Multi-institutional Validation of a Vaginal Hysterectomy Simulation Model for Resident Training.

STUDY OBJECTIVE: The purpose of the research was to both develop a vaginal hysterectomy model with surgically pertinent anatomic landmarks and assess its validity for simulation training. DESIGN: A low-cost, reproducible vaginal hysterectomy model with relevant anatomic landmarks for key surgical steps. SETTING: Nine academic and community-based obstetrics and gynecology residency programs. PARTICIPANTS: One hundred sixty-nine obstetrics and gynecology residents. INTERVENTIONS: A vaginal hysterectomy model with surgically pertinent anatomic landmarks was developed and tested for construct validity. MEASUREMENTS AND MAIN RESULTS: Of the 184 available residents, 169 (91%) participated in this study and performed a vaginal hysterectomy procedure on the described model. The validated objective 7-item global rating scale (GRS) and the 13-item task-specific checklist (TSC) were used as tools to assess performance. The median TSC and GRS scores correlated with year of training, prior experience, and trainee confidence. In addition, the TSC scores also correlated with the GRS scores (p <.001) with regard to performance and resident year of training. Receiver Operator Curves for identification of the residents meeting national residency accreditation minimum numbers for vaginal hysterectomy using the GRS and TSC scores had an area under the curve of 0.89 and 0.83, respectively. CONCLUSION: This reduced-cost vaginal hysterectomy model offers high construct validity and pertinence for simulation.

Severity and threshold of peanut reactivity during hospital-based open oral food challenges: An international multicenter survey.

BACKGROUND: Peanut allergy is classically managed by food avoidance. Immunotherapy programs are available at some academic centers for selected patients reacting to small amounts of peanut during food challenge. We aimed to determine and compare reaction thresholds and prevalence of anaphylaxis during peanut oral challenges at multiple specialist allergy centers. METHODS: A retrospective, international survey of anonymized case records from seven specialist pediatric allergy centers from the UK and Ireland, as well as the Australian HealthNuts study. Demographic information, allergy test results, reaction severity and threshold during open oral peanut challenges were collated and analyzed. RESULTS: Of the 1634 children aged 1-18 years old included, 525 (32%) failed their peanut challenge. Twenty-eight percent reacted to 25 mg, while 38% only reacted after consuming 1 g or more of whole peanut. Anaphylaxis (55 [11%]) was 3 times more common in teenagers than younger children and the likelihood increased at all ages as children consuming more peanut at the challenge. Children who developed anaphylaxis to 25-200 mg of whole peanut were significantly older. Previous history of reaction did not predict reaction threshold or severity. CONCLUSIONS: More than a third of the children in this large international cohort tolerated the equivalent of one peanut in an oral challenge. Anaphylaxis, particularly to small amounts of peanut, was more common in older children. Tailored immunotherapy programs might be considered not only for children with low, but also higher reaction thresholds. Whether these programs could prevent heightened sensitivity and anaphylaxis to peanut with age also deserves further study.

Heme oxygenase-1 deficiency accompanies neuropathogenesis of HIV-associated neurocognitive disorders.

Heme oxygenase-1 (HO-1) is an inducible, detoxifying enzyme that is critical for limiting oxidative stress, inflammation, and cellular injury within the CNS and other tissues. Here, we demonstrate a deficiency of HO-1 expression in the brains of HIV-infected individuals. This HO-1 deficiency correlated with cognitive dysfunction, HIV replication in the CNS, and neuroimmune activation. In vitro analysis of HO-1 expression in HIV-infected macrophages, a primary CNS HIV reservoir along with microglia, demonstrated a decrease in HO-1 as HIV replication increased. HO-1 deficiency correlated with increased culture supernatant glutamate and neurotoxicity, suggesting a link among HIV infection, macrophage HO-1 deficiency, and neurodegeneration. HO-1 siRNA knockdown and HO enzymatic inhibition in HIV-infected macrophages increased supernatant glutamate and neurotoxicity. In contrast, increasing HO-1 expression through siRNA derepression or with nonselective pharmacologic inducers, including the CNS-penetrating drug dimethyl fumarate (DMF), decreased supernatant glutamate and neurotoxicity. Furthermore, IFN-γ, which is increased in CNS HIV infection, reduced HO-1 expression in cultured human astrocytes and macrophages. These findings indicate that HO-1 is a protective host factor against HIV-mediated neurodegeneration and suggest that HO-1 deficiency contributes to this degeneration. Furthermore, these results suggest that HO-1 induction in the CNS of HIV-infected patients on antiretroviral therapy could potentially protect against neurodegeneration and associated cognitive dysfunction.

