Tissue Usage Preference and Intrinsically Disordered Region Remodeling of Alternative Splicing Derived Proteoforms in the Heart.

A computational analysis of mass spectrometry data was performed to uncover alternative splicing derived protein variants across chambers of the human heart. Evidence for 216 non-canonical isoforms was apparent in the atrium and the ventricle, including 52 isoforms not documented on SwissProt and recovered using an RNA sequencing derived database. Among non-canonical isoforms, 29 show signs of regulation based on statistically significant preferences in tissue usage, including a ventricular enriched protein isoform of tensin-1 (TNS1) and an atrium-enriched PDZ and LIM Domain 3 (PDLIM3) isoform 2 (PDLIM3-2/ALP-H). Examined variant regions that differ between alternative and canonical isoforms are highly enriched with intrinsically disordered regions. Moreover, over two-thirds of such regions are predicted to function in protein binding and RNA binding. The analysis here lends further credence to the notion that alternative splicing diversifies the proteome by rewiring intrinsically disordered regions, which are increasingly recognized to play important roles in the generation of biological function from protein sequences.

Topical Ophthalmic Anesthetic Use for Sterile Corneal Abrasion in the Emergency Department.

OBJECTIVES: Investigate current treatment and prescription practices of topical ophthalmic anesthetic agents (TOAAs) in emergency departments (EDs) across the United States to understand how these encounters may affect ocular health. METHODS: A six question survey regarding the use of topical ophthalmic anesthetics was completed by 73 emergency medicine (EM) physicians across 34 states through the American College of Emergency Physicians (ACEP) Emergency Medicine Practices Research Network (EMPRN). RESULTS: The survey was completed by 73 EM physicians. The majority indicated treating eye-related complaints frequently and comfort using (TOAAs) for pain control in sterile corneal abrasion. Over half of respondents indicated never discharging a patient from the ED with a prescription for TOAAs. The consensus for patient instructions included offering a short course (<48 hr) of treatment. Furthermore, 96% of respondents indicated that they would not prescribe refills for TOAAs, mostly due to concern regarding corneal damage. CONCLUSIONS: Despite demonstrable concern regarding the use of TOAAs and risk of corneal damage, a minority of EM physicians continue to prescribe these agents in the treatment of sterile corneal abrasion, which poses risks to visual health. Ophthalmologists have begun to advocate for decreased availability of TOAAs in settings such as the ED.

Selection and characterisation of weakly coordinating solvents for semiconductor electrodeposition.

Weakly coordinating solvents, such as dichloromethane, have been shown to be attractive for the electrodeposition of functional p-block compound and alloy semiconductors for electronic device applications. In this work the use of solvent descriptors to define weakly coordinating solvents and to identify new candidates for electrochemical applications is discussed. A set of solvent selection criteria are identified based on Kamlet and Taft's π*, α and ß parameters: suitable solvents should be polar (π* ≥ 0.55), aprotic and weakly coordinating (α and ß ≤ 0.2.). Five candidate solvents were identified and compared to dichloromethane: trifluorotoluene, o-dichlorobenzene, p-fluorotoluene, chlorobenzene and 1,2-dichloroethane. The solvents were compared using a suite of measurements including electrolyte voltammetric window, conductivity, and differential capacitance, and the electrochemistry of two model redox couples (decamethylferrocene and cobaltocenium hexafluorophosphate). Ion pairing is identified as a determining feature in weakly coordinating solvents and the criteria for selecting a solvent for electrochemistry is considered. o-dichlorobenzene and 1,2-dichloroethane are shown to be the most promising of the five for application to electrodeposition because of their polarity.

Impact of glaucoma on executive function and visual search.

