Development of a high-throughput arrayed neural circuitry platform using human induced neurons for drug screening applications.

Proper brain function relies on the precise arrangement and flow of information between diverse neural subtypes. Developing improved human cell-based models which faithfully mimic biologically relevant connectivity patterns may improve drug screening efforts given the limited success of animal models to predict safety and efficacy of therapeutics in human clinical trials. To address this need, we have developed experimental models of defined neural circuitries through the compartmentalization of neuronal cell subtypes in a 96 well plate-based platform where each microwell is divided into two compartments connected by microchannels allowing high-throughput screening (HTS) of small molecules. We demonstrate that we can generate subtype-specific excitatory and inhibitory induced neuronal cells (iNs) from human stem cell lines and that these neurons form robust functional circuits with defined connectivity. Through the use of the genetically encoded calcium indicator GCaMP6f, we monitor calcium ion transients generated during neuronal firing between and within compartments. We further demonstrate functionality of the circuit by perturbing network activity through the addition of glutamate receptor blockers using automated liquid handling. Lastly, we show that we can stimulate network activity in defined neuronal subtypes through the expression of the designer receptor exclusively activated by designer drugs (DREADD) hM3Dq and application of the ligand clozapine-N-oxide (CNO). Our results demonstrate the formation of functional neural circuits in a high-throughput platform that is compatible with compound screening, representing an important step towards developing new screening platforms for studying and ultimately treating psychiatric brain disorders that arise from disordered neural circuit function.

Compartmentalized Devices as Tools for Investigation of Human Brain Network Dynamics.

Neuropsychiatric disorders have traditionally been difficult to study due to the complexity of the human brain and limited availability of human tissue. Induced pluripotent stem (iPS) cells provide a promising avenue to further our understanding of human disease mechanisms, but traditional 2D cell cultures can only provide a limited view of the neural circuits. To better model complex brain neurocircuitry, compartmentalized culturing systems and 3D organoids have been developed. Early compartmentalized devices demonstrated how neuronal cell bodies can be isolated both physically and chemically from neurites. Soft lithographic approaches have advanced this approach and offer the tools to construct novel model platforms, enabling circuit-level studies of disease, which can accelerate mechanistic studies and drug candidate screening. In this review, we describe some of the common technologies used to develop such systems and discuss how these lithographic techniques have been used to advance our understanding of neuropsychiatric disease. Finally, we address other in vitro model platforms such as 3D culture systems and organoids and compare these models with compartmentalized models. We ask important questions regarding how we can further harness iPS cells in these engineered culture systems for the development of improved in vitro models. Developmental Dynamics 248:65-77, 2019. © 2018 Wiley Periodicals, Inc.

µNeurocircuitry: Establishing in vitro models of neurocircuits with human neurons.

Neurocircuits in the human brain govern complex behavior and involve connections from many different neuronal subtypes from different brain regions. Recent advances in stem cell biology have enabled the derivation of patient-specific human neuronal cells of various subtypes for the study of neuronal function and disease pathology. Nevertheless, one persistent challenge using these human-derived neurons is the ability to reconstruct models of human brain circuitry. To overcome this obstacle, we have developed a compartmentalized microfluidic device, which allows for spatial separation of cell bodies of different human-derived neuronal subtypes (excitatory, inhibitory and dopaminergic) but is permissive to the spreading of projecting processes. Induced neurons (iNs) cultured in the device expressed pan-neuronal markers and subtype specific markers. Morphologically, we demonstrate defined synaptic contacts between selected neuronal subtypes by synapsin staining. Functionally, we show that excitatory neuronal stimulation evoked excitatory postsynaptic current responses in the neurons cultured in a separate chamber.

Self-mutilation of the lower lip in a child with dystonia secondary to megalencephalic leukoencephalopathy treated with botox injections: a case report.

PURPOSE: We report the case of a 10-year old boy who had been diagnosed with megalencephalic leukoencephalopathy several years earlier. Because of the patient's oral dystonic activity, a traumatic, nonhealing, chronic ulcer had developed on his lower lip. MATERIALS AND METHODS: Botox-A was injected into the mentalis, orbicularis oris, and bilateral masseter muscles. RESULTS: The patient showed decreased dystonia and gradual complete healing of the traumatic ulcer of the lower lip. CONCLUSIONS: The treatment of patients with self-mutilation to the lips will often be difficult. Traditionally, patients have been treated with various medications, oral appliances, and even tooth extraction. The results of the present case report suggest that Botox should be considered as a possible first-line strategy, along with oral appliances.

Oral rehabilitation of an edentulous patient using two-segment le fort I repositioning and implant-supported fixed prostheses.

