nidek (Nidek Technologies Srl, Padova, Italy) and CenterVue (CenterVue S.p.A., Padova, Italy). Scotopic microperimetry is a promising technology capable of detecting changes in retinal sensitivity before changes in other measures of visual function. Scotopic microperimetry is a promising functional biomarker that has the potential as a useful clinical trial outcome measure. This review summarises the evolution and applications of scotopic microperimetry, and discusses testing options, including testing grid selection, dark-adaptation time and threshold sensitivity analyses.

From Activated Partial Thromboplastin Time to Antifactor Xa and Back Again.

OBJECTIVES: Monitoring is essential to safe anticoagulation prescribing and requires close collaboration among pathologists, clinicians, and pharmacists. METHODS: We describe our experience in the evolving strategy for laboratory testing of unfractionated heparin (UFH). RESULTS: An intrainstitutional investigation revealed significant discordance between activated partial thromboplastin time (aPTT) and antifactor Xa (anti-Xa) assays, prompting a transition from the former to the latter in 2013. With the increasing use of oral factor Xa inhibitors (eg, apixaban, rivaroxaban, edoxaban, betrixaban), which interfere with the anti-Xa assay, we adapted our protocol again to incorporate aPTT in patients admitted on oral Xa inhibitors who require transition to UFH. CONCLUSIONS: Our experience demonstrates key challenges in anticoagulation and highlights the importance of clinical pathologists in helping health systems adapt to the changing anticoagulation landscape.

Exposure of American lobster (Homarus americanus) to the pesticide chlorpyrifos results in changes in gene expression.

Chlorpyrifos is an organophosphate that is currently used to reduce arthropod pests for the protection of agricultural crops. Coastal marine ecosystems may be exposed to agricultural pesticides via runoff and pesticide exposure can impact the health and survival of non-target species such as the American lobster (Homarus americanus). In the current study, the gene expression changes of H. americanus stage IV larvae were evaluated to understand the physiological mechanisms affected by exposure to sublethal concentrations of chlorpyrifos. After 48 h chlorpyrifos exposure, surviving lobsters were processed for Illumina RNA sequencing (RNA-seq). Genes of interest that showed significant changes using RNA-seq were verified using reverse transcriptase quantitative polymerase chain reaction (RT-qPCR). Analysis of RNA-seq and the confirmation of gene expression patterns via RT-qPCR found altered expression in genes related to stress response (glutathione peroxidase 3 and heat shock protein 60), hypoxia response (hairy, astakine 2, hemocyanin), moulting (cytochrome P450 307a1 and chitinase), and immunity (astakine 2) pathways. Changes to gene expression were most notable in lobsters exposed to 0.57 µg/L chlorpyrifos.

Current Practice and Clinical Utility of Thrombophilia Testing in Hospitalized Patients with Acute Ischemic Stroke.

BACKGROUND AND PURPOSE: Testing for thrombophilic disorders is often performed in patients after cryptogenic ischemic stroke in an attempt to identify a hematologic explanation for the event. However, the role of commonly tested thrombophilias in ischemic stroke is poorly defined. There is limited evidence to quantify how these disorders affect ischemic stroke risk and testing practices are highly variable. METHODS: Retrospective evaluation of thrombophilia testing practices and clinical outcomes was performed in hospitalized patients with acute ischemic stroke (n = 1898) at a large academic hospital over a two-year period. Variables assessed included testing components, timing of testing, number of abnormal results, and frequency of change in clinical management prompted by abnormal results. A provider survey was also performed to assess perceptions of current testing practices and provider understanding of testing indications. RESULTS: Thrombophilia testing was performed in 190 (10%) patients admitted for acute ischemic stroke. Of those tested, 137 (72.1%) had at least one abnormal result, but this decreased to 37.4% when elevated factor VIII activity was excluded. An abnormal result prompted initiation of anticoagulation in only 4 patients (2%). The provider survey indicated that all providers (100%) were selecting thrombophilia tests using a pre-existing order set and were interested in additional education on testing indications and interpretation. Comparison to similar studies at other institutions revealed significant variation in testing practices, and a small proportion of patients in which testing prompted a change in management (1-8%). CONCLUSIONS: Thrombophilia testing is frequently obtained in hospitalized patients with acute ischemic stroke, yet testing only changed management in 2% of patients. Efforts to improve provider education and the stewardship of testing are needed to ensure appropriate evaluation and treatment of patients with acute ischemic stroke.

Effects of Sublethal Chlorpyrifos Exposure on Postlarval American Lobster (Homarus americanus).

The organophosphate pesticide chlorpyrifos has been introduced to the marine environment via adsorption to agricultural soil runoff or as spray drift. Chlorpyrifos affects the survival of some larval decapod crustaceans, but no data exist on the impacts to the American lobster, Homarus americanus. The purpose of the present study was to assess the levels at which chlorpyrifos affects the survival of postlarval H. americanus. Using acute saltwater exposures, the 24- and 48-h median lethal concentrations were established for stage IV H. americanus (1.56 and 1.33 µg/L, respectively). Movement, acetylcholinesterase activity, intermoult period, specific growth rate, and moult increment were measured during exposure to sublethal concentrations. Movement patterns were assessed to establish a 48-h median inhibition concentration for cessation of normal movement (0.66 µg/L). Acetylcholinesterase activity was found to be inhibited immediately post-exposure to 0.50, 0.57, and 0.82 µg/L chlorpyrifos but could be recovered within a period (9-15 d) in clean seawater. Sublethal growth effects of increased intermoult period, decreased specific growth rate, and decreased moult increment were observed during exposure to an environmentally relevant concentration (0.82 µg/L). The present study suggests that H. americanus stage IV larvae were marginally less sensitive to chlorpyrifos compared with other decapods and that acute lethality of H. americanus postlarvae is not likely to occur with chlorpyrifos concentrations previously reported from aquatic environments. Environ Toxicol Chem 2019;38:1294-1301. © 2019 SETAC.