Pipette Olympics: An Engaging Exercise for Undergraduate Laboratory Training

Pipetting is an important technique used in almost every molecular neuroscience method including but not limited to, PCR, reverse transcription, immunohistochemistry, chromatin immunoprecipitation, and cell culture. The COVID-19 pandemic has robbed the undergraduate population of time to practice in person laboratory techniques. In response, we have devised a standardized, quick, and fun way to instruct students on the fundamentals of pipetting, serial dilutions, and basic statistical analysis. Here, we offer a standardized protocol for instructors to use to teach undergraduates valuable skills while providing friendly competition. We also offer an example of an undergraduate performing the steps of this protocol with example results and the results from three separate undergrads' first two attempts. This exercise provides laboratories with a method to reintroduce undergraduates to lab basics while standardizing the training thereby saving time lost to the pandemic.

MicroRNA-338 inhibition protects against focal cerebral ischemia and preserves mitochondrial function in vitro in astrocytes and neurons via COX4I1

Brain-enriched microRNA-338 (miR-338) is known to play a central role in brain mitochondrial function, however the role of miR-338 in stroke injury remains unknown. This study investigated the role of miR-338 in injury from transient focal cerebral ischemia in mice, and in cell survival and mitochondrial function after in vitro ischemia in astrocyte and neuronal cultures. Pre-treatment of mice with intracerebroventricular injection of miR-338 antagomir 24 h prior to 1 h of middle cerebral artery occlusion (MCAO) significantly reduced infarct size and improved neurological score at both 24 h and 7d after injury. Levels of the miR-338 target cytochrome-c oxidase subunit 4I1 (COX4I1), which plays an essential role in maintaining brain mitochondrial ATP production, were increased in miR-338 antagomir-treated mice. Mouse primary astrocyte cell cultures subjected to glucose deprivation exhibited increased cell survival when pre-treated with miR-338 inhibitor, and greater cell death with miR-338 mimic. Decreased miR-338 levels were associated with increased ATP production, augmented cytochrome c oxidative (CcO) activity and preservation of COX4I1. In vitro protection with miR-338 inhibitor was blocked by concurrent knockdown of COX4I1 with small interfering RNA. Parallel studies in mouse neuronal N2a cultures resulted in preserved ATP content and CcO activity with miR-338 inhibition, indicating a shared miR-338-dependent response to ischemic stress between brain cell types. These results suggest that miR-338 inhibition and/or COX4I1-targeted therapies may be novel clinical strategies to protect against stroke injury via preservation of mitochondrial function in multiple cell types.

Tranexamic acid for postpartum hemorrhage prevention in vaginal delivery: A meta-analysis

BACKGROUND

Tranexamic acid (TA) has been demonstrated to reduce blood loss and the incidences of postpartum hemorrhage (PPH) during caesarean sections. We compared the clinical efficacy of TA administration on vaginal deliveries with recently published papers.

METHODS

Electronic databases of PubMed, Cochrane Library, Embase and Chinese CNKI (Chinese database) and Wanfang were searched through November 2019.The randomized controlled trials were selected between TA and control groups. The relevant studies included four trials with a total of 4579 patients.

RESULTS

Patients treated with TA had a reduction in total blood loss (P = .009), lower postoperative blood loss (P < .00001), a reduced number of PPH (P = .02). However, the occurrence of nausea or/and vomiting is higher in the TA group (the incidence of nausea or vomiting [P < .00001], nausea [P < .00001] and vomiting [P < .00001]).

CONCLUSION

TA resulted in fewer occurrence rates of PPH, and no significant increase in occurrences of dizziness or photopsia, but higher incidence of vomiting and nausea.

Adult neurogenesis from reprogrammed astrocytes

The details of adult neurogenesis, including environmental triggers, region specificity, and species homology remain an area of intense investigation. Slowing or halting age-related cognitive dysfunction, or restoring neurons lost to disease or injury represent just a fraction of potential therapeutic applications. New neurons can derive from stem cells, pluripotent neural progenitor cells, or non-neuronal glial cells, such as astrocytes. Astrocytes must be epigenetically “reprogrammed” to become neurons, which can occur both naturally in vivo, and via artificial exogenous treatments. While neural progenitor cells are localized to a few neurogenic zones in the adult brain, astrocytes populate almost every brain structure. In this review, we will summarize recent research into neurogenesis that arises from conversion of post-mitotic astrocytes, detail the genetic and epigenetic pathways that regulate this process, and discuss the possible clinical relevance in supplementing stem-cell neurogenic therapies.

