Global cross-cultural validation of a brief measure for identifying potential suicide risk in 42 countries

OBJECTIVES

This study aimed to examine the psychometric properties of the P4 suicide screener in a multinational sample. The primary goal was to evaluate the reliability and validity of the scale and investigate its convergent validity by analyzing its correlation with depression, anxiety, and substance use.

STUDY DESIGN

The study design is a cross-sectional self-report study conducted across 42 countries.

METHODS

A cross-sectional, self-report study was conducted in 42 countries, with a total of 82,243 participants included in the final data set.

RESULTS

The study provides an overview of suicide ideation rates across 42 countries and confirms the structural validity of the P4 screener. The findings indicated that sexual and gender minority individuals exhibited higher rates of suicidal ideation. The P4 screener showed adequate reliability, convergence, and discriminant validity, and a cutoff score of 1 is recommended to identify individuals at risk of suicidal behavior.

CONCLUSIONS

The study supports the reliability and validity of the P4 suicide screener across 42 diverse countries, highlighting the importance of using a cross-cultural suicide risk assessment to standardize the identification of high-risk individuals and tailoring culturally sensitive suicide prevention strategies.

The effects of gastrojejunostomy tube placement on pulmonary and gastrointestinal complications following spinal fusion for neuromuscular scoliosis

To evaluate whether preoperative conversion from a gastrostomy tube (G-tube) to a gastrojejunostomy tube (GJ-tube) decreases short-term postoperative aspiration pneumonia and gastrointestinal complications in children with neuromuscular scoliosis. We conducted a retrospective chart review from January 2006 to October 2021 of pediatric patients who had neuromuscular scoliosis and were fed with a G-tube before spinal fusion. Eligible patients were divided into two groups based on whether they were converted to a GJ-tube preoperatively. Preoperative characteristics and 30-day postoperative outcomes were compared between groups using Chi-square tests. Of 261 eligible patients, 205 were converted to a GJ-tube, while 56 underwent spinal fusion with a G-tube. Common complications following G-tube to GJ-tube conversion were feeding intolerance (25.2%), GJ-tube malfunction (17.7%), and at least one episode of vomiting (17.4%). Within 30 days of discharge, 12.5% of GJ-tube patients and 11.5% of G-tube patients experienced aspiration pneumonia (P = 0.85). The GJ-tube group received postoperative tube feeds 7 hours earlier than the G-tube group on average (51.6 h vs. 44.5 h, P = 0.02). Within 30 days of discharge, one (0.5%) patient from the GJ-tube group died of gastrointestinal complications unrelated to conversion and two (3.6%) patients in the G-tube group died from aspiration pneumonia (P = 0.12). Results suggest that there were no appreciable differences in outcomes between patients converted to a GJ-tube preoperatively compared to those who continued to use a G-tube. However, preoperative characteristics indicate that a higher number of complex patients were converted to a GJ-tube, indicating potential selection bias in this retrospective sample. Level of evidence: Level III.

Unifying the Conversation: Membrane Separation Performance in Energy, Water, and Industrial Applications

Dense polymer membranes enable a diverse range of separations and clean energy technologies, including gas separation, water treatment, and renewable fuel production or conversion. The transport of small molecular and ionic solutes in the majority of these membranes is described by the same solution-diffusion mechanism, yet a comparison of membrane separation performance across applications is rare. A better understanding of how structure-property relationships and driving forces compare among applications would drive innovation in membrane development by identifying opportunities for cross-disciplinary knowledge transfer. Here, we aim to inspire such cross-pollination by evaluating the selectivity and electrochemical driving forces for 29 separations across nine different applications using a common framework grounded in the physicochemical characteristics of the permeating and rejected solutes. Our analysis shows that highly selective membranes usually exhibit high solute rejection, rather than fast solute permeation, and often exploit contrasts in the size and charge of solutes rather than a nonelectrostatic chemical property, polarizability. We also highlight the power of selective driving forces (e.g., the fact that applied electric potential acts on charged solutes but not on neutral ones) to enable effective separation processes, even when the membrane itself has poor selectivity. We conclude by proposing several research opportunities that are likely to impact multiple areas of membrane science. The high-level perspective of membrane separation across fields presented herein aims to promote cross-pollination and innovation by enabling comparisons of solute transport and driving forces among membrane separation applications.

New-onset as opposed to established atrial fibrillation as a risk factor for incident stroke

BACKGROUND

Atrial fibrillation (AF) is an established risk factor for acute ischemic stroke (AIS). It remains unclear if new-onset AF confers a higher risk of AIS than longer-standing AF.

METHODS

We retrospectively analyzed all stroke-free patients who underwent transthoracic echocardiography (TTE) in the Henry Ford Health System between March 6 and September 6, 2016. Incident AIS and new-onset AF were ascertained by the presence of new diagnostic codes in the electronic medical record over a follow-up period of up to 5 years. Cox proportional hazards regression was used to identify risk factors for new-onset AF or AIS.

RESULTS

Of 7310 patients who underwent baseline TTE the mean age was 65 years, 54% were female, 51% were Caucasian, and 46% had left atrial enlargement (LAE). Of at-risk patients, 10.9% developed new-onset AF and 2.9% experienced incident AIS. The risk of new-onset AF among at-risk patients was 3.1 times higher among patients with any degree of LAE compared to those with normal LA size (95% CI 2.6-3.6, P < 0.0001). New-onset AF, more than established AF, in turn had a powerful association with incident AIS. The cumulative 5-year risk of AIS was 3.5% in those without AF, 5.9% in those with established AF prior to TTE, and 20.1% in those with new-onset AF (P < 0.0001). In multivariable analysis new-onset AF had the strongest association with incident AIS (P < 0.0001), followed by increasing age (P = 0.0025), black race (P = 0.0032), and smoking (P = 0.0063).

CONCLUSIONS

New-onset AF has a strong relationship with incident AIS. LAE was present in nearly half of stroke-free patients undergoing TTE, and was associated with a significantly higher likelihood of new-onset AF during follow-up. Vigilant cardiac monitoring for AF in individuals with LAE, coupled with the timely initiation of anticoagulation, may be an important strategy for the primary prevention of AF-related stroke.

Consensus-Based Best Practice Guidelines for the Management of Spinal Deformity and Associated Tumors in Pediatric Neurofibromatosis Type 1: Screening and Surveillance, Surgical Intervention, and Medical Therapy

BACKGROUND

Spinal conditions, such as scoliosis and spinal tumors, are prevalent in neurofibromatosis type 1 (NF1). Despite the recognized importance of their early detection and treatment, there remain knowledge gaps in how to approach these manifestations. The purpose of this study was to utilize the experience of a multidisciplinary committee of experts to establish consensus-based best practice guidelines (BPGs) for spinal screening and surveillance, surgical intervention, and medical therapy in pediatric patients with NF1.