PURPOSE: Executive function and visual search are linked to a number of activities of daily living including driving and mobility. Using a computerised version of the Trail Making Test B (TMT-B), we compared the executive function and visual search ability of older adults with glaucoma to age-similar controls and identified which visual function tests best predict TMT-B performance. Novel low-contrast and shifting-target variations of the test were incorporated to explore the effects of different levels of test complexity. METHODS: Thirty-one older adults with mild to moderate glaucoma (mean age = 71.2 years [SD 6.9]; better-eye mean deviation [MD]: median = -1.9 dB [IQR = -1.2 to 0.4], worse-eye MD: median = -11.1 dB [IQR = -14.0 to -7.7]) and 24 age-similar controls (mean age = 71.9 years [SD 6.6]) with normal vision participated. The groups were matched in age, sex, and cognitive status (mini-mental state examination [MMSE]). Participants underwent measurements of visual acuity, contrast sensitivity (CS), visual fields, and visual processing speeds using the useful field-of-view (UFoV). Participants then completed four variations of a computerised TMT-B test, with different levels of complexity based on target contrast (high/low-contrast) and shifts in target position (fixed/shifting locations). Linear mixed-effect models were used to explore the effects of group, target contrast and shift on TMT-B completion time. RESULTS: The glaucoma group took 17.3s longer than controls to complete the TMT-B (P = 0.028). All participants took 6.5s longer to complete the low- compared to the high-contrast tests (P = 0.012), and 10.6s longer for the shifting TMT-B compared to the fixed version (P < 0.001). There was no interaction effect between group, contrast, or target shift on completion time. Across all tests and participant groups, longer completion time was associated with slower UFoV processing speeds (divided attention: P = 0.003; selective attention: P = 0.006). Poorer CS was associated with longer completion times for the low (P = 0.007), but not the high-contrast tests. CONCLUSIONS: Our findings suggest that older adults with mild to moderate glaucoma have poorer visual search ability and executive function relative to controls. However, decreasing target contrast or shifting target position did not exacerbate the effects of glaucomatous visual impairment on performance. The UFoV was a strong predictor of TMT-B performance.

Harnessing topographical & biochemical cues to enhance elastogenesis by paediatric cells for cardiovascular tissue engineering applications.

The development of tissue-engineered vascular grafts (TEVGs) with a biomimetic extracellular matrix (ECM) structure, including a mature elastic network, remains a key challenge for the production of grafts with long-term functionality. The aim of this study was to investigate the influence of aligned nanofiber substrates on ECM protein synthesis by neonatal smooth muscle cells (SMCs), and to examine the combined effects of this topographical cue in conjunction with transforming growth factor beta-1 (TGF-ß1) - a biochemical elastogenic promoter. Glass coverslips were coated in electrospun fibrinogen nanofibers (average diameter < 500 nm) with either a randomly-orientated or aligned topography. Human umbilical artery smooth muscle cells (hUASMCs) were cultured on the electrospun substrates for 7 and 14 days, with or without a 2 ng/ml TGF-ß1 supplement. The ECM structure was analysed using immunohistochemistry and the quantity of secreted elastin in the cell layer was measured using a dye-binding assay. Aligned fiber substrates induced a directed orientation of both the seeded cells and cell-synthesized ECM fibers. Cells cultured on aligned fibers exhibited a significant increase in the expression of phenotypic contractile proteins, as well as increases in the secreted elastin content of the cell layer, compared to cells cultured on randomly-orientated substrates. TGF-ß1 supplementation was shown to synergistically increase secreted elastin from cells cultured on aligned fiber substrates (p < 0.05). Aligned nanofiber scaffolds can be used to direct cellular orientation, elastin-related protein synthesis and cell phenotype, and consequently there is potential for their application in the development of TEVGs as part of a multi-pronged strategy to promote elastic fiber formation.

Development of Pulmonary Hypertension During Treatment with Diazoxide: A Case Series and Literature Review.

