Live Animal Models Research Articles

Development of zebrafish medulloblastoma-like PNET model by TALEN-mediated somatic gene inactivation.

Genetically engineered animal tumor models have traditionally been generated by the gain of single or multiple oncogenes or the loss of tumor suppressor genes; however, the development of live animal models has been difficult given that cancer phenotypes are generally induced by somatic mutation rather than by germline genetic inactivation. In this study, we developed somatically mutated tumor models using TALEN-mediated somatic gene inactivation of cdkn2a/b or rb1 tumor suppressor genes in zebrafish. One-cell stage injection of cdkn2a/b-TALEN mRNA resulted in malignant peripheral nerve sheath tumors with high frequency (about 39%) and early onset (about 35 weeks of age) in F0 tp53e7/e7 mutant zebrafish. Injection of rb1-TALEN mRNA also led to the formation of brain tumors at high frequency (58%, 31 weeks of age) in F0 tp53e7/e7 mutant zebrafish. Analysis of each tumor induced by somatic inactivation showed that the targeted genes had bi-allelic mutations. Tumors induced by rb1 somatic inactivation were characterized as medulloblastoma-like primitive neuroectodermal tumors based on incidence location, histopathological features, and immunohistochemical tests. In addition, 3′ mRNA Quanti-Seq analysis showed differential activation of genes involved in cell cycle, DNA replication, and protein synthesis; especially, genes involved in neuronal development were up-regulated.

Surgical Training Improves Performance in Minimally Invasive Left Ventricular Assist Device Implantation Without Cardiopulmonary Bypass

We introduced a live animal model for training of minimally invasive implantation of a continuous-flow left ventricular assist device (CF-LVAD) without cardiopulmonary bypass for operator's performance improvement. After watching a videotape of LVAD implantation on the beating heart through the cardiac apex, the surgical team performed implantation of LVADs into 5 pigs during 3 training sessions in a time series. The procedure success rate, operating time, and technical and global performances by self-evaluation and senior evaluation were compared among the sessions. Animal Experiment Center in Peking University Third Hospital. Surgical team comprising a surgical operator, surgical assistant, anesthetist, and scrub nurse performed 3 training sessions in a time series. The urgent situations requiring proper management were myocardial laceration, massive blood loss, and ventricular arrhythmia induced by hemodynamic instability. After practice, the success rate increased to 100% in session 3. The operating times of session 2 (189.80 ± 14.34min) and session 3 (149.00 ± 22.85min) were significantly lower than that of session 1 (262.20 ± 28.26min). The technical and global performances by self-evaluation and senior evaluation were significantly better in session 3 than session 1. Simulation training with high-fidelity in vivo model for minimally invasive CF-LVAD implantation improves the surgical team's global performance, success rate, and the ability to manage emergency situations in surgery.

English

Newcastle disease virus is a paramyxovirus which causes Newcastle disease in birds. Investigation was done on the effect of leaf extract of Phyllanthus amarus against Newcastle disease virus (NDV) using an in-ovo assay. Nine to eleven day-old viable embryonated chicken eggs (ECE) were used for the assay, these were divided into six groups of six eggs each. Methanol, aqueous and n-hexane extracts of the plant leaves were administered to the various groups at concentrations varying from 50 to 5 mg/ml. Embryonated eggs were incubated and embryo survival was monitored daily. Negative control and diluents control groups received phosphate buffer saline (PBS) and dimethly suphoxide (DMSO), respectively. The other group was uninoculated while a virus control group received 100 EID50/0.1 ml NDV alone. Bacteria free allantoic fluid from the embryonated eggs in different treatment groups were harvested and collected for spot hemagglutination (HA) test and HA assay to detect the presence of NDV viral particles and the viral titre, respectively. Leaf extracts were assayed for presence of phytochemicals and antioxidant potentials. It was observed from the results that the extract was toxic to the embryo at a concentration above 50 mg/ml and further results showed that the HA viral titre reduction was directly proportional to increasing extract concentration. The phytochemical assays of leaf extract revealed the presence of phytochemicals including alkaloids, tannins, saponins, flavonoids, phenols, steroids, glycosides. The current findings have demonstrated that leaf extract from P. amarus has potentials of medicinal value as well as antiviral activity against NDV in-ovo. Further experimental assays using live animal models are recommended to validate the use of P. amarus plant extract in therapeutic measure in chickens. Key words: Antiviral, Phyllanthus amarus, Newcastle disease virus (NDV), embryonated chicken eggs (ECE).

