Cerebral amyloid angiopathy and the immune system.

Cerebral amyloid angiopathy (CAA) is characterized by the accumulation of amyloid protein in the walls of cerebral blood vessels. This deposition of amyloid causes damage to the cerebral vasculature, resulting in blood-brain barrier disruption, cerebral hemorrhage, cognitive decline, and dementia. The role of the immune system in CAA is complex and not fully understood. While the immune system has a clear role in the rare inflammatory variants of CAA (CAA related inflammation and Abeta related angiitis), the more common variants of CAA also have immune system involvement. In a protective role, immune cells may facilitate the clearance of beta-amyloid from the cerebral vasculature. The immune system can also contribute to CAA pathology, promoting vascular injury, blood-brain barrier breakdown, inflammation, and progression of CAA. In this review, we summarize the role of the immune system in CAA, including the potential of immune based treatment strategies to slow vascular disease in CAA and associated cognitive impairment, white matter disease progression, and reduce the risk of cerebral hemorrhage. HIGHLIGHTS: The immune system has a role in cerebral amyloid angiopathy (CAA) which is summarized in this review. There is an inflammatory response to beta-amyloid that may contribute to brain injury and cognitive impairment. Immune cells may facilitate the clearance of beta-amyloid from the cerebral vasculature. Improved understanding of the immune system in CAA may afford novel treatment to improve outcomes in patients with CAA.

Emotional dysmetria after cerebellar-pontine stroke: a case report.

INTRODUCTION: Pseudobulbar affect, or emotional dysregulation, commonly occurs following stroke. However, it is frequently missed in cases involving the cerebellum, resulting in a lack of treatment, which can directly impact stroke rehabilitation. CASE PRESENTATION: A 63-year-old Caucasian female with no history of mood disorders presented with gait instability, dysarthria, and right sided hemiplegia, secondary to cerebellar and pontine ischemic stroke from a basilar occlusion. She underwent endovascular therapy and her deficits gradually improved. However during recovery she began to develop uncontrollable tearfulness while retaining insight that her emotional expression was contextually inappropriate. She was treated with a selective serotonin reuptake inhibitor with reported improvements in her emotional regulation at one year follow up. CONCLUSION: This case highlights cerebellar injury as a potential cause of poorly regulated emotions, or an emotional dysmetria. The recognition of this disorder in patients with cerebellar or pontine strokes is critical, as untreated pseudobulbar affect can impact future stroke rehabilitation.

The Role of Protocadherin γ in Adult Sensory Neurons and Skin Reinnervation.

The clustered protocadherins (cPcdhs) play a critical role in the patterning of several CNS axon and dendritic arbors, through regulation of homophilic self and neighboring interactions. While not explored, primary peripheral sensory afferents that innervate the epidermis may require similar constraints to convey spatial signals with appropriate fidelity. Here, we show that members of the γ-Pcdh (Pcdhγ) family are expressed in both adult sensory neuron axons and in neighboring keratinocytes that have close interactions during skin reinnervation. Adult mice of both sexes were studied. Pcdhγ knock-down either through small interfering RNA (siRNA) transduction or AAV-Cre recombinase transfection of adult mouse primary sensory neurons from floxed Pcdhγ mice was associated with a remarkable rise in neurite outgrowth and branching. Rises in outgrowth were abrogated by Rac1 inhibition. Moreover, AAV-Cre knock-down in Pcdhγ floxed neurons generated a rise in neurite self-intersections, and a robust rise in neighbor intersections or tiling, suggesting a role in sensory axon repulsion. Interestingly, preconditioned (3-d axotomy) neurons with enhanced growth had temporary declines in Pcdhγ and lessened outgrowth from Pcdhγ siRNA. In vivo, mice with local hindpaw skin Pcdhγ knock-down by siRNA had accelerated reinnervation by new epidermal axons with greater terminal branching and reduced intra-axonal spacing. Pcdhγ knock-down also had reciprocal impacts on keratinocyte density and nuclear size. Taken together, this work provides evidence for a role of Pcdhγ in attenuating outgrowth of sensory axons and their interactions, with implications in how new reinnervating axons following injury fare amid skin keratinocytes that also express Pcdhγ.SIGNIFICANCE STATEMENT The molecular mechanisms and potential constraints that govern skin reinnervation and patterning by sensory axons are largely unexplored. Here, we show that γ-protocadherins (Pcdhγ) may help to dictate interaction not only among axons but also between axons and keratinocytes as the former re-enter the skin during reinnervation. Pcdhγ neuronal knock-down enhances outgrowth in peripheral sensory neurons, involving the growth cone protein Rac1 whereas skin Pcdhγ knock-down generates rises in terminal epidermal axon growth and branching during re-innervation. Manipulation of sensory axon regrowth within the epidermis offers an opportunity to influence regenerative outcomes following nerve injury.