METHODS

Using the results of a prior systematic review, 10 key questions that required further assessment were first identified. A committee of 20 experts across medical specialties was then chosen based on their clinical experience with spinal deformity and tumors in NF1. These were 9 orthopaedic surgeons, 4 neuro-oncologists/oncologists, 3 neurosurgeons, 2 neurologists, 1 pulmonologist, and 1 clinical geneticist. An initial online survey on current practices and opinions was conducted, followed by 2 additional surveys via a formal consensus-based modified Delphi method. The final survey involved voting on agreement or disagreement with 35 recommendations. Items reaching consensus (≥70% agreement or disagreement) were included in the final BPGs.

RESULTS

Consensus was reached for 30 total recommendations on the management of spinal deformity and tumors in NF1. These were 11 recommendations on screening and surveillance, 16 on surgical intervention, and 3 on medical therapy. Five recommendations did not achieve consensus and were excluded from the BPGs.

CONCLUSION

We present a set of consensus-based BPGs comprised of 30 recommendations for spinal screening and surveillance, surgical intervention, and medical therapy in pediatric NF1.

Policies, Practices, and Attitudes Related to Parental Leave for Practicing Pediatric Orthopaedic Surgeons

BACKGROUND

Parental leave impacts family engagement, bonding, stress, and happiness. Because parental leave benefits are important to all surgeons regardless of sex, understanding parental leave practices in pediatric orthopaedic surgery is critical to promote equity within the profession and supporting balance in work and family life. The aim of this study was to survey pediatric orthopaedic surgeons about their knowledge of parental leave policies, attitudes towards parental leave, and their individual experiences taking leave.

METHODS

A 34-question anonymous survey was distributed to the Pediatric Orthopaedic Society of North America membership. Eligible respondents were attending pediatric orthopaedic surgeons practicing in the United States or Canada. The survey gathered information about employer parental leave policies, perceptions about and experiences with parental leave while practicing as a surgeon, and demographic information about respondents.

RESULTS

A total of 77 responses were completed and used for analysis. Most respondents were men (59.7%), <50 years old (67.5%), married (90.9%), and in urban communities (75.3%). A large majority were practicing in the United States (97.4%). Most respondents were unfamiliar with employer parental leave policies (maternity: 53.3%; paternity: 67.5%; and adoption: 85.7%). Those familiar with policies reported that employers offered 7 to 12 weeks for maternity leave (45.7%) and <1 week for paternity leave (50%) and adoption leave (45.5%). Most respondents believed 7 to 12 weeks should be offered for maternity leave (66.2%), 1 to 6 weeks for paternity leave (54.6%), and 7 to 12 weeks for adoption leave (46.8%). Many respondents reported taking 1 to 6 weeks of parental leave as a surgeon (53.3%) and that their colleagues were supportive of their parental leave (40.3%).

CONCLUSIONS

Most pediatric orthopaedic surgeons were unfamiliar with parental leave benefits provided by employers. Respondents who were familiar with these policies believed that more parental leave should be provided, especially for men who may feel social pressure to take less time for leave. Although respondents reported that their work environments were supportive, this study identified opportunities for improvement to support surgeons who wish to balance parental experiences with work responsibilities.

LEVEL OF EVIDENCE

Level V.

Gravity complexes as a focus of seafloor fluid seepage: the Rio Grande Cone, SE Brazil

Seafloor methane emissions can affect Earth's climate and ocean chemistry. Vast quantities of methane formed by microbial decomposition of organic matter are locked within gas hydrate and free gas on continental slopes, particularly in large areas with high sediment accumulations such as deep-sea fans. The release of methane in slope environments has frequently been associated with dissociation of gas hydrates near the edge of the gas hydrate stability zone on the upper slope, with discharges in greater water depths less understood. Here we show, using data from the Rio Grande Cone (western South Atlantic), that the intrinsic, gravity-induced downslope collapse of thick slope sediment accumulations creates structures that serve as pathways for gas migration, unlocking methane and causing seafloor emissions via giant gas flares in the water column. The observed emissions in the study region (up to 310 Mg year^-1) are three times greater than estimates for the entire US North Atlantic margin and reveal the importance of collapsing sediment accumulations for ocean carbon cycling. Similar outgassing systems on the Amazon and Niger fans suggest that gravity tectonics on passive margins is a common yet overlooked mechanism driving massive seafloor methane emissions in sediment-laden continental slopes.

The influence of viral respiratory season on perioperative outcomes in patients undergoing spinal fusion for neuromuscular scoliosis

PURPOSE

Respiratory complications are common following neuromuscular scoliosis (NMS) spinal fusion. Concern exists regarding the safety to perform complicated procedures in winter months when viral respiratory illness is common. The purpose of this study was to compare perioperative outcomes in children with NMS undergoing spinal fusion during peak (November-March) or non-peak (April-October) viral season.

METHODS

The Health Care and Utilization Project (HCUP) Kids' inpatient database (KID) from 2006 to 2012 was reviewed. Children 20 years or younger who underwent spinal fusion for NMS were included. Patients were grouped by date of surgery during peak or non-peak viral season. Continuous variables were compared using t tests and categorical variables were compared using the Rao-Scott Chi-square test. Weighted logistic regression models were performed.

RESULTS

This study identified 5082 records, including 1711 and 3371 patients who had surgery in peak and non-peak viral seasons, respectively. Patients who had spinal fusion during peak viral season were less likely to experience respiratory failure (p = 0.0008) and did not demonstrate an increased incidence of aspiration pneumonia (p = 0.26), respiratory complication (p = 0.43), or mortality (p = 0.68). Respiratory failure was associated with younger age (p = 0.0031), the presence of a tracheostomy (p < 0.0001), and the number of chronic conditions (p < 0.0001). Higher number of chronic medical conditions (mean of 5.0) was associated with an increased risk of in-hospital mortality (p < 0.0001), aspiration pneumonia (p = 0.0009), and respiratory failure (p < 0.0001).

CONCLUSION

Spinal fusion for NMS during peak viral season has a lower risk of respiratory failure without an increase in mortality or other complications compared to during non-peak viral season.

Mechanical Thrombectomy for Acute Ischemic Stroke in Metastatic Cancer Patients: A Nationwide Cross-Sectional Analysis

BACKGROUND AND PURPOSE

Mechanical thrombectomy (MT) is the standard treatment for large vessel occlusion (LVO) acute ischemic stroke. Patients with active malignancy have an increased risk of stroke but were excluded from MT trials.

