The effect of sex and age on ex vivo cardiac electrophysiology: insight from a guinea pig model.

Highlighting the importance of sex as a biological variable, we recently reported sex differences in guinea pig in vivo electrocardiogram (ECG) measurements. However, substantial inconsistencies exist in this animal model, with conflicting reports of sex-specific differences in cardiac electrophysiology observed in vivo and in vitro. Herein, we evaluated whether sexual dimorphism persists in ex vivo preparations, using an isolated intact heart preparation. Pseudo-ECG recordings were collected in conjunction with dual optical mapping of transmembrane voltage and intracellular calcium from Langendorff-perfused hearts. In contrast to our in vivo results, we did not observe sex-specific differences in ECG parameters collected from isolated hearts. Furthermore, we observed significant age-specific differences in action potential duration (APD) and Ca2+ transient duration (CaD) during both normal sinus rhythm (NSR) and in response to dynamic pacing but only a modest sex-specific difference in CaD30. Similarly, the alternans fluctuation coefficient, conduction velocity during sinus rhythm or in response to pacing, and electrophysiology parameters (atrioventricular nodal effective refractory period, Wenckebach cycle length) were comparable between males and females. Results of our study suggest that the observed sex-specific differences in in vivo ECG parameters from guinea pigs are diminished in ex vivo isolated heart preparations, although age-specific patterns are prevalent. To assess sex as a biological variable in cardiac electrophysiology, a comprehensive approach may be necessary using both in vitro measurements from cardiomyocyte or intact heart preparations with secondary follow-up in vivo studies.NEW & NOTEWORTHY We evaluated whether the guinea pig heart has intrinsic sex-specific differences in cardiac electrophysiology. Although we observed sex-specific differences in in vivo ECGs, these differences did not persist ex vivo. Using a whole heart model, we observed similar APD, CaD, conduction velocity, and alternans susceptibility in males and females. We conclude that sex-specific differences in guinea pig cardiac electrophysiology are likely influenced by the in vivo environment and less dependent on the intrinsic electrical properties of the heart.

Pinus ponderosa: A checkered past obscured four species.

PREMISE OF THE STUDY: Molecular genetic evidence can help delineate taxa in species complexes that lack diagnostic morphological characters. Pinus ponderosa (Pinaceae; subsection Ponderosae) is recognized as a problematic taxon: plastid phylogenies of exemplars were paraphyletic, and mitochondrial phylogeography suggested at least four subdivisions of P. ponderosa. These patterns have not been examined in the context of other Ponderosae species. We hypothesized that putative intraspecific subdivisions might each represent a separate taxon. METHODS: We genotyped six highly variable plastid simple sequence repeats in 1903 individuals from 88 populations of P. ponderosa and related Ponderosae (P. arizonica, P. engelmannii, and P. jeffreyi). We used multilocus haplotype networks and discriminant analysis of principal components to test clustering of individuals into genetically and geographically meaningful taxonomic units. KEY RESULTS: There are at least four distinct plastid clusters within P. ponderosa that roughly correspond to the geographic distribution of mitochondrial haplotypes. Some geographic regions have intermixed plastid lineages, and some mitochondrial and plastid boundaries do not coincide. Based on relative distances to other species of Ponderosae, these clusters diagnose four distinct taxa. CONCLUSIONS: Newly revealed geographic boundaries of four distinct taxa (P. benthamiana, P. brachyptera, P. scopulorum, and a narrowed concept of P. ponderosa) do not correspond completely with taxonomies. Further research is needed to understand their morphological and nuclear genetic makeup, but we suggest that resurrecting originally published species names would more appropriately reflect the taxonomy of this checkered classification than their current treatment as varieties of P. ponderosa.

Comparative cardiotoxicity assessment of bisphenol chemicals and estradiol using human induced pluripotent stem cell-derived cardiomyocytes.

