Faculty Bibliography

The virtual practice has made major advances in the way that we care for patients in the modern era. The culture of virtual practice, consulting, and telemedicine, which had started several years ago, took an accelerated leap as humankind was challenged by the novel coronavirus pandemic (COVID19). The social distancing measures and lockdowns imposed in many countries left medical care providers with limited options in evaluating ambulatory patients, pushing the rapid transition to assessments via virtual platforms. In this novel arena of medical practice, which may form new norms beyond the current pandemic crisis, we found it critical to define guidelines on the recommended practice in neurotology, including remote methods in examining the vestibular and eye movement function. The proposed remote examination methods aim to reliably diagnose acute and subacute diseases of the inner-ear, brainstem, and the cerebellum. A key aim was to triage patients into those requiring urgent emergency room assessment versus non-urgent but expedited outpatient management. Physicians who had expertise in managing patients with vestibular disorders were invited to participate in the taskforce. The focus was on two topics: (1) an adequate eye movement and vestibular examination strategy using virtual platforms and (2) a decision pathway providing guidance about which patient should seek urgent medical care and which patient should have non-urgent but expedited outpatient management.

There is an absence of specific evidence or guideline recommendations on blood pressure management for large vessel occlusion stroke patients. Until randomized data are available, the periprocedural blood pressure management of patients undergoing endovascular thrombectomy can be viewed in two phases relative to the achievement of recanalization. In the hyperacute phase, prior to recanalization, hypotension should be avoided to maintain adequate penumbral perfusion. The American Heart Association guidelines should be followed for the upper end of prethrombectomy blood pressure: ≤185/110 mm Hg, unless post-tissue plasminogen activator administration when the goal is <180/105 mm Hg. After successful recanalization (thrombolysis in cerebral infarction [TICI]: 2b-3), we recommend a target of a maximum systolic blood pressure of < 160 mm Hg, while the persistently occluded patients (TICI < 2b) may require more permissive goals up to <180/105 mm Hg. Future research should focus on generating randomized data on optimal blood pressure management both before and after endovascular thrombectomy, to optimize patient outcomes for these divergent clinical scenarios.

Subependymal giant-cell astrocytomas (SEGAs) are slow-growing brain tumors that are a hallmark feature seen in 5-10% of patients with Tuberous Sclerosis Complex (TSC). Though histologically benign, they can cause serious neurologic symptoms, leading to death if untreated. SEGAs consistently show biallelic loss of TSC1 or TSC2. Herein, we aimed to define other somatic events beyond TSC1/TSC2 loss and identify potential transcriptional drivers that contribute to SEGA formation. Paired tumor-normal whole-exome sequencing was performed on 21 resected SEGAs from 20 TSC patients. Pathogenic variants in TSC1/TSC2 were identified in 19/21 (90%) SEGAs. Copy neutral loss of heterozygosity (size range: 2.2-46 Mb) was seen in 76% (16/21) of SEGAs (44% chr9q and 56% chr16p). An average of 1.4 other somatic variants (range 0-7) per tumor were identified, unlikely of pathogenic significance. Whole transcriptome RNA-sequencing analyses revealed 190 common differentially expressed genes in SEGA (n = 16, 13 from a prior study) in pairwise comparison to each of: low grade diffuse gliomas (n = 530) and glioblastoma (n = 171) from The Cancer Genome Atlas (TCGA) consortium, ganglioglioma (n = 10), TSC cortical tubers (n = 15), and multiple normal tissues. Among these, homeobox transcription factors (TFs) HMX3, HMX2, VAX1, SIX3; and TFs IRF6 and EOMES were all expressed >12-fold higher in SEGAs (FDR/q-value < 0.05). Immunohistochemistry supported the specificity of IRF6, VAX1, SIX3 for SEGAs in comparison to other tumor entities and normal brain. We conclude that SEGAs have an extremely low somatic mutation rate, suggesting that TSC1/TSC2 loss is sufficient to drive tumor growth. The unique and highly expressed SEGA-specific TFs likely reflect the neuroepithelial cell of origin, and may also contribute to the transcriptional and epigenetic state that enables SEGA growth following two-hit loss of TSC1 or TSC2 and mTORC1 activation.