Postinjury Inhibition of miR-181a Promotes Restoration of Hippocampal CA1 Neurons after Transient Forebrain Ischemia in Rats

The cellular and molecular mechanisms regulating postinjury neurogenesis in the adult hippocampus remain undefined. We have previously demonstrated that preinjury treatment with anti-microRNA (miR)-181a preserved neurons and prevented astrocyte dysfunction in the hippocampal cornu ammonis-1 (CA1) following transient forebrain ischemia. In the present study, we assessed postinjury treatment with anti-miR-181a on recovery of CA1 neurons following transient forebrain ischemia in rats. Stereotactic CA1 injection of miR-181a antagomir at either 2 h or 7 d postinjury resulted in improved restoration of CA1 measured at 28 d postinjury. Treatment with antagomir was associated with overexpression of the mir-181a target cell adhesion-associated, oncogene-related protein and enhanced expression of the neuroprogenitor cell marker doublecortin (DCX) in the CA1. Assessment of GFAP+ cell fate by Cre/Lox-mediated deletion demonstrated that some GFAP+ cells in CA1 exhibited de novo DCX expression in response to injury. In vitro experiments using primary neuronal stem cells confirmed that miR-181a inhibition augmented the expression of DCX and directed cellular differentiation toward a neuronal fate. These results suggest that miR-181a inhibition plays a central role in the restoration of CA1 neurons via augmentation of early latent neurogenic gene activation in neural progenitor cells, including some reactive astrocytes. Therapeutic interventions targeting this restorative process may represent a novel postinjury approach to improve clinical outcomes in survivors of forebrain ischemia.

Pre-treatment with microRNA-181a Antagomir Prevents Loss of Parvalbumin Expression and Preserves Novel Object Recognition Following Mild Traumatic Brain Injury

Mild traumatic brain injury (mTBI) can result in permanent impairment in memory and learning and may be a precursor to other neurological sequelae. Clinical treatments to ameliorate the effects of mTBI are lacking. Inhibition of microRNA-181a (miR-181a) is protective in several models of cerebral injury, but its role in mTBI has not been investigated. In the present study, miR-181a-5p antagomir was injected intracerebroventricularly 24 h prior to closed-skull cortical impact in young adult male mice. Paw withdrawal, open field, zero maze, Y maze, object location and novel object recognition tests were performed to assess neurocognitive dysfunction. Brains were assessed immunohistologically for the neuronal marker NeuN, the perineuronal net marker wisteria floribunda lectin (WFA), cFos, and the interneuron marker parvalbumin. Protein quantification was performed with immunoblots for synaptophysin and postsynaptic density 95 (PSD95). Fluorescent in situ hybridization was utilized to localize hippocampal miR-181a expression. MiR-181a antagomir treatment reduced neuronal miR-181a expression after mTBI, restored deficits in novel object recognition and increased hippocampal parvalbumin expression in the dentate gyrus. These changes were associated with decreased dentate gyrus hyperactivity indicated by a relative reduction in PSD95 and cFos expression. These results suggest that miR-181a inhibition may be a therapeutic approach to reduce hippocampal excitotoxicity and prevent cognitive dysfunction following mTBI.

Age-dependent sexual dimorphism in hippocampal cornu ammonis-1 perineuronal net expression in rats

INTRODUCTION

Perineuronal nets (PNNs) are extracellular matrices that encompass parvalbumin-expressing parvalbumin positive (PVALB+) fast-spiking inhibitory interneurons where they protect and stabilize afferent synapses. Recent observations that gonadal hormones influence PVALB+ neuron development suggest that PNN regulation may be sexually dimorphic. Sex differences in PNN abundance and complexity have been reported in sexually dimorphic nuclei in zebra finch brains; however, corresponding differences in mammalian brains have not been investigated.

