Grettel J. Zamora-Berridi

Neurosphere Assays: Growth Factors and Hormone Differences in Tumor and Nontumor Studies

The “no new neuron” dogma that the brain is quiescent throughout adult life has been challenged by the discovery of cells with stem cell‐like qualities of self‐renewal and multipotency in the subventricular zone of the lateral ventricles and the dentate gyrus of the hippocampus in adults. This self‐renewing capacity also makes these neural stem cells a possible source of brain tumors, which was supported by the discovery of self‐sustaining brain tumor stem‐like cells in cancers such as glioblastoma multiforme. Neurosphere assays are the standard for studying these stem‐like cells in both normal and cancer tissues. Despite the importance of these assays, there is no standardized protocol to allow for a comparison of results because several studies use different growth factors and hormones at different concentrations. The primary objective of this study is to review the literature for both nontumor and tumor studies to assess their respective neurosphere assay components. We found significant variation in assay components, namely hormones and growth factors, as well as their respective concentrations. This illustrates the need for a standardized protocol to allow proper comparison among studies and a better assessment of the effects of different factors.

Cytoarchitecture of the lateral ganglionic eminence and rostral extension of the lateral ventricle in the human fetal brain.

The fetal development of the anterior subventricular zone (SVZ) involves the transformation of radial glia into neural stem cells, in addition to the migration of neuroblasts from the SVZ towards different regions in the brain. In adult rodents this migration from the anterior SVZ is restricted to the olfactory bulb following a rostral migratory stream (RMS) formed by chains of migratory neuroblasts. Similar to rodents, an RMS has been suggested in the adult human brain, where the SVZ remains as an active proliferative region. Nevertheless, a human fetal RMS has not been described and the presence of migratory neuroblasts in the adult remains controversial. Here we describe the cytoarchitecture of the human SVZ at the lateral ganglionic eminence late in the second trimester of development (23–24 weeks postconception). Cell organization in this region is heterogeneous along the ventricular wall, with GFAP‐positive cells aligned to the ventricle. These cells coexpress markers for radial glia like GFAPδ, nestin, and vimentin. We also show the presence of abundant migratory neuroblasts in the anterior horn SVZ forming structures here denominated cell throngs. Interestingly, a ventral extension of the lateral ventricle suggests the presence of a putative RMS. Nevertheless, in the olfactory bulb neuroblast throngs or chain‐like structures were not observed. The lack of these structures closer to the olfactory bulb could indicate a destination for the migratory neuroblasts outside the olfactory bulb in the human brain. J. Comp. Neurol. 519:1165–1180, 2011.

Neuromuscular effects of G93A-SOD1 expression in zebrafish

BackgroundAmyotrophic lateral sclerosis (ALS) is a fatal disorder involving the degeneration and loss of motor neurons. The mechanisms of motor neuron loss in ALS are unknown and there are no effective treatments. Defects in the distal axon and at the neuromuscular junction are early events in the disease course, and zebrafish provide a promising in vivo system to examine cellular mechanisms and treatments for these events in ALS pathogenesis.ResultsWe demonstrate that transient genetic manipulation of zebrafish to express G93A-SOD1, a mutation associated with familial ALS, results in early defects in motor neuron outgrowth and axonal branching. This is consistent with previous reports on motor neuron axonal defects associated with familial ALS genes following knockdown or mutant protein overexpression. We also demonstrate that upregulation of growth factor signaling is capable of rescuing these early defects, validating the potential of the model for therapeutic discovery. We generated stable transgenic zebrafish lines expressing G93A-SOD1 to further characterize the consequences of G93A-SOD1 expression on neuromuscular pathology and disease progression. Behavioral monitoring reveals evidence of motor dysfunction and decreased activity in transgenic ALS zebrafish. Examination of neuromuscular and neuronal pathology throughout the disease course reveals a loss of neuromuscular junctions and alterations in motor neuron innervations patterns with disease progression. Finally, motor neuron cell loss is evident later in the disease.ConclusionsThis sequence of events reflects the stepwise mechanisms of degeneration in ALS, and provides a novel model for mechanistic discovery and therapeutic development for neuromuscular degeneration in ALS.

