Label-free optical detection of bioelectric potentials using electrochromic thin films.

Understanding how a network of interconnected neurons receives, stores, and processes information in the human brain is one of the outstanding scientific challenges of our time. The ability to reliably detect neuroelectric activities is essential to addressing this challenge. Optical recording using voltage-sensitive fluorescent probes has provided unprecedented flexibility for choosing regions of interest in recording neuronal activities. However, when recording at a high frame rate such as 500 to 1,000 Hz, fluorescence-based voltage sensors often suffer from photobleaching and phototoxicity, which limit the recording duration. Here, we report an approach called electrochromic optical recording (ECORE) that achieves label-free optical recording of spontaneous neuroelectrical activities. ECORE utilizes the electrochromism of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) thin films, whose optical absorption can be modulated by an applied voltage. Being based on optical reflection instead of fluorescence, ECORE offers the flexibility of an optical probe without suffering from photobleaching or phototoxicity. Using ECORE, we optically recorded spontaneous action potentials in cardiomyocytes, cultured hippocampal and dorsal root ganglion neurons, and brain slices. With minimal perturbation to cells, ECORE allows long-term optical recording over multiple days.

Dual-Color Optical Recording of Bioelectric Potentials by Polymer Electrochromism.

Optical recording based on voltage-sensitive fluorescent reporters allows for spatial flexibility of measuring from desired cells, but photobleaching and phototoxicity of the fluorescent labels often limit their sensitivity and recording duration. Voltage-dependent optical absorption, rather than fluorescence, of electrochromic materials, would overcome these limitations to achieve long-term optical recording of bioelectrical signals. Electrochromic materials such as PEDOT:PSS possess the property that an applied voltage can either increase or decrease the light absorption depending on the wavelength. In this work, we harness this anticorrelated light absorption at two different wavelengths to significantly improve the signal detection. With dual-color detection, electrical activity from cells produces signals of opposite polarity, while artifacts, mechanical motions, and technical noises are uncorrelated or positively correlated. Using this technique, we are able to optically record cardiac action potentials with a high signal-to-noise ratio, 10 kHz sampling rate, >15 min recording duration, and no time-dependent degradation of the signal. Furthermore, we can reliably perform multiple recording sessions from the same culture for over 25 days.

ERICH3: vesicular association and antidepressant treatment response.

Selective serotonin reuptake inhibitors (SSRIs) are standard of care for major depressive disorder (MDD) pharmacotherapy, but only approximately half of these patients remit on SSRI therapy. Our previous genome-wide association study identified a single-nucleotide polymorphism (SNP) signal across the glutamate-rich 3 (ERICH3) gene that was nearly genome-wide significantly associated with plasma serotonin (5-HT) concentrations, which were themselves associated with SSRI response for MDD patients enrolled in the Mayo Clinic PGRN-AMPS SSRI trial. In this study, we performed a meta-analysis which demonstrated that those SNPs were significantly associated with SSRI treatment outcomes in four independent MDD trials. However, the function of ERICH3 and molecular mechanism(s) by which it might be associated with plasma 5-HT concentrations and SSRI clinical response remained unclear. Therefore, we characterized the human ERICH3 gene functionally and identified ERICH3 mRNA transcripts and protein isoforms that are highly expressed in central nervous system cells. Coimmunoprecipitation identified a series of ERICH3 interacting proteins including clathrin heavy chain which are known to play a role in vesicular function. Immunofluorescence showed ERICH3 colocalization with 5-HT in vesicle-like structures, and ERICH3 knock-out dramatically decreased 5-HT staining in SK-N-SH cells as well as 5-HT concentrations in the culture media and cell lysates without changing the expression of 5-HT synthesizing or metabolizing enzymes. Finally, immunofluorescence also showed ERICH3 colocalization with dopamine in human iPSC-derived neurons. These results suggest that ERICH3 may play a significant role in vesicular function in serotonergic and other neuronal cell types, which might help explain its association with antidepressant treatment response.

Optical Electrophysiology: Toward the Goal of Label-Free Voltage Imaging.