Mycoplasma and Ureaplasma Donor-Derived Infection and Hyperammonemia Syndrome in 4 Solid Organ Transplant Recipients From a Single Donor.

Hyperammonemia syndrome (HS) is a life-threatening condition occurring in solid organ transplant patients, affecting primarily lung recipients, and is associated with Mycoplasma hominis and/or Ureaplasma spp infection. The organ donor was a young man who died of hypoxic brain injury and had urethral discharge antemortem. The donor and 4 solid organ transplant recipients had infection with M hominis and/or Ureaplasma spp. The lung and heart recipients both developed altered conscious state and HS associated with M hominis and Ureaplasma spp infections. Despite treatment with antibiotics and ammonia scavengers, both the lung and heart recipients died at day +102 and day +254, respectively. After diagnosis in the thoracic recipients, screening samples from the liver recipient and 1 kidney recipient were culture positive for M hominis with or without Ureaplasma spp. Neither the liver nor kidney recipients developed HS. Our case series demonstrates the unique finding of M hominis and Ureaplasma spp dissemination from an immunocompetent donor across 4 different organ recipients. Phylogenetic whole genome sequencing analysis demonstrated that M hominis samples from recipients and donor were closely related, suggesting donor-derived infection. Screening of lung donors and/or recipients for Mycoplasma and Ureaplasma spp is recommended, as well as prompt treatment with antimicrobials to prevent morbidity.

Oxford cognitive screen: A critical review and independent psychometric evaluation.

The Oxford cognitive screen (OCS) is a stroke-specific cognitive screening assessment. Although the test developers have provided psychometric information for the assessment, the OCS has received minimal external scrutiny, with which to triangulate the underpinning psychometrics. The purpose of this study is to provide a critical review and independent validation of the OCS. This study analysed data from an anonymised clinical database, which consisted of 316 patients who were assessed using the OCS on an Acute Stroke Unit. The rates of impairment on tests of memory and receptive communication were lower than expectation, suggesting that these subtests may be relatively insensitive. Patients with aphasia were more likely to be unable to categorised as impaired on non-language tests, suggesting that they remain sensitive to language processing or non-dominant hand usage. Some of the subtests of the OCS achieve high retest reliability, which makes them good candidates for measuring cognitive change over time. Although the OCS has many advantages, it is also important to adequately consider its limitations, that is insensitivity to memory problems, the potential confounding impact of non-dominant hand usage, and the potential that some tests may sample overall cognitive ability instead of domain-specific functioning.

γ' fibrinogen levels as a biomarker of COVID-19 respiratory disease severity.

Coronavirus disease 2019 (COVID-19) is characterized by a pro-inflammatory state associated with organ failure, thrombosis, and death. We investigated a novel inflammatory biomarker, γ' fibrinogen (GPF), in 103 hospitalized patients with COVID-19 and 19 healthy controls. We found significant associations between GPF levels and the severity of COVID-19 as judged by blood oxygen saturation (SpO2). The mean level of GPF in the patients with COVID-19 was significantly higher than in controls (69.8 (95 % CI 64.8-74.8) mg/dL compared with 36.9 (95 % CI 31.4-42.4) mg/dL, p < 0.0001), whereas C-reactive protein (CRP), lactate dehydrogenase (LDH), and total fibrinogen levels were not significantly different between groups. Mean GPF levels were significantly highest in patients with severe COVID-19 (SpO2 ≤ 93 %, GPF 75.2 (95 % CI 68.7-81.8) mg/dL), compared to mild/moderate COVID-19 (SpO2 > 93 %, GPF 62.5 (95 % CI 55.0-70.0) mg/dL, p = 0.01, AUC of 0.68, 95 % CI 0.57-0.78; Youden's index cutpoint 62.9 mg/dL, sensitivity 0.64, specificity 0.63). In contrast, CRP, interleukin-6, ferritin, LDH, D-dimers, and total fibrinogen had weaker associations with COVID-19 disease severity (all ROC curves with lower AUCs). Thus, GPF may be a useful inflammatory marker of COVID-19 respiratory disease severity.

