Origins and Proliferative States of Human Oligodendrocyte Precursor Cells.

Human cerebral cortex size and complexity has increased greatly during evolution. While increased progenitor diversity and enhanced proliferative potential play important roles in human neurogenesis and gray matter expansion, the mechanisms of human oligodendrogenesis and white matter expansion remain largely unknown. Here, we identify EGFR-expressing "Pre-OPCs" that originate from outer radial glial cells (oRGs) and undergo mitotic somal translocation (MST) during division. oRG-derived Pre-OPCs provide an additional source of human cortical oligodendrocyte precursor cells (OPCs) and define a lineage trajectory. We further show that human OPCs undergo consecutive symmetric divisions to exponentially increase the progenitor pool size. Additionally, we find that the OPC-enriched gene, PCDH15, mediates daughter cell repulsion and facilitates proliferation. These findings indicate properties of OPC derivation, proliferation, and dispersion important for human white matter expansion and myelination.

Nonimmune hydrops fetalis: identifying the underlying genetic etiology.

PURPOSE: Numerous etiologies may lead to nonimmune hydrops fetalis (NIHF), and the underlying cause often remains unclear. We aimed to determine the proportion of NIHF cases in which the etiology was clearly determined in a large, contemporary, and diverse cohort, as well as to describe the etiologies with a focus on genetic causes. METHODS: Retrospective review of NIHF cases between 2015 and 2017 from the five University of California Fetal-Maternal Consortium sites. Singleton pregnancies with prenatally diagnosed NIHF were included, and cases with maternal alloimmunization were excluded. Cases were categorized as being of confirmed, suspected, or unknown etiology. RESULTS: Sixty-five NIHF cases were identified. Forty-six percent (30/65) remained of unknown etiology, while 9.2% (6/65) had a suspected etiology and 44.6% (29/65) were of confirmed etiology. Among confirmed cases, 11 resulted from aneuploidy; 7 from fetal structural anomalies; 2 each from fetal arrhythmia, Noonan syndrome, and generalized lymphatic dysplasia; and 1 each from arthrogryposis, parvovirus, neonatal alloimmune thrombocytopenia, fetal goiter, and Kasabach-Merritt syndrome. CONCLUSION: In this contemporary, multicenter study, the cause of prenatally diagnosed NIHF was confirmed in only 44% of cases, and a genetic etiology was found in only 25% of those that received standard of care genetic testing.

Neonatal Seizures.

Neonatal seizures are common among patients with acute brain injury or critical illness and can be difficult to diagnose and treat. The most common etiology of neonatal seizures is hypoxic-ischemic encephalopathy, with other common causes including ischemic stroke and intracranial hemorrhage. Neonatal clinicians can use a standardized approach to patients with suspected or confirmed neonatal seizures that entails laboratory testing, neuromonitoring, and brain imaging. The primary goals of management of neonatal seizures are to identify the underlying cause, correct it if possible, and prevent further brain injury. This article reviews recent evidence-based guidelines for the treatment of neonatal seizures and discusses the long-term outcomes of patients with neonatal seizures.

Comorbidities and Late Outcomes in Neonatal Pulmonary Hypertension.

Long-term outcomes of persistent pulmonary hypertension of newborn (PPHN) depend on disease severity, duration of ventilation, and associated anomalies. Congenital diaphragmatic hernia survivors may have respiratory morbidities and developmental delay. The presence of PPHN is associated with increased mortality in hypoxic-ischemic encephalopathy, though the effects on neurodevelopment are less clear. Preterm infants can develop pulmonary hypertension (PH) early in the postnatal course or later in the setting of bronchopulmonary dysplasia (BPD). BPD-PH is associated with higher mortality, particularly within the first year. Evidence suggests that both early and late PH in preterm infants are associated with neurodevelopmental impairment.

The Impact of Telemedicine on Transfer Rates of Newborns at Rural Community Hospitals.