Bisphenol A (BPA) is commonly used to manufacture consumer and medical-grade plastics. Due to health concerns, BPA substitutes are being incorporated-including bisphenol S (BPS) and bisphenol F (BPF)-without a comprehensive understanding of their toxicological profile. Previous studies suggest that bisphenol chemicals perturb cardiac electrophysiology in a manner that is similar to 17ß-estradiol (E2). We aimed to compare the effects of E2 with BPA, BPF, and BPS using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM). Cardiac parameters were evaluated using microelectrode array (MEA) technology and live-cell fluorescent imaging. Cardiac metrics remained relatively stable after exposure to nanomolar concentrations (1-1000 nM) of E2, BPA, BPF, or BPS. At higher micromolar concentrations, chemical exposures decreased the depolarization spike amplitude, and shortened the field potential, action potential duration, and calcium transient duration (E2 ≥ BPA ≥ BPF ≫ BPS). Cardiomyocyte physiology was largely undisturbed by BPS. BPA-induced effects were exaggerated when coadministered with an L-type calcium channel (LTCC) antagonist or E2, and reduced when coadministered with an LTCC agonist or an estrogen receptor alpha antagonist. E2-induced effects were not exaggerated by coadministration with an LTCC antagonist. Although the observed cardiac effects of E2 and BPA were similar, a few distinct differences suggest that these chemicals may act (in part) through different mechanisms. hiPSC-CM are a useful model for screening cardiotoxic chemicals, nevertheless, the described findings should be validated using a more complex ex vivo and/or in vivo model.

Comparative cardiotoxicity assessment of bisphenol chemicals and estradiol using human induced pluripotent stem cell-derived cardiomyocytes.

Background: Bisphenol A (BPA) is commonly used to manufacture consumer and medical-grade plastics. Due to health concerns, BPA substitutes are being incorporated - including bisphenol S (BPS) and bisphenol F (BPF) - without a comprehensive understanding of their toxicological profile. Objective: Previous studies suggest that bisphenol chemicals perturb cardiac electrophysiology in a manner that is similar to 17ß-estradiol (E2). We aimed to compare the effects of E2 with BPA, BPF, and BPS using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM). Methods: Cardiac parameters were evaluated using microelectrode array (MEA) technology and live-cell fluorescent imaging at baseline and in response to chemical exposure (0.001-100 µM). Results: Cardiac metrics remained relatively stable after exposure to nanomolar concentrations (1-1,000 nM) of E2, BPA, BPF, or BPS. At higher micromolar concentrations, chemical exposures resulted in a decrease in the depolarizing spike amplitude, shorter field potential and action potential duration, shorter calcium transient duration, and decrease in hiPSC-CM contractility (E2 > BPA > BPF >> BPS). Cardiomyocyte physiology was largely undisturbed by BPS exposure. BPA-induced effects were exaggerated when co-administered with an L-type calcium channel antagonist (verapamil) or E2 - and reduced when co-administered with an L-type calcium channel agonist (Bay K8644) or an estrogen receptor alpha antagonist (MPP). E2-induced effects generally mirrored those of BPA, but were not exaggerated by co-administration with an L-type calcium channel antagonist. Discussion: Collectively across multiple cardiac endpoints, E2 was the most potent and BPS was the least potent disruptor of hiPSC-CM function. Although the observed cardiac effects of E2 and BPA were similar, a few distinct differences suggest that these chemicals may act (in part) through different mechanisms. hiPSC-CM are a useful model for screening cardiotoxic chemicals, nevertheless, the described in vitro findings should be validated using a more complex ex vivo and/or in vivo model.

Characteristics of Bisphenol Cardiotoxicity: Impaired Excitability, Contractility, and Relaxation.

Bisphenol a (BPA) is a high production volume chemical that is frequently used to manufacture epoxy resins and polycarbonate plastics. BPA-containing products are now pervasive, and as a result, biomonitoring studies report widespread exposure in > 90% of adults, adolescents, and children. Both epidemiological and experimental studies have reported associations between BPA exposure and adverse cardiovascular health outcomes. With increasing concerns regarding BPA exposure, a few structurally similar bisphenol chemicals have been introduced as replacements, including bisphenol s (BPS) and bisphenol f (BPF). In accordance with the recently established "Key characteristics of cardiovascular toxicants", we reviewed the literature to highlight the immediate effects of bisphenol chemicals on (1) cardiac excitability, and (2) contractility and relaxation. BPA inhibits key cardiac ion channels, impairs cardiac excitability, and acts as a more potent inhibitor as compared to BPF and BPS. Through the inhibition of calcium current, some studies report that bisphenol chemicals can act as negative inotropic agents. Yet, others suggest that low dose exposures may increase contractility and precipitate triggered arrhythmias via the phosphorylation of key calcium handling proteins. Accordingly, we propose additional considerations for future work to comprehensively address the cardiac safety profile of BPA, as compared to replacement chemicals.