Measuring and monitoring the electrical signals transmitted between neurons is key to understanding the communication between neurons that underlies human perception, information processing, and decision-making. While electrode-based electrophysiology has been the gold standard, optical electrophysiology has opened up a new area in the past decade. Voltage-dependent fluorescent reporters enable voltage imaging with high spatial resolution and flexibility to choose recording locations. However, they exhibit photobleaching as well as phototoxicity and may perturb the physiology of the cell. Label-free optical electrophysiology seeks to overcome these hurdles by detecting electrical activities optically, without the incorporation of exogenous fluorophores in cells. For example, electrochromic optical recording detects neuroelectrical signals via a voltage-dependent color change of extracellular materials, and interferometric optical recording monitors membrane deformations that accompany electrical activities. Label-free optical electrophysiology, however, is in an early stage, and often has limited sensitivity and temporal resolution. In this Perspective, we review the recent progress to overcome these hurdles. We hope this Perspective will inspire developments of label-free optical electrophysiology techniques with high recording sensitivity and temporal resolution in the near future.

Relaxation Dynamics of Hydrated Thymine, Thymidine, and Thymidine Monophosphate Probed by Liquid Jet Time-Resolved Photoelectron Spectroscopy.

The relaxation dynamics of thymine and its derivatives thymidine and thymidine monophosphate are studied using time-resolved photoelectron spectroscopy applied to a water microjet. Two absorption bands are studied; the first is a bright ππ* state which is populated using tunable-ultraviolet light in the range 4.74-5.17 eV and probed using a 6.20 eV probe pulse. By reversing the order of these pulses, a band containing multiple ππ* states is populated by the 6.20 eV pulse and the lower energy pulse serves as the probe. The lower lying ππ* state is found to decay in ∼400 fs in both thymine and thymidine independent of pump photon energy, while thymidine monophosphate decays vary from 670 to 840 fs with some pump energy dependence. The application of a computational quantum mechanical/molecular mechanical scheme at the XMS-CASPT2//CASSCF/AMBER level of theory suggests that conformational differences existing between thymidine and thymidine monophosphate in solution account for this difference. The higher lying ππ* band is found to decay in ∼600 fs in all three cases, but it is only able to be characterized when the 5.17 eV probe pulse is used. Notably, no long-lived signal from an nπ* state can be identified in either experiment on any of the three molecules.

Control of Interfacial Cl2 and N2O5 Reactivity by a Zwitterionic Phospholipid in Comparison with Ionic and Uncharged Surfactants.

Gas-liquid scattering experiments reveal that charge-separated but neutral (zwitterionic) surfactants catalyze the oxidation of dissolved Br- to Br2 by gaseous Cl2 at the surface of a 0.3 M NaBr/glycerol solution. Solutions of NaBr dissolved in glycerol with no surfactant were compared with solutions coated with zwitterionic, cationic, and anionic surfactants at dilute surface concentrations of 1.1 to 1.5 × 1014 cm-2 (less than 65% of maximum chain packing). The zwitterionic phospholipid enhances Cl2 conversion of Br- to Br2 by a factor of 1.61 ± 0.15, in comparison with a 14-fold enhancement by a cationic surfactant (tetrahexylammonium) and a five-fold suppression by an anionic surfactant (dodecyl sulfate). Further studies indicate that even an uncharged surfactant, monododecanoylglycerol, enhances Cl2 → Br2 production. Similar behavior is observed for the oxidation of Br- to Br2 by N2O5; it is just slightly suppressed by the phospholipid and strongly enhanced by the cationic surfactant. Collectively, these results suggest that attractions and repulsions between the negative Br- ions and the positive and negative charges of the surfactant headgroups draw Br- ions to the surface or repel them away. At low coverages, ion-induced dipole and dispersion interactions between the CH2 groups and Br- or Cl2 may also enhance reactivity. These results demonstrate that the hydrocarbon chains of loosely packed surfactants do not necessarily block gas-liquid reactions but that positively charged, and even uncharged, groups can instead facilitate reactions by bringing gas-phase and solution-phase reagents together in the interfacial region.

Lichen Nitidus of the Eyelids.

Lichen nitidus is a rare, idiopathic inflammatory condition that typically presents as small, flat-topped papules on the chest, abdomen, and upper extremities. The lesions are benign and often asymptomatic and self-resolve. The pediatric population is most often affected. The authors report a case of lichen nitidus presenting as isolated bilateral eyelid lesions increasing in number for several years. Eventual excision and antibiotic/steroid ointment prompted regression.

Battlefield Acupuncture vs Ketorolac for Treating Pain in the Emergency Department.