Why Does Bone Remodel, What Happens When It Doesn't, and How Can We Use This to Change Our Therapeutic Mindset?

Bone remodeling serves both long‐term metabolic as well as mechanical needs. Within the mechanical realm, remodeling helps to renew the bone matrix to prevent the tissue from aging to the point at which its mechanical properties are compromised, and skeletal fragility is increased. It is now well known that severely suppressing bone remodeling is as detrimental to skeletal health as is the rapid bone remodeling found in conditions such as osteoporosis or Paget's Disease. Failure to remodel bone can result in excessive microdamage burden, accumulation of advanced glycation end products (AGEs), and hypermineralization. Microdamage, left unrepaired, reduces the residual strength and stiffness of bone, and can lead to stress fractures. Hypermineralization and accumulation of AGEs cause tissue brittleness, which reduce bone toughness and increase the risk for fracture. Many current treatments for postmenopausal, glucocorticoid‐induced and age‐related osteoporosis prevent bone loss by suppressing bone remodeling, reducing the risk for some kinds of fractures (eg hip fractures), but this has negative effects on tissue material properties that may increase the risk for other types of fractures (stress fractures and atypical femoral fractures). Knowing this, investigations have begun into how to alter the physical properties of bone matrix without manipulating the activity of osteoclasts or osteoblasts. These cell independent approaches rely on moving bone water from compartments in which it is freely flowing, to those in which it is tightly bound, within the interface between the collagen and the mineral. Increasing bound water allows the collagen and mineral to slide at their interfaces, reducing stresses when bone is loaded, and delaying both the initiation of microcracks and the ultimate fracture of the bone. Agents that increase water content of bone, and move water between compartments, have been tested both ex vivo, and in living animal models. They have been shown to increase toughness in bone that is devoid of living cells. These agents have also been shown in diabetic animal models to reduce the skeletal fragility that is associated with Type II diabetes, a case in which fragility is not related to bone mass but only to the deterioration of matrix material properties consequent to AGE accumulation. These treatments offer the opportunity to reduce risk for fracture without manipulating cell activity. Given the importance of a vital and viable remodeling system to bone health, these new approaches promise an approach to reduce fracture risk without negative side effects associated with suppressing remodeling, and can be applied to cases of skeletal fragility that are not caused by aberrations of the remodeling system.

Heterologous Matrix Metalloproteinase Gene Promoter Activity Allows In Vivo Real-time Imaging of Bleomycin-Induced Lung Fibrosis in Transiently Transgenized Mice.

Idiopathic pulmonary fibrosis is a very common interstitial lung disease derived from chronic inflammatory insults, characterized by massive scar tissue deposition that causes the progressive loss of lung function and subsequent death for respiratory failure. Bleomycin is used as the standard agent to induce experimental pulmonary fibrosis in animal models for the study of its pathogenesis. However, to visualize the establishment of lung fibrosis after treatment, the animal sacrifice is necessary. Thus, the aim of this study was to avoid this limitation by using an innovative approach based on a double bleomycin treatment protocol, along with the in vivo images analysis of bleomycin-treated mice. A reporter gene construct, containing the luciferase open reading frame under the matrix metalloproteinase-1 promoter control region, was tested on double bleomycin-treated mice to investigate, in real time, the correlation between bleomycin treatment, inflammation, tissue remodeling and fibrosis. Bioluminescence emitted by the lungs of bleomycin-treated mice, corroborated by fluorescent molecular tomography, successfully allowed real time monitoring of fibrosis establishment. The reporter gene technology experienced in this work could represent an advanced functional approach for real time non-invasive assessment of disease evolution during therapy, in a reliable and translational living animal model.

Training in endoscopic ultrasonography: An Asian perspective.

