Objective: In the setting of the Coronavirus Disease 2019 (COVID-19) global pandemic caused by SARS-CoV-2, a potential association of this disease with stroke has been suggested. We aimed to describe the characteristics of patients who were admitted with COVID-19 and had an acute ischemic stroke (AIS). Methods: This is a case series of PCR-confirmed COVID-19 patients with ischemic stroke admitted to an academic health system in metropolitan Atlanta, Georgia (USA) between March 24th, 2020 and July 17th, 2020. Demographic, clinical, and radiographic characteristics were described. Results: Of 396 ischemic stroke patients admitted during this study period, 13 (2.5%) were also diagnosed with COVID-19. The mean age of patients was 61.6 ± 10.8 years, 10 (76.9%) male, 8 (61.5%) were Black Americans, mean time from last normal was 4.97 ± 5.1 days, and only one received acute reperfusion therapy. All 13 patients had at least one stroke-associated co-morbidity. The predominant pattern of ischemic stroke was embolic with 4 explained by atrial fibrillation. COVID-19 patients had a significantly higher rate of cryptogenic stroke than non-COVID-19 patients during the study period (69% vs 17%, p = 0.0001). Conclusions: In our case series, ischemic stroke affected COVID-19 patients with traditional stroke risk factors at an age typically seen in non-COVID populations, and mainly affecting males and Black Americans. We observed a predominantly embolic pattern of stroke with a higher than expected rate of cryptogenic strokes, a prolonged median time to presentation and symptom recognition limiting the use of acute reperfusion treatments. These results highlight the need for increased community awareness, early identification, and management of AIS in COVID-19 patients.
Parkinson’s disease (PD) is a common age-associated neurodegenerative disorder. Motor symptoms are the cardinal component of PD, but non-motor symptoms, such as dementia, depression, and autonomic dysfunction are being increasingly recognized. Motor symptoms are primarily caused by selective degeneration of substantia nigra dopamine (SNDA) neurons in the midbrain; non-motor symptoms may be referable to well-described pathology at multiple levels of the neuraxis. Development of symptomatic and disease-modifying therapies is dependent on an accurate and comprehensive understanding of the pathogenesis and pathophysiology of PD. Gene expression profiling has been recently employed to assess function on a broad level in the hopes of gaining greater knowledge concerning how individual mechanisms of disease fit together as a whole and to generate novel hypotheses concerning PD pathogenesis, diagnosis, and progression. So far, the majority of studies have been performed on postmortem brain samples from PD patients, but more recently, studies have targeted enriched populations of dopamine neurons and have begun to explore extra-nigral neurons and even peripheral tissues. This review will provide a brief synopsis of gene expression profiling in parkinsonism and its pitfalls to date and propose several potential future directions and uses for the technique. It will focus on the use of microarray experiments to stimulate hypotheses concerning mechanisms of neurodegeneration in PD, since the majority of studies thus far have addressed that complicated issue.
Dopamine (DA) neurons in the substantia nigra (SNDA neurons) are among the most severely affected in Parkinson’s disease (PD). Mitochondrial complex I inhibition by rotenone or MPTP can induce SNDA neurodegeneration and recapitulate motor disability in rodents. We performed a transcriptional analysis of the midbrain response to complex I inhibition focused on selected metabolic transcripts using quantitative real-time RT-PCR in conjunction with laser-capture microdissection (LCM) of immunofluorescently-targeted SNDA and ventral tegmental area (VTA) DA neurons. There were DA neuron-selective alterations in metabolic transcripts in response to generalized complex I inhibition dependent on the behavioral response of the animal, and vulnerable SNDA neurons were more dynamic in their metabolic transcriptional response than less vulnerable VTADA neurons. The metabolic transcriptional response of DA neurons may contribute significantly to the ultimate toxicity associated with mitochondrial inhibition, and better understanding of this response may provide insight into potential targets for neuroprotection in PD.
Understanding the neurochemical composition of the enteric nervous system (ENS) is critical for elucidating neurological function in the gastrointestinal (GI) tract in health and disease. Despite their status as the closest models of human neurological systems, relatively little is known about enteric neurochemistry in nonhuman primates. We describe neurochemical coding of the enteric nervous system, specifically the myenteric plexus, of the rhesus monkey (Macaca mulatta) by immunohistochemistry and directly compare it to human tissues. There are considerable differences in the myenteric plexus along different segments of the monkey GI tract. While acetylcholine neurons make up the majority of myenteric neurons in the stomach (70%), they are a minority in the rectum (47%). Conversely, only 22% of gastric myenteric neurons express nitric oxide synthase (NOS) compared to 52% in the rectum. Vasoactive intestinal peptide (VIP) is more prominent in the stomach (37%) versus the rest of the GI tract (10%), and catecholamine neurons are rare (1%). There is significant coexpression of NOS and VIP in myenteric neurons that is more prominent in the proximal GI tract. Taken as a whole, these data provide insight into the neurochemical anatomy underlying GI motility. While overall similarity to other mammalian species is clear, there are some notable differences between the ENS of rhesus monkeys, humans, and other species that will be important to take into account when evaluating models of human diseases in animals.