Demographic and Methodological Heterogeneity in Electrocardiogram Signals From Guinea Pigs.

Electrocardiograms (ECG) are universally used to measure the electrical activity of the heart; however, variations in recording techniques and/or subject demographics can affect ECG interpretation. In this study, we investigated variables that are likely to influence ECG metric measurements in cardiovascular research, including recording technique, use of anesthesia, and animal model characteristics. Awake limb lead ECG recordings were collected in vivo from adult guinea pigs using a platform ECG system, while recordings in anesthetized animals were performed using both a platform and needle ECG system. We report significant heterogeneities in ECG metric values that are attributed to methodological differences (e.g., ECG lead configuration, ECG recording platform, presence or absence of anesthesia) that persist even within the same cohort of animals. Further, we report that variability in animal demographics is preserved in vivo ECG recordings-with animal age serving as a significant contributor, while sex-specific influences were less pronounced. Methodological approaches and subject demographics should be fully considered when interpreting ECG values in animal models, comparing datasets between studies, or developing artificial intelligence algorithms that utilize an ECG database.

Bisphenol S and Bisphenol F Are Less Disruptive to Cardiac Electrophysiology, as Compared With Bisphenol A.

Bisphenol A (BPA) is a high-production volume chemical used to manufacture consumer and medical-grade plastic products. Due to its ubiquity, the general population can incur daily environmental exposure to BPA, whereas heightened exposure has been reported in intensive care patients and industrial workers. Due to health concerns, structural analogs are being explored as replacements for BPA. This study aimed to examine the direct effects of BPA on cardiac electrophysiology compared with recently developed alternatives, including BPS (bisphenol S) and BPF (bisphenol F). Whole-cell voltage-clamp recordings were performed on cell lines transfected to express the voltage-gated sodium channel (Nav1.5), L-type voltage-gated calcium channel (Cav1.2), or the rapidly activating delayed rectifier potassium channel (hERG). Cardiac electrophysiology parameters were measured using human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) and intact, whole rat heart preparations. BPA was the most potent inhibitor of fast/peak (INa-P) and late (INa-L) sodium channel (IC50 = 55.3, 23.6 µM, respectively), L-type calcium channel (IC50 = 30.8 µM), and hERG channel current (IC50 = 127 µM). Inhibitory effects on L-type calcium channels were supported by microelectrode array recordings, which revealed a shortening of the extracellular field potential (akin to QT interval). BPA and BPF exposures slowed atrioventricular (AV) conduction and increased AV node refractoriness in isolated rat heart preparations, in a dose-dependent manner (BPA: +9.2% 0.001 µM, +95.7% 100 µM; BPF: +20.7% 100 µM). BPS did not alter any of the cardiac electrophysiology parameters tested. Results of this study demonstrate that BPA and BPF exert an immediate inhibitory effect on cardiac ion channels, whereas BPS is markedly less potent. Additional studies are necessary to fully elucidate the safety profile of bisphenol analogs on the heart.

KairoSight: Open-Source Software for the Analysis of Cardiac Optical Data Collected From Multiple Species.

Cardiac optical mapping, also known as optocardiography, employs parameter-sensitive fluorescence dye(s) to image cardiac tissue and resolve the electrical and calcium oscillations that underly cardiac function. This technique is increasingly being used in conjunction with, or even as a replacement for, traditional electrocardiography. Over the last several decades, optical mapping has matured into a "gold standard" for cardiac research applications, yet the analysis of optical signals can be challenging. Despite the refinement of software tools and algorithms, significant programming expertise is often required to analyze large optical data sets, and data analysis can be laborious and time-consuming. To address this challenge, we developed an accessible, open-source software script that is untethered from any subscription-based programming language. The described software, written in python, is aptly named "KairoSight" in reference to the Greek word for "opportune time" (Kairos) and the ability to "see" voltage and calcium signals acquired from cardiac tissue. To demonstrate analysis features and highlight species differences, we employed experimental datasets collected from mammalian hearts (Langendorff-perfused rat, guinea pig, and swine) dyed with RH237 (transmembrane voltage) and Rhod-2, AM (intracellular calcium), as well as human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) dyed with FluoVolt (membrane potential), and Fluo-4, AM (calcium indicator). We also demonstrate cardiac responsiveness to ryanodine (ryanodine receptor modulator) and isoproterenol (beta-adrenergic agonist) and highlight regional differences after an ablation injury. KairoSight can be employed by both basic and clinical scientists to analyze complex cardiac optical mapping datasets without requiring dedicated computer science expertise or proprietary software.