Training of endoscopic ultrasonography (EUS) in Asia faces two major challenges: (i) the ever-increasing demand for skills to handle a growing range of interventional EUS procedures; and (ii) a continual shortage of EUS training programs. As the therapeutic application of EUS continues to expand, the need to train more new endosonographers and upgrade skills of existing ones has become more critical than ever before. A formal fellowship to acquire EUS knowledge and skills in an advanced endoscopy center has always been perceived as the best way of training novices, but such opportunities remain limited in most Asian countries. To keep up with the pace of development in EUS, more short-term EUS programs have been conducted across Asia in recent years. Such programs are generally intensive and may combine didactic lectures, live-case demonstrations, and hands-on training on phantoms, or live animal models for teaching. Although not as rigorous as conventional full-time EUS fellowships, such short-term programs are not necessarily inferior in quality. With courses offered from basic to advanced levels, and at regular intervals, busy practising endoscopists have the flexibility to attend the course that best matches their individual levels of experience, learn at their own pace and acquire EUS knowledge and skills over as many courses as desired. This open-ended progressive learning model is more agile than established fixed-term learning models and is expected to adapt better to future needs.

Engineering Carbon Nanotube Fiber for Real-Time Quantification of Ascorbic Acid Levels in a Live Rat Model of Alzheimer's Disease.

Ascorbic acid (AA) levels are closely correlated with physiological and pathological events in brain diseases, but the mechanism remains unclear, mainly due to the difficulty of accurately analyzing AA levels in live brain. In this study, by engineering tunable defects and oxygen-containing species in carbon nanotubes, a novel aligned carbon nanotube fiber was developed as an accurate microsensor for the ratiometric detection of AA levels in live rat brains with Alzheimer's disease (AD). AA oxidation is greatly facilitated on the fiber surface at a low potential, leading to high sensitivity as well as high selectivity against potential sources of interference in the brain. Additionally, an unexpected, separate peak from the fiber surface remains constant as the AA concentration increases, enabling real-time and ratiometric detection with high accuracy. The results demonstrated that the AA levels were estimated to be 259 ± 6 μM in cortex, 264 ± 20 μM in striatum, and 261 ± 21 μM in hippocampus, respectively, in normal condition. However, the overall AA level was decreased to 210 ± 30 μM in cortex, 182 ± 5 μM in striatum, and 136 ± 20 μM in hippocampus in the rat brain model of AD. To the best of our knowledge, this work is the first to accurately detect AA concentrations in the brains of live animal model of AD.

A Randomized Comparison of Bougie-Assisted and TracheoQuick Plus Cricothyrotomies on a Live Porcine Model.

Objectives Cricothyrotomy is a rescue procedure in “cannot intubate, cannot oxygenate” scenarios where other methods of nonsurgical airway management have failed. We compared 2 cuffed cricothyrotomy sets, bougie-assisted cricothyrotomy (BACT) and novel percutaneous TracheoQuick Plus, on a live porcine model in a simulated periarrest situation. Methods Thirty-four anesthetized minipigs were randomly allocated into two groups: BACT technique (n = 17) and TracheoQuick Plus (n = 17). The primary outcome was duration of cricothyrotomy while secondary outcomes were total success rate, number of attempts, location of incision, changes in heart rate, oxygen saturation, and the incidence of complications. Results BACT was significantly faster than TracheoQuick Plus cricothyrotomy, with a median time of 69 sec (IQR 56–85) versus 178 sec (IQR 152–272). The total success rate was without difference. 94% of BACT was performed successfully on the first attempt, while in the TracheoQuick Plus group, it was only 18% (P < 0.001). Trauma to the posterior tracheal wall was observed once in the BACT group and 5 times in the TracheoQuick Plus group. Oxygen saturation was significantly higher in the BACT group both during and after the procedure. Conclusions BACT is superior to TracheoQuick Plus cricothyrotomy on a live animal model.