The Shifting Landscape of Death by Neurologic Criteria in Pediatrics: Current Controversies and Persistent Questions.

Since the concept of death by neurologic criteria (DNC) or "brain death" was articulated by the Harvard Ad Hoc Committee in 1968, efforts to establish and uphold DNC as equivalent to biologic death have been supported through federal and state legislation, professional guidelines, and hospital policies. Despite these endeavors, DNC remains controversial among bioethics scholars and clinicians and is not universally accepted by patient families and the public. In this focused review, we outline the current points of contention surrounding the diagnosis of DNC in pediatric patients. These include physiologic, legal, and philosophical inconsistencies in the definition of DNC, controversy regarding the components of the clinical exam, variability in clinical practice, and ethical concerns regarding justice and role of informed consent. By better understanding these controversies, clinicians may serve families grappling with the diagnosis of DNC more effectively, compassionately, and equitably.

Gamma' fibrinogen levels as a biomarker of COVID-19 respiratory disease severity.

Coronavirus disease 2019 (COVID-19) is characterized by a pro-inflammatory state associated with organ failure, thrombosis, and death. We investigated a novel inflammatory biomarker, γ' fibrinogen (GPF), in 103 hospitalized patients with COVID-19 and 19 healthy controls. We found significant associations between GPF levels and the severity of COVID-19 as judged by blood oxygen saturation (SpO 2 ). The mean level of GPF in the patients with COVID-19 was significantly higher than in controls (69.8 (95% CI 64.8-74.8) mg/dL compared with 36.9 (95% CI 31.4-42.4) mg/dL, p < 0.0001), whereas C-reactive protein (CRP), lactate dehydrogenase (LDH), and total fibrinogen levels were not significantly different between groups. Mean GPF levels were significantly highest in patients with severe COVID-19 (SpO 2 ≤ 93%, GPF 75.2 (95% CI 68.7-81.8) mg/dL), compared to mild/moderate COVID-19 (SpO 2 > 93%, GPF 62.5 (95% CI 55.0-70.0) mg/dL, p = 0.01, AUC of 0.68, 95% CI 0.57-0.78; Youden's index cutpoint 62.9 mg/dL, sensitivity 0.64, specificity 0.63). In contrast, CRP, interleukin-6, ferritin, LDH, D-dimers, and total fibrinogen had weaker associations with COVID-19 disease severity (all ROC curves with lower AUCs). Thus, GPF may be a useful inflammatory marker of COVID-19 respiratory disease severity.

Case Report: COVID-19 Infection and Cervical Artery Dissection.

A 45-year-old woman presented 3 days after symptom resolution from a COVID-19 infection with a left vertebral artery dissection with no known preceding trauma or underlying disposition. She subsequently suffered a left lateral medullary stroke 15 hours after her initial presentation. Cervical artery dissections (CeAD) can occur in the absence of trauma, and in some cases, infection may be a contributing factor. COVID-19 infection can cause an endotheliopathy and inflammatory response, which may contribute to intimal vessel disruption. Whether COVID-19 infection can contribute to CeAD and subsequent stroke is discussed, along with other considerations regarding the pathogenesis of CeAD.

Continued Trauma: A Thematic Analysis of the Asylum-Seeking Experience Under the Migrant Protection Protocols.

