In vitro Models of the Blood-Brain Barrier: Tools in Translational Medicine.

Medical progress has historically depended on scientific discoveries. Until recently, science was driven by technological advancements that, once translated to the clinic, fostered new treatments and interventions. More recently, technology-driven medical progress has often outpaced laboratory research. For example, intravascular devices, pacemakers for the heart and brain, spinal cord stimulators, and surgical robots are used routinely to treat a variety of diseases. The rapid expansion of science into ever more advanced molecular and genetic mechanisms of disease has often distanced laboratory-based research from day-to-day clinical realities that remain based on evidence and outcomes. A recognized reason for this hiatus is the lack of laboratory tools that recapitulate the clinical reality faced by physicians and surgeons. To overcome this, the NIH and FDA have in the recent past joined forces to support the development of a "human-on-a-chip" that will allow research scientists to perform experiments on a realistic replica when testing the effectiveness of novel experimental therapies. The development of a "human-on-a-chip" rests on the capacity to grow in vitro various organs-on-a-chip, connected with appropriate vascular supplies and nerves, and our ability to measure and perform experiments on these virtually invisible organs. One of the tissue structures to be scaled down on a chip is the human blood-brain barrier. This review gives a historical perspective on in vitro models of the BBB and summarizes the most recent 3D models that attempt to fill the gap between research modeling and patient care. We also present a summary of how these in vitro models of the BBB can be applied to study human brain diseases and their treatments. We have chosen NeuroAIDS, COVID-19, multiple sclerosis, and Alzheimer's disease as examples of in vitro model application to neurological disorders. Major insight pertaining to these illnesses as a consequence of more profound understanding of the BBB can reveal new avenues for the development of diagnostics, more efficient therapies, and definitive clarity of disease etiology and pathological progression.

Design and performance testing of a novel emergency ventilator for in-hospital use.

BACKGROUND: The rapidly evolving COVID-19 pandemic has led to increased use of critical care resources, particularly mechanical ventilators. Amidst growing concerns that the health care system could face a shortage of ventilators in the future, there is a need for an affordable, simple, easy to use, emergency stockpile ventilator. METHODS: Our team of engineers and clinicians designed and tested an emergency ventilator that uses a single limb portable ventilator circuit. The circuit is controlled by a pneumatic signal with electronic microcontroller input, using air and oxygen sources found in standard patient rooms. Ventilator performance was assessed using an IngMar ASL 5000 breathing simulator, and it was compared with a commercially available mechanical ventilator. RESULTS: The emergency ventilator provides volume control mode, intermittent mandatory ventilation and continuous positive airway pressure. It can generate tidal volumes between 300 and 800 mL with <10% error, with pressure, volume, and waveforms substantially equivalent to existing commercial ventilators. CONCLUSIONS: We describe a cost effective, safe, and easy to use ventilator that can be rapidly manufactured to address ventilator shortages in a pandemic setting. It meets basic clinical needs and can be provided for emergency use in cases requiring mechanical ventilation because of complications due to respiratory failure from infectious diseases.