Precision Optogenetic Tool for Selective Single- and Multiple-Cell Ablation in a Live Animal Model System

Cell ablation is a strategy to study cell lineage andfunction during development. Optogenetic methods are an important cell-ablation approach, and we have previously developed a mini singlet oxygen generator (miniSOG) tool that works in the living Caenorhabditis elegans. Here, we use directed evolution to generate miniSOG2, an improved tool forcell ablation via photogenerated reactive oxygen species. We apply miniSOG2 to a far more complex model animal system, Drosophila melanogaster, and demonstrate that it can be used to kill a single neuron in a Drosophila larva. In addition, miniSOG2 is able to photoablate a small group of cells in one of the larval wing imaginal discs, resulting in an adult with one incomplete and one normal wing. We expect miniSOG2 to be a useful optogenetic tool for precision cell ablation at a desired developmental time point in live animals, thus opening a new window into cell origin, fate and function, tissue regeneration, and developmental biology.

Development of an Autonomous Endoscopically Implantable Submucosal Microdevice Capable of Neurostimulation in the Gastrointestinal Tract.

Gastric dysmotility can be a sign of common diseases such as longstanding diabetes mellitus. It is known that the application of high-frequency low-energetic stimulation can help to effectively moderate and alleviate the symptoms of gastric dysmotility. The goal of our research was the development of a miniature, endoscopically implantable device to a submucosal pocket. The implantable device is a fully customized electronics package which was specifically designed for the purpose of experiments in the submucosa. The device was endoscopically inserted into the submucosal pocket of a pig stomach and partially severed pig side in order to adequately simulate a live animal model. The experiment confirmed that the designed device can be implanted into the submucosa and is capable of the measurement of sensor data and the transmission of this data wirelessly in real time to a computer outside of the body. After proving that the device can be implanted submucosally and transmit data, further experiments can now be performed, primarily with an electrogastrography (EGG) instrument and implantable device with tissue stimulation capability.

Visualization of Probiotic-Mediated Ca2+ Signaling in Intestinal Epithelial Cells In Vivo.

Probiotics, such as lactic acid bacteria (LAB) and Bacillus subtilis var. natto, have been shown to modulate immune responses. It is important to understand how probiotic bacteria impact intestinal epithelial cells (IECs), because IECs are the first line of defense at the mucosal surface barrier and their activities substantially affect the gut microenvironment and immunity. However, to date, their precise mechanism remains unknown due to a lack of analytical systems available for live animal models. Recently, we generated a conditional Ca2+ biosensor Yellow Cameleon (YC3.60) transgenic mouse line and established 5D (x, y, z, time, and Ca2+) intravital imaging systems of lymphoid tissues including those in Peyer’s patches and bone marrow. In the present study, we further advance our intravital imaging system for intestinal tracts to visualize IEC responses against orally administrated food compounds in real time. Using this system, heat-killed B. subtilis natto, a probiotic TTCC012 strain, is shown to directly induce Ca2+ signaling in IECs in mice housed under specific pathogen-free conditions. In contrast, this activation is not observed in the Lactococcus lactis strain C60; however, when we generate germ-free YC3.60 mice and observe the LAB stimulation of IECs in the absence of gut microbiota, C60 is capable of inducing Ca2+ signaling. This is the first study to successfully visualize the direct effect of probiotics on IECs in live animals. These data strongly suggest that probiotic strains stimulate IECs under physiological conditions and that their activity is affected by the microenvironment of the small intestine, such as commensal bacteria.

Development of bioluminescence imaging of respiratory syncytial virus (RSV) in virus-infected live mice and its use for evaluation of therapeutics and vaccines