METHODS

In this study we assessed the number of cortical and hippocampal PNNs in juvenile and young adult male and female rats using fluorescent immunohistochemistry for PVALB and the PNN marker Wisteria Floribunda Lectin.

RESULTS

We report here that PNNs are numerous and well developed in hippocampal cornu ammonis-1 of adult males but are lower in juvenile and possibly adult females. No significant differences were observed between sexes in cornu ammonis-3 or adjacent neocortex. There was an observed developmental difference in the neocortex as juveniles had more PVALB+ cells, but fewer PNN+ cells, than adults.

CONCLUSIONS

Because PNNs are integral for several hippocampal-mediated learning and memory tasks, these observations have potential sex-dependent translational implications for clinical strategies targeting cognitive dysfunction.

Abstract WMP76: Sexually Dimorphic Response to Stroke of miR-181a and miR-200c in Aged Mice

Background: Stroke is a sexually dimorphic disease with age-dependent sex differences in incidence, prevalence, and outcome. Delineating the molecular mechanisms that determine sexual dimorphism in stroke is necessary to overcome translational barriers and advance the development of novel stroke treatments. Non-coding RNAs, including microRNAs ( miRs ), are upstream regulators of genes that regulate cell survival. In young adult male animals, miR-181a and miR-200c have been established as central regulators in the cellular response to stroke, however their role in females or aged animal cohorts represents a critical knowledge gap. Therefore, in the present study we investigated the response of miR-181a and miR-200c in the brain after stroke in aged male and female mice.

Methods: Aged (20 month old) male and female mice were subjected to 1h middle cerebral artery occlusion (MCAO) followed by 24h reperfusion. RT-qPCR, fluorescent in situ hybridization (FISH) and immunohistochemistry (IHC) were used to quantify and localize post-MCAO cellular expression of miR-181a and miR-200c.

Results: There was no baseline difference in miR-181a between sexes, however miR-200c expression was ~3-fold higher at baseline in female animals versus males. MCAO induced ~2-fold increase in miR-181a in male animals but post-MCAO expression remained unchanged in females. In contrast, miR-200c expression increased by ~16-fold in males and ~4-fold in females. At baseline, miR-181a and miR-200c primarily localized to cortical neurons (NeuN+). In response to MCAO astrocyte reactivity (GFAP+) coincided with robust expression of miR-200c in both males and females.

Conclusions: MiR-181a and miR-200c exhibit sexual dimorphism in response to stroke. Augmented expression of miR-200c appears secondary to astrocyte reactivity. Future experiments will determine if inhibition of miR-181a and miR-200c are protective against ischemic stroke in aged animals.

Neurosurgical anesthesia for a pregnant woman with macroprolactinoma: A case report

RATIONALE

Being required to perform neurosurgery on a pregnant woman is rare, but occasionally unavoidable. In these cases, clinical anesthesiologists are confronted with conflicting information and few evidence-based guidelines.

PATIENT CONCERNS

Here, we describe the successful anesthetic management of a 24-week pregnant woman with macroprolactinoma who underwent endonasal transsphenoidal resection of pituitary adenoma.

DIAGNOSES

According to the prolactin (PRL) level and magnetic resonance imaging (MRI) results, the patient was diagnosed with macroprolactinoma and kept stable after taking the regular bromocriptine treatment. However, after stopping the drug by herself because of pregnancy, her tumor increased in size and she suffered from vision loss. Surgery was recommended as soon as possible to lessen the compression in the eye. However, the anesthetic management was a considerable risk due to the increased chance of maternal mortality, intrauterine growth restriction, or preterm labor.

INTERVENTIONS

We held a multidisciplinary meeting before the operation and made a detailed plan for how to proceed. During the operation, our team ensured intensive monitoring, provided adequate oxygen, and achieved haemodynamic stability. Anesthetics like sufentanyl, rocuronium, propofol, and desflurane were carefully chosen in order to ensure the safety of both the mother and fetus.

OUTCOMES

Under the careful and successful anesthetic management, the pregnant woman underwent the surgery smoothly and neither the mother nor baby experienced any pre- or postoperative complications. At the 38th week of gestation, the patient received a cesarean section and the baby had developed normally.