Background: Many patients arrive in the emergency department (ED) with acute pain. Battlefield acupuncture (BFA) uses small, semipermanent acupuncture needles in 5 set points anatomically located on each ear to reduce pain in a few minutes. Pain relief can last months, depending on the pathology of the pain. At the Jesse Brown Veterans Affairs Medical Center (JBVAMC) ED, ketorolac 15 mg is the preferred first-line treatment of acute, noncancer pain. In 2018, BFA was offered first to veterans presenting with acute or acute-on-chronic pain to the ED; however, its effectiveness in pain reduction vs ketorolac has not been evaluated in this patient population. The objective of this study was to determine whether BFA monotherapy was noninferior to ketorolac 15 mg for reducing pain scores in the ED. Methods: This study was a retrospective, electronic chart review of patients who presented to JBVAMC ED with acute pain or acute-on-chronic pain and received ketorolac or BFA. The primary endpoint was the mean difference in the numeric rating scale (NRS) pain score from baseline. Secondary endpoints included the number of patients receiving pain medications, including topical analgesics, at discharge and treatment-related adverse events in the ED. Results: A total of 61 patients were included in the study. Baseline characteristics were similar between the 2 groups except for the average baseline NRS pain score, which was higher in the BFA group (8.7 vs 7.7; P = .02). The mean difference in NRS pain scores from baseline to post-intervention was 3.9 for the BFA group and 5.1 for the ketorolac group. The difference in reducing the NRS pain score between the intervention groups was not statistically significant. No adverse events were observed in either treatment group. Conclusions: For treating acute and acute-on-chronic pain in the ED, BFA did not differ compared with ketorolac 15 mg in NRS pain score reduction. This study's results add to the limited existing literature suggesting that both interventions could result in clinically significant reductions in pain scores for patients presenting to the ED with severe and very severe pain, indicating BFA could be a viable nonpharmacologic treatment option.

Compact Electrochromic Optical Recording of Bioelectric Potentials.

Electrochromic optical recording (ECORE) is a label-free method that utilizes electrochromism to optically detect electrical signals in biological cells with a high signal-to-noise ratio and is suitable for long-term recording. However, ECORE usually requires a large and intricate optical setup, making it relatively difficult to transport and to study specimens on a large scale. Here, we present a Compact ECORE (CECORE) apparatus that drastically reduces the spatial footprint and complexity of the ECORE setup whilst maintaining high sensitivity. An autobalancing differential photodetector automates common-mode noise rejection, removing the need for manually adjustable optics, and a compact laser module conserves space compared to a typical laser mount. The result is a simple, easy-to-use, and relatively low cost system that achieves a sensitivity of 16.7 µV (within a factor of 5 of the shot noise limit), and reliably detects action potentials from Human-induced pluripotent stem cell (HiPSC) derived cardiomyocytes. This setup can be further improved to within 1.5 dB of the shot noise limit by filtering out power-line interference.

Associations of retinal microvascular signs and intracranial large artery disease.

BACKGROUND AND PURPOSE: Intracranial large artery disease (ICLAD) is a major cause of ischemic stroke. Retinal microvascular changes are associated with stroke, including small vessel cerebral disease and extracranial carotid disease. We examined the relationship between ICLAD and retinal microvascular changes. METHODS: This is a prospective cohort of 802 acute ischemic stroke patients. Retinal changes were assessed from photographs by graders masked to clinical data. ICLAD was evaluated using prespecified criteria. RESULTS: ICLAD was not associated with ipsilateral retinal arteriolar/venular caliber, focal arteriolar narrowing, or arteriovenous nicking. Severe enhanced arteriolar light reflex was independently associated with any ICLAD (P=0.006) and severe ICLAD (P<0.001). CONCLUSIONS: Enhanced arteriolar light reflex, but not retinal vessel caliber, was related to ICLAD. These data suggest that retinal microvascular signs have specific associations with large cerebral vessel disease.

Retinal fractals and acute lacunar stroke.

This study aimed to determine whether retinal fractal dimension, a quantitative measure of microvascular branching complexity and density, is associated with lacunar stroke. A total of 392 patients presenting with acute ischemic stroke had retinal fractal dimension measured from digital photographs, and lacunar infarct ascertained from brain imaging. After adjusting for age, gender, and vascular risk factors, higher retinal fractal dimension (highest vs lowest quartile and per standard deviation increase) was independently and positively associated with lacunar stroke (odds ratio [OR], 4.27; 95% confidence interval [CI], 1.49-12.17 and OR, 1.85; 95% CI, 1.20-2.84, respectively). Increased retinal microvascular complexity and density is associated with lacunar stroke.