Respiratory Syncytial virus (RSV) is one of the leading causes of pneumonia among infants with no human vaccine or efficient curative treatments. Efforts are underway to develop new RSV vaccines and therapeutics. There is a dire need for animal models for preclinical evaluation and selection of products against RSV. Herein, we developed a whole body bioluminescence imaging to follow replication of RSV A2 virus strain expressing firefly luciferase (RSVA2-line19-FFL) in live BALB/c mice that can be used as an extremely sensitive readout for studying effects of antiviral and vaccines in living mice. Strong bioluminescence signal was detected in the nasal cavity and in the lungs following intranasal infection of mice with RSVA2-line19-FFL. The kinetics of viral replication in lungs quantified by daily live imaging strongly correlated with viral titers measured by ex-vivo plaque assay and by assessing viral RNA by qRT-PCR. Vaccination of mice with a pre-fusion F protein elicited high neutralizing antibody titers conferring strong protective immunity against virus replication in the nasal cavity and lungs. In contrast, post-challenge treatment of mice with the monoclonal antibody Palivizumab two days after infection reduced viral replication in the nasal cavity at day 4, but only modestly reduced virus loads in the lungs by day 5. In contrast to RSV bioluminescence, plaque assay did not detect viral titers in lungs on day 5 in Palivizumab-treated animals. This difference between viral loads measured by the two assays was found to be due to coating of virions with the Palivizumab that blocked infection of target cells in vitro and shows importance of live imaging in evaluation of RSV therapeutics. This recombinant RSV based live imaging animal model is convenient and valuable tool that can be used to study host dissemination of RSV and evaluation of antiviral compounds and vaccines against RSV.

Automated Microsampling Technologies and Enhancements in the 3Rs.

Data collected in vivo is essential for advising decisions on drug screening and development and basic research, and animal models are used extensively for acquiring experimental measurements. Traditionally, collection of specimens has been invasive, stressful to animal subjects, labor intensive, time-consuming and costly, and required many animals when using small models with low fluid volumes, such as rats or mice. Utilizing automated microsampling (AMS) alone or in an integrative pharmacology approach to evaluate multiple physiological, pharmacokinetic, and pharmacodynamic endpoints simultaneously in the same animal accomplishes multiple experimental goals. Use of AMS robotics and associated instrumentation can assist in achieving significant reduction and refinement of animal use. Automated robotic instrumentation for specimen collection from living animal models can now be used to provide better quality pharmacokinetic and pharmacodynamic data, reduce time, provide more data with less variability, reduce animal use, and refine animal model use to reduce pain and stress. Instrumentation in common use for automated sampling and dosing is briefly discussed. In parallel with advances in automated instrumentation, recent advances in analytical detection methods complement the use of automated technology for data and specimen collection. Methods requiring much smaller volumes can now be utilized. Microsampling (small biological samples in volumes of 5-100 μL) can facilitate reduction in animal numbers while minimizing stresses associated with excessive fluid volume removal. Innovations in automation, microsampling techniques, and analytical methods have facilitated advances in data collection that allow for more robust and accurate data, reduction in animal use, and refinement in techniques that improve animal welfare. These innovations offer opportunities for wider application in nonclinical investigations by collection of multiple data streams simultaneously from individual animals. Many benefits are achievable through the use integrative pharmacology designs utilizing AMS, including decreased time for completion of composite data collection, decreased personnel resources, lower costs, improved safety, higher quality and multiple data-sets, and improvements in aspects of the 3Rs.

Flunarizine rescues reduced lifespan in CLN3 triple knock-out Caenorhabditis elegans model of batten disease.

CLN3 disease (Spielmeyer-Vogt-Sjogren-Batten disease, previously known as classic juvenile neuronal ceroid lipofuscinosis, NCL) is a pediatric-onset progressive neurodegenerative disease characterized by progressive vision loss, seizures, loss of cognitive and motor function, and early death. While no precise biochemical mechanism or therapies are known, the pathogenesis of CLN3 disease involves intracellular calcium accumulation that may trigger apoptosis. Our prior work in in vitro cell models of CLN3 deficiency suggested that FDA-approved calcium channel antagonists may have therapeutic value. To further evaluate the potential efficacy of this approach in an otherwise untreatable disorder, we sought to compare the therapeutic effects and underlying mechanisms in an animal model of CLN3 disease. Here, we used the well-characterized XT7 complete cln-3 knockout strain of C. elegans to evaluate the therapeutic efficacy of calcium channel antagonist therapy in a living animal model of Batten disease. Therapeutic effects of five calcium channel antagonists were evaluated on XT7 animal lifespan and in vivo mitochondrial physiology. Remarkably, maximal therapeutic efficacy in this model animal was observed with 1μM flunarizine, the identical concentration previously identified in cell-based neuronal models of CLN3 disease. Specifically, flunarizine rescued the short lifespan of XT7 worms and prevented their pathophysiologic mitochondrial accumulation. These results confirm the treatment efficacy and dosing of flunarizine in cln-3 disease in a translational model organism. Clinical treatment trials in CLN3 human patients are now needed to test the dosing regimen and efficacy of flunarizine in individuals suffering with this otherwise untreatable and ultimately lethal neurologic disease.

