Temperature affects the biomechanical response of in vitro non-human primate lenses during lens stretching.

PURPOSE: To determine the effect of temperature on the accommodative response of non-human primate crystalline lenses during simulated accommodation. METHODS: Eight lenses from 7 cynomolgus monkeys (Macaca fascicularis, ages: 4.5-7.3 years; post-mortem time: 17.0 ± 16.4 h) were mounted in a lens stretcher. Stretching experiments were performed on each lens at 24 °C (room temperature), then the tissue was warmed to 35 °C (intraocular temperature) and the stretching experiments were repeated. The lens diameter, thickness, anterior and posterior surface radii of curvature, optical power, and the stretching force (load) were measured at each stretch position and the linear optomechanical relationships were quantified: load-lens diameter, load-thickness, power-load, load-anterior radius, and load-posterior radius. The rate of change for each parameter was quantified by performing a linear regression. The slopes of the linear regressions were compared at the two temperatures using a paired sample t-test. RESULTS: The average changes in the lens with stretching at 24 °C and 35 °C were: 3.07 ± 0.17 and 2.58 ± 0.15 for load-lens diameter (g/mm), -2.38 ± 0.20 and -2.00 ± 0.32 for load-thickness (g/mm), -13.35 ± 1.21 and -13.75 ± 1.26 for power-load (D/g), 0.41 ± 0.10 and 0.34 ± 0.05 for load-anterior radius of curvature (g/mm), and 1.35 ± 0.24 and 1.31 ± 0.35 for load-posterior radius of curvature (g/mm), respectively. The changes in load-diameter and load-thickness with lens stretching were significantly different for the two temperatures. CONCLUSIONS: Temperature influences the change in lens shape observed during simulated accommodation in non-human primate lenses. These results suggest that lens stretching experiments and other optomechanical measurement techniques on ex vivo crystalline lenses be conducted at 35 °C and that the temperature of the tissue sample be documented and maintained constant to ensure repeatability.

Ultra-Low Contrast Volume Technique for Coronary Angiography - Successful Application in Clinical Setting.

Iodinated contrast media used during cardiac catheterization predispose patients to develop contrast-induced nephropathy. Reducing contrast volumes without impairing the quality of angiographic imaging appears to be a viable solution. We present three cases of patients with chronic kidney disease in which we used an ultra-low contrast volume technique to help minimize contrast exposure risk. This technique uses an automated contrast injection system that can be used during diagnostic or coronary interventional cases and reduces the risk of iatrogenic kidney disease without compromising imaging quality.

Recurrent Ischemic Stroke: A Manifestation of a Sinus of Valsalva Pseudoaneurysm.

An 83-year-old female presented to the emergency department with bilateral eye pain, dizziness, and acute shortness of breath. Her blood pressure (BP) at presentation was 184/93 mmHg. She was admitted for hypertensive emergency and her symptoms improved with BP control. However, during hospitalization, she developed left-sided paresthesia which on investigation was found to be secondary to ischemic stroke. She had two previous aortic mechanical valve replacements for aortic stenosis. Transthoracic echocardiogram revealed a large pseudoaneurysm of the non-coronary sinus of Valsalva that we believe was the cause of her recurrent stroke. A sinus of Valsalva pseudoaneurysm is an uncommon complication of aortic valve replacement surgery which in turn has been associated with aortic rupture, myocardial infarction, and stroke. Our case identifies a situation where sinus of Valsalva pseudoaneurysm predisposed our patient to recurrent ischemic strokes and this should be kept in mind when evaluating a patient with ischemic stroke.

Coronary Artery Perforation Spilling into Right Ventricle: A Rare Complication of Percutaneous Coronary Intervention.

Injury to the coronary circulation during percutaneous interventions is an existent risk. One of these is coronary artery perforation that can have grave consequences. Fortunately, this is rare and overall there is a declining incidence of complications due to technological advances and extensive experience over time. Predictors of coronary artery perforation include the administration of glycoprotein IIb/IIIa inhibitors, the use of hydrophilic guide wires, and the use of noncompliant high-pressure intracoronary balloons. Complex coronary lesions and the presence of total chronic occlusion are additional risk factors. In this paper, we present a rare class III coronary artery perforation with spilling into the right ventricle. Our case exemplifies all the aforementioned risk factors for perforation. The perforation was successfully sealed with a polytetrafluoroethylene covered stent and the patient remained hemodynamically stable.

A Fish Mouth Appearing Perforation of the Native Aortic Valve Due to Streptococcus infantarius subspecies coli.

