Intersubject Regularity in the Intrinsic Shape of Human V1

Previous studies have reported considerable intersubject variability in the three-dimensional geometry of the human primary visual cortex (V1). Here we demonstrate that much of this variability is due to extrinsic geometric features of the cortical folds, and that the intrinsic shape of V1 is similar across individuals. V1 was imaged in ten ex vivo human hemispheres using high-resolution (200 μm) structural magnetic resonance imaging at high field strength (7 T). Manual tracings of the stria of Gennari were used to construct a surface representation, which was computationally flattened into the plane with minimal metric distortion. The instrinsic shape of V1 was determined from the boundary of the planar representation of the stria. An ellipse provided a simple parametric shape model that was a good approximation to the boundary of flattened V1. The aspect ration of the best-fitting ellipse was found to be consistent across subject, with a mean of 1.85 and standard deviation of 0.12. Optimal rigid alignment of size-normalized V1 produced greater overlap than that achieved by previous studies using different registration methods. A shape analysis of published macaque data indicated that the intrinsic shape of macaque V1 is also stereotyped, and similar to the human V1 shape. Previoud measurements of the functional boundary of V1 in human and macaque are in close agreement with these results

Analysis of best corrected visual acuity following corneal refractive surgery comparing low and standard predicted postoperative keratometry

BACKGROUND: It is a commonly held view in the ophthalmologic community that eyes with sufficiently low calculated postoperative corneal keratometry, less than 35 diopters, should not undergo corrective refractive laser surgery (CRLS) due to the increased risk of best corrected visual acuity (BCVA) loss. Typical CRLS include Laser In-Situ Keratomileusis (LASIK), Photorefractive Keratectomy (PRK), and Laser-Assisted Sub-Epithelial Keratectomy (LASEK). Evidence for this claim in currently available literature is sparse and inconsistent. PURPOSE: To further elucidate the relationship between calculated “flat” postoperative corneal keratometry and loss of BCVA. Additionally, to investigate the role of procedure type (LASIK, ASA, or LASEK) and degree of calculated postoperative corneal flatness on visual outcomes following CRLS. METHODS: 222 eyes (111 candidates and 111 controls) were retrospectively analyzed and matched based on calculated postoperative keratometry compared to control subgroups with calculated postoperative keratometries ≥38 D and further stratified into subgroups 1b (K=38-38.99 D), 2b (K=39-39.99 D), 3b (K=40-40.9 9D), and 4b (K≥41 D). All of the eyes had undergone LASIK, PRK, or LASEK between December 2008 and November 2016 at Boston Eye Group/Boston Laser in Brookline, MA. RESULTS: Statistical analyses showed no significant differences between candidates and controls in preoperative BCVA (p=0.650) and postoperative BCVA (p=0.081). Subgroup matching showed no significant differences in the amount of tissue ablated in 1a & 1b (p=0.946), 2a & 2b (p=0.694), 3a & 3b (p=0.989), and 4a & 4b (p=0.986). There was also no significant change between preoperative and postoperative BCVA in subgroups 1a (p=0.367), 2a (p=0.297), 3a (p=0.576), 4a (p=0.669), 1b (p=0.458), 2b (p=0.227), 3b (p=0.071), or 4b (p=0.703). 3 of 111 (2.70%) candidate eyes and 1 (0.90%) control eye lost 1+ lines of BCVA following surgery. There was no statistical difference in 1+ lines of BCVA lost between these groups (p=0.313). Similarly, the type of CRLS undergone did not affect the rate of BCVA line loss (p=0.793). CONCLUSION: Our evidence suggests that in a matched comparison of flat and normal mathematically predicted postoperative keratometries, there was no increase in BCVA lost due to flat keratometry

Interaction of cultured human endothelial cells with polymeric surfaces of different wettabilities

The in vitro interaction of human endothelial cells (HEC) and polymers with different wettabilities in culture medium containing serum was investigated. Optimal adhesion of HEC generally occurred onto moderately wettable polymers. Within a series of cellulose type of polymers the cell adhesion increased with increasing contact angle of the polymer surfaces. Proliferation of HEC occurred when adhesion was followed by progressive flattening of the cells.\ud \ud Our results suggest that moderately wettable polymers exhibit a serum and/or cellular protein adsorption pattern that is favourable for growth of HEC

Cardiac electrical defects in progeroid mice and Hutchinson-Gilford progeria syndrome patients with nuclear lamina alterations