Intra-Operatively Obtained Human Tissue: Protocols and Techniques for the Study of Neural Stem Cells

The discoveries of neural (NSCs) and brain tumor stem cells (BTSCs) in the adult human brain and in brain tumors, respectively, have led to a new era in neuroscience research. These cells represent novel approaches to studying normal phenomena such as memory and learning, as well as pathological conditions such as Parkinsons disease, stroke, and brain tumors. This new paradigm stresses the importance of understanding how these cells behave in vitro and in vivo. It also stresses the need to use human-derived tissue to study human disease because animal models may not necessarily accurately replicate the processes that occur in humans. An important, but often underused, source of human tissue and, consequently, both NSCs and BTSCs, is the operating room. This study describes in detail both current and newly developed laboratory techniques, which in our experience are used to process and study human NSCs and BTSCs from tissue obtained directly from the operating room.

Postoperative outcomes following closed head injury and craniotomy for evacuation of hematoma in patients older than 80 years

OBJECT Advances in the management of trauma-induced intracranial hematomas and hemorrhage (epidural, subdural, and intraparenchymal hemorrhage) have improved survival in these conditions over the last several decades. However, there is a paucity of research investigating the relation between patient age and outcomes of surgical treatment for these conditions. In this study, the authors examined the relation between patient age over 80 years and postoperative outcomes following closed head injury and craniotomy for intracranial hemorrhage. METHODS A consecutive population of patients undergoing emergent craniotomy for evacuation of intracranial hematoma following closed head trauma between 2006 and 2009 was identified. Using multivariable logistic regression models, the authors assessed the relation between age (> 80 vs ≤ 80 years) and postoperative complications, intensive care unit stay, hospital stay, morbidity, and mortality. RESULTS Of 103 patients, 27 were older than 80 years and 76 patients were 80 years of age or younger. Older age was associated with longer length of hospital stay (p = 0.014), a higher rate of complications (OR 5.74, 95% CI 1.29-25.34), and a higher likelihood of requiring rehabilitation (OR 3.28, 95% CI 1.13-9.74). However, there were no statistically significant differences between the age groups in 30-day mortality or ability to recover to functional baseline status. CONCLUSIONS The findings suggest that in comparison with younger patients, patients over 80 years of age may be similarly able to return to preinjury functional baselines but may require increased postoperative medical attention in the forms of rehabilitation and longer hospital stays. Prospective studies concerned with the relation between older age, perioperative parameters, and postoperative outcomes following craniotomy for intracranial hemorrhage are needed. Nonetheless, the findings of this study may allow for more informed decisions with respect to the care of elderly patients with intracranial hemorrhage.

Insurance Status and Inequalities in Outcomes After Neurosurgery

OBJECTIVE Little is known about socioeconomic differences in postoperative outcomes after neurosurgery. We assessed the relation between insurance status and postoperative complication risk, neurosurgical intensive care unit stay, and hospital stay after neurosurgery. METHODS We collected data on 918 consecutive craniotomy or spine-related neurosurgical cases in patients at least 18 years of age at the University of Michigan Hospitals after April 2006. Bivariate χ(2) tests and analysis of variance were used to assess bivariate relations, and multivariable logistic regression models and analysis of covariance were used to adjust for potential confounders. RESULTS A total of 11.2% of privately insured patients, 23.6% of Medicare patients, 25.8% of Medicaid patients, and 27.3% of uninsured patients suffered complications within 30 days of surgery (P < 0.001). In adjusted models, odds of postoperative complications among Medicare (odds ratio [OR] = 2.1, 95% confidence interval [CI] 1.3-3.3), Medicaid (OR = 3.1, 95% CI 1.5-6.1), and uninsured patients (OR = 3.6. 95% CI 1.3-10.3) were higher than among privately insured patients. By analysis of covariance, only Medicaid patients had significantly longer intensive care unit (P = 0.040) and hospital stays (P = 0.028) than privately insured patients. CONCLUSIONS Our findings suggest important socioeconomic disparities in outcomes after neurosurgical intervention. Access to postoperative outpatient care may mediate our findings.