OBJECTIVES/OBJECTIVE:To explore the impact of sex and age on relationship between prodromal constipation and disease phenotype in Parkinson's disease at early stages. METHODS:A total of 385 Parkinson's disease patients from the PRIAMO study were classified according to the presence of prodromal constipation and followed for 24 months. Multivariable mixed-effect models were applied. All analyses were performed separately for sex (64.1% men) and median age (different by sex: 67 years-old in men and 68 years-old in women). RESULTS:As for sex, prodromal constipation was associated with greater odds of attention/memory complaints and apathy symptoms in women only. As for age, prodromal constipation was associated with lower cognitive and higher apathy scores in older patients only. CONCLUSIONS:Prodromal constipation anticipates lower cognitive performances and more severe apathy since the earliest stages in women and older patients. Sex- and age-related heterogeneity of prodromal markers of Parkinson's disease may impact disease phenotype.

BACKGROUND:The coronavirus disease 2019 (COVID-19) pandemic has severely affected ICUs and critical care health-care providers (HCPs) worldwide. RESEARCH QUESTION:How do regional differences and perceived lack of ICU resources affect critical care resource use and the well-being of HCPs? STUDY DESIGN AND METHODS:Between April 23 and May 7, 2020, we electronically administered a 41-question survey to interdisciplinary HCPs caring for patients critically ill with COVID-19. The survey was distributed via critical care societies, research networks, personal contacts, and social media portals. Responses were tabulated according to World Bank region. We performed multivariate log-binomial regression to assess factors associated with three main outcomes: limiting mechanical ventilation (MV), changes in CPR practices, and emotional distress and burnout. RESULTS:We included 2,700 respondents from 77 countries, including physicians (41%), nurses (40%), respiratory therapists (11%), and advanced practice providers (8%). The reported lack of ICU nurses was higher than that of intensivists (32% vs 15%). Limiting MV for patients with COVID-19 was reported by 16% of respondents, was lowest in North America (10%), and was associated with reduced ventilator availability (absolute risk reduction [ARR], 2.10; 95% CI, 1.61-2.74). Overall, 66% of respondents reported changes in CPR practices. Emotional distress or burnout was high across regions (52%, highest in North America) and associated with being female (mechanical ventilation, 1.16; 95% CI, 1.01-1.33), being a nurse (ARR, 1.31; 95% CI, 1.13-1.53), reporting a shortage of ICU nurses (ARR, 1.18; 95% CI, 1.05-1.33), reporting a shortage of powered air-purifying respirators (ARR, 1.30; 95% CI, 1.09-1.55), and experiencing poor communication from supervisors (ARR, 1.30; 95% CI, 1.16-1.46). INTERPRETATION:Our findings demonstrate variability in ICU resource availability and use worldwide. The high prevalence of provider burnout and its association with reported insufficient resources and poor communication from supervisors suggest a need for targeted interventions to support HCPs on the front lines.

Vascular structures in the developing brain are thought to form via angiogenesis from preformed blood vessels in the cephalic mesenchyme. Immunohistochemical studies of developing mouse brain from E10.5-E13.5 revealed the presence of avascular blood islands of primitive erythroid cells expressing the hemangioblast markers (Flk1, Tal1/Scl1, platelet endothelial cell adhesion molecule 1 [PECAM1], vascular endothelial-cadherin [VE-cadherin] and CD34) and an endothelial marker recognized by Griffonia simplicifolia isolectin B4 (IB4) in the cephalic mesenchyme. These cells formed a perineural vascular plexus from which angiogenic sprouts originated and penetrated the neuroepithelium. In addition, avascular isolated cells expressing primitive erythroid, hemangioblast and endothelial makers were visible in the neuroepithelium where they generated vasculogenic and hemogenic foci. From E10.5-E13.5, these vasculogenic foci were a source of new blood vessel formation in the developing brain. In vitro, cultured E13.5 brain endothelial cells contained hemogenic endothelial cells capable of generating erythroid cells. Similar cells were present in primary cultures of dissociated cells from E10.5 embryonic head. Our results provide new evidence that the brain vasculature, like that of the yolk sac and the eye choriocapillaris and hyaloid vascular systems, develops at least in part via hemovasculogenesis, a process in which vasculogenesis and hematopoiesis occur simultaneously.