Introduction: The Migrant Protection Protocols (MPP) required asylum seekers presenting to the U.S. southern border to wait in Mexico while seeking asylum. Currently, there is a lack of understanding of the MPP's potential harm to an already highly traumatized population. We sought to understand health impacts of this policy, including exposure to continued trauma. Methods: The University of Southern California (USC)'s Keck Human Rights Clinic analyzed de-identified legal declarations and forensic medical affidavits of 11 asylum seekers subjected to MPP. A deductive, thematic analysis was performed to understand the health impact and traumas experienced, and instances of each subtheme were counted by utilizing content analysis methodology. Results: Case analysis identified a total of 36 subthemes. Trauma subthemes included physical assault, psychological abuse, violence against family/friends, witnessed violence, sexual violence, and escalation. Perpetrator subthemes included gang, paramilitary, intimate partner, family, state, and unknown/other. Stress subthemes included despondency and social isolation. Security subthemes included reach of perpetrator, impunity of perpetrator, continued fear of persecution, fear of return, lack of safety, and reliance on strangers. Social determinants of health subthemes included tenuous housing, financial support, food insecurity, health care access, access to employment, and hazardous conditions. Psychological sequelae included anxiety, depressive, post-trauma, and suicidality; physical sequelae included dental, neurological, and dermatological sequelae. Conclusion: The MPP caused harm among these 11 cases evaluated. Harm resulted from continued trauma, worsening social determinants of health, and continued presence of fear and insecurity. The MPP may increase the risk of re-traumatization as well as detract from asylum seekers' ability to heal from pre-migration trauma.

Modulation of complex spike activity differs between zebrin-positive and -negative Purkinje cells in the pigeon cerebellum.

The cerebellum is organized into parasagittal zones defined by its climbing and mossy fiber inputs, efferent projections, and Purkinje cell (PC) response properties. Additionally, parasagittal stripes can be visualized with molecular markers, such as heterogeneous expression of the isoenzyme zebrin II (ZII), where sagittal stripes of high ZII expression (ZII+) are interdigitated with stripes of low ZII expression (ZII-). In the pigeon vestibulocerebellum, a ZII+/- stripe pair represents a functional unit, insofar as both ZII+ and ZII- PCs within a stripe pair respond best to the same pattern of optic flow. In the present study, we attempted to determine whether there were any differences in the responses between ZII+ and ZII- PCs within a functional unit in response to optic flow stimuli. In pigeons of either sex, we recorded complex spike activity (CSA) from PCs in response to optic flow, marked recording sites with a fluorescent tracer, and determined the ZII identity of recorded PCs by immunohistochemistry. We found that CSA of ZII+ PCs showed a greater depth of modulation in response to the preferred optic flow pattern compared with ZII- PCs. We suggest that these differences in the depth of modulation to optic flow stimuli are due to differences in the connectivity of ZII+ and ZII- PCs within a functional unit. Specifically, ZII+ PCs project to areas of the vestibular nuclei that provide inhibitory feedback to the inferior olive, whereas ZII- PCs do not. NEW & NOTEWORTHY Although the cerebellum appears to be a uniform structure, Purkinje cells (PCs) are heterogeneous and can be categorized on the basis of the expression of molecular markers. These phenotypes are conserved across species, but the significance is undetermined. PCs in the vestibulocerebellum encode optic flow resulting from self-motion, and those that express the molecular marker zebrin II (ZII+) exhibit more sensitivity to optic flow than those that do not express zebrin II (ZII-).

Mortality, admission rates and outpatient use among frequent users of emergency departments: a systematic review.

OBJECTIVE: This systematic review examines whether frequent emergency department (ED) users experience higher mortality, hospital admissions and outpatient visits than non-frequent ED users. DESIGN: We published an a priori study protocol in PROSPERO. Our search strategy combined terms for 'frequent users' and 'emergency department'. At least two independent reviewers screened, selected, assessed quality and extracted data. Third-party adjudication resolved conflicts. Results were synthesised based on median effect sizes. DATA SOURCES: We searched seven electronic databases with no limits and performed an extensive grey literature search. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: We included observational analytical studies that focused on adult patients, had a comparison group of non-frequent ED users and reported deaths, admissions and/or outpatient outcomes. RESULTS: The search strategy identified 4004 citations; 374 were screened by full text and 31 cohort and cross-sectional studies were included. Authors used many different definitions to describe frequent users; the overall quality of the included studies was moderate. Across seven studies examining mortality, frequent users had a median 2.2-fold increased odds of mortality compared with non-frequent users. Twenty-eight studies assessing hospital admissions found a median increased odds of admissions per visit at 1.16 and of admissions per patient at 2.58. Ten studies reported outpatient visits with a median 2.65-fold increased risk of having at least one outpatient encounter post-ED visit. CONCLUSIONS: Frequent ED users appear to experience higher mortality, hospital admissions and outpatient visits compared with non-frequent users, and may benefit from targeted interventions. Standardised definitions to facilitate comparable research are urgently needed. REVIEW REGISTRATION NUMBER: PROSPERO (CRD42013005855).