Congenital hyperinsulinism (CHI) is the most common cause of persistent hypoglycemia in infancy. The mainstay of medical management for CHI is diazoxide. Diazoxide inhibits insulin release from the pancreas, but also causes smooth muscle relaxation and fluid retention so it is typically given with chlorothiazide. In July 2015, the FDA issued a drug safety communication warning that pulmonary hypertension (PH) had been reported in 11 infants being treated with diazoxide and that the PH resolved with withdrawal of diazoxide. All three of the cases in our hospital were admitted to the neonatal intensive care unit (NICU) for hypoglycemia. All patients received thorough radiologic and laboratory evaluations related to their diagnosis of CHI. All initially improved when diazoxide was initiated. Case 1 and case 3 were discharged from the NICU on diazoxide and chlorothiazide. Case 2 developed pulmonary hypertension while still in the NICU days after an increase in diazoxide dosing. Case 1 presented to the emergency room in respiratory distress shortly after discharge from the NICU with evidence of PH and heart failure. Case 3 presented to the emergency room after 2 weeks at home due to a home blood glucose reading that was low and developed PH and heart failure while an inpatient. Discontinuation of diazoxide led to resolution of all three patients' PH within approximately one week. The experience of our hospital indicates that pulmonary hypertension may be more common than previously thought in infants taking diazoxide. It is unclear if these symptoms develop slowly over time or if there is some other, as yet undescribed, trigger for the pulmonary hypertension. Our hospital's experience adds to the body of evidence and suggests these infants may benefit from more surveillance with echocardiography.

Blur, eye movements and performance on a driving visual recognition slide test.

PURPOSE: Optical blur and ageing are known to affect driving performance but their effects on drivers' eye movements are poorly understood. This study examined the effects of optical blur and age on eye movement patterns and performance on the DriveSafe slide recognition test which is purported to predict fitness to drive. METHODS: Twenty young (27.1 ± 4.6 years) and 20 older (73.3 ± 5.7 years) visually normal drivers performed the DriveSafe under two visual conditions: best-corrected vision and with +2.00 DS blur. The DriveSafe is a Visual Recognition Slide Test that consists of brief presentations of static, real-world driving scenes containing different road users (pedestrians, bicycles and vehicles). Participants reported the types, relative positions and direction of travel of the road users in each image; the score was the number of correctly reported items (maximum score of 128). Eye movements were recorded while participants performed the DriveSafe test using a Tobii TX300 eye tracking system. RESULTS: There was a significant main effect of blur on DriveSafe scores (best-corrected: 114.9 vs blur: 93.2; p < 0.001). There was also a significant age and blur interaction on the DriveSafe scores (p < 0.001) such that the young drivers were more negatively affected by blur than the older drivers (reductions of 22% and 13% respectively; p < 0.001): with best-corrected vision, the young drivers performed better than the older drivers (DriveSafe scores: 118.4 vs 111.5; p = 0.001), while with blur, the young drivers performed worse than the older drivers (88.6 vs 95.9; p = 0.009). For the eye movement patterns, blur significantly reduced the number of fixations on road users (best-corrected: 5.1 vs blur: 4.5; p < 0.001), fixation duration on road users (2.0 s vs 1.8 s; p < 0.001) and saccade amplitudes (7.4° vs 6.7°; p < 0.001). A main effect of age on eye movements was also found where older drivers made smaller saccades than the young drivers (6.7° vs 7.4°; p < 0.001). CONCLUSIONS: Blur reduced DriveSafe scores for both age groups and this effect was greater for the young drivers. The decrease in number of fixations and fixation duration on road users, as well as the reduction in saccade amplitudes under the blurred condition, highlight the difficulty experienced in performing the task in the presence of optical blur, which suggests that uncorrected refractive errors may have a detrimental impact on aspects of driving performance.

The association between race and age of diagnosis of retinoblastoma in United States children.