METHODS

We searched the National Readmission Database for LVO patients treated with MT between 2016-2018 and compared the characteristics and outcomes of cancer-free patients to those with metastatic cancer (MC). Primary outcomes were all-cause in-hospital mortality and favorable outcome, defined as a routine discharge to home (regardless of whether home services were provided or not). Multivariate regression was used to adjust for confounders.

RESULTS

Of 40,537 LVO patients treated with MT, 933 (2.3%) had MC diagnosis. Compared to cancer-free patients, MC patients were similar in age and stroke severity but had greater overall disease severity. Hospital complications that occurred more frequently in MC included pneumonia, sepsis, acute coronary syndrome, deep vein thrombosis, and pulmonary embolism (P<0.001). Patients with MC had similar rates of intracerebral hemorrhage (20% vs. 21%) but were less likely to receive tissue plasminogen activator (13% vs. 23%, P<0.001). In unadjusted analysis, MC patients as compared to cancer-free patients had a higher in-hospital mortality rate and were less likely to be discharged to home (36% vs. 42%, P=0.014). On multivariate regression adjusting for confounders, mortality was the only outcome that was significantly higher in the MC group than in the cancerfree group (P<0.001).

CONCLUSION

LVO patients with MC have higher mortality and more infectious and thrombotic complications than cancer-free patients. MT nonetheless can result in survival with good outcome in slightly over one-third of patients.

Anion-exchange membranes with internal microchannels for water control in CO2 electrolysis

Electrochemical reduction of carbon dioxide (CO2R) poses substantial promise to convert abundant feedstocks (water and CO2) to value-added chemicals and fuels using solely renewable energy. However, recent membrane-electrode assembly (MEA) devices that have been demonstrated to achieve high rates of CO2R are limited by water management within the cell, due to both consumption of water by the CO2R reaction and electro-osmotic fluxes that transport water from the cathode to the anode. Additionally, crossover of potassium (K+) ions poses concern at high current densities where saturation and precipitation of the salt ions can degrade cell performance. Herein, a device architecture incorporating an anion-exchange membrane (AEM) with internal water channels to mitigate MEA dehydration is proposed and demonstrated. A macroscale, two-dimensional continuum model is used to assess water fluxes and local water content within the modified MEA, as well as to determine the optimal channel geometry and composition. The modified AEMs are then fabricated and tested experimentally, demonstrating that the internal channels can both reduce K+ cation crossover as well as improve AEM conductivity and therefore overall cell performance. This work demonstrates the promise of these materials, and operando water-management strategies in general, in handling some of the major hurdles in the development of MEA devices for CO2R.

Tribute to E. J. Capaldi: Celebration of a Psychological Scientist

E. J. (John) Capaldi (1928–2020) made numerous contributions to experimental psychology in his long career at the University of Texas at Austin and Purdue University. He was a pioneer in the area of animal learning and cognition, known for his sequential theory of partial reinforcement extinction effects. His research in this area and in memory and counting phenomena was conducted for the most part with rats running in straight alley mazes under various sequences of trial outcomes (e.g., reward, nonreward, variations in reward size). John's other interests included the sequential theory applied to Pavlovian conditioning, evolutionary theory, and psychology of science. More generally, John was a scientist to the core who served as a role model to those who knew him. His career centered on the values of science and rigorous critical thinking based in empirical data, coupled with a curiosity and openness to different and new ideas in psychology.

Outcomes of Operatively Managed Lumbar and Sacral Facet Fractures in Pediatric Athletes: A Case Series

BACKGROUND

Facet fractures have been reported in a total of 6 young athletes in 4 previous publications. These injuries were not diagnosed on magnetic resonance imaging (MRI) or radiographs, and were identified on computed tomography (CT). Our purpose was to report a series of athletes with operatively managed facet fractures. This may be an under-recognized diagnosis.

METHODS

Retrospective review of pediatric patients with operatively managed isolated lumbar or sacral facet fractures from 3 tertiary pediatric hospitals from 2014 to 2019. Clinical records and imaging studies were reviewed.

RESULTS

Ten patients with symptomatic lumbar or sacral facet fractures met inclusion criteria (mean age at presentation; 13.3±2.1 years, 70% Female). All patients reported competitive participation in sports. On physical examination, 10/10 (100%) of patients had lower back pain that was exacerbated with lumbar spine extension. Limited CT scans demonstrated facet fractures in 10/10 (100%) patients not detected on plain film or MRI. All patients experienced significant relief of pain following excision of the facet fracture fragment. At time of first postoperative visit, 9/10 (90%) patients were pain free while one had generalized back pain thought to be related to fibromyalgia and not facet pathology. At time of last follow-up, 2/10 (20%) of patients reported nonspecific back pain that was not localized in the area of the facet fracture, while 80% (8/10) remained pain free. All patients 100% (10/10) returned to full participation to sports. There were no complications noted in this series. Average follow-up was 27 months (range: 1 to 68 mo).

CONCLUSIONS

Athletes with localized back pain exacerbated by spine extension may have a facet fracture. As facet fractures are usually not identified with radiographs or MRI, a limited CT scan should be considered in the evaluation of pediatric athletes with localized back pain exacerbated by extension. In this series, surgical excision of facet fracture fragments was safe and provided predictable pain relief.

Canadian Internal Medicine Ultrasound (CIMUS) Expert Consensus Statement on the Use of Lung Ultrasound for the Assessment of Medical Inpatients With Known or Suspected Coronavirus Disease 2019

OBJECTIVES

To develop a consensus statement on the use of lung ultrasound (LUS) in the assessment of symptomatic general medical inpatients with known or suspected coronavirus disease 2019 (COVID-19).

METHODS

Our LUS expert panel consisted of 14 multidisciplinary international experts. Experts voted in 3 rounds on the strength of 26 recommendations as "strong," "weak," or "do not recommend." For recommendations that reached consensus for do not recommend, a fourth round was conducted to determine the strength of those recommendations, with 2 additional recommendations considered.

RESULTS

Of the 26 recommendations, experts reached consensus on 6 in the first round, 13 in the second, and 7 in the third. Four recommendations were removed because of redundancy. In the fourth round, experts considered 4 recommendations that reached consensus for do not recommend and 2 additional scenarios; consensus was reached for 4 of these. Our final recommendations consist of 24 consensus statements; for 2 of these, the strength of the recommendations did not reach consensus.