Parkinson’s disease (PD) is a progressive neurodegenerative disorder that is characterized by the loss of dopamine neurons in the substantia nigra pars compacta, culminating in severe motor symptoms, including: resting tremor, rigidity, bradykinesia, and postural instability. In addition to motor deficits, there are a variety of non-motor symptoms associated with PD. These symptoms generally precede the onset of motor symptoms, sometimes by years, and include anosmia, problems with gastrointestinal motility, sleep disturbances, sympathetic denervation, anxiety, and depression. Previously, we have shown that mice with a 95% genetic reduction in vesicular monoamine transporter expression (VMAT2-deficient, VMAT2 LO) display progressive loss of striatal dopamine, L-DOPA responsive motor deficits, α-synuclein accumulation, and nigral dopaminergic cell loss. We hypothesized that since these animals exhibit deficits in other monoamine systems (norepinephrine, serotonin), which are known to regulate some of these behaviors that the VMAT2-deficient mice may display some of the non-motor symptoms associated with PD. Here we report that the VMAT2-deficient mice demonstrate progressive deficits in olfactory discrimination, delayed gastric emptying, altered sleep latency, anxiety-like behavior, and age-dependent depressive behavior. These results suggest that the VMAT2-deficient mice may be a useful model of the non-motor symptoms of PD. Furthermore, monoamine dysfunction may contribute to many of the non-motor symptoms of PD and interventions aimed at restoring monoamine function may be beneficial in treating the disease.
Parkinson's disease (PD) is a common neurodegenerative movement disorder afflicting millions of people in the United States. The advent of transgenic technologies has contributed to the development of several new mouse models, many of which recapitulate some aspects of the disease; however, no model has been demonstrated to faithfully reproduce the full constellation of symptoms seen in human PD. This may be due in part to the narrow focus on the dopamine-mediated motor deficits. As current research continues to unmask PD as a multi-system disorder, animal models should similarly evolve to include the non-motor features of the disease. This requires that typically cited behavioral test batteries be expanded. The major non-motor symptoms observed in PD patients include hyposmia, sleep disturbances, gastrointestinal dysfunction, autonomic dysfunction, anxiety, depression, and cognitive decline. Mouse behavioral tests exist for all of these symptoms and while some models have begun to be reassessed for the prevalence of this broader behavioral phenotype, the majority has not. Moreover, all behavioral paradigms should be tested for their responsiveness to L-DOPA so these data can be compared to patient response and help elucidate which symptoms are likely not dopamine-mediated. Here, we suggest an extensive, yet feasible, battery of behavioral tests for mouse models of PD aimed to better assess both non-motor and motor deficits associated with the disease.
An 80-year-old white woman with a history of hyperthyroidism treated with radioactive iodine ablation, gastroesophageal reflux disease complicated by Barrett esophagus, osteoarthritis, breast cancer status post-bilateral mastectomy, and diverticulosis presented with severe left-sided headache and diplopia. Three weeks prior to presentation, she developed a sharp pain located over the left temporal, parietal, and occipital regions. It was associated with exquisite scalp tenderness. Over the next few days, the pain progressed, involving the left side of the face, including the periorbital region. There was no radiation of the pain, and she had little relief with over-the-counter acetaminophen. She also experienced earache, sore throat, and left jaw pain with mastication.
Background and Purpose:
Neurology residency training programs have been profoundly impacted by recent changes in resident duty hours, workloads, and supervisory requirements. In response, many programs have adopted a night float coverage system to minimize the requirements for overnight call. The majority involves residents working a block of night shifts in what is typically a service-oriented rotation. Recently, concerns have arisen regarding the impact of this design on resident education and patient care. We have developed a novel on-site nighttime neurohospitalist model for the explicit purpose of steepening the initial learning curve for neurology residents in an effort to rapidly improve their neurological skills and, in conjunction, overnight patient care. We surveyed residents after the initiation of this system to assess their perception of the impact of direct overnight supervision on education and patient care.
Methods:
As part of ongoing quality improvement efforts, surveys were administered to neurology house staff at a tertiary academic medical center after they had completed service on the night float rotation both with and without an attending in the hospital using a retrospective pre/postdesign.
Results:
There was a robust positive impact on resident’s perception of overall quality, educational value, and clinical quality on the night float rotation with an attending on-site. Despite an overall perception that their autonomy was maintained, residents believed barriers to contact the attending were lower, and attending interaction during critical decision making was more frequent.
Conclusions:
Direct overnight supervision by a neurohospitalist enhances the educational value and care quality on overnight resident rotations.
Dysfunction of dopamine neurons has been implicated in several neuropsychiatric disorders, including Parkinson's disease, addiction, bipolar disorder and depression. Recent elucidation of gene expression profiles in dopamine neuron subpopulations has shed light on the function of different groups of dopamine neurons in the CNS and on their dysfunction in disease states. In particular, concerted differences in gene expression appear to underlie the unique properties of distinct dopamine neurons. Specifically, dopamine neurons in the substantia nigra (SN), which are prone to degenerate in Parkinson's disease, express high levels of transcripts related to energy metabolism, mitochondria and phosphate signalling pathways. In contrast, ventral tegmental area (VTA) dopamine neurons prominently express genes related to synaptic plasticity and neuropeptides, suggesting intriguing mechanisms for the involvement of VTA dysfunction in addiction and mood disorders. As new functions of dopaminergic neurotransmission become clearer, continued exploration of the transcriptional neuroanatomy of these unique neurons will be vital for producing targeted, selective, and effective therapeutic agents.