PURPOSE: To explore the associations between race and retinoblastoma diagnosis in United States children. METHODS: In this analytical nonconcurrent cohort study, we used 1988-2018 data from the Surveillance, Epidemiology, and End-Results (SEER) database. Children ages 0-17 with retinoblastoma were included (n = 758); those with missing data were excluded (n = 11; final cohort: n = 747). The exposure variable was race (White, Black, Asian/Pacific Islanders, American Indian/Alaska Native), and the outcome variable was diagnosis of retinoblastoma before versus after 2 years of age. Covariates included sex, rural-urban continuum, ethnicity, decade of diagnosis, and laterality of disease. Unadjusted and adjusted logistic regression analyses were performed to calculate odds ratios and 95% confidence intervals. RESULTS: No statistically significant association was found between racial/ethnic groups (OR = 0.61-0.99; P = 0.92) and age at diagnosis (OR = 0.86; P = 0.66). Females were more likely to be diagnosed earlier than males (OR = 0.62; 95% CI, 0.44-0.88; P = 0.042). No association was found between urban versus rural subjects (OR = 1.02; 95% CI, 0.60-1.75) or between decades (OR = 0.81; 95% CI, 0.54-1.22 and OR 0.96; 95% CI, 0.62-1.47). CONCLUSIONS: We found no statistically significant difference between racial/ethnic groups for diagnosis of children with retinoblastoma after 2 years of age. Future studies could explore why females are more likely than males to be diagnosed before 2 years of age.

Improved determination of protein turnover rate with heavy water labeling by mass isotopomer ratio selection.

The synthesis and degradation rates of proteins form an essential component of gene expression control. Heavy water labeling has been used in conjunction with mass spectrometry to measure protein turnover rates, but the optimal analytical approaches to derive turnover rates from the isotopomer patterns of deuterium labeled peptides continue to be a subject of research. Here we describe a method, which comprises a reverse lookup of numerically approximated peptide isotope envelopes, coupled to the selection of optimal isotopomer pairs based on peptide sequence, to calculate the molar fraction of new peptide synthesis in heavy water labeling mass spectrometry experiments. We validated this approach using an experimental calibration curve comprising mixtures of fully unlabeled and fully labeled proteomes. We then re-analyzed 17 proteome-wide turnover experiments from four mouse organs, and showed that the method increases the coverage of well-fitted peptides in protein turnover experiments by 25-82%. The method is implemented in the Riana software tool for protein turnover analysis, and may avail ongoing efforts to study the synthesis and degradation kinetics of proteins in animals on a proteome-wide scale. What's new: We describe a reverse lookup method to calculate the molar fraction of new synthesis from numerically approximated peptide isotopomer profiles in heavy water labeling mass spectrometry experiments. Using an experimental calibration curve comprising mixtures of fully unlabeled and fully labeled proteomes at various proportions, we show that this method provides a straightforward way to calculate the proportion of new proteins in a protein pool from arbitrarily chosen isotopomer ratios. We next analyzed which of the isotopomer pairs within the peptide isotope envelope yielded isotopomer time courses that fit most closely to kinetic models, and found that the identity of the isotopomer pair depends partially on the number of deuterium accessible labeling sites of the peptide. We next derived a strategy to automatically select the isotopomer pairs to calculate turnover rates based on peptide sequence, and showed that this increases the coverage of existing proteome-wide turnover experiments in multiple data sets of the mouse heart, liver, kidney, and skeletal muscle by up to 25-82%.

Tissue Usage Preference and Intrinsically Disordered Region Remodeling of Alternative Splicing Derived Proteoforms in the Heart.

A computational analysis of mass spectrometry data was performed to uncover alternative splicing derived protein variants across chambers of the human heart. Evidence for 216 non-canonical isoforms was apparent in the atrium and the ventricle, including 52 isoforms not documented on SwissProt and recovered using an RNA sequencing derived database. Among non-canonical isoforms, 29 show signs of regulation based on statistically significant preferences in tissue usage, including a ventricular enriched protein isoform of tensin-1 (TNS1) and an atrium-enriched PDZ and LIM Domain 3 (PDLIM3) isoform 2 (PDLIM3-2/ALP-H). Examined variant regions that differ between alternative and canonical isoforms are highly enriched in intrinsically disordered regions, and over two-thirds of such regions are predicted to function in protein binding and/or RNA binding. The analysis here lends further credence to the notion that alternative splicing diversifies the proteome by rewiring intrinsically disordered regions, which are increasingly recognized to play important roles in the generation of biological function from protein sequences.

