Epigenetics and cell death: DNA hypermethylation in programmed retinal cell death.

BackgroundVertebrate genomes undergo epigenetic reprogramming during development and disease. Emerging evidence suggests that DNA methylation plays a key role in cell fate determination in the retina. Despite extensive studies of the programmed cell death that occurs during retinal development and degeneration, little is known about how DNA methylation might regulate neuronal cell death in the retina.MethodsThe developing chicken retina and the rd1 and rhodopsin-GFP mouse models of retinal degeneration were used to investigate programmed cell death during retinal development and degeneration. Changes in DNA methylation were determined by immunohistochemistry using antibodies against 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC).ResultsPunctate patterns of hypermethylation paralleled patterns of caspase3-dependent apoptotic cell death previously reported to occur during development in the chicken retina. Degenerating rd1 mouse retinas, at time points corresponding to the peak of rod cell death, showed elevated signals for 5mC and 5hmC in photoreceptors throughout the retina, with the most intense staining observed in the peripheral retina. Hypermethylation of photoreceptors in rd1 mice was associated with TUNEL and PAR staining and appeared to be cCaspase3-independent. After peak rod degeneration, during the period of cone death, occasional hypermethylation was observed in the outer nuclear layer.ConclusionThe finding that cell-specific increases of 5mC and 5hmC immunostaining are associated with the death of retinal neurons during both development and degeneration suggests that changes in DNA methylation may play a role in modulating gene expression during the process of retinal degeneration. During retinal development, hypermethylation of retinal neurons associates with classical caspase-dependent apoptosis as well as caspase-3 independent cell death, while hypermethylation in the rd1 mouse photoreceptors is primarily associated with caspase-3 independent programmed cell death. These findings suggest a previously unrecognized role for epigenetic mechanisms in the onset and/or progression of programed cell death in the retina

A case of atypical insertion of the levator scapulae

Anatomical variations in the musculature of the spine have the potential to cause functional and postural abnormalities, which in turn could lead to chronic myofascial and skeletal pain. We present a unilateral case of a 71-year-old Caucasian female in which the left levator scapulae muscle gave rise to an accessory head that inserted, by way of a flat aponeurotic band, to the ligamentum nuchae, the tendon of the rhomboideus major and the superior aspect of the serratus posterior superior muscle. The innervation was provided by a branch of the dorsal scapular nerve. By exerting unilateral traction on the vertebrae and surrounding musculature, this unusual variation might have resulted in clinical consequences including scoliosis and movement abnormalities of the head and neck as well as myofascial pain syndrome

A retrotracheal right subclavian artery in association with a vertebral artery and thyroidea ima

The retro-oesophageal right subclavian artery is an anatomical abnormality encountered by anatomists and pathologists and, more recently, interventional cardiologists and thoracic surgeons with an incidence of 0.2-2% in the population. We report a case of a retrotracheal right subclavian artery which originated distally along the left aortic arch and coursed between the trachea and the oesophagus. Additionally, the aortic arch gave rise to a common trunk, which subsequently bifurcated to yield to a right vertebral artery and a left thyroidea ima, replacing the left inferior thyroid artery. Consequently the right and the left recurrent laryngeal nerves were found to recur normally. The possible embryonic development of these branching patterns and their clinical significance is discussed

Definitions and standardization of a new grading scheme for eyelid contour abnormalities after trichiasis surgery

Background: Clear definitions of outcomes following trichiasis surgery are critical for planning program evaluations and for identifying ways to improve trichiasis surgery. Eyelid contour abnormality is an important adverse outcome of surgery; however, no standard method has been described to categorize eyelid contour abnormalities. Methodology/Principal Findings: A classification system for eyelid contour abnormalities following surgery for trachomatous trichiasis was developed. To determine whether the grading was reproducible using the classification system, six-week postoperative photographs were reviewed by two senior graders to characterize severity of contour abnormalities. Sample photographs defining each contour abnormality category were compiled and used to train four new graders. All six graders independently graded a Standardization Set of 75 eyelids, which included a roughly equal distribution across the severity scale, and weighted kappa scores were calculated. Two hundred forty six-week postoperative photographs from an ongoing clinical trial were randomly selected for evaluating agreement across graders. Two months after initial grading, one grader regraded a subset of the 240 photographs to measure longer-term intra-observer agreement. The weighted kappa for agreement between the two senior graders was 0.80 (95% CI: 0.71-0.89). Among the Standardization Set, agreement between the senior graders and the 4 new graders showed weighted kappa scores ranging from 0.60-0.80. Among 240 eyes comprising the clinical trial dataset, agreement ranged from weighted kappa 0.70-0.71. Longer-term intra-observer agreement was weighted kappa 0.86 (95% CI: 0.80-0.92). Conclusions/Significance: The standard eyelid contour grading system we developed reproducibly delineates differing levels of contour abnormality. This grading system could be useful both for helping to evaluate trichiasis surgery outcomes in clinical trials and for evaluating trichiasis surgery programs

Relationship between immediate post-operative appearance and 6-week operative outcome in trichiasis surgery

Background: Surgical technique, including suture placement and tension, is believed to contribute to the outcome of bilamellar tarsal rotation surgery for trachomatous trichiasis. However, the immediate post-operative appearance that minimizes the chance of recurrence and other adverse outcomes has