Real-time assessment of nurse work environment and stress.

Ecological momentary assessment methods were used to examine real-time relationships between work environment factors and stress in a sample of 119 registered nurses (RNs) in acute and critical care settings of three hospitals. The RNs carried handheld computers for 1 week of work shifts and were randomly surveyed within 90-min intervals to self-report work activity, perceived workload, and stress. Mixed effects linear regression analyses were completed to predict the stress score in the sample. The number of patients assigned significantly predicted stress; the greater the number of assigned patients, the higher the reported stress (p<.01). Age, gender, adult versus pediatric facility type, familiarity with patients, and proportion of direct care tasks were not significant predictors of stress. Further research is needed to link work environment factors and stress with errors among nurses.

Electron affinities, fluoride affinities, and heats of formation of the second row transition metal hexafluorides: MF(6) (M = Mo, Tc, Ru, Rh, Pd, Ag).

High-level electronic structure calculations were used to evaluate reliable, self-consistent thermochemical data sets for the second row transition metal hexafluorides. The electron affinities, heats of formation, first (MF(6) --> MF(5) + F) and average M-F bond dissociation energies, and fluoride affinities of MF(6) (MF(6) + F(-) --> MF(7)(-)) and MF(5) (MF(5) + F(-) --> MF(6)(-)) were calculated. The electron affinities are higher than those of the corresponding third row hexafluorides, making them stronger one-electron oxidizers. The calculated electron affinities, in good agreement with the available experimental values, are 4.23 eV for MoF(6), 5.89 eV for TcF(6), 7.01 eV for RuF(6), 6.80 eV for RhF(6), 7.95 eV for PdF(6), and 8.89 eV for AgF(6). The corresponding pentafluorides are also very strong Lewis acids, although their acidities on the pF(-) scale are about one unit lower than those of the third row pentafluorides. The performance of a wide range of DFT exchange-correlation functionals was benchmarked by comparing them to our more accurate CCSD(T) results.

Third row transition metal hexafluorides, extraordinary oxidizers, and Lewis acids: electron affinities, fluoride affinities, and heats of formation of WF6, ReF6, OsF6, IrF6, PtF6, and AuF6.

High level electronic structure calculations were used to evaluate reliable, self-consistent thermochemical data sets for the third row transition metal hexafluorides. The electron affinities, heats of formation, first (MF(6) --> MF(5) + F) and average M-F bond dissociation energies, and fluoride affinities of MF(6) (MF(6) + F(-) --> MF(7)(-)) and MF(5) (MF(5) + F(-) --> MF(6)(-)) were calculated. The electron affinities which are a direct measure for the oxidizer strength increase monotonically from WF(6) to AuF(6), with PtF(6) and AuF(6) being extremely powerful oxidizers. The inclusion of spin orbit corrections is necessary to obtain the correct qualitative order for the electron affinities. The calculated electron affinities increase with increasing atomic number, are in good agreement with the available experimental values, and are as follows: WF(6) (3.15 eV), ReF(6) (4.58 eV), OsF(6) (5.92 eV), IrF(6) (5.99 eV), PtF(6) (7.09 eV), and AuF(6) (8.20 eV). A wide range of density functional theory exchange-correlation functionals were also evaluated, and only three gave satisfactory results. The corresponding pentafluorides are extremely strong Lewis acids, with OsF(5), IrF(5), PtF(5), and AuF(5) significantly exceeding the acidity of SbF(5). The optimized geometries of the corresponding MF(7)(-) anions for W through Ir are classical MF(7)(-) anions with M-F bonds; however, for PtF(7)(-) and AuF(7)(-) non-classical anions were found with a very weak external F-F bond between an MF(6)(-) fragment and a fluorine atom. These two anions are text book examples for "superhalogens" and can serve as F atom sources under very mild conditions, explaining the ability of PtF(6) to convert NF(3) to NF(4)(+), ClF(5) to ClF(6)(+), and Xe to XeF(+) and why Bartlett failed to observe XePtF(6) as the reaction product of the PtF(6)/Xe reaction.