Hutchinson–Gilford progeria syndrome (HGPS) is a rare genetic disease caused by defective prelamin A processing, leading to nuclear lamina alterations, severe cardiovascular pathology, and premature death. Prelamin A alterations also occur in physiological aging. It remains unknown how defective prelamin A processing affects the cardiac rhythm. We show age-dependent cardiac repolarization abnormalities in HGPS patients that are also present in the Zmpste24-/- mouse model of HGPS. Challenge of Zmpste24-/- mice with the ß-adrenergic agonist isoproterenol did not trigger ventricular arrhythmia but caused bradycardia-related premature ventricular complexes and slow-rate polymorphic ventricular rhythms during recovery. Patch-clamping in Zmpste24-/- cardiomyocytes revealed prolonged calcium-transient duration and reduced sarcoplasmic reticulum calcium loading and release, consistent with the absence of isoproterenol-induced ventricular arrhythmia. Zmpste24-/- progeroid mice also developed severe fibrosis-unrelated bradycardia and PQ interval and QRS complex prolongation. These conduction defects were accompanied by overt mislocalization of the gap junction protein connexin43 (Cx43). Remarkably, Cx43 mislocalization was also evident in autopsied left ventricle tissue from HGPS patients, suggesting intercellular connectivity alterations at late stages of the disease. The similarities between HGPS patients and progeroid mice reported here strongly suggest that defective cardiac repolarization and cardiomyocyte connectivity are important abnormalities in the HGPS pathogenesis that increase the risk of arrhythmia and premature death.Peer ReviewedPostprint (published version

Power and politics in research design and practice: Opening up space for social equity in interdisciplinary, multi-jurisdictional and community-based research

Working collaboratively with communities is commonly considered a cornerstone of good practice in research involving social-ecological concerns. Increasingly, funding agencies also recognise that such collaborations are most productive when community partners have some influence on the design and implementation of the projects that benefit from their participation. However, researchers engaged with this work often struggle to actively engage community members in this way and, in particular, Indigenous peoples. In this article, we argue that useful strategies for facilitating such engagement are to leave space in the research plan for questions of interest to community partners and to encourage equitable interactions between all participants through the use of forums in which power dynamics are intentionally flattened. We demonstrate the use of this technique in an interdisciplinary, multi-jurisdictional research study involving the fate and transport of toxic compounds that lead to fish consumption advisories throughout the world. In this project, the use of participatory forums resulted in community partners in Michigan’s Keweenaw Bay area of Lake Superior shaping a key aspect of the research by raising the simple but significant question: ‘When can we eat the fish?’. Their interest in this question also helped to ensure that they would remain meaningful partners throughout the duration of the project. The conclusion emphasises that further integration of Indigenous and community-based research methods has the potential to significantly enhance the process and value of university-community research engagement in the future

Clinical Utility of Echocardiography in Former Preterm Infants with Bronchopulmonary Dysplasia.

BackgroundThe clinical utility of echocardiography for the diagnosis of pulmonary vascular disease (PVD) in former preterm infants with bronchopulmonary dysplasia (BPD) is not established. Elevated pulmonary vascular resistance (PVR) rather than pulmonary artery pressure (PAP) is the hallmark of PVD. We evaluated the utility of echocardiography in infants with BPD in diagnosing pulmonary hypertension and PVD (PVR >3 Wood units × m2) assessed by cardiac catheterization.MethodsA retrospective single center study of 29 infants born ≤29 weeks of gestational age with BPD who underwent cardiac catheterization and echocardiography was performed. PVD was considered present by echocardiography if the tricuspid valve regurgitation jet peak velocity was >2.9 m/sec, post-tricuspid valve shunt systolic flow velocity estimated a right ventricular systolic pressure >35 mm Hg, or systolic septal flattening was present. The utility (accuracy, sensitivity, and positive predictive value [PPV]) of echocardiography in the diagnosis of PVD was tested. Subgroup analysis in patients without post-tricuspid valve shunts was performed. Echocardiographic estimations of right ventricular pressure, dimensions, function, and pulmonary flow measurements were evaluated for correlation with PVR.ResultsThe duration between echocardiography and cardiac catheterization was a median of 1 day (interquartile range, 1-4 days). Accuracy, sensitivity, and PPV of echocardiography in diagnosing PVD were 72%, 90.5%, and 76%, respectively. Accuracy, sensitivity, and PPV increased to 93%, 91.7%, and 100%, respectively, when infants with post-tricuspid valve shunts were excluded. Echocardiography had poor accuracy in estimating the degree of PAP elevation by cardiac catheterization. In infants without post-tricuspid valve shunts, there was moderate to good correlation between indexed PVR and right ventricular myocardial performance index (rho = 0.89, P = .005), systolic to diastolic time index (0.84, P < .001), right to left ventricular diameter ratio at end systole (0.66, P = .003), and pulmonary artery acceleration time (0.48, P = .05).ConclusionsEchocardiography performs well in screening for PVD in infants with BPD and may be diagnostic in the absence of a post-tricuspid valve shunt. However, cardiac catheterization is needed to assess the degree of PAP elevation and PVR. The diagnostic utility of echocardiographic measurements that correlate with PVR should be evaluated prospectively in this patient population