LESSONS

Neurosurgeries in pregnancy are sparse, and careful planning with cross-disciplinary specialists was needed in advance of the operation. Moreover, when dealing with such surgeries, we should consider the safety of both the mother and fetus, which is challenging but important.

Addendum to stress and the dynamic genome: Steroids, epigenetics, and the transposome

Retrotransposons constitute a majority of mammalian DNA, but their role in the cell is still poorly understood. Long thought to be useless, new evidence links retrotransposon expression to a variety of negative consequences. Furthermore, through interactions with steroid hormone receptors, retrotransposons are proposed to play a role in the pathology of psychological stress.

A zebrafish model of glucocorticoid resistance shows serotonergic modulation of the stress response

One function of glucocorticoids is to restore homeostasis after an acute stress response by providing negative feedback to stress circuits in the brain. Loss of this negative feedback leads to elevated physiological stress and may contribute to depression, anxiety, and post-traumatic stress disorder. We investigated the early, developmental effects of glucocorticoid signaling deficits on stress physiology and related behaviors using a mutant zebrafish, gr(s357), with non-functional glucocorticoid receptors (GRs). These mutants are morphologically inconspicuous and adult-viable. A previous study of adult gr(s357) mutants showed loss of glucocorticoid-mediated negative feedback and elevated physiological and behavioral stress markers. Already at 5 days post-fertilization, mutant larvae had elevated whole body cortisol, increased expression of pro-opiomelanocortin (POMC), the precursor of adrenocorticotropic hormone (ACTH), and failed to show normal suppression of stress markers after dexamethasone treatment. Mutant larvae had larger auditory-evoked startle responses compared to wildtype sibling controls (gr(wt)), despite having lower spontaneous activity levels. Fluoxetine (Prozac) treatment in mutants decreased startle responding and increased spontaneous activity, making them behaviorally similar to wildtype. This result mirrors known effects of selective serotonin reuptake inhibitors (SSRIs) in modifying glucocorticoid signaling and alleviating stress disorders in human patients. Our results suggest that larval gr(s357) zebrafish can be used to study behavioral, physiological, and molecular aspects of stress disorders. Most importantly, interactions between glucocorticoid and serotonin signaling appear to be highly conserved among vertebrates, suggesting deep homologies at the neural circuit level and opening up new avenues for research into psychiatric conditions.

The role of the T lymphocytic cell cycle and an autogenous lymphocytic factor in clinical medicine

In this study 315 individuals (25 controls, 290 chemically sensitive immunocompromised patients) were investigated. Each patient had been on a standard therapy of avoidance of pollutants, nutritional supplementation, and injections of antigens for foods, and biological inhalants, but did not attain their immunological competence. Peripheral lymphocytes were collected and DNA histograms were constructed. The flow cytometer was used to evaluate the cell cycle, haematological, and other immunological profiles. From the other portion of the blood specimen, lymphocytes were propagated in vitro, harvested, and a lysate, termed the autogenous lymphocytic factor (ALF), was prepared. When treated with ALF, 88% of these individuals showed a significant (p < 0.001) clinical improvement which correlated with laboratory findings, involving regulation of abnormal cell cycles, increase in total lymphocytes and subsets T4, T8, (p < 0.05) and cell mediated immunity (CMI) response (p < 0.001). The ALF presumably acts as a biological response modifier. The cell cycle and ALF provide clinical tools for diagnosis and regulation of immunological incompetence.

Kinetics of hemolysin production in bovine group B streptococci

Thirteen strains of group B streptococci etiologically related to bovine infections were investigated in order to observe the effects of non-hemoglobin iron and glucose on growth and hemolysin production; and to determine the necessity to stabilize the hemolysin with a carrier-stabilizer agent. Ferric citrate was diluted to give final concentrations of 1-11 micrograms/ml, added to iron-reduced (by CaCl2 precipitation) brain heart infusion media, inoculated and incubated at 37 degrees C. Parallel experiments were carried out with glucose. A variety of agents was employed to act as hemolysin stabilizers. Hemolysin production was detected by lysis of sheep erythrocytes. Both iron and glucose were crucial in concentrations 5-7 micrograms/ml and 0.5-1% respectively. Bovine serum albumin-starch mixture acted as an excellent stabilizer.