Antiretroviral drugs induce oxidative stress and neuronal damage in the central nervous system.

HIV-associated neurocognitive disorder (HAND), characterized by a wide spectrum of behavioral, cognitive, and motor dysfunctions, continues to affect approximately 50 % of HIV(+) patients despite the success of combination antiretroviral drug therapy (cART) in the periphery. Of note, potential toxicity of antiretroviral drugs in the central nervous system (CNS) remains remarkably underexplored and may contribute to the persistence of HAND in the cART era. Previous studies have shown antiretrovirals (ARVs) to be neurotoxic in the peripheral nervous system in vivo and in peripheral neurons in vitro. Alterations in lipid and protein metabolism, mitochondrial damage, and oxidative stress all play a role in peripheral ARV neurotoxicity. We hypothesized that ARVs also induce cellular stresses in the CNS, ultimately leading to neuronal damage and contributing to the changing clinical and pathological picture seen in HIV-positive patients in the cART era. In this report, we show that ARVs are neurotoxic in the CNS in both pigtail macaques and rats in vivo. Furthermore, in vitro, ARVs lead to accumulation of reactive oxygen species (ROS), and ultimately induction of neuronal damage and death. Whereas ARVs alone caused some activation of the endogenous antioxidant response in vitro, augmentation of this response by a fumaric acid ester, monomethyl fumarate (MMF), blocked ARV-induced ROS generation, and neuronal damage/death. These findings implicate oxidative stress as a contributor to the underlying mechanisms of ARV-induced neurotoxicity and will provide an access point for adjunctive therapies to complement ARV therapy and reduce neurotoxicity in this patient population.

Dimethyl fumarate, an immune modulator and inducer of the antioxidant response, suppresses HIV replication and macrophage-mediated neurotoxicity: a novel candidate for HIV neuroprotection.

Despite antiretroviral therapy (ART), HIV infection promotes cognitive dysfunction and neurodegeneration through persistent inflammation and neurotoxin release from infected and/or activated macrophages/microglia. Furthermore, inflammation and immune activation within both the CNS and periphery correlate with disease progression and morbidity in ART-treated individuals. Accordingly, drugs targeting these pathological processes in the CNS and systemic compartments are needed for effective, adjunctive therapy. Using our in vitro model of HIV-mediated neurotoxicity, in which HIV-infected monocyte-derived macrophages release excitatory neurotoxins, we show that HIV infection dysregulates the macrophage antioxidant response and reduces levels of heme oxygenase-1 (HO-1). Furthermore, restoration of HO-1 expression in HIV-infected monocyte-derived macrophages reduces neurotoxin release without altering HIV replication. Given these novel observations, we have identified dimethyl fumarate (DMF), used to treat psoriasis and showing promising results in clinical trials for multiple sclerosis, as a potential neuroprotectant and HIV disease-modifying agent. DMF, an immune modulator and inducer of the antioxidant response, suppresses HIV replication and neurotoxin release. Two distinct mechanisms are proposed: inhibition of NF-κB nuclear translocation and signaling, which could contribute to the suppression of HIV replication, and induction of HO-1, which is associated with decreased neurotoxin release. Finally, we found that DMF attenuates CCL2-induced monocyte chemotaxis, suggesting that DMF could decrease recruitment of activated monocytes to the CNS in response to inflammatory mediators. We propose that dysregulation of the antioxidant response during HIV infection drives macrophage-mediated neurotoxicity and that DMF could serve as an adjunctive neuroprotectant and HIV disease modifier in ART-treated individuals.

NMDA receptor modulation by the neuropeptide apelin: implications for excitotoxic injury.

