Intravenous xenogeneic transplantation of human adipose-derived stem cells improves left ventricular function and microvascular integrity in swine myocardial infarction model.

OBJECTIVES: The potential for beneficial effects of adipose-derived stem cells (ASCs) on myocardial perfusion and left ventricular dysfunction in myocardial ischemia (MI) has not been tested following intravenous delivery. METHODS: Surviving pigs following induction of MI were randomly assigned to 1 of 3 different groups: the placebo group (n = 7), the single bolus group (SB) (n = 7, 15 × 10(7) ASCs), or the divided dose group (DD) (n = 7, 5 × 10(7) ASCs/day for three consecutive days). Myocardial perfusion defect area and coronary flow reserve (CFR) were compared during the 28-day follow-up. Also, serial changes in the absolute number of circulating CD4(+) T and CD8(+) T cells were measured. RESULTS: The increases in ejection fraction were significantly greater in both the SB and the DD groups compared to the placebo group (5.4 ± 0.9%, 3.7 ± 0.7%, and -0.4 ± 0.6%, respectively), and the decrease in the perfusion defect area was significantly greater in the SB group than the placebo group (-36.3 ± 1.8 and -11.5 ± 2.8). CFR increased to a greater degree in the SB and the DD groups than in the placebo group (0.9 ± 0.2, 0.8 ± 0.1, and 0.2 ± 0.2, respectively). The circulating number of CD8(+) T cells was significantly greater in the SB and DD groups than the placebo group at day 7 (3,687 ± 317/µL, 3,454 ± 787/µL, and 1,928 ± 457/µL, respectively). The numbers of small vessels were significantly greater in the SB and the DD groups than the placebo group in the peri-infarct area. CONCLUSIONS: Both intravenous SB and DD delivery of ASCs are effective modalities for the treatment of MI in swine. Intravenous delivery of ASCs, with its immunomodulatory and angiogenic effects, is an attractive noninvasive approach for myocardial rescue.

Knee Extension Lag Treated with Posterior Capsulotomy of the Knee: A Case Report and Review of the Literature.

Introduction: The posterior capsule of the knee plays an important role in maintaining the integrity of the knee joint. Pathologies involving the posterior capsule have been implicated in developing flexion contractures. Posterior capsulotomy is a well-studied modality for this issue, performed through either an open or arthroscopic approach. Case Report: A 74-year-old Caucasian male presented with a complex extensor lag of his right knee and an inability to gain full extension either actively or passively. Through the use of standard knee arthroscopy, the authors were able to not only correct his posterior capsular pathology but also address anterior knee lesions. Only the combination of both allowed a full extension of the joint. Conclusion: Posterior capsulotomy of the knee may be carried out successfully and safely through either an open or arthroscopic approach. Arthroscopic capsulotomy is proposed as a safer, minimally invasive option that has been gaining recent favor compared to open approaches.

Core Competencies for Undergraduates in Bioengineering and Biomedical Engineering: Findings, Consequences, and Recommendations.

This paper provides a synopsis of discussions related to biomedical engineering core curricula that occurred at the Fourth BME Education Summit held at Case Western Reserve University in Cleveland, Ohio in May 2019. This summit was organized by the Council of Chairs of Bioengineering and Biomedical Engineering, and participants included over 300 faculty members from 100+ accredited undergraduate programs. This discussion focused on six key questions: QI: Is there a core curriculum, and if so, what are its components? QII: How does our purported core curriculum prepare students for careers, particularly in industry? QIII: How does design distinguish BME/BIOE graduates from other engineers? QIV: What is the state of engineering analysis and systems-level modeling in BME/BIOE curricula? QV: What is the role of data science in BME/BIOE undergraduate education? QVI: What core experimental skills are required for BME/BIOE undergrads? s. Indeed, BME/BIOI core curricula exists and has matured to emphasize interdisciplinary topics such as physiology, instrumentation, mechanics, computer programming, and mathematical modeling. Departments demonstrate their own identities by highlighting discipline-specific sub-specialties. In addition to technical competence, Industry partners most highly value our students' capacity for problem solving and communication. As such, BME/BIOE curricula includes open-ended projects that address unmet patient and clinician needs as primary methods to prepare graduates for careers in industry. Culminating senior design experiences distinguish BME/BIOE graduates through their development of client-centered engineering solutions to healthcare problems. Finally, the overall BME/BIOE curriculum is not stagnant-it is clear that data science will become an ever-important element of our students' training and that new methods to enhance student engagement will be of pedagogical importance as we embark on the next decade.

Novel color additive for chlorine disinfectants corrects deficiencies in spray surface coverage and wet-contact time and checks for correct chlorine concentration.

Bleach sprays suffer from poor surface coverage, dry out before reaching proper contact time, and can be inadvertently over-diluted to ineffective concentrations. Highlight®, a novel color additive for bleach that fades to indicate elapsed contact time, maintained >99.9% surface coverage over full contact time and checked for correct chlorine concentration.

Evaluation of the antimicrobial efficacy and skin safety of a novel color additive in combination with chlorine disinfectants.