CONCLUSIONS

In symptomatic medical inpatients with known or suspected COVID-19, we recommend the use of LUS to: (1) support the diagnosis of pneumonitis but not diagnose COVID-19, (2) rule out concerning ultrasound features, (3) monitor patients with a change in the clinical status, and (4) avoid unnecessary additional imaging for patients whose pretest probability of an alternative or superimposed diagnosis is low. We do not recommend the use of LUS to guide admission and discharge decisions. We do not recommend routine serial LUS in patients without a change in their clinical condition.

Early-Onset Spinal Deformity in Neurofibromatosis Type 1: Natural History, Treatment, and Imaging Surveillance

»

Early-onset scoliosis (EOS) or kyphosis is common in patients with neurofibromatosis (NF) and is characterized by rapid progression of deformity.

»

Traditional growing rods provide good functional and deformity outcomes in patients with NF and EOS; magnetically controlled growing rods (MCGRs) also provide good deformity correction, although high rates of revision have been reported after their use.

»

Among patients with NF type 1 (NF1), morphologic characteristics of the spinal deformity are different in those with paraspinal neurofibromas than in those without paraspinal tumors.

»

Patients with NF1 are at low risk for developing malignant peripheral nerve sheath tumors during childhood (<1%) and their lifetime (8% to 12%), and routine imaging surveillance for malignancy in the absence of symptoms should be clinically directed.

»

Further investigation is needed to standardize screening for EOS in children with NF1 and to develop guidelines for ideal imaging modalities, including their frequency and a timeline.

Under pressure: pressure-dependent pontine compression by a dolichoectasia basilar artery, a case report

Basilar artery dolichoectasia can lead to ischemic stroke through thrombosis of small perforating vessels of the brainstem. Here we report the case of a patient with transient paramedian pontine syndrome in the setting of a hypertensive crisis, finding a dolichoectasia basilar artery compressing on the ventral surface of the pons. The outcome was near-complete resolution of deficits after blood pressure control. We propose increased basilar artery pulse pressure as a novel mechanism of transient compression of the brainstem by a dolichoectasia artery.

Abstract P355: Real-Word Performance of Two Automated Software Platforms for Identification of Salvageable Tissue in Stroke Patients: A Single Center Experience

Background and purpose: Modern stroke treatment has been revolutionized by image-guided selection of patients for endovascular thrombectomy. Current automated platforms allow for real-time identification of large vessel occlusion and salvageable brain tissue. We sought to evaluate the performance of these platforms with regard to identification of infarcted and salvageable tissue.

Methods: We studied all patients that presented to Henry Ford Health System hospitals over a period of 6 weeks, received CT perfusion imaging of the brain upon initial presentation. The images were processed with two automated software platforms. We prospectively measured volumes of tissue with cerebral blood flow (CBF) < 30% of contralateral hemisphere, Tmax >6 secs, and hypoperfusion indices (defined as the ratio of volumes Tmax>10 secs and Tmax>6 secs). We compared the outputs of the two platforms and analyzed the performance of each platform.

Results: 66 scans were included in our study. Both platforms were able to image all stroke patients within their FDA-approved indications. With regard to all scans, both platforms were noted to demonstrate comparable CBF<30% volumes (6.32 ml. vs 4.97 ml, p=0.276), and hypoperfusion indices (0.278 vs 0.338, p=0.344). However, there was statistically significant discrepancy in the volumes of tissue with Tmax>6 secs (23.96 vs 14.18 ml, p=0.023). Analysis of a subset of 12 scans, with evidence of LVO or severe symptomatic stenosis on corresponding CTA, showed again comparable CBF<30% volumes (12.84 ml vs 13.67 ml, p=0.725), and hypoperfusion indices (0.344 vs 0.314, p=0.699). However, the Tmax>6 secs volume discrepancy was greater and still statistically significant (75.54 ml vs 39.58 ml, p=0.048)

Conclusions: Automated software platforms are an invaluable aid in the identification of salvageable tissue, and selection of patients for endovascular thrombectomy in the 6-24 hour window. However, the substantial difference in the identified volumes of hypoperfused tissue-at-risk may result in largely different clinical decisions and patient outcomes. Further validation efforts (and harmonization of algorithms) are required. Stroke teams should be aware of the limitations of automated analysis and need for expert review.

AmAMP1 from Acropora millepora and damicornin define a family of coral-specific antimicrobial peptides related to the Shk toxins of sea anemones

A candidate antimicrobial peptide (AmAMP1) was identified by searching the whole genome sequence of Acropora millepora for short (<125AA) cysteine-rich predicted proteins with an N-terminal signal peptide but lacking clear homologs in the SwissProt database. It resembled but was not closely related to damicornin, the only other known AMP from a coral, and was shown to be active against both Gram-negative and Gram-positive bacteria. These proteins define a family of AMPs present in corals and their close relatives, the Corallimorpharia, and are synthesised as preproproteins in which the C-terminal mature peptide contains a conserved arrangement of six cysteine residues. Consistent with the idea of a common origin for AMPs and toxins, this Cys motif is shared between the coral AMPs and the Shk neurotoxins of sea anemones. AmAMP1 is expressed at late stages of coral development, in ectodermal cells that resemble the "ganglion neurons" of Hydra, in which it has recently been demonstrated that a distinct AMP known as NDA-1 is expressed.

Intravenous tPA for Acute Ischemic Stroke in Patients with COVID-19

BACKGROUND/PURPOSE

Coronavirus disease 2019 (COVID-19) is associated with increased risk of acute ischemic stroke (AIS), however, there is a paucity of data regarding outcomes after administration of intravenous tissue plasminogen activator (IV tPA) for stroke in patients with COVID-19.

METHODS

We present a multicenter case series from 9 centers in the United States of patients with acute neurological deficits consistent with AIS and COVID-19 who were treated with IV tPA.

RESULTS

We identified 13 patients (mean age 62 (±9.8) years, 9 (69.2%) male). All received IV tPA and 3 cases also underwent mechanical thrombectomy. All patients had systemic symptoms consistent with COVID-19 at the time of admission: fever (5 patients), cough (7 patients), and dyspnea (8 patients). The median admission NIH stroke scale (NIHSS) score was 14.5 (range 3-26) and most patients (61.5%) improved at follow up (median NIHSS score 7.5, range 0-25). No systemic or symptomatic intracranial hemorrhages were seen. Stroke mechanisms included cardioembolic (3 patients), large artery atherosclerosis (2 patients), small vessel disease (1 patient), embolic stroke of undetermined source (3 patients), and cryptogenic with incomplete investigation (1 patient). Three patients were determined to have transient ischemic attacks or aborted strokes. Two out of 12 (16.6%) patients had elevated fibrinogen levels on admission (mean 262.2 ± 87.5 mg/dl), and 7 out of 11 (63.6%) patients had an elevated D-dimer level (mean 4284.6 ±3368.9 ng/ml).