Outcomes of laceration suture repair in the emergency department.

OBJECTIVE: To assess patient satisfaction with laceration management, post-ED care, cosmesis and complication rates. METHODS: We undertook a prospective observational study of adult patients with lacerations sutured in two EDs over a 4-month period. ED data included participant demographics, laceration characteristics and management. A telephone survey was undertaken approximately 14 days post-ED discharge. Patient satisfaction with post-ED pain management, advice on wound care and follow up, overall management and wound cosmesis were evaluated using a six-item satisfaction scale (very dissatisfied to very satisfied). Details of wound infection, dehiscence and suture failure were recorded. RESULTS: Eighty-nine patients participated. The number (% [95% confidence interval]) of patients very satisfied with their laceration management were: post-ED pain management 55 (62.5% [51.5-72.4]), wound care advice 51 (57.3% [46.4-67.6]), follow-up advice 39 (43.8% [33.5-54.7]), overall management 61 (68.5% [57.7-77.7]) and cosmetic appearance 46 (51.7% [40.9-62.3]). Infection, dehiscence and suture failure occurred in 5 (5.6%), 8 (9.0%) and 8 (9.0%) cases, respectively. These complications were not associated with being very satisfied overall (P = 0.96). Patients very satisfied with post-ED pain management, wound care advice, follow-up advice or wound cosmesis were much more likely to be very satisfied overall (P < 0.001). CONCLUSIONS: Most patients are very satisfied with their laceration management. However, there is scope for improvement, especially for follow-up and wound care advice. Complications are infrequent and not associated with overall satisfaction.

Bisphenols and phthalates: Plastic chemical exposures can contribute to adverse cardiovascular health outcomes.

Phthalates and bisphenols are high production volume chemicals that are used in the manufacturing of consumer and medical products. Given the ubiquity of bisphenol and phthalate chemicals in the environment, biomonitoring studies routinely detect these chemicals in 75-90% of the general population. Accumulating evidence suggests that such chemical exposures may influence human health outcomes, including cardiovascular health. These associations are particularly worrisome for sensitive populations, including fetal, infant and pediatric groups-with underdeveloped metabolic capabilities and developing organ systems. In the presented article, we aimed to review the literature on environmental and clinical exposures to bisphenols and phthalates, highlight experimental work that suggests that these chemicals may exert a negative influence on cardiovascular health, and emphasize areas of concern that relate to vulnerable pediatric groups. Gaps in our current knowledge are also discussed, so that future endeavors may resolve the relationship between chemical exposures and the impact on pediatric cardiovascular physiology.

Differentially expressed genes during malting and correlation with malting quality phenotypes in barley (Hordeum vulgare L.).

Breeding for malting quality is an important goal of malting barley breeding programs. Malting quality is a complex phenotype that combines a large number of interrelated components, each of which shows complex inheritance. Currently, only a few genes involved in determining malting quality have been characterized. We combined transcript profiling with phenotypic correlations to identify candidate genes for malting quality. The Barley1 GeneChip array containing 22,792 probe sets was used to conduct transcript profiling of genes expressed in several different stages of malting of four malting cultivars. Genes that were differentially expressed in comparisons between different malting stages relative to ungerminated seed, as well as in comparisons between malting cultivars in the same malting stage were identified. Correlation analysis of 723 differentially expressed genes with malting quality phenotypes showed that 11-102 of these genes correlated with six malting quality phenotypes. Genes involved in carbohydrate metabolism were among the positively correlated genes. Genes for protein and lipid metabolism, cell wall organization and biogenesis, and genes involved in stress and defense response also correlated with malting quality phenotypes. Expressed sequence tags (ESTs) were generated from a 'malting-gene enriched' cDNA library made by suppression subtractive hybridization between malted and ungerminated seeds of 'Morex'. Eleven percent of the ESTs had no significant homology with sequences in the databases, suggesting that there may be other malting-related genes not represented in the barley gene chip array. The results provide candidate genes for malting quality phenotypes that need to be functionally validated.

