Neuronal Migration: How Do You Build a Brain?

Senior biology major Alex Burkard is working in the Walsh Neurodevelopment Laboratory at VCU to help answer the question, ‘How do you build a brain?’ Burkard is researching neuronal migration in Zebrafish and how cellular polarity affects hindbrain development

Lead Exposure in Children through Water and Soil

Lead is a metal which has the ability to spread in the earth’s crust and has corrosive property. It is a naturally occurring metal which is soft in nature. Lead exposure in children is through various pathways and the major concentrated sources are the soil and drinking water. Children are most susceptible to lead exposure is due to their growing/developing bodies which are very sensitive to lead. Lead poisoning in children is a preventable environmental disease affecting many children around the world. This paper discusses how soil and water plays a major role in lead exposure to children’s routine life. The adverse effects of lead poisoning range widely from delayed to severe health outcomes. According to the Center for Disease Control and Prevention (CDC) the blood lead levels should be no higher than 5µg/dl, which is considered as the new reference value. The epidemiological studies in the article details some statistical evidence that how children are affected by lead exposure through soil and water. Animal behavioral studies are mentioned in order to compare the toxic levels to humans. Even though there has been decline in the blood lead levels in children from 1970’s, very small amounts of blood lead can also result in various health outcomes. These blood lead levels in children are due to the lead based paints in old houses and the service lines made by lead and lead solder. Due to some regulatory interventions by the state and federal agencies the developed countries have reduced the lead exposure to an extent, but the developing countries are still at greatest concern in childhood lead poisoning

Anxiety Reactivity in Monozygotic Twins Discordant for Major Depression

Transient anxiety is a healthy response to stress. However, constant anxiety elicits negative responses and threatens an individual’s day-to-day living. The onset of anxiety disorders excluding specific phobias is often childhood to late adolescence or early adulthood. Though depression is characterized as a low-energy state unlike anxiety, there is a high concordance between anxiety and depression. “Nearly one-half of those diagnosed with depression are also diagnosed with an anxiety disorder” (“Facts and Statistics”). There are two goals of the study: 1. To compare the individual response levels between monozygotic (MZ) twins discordant for major depressive disorder (MDD) during an anxiety-provoking task. 2. To evaluate the relationship between self-report measures and physiological responses in adolescent MZ twins discordant for MDD. To identify how physiological responses vary between MZ twins discordant for major depression during a resting baseline and the 7.5% carbon dioxide (CO2) breathing challenge task. The data was analyzed using multiple statistical methods including paired samples t-test and correlational models. We expected that MDD affected twins would self-report greater distress in response to an anxiety-provoking laboratory challenge and exhibit reduced physiological arousal. MDD affected twins demonstrated a somewhat reduced skin conductance response during the anxiety provoking task, suggesting blunted physiological response, which is consistent with other biological markers such as cortisol. There was a significant increase in sympathetic-vagal heart variability rate during the physiological baseline for the MDD affected twins. Although we did not observe any statistically significant differences for SUDS ratings assessed during baseline or inhalation of 7.5% CO2 enriched air, MDD affected twins reported higher levels of distress during the recovery period compared to their MDD unaffected co-twin. The results will shed light on the lasting impact of major depression on physiologic and subjective measures during rest and the biological challenge.https://scholarscompass.vcu.edu/uresposters/1160/thumbnail.jp

Subjective Measures of MZ and DZ Twins during Anxiety-Provoking Tasks

Temporary anxiety is a healthy response to stress; however, continuous anxiety can threaten an individual’s day-to-day living by eliciting negative responses. In the study, monozygotic 84 (MZ) and 153 dizygotic (DZ) adolescent twins pairs, ages 15 to 20 years, participated in anxiety-provoking tasks and subjective experiences of anxiety were measured using subjective units of distress (SUDS). The twin participants were recruited through the Mid-Atlantic Twin Registry (MATR) at Virginia Commonwealth University. The twins participated in a carbon dioxide (CO2) breathing task and a trier social stress task (TSST). The study aims were to evaluate the relationship between anxiety-provoking tasks and subjective experiences of anxiety in MZ and DZ adolescent twins and to compare SUDS ratings in the CO2 task to SUDS ratings in the TSST to determine which task produces greater anxiety. The data was analyzed using correlational models. MZ twins reported more similar SUDS in both the CO2 task and trier task than the DZ twins, however, not at significant values. The mean SUDS ratings for MZ twins and DZ twins were higher in the trier task than the CO2 task, suggesting that the trier task was a better inducer of anxiety than the CO2 task. The goal of the research was to characterize etiological pathways involved in the development of internalizing disorders and to set the stage for advancement of effective intervention and prevention programs, specifically by determining the relationship between SUDS ratings and anxiety-provoking tasks in MZ and DZ twins. Further study is needed to evaluate the heritability of anxiety response.https://scholarscompass.vcu.edu/uresposters/1213/thumbnail.jp