OBJECTIVE: A novel color additive colorizes chlorine disinfectants blue to improve visibility and enhance spray surface coverage, and it fades to colorless to indicate elapsed contact time. We investigated its interactions with 3 chlorine disinfectants to determine if the additive would adversely affect the disinfectants' antimicrobial efficacy or skin safety. METHODS: We tested 0.5% sodium hypochlorite, 0.2% calcium hypochlorite, and 0.5% sodium dichloroisocyanurate (NaDCC) alone versus with color additive. An independent laboratory tested efficacy against Staphylococcus aureus, Pseudomonas aeruginosa, Vibrio cholerae, and human coronavirus 229E. An independent laboratory also tested direct skin irritation. RESULTS: Chlorine disinfectants with and without color additive achieved equal levels of efficacy against the tested pathogens. Against S. aureus, 0.5% sodium hypochlorite with and without color additive met Environmental Protection Agency criteria for disinfection success. Against human coronavirus 229E, 0.5% sodium hypochlorite alone failed disinfection success criteria, whereas 0.5% sodium hypochlorite with color additive achieved full viral inactivation (≥4.50 log10 reduction). Against V. cholerae, 0.2% calcium hypochlorite alone and with color additive achieved 5.99 log10 and >6.03 log10 reductions, respectively. Against S. aureus and P. aeruginosa, 0.5% NaDCC with and without color additive achieved >4.9 log10 and >3.54 log10 reductions, respectively. All 3 chlorine disinfectants with color additive tested as negligible skin irritants. CONCLUSIONS: This color additive can be combined with chlorine disinfectants without adversely affecting antimicrobial efficacy or skin safety.

A hands-on course teaching bioinstrumentation through the design and construction of a benchtop cardiac pacemaker.

We have developed a bioinstrumentation course that emphasizes practical application of engineering and biological concepts by having students focus on the development of a single biomedical device: a cardiac pacemaker. In creating their benchtop pacemaker, students learn about and design sensing circuitry, data acquisition and processing code, control system algorithms, and stimulation electronics. They also gain an understanding of cardiac anatomy and electrophysiology. The separate elements of the pacemaker created throughout the semester will be repeatedly tested, re-designed, and integrated with one another, culminating in an emulated pacemaker whose efficacy will be tested on North American bullfrogs. It is hypothesized that the hands-on learning in this course, coupled with the practical application of concepts in the context of a single biomedical device, will enhance students' skills in bioinstrumentation design.

Potential of gallium-based leads for cardiac rhythm management devices.

We propose the use of gallium (Ga), a metal that is liquid at physiological temperatures, or one of its alloys, for use as the conducting material in the leads of implantable pacemakers or cardioverter defibrillators. It is proposed that a liquid conductor will make these leads more pliable and thus less susceptible to fracture in situ. As an initial step towards utilizing liquid gallium in leads, the biocompatibility of Ga was investigated via cytotoxicity, hemocompatibility, and intracutaneous injection testing. Unipolar pacing Ga prototypes were fabricated by adapting existing pacemaker leads. The electrical impedance and pulse transmission ability of these leads were examined. Ga was well tolerated both in vitro and in vivo. Additionally, the Ga prototypes conductors behaved as low magnitude resistances that did not distort pulses as generated by conventional pacemakers. These results indicate that Ga is an appropriate material for implantable cardiac stimulators and will be a focus of our liquid metal prototypes.

LifeShirt acquisition system to monitor ECG from ambulatory swine and the implementation of an arrhythmia detection algorithm.

A wearable cardiopulmonary monitoring system, a LifeShirt, was used to acquire continuous electrocardiograms (ECGs) from ambulatory swine. The animals received intracoronary injections of autologous mesenchymal stem cells, and the LifeShirt was used for long-duration ECG monitoring in pre-defined periods post cell infusion. The system used here was developed for measurements from non-human primates and canines; however, we demonstrated that it could be used to non-invasively measure ECGs from swine without creating undue stress or restricting movement. A MATLAB-based analysis algorithm was developed to automatically detect premature ventricular contractions (PVCs) that arose 8-10 hours after cell delivery with spontaneous resolution 2-3 days post-infusion. Template based cross-correlation was used to detect the PVCs and identify regions of consecutive ventricular rhythm. The final algorithm was highly specific and sensitive when tested on records from the MIT-BIH arrhythmia database. The algorithm was subsequently used to automatically identify and quantify PVCs from over 200 hours of ECG data obtained from nine ambulatory swine.

Computer simulation tool for predicting sound propagation in air-filled tubes with acoustic impedance discontinuities.

A computer tool, based on an acoustic transmission line model, was developed for modeling and predicting sound propagation and reflections in cascaded tube segments. This subroutine considered the number of interconnected tubes, their dimensions and wall properties, as well as medium properties to create a network of cascaded transmission line model segments, from which the impulse response of the network was estimated. Acoustic propagation was examined in air-filled cascaded tube networks and model predictions were compared to measured acoustic pulse responses. The model was able to accurately predict the location and morphology of reflections. The developed code proved to be a useful design tool for applications such as the guidance of catheters through compliant air-filled biological conduits.

Sound propagation in liquid-filled arterial segments: measurements and model predictions.

The efficacy of an acoustic transmission line model (TLM) for predicting distortion that occurs with axial propagation in liquid-filled arterial segments was assessed. Water-filled segments of excised bovine aorta were excited with acoustic pulses and noise to evaluate if velocities, attenuation, and transverse resonance frequencies could be accurately predicted using the TLM. Regions of low acoustic power that were attributed to transverse wall resonance effects were evident in all vessels, but the model generally under-predicted upper frequency limit of the high loss regions. Model-predicted velocities were in fair agreement with measured velocities both in trend and values, however, the energy losses were under-predicted. These preliminary results indicate that the TLM can forecast the general distortion of longitudinal acoustic propagation in liquid-filled arterial segments, yet it requires further refinement to accurately predict dispersive characteristics.