CONCLUSIONS

IV tPA may be safe and efficacious in COVID-19, but larger studies are needed to validate these results.

Water-polyamide chemical interplay in desalination membranes explored by ambient pressure X-ray photoelectron spectroscopy

Reverse osmosis using aromatic polyamide membranes is currently the most important technology for seawater desalination. The performance of reverse osmosis membranes is highly dependent on the interplay of their surface chemical groups with water and water contaminants. In order to better understand the underlying mechanisms of these membranes, we study ultrathin polyamide films that chemically resemble reverse osmosis membranes, using ambient pressure X-ray photoelectron spectroscopy. This technique can identify the functional groups at the membrane-water interface and allows monitoring of small shifts in the electron binding energy that indicate interaction with water. We observe deprotonation of free acid groups and formation of a 'water complex' with nitrogen groups in the polymer upon exposure of the membrane to water vapour. The chemical changes are reversed when water is removed from the membrane. While the correlation between functional groups and water uptake is an established one, this experiment serves to understand the nature of their chemical interaction, and opens up possibilities for tailoring future materials to specific requirements.

Vertical Profiles of Droplet Size Distributions Derived from Cloud-Side Observations by the Research Scanning Polarimeter: Tests on Simulated Data

The Research Scanning Polarimeter (RSP) is an airborne along-track scanner measuring the polarized and total reflectances with high angular resolution. It allows for accurate characterization of liquid water cloud droplet sizes using the rainbow structure in the polarized reflectance. RSP's observations also provide constraints on the cumulus cloud's 2D cross section, yielding estimates of its geometric shape. In this study for the first time we evaluate the possibility to retrieve vertical profiles of microphysical characteristics along the cloud side by combining these micro- and macrophysical retrieval methods. First we constrain cloud's geometric shape, then for each point on the bright side of its surface we collect data from different scans to obtain the multi-angle polarized reflectance at that point. The rainbow structures of the reflectances from multiple points yield the corresponding droplet size distributions (DSDs), which are then combined into vertical profiles. We present the results of testing the proposed profiling algorithm on simulated data obtained using large eddy simulations and 3D radiative transfer computations. The virtual RSP measurements were used for retrieval of DSD profiles, which then were compared to the actual data from the LES-model output. A cumulus congestus cloud was selected for these tests in preparation for analysis of real measurements made during the Cloud, Aerosol and Monsoon Processes Philippines Experiment (CAMP²Ex). We demonstrate that the use of the non-parametric Rainbow Fourier Transform (RFT) allows for adequate retrieval of the complex altitude-dependent bimodal structure of cloud DSDs.

Rational Design of Ion Exchange Membrane Material Properties Limits the Crossover of CO2 Reduction Products in Artificial Photosynthesis Devices

Efficient operation is crucial for the deployment of photoelectrochemical CO₂ reduction devices for large-scale artificial photosynthesis. In these devices, undesired transport of CO₂ reduction products from the reduction electrode to the oxidation electrode may occur through a liquid electrolyte and an ion exchange membrane, reducing device productivity and increasing the energy required for product purification. Our work investigated the CO₂ reduction product crossover through ion exchange membranes separating the cathode and anode compartments in CO₂ reduction cells. The concentrations of liquid products produced by CO₂ reduction on copper foil were measured. A systematic approach for the investigation of product crossover was developed. The crossover of products was analyzed over a range of working electrode potentials (-1.08 V vs RHE to -0.88 V vs RHE) in cells employing a commercial Selemion AMV membrane and a new poly(vinylimidazolium) family of ion exchange membranes with variable chemical and structural properties. We found that product loss due to electromigration of charged species in the device was more significant than product loss due to diffusion of uncharged species. To reduce the crossover of CO₂ reduction products, the influence of membrane properties such as the ionic conductivity and water volume fraction was investigated for the Selemion AMV membrane and poly(vinylimidazolium) membranes with variable material properties. We show that the water volume fraction and, by extension, ionic conductivity of the membrane may be controlled to reduce product crossover in CO₂ reduction artificial photosynthesis devices.

Interactions within and between parallel parietal-frontal networks involved in complex motor behaviors in prosimian galagos and a squirrel monkey

Long-train intracortical microstimulation (ICMS) of motor (M1) and posterior parietal cortices (PPC) in primates reveals cortical domains for different ethologically relevant behaviors. How functional domains interact with each other in producing motor behaviors is not known. In this study, we tested our hypothesis that matching domains interact to produce a specific complex movement, whereas connections between nonmatching domains are involved in suppression of conflicting motor outputs to prevent competing movements. In anesthetized galagos, we used 500-ms trains of ICMS to evoke complex movements from a functional domain in M1 or PPC while simultaneously stimulating another mismatched or matched domain. We considered movements of different and similar directions evoked from chosen cortical sites distant or close to each other. Their trajectories and speeds were analyzed and compared with those evoked by simultaneous stimulation. Stimulation of two sites evoking same or complementary movements produced a similar but more pronounced movement or a combined movement, respectively. Stimulation of two sites representing movements of different directions resulted in partial or total suppression of one of these movements. Thus interactions between domains in M1 and PPC were additive when they were functionally matched across fields or antagonistic between functionally conflicting domains, especially in PPC, suggesting that mismatched domains are involved in mutual suppression. Simultaneous stimulation of unrelated domains (forelimb and face) produced both movements independently. Movements produced by the simultaneous stimulation of sites in domains of two cerebral hemispheres were largely independent, but some interactions were observed.NEW & NOTEWORTHY Long trains of electrical pulses applied simultaneously to two sites in motor cortical areas (M1, PPC) have shown that interactions of functionally matched domains (evoking similar movements) within these areas were additive to produce a specific complex movement. Interactions between functionally mismatched domains (evoking different movements) were mostly antagonistic, suggesting their involvement in mutual suppression of conflicting motor outputs to prevent competing movements. Simultaneous stimulation of unrelated domains (forelimb and face) produced both movements independently.

Releasing the tether: Weight normalization following corrective spinal fusion in cerebral palsy

PURPOSE

Feeding difficulties are common among patients with cerebral palsy (CP) and neuromuscular (NM) scoliosis. We theorize that posterior spinal fusion (PSF) reduces intra-abdominal pressure, resulting in improved feeding and subsequent weight gain. We hypothesized that, among nonambulatory patients with CP and NM scoliosis, we would observe significant gain in weight following PSF.