Excitotoxic neuronal damage via over-activation of the NMDA receptor has been implicated in many neurodegenerative diseases. In vitro modeling of excitotoxic injury has shown that activation of G-protein coupled receptors (GPCRs) counteracts such injury through modulation of neuronal pro-survival pathways and/or NMDA receptor signaling. We have previously demonstrated that the GPCR APJ and its endogenous neuropeptide ligand apelin can protect neurons against excitotoxicity, but the mechanism(s) of this neuroprotection remain incompletely understood. We hypothesized that apelin can promote neuronal survival by activating pro-survival signaling as well as inhibiting NMDA receptor-mediated excitotoxic signaling cascades. Our results demonstrate that (i) apelin activates pro-survival signaling via inositol trisphosphate (IP(3) ), protein kinase C (PKC), mitogen-activated protein kinase kinase 1/2 (MEK1/2), and extracellular signal-regulated kinase-1/2 (ERK1/2) to protect against excitotoxicity, and (ii) apelin inhibits excitotoxic signaling by attenuating NMDA receptor and calpain activity, and by modulating NMDA receptor subunit NR2B phosphorylation at serine 1480. These studies delineate a novel apelinergic signaling pathway that concurrently promotes survival and limits NMDA receptor-mediated injury to protect neurons against excitotoxicity. Defining apelin-mediated neuroprotection advances our understanding of neuroprotective pathways and will potentially improve our ability to develop therapeutics for excitotoxicity-associated neurodegenerative disorders.

The role of cuticular pheromones in courtship conditioning of Drosophila males.

Courtship conditioning is an associative learning paradigm in Drosophila melanogaster, wherein male courtship behavior is modified by experience with unreceptive, previously mated females. While the training experience with mated females involves multiple sensory and behavioral interactions, we hypothesized that female cuticular hydrocarbons function as a specific chemosensory conditioned stimulus in this learning paradigm. The effects of training with mated females were determined in courtship tests with either wild-type virgin females as courtship targets, or with target flies of different genotypes that express distinct cuticular hydrocarbon (CH) profiles. Results of tests with female targets that lacked the normal CH profile, and with male targets that expressed typically female CH profiles, indicated that components of this CH profile are both necessary and sufficient cues to elicit the effects of conditioning. Results with additional targets indicated that the female-specific 7,11-dienes, which induce naive males to court, are not essential components of the conditioned stimulus. Rather, the learned response was significantly correlated with the levels of 9-pentacosene (9-P), a compound found in both males and females of many Drosophila strains and species. Adding 9-P to target flies showed that it stimulates courting males to attempt to copulate, and confirmed its role as a component of the conditioned stimulus by demonstrating dose-dependent increases in the expression of the learned response. Thus, 9-P can contribute significantly to the conditioned suppression of male courtship toward targets that express this pheromone.

Abnormal expression of p27kip1 protein in levator ani muscle of aging women with pelvic floor disorders - a relationship to the cellular differentiation and degeneration.

BACKGROUND: Pelvic floor disorders affect almost 50% of aging women. An important role in the pelvic floor support belongs to the levator ani muscle. The p27/kip1 (p27) protein, multifunctional cyclin-dependent kinase inhibitor, shows changing expression in differentiating skeletal muscle cells during development, and relatively high levels of p27 RNA were detected in the normal human skeletal muscles. METHODS: Biopsy samples of levator ani muscle were obtained from 22 symptomatic patients with stress urinary incontinence, pelvic organ prolapse, and overlaps (age range 38-74), and nine asymptomatic women (age 31-49). Cryostat sections were investigated for p27 protein expression and type I (slow twitch) and type II (fast twitch) fibers. RESULTS: All fibers exhibited strong plasma membrane (and nuclear) p27 protein expression. cytoplasmic p27 expression was virtually absent in asymptomatic women. In perimenopausal symptomatic patients (ages 38-55), muscle fibers showed hypertrophy and moderate cytoplasmic p27 staining accompanied by diminution of type II fibers. Older symptomatic patients (ages 57-74) showed cytoplasmic p27 overexpression accompanied by shrinking, cytoplasmic vacuolization and fragmentation of muscle cells. The plasma membrane and cytoplasmic p27 expression was not unique to the muscle cells. Under certain circumstances, it was also detected in other cell types (epithelium of ectocervix and luteal cells). CONCLUSIONS: This is the first report on the unusual (plasma membrane and cytoplasmic) expression of p27 protein in normal and abnormal human striated muscle cells in vivo. Our data indicate that pelvic floor disorders are in perimenopausal patients associated with an appearance of moderate cytoplasmic p27 expression, accompanying hypertrophy and transition of type II into type I fibers. The patients in advanced postmenopause show shrinking and fragmentation of muscle fibers associated with strong cytoplasmic p27 expression.