BACKGROUND AND OBJECTIVE: Telemedicine may have the ability to reduce avoidable transfers by allowing remote specialists the opportunity to more effectively assess patients during consultations. In this study, we examined whether telemedicine consultations were associated with reduced transfer rates compared to telephone consultations among a cohort of term and late preterm newborns. We hypothesized that neonatologist consultations conducted over telemedicine would result in fewer interfacility transfers than consultations conducted over telephone. METHODS: We collected data on all newborns who received a neonatal telemedicine or telephone consultation at 6 rural hospitals in northern and central California between August 2014 and June 2018. We used adjusted analyses to compare transfer rates between telemedicine and telephone cohorts. RESULTS: A total of 317 patients were included in the analysis; 89 (28.1%) of these patients received a telemedicine consultation and 228 (71.9%) received a telephone consultation only. The overall transfer rate was 77.0%. Patient consultations conducted using telemedicine were significantly less likely to result in a transfer than patient consultations conducted using the telephone (64.0% vs 82.0%, P = .001). After controlling for 5-minute Apgar score, birthweight, gestational age, site of consultation, and Transport Risk Index of Physiologic Stability score, the odds of transfer for telemedicine consultations was 0.48 (95% confidence interval: 0.26, 0.90, P = .02). CONCLUSIONS: Our findings suggest that telemedicine may have the potential to reduce potentially avoidable transfers of term and late preterm newborns. Future research on potentially avoidable transfers and patient outcomes is needed to better understand the ways in which telemedicine affects clinical decision-making.

Pbx3 is required for normal locomotion and dorsal horn development.

The transcription cofactor Pbx3 is critical for the function of hindbrain circuits controlling respiration in mammals, but the perinatal lethality caused by constitutively null mutations has hampered investigation of other roles it may play in neural development and function. Here we report that the conditional loss of Pbx3 function in most tissues caudal to the hindbrain resulted in progressive deficits of posture, locomotion, and sensation that became apparent during adolescence. In adult mutants, the size of the dorsal horn of the spinal cord and the numbers of calbindin-, PKC-gamma, and calretinin-expressing neurons in laminae I-III were markedly reduced, but the ventral cord and peripheral nervous system appeared normal. In the embryonic dorsal horn, Pbx3 expression was restricted to a subset of glutamatergic neurons, but its absence did not affect the initial balance of excitatory and inhibitory interneuron phenotypes. By embryonic day 15 a subset of Meis(+) glutamatergic neurons assumed abnormally superficial positions and the number of calbindin(+) neurons was increased three-fold in the mutants. Loss of Pbx3 function thus leads to the incorrect specification of some glutamatergic neurons in the dorsal horn and alters the integration of peripheral sensation into the spinal circuitry regulating locomotion.

Amyloid-beta, tau alterations and mitochondrial dysfunction in Alzheimer disease: the chickens or the eggs?

Alzheimer disease (AD) is defined pathologically and diagnostically defined by amyloid-beta senile plaques and neurofibrillary tangles (NFT) composed of tau. From the time of their original description nearly a century ago, a major focus has been to understand the role that these lesions play in the pathogenesis of the disease. The majority favors the notion that these lesions cause the disease and therefore attempts at therapeutic intervention are focused on preventing lesions formation. However, this rationale may be misguided since new evidence from our laboratories and others suggest that the lesions not only occur as a by-product of the fundamental disease process but also that they may be protective.

The role of iron and copper in the aetiology of neurodegenerative disorders: therapeutic implications.

Abnormalities in the metabolism of the transition metals iron and copper have been demonstrated to play a crucial role in the pathogenesis of various neurodegenerative diseases. Metal homeostasis as it pertains to alterations in brain function in neurodegenerative diseases is reviewed in this article in depth. While there is documented evidence for alterations in the homeostasis, redox-activity and localisation of transition metals, it is also important to realise that alterations in specific copper- and iron-containing metalloenzymes appear to play a crucial role in the neurodegenerative process. These changes provide the opportunity to identify pathways where modification of the disease process can occur, potentially offering opportunities for clinical intervention. As understanding of disease aetiology evolves, so do the tools with which diseases are treated. In this article, we examine not only the possible mechanism of disease but also how pharmaceuticals may intervene, from direct and indirect antioxidant therapy to strategies involving gene therapy.

The state versus amyloid-beta: the trial of the most wanted criminal in Alzheimer disease.

Investigators studying the primary culprit responsible for Alzheimer disease have, for the past two decades, primarily focused on amyloid-beta (Abeta). Here, we put Abeta on trial and review evidence amassed by the prosecution that implicate Abeta and also consider arguments and evidence gathered by the defense team who are convinced of the innocence of their client. As in all trials, the arguments provided by the prosecution and defense revolve around the same evidence, with opposing interpretations. Below, we present a brief synopsis of the trial for you, the jury, to decide the verdict. Amyloid-beta: guilty or not-guilty?