METHODS

Fifty subjects with nonambulatory CP who underwent PSF for NM scoliosis were included. Age and weight were recorded for the preoperative year; on the day of surgery; and at 6-month, 1-year, and 2-year follow-up. Weights were converted to weight percentiles using CP-specific growth charts. The weight percentile distributions were compared between time points using descriptive statistics as well as regression analysis.

RESULTS

The average change in weight from the day of surgery to 2-year follow-up was +3.4 percentiles. Patients who started out under the 50th percentile gained an average of 17.3 percentiles in the first year after PSF ( p = 0.009). Regression analysis showed that patients with baseline weight <50th percentile tended to gain in weight percentile over the first postoperative year ( β = 1.990, p = 0.001). No trend was present among this group prior to surgery ( p = 0.692) or during the second postoperative year ( p = 0.945). No trends were noted prior to or after surgery for patients with baseline weights ≥50th percentile. No significant association was observed between curve severity (measured by preoperative Cobb angle) and weight change.

CONCLUSIONS

This series is the first to document significant weight gain after PSF for NM scoliosis, supporting the theory that spinal correction improves digestive function.

LEVEL OF EVIDENCE

Prognostic level II.

Shared and derived features of cellular diversity in the human cerebral cortex

The cerebral cortex is the hallmark of the mammalian nervous system, and its large size and cellular diversity in humans support our most sophisticated cognitive abilities. Although the basic cellular organization of the cortex is conserved across mammals, cells have diversified during evolution. An increasingly integrated taxonomy of cell types, especially with the advent of single-cell transcriptomic data, has revealed an unprecedented variety of human cortical cell subtypes. Here, we broadly review the cellular composition and diversity of the mammalian brain, and how progenitor pools generate cell subtypes during development. We then discuss human cortical cells that are distinct from rodent cells, as well as the challenges and advantages of using model systems to study human cell types in health and disease.

Abstract WP7: Does Administration of IV Contrast Impact Outcomes on Acute Ischemic Stroke Patients? A Propensity Score Matched Single Center Study

Introduction: The AHA/ASA strongly recommend urgent noninvasive vascular imaging for suspected LVO patients. 1 There remains concern about developing acute kidney injury (AKI) and/or contrast induced nephropathy (CIN) secondary to contrast exposure for CTA or DSA. 2-8 It is unclear if contrast has any impact upon outcomes of endovascular thrombectomy (ET) patients, and if this differs from patients who do not undergo ET.

Methods: A retrospective chart review was conducted upon 2384 consecutive patients who were admitted with acute ischemic stroke from 1/2014 - 8/2017. Patients were grouped into: ET (CTA+DSA), CTA Only, and No Contrast. Propensity score matching (PSM) was conducted for a 1:1:1 match between these 3 groups. The primary outcome was 90-day modified rankin scal (mRS). Patients were grouped into favorable (mRS ≤ 2) and unfavorable (mRS > 2). AKI was defined as an increase in serum creatinine (SCr) ≥ 0.3 within 48 hours while CIN was defined as an increase in SCr ≥ 0.5 or 25% at 48 - 72 hours 9 .

Results: 124 patients were matched into each group. Patients that received contrast had higher rates of AKI at 48-72 hours; however, this was not statistically significant (8% CTA+DSA, 5% CTA only, and 3% no contrast, p = 0.228). Patients with poor outcome amongst all groups had statistically significant higher rates of baseline CKD (37% vs 24%, p = 0.038) and AKI (22% vs 11%, p = 0.025). Multivariable analysis for the ET subgroup shows no significant difference in outcomes with or without AKI; however, in the non-ET subgroup, presence of AKI was significantly associated with poor outcome (OR 1.25 (0.36, 4.34) and 19.05 (2.13, 170.72), respectively; p < 0.05).

Conclusion: Rates of AKI do not differ significantly based on the administration of contrast. In our PSM population, those not undergoing ET have poorer outcomes if they suffer AKI; however, there is no difference in outcomes if patients receive ET.

Spatiotemporal transcriptomic divergence across human and macaque brain development

Human nervous system development is an intricate and protracted process that requires precise spatiotemporal transcriptional regulation. We generated tissue-level and single-cell transcriptomic data from up to 16 brain regions covering prenatal and postnatal rhesus macaque development. Integrative analysis with complementary human data revealed that global intraspecies (ontogenetic) and interspecies (phylogenetic) regional transcriptomic differences exhibit concerted cup-shaped patterns, with a late fetal-to-infancy (perinatal) convergence. Prenatal neocortical transcriptomic patterns revealed transient topographic gradients, whereas postnatal patterns largely reflected functional hierarchy. Genes exhibiting heterotopic and heterochronic divergence included those transiently enriched in the prenatal prefrontal cortex or linked to autism spectrum disorder and schizophrenia. Our findings shed light on transcriptomic programs underlying the evolution of human brain development and the pathogenesis of neuropsychiatric disorders.

Self-concept orientation and organizational identification: a mediated relationship

Purpose

The purpose of this paper is to test a mediated model of the relationship between self-concept orientation (individualist and collectivist) and organizational identification (OrgID, Cooper and Thatcher, 2010), with proposed mediators including the need for organizational identification (nOID, Glynn, 1998) as well as self-presentation concerns of social adjustment (SA) and value expression (VE, Highhouse et al., 2007).

Design/methodology/approach

Data were collected from 509 participants in seven countries. Direct and mediation effects were tested using structural equation modeling (AMOS 25.0).

Findings

Individualist self-concept orientation was positively related to VE and collectivist self-concept orientation was positively related to nOID, VE and SA. VE mediated the relationship between both self-concept orientations and OrgID. In addition, nOID mediated the relationship for collectivist self-concept orientation.

Practical implications

This study identifies underlying psychological needs as mediators of the relationship of self-concept orientation to OrgID. Understanding these linkages enables employers to develop practices that resonate with the self-concept orientations and associated psychological needs of their employees, thereby enhancing OrgID.

Originality/value

This study provides a significant contribution to the OrgID literature by proposing and testing for relationships between self-concept orientations and OrgID as mediated by underlying psychological needs. The results provide support for the mediated model as well as many of Cooper and Thatcher’s (2010) theoretical propositions, with notable exceptions.

Cerebrovascular injuries found in acute type B aortic dissections are associated with blood pressure derangements and poor outcome

OBJECTIVE

Cerebrovascular injury (CVI) is a recognized but underappreciated complication of acute type B aortic dissection (ATBAD). This study was performed to determine risk factors for CVI associated with ATBAD and, in particular, the possible contributory role of aggressive anti-impulse therapy.

