ABSTRACT
Knowledge of embryology is foundational for understanding normal anatomy and birth defects, yet, embryology is a notoriously difficult subject for medical students. Embryonic lateral folding in particular is one of the most challenging concepts in embryology. Highly effective teaching methods that promote active engagement with dynamic, three-dimensional models may be helpful for teaching this content. The aim of this study was to determine whether a hands-on modeling activity utilizing premade crocheted pieces constructed from durable, inexpensive yarn helped medical students enrolled in a pre-matriculation course to understand embryonic lateral folding. Change in knowledge was assessed using a pre-post design. Students also completed subjective evaluations regarding their satisfaction with the activity. Quiz scores in means (±SD) increased from 62.7 (±24.1) % before the activity to 77.0 (±17.1) % after the activity (P = 0.0495, two-tailed paired t test; d = 0.68). Generally, students reported that the activity was helpful and enjoyable, and the model pieces were easy to manipulate. These promising results suggest that hands-on activities with dynamic, three-dimensional models constitute an effective method for teaching embryology.
Subject(s)
Anatomy , Education, Medical, Undergraduate , Students, Medical , Anatomy/education , Educational Measurement , Humans , TeachingABSTRACT
Methamphetamine (MA) is a potent, highly addictive psychostimulant abused by millions of people worldwide. MA induces neurotoxicity, damaging striatal dopaminergic terminals, and neuroinflammation, with striatal glial activation leading to pro-inflammatory cytokine and reactive oxygen species production. It is unclear whether MA-induced neuroinflammation contributes to MA-induced neurotoxicity. In the current study, we examined the linkage between the time course and dose response of MA-induced neurotoxicity and neuroinflammation. Adult male mice underwent a binge dosing regimen of four injections given every 2h with doses of 2, 4, 6, or 8 mg/kg MA per injection, and were sacrificed after 1, 3, 7, or 14 days. Binge MA treatment dose-dependently caused hyperthermia and induced hypoactivity after one day, though activity returned to control levels within one week. Striatal dopamine (DA) was diminished one day after treatment with at least 4 mg/kg MA, while DA turnover rates peaked after seven days. Although striatal tyrosine hydroxylase and DA transporter levels were also decreased one day after treatment with at least 4 mg/kg MA, they trended toward recovery by day 14. All doses of MA activated striatal glia within one day. While astrocyte activation persisted, microglial activation was attenuated over the two weeks of the study. These findings help clarify the relationship between MA-induced neuroinflammation and neurotoxicity, particularly regarding their temporal and dose-specific dynamics.
Subject(s)
Calcium-Binding Proteins/metabolism , Central Nervous System Stimulants/toxicity , Encephalitis/chemically induced , Methamphetamine/toxicity , Microfilament Proteins/metabolism , Neurotoxicity Syndromes/etiology , Animals , Biogenic Monoamines/metabolism , Body Temperature/drug effects , Corpus Striatum/drug effects , Corpus Striatum/metabolism , Disease Models, Animal , Dopamine Plasma Membrane Transport Proteins/metabolism , Dose-Response Relationship, Drug , Electrochemical Techniques , Encephalitis/physiopathology , Glial Fibrillary Acidic Protein/metabolism , Male , Mice , Mice, Inbred C57BL , Motor Activity/drug effects , Neurotoxicity Syndromes/physiopathology , Time Factors , Tyrosine 3-Monooxygenase/metabolismABSTRACT
Attempts to determine the influence of testicular hormones on learning and memory in males have yielded contradictory results. The present studies examined whether testicular hormones are important for maximal levels of spatial memory in young adult male rats. To minimize any effect of stress, we used the Object Location Task which is a spatial working memory task that does not involve food or water deprivation or aversive stimuli for motivation. In Experiment 1 sham gonadectomized male rats demonstrated robust spatial memory, but gonadectomized males showed diminished spatial memory. In Experiment 2 subcutaneous testosterone (T) capsules restored spatial memory performance in gonadectomized male rats, while rats with blank capsules demonstrated compromised spatial memory. In Experiment 3, gonadectomized male rats implanted with blank capsules again showed compromised spatial memory, while those with T, dihydrotestosterone (DHT), or estradiol (E) capsules demonstrated robust spatial memory, indicating that T's effects may be mediated by its conversion to E or to DHT. Gonadectomized male rats injected with Antide, a gonadotropin-releasing hormone receptor antagonist which lowers luteinizing hormone levels, also demonstrated spatial memory, comparable to that shown by T-, E-, or DHT-treated males. These data indicate that testicular androgens are important for maximal levels of spatial working memory in male rats, that testosterone may be converted to E and/or DHT to exert its effects, and that some of the effects of these steroid hormones may occur via negative feedback effects on LH.