Bevacizumab Versus Ranibizumab in the Treatment of Macular Edema Due to Retinal Vein Occlusion: 6-Month Results of the CRAVE Study.

BACKGROUND AND OBJECTIVE: To compare efficacy of monthly treatment with bevacizumab or ranibizumab for macular edema due to retinal vein occlusion. PATIENTS AND METHODS: Randomized, multicenter, comparative trial (ClinicalTrials.gov identifier: NCT01428388). Participants were randomized 1:1 to receive monthly treatment with bevacizumab or ranibizumab. The primary outcome was change in central foveal thickness at 6 months compared to baseline. RESULTS: The trial randomized 98 patients to treatment with bevacizumab or ranibizumab. At 6 months, there were no differences in change in central foveal thickness between groups (bevacizumab: mean reduction of 212.6 µm, 95% confidence interval [CI], -288.3 to -137.0; ranibizumab: mean reduction of 243.8 µm, 95% CI, -309.6 to -178.0; P=.72, analysis of variance [ANOVA]). Both groups showed similar functional outcomes (bevacizumab: 0.33 logMAR gain, 95% CI, -0.47 to -0.18; ranibizumab: 0.34 logMAR gain, 95% CI, -0.45 to -0.23; P=.38, ANOVA). CONCLUSION: In the treatment of retinal vein occlusion, bevacizumab and ranibizumab have similar effects on reducing macular thickness and improving visual acuity.

Case-control study of endophthalmitis after cataract surgery comparing scleral tunnel and clear corneal wounds.

PURPOSE: To study the possible association between clear corneal incision with or without placement of a suture during cataract extraction and postoperative endophthalmitis. DESIGN: Retrospective, comparative, case-controlled study. METHODS: Thirty-eight patients treated for culture-positive, acute post-cataract surgery endophthalmitis, and 371 randomly selected control patients who underwent uncomplicated cataract surgery in the referring community were studied. Incision type and use of suture during cataract surgery of endophthalmitis patients were compared with the controls. The data were analyzed using logistic regression methods. RESULTS: Of the 38 patients with endophthalmitis, 17 patients (45%) had clear corneal incisions and 21 patients (55%) had a scleral tunnel incision. In 371 controls, 76 patients (20%) had clear corneal incisions and 295 patients (80%) had scleral tunnel incisions. Clear corneal incision was associated with a threefold greater risk of endophthalmitis than was scleral tunnel incision (Odds Ratio, 3.36, 95% Confidence Interval = 1.67 to 6.78). The type of incision was significant (chi(2) = 11.53, P =.0007); a clear corneal incision was more frequently associated with endophthalmitis. A subgroup analysis revealed that the presence or absence of a suture was not significant (chi(2) = 1.31, P =.2524). CONCLUSIONS: In this retrospective, case-controlled study, clear corneal incisions were found to be a statistically significant risk factor for acute post-cataract surgery endophthalmitis when compared with scleral tunnel incisions.

Ranibizumab versus photodynamic therapy for presumed ocular histoplasmosis syndrome.

BACKGROUND AND OBJECTIVE: To evaluate the efficacy of ranibizumab in the treatment of choroidal neovascularization secondary to presumed ocular histoplasmosis syndrome. PATIENTS AND METHODS: Patients enrolled in the ranibizumab group received a monthly intravitreal injection of 0.5 mg of ranibizumab. Patients in the photodynamic therapy (PDT) group received a quarterly dosing of intravenous verteporfin coupled with PDT. RESULTS: Mean change in ETDRS visual acuity at 1 year was 19.6 letters in the ranibizumab group versus 21 letters in the PDT group. All patients in the PDT group required rescue ranibizumab therapy. Four of five patients (80%) in the ranibizumab group and one of two patients (50%) in the PDT group showed a greater than 15 letter gain at 1 year. CONCLUSION: Ranibizumab appears to be a safe and effective treatment option for choroidal neovascularization secondary to the presumed ocular histoplasmosis syndrome.