In-vivo, non-invasive detection of hyperglycemic states in animal models using mm-wave spectroscopy.

Chronic or sustained hyperglycemia associated to diabetes mellitus leads to many medical complications, thus, it is necessary to track the evolution of patients for providing the adequate management of the disease that is required for the restoration of the carbohydrate metabolism to a normal state. In this paper, a novel monitoring approach based on mm-wave spectroscopy is comprehensively described and experimentally validated using living animal models as target. The measurement method has proved the possibility of non-invasive, in-vivo, detection of hyperglycemia-associated conditions in different mouse models, making possible to clearly differentiate between several hyperglycemic states.

Ex-vivo and live animal models are equally effective training for the management of a penetrating cardiac injury.

BackgroundLive tissue models are considered the most useful simulation for training in the management for hemostasis of penetrating injuries. However, these models are expensive, with limited opportunities for repetitive training. Ex-vivo models using tissue and a fluid pump are less expensive, allow repetitive training and respect ethical principles in animal research. The purpose of this study is to objectively evaluate the effectiveness of ex-vivo training with a pump, compared to live animal model training. Staff surgeons and residents were divided into live tissue training and ex-vivo training groups. Training in the management of a penetrating cardiac injury was conducted for each group, separately. One week later, all participants were formally evaluated in the management of a penetrating cardiac injury in a live animal.ResultsThere are no differences between the two groups regarding average years of experience or previous trauma surgery experience. All participants achieved hemostasis, with no difference between the two groups in the Global Rating Scale score (ex-vivo: 25.2 ± 6.3, live: 24.7 ± 6.3, p = 0.646), blood loss (1.6 ± 0.7, 2.0 ± 0.6, p = 0.051), checklist score (3.7 ± 0.6, 3.6 ± 0.9, p = 0.189), or time required for repair (101 s ± 31, 107 s ± 15, p = 0.163), except overall evaluation (3.8 ± 0.9, 3.4 ± 0.9, p = 0.037). The internal consistency reliability and inter-rater reliability in the Global Rating Scale were excellent (0.966 and 0.953 / 0.719 and 0.784, respectively), and for the checklist were moderate (0.570 and 0.636 / 0.651 and 0.607, respectively). The validity is rated good for both the Global Rating Scale (Residents: 21.7 ± 5.6, Staff: 28.9 ± 4.7, p = 0.000) and checklist (Residents: 3.4 ± 0.9, Staff Surgeons: 3.9 ± 0.3, p = 0.003). The results of self-assessment questionnaires were similarly high (4.2–4.9) with scores in self-efficacy increased after training (pre: 1.7 ± 0.8, post: 3.2 ± 1.0, p = 0.000 in ex-vivo, pre: 1.9 ± 1.0, post: 3.7 ± 0.7, p = 0.000 in live). Scores comparing pre-training and post-evaluation (pre: 1.7 ± 0.8, post: 3.7 ± 0.9, p = 0.000 in ex-vivo, pre: 1.9 ± 1.0, post: 3.8 ± 0.7, p = 0.000 in live) were increased.ConclusionTraining with an ex-vivo model and live tissue training are similar for the management of a penetrating cardiac injury, with increased self-efficacy of participants in both groups. The ex-vivo model is useful to learn hemostatic skills in trauma surgery.Electronic supplementary materialThe online version of this article (doi:10.1186/s13017-016-0104-3) contains supplementary material, which is available to authorized users.

Opioids and tumour metastasis: does the choice of the anesthetic-analgesic technique influence outcome after cancer surgery?