Correlation of acute phase inflammatory and oxidative markers with long-term cognitive impairment in sepsis survivors rats.

ABSTRACT Oxidative damage and inflammation occur early in the brain after sepsis and are resolved when long-term cognitive impairment occurs. There is no information of a direct relation between acute levels of brain inflammation and oxidative damage and long-term cognitive deficits. We hypothesized that higher levels of early oxidative damage and inflammation are followed by long-term cognitive deficits, and this is related to a decrease in the levels of brain-derived neurotropic factor (BDNF). Wistar rats were subjected to sham operation or cecal ligation and perforation and the cerebrospinal fluid (CSF) was obtained 6 and 24 h after the determination of thiobarbituric acid–reactive species, interleukin 1 (IL-1), IL-10, and tumor necrosis factor &agr; (TNF-&agr;). Animals were followed until 30 days after surgery and were subjected to the step-down inhibitory avoidance (IA) task, and the hippocampus levels of BDNF were determined. At 6 h, higher CSF levels of thiobarbituric acid–reactive species and TNF-&agr; were observed in septic animals that had a better performance in the IA task and presented higher BDNF levels in the hippocampus. At 24 h, higher CSF levels of IL-1&bgr; and TNF-&agr; were observed in septic animals that had a worse performance in the IA task, and this was associated with lower BDNF levels. The persistence of brain inflammation during the acute phase of sepsis is associated with long-term hippocampus levels of BDNF and memory impairment in sepsis survivors.

Sex disparities in postoperative outcomes after neurosurgical intervention: findings from the UMEND project.

BACKGROUND: Little is known about the relationship between sex and the risk of complications after neurosurgical intervention. Improved understanding of this relationship may assist clinicians in advising patients of the risks and benefits of neurosurgical intervention and managing their patients after surgery. OBJECTIVE: To determine the independent relationship between sex and morbidity after neurosurgical intervention. METHODS: Data were collected for 918 neurosurgical cases at the University of Michigan Hospitals. Bivariate &khgr;2 tests and analysis of variance were used to assess relationships between sex, demographics, case type, medical comorbidities, postoperative complication risk, and postoperative hospital and intensive care unit stay. We fit a multivariable logistic regression model of 30-day complication risk by sex adjusted for potential confounders and used multifactor analysis of variance to assess the relationship between sex and hospital as well as intensive care unit stay, adjusted for potential confounders. RESULTS: The percentages of patients experiencing complications within 30 days of surgery were 20.3% for male and 11.3% for female patients. In multivariable regression models, male sex predicted postoperative complications compared with female sex (odds ratio: 2.0, 95% confidence interval: 1.4-3.0). By multifactor analysis of variance, male sex was associated with longer hospital stay (P < .01), but was not associated with neurosurgical intensive care unit stay. CONCLUSION: Our findings suggest male sex is an independent predictor of postoperative complication risk and increased hospital stay after neurosurgical intervention. This finding may be used clinically to help identify those patients at increased risk of a complicated recovery. Future research might consider mechanisms relating sex and postoperative outcomes.

Santiago Ramón y Cajal and Harvey Cushing: Two Forefathers of Neuroscience and Neurosurgery

OBJECTIVE To summarize the extraordinary accomplishments, and the commonalities, between Santiago Ramon y Cajal and Harvey Williams Cushing. METHODS Existing literature describing the lives and achievements of Ramón y Cajal and Cushing, as well as personal communication, and the surgical records of the Johns Hopkins Hospital, from 1896 to 1912, were reviewed. RESULTS Both Ramón y Cajal and Cushing were men of unusually broad interests and talents, and these shared characteristics undoubtedly influenced the career paths and scientific investigations they pursued. Although Santiago Ramón y Cajal and Harvey Williams Cushing never directly interacted, the links between them can be traced through some of their disciples, including Pío del Río Hortega, Wilder Penfield, and Percival Bailey. CONCLUSIONS Ramón y Cajal and Cushing are widely considered the forefathers of neuroscience and neurosurgery, respectively, and their discoveries have made lasting impressions on both the scientific and medical communities.