METHODS

A retrospective review of all patients presenting to a tertiary medical center with an ATBAD between January 2003 and October 2012 was conducted. All CVIs were adjudicated by a vascular neurologist and assigned a probable cause. The initial intensity of anti-impulse therapy was defined as the difference in mean arterial pressure (ΔMAP) from presentation to subsequent admission to the intensive care unit.

RESULTS

A total of 112 patients were identified. The average age was 61 years; 64% were male, and 59% were African American. Twenty patients required operative intervention (14 thoracic endovascular aortic repairs and 6 open). CVI occurred in 13 patients (11.6%): 9 were hypoperfusion related (6 diffuse hypoxic brain injuries and 3 watershed infarcts), 2 were procedure related (both thoracic endovascular aortic repairs), 1 was an intracranial hemorrhage on presentation, and 1 was a probable embolic stroke on presentation. CVI patients had demographics and comorbidities comparable to those of the non-CVI patients. CVI was associated with operative intervention (54% vs 13%; P = .002). Thirty-day mortality was significantly higher in CVI patients (54% vs 6%; P < .001). Patients who suffered a hypoperfusion brain injury had a higher MAP on presentation to the emergency department (142 mm Hg vs 120 mm Hg; P = .034) and a significantly greater reduction in MAP (ΔMAP 49 mm Hg vs 15 mm Hg; P < .001) by the time they reached the intensive care unit compared with the non-CVI patients.

CONCLUSIONS

In our series, CVI in ATBAD is more frequent than previously reported and is associated with increased mortality. The most common causes are related to cerebral hypoperfusion. Higher MAP on presentation and greater decline in MAP are associated risk factors for hypoperfusion-related CVI. A less aggressive approach to lowering MAP in ATBAD warrants further study in an attempt to reduce CVI in ATBAD.

A Practical Guide to Avoiding and Managing Complications in Pediatric Spinal Deformity Surgery

Despite recent research and improvements in spinal implants, complications remain frequent in patients who undergo pediatric spinal deformity surgery. Although the rate of neurologic injury after pediatric spinal deformity surgery is low, the rate of surgical site infection after pediatric spinal deformity surgery is high, particularly in patients who have neuromuscular scoliosis. Although symptomatic implant complications that require revision surgery are rare with the use of modern spinal fusion constructs, they are common in patients who have early-onset scoliosis. Patients who have perioperative respiratory or gastrointestinal complications benefit from early recognition and supportive treatment. The cause of perioperative complications in patients who undergo pediatric spinal deformity surgery often is multifactorial; therefore, surgeons should understand the numerous risk factors for and strategies for the prevention of pediatric spinal deformity surgery complications.

Abstract WP353: Decreasing "Door to Admission" Times for Intravenous tPA Treated Patients: A Single Comprehensive Stroke Center Experience

Introduction: AHA’s Get with The Guidelines (GTWG) initiative has recommended “door to admission” time for patients receiving IV tPA to be <3 hours. In large tertiary hospitals like ours, complicated administrative steps and coordination required to admit patients often leads to delays. There has been a paucity of studies aiming to streamline this process for patients treated with IV tPA.

Aim: To assess whether having a dedicated rapid response team (RRT) RN within the ED to coordinate care of patients receiving IV tPA reduces “door to admission” times.

Methods: A policy of notifying RRT of all patients eligible for IV tPA was implemented in the ED. The responsibility of RRT was to coordinate care between neurology resident, ED nurse, acute stroke unit (ASU) charge nurse and admissions office to ensure timely completion of steps required for admission. “Door to admission” times were collected prospectively for 3 months before and after intervention. The compliance of recording neuro checks and vital signs per AHA guidelines for post tPA care were also measured. Wilcoxon two sample test was used to analyze time variables and compliance rates.

Results: The post intervention group had significantly decreased “door to admission” and “bolus to admission” times (see table). Also, significantly fewer patients had &gt;1 vital signs checks miss in post-intervention group (6% vs 38%; p=0.033). There was no significant increase in the compliance rate of neuro checks.

Discussion: By adding RRT in coordination of care for IV tPA patients in the ED, we were able to drastically reduce our door to admission times. The improvement was because of faster placement and prioritized processing of the admission orders. RRT acted as a “control center” relaying vital information to admission office and ASU charge nurse. This also freed ED RN to improve compliance rate of recording vital signs in IV tPA patients. Similar interventions can be used by other centers to decrease their “door to admission” times.

Abstract WP311: A Widely Accepted Metric (Telephone Assessment of the Modified Rankin Scale Score at 90 Days) May Not Accurately Reflect the Real-Life Outcome of Endovascular Stroke Treatment

Introduction: The modified Rankin Score (mRS) collected at approximately 90 days after stroke onset is a reliable and reproducible measure of stroke outcome. It was utilized in the randomized controlled trials that established the safety and efficacy of endovascular stroke treatment. It has been incorporated as a core metric for measuring quality of care in comprehensive stroke centers. We aimed to evaluate the value of the 90-day mRS considering that a certain percentage of patients may fail to respond to coordinator phone calls.

Methods: We retrospectively analyzed patients who received endovascular stroke treatment in a comprehensive stroke center from January 2015 to March 2017, and who were prospectively enrolled in the Get With The Guidelines-Stroke Registry. We calculated the response rates to coordinator phone calls at approximately 90 days from stroke onset. Several calls were placed according to the established institutional policy. We compared the response rates of patients who had successful or unsuccessful recanalization, as reported by the endovascular specialist at the time of the procedure.

Results: We identified 79 patients who received endovascular treatment, and who were contacted by the coordinators at approximately 90 days after stroke onset. 58 patients had successful recanalization (as defined by reported TICI grades IIb and III), whereas 21 patients had unsuccessful recanalization (as defined by reported TICI grades O, I, and IIa). 44/58 patients with successful recanalization responded to coordinator calls, compared to 11/21 patients with unsuccessful recanalization. The difference in proportions was statistically significant (p=0.045).

Conclusions: Patients who have unsuccessful recanalization after endovascular stroke treatment are significantly less likely to respond to coordinator calls. Therefore, their mRS cannot be estimated, and the long-term outcome of the endovascular procedure cannot be assessed. Since these patients are more likely to have died, or be in a supervised facility (and therefore not accessible at their previous phone number), the telephone assessment of the mRS is likely not an accurate measure for the long-term therapeutic effect of endovascular stroke treatment.