Pravastatin reduces Marfan aortic dilation.

BACKGROUND: The sequelae of aortic root dilation are the lethal consequences of Marfan syndrome. The root dilation is attributable to an imbalance between deposition of matrix elements and metalloproteinases in the aortic medial layer as a result of excessive transforming growth factor-beta signaling. This study examined the efficacy and mechanism of statins in attenuating aortic root dilation in Marfan syndrome and compared effects to the other main proposed preventative agent, losartan. METHODS AND RESULTS: Marfan mice heterozygous for a mutant allele encoding a cysteine substitution in fibrillin-1 (C1039G) were treated daily from 6 weeks old with pravastatin 0.5 g/L or losartan 0.6 g/L. The end points of aortic root diameter (n=25), aortic thickness, and architecture (n=10), elastin volume (n=5), dp/dtmax (maximal rate of change of pressure) (cardiac catheter; n=20), and ultrastructural analysis with stereology (electron microscopy; n=5) were examined. The aortic root diameters of untreated Marfan mice were significantly increased in comparison to normal mice (0.161 ± 0.001 cm vs 0.252 ± 0.004 cm; P<0.01). Pravastatin (0.22 ± 0.003 cm; P<0.01) and losartan (0.221 ± 0.004 cm; P<0.01) produced a significant reduction in aortic root dilation. Both drugs also preserved elastin volume within the medial layer (pravastatin 0.23 ± 0.02 and losartan 0.29 ± 0.03 vs untreated Marfan 0.19 ± 0.02; P=0.01; normal mice 0.27 ± 0.02). Ultrastructural analysis showed a reduction of rough endoplasmic reticulum in smooth muscle cells with pravastatin (0.022 ± 0.004) and losartan (0.013 ± 0.001) compared to untreated Marfan mice (0.035 ± 0.004; P<0.01). CONCLUSIONS: Statins are similar to losartan in attenuating aortic root dilation in a mouse model of Marfan syndrome. They appear to act through reducing the excessive protein manufacture by vascular smooth muscle cells, which occurs in the Marfan aorta. As a drug that is relatively well-tolerated for long-term use, it may be useful clinically.

Development of the venom ducts in the centipede Scolopendra: an example of recapitulation.

In contrast to previous claims that (a) there is a law of recapitulation and, conversely, (b) recapitulation never happens, the evolutionary repatterning of development can take many forms, of which recapitulation is one. Here, we add another example to the list of case studies of recapitulation. This example involves the development of the venom claws (forcipules) in the centipede Scolopendra subspinipes mutilans, and in particular the development of the duct through which venom flows from the gland that produces it (proximal) to the opening called the meatus (distal) through which it is injected into prey. Most of the information we present is from early postembryonic stages--these have been neglected in previous work on centipede development. We show that the venom ducts arise from sutures that are invaginations of the cuticle. In S. s. mutilans, the invagination in each forcipule forms into a tubular structure that detaches itself from the exoskeleton and moves toward the center of the forcipule. This is in contrast to extant Scutigera, and also, probably, Scolopendra's extinct Scutigera-like ancestors, where the duct remains attached to the cuticle of throughout development. Thus, S. s. mutilans exhibits a recapitulatory repatterning of development.

Acute intrathoracic intestinal strangulation diagnosed by transthoracic echocardiography.

Transthoracic echocardiography plays a central role in diagnosing a variety of cardiac and pericardial disorders. However its use in identifying extra-cardiac thoracic pathology is less well recognised. We describe an unusual case of intrathoracic intestinal strangulation detected by transthoracic echocardiography. The recognition of bowel loops within the left hemithorax enabled rapid confirmatory computed tomographic imaging and subsequent life-saving surgery. This case demonstrates the utility of bedside echocardiography in the assessment of intrathoracic pathology and emphasises the need for cardiologists to be familiar with the echocardiographic appearance of these disorders.