Infective endocarditis due to Streptococcus infantarius with the subspecies (subsp.) coli is infrequently encountered in healthy humans. This entity is associated with hepatobiliary malignancies and colorectal neoplasia. Here, we report on a unique case of endocarditis associated with S. infantarius subsp. coli in an 80-year-old male with no known risk factors of the infective endocarditis.

Multiple Pulmonary Arteriovenous Malformations: An Unusual Cause of Shortness of Breath and Recurrent Strokes.

OBJECTIVE: To discuss an uncommon case of a patient with multiple pulmonary arteriovenous malformations (PAVMs) presenting with dyspnea on exertion and recurrent strokes. BACKGROUND: A 79-year-old woman with recent onset recurrent cerebrovascular accidents (CVAs) was referred to cardiology for evaluation of dyspnea on exertion. Clinical examination was unrevealing. METHODS: A transthoracic echocardiogram (TTE) with agitated saline was suggestive of an extra-cardiac shunt. Subsequent chest computed tomographic angiography (CTA) demonstrated five large PAVMs. RESULTS: The patient underwent transcatheter coil embolization of the five PAVMs, resulting in marked improvement in dyspnea and resolution of the shunt on bubble study echocardiography. CONCLUSIONS: Although PAVMs are rare, they remain an important entity to consider when evaluating patients with extracardiac shunts. They may present with nonspecific features such as dyspnea on exertion and recurrent CVAs. All patients with multiple PAVMs should undergo thorough skin screening for telangiectasia as well as radiologic imaging to screen for additional AVMs in the liver and brain in order to exclude hereditary hemorrhagic telangiectasia (HHT).

Acute Stent Fracture During Balloon Post Dilation of an Everolimus Eluting Stent.

Coronary artery stent fracture is a well described complication during percutaneous intervention, with rates ranging from 0.84 to 8.4 percent in first generation drug eluting stents. Complications of stent fractures usually present with symptoms of acute coronary syndrome or progressive angina days, months to years after initial implantation. We present a case of an acute stent fracture during post balloon dilation of an everolimus eluting stent at a critical stenosis junction of a saphenous vein graft to the first diagonal of the left anterior descending artery. A shorter oversized drug eluting stent was placed to cover the stent fracture with good angiographic results. To our knowledge, this is the first incidence in literature of an acute stent fracture in a saphenous vein graft.

Implementing the 2013 cholesterol management guidelines into clinical practice.

Although a reduction in atherosclerotic cardiovascular disease (ASCVD) events remains the ultimate goal in cholesterol management, there has been a change in recommended cholesterol management in patients with increased risk. The objective in cholesterol management is no longer reducing low-density lipoprotein (LDL) to a particular target value, but ensuring that patients with the highest ASCVD risk are treated with the most potent statin therapy. The previous practice of statin therapy cessation and routine monitoring for adverse events has also been scrutinized by the recent American Heart Association (AHA)/American College of Cardiology (ACC) guidelines. Identifying patients who are at risk now requires the utilization of a novel tool called the ASCVD pooled cohort calculator. The following article will guide the clinician on implementing the current AHA/ACC guidelines into clinical practice.

Implementing effective hypertensive management--review of the 2014 high blood pressure management guidelines.

The Joint National Committee (JNC 8) hypertension guidelines have modified the blood pressure goals across the spectrum of disease processes and patient characteristics. This article will elucidate these changes and help clinicians improve the clinical care of patients with hypertension. Patients are now conceptually categorized into two different patient populations: those who are at a low- or high-risk of developing atherosclerotic cardiovascular disease (ASCVD) or chronic kidney disease (CKD). A low-risk population comprises patients aged 60 or older who do not have disease processes that enhance ASCVD or CKD disease development. High-risk patients are those with CKD and/or diabetes, and patients less than 60 years of age who remain at risk of future development. The current recommendation for blood-pressure goals in the low- and high-risk population is 150/90 mmHg and 140/90 mmHg, respectively. In all patients considered for antihypertensive therapy, the first line antihypertensive pharmacotherapy should include either a thiazide-type diuretic, calcium channel blocker (CCB), angiotensin-converting enzyme inhibitor (ACEI), or an angiotensin receptor blocker (ARB). Beta blockers no longer have a role as standalone therapy. Thiazide- type diuretics and CCB continue to demonstrate benefit in the African American population and should continue to be considered as first line agents. CKD patients with concomitant hypertension should be treated with an ACE inhibitor or ARB.

A rare large right atrial myxoma with rapid growth rate.

Atrial myxomas are the most common benign intracavitary cardiac neoplasms. They most frequently occur in the left atrium. Right atrial tumors are rare, comprising 20 percent of myxomas achieving an incidence of 0.02 percent. Due to their rarity, right atrial tumor development and associated clinical symptoms has not been well described. The classical clinical triad for the presentation of left atrial myxomas--heart failure, embolic events, and constitutional symptoms--may not be applicable to right sided tumors. Also, natural development of myxoma is not well described, as surgical resection is the common practice. Previously ascribed growth rates of myxomas refer mostly to left atrial ones, as right atrial tumors are rare. We present a case of right atrial myxoma with growth rates exceeding those previously described.