Abstract WP324: Improving Stroke Care Delivery for In-Hospital Stroke Alerts by Addition of Overhead "Code Stroke" Announcements: Single Comprehensive Stroke Center’s Experience

Introduction: In-hospital strokes account for 2-17% of all stroke patients. Mobilization of resources for in-hospital strokes is challenging and it takes longer to complete the necessary evaluations as compared to those presenting to the emergency room. Dedicated “stroke code teams” for in-hospital stroke patients have been shown to improve the adherence to the AHA’s get with the guidelines (GWTG) initiative but there is a paucity of research analyzing this process.

Aim: To assess whether the addition of an overhead “code stroke” announcement to an existing group paging system for in-hospital strokes decreases the time required for obtaining the necessary evaluations.

Methods: An overhead “code stroke” announcement and process education was introduced at our hospital in addition to the existing stroke group paging system. We analyzed prospectively collected time based measures for in-hospital stroke code activations 4 months before and after implementation. Wilcoxon two-sample test was used to analyze the relevant time variables between the two groups.

Results: The post-stroke group had significantly shorter times from stroke alert to CT and CTA interpretation, time from symptom onset to CT and CTA interpretation, and time for CT and CTA interpretation when compared to the pre-stroke alert group (see table). The post-stroke alert period captured significantly more acute strokes than the pre-stroke alert period (6.25 vs 1.75 per month, p=0.001 from binomial test).

Conclusion: The addition of an overhead “code stroke” along with process education can drastically reduce important GWTG’s acute stroke evaluation times at a comprehensive stroke center. We suggest that improved coordination between the services, along with the urgency associated with an overhead “code stroke”, led to improvement in the evaluation times. We also noted an increase in the number of stroke-code activations, probably due to increased perception and awareness of stroke as a true emergency.

Iliac crest apophyseal insufficiency avulsion fractures

Iliac crest apophyseal avulsion fractures are rare injuries caused mainly through forceful contraction of attached muscles during high level sporting activities. We present the first case of a spontaneous iliac crest apophyseal avulsion insufficiency fracture in a patient with severe atopic eczema on oral steroids and review the relevant literature.

PHYSIOLOGY AND ENDOCRINOLOGY SYMPOSIUM: Postnatal reproductive development and the lactocrine hypothesis

Maternal effects on development can program cell fate and dictate offspring phenotype. Such effects do not end at birth, but extend into postnatal life through signals communicated from mother to offspring in first milk (colostrum). Transmission of bioactive factors from mother to offspring as a specific consequence of nursing defines a lactocrine mechanism. The female reproductive tract is not fully formed at birth (postnatal day = PND 0). Data for ungulates and mice indicate that disruption of development during neonatal life can have lasting effects on the form and function of uterine tissues. Uterine growth and histogenesis proceed in an ovary-independent manner shortly after birth, suggesting that extra-ovarian inputs are important in this process. Data for the pig indicate that lactocrine signals communicated within 12 to 48 h from birth constitute one source of such uterotrophic support. Disruption of lactocrine signaling, either naturally, by limited colostrum consumption, or experimentally, by milk replacer feeding, alters neonatal porcine uterine development and can have negative consequences for reproductive performance in adults. Substantial differences in endometrial and uterine gene expression between colostrum- and replacer-fed gilts were evident by PND 2, when RNA sequencing revealed over 800 differentially expressed, lactocrine-sensitive genes. Lactocrine-sensitive biological processes identified through transcriptomic studies and integrated microRNA-mRNA pathway analyses included those associated with both cell-cell and ESR1 signaling, and tissue development. Evidence for the pig indicates that colostrum consumption and lactocrine signaling are required to establish a normal uterine developmental program and optimal uterine developmental trajectory.

Creation of an Online Wiki Improves Post-Operative Surgical Protocol Adherence in Arthroplasty Patients

BACKGROUND

Perioperative care pathways are tools used in high-volume clinical settings to standardize care, reduce variability, and improve outcomes. However, the mechanism by which the information is transmitted to other caregivers is often inconsistent and error-prone. At our institution, we developed an online, user-editable ("wiki") database to communicate post-operative protocols. The purpose of this study is to evaluate the hypothesis that implementation of the wiki would improve protocol adherence and reduce unintentional deviations inpatient care.

METHODS

We conducted a retrospective review of patients who underwent primary lower extremity arthroplasty at our institution during three 6-month time periods including immediately before, 6 months after, and 2 years following introduction of the wiki. Adherence to defined perioperative care pathways (laboratory studies, post-operative imaging, perioperative antibiotics, and inpatient pain medications) was compared between the groups.

RESULTS

After wiki implementation, adherence to protocols improved significantly for laboratory orders (P < .0001), imaging (P < .001), pain control regimen (P = .03), and overall protocol adherence (P < .001). Improvements were seen in some areas almost immediately, while others did not show improvements until 2 years after implementation. Costs associated with unnecessary testing were reduced by 82%.

CONCLUSION

Development of an online wiki for tracking post-operative protocols improves care pathway adherence and reduces variability in care while lowering costs associated with unnecessary testing, although some benefits may not be immediately realized. Several practical barriers to implementing the wiki are also discussed, along with proposed solutions.

Lactadherin is a candidate oviduct Lewis X trisaccharide receptor on porcine spermatozoa

A recent study has demonstrated that porcine spermatozoa recognize with high affinity carbohydrate structures containing Lewis X motifs. Sperm adhesion to Lewis X is proposed to mediate sperm binding to the oviduct epithelium to form a reservoir. The objective of this study was to identify Lewis X-binding proteins from porcine spermatozoa as candidate receptors for oviduct glycans. To identify low-abundance proteins typically masked by proteins originating from seminal fluid, Lewis X candidate receptors were enriched from cauda epididymal boar spermatozoa. Plasma membrane preparations from cauda epididymal spermatozoa were subjected to RP-HPLC and glycan blotting assays to isolate and detect proteins that bind Lewis X. Following bottom-up LC-MS/MS analysis, among the two bands that bound sulfated Lewis X, ADAM5, which spermatozoa, was confidently identified. ADAM family members have been established as contributors to sperm entry into the oviduct. A second sulfated Lewis X-binding protein identified was the peripheral membrane protein lactadherin (also known as P47, SED1 and MFG-E8 in different species). The interaction between Lewis X and lactadherin was functionally important because competitive inhibition by soluble recombinant lactadherin reduced sperm binding to the oviduct epithelium. Furthermore, far-western blotting demonstrated that purified lactadherin could bind oviduct cells. In summary, these findings reveal that, in addition to the previously reported glycan affinity of accessory gland proteins that adhere to spermatozoa, multiple proteins intrinsic to spermatozoa have affinity for a specific oviduct glycan. Further, in addition to binding to the zona pellucida, lactadherin is now implicated in binding to oviduct glycans to promote formation of the sperm reservoir.