The effect of tissue wrapping on the expansion of hydrophilic orbital implants.

PURPOSE: Hydrogel implants have been used in hypoplastic orbital expansion. Advantages include insertion through a small incision and expansion without manipulation. The rapid rate of expansion, however, may lead to undesirable outcomes, including implant migration. The authors evaluate the effect of tissue wrapping on expansion of hydrogel implants. METHODS: Three identical hydrogel implants were subjected to one of 3 in vitro interventions: unwrapped control, porcine scleral-wrapped, and porcine fascia-wrapped. Each implant was submerged in normal saline solution. Diameter and volume were measured hourly for 24 hours and then every 4 hours until a plateau or maximal weight was achieved. Measurements were plotted with time as the independent variable and the above measurements as dependent variables. In addition, the best exponential function was graphed and the area under the curve was calculated. RESULTS: Linear plots of data showed a reduction in the rate of diameter and volume expansion for wrapped implants. The areas under the curve of the best-fit exponential function were less for both scleral- and fascia-wrapped implants. Fascia wrapping slowed the rate of volume expansion more than sclera. Also, fascia wrapping seemed to significantly reduce the final implant diameter and volume. CONCLUSIONS: Tissue wrapping slows the rate of expansion of hydrogel spheres in vitro. Fascia wrapping may also reduce the final implant size.

Refractive results with SMILE using lower energy settings in the United States.

PURPOSE: To report the visual and refractive results of small incision lenticule extraction (SMILE) with low energy settings in the United States (US) and to evaluate outcomes for low astigmatism treatment. SETTING: Private clinical practice. DESIGN: Retrospective cohort study. METHODS: This study retrospectively reviewed 462 consecutive eyes that underwent SMILE with lower energy settings. Inclusion criteria included all patients between the ages of 19-39 with myopic astigmatism up to -11.25 diopters (D) spherical equivalent (sphere up to -10.00 D, astigmatism up to -3.00 D), and corrected distance visual acuity of at least 20/25. Eyes with low astigmatism (0.25 D-0.50 D) were also included. Outcome analysis was performed according to the Standard Graphs for Reporting Refractive Surgery at postoperative month (POM) 1, and POM 3-6 when data were available. RESULTS: The mean preoperative spherical equivalent treated was -4.96 ± 2.07; at POM 1, 92% of eyes achieved uncorrected visual acuity (UCVA) of 20/20 or better and maintained visual stability throughout the remainder of the study. At last visit, 431 eyes (93%) achieved UCVA of 20/20 or better, and 461 eyes (99.8%) were 20/25 or better. Ninety-seven (21%) eyes gained at least 1 Snellen line of corrected distance visual acuity and no eyes lost 2 or more lines. Almost all eyes (n = 453, 98%) were within 0.5D of target; 85% of eyes with low astigmatism had ≤0.25 D at last visit compared to 80% of eyes with moderate astigmatism. CONCLUSIONS: SMILE with U.S.-approved low energy settings is safe, predictable, and efficacious and provides patients with a fast visual recovery.

Fractal analysis of the retinal vasculature and chronic kidney disease.

BACKGROUND. Fractal analysis provides a global index of the geometric complexity and optimality of vascular networks. In this study, we investigated the relationship between fractal measurements of the retinal vasculature and chronic kidney disease (CKD). METHODS. This was a population-based case-control study which included participants from the Singapore Prospective Study Program. We identified 261 participants with CKD, defined as estimated glomerular filtration rate of <60 mL/min/1.73 m(2), and 651 controls. The retinal fractal dimension (D(f)) was quantified from digitized fundus photographs using a computer-based programme. RESULTS. The mean D(f) was 1.43 +/- 0.048 in the participants with CKD and 1.44 +/- 0.042 in controls (P = 0.013). Suboptimal D(f) in the lowest (first) and highest (fifth) quintiles were associated with an increased prevalence of CKD after adjusting for age, systolic blood pressure, diabetes and other risk factors [odds ratio (OR) 2.10, 95% confidence interval (CI) 1.15, 3.83 and OR 1.84, 95% CI 1.06, 3.17; compared to the fourth quintile, respectively). This association was present even in participants without diabetes or hypertension. CONCLUSIONS. Our study found that an abnormal retinal vascular network is associated with an increased risk of CKD, supporting the hypothesis that deviations from optimal microvascular architecture may be related to kidney damage.