Organophosphates in Chlorpyrifos Insecticide: Neurobehavioral Development of Children in Agricultural Communities

The chemicals found in fertilizers and pesticides are known to adversely affect the human nervous system even at low levels of exposure. Neither the agricultural industry nor the EPA can deny scientific findings regarding the toxic qualities of organophosphates in the insecticide chlorpyrifos, but that does not deter pesticide manufacturers from selling harmful products. In fact, Dow AgroSciences, a pesticide company, states on its website that, “Insecticides, such as chlorpyrifos, provide important protection for our food supply and thus safeguard farm and consumer economy.” To understand the health risks associated with pesticide exposure, I studied the influence of organophosphates in the insecticide chlorpyrifos on children living in agricultural communities, primarily in Salinas Valley, California. I performed the review by analyzing a variety of articles and academic sources that focused on organophosphate exposure and child neurobehavioral functioning. The findings indicate that organophosphates found in the insecticide chlorpyrifos block the enzyme acetylcholinesterase and initiate the accumulation of the neurotransmitter acetylcholine, leading to impairments in attention and cognition. Farm children exposed to the chemicals via the mother during gestation period or who are exposed through inhalation or physical contact may be at higher risks for ADHD and autism than reference children who are typically only exposed to organophosphates through diet. Further study is needed to understand gender-based effects following organophosphate exposure. It is only through understanding the damaging effects of chemicals in pesticides that policies can be constructed to effectively reduce pesticide application and encourage alternatives of crop rotation, intercropping, crop diversity, and the use of pests to fight pests in the agricultural society.https://scholarscompass.vcu.edu/uresposters/1162/thumbnail.jp

Structural characterization of GASDALIE Fc bound to the activating Fc receptor FcγRIIIa

The Fc region of Immunoglobulin G (IgG) initiates inflammatory responses such as antibody-dependent cell-mediated cytotoxicity (ADCC) through binding to activating Fc receptors (FcγRI, FcγRIIa, FcγRIIIa). These receptors are expressed on the surface of immune cells including macrophages, dendritic cells, and natural killer cells. An inhibitory receptor, FcγRIIb, is expressed on macrophages and other myeloid leukocytes simultaneously with the activating receptor FcγRIIa, thereby setting a threshold for cell activation. The affinity of IgG Fc for binding activating Fc receptors depends on IgG subclass and the composition of N-linked glycans attached to a conserved asparagine in the Fc C_H2 domain. For example, Fc regions with afucosylated glycans bind more tightly to FcγRIIIa than fucosylated Fc, and afucosylated Fcs exhibit enhanced ADCC activity in vivo and in vitro. Enhanced pro-inflammatory responses have also been seen for Fc regions with amino acid substitutions. GASDALIE Fc is an Fc mutant (G236A/S239D/A330L/I332E) that exhibits a higher affinity for FcγRIIIa and increased effector functions in vivo compared to wild-type Fc. To explore its altered functions, we compared the affinities of GASDALIE and wild-type Fc for activating and inhibitory FcγRs. We also determined the crystal structure of GASDALIE Fc alone and bound to FcγRIIIa. The overall structure of GASDALIE Fc alone was similar to wild-type Fc structures, however, increased electrostatic interactions in the GASDALIE Fc:FcγRIIIa interface compared with other Fc:FcγR structures suggest a mechanism for the increased affinity of GASDALIE Fc for FcγRIIIa

Granular cell ameloblastoma of jaw: report of a case with an emphasis on its characterization

Ameloblastoma is a neoplasm of odontogenic epithelium, especially of enamel organ-type tissue that has not under gone differentiation to the point of hard tissue formation. It accounts for approximately 10% of all tumors originating from gnathic bones. It exhibits diverse microscopic patterns which occurs either singly or in combination with other patterns. Granular cell ameloblastoma is a rare condition, accounting for 3.5% of all ameloblastoma cases that shows marked transformation in the cytoplasm of tumor cells, which are usually stellate reticulum like cells. The transformed cells possess very coarse, granular, eosinophilic cytoplasm. The 'granular change' is thought to be due to a dysfunctional status of neoplastic cells, and the pathogenesis of this tumour seems to be age-related. Ultrastructural, histochemical, and immunohitochemical studies have revealed that cytoplasmic granularity is caused by overload; however the mechanism ivolved remains poorly understood. This article describes a case of granular cell variant of ameloblastoma affecting a 55-year old femal