Cancer is now one of the leading causes of death worldwide, and excisional surgery is an essential treatment for the four most common adult cancers. Opioids remain the most commonly prescribed analgesics in the perioperative period of cancer surgery, yet the question of whether opioids could influence recurrence or metastasis remains unanswered. In-vitro cell culture, live animal models, and retrospective clinical reviews investigating the effects of opioids on outcomes after cancer surgery have yielded conflicting results, with findings ranging from deleterious, null to potentially protective effects. Prospective randomized trials are required to investigate this important topic further. Several are currently ongoing. Until the results of these are available for scrutiny, there is currently insufficient evidence to recommend any changes to current clinical practice. Opioids continue to play an important role in the perioperative period.

A critical role for the self-assembly of Amyloid-β1-42 in neurodegeneration.

Amyloid β1-42 (Aβ1-42) plays a central role in Alzheimer’s disease. The link between structure, assembly and neuronal toxicity of this peptide is of major current interest but still poorly defined. Here, we explored this relationship by rationally designing a variant form of Aβ1-42 (vAβ1-42) differing in only two amino acids. Unlike Aβ1-42, we found that the variant does not self-assemble, nor is it toxic to neuronal cells. Moreover, while Aβ1-42 oligomers impact on synaptic function, vAβ1-42 does not. In a living animal model system we demonstrate that only Aβ1-42 leads to memory deficits. Our findings underline a key role for peptide sequence in the ability to assemble and form toxic structures. Furthermore, our non-toxic variant satisfies an unmet demand for a closely related control peptide for Aβ1-42 cellular studies of disease pathology, offering a new opportunity to decipher the mechanisms that accompany Aβ1-42-induced toxicity leading to neurodegeneration.

Status of Microsurgical Simulation Training in Plastic Surgery: A Survey of United States Program Directors.

Various simulation models for microsurgery have been developed to overcome the limitations of Halstedian training on real patients. We wanted to assess the status of microsurgery simulation in plastic surgery residency programs in the United States. Data were analyzed from responses to a survey sent to all plastic surgery program directors in the United States, asking for type of simulation, quality of facilities, utilization by trainees, evaluation of trainee sessions, and perception of the relevance of simulation. The survey response rate was 50%. Of all programs, 69% provide microsurgical simulation and 75% of these have a laboratory with microscope and 52% provide live animal models. Half share facilities with other departments. The quality of facilities is rated as good or great in 89%. Trainee utilization is once every 3 to 6 months in 82% of programs. Only in 11% is utilization monthly. Formal evaluation of simulation sessions is provided by 41% of programs. All program directors agree simulation is relevant to competence in microsurgery, 60% agree simulation should be mandatory, and 43% require trainees to complete a formal microsurgery course prior to live surgery. There seems to be consensus that microsurgical simulation improves competence, and the majority of program directors agree it should be mandatory. Developing and implementing standardized simulation modules and assessment tools for trainees across the nation as part of a comprehensive competency-based training program for microsurgery is an important patient safety initiative that should be considered. Organizing with other departments to share facilities may improve their quality and hence utilization.

Training and Assessment of Hysteroscopic Skills: A Systematic Review

The aim of this systematic review was to identify studies on hysteroscopic training and assessment. PubMed, Excerpta Medica, the Cochrane Library, and Web of Science were searched in January 2015. Manual screening of references and citation tracking were also performed. Studies on hysteroscopic educational interventions were selected without restrictions on study design, populations, language, or publication year. A qualitative data synthesis including the setting, study participants, training model, training characteristics, hysteroscopic skills, assessment parameters, and study outcomes was performed by 2 authors working independently. Effect sizes were calculated when possible. Overall, 2 raters independently evaluated sources of validity evidence supporting the outcomes of the hysteroscopy assessment tools. A total of 25 studies on hysteroscopy training were identified, of which 23 were performed in simulated settings. Overall, 10 studies used virtual-reality simulators and reported effect sizes for technical skills ranging from 0.31 to 2.65; 12 used inanimate models and reported effect sizes for technical skills ranging from 0.35 to 3.19. One study involved live animal models; 2 studies were performed in clinical settings. The validity evidence supporting the assessment tools used was low. Consensus between the 2 raters on the reported validity evidence was high (94%). This systematic review demonstrated large variations in the effect of different tools for hysteroscopy training. The validity evidence supporting the assessment of hysteroscopic skills was limited.