Retinal vascular caliber and extracranial carotid disease in patients with acute ischemic stroke: the Multi-Centre Retinal Stroke (MCRS) study.

BACKGROUND AND PURPOSE: Previous studies show that both retinal vascular caliber and carotid disease predict incident stroke in the general population, but the exact relationship between these 2 microvascular and macrovascular structural risk factors is unclear. We studied the relationship between retinal vascular caliber and carotid disease in patients presenting with acute ischemic stroke. METHODS: We conducted a cross-sectional study of patients with acute ischemic stroke recruited from 3 centers (Melbourne, Sydney, Singapore). The caliber of retinal arterioles and venules was measured from digital retinal photographs. Severe extracranial carotid disease was defined as stenosis >or=75% or occlusion determined by carotid Doppler using North American Symptomatic Carotid Endarterectomy Trial-based criteria. RESULTS: Among the 1029 patients with acute stroke studied, 7% of the population had severe extracranial carotid disease. Retinal venular caliber was associated with ipsilateral severe carotid disease (P<0.001 in multivariate models). Patients with wider retinal venular caliber were more likely to have severe ipsilateral carotid disease (multivariable-adjusted OR, 3.81; 95% CI, 1.80 to 8.07, comparing the largest and smallest venular caliber quartiles). The retinal venular caliber-carotid disease association remained significant in patients with large artery stroke. CONCLUSIONS: In patients with acute stroke, retinal venular widening was strongly associated with ipsilateral severe extracranial carotid disease. Our findings suggest concomitant retinal and cerebral microvascular disease may be present in patients with carotid stenosis or occlusion disease. The pathogenesis of stroke due to carotid disease may thus be partially mediated by microvascular disease.

Synthesis and PKCtheta inhibitory activity of a series of 5-vinyl phenyl sulfonamide-3-pyridinecarbonitriles.

A series of 5-vinyl phenyl sulfonamide-3-pyridinecarbonitriles were prepared and evaluated as PKCtheta inhibitors. Optimization resulted in the identification of compound 15 with an IC(50) value 0.44 nM for the inhibition of PKCtheta with 150-fold selectivity over PKCdelta.

Aminopyrazole Carboxamide Bruton's Tyrosine Kinase Inhibitors. Irreversible to Reversible Covalent Reactive Group Tuning.

Potent covalent inhibitors of Bruton's tyrosine kinase (BTK) based on an aminopyrazole carboxamide scaffold have been identified. Compared to acrylamide-based covalent reactive groups leading to irreversible protein adducts, cyanamide-based reversible-covalent inhibitors provided the highest combined BTK potency and EGFR selectivity. The cyanamide covalent mechanism with BTK was confirmed through enzyme kinetic, NMR, MS, and X-ray crystallographic studies. The lead cyanamide-based inhibitors demonstrated excellent kinome selectivity and rat pharmacokinetic properties.

Corneal edema and keratitis following selective laser trabeculoplasty.

PURPOSE: To describe three cases of keratitis following Selective Laser Trabeculoplasty (SLT). OBSERVATIONS: Three females with a history of glaucoma presented with corneal edema, keratitis (endothelial, epithelial) and decreased visual acuity shortly after SLT. There was variable resolution of symptoms after starting treatment with oral antiherpetics and topical steroids. CONCLUSIONS AND IMPORTANCE: With the increase in usage of SLT as a treatment for glaucoma and subsequent reports of keratitis, it is imperative for ophthalmic surgeons to be aware of herpes simplex as a possible risk factor. Prompt treatment with antivirals and steroids can potentially prevent scarring and permanent damage to the cornea.

Rapidly progressive cataract formation associated with non-small-cell lung cancer therapy.

We report 6 patients who developed rapidly progressive hypermature cataracts after starting treatment with rociletinib, a non-small-cell lung cancer therapy with known side effects of hyperglycemia, fatigue, and prolonged QT. Early cataract detection and surgery may prevent complications during future cataract removal. Although rociletinib development has been suspended, there are patients who have been treated and will continue to be treated with this medication based on their physician's judgment. These physicians should know about the potential for rapid vision loss due to cataracts as a manageable side effect. FINANCIAL DISCLOSURE: Neither author has a financial or proprietary interest in any material or method mentioned.