The role of iron in the growth and hemolysin (Streptolysin S) production in Streptococcus pyogenes

Four strains of Streptococcus pyogenes were propagated at 37 degrees C in a reduced iron medium supplemented with Fe3+-citrate to give concentrations of 1 through 11 micrograms per milliliter, in order to observe the effects of iron on growth and on the vitro production of Streptolysin S. Both growth and hemolysin production were observed to be influenced by medium iron concentration of which 1.2 micrograms per ml of iron was critical. Hemolysin was produced during the exponential phase of the growth cycle with maximum yield as the organism entered the stationary phase. Hemolytic activity (which was accepted as the ability of the hemolysin to lyse sheep erythrocytes) fell below detectable levels as the organisms entered fully into the stationary phase (9-10 hours post incubation). Serum (bovine, human, chicken) was observed to have a high stabilizing effect on the hemolysin.

Immunological response of chickens to eastern equine encephalomyelitis virus

The dominant immunoglobulin against eastern equine encephalomyelitis (EEE) virus and its duration and the longevity of the EEE virus haemagglutination inhibition (HI) antibodies were determined in sentinel and 125 immunised and hyperimmunised domestic chickens by enzyme-linked immunosorbent assay and the HI test respectively. The chickens ranged in age from 10 weeks to 18 months, were of varied pedigrees and from different countries. Results show that the HI antibody (IgG) is short-lived. It peaks and disappears within 30 days. The secondary response is dominated by the IgM immunoglobulin which is relatively long-lasting. These results are contrary to classical expectations and were observed in all the chickens studied. If these observations are found to be characteristic of birds generally, the present standard method of EEE virus seroepidemiological surveillance must be modified to be effective.

Epidemiological investigation for arboviruses in Jamaica, West Indies

Arbovirus investigation in Jamaica was undertaken between 1960 and 1975. Serological studies showed that antibodies to dengue type virus and St. Louis encephalitis virus (SLE) were prevalent throughout the island for several years. In urban communities, the incidence of dengue antibody was higher than for SLE; however, in children under 10 years of age antibody to both viruses was rarely present. In rural areas, SLE was prevalent in adults and children. This virus was isolated fom Culex nigripalpus (mosquitoes) and from a nestling Mockingbird, Mimus polyglottos, in the same rural area. Dengue type 3 and type 4 were isolated from the sera of patients in an urban area, during two epidemic periods, 1963 and 1968. No other group B arbovirus was encountered on the island. Group A arbovirus was virtually absent prior to the eastern equine encephalomyelitis outbreak of 1962. That virus was isolated from brain tissue of humans and equines. Two strains of Cache Valley virus from mosquitoes, Anopheles grabhami, one strain from Aedes taeniorhynchus, and a strain of Wad Medani virus from a tick, Amblyomma cajenense, were also isolated.

The role of chickens in the epidemiology of eastern equine encephalomyelitis virus in Jamaica

Since 1962, when Jamaica experienced its first and only outbreak of eastern equine encephalomyelitis (EEE), surveillance for the causative virus has been in progress. Wild birds, rodents, mosquitoes, sandflies and sentinels (domestic chickens, guinea pigs, mice and hamsters) have been constantly examined for EEE virus and serological conversion. In essence, only negative results have been obtained. Since June 1976, domestic chickens have been investigated as a possible reservoir and several have been found to have haemagglutinating antibodies, with titres ranging from 1:10 to 1:160. These titres fell rapidly, eg, from 1:160 to 1:10 within 60 days. These results incriminate the domestic fowl as a major reservoir for the virus, and suggest that the life of immunoglobulins against EEE is short in birds. Thus, the large number of negative serological tests found in previous investigations might be misleading since positive sera might have been missed between intervals of capture and recapture of the birds. The results indicate that investigators could usefully modify their procedure by bleeding wild birds as early as one to two weeks after initial capture. The importance and duration of the dominant avian anti-EEE virus immunoglobulins should be investigated.