A Phone Consultation Call Line to Support SBIRT in Pediatric Primary Care.

Background: Screening Brief Intervention Referral to Treatment (SBIRT) is recommended as a routine part of pediatric primary care, though managing patients with positive screens is challenging. To address this problem, the state of Massachusetts created a call line staffed by pediatric Addiction Medicine specialists to provide consultations to primary care providers and access to a behavioral health provider specially trained in managing adolescent substance use. Objective: To describe the uptake and outcomes of a consultation call line and virtual counseling for managing substance use disorders (SUD) in pediatric primary care. Methods: Service delivery data from consultations and counseling appointments were captured in an electronic database including substance, medication recommendations, level of care recommendations and number of counseling appointments completed for each patient. Summary data is presented here. Results: In all, there were 407 encounters to 108 unique families, including 128 consultations and 279 counseling visits in a one-year period. The most common substances mentioned by healthcare providers were cannabis (64%), nicotine (20%), alcohol (20%), vaping (9%) and opioids (5%). Management in primary care was recommended for 87 (68%) of the consultations. Medications for SUD treatment were recommended for 69 (54%) consultations including two for opioid use disorder. Conclusion: We found that both a statewide consultation call line and virtual counseling to support SBIRT in pediatric primary care were feasible. The majority of consultations resulted in recommendations for treatment in primary care.

Integrating User Voice in Hearing Care With Focus on Off-Duty Warfighter.

INTRODUCTION: Noise-Induced Hearing Loss (NIHL) is a growing public health concern in the USA and globally because of the emergence of lifestyle preferences and environmental exposures to sound levels exceeding safe listening limits for extended periods of time. In the military, hearing and communication are important for survival and the Department of Defense's Hearing Center of Excellence highlights the importance of protection from NIHL. Issuance of the World health organization safe audio listening standards along with existing U.S. federal and military standards provides a framework for developing an accessible tool for promoting safe listening. METHODS: An App is being proposed for an aggregated assessment of a user's daily sound exposure, through personal audio system and ambient sources and providing tools for managing personal sound exposures. The key elements for development of App features were integration of user voice for functionalities, computations based on global standards, including military, for safe listening and alignment with regulatory standards for Apps. RESULTS: Features of the App are "Track" for audio and ambient exposures, "Compute" for real-time and cumulative exposures vs. safe listening standards, "Alert" for unsafe exposures using visual and haptic, "Inform" for personal exposures vs. safe dose, associated NIHL risk and education, "Choice" for alternatives that can be relatable to personal lifestyle, and "Share" for informing others as determined by the user. App safety is ensured by privacy and cybersecurity regulatory standards. CONCLUSION: The overall goals of the App are to increase NIHL awareness and to empower users to improve personal listening behaviors that can potentially reduce the risk of NIHL.

Residual voltage as an ad-hoc indicator of electrode damage in biphasic electrical stimulation.

Objective.We derive and demonstrate how residual voltage (RV) from a biphasic electrical stimulation pulse can be used to recognize degradation at the electrode-tissue interface.Approach.Using a first order model of the electrode-tissue interface and a rectangular biphasic stimulation current waveform, we derive the equations for RV as well as RV growth over several stimulation pulses. To demonstrate the use of RV for damage detection, we simulate accelerated damage on sputtered iridium oxide film (SIROF) electrodes using potential cycling. RV measurements of the degraded electrodes are compared against standard characterization methods of cyclic voltammetry and electrochemical impedance spectroscopy.Main results.Our theoretical discussion illustrates how an intrinsic RV arises even from perfectly balanced biphasic pulses due to leakage via the charge-transfer resistance. Preliminary data inin-vivorat experiments follow the derived model of RV growth, thereby validating our hypothesis that RV is a characteristic of the electrode-tissue interface. RV can therefore be utilized for detecting damage at the electrode. Our experimental results for damage detection show that delamination of SIROF electrodes causes a reduction in charge storage capacity, which in turn reflects a measurable increase in RV.Significance.Chronically implanted electrical stimulation systems with multi-electrode arrays have been the focus of physiological engineering research for the last decade. Changes in RV over time can be a quick and effective method to identify and disconnect faulty electrodes in large arrays. Timely diagnoses of electrode status can ensure optimal long term operation, and prevent further damage to the tissue near these electrodes.

Hydrophilic Conductive Sponge Sensors for Fast Setup, Low Impedance Bio-potential Measurements.