Anteroposterior (AP) deficiencies present a restorative treatment challenge. Complex, multidisciplinary planning is necessary for the success of the treatment. This clinical report describes an approach to managing a complex complete oral rehabilitation of an edentulous patient with skeletal transverse and AP deficiencies with a history of facial trauma to the left zygomaticomaxillary complex. This was further complicated by a hopeless remaining dentition and pneumatization of the maxillary sinuses. Treatment included initial bony augmentation of the vertically and horizontally deficient maxilla, dental implant placement, provisional restoration in a Class III malocclusion with bilateral posterior crossbite, and Le Fort I osteotomy with transverse widening and advancement to correct the skeletal deficiency. Definitive restoration was accomplished with implant-supported fixed prostheses that provided ideal facial balance and occlusion.

Oral rehabilitation of a 12-year-old patient diagnosed with a central giant cell granuloma using a fibula graft and an implant-supported prosthesis: a clinical report.

This clinical report describes the oral rehabilitation of a 12-year-old boy with a central giant cell granuloma of the mandible. He underwent en bloc resection of a central giant cell granuloma, free vascularized fibula reconstruction, implant placement, and prosthesis fabrication. The multidisciplinary approach successfully restored function and esthetics. Considerations regarding the extensive surgical and prosthetic rehabilitation of a young adult with remaining growth are discussed.

Simultaneous intranasal procedures to improve chronic obstructive nasal breathing in patients undergoing maxillary (le fort I) osteotomy.

PURPOSE: The aim of this study was to evaluate the safety and efficacy of septoplasty and inferior turbinate reduction, carried out through a Le Fort I osteotomy as part of the correction of a dentofacial deformity, designed to improve nasal breathing in patients who reported pre-existing nasal airway obstruction and had documented septal deviation and inferior turbinate hypertrophy. PATIENTS AND METHODS: A validated outcomes instrument, the Nasal Obstruction Symptom Evaluation (NOSE) questionnaire, was used to objectively assess the extent of clinical nasal obstruction both before and after septoplasty and inferior turbinate reduction performed at the time of Le Fort I down-fracture. The study group comprised 43 consecutive patients scheduled for orthognathic surgery (including Le Fort I osteotomy) over a 12-month period who complained of chronic nasal obstruction and were found (by an independent otolaryngology evaluation) to have septal deviation and inferior turbinate hypertrophy unresponsive to medical therapy, who met the inclusion criteria, and who agreed to the procedures (septoplasty and turbinate reduction). The data collected included age, gender, health and social history, type of dentofacial deformity, concomitant surgical procedures, and any associated postoperative complications. RESULTS: For the 43 study patients, significant improvement in nasal breathing was documented (by NOSE scores) at 3 months (P < .001) after the procedures (Le Fort I osteotomy, septoplasty, and inferior turbinate reduction). Comparison of the 3-month and 6-month NOSE scores showed maintenance of improved nasal breathing with further improvement that did not demonstrate statistical significance. CONCLUSIONS: The findings of this study indicate that simultaneous management of the maxillary jaw deformity (Le Fort I osteotomy) and intranasal pathology (septoplasty and reduction of inferior turbinates) were effective for the symptomatic relief of nasal airway obstruction. The complication rate for the intranasal procedures completed simultaneously with a Le Fort I osteotomy was minimal and not dissimilar to the rates reported for each procedure performed as an isolated event.

The role of automated external defibrillators in dental practice.

Dental practices are seeing an increasing number of elderly and medically compromised patients, making it likely that staff will be called upon to respond to medical emergencies in the office, including cardiac arrest. Out-of-hospital cardiac arrests account for nearly half of all cardiovascular deaths in the United States. In adult cardiac arrest victims, the most frequent cause of sudden cardiac arrest is ventricular dysrhythmia, either ventricular tachycardia or ventricular fibrillation. The survival rate for sufferers of out-of-hospital cardiac arrests is a dismal 1% to 5% to hospital discharge. A majority of people who survive to discharge sustain significant morbidity. Untreated ventricular fibrillation degenerates into asystole, which is often refractory to resuscitative efforts and represents a terminal event. The development and availability of the automated external defibrillator (AED) represents a promising advance in the pre-hospital early defibrillation of victims of sudden cardiac arrest in a variety of settings, often remote from hospitals or EMS personnel. Given the medically compromised segment of the population treated in many dental practices today, it is imperative that dental practitioners and allied health providers become trained in the recognition and prompt initiation of emergency care, including basic life support with early defibrillation. The AED is becoming more accessible, with increasingly widespread availability, training in its use and relative ease of operation, making the goal of increased survival one in which dental health professionals can play a part.

Peripheral primitive neuroectodermal tumor associated with the anterior mandible: a case report and review of the literature.

Neuroectodermal tumors may arise in many places throughout the body including the diverse tissues of the head and neck. The primitive neuroectodermal tumor is a predominately neural, nonepithelial neoplasm similar to Ewing sarcoma. This article describes an 18-year-old female patient with a highly malignant peripheral primitive neuroectodermal tumor located in the soft tissue anterior to the mandibular symphysis. The clinical and radiographic presentation as well as the histopathology and immunohistochemistry of this rare entity is discussed. A review of the literature with respect to this tumor, as well as the current management of this tumor, is presented.