An on-road examination of daytime and evening driving on rural roads: physiological, subjective, eye gaze, and driving performance outcomes.

Experiencing sleepiness when driving is associated with increased crash risk. An increasing number of studies have examined on-road driver sleepiness; however, these studies typically assess the effect of sleepiness during the late night or early morning hours when sleep pressure is approaching its greatest. An on-road driving study was performed to assess how a range of physiological and sleepiness measures are impacted when driving during the daytime and evening when moderate sleepiness is experienced. In total, 27 participants (14 women and 13 men) completed a driving session in a rural town lasting approximately 60 minutes, while physiological sleepiness (heart rate variability), subjective sleepiness, eye tracking data, vehicle kinematic data and GPS speed data were recorded. Daytime driving sessions began at 12:00 or 14:00, with the evening sessions beginning at 19:30 or 20:30; only a subset of participants (n = 11) completing the evening sessions (daytime and evening order counterbalanced). The results suggest reductions in the horizontal and vertical scanning ranges occurred during the initial 40 minutes of driving for both daytime and evening sessions, but with evening sessions reductions in scanning ranges occurred across the entire driving session. Moreover, during evening driving there was an increase in physiological and subjective sleepiness levels. The results demonstrate meaningful increases in sleepiness and reductions in eye scanning when driving during both the daytime and particularly in the evening. Thus, drivers need to remain vigilant when driving during the daytime and the evening.

Aerobic exercise reverses arterial inflammation with aging in mice.

We tested the hypothesis that regular aerobic exercise reverses arterial inflammation with aging. When compared with young controls (6.2 ± 0.4 mo; n = 7), old (31.3 ± 0.5 mo; n = 11) male B6D2F1 cage-restricted mice demonstrated increased arterial activation of the proinflammatory transcription factor NF-κB, as indicated by greater aortic phosphorylation of both the inhibitor of NF-κB kinase (IKK) and the p65 subunit of NF-κB (both P < 0.05). Similarly, aortic expression of the proinflammatory cytokines IL-1 and IL-6, IFN-γ, and TNF-α were greater in the old mice (all P < 0.05). Macrophage and T lymphocyte abundance was unchanged with age in the aortic intima and media but was markedly increased in the adventitia and perivascular fat tissue of old mice (all P < 0.05). This proinflammatory arterial phenotype with aging was associated with vascular dysfunction, as reflected by impaired nitric oxide-mediated endothelium-dependent dilation. Voluntary wheel running (10-14 wk) normalized aortic IKK-NF-κB activation, cytokine expression, adventitial and perivascular macrophage infiltration, and vascular function in old mice (32.4 ± 0.3 mo; n = 8) while having no consistent effects in young mice. Short-term voluntary wheel running started late in life reverses arterial inflammation with aging in mice possibly via outside-in actions. These anti-inflammatory effects may play an important role in the amelioration of age-associated vascular dysfunction by regular aerobic exercise.

Improving the safety of distracted pedestrians with in-ground flashing lights. A railway crossing field study.

INTRODUCTION: Current signage at intersections is designed for attentive pedestrians who are looking ahead. Such signage may not be sufficient when distracted by smartphones. Illuminated in-ground LED lights at crossings are an innovative solution to alert distracted pedestrians. METHOD: We conducted a field study at a railway crossing equipped with in-ground lights to assess whether distracted pedestrians (N = 34, Mean age 33.6 ±â€¯8.6 years) could detect these lights and how this impacted on their visual scanning and crossing behaviour. This involved a 2 × 3 repeated measures design exploring the impact of the presence (treatment) or absence (control) of in-ground lights (treatment) at a crossing, and a distractor task presented through a mobile device (none, visual, and audio) on eye movements recorded using an eye tracker, and verbal reporting of when participants detected the lights. RESULTS: Participants engaged in the distraction tasks as evidenced by their accuracy and reaction times in all conditions. With both the audio and visual distraction tasks, participants looked at the in-ground LEDs and detected their activation as accurately as when not distracted (95%). While most participants detected the lights at their activation, visual distraction resulted in 10% of the detections occurring as participants entered the rail corridor, suggesting effectiveness in gaining pedestrians' attention. Further, participants were significantly less likely to check for trains when visually distracted (70%), a 10% reduction compared to the no or audio distractor conditions (80% and 78% respectively). The introduction of the in-ground lights resulted in appropriate scanning of the rail tracks (77% and 78% for the visual and auditory distractor tasks respectively) similar to that of non-distracted participants for the crossing without lights (80%). CONCLUSIONS: Our findings indicate that illuminated in-ground lights could be useful in attracting the attention of distracted pedestrians at railway level crossings, and possibly at other road intersections. Practical Applications: Illuminated in-ground lights can be installed at rail and road intersections with known pedestrian distraction as a countermeasure. Further research is necessary to understand their long-term effects.