Low electrode-skin impedance can be achieved if the interface has an electrolytic medium that allows the movement of ions across the interface. Maintaining good physical contact of the sensor with the skin is imperative. We propose a novel hydrophilic conductive sponge interface that encapsulates both of these fundamental concepts into an effective physical realization. Our implementation uses a hydrophilic polyurethane prepolymer doped with conductive carbon nanofibers and cured to form a flexible sponge material that conforms to uneven surfaces, for instance, on parts of the scalp with hair. Our results show that our sponges are able to stay in a hydrated state with a low electrode-skin impedance of around 5kΩ for more than 20 hours. The novelty in our conductive sponges also lies in their versatility: the carbon nanofibers make the electrode effective even when the electrode dries up. The sensors remain conductive with a skin impedance on the order of 20kΩ when dry, which is substantially lower than typical impedance of dry electrodes, and are able to extract alpha wave EEG activity in both wet and dry conditions.

Novel Electrodes for Reliable EEG Recordings on Coarse and Curly Hair.

EEG is a powerful and affordable brain sensing and imaging tool used extensively for the diagnosis of neurological disorders (e.g. epilepsy), brain computer interfacing, and basic neuroscience. Unfortunately, most EEG electrodes and systems are not designed to accommodate coarse and curly hair common in individuals of African descent. In neuroscience studies, this can lead to poor quality data that might be discarded in scientific studies after recording from a broader population set. In clinical diagnoses, it may lead to an uncomfortable and/or emotionally taxing experience, and, in the worst cases, misdiagnosis. Our prior work demonstrated that braiding hair in cornrows to expose the scalp at target locations leads to reduced electrode-skin impedance for existing electrodes. In this work, we design and implement novel electrodes that harness braided hair, and demonstrate that, across time, our electrodes, in conjunction with braiding, lower the impedance further, attaining 10x lower impedance than existing systems.

Low-Cost Carbon Fiber-Based Conductive Silicone Sponge EEG Electrodes.

We propose a novel carbon fiber-based conductive silicone sponge for low electrode-skin impedance EEG recordings. When this sponge is used with water or saline solution, no gel is required, lowering the setup time drastically compared to classical wet electrodes. Moreover, the wet conductive carbon fiber silicone sponges achieve an electrode-skin impedance as low as $2.5\mathrm {k} \Omega $ at 1kHz when wet, making them better than state of the art gel electrodes. Additionally, even as the sponge dries out, it continues to remain conductive and performs as a reliable dry electrode. We demonstrate through experiments that these conductive carbon fiber silicone sponge electrodes, wet or dry, are able to measure alpha wave activity. Our carbon fiber conductive sponge electrodes are low-cost and are highly suitable for designs of portable high density EEG measurement systems.

In vitro characterization of a calcium sulfate/PLLA composite for use as a bone graft material.

A study was conducted to characterize the dissolution, morphology, and chemical composition of a calcium sulfate/poly (L-lactic acid) (CS/PLLA) composite material before and after immersion in simulated body fluid (SBF). Twelve groups of experimental samples were prepared by coating CS pellets 1, 2, 3, or 4 times with one of three concentrations of a PLLA solution and wrapping them in mesh; CS pellets for use as controls were similarly prepared but not coated. The PLLA coating added from 1 to 22% to the weight of experimental pellets; scanning electron microscopy revealed that the coating thickness ranged from 2 to 50 microm depending on the concentration of the coating solution and the number of coatings. All samples were immersed in SBF for up to 97 days. After immersion, the experimental coatings thinned out, small cracks and holes formed in the coating, and the coating became roughened. Mean dissolution rates for each of the 12 CS/PLLA groups were significantly lower than those of uncoated CS pellets; among CS/PLLA groups, dissolution rates varied according to concentration of the coating solution and number of coatings. The half-life of pure CS pellets was 19 days whereas the half-life of CS/PLLA composite pellets ranged from 30 to 70 days. X-ray microprobe analysis of experimental pellets after immersion in SBF revealed that mineralization occurred in the CS portion of these pellets as well as on the coating; most of the mineral was calcium phosphate, most of which was on the coating. Further studies will be required to confirm this composite's promise as a clinically effective osteoconductive material.

The "Chimney Sweep Technique" and Recurrent Coronary Artery Dissections.

We are reporting a case of a 65-year-old female who experienced three ST elevation myocardial infarctions (STEMI) during the course of 3 weeks. The first infarct was related to intramural coronary hematoma that propagated proximally after stenting, the second involved progression of this hematoma with obstruction of the vessel lumen, and the third caused subacute stent thrombosis that required "stent cleaning" using the inflated balloon technique.