Structural and cellular changes in canine myxomatous mitral valve disease: an image analysis study.

BACKGROUND AND AIM OF THE STUDY: Myxomatous mitral valve disease (MMVD) is the single most common cardiac disease of the dog, and bears close similarities to chronic degenerative mitral valve disease in humans. However, limited quantitative data are available on cellular and morphological changes in both species. The study aim was to use an image analysis system to examine various morphological changes associated with MMVD, and in particular to measure changes in cell numbers in overtly myxomatous areas of the distal portion of the valve. METHODS: Mitral valve complexes were collected from normal dogs and dogs with varying severity of myxomatous mitral valve disease (veterinary Whitney grades 1-4; a measure of disease severity and age-related disease progression in the dog). An image analysis technique (ImageJ; National Institutes of Health, USA) was used to measure valve leaflet length, thickness, connective tissue content and density, glycosaminoglycan (GAG) content, cell number and shape in normal and myxomatous areas of diseased valves. RESULTS: There was a change in the valve leaflet anterior/posterior length ratio in the diseased valves, suggestive of valve lengthening. Distinct and statistically significant (p < 0.01) changes occurred in the valve thickness ratio for both anterior and posterior leaflets as the disease progressed, and the posterior leaflet thickness ratios were consistently higher than for the anterior leaflets. There was a statistically significant decrease in cell numbers in overtly myxomatous areas of the distal portion of affected valves compared to similar locations in normal valves, but there was no difference between the different grades of disease. The majority of cells in both diseased and normal valves had a circularity score typical of a spindle (elongated) shape. Connective tissue derangement was clearly seen in the myxomatous areas, and this was associated with a significant reduction in connective tissue density. The reduction in connective tissue density was associated with advancing disease severity (age). There was an increase in GAG expression with disease severity, as shown by the level of Alcian blue staining, but this could not be quantified with ImageJ. CONCLUSION: Mitral valve myxomatous degeneration in the dog is associated with lengthening and thickening of valve leaflets, a loss of connective tissue, and a decrease in cell numbers in selected myxomatous areas, but no change in cell circularity. Some of these changes were age- (disease severity-) related.

Evaluation of innervation of the mitral valves and the effects of myxomatous degeneration in dogs.

OBJECTIVE: To map aspects of the innervation of the mitral valve complex and determine any association with the development or progression of myxomatous mitral valve disease (MMVD) in dogs. SAMPLE POPULATION: Septal mitral valve leaflets from 11 dogs aged 6 months to > 10 years. PROCEDURES: Expression of protein gene product 9.5 (general neuronal marker), tyrosine hydroxylase (adrenergic innervation marker), vasoactive intestinal peptide (parasympathetic innervation marker), and calcitonin gene-related peptide (sensory innervation marker) was assessed by use of a standard immunohistochemical technique. Innervation was assessed qualitatively and semiquantitatively. Differences between valvular zones and between groups were analyzed statistically. RESULTS: MMVD was present in leaflets of all dogs > or = 5 years of age. Innervation was confirmed in all leaflets but was markedly reduced in leaflets of dogs > 10 years of age. Innervation was most dense at the base of valves and mainly associated with the epimysial, perimysial, and endomysial layers of the muscle and blood vessels within the valve. Innervation was reduced within the middle zone of the valve and lacking at the free edge. Innervation was not identified at the tip of the leaflet, the free edge, or the chordae. Nerve fibers were mostly sympathetic, with the remainder being parasympathetic or sensory. Existence of MMVD did not alter the pattern or density of innervation. CONCLUSIONS AND CLINICAL RELEVANCE: Mitral valve leaflets in the study dogs were innervated, with most of the nerve fibers associated with the myocardium in the valve base. Development of MMVD appeared to precede the reduction of innervation associated with advancing age.

Subjective Verticality Is Disrupted by Astigmatic Visual Distortion in Older People.

Purpose: There is little research evidence to explain why older adults have more problems adapting to new spectacles incorporating astigmatic changes than younger adults. We tested the hypothesis that astigmatic lenses oriented obliquely would lead to errors in verticality perception that are greater for older than younger adults. Methods: Participants included 12 young (mean ± SD age 25.1 ± 5.0 years) and 12 older (70.2 ± 6.3 years) adults with normal vision. Verticality perception was assessed using a computer-based subjective visual vertical (SVV) task, under static and dynamic (in the presence of a moving peripheral distractor) conditions and when viewing targets through the near refractive correction (control condition), and two forms of astigmatic lenses oriented in the vertical, horizontal, and oblique meridians. Results: The older group demonstrated much greater dynamic SVV errors (e.g., 3.4° for the control condition) than the younger group (1.2°, P = 0.002), larger errors with vertical and horizontal astigmatic lenses (older group 4.1°and 5.2° for toric and magnifier lenses vs. younger group 1.2° and 1.4°, respectively, P < 0.001), and a larger influence of the oblique astigmatic lenses (older group 5.6° vs. younger group 2.1°, P<0.001). Conclusions: Astigmatic lenses produced little or no errors in SVV in young adults, but large static and dynamic SVV errors in older adults. This indicates a greater reliance on visual input with increased age for SVV, and helps explain why oblique astigmatic refractive corrections can cause dizziness in older patients and why they report greater difficulties adapting to new spectacles with astigmatic changes.

Pedestrians distracted by their smartphone: Are in-ground flashing lights catching their attention? A laboratory study.

Pedestrian distraction is a growing road safety concern worldwide. While there are currently no studies linking distraction and pedestrian crash risk, distraction has been shown to increase risky behaviours in pedestrians, for example, through reducing visual scanning before traversing an intersection. Illuminated in-ground Light Emitting Diodes (LEDs) embedded into pathways are an emerging solution to address the growing distraction problem associated with mobile use while walking. The current study sought to determine if such an intervention was effective in attracting the attention of distracted pedestrians. We conducted a controlled laboratory study (N = 24) to evaluate whether pedestrians detected the activation of flashing LEDs when distracted by a smartphone more accurately and efficiently when the lights were located on the floor compared to a control position on the wall. Eye gaze movements via an eye tracker and behavioural responses via response times assessed the detection of these flashing LEDs. Distracted participants were able to detect the activation of the floor and wall-mounted LEDs with accuracies above 90%. The visual and auditory distraction tasks increased reaction times by 143 and 124 ms, respectively. Even when distracted, performance improved with floor LEDs close to participants, with reaction time improvements by 43 and 159 ms for the LEDs 2 and 1 ms away from the participant respectively. The addition of floor LED lights resulted in a performance similar to the one observed for wall-mounted LEDs in the non-distracted condition. Moreover, participants did not necessarily need to fixate on the LEDs to detect their activation, thus were likely to have detected them using their peripheral vision. The findings suggest that LEDs embedded in pathways are likely to be effective at attracting the attention of distracted pedestrians. Further research needs to be conducted in the field to confirm these findings, and to evaluate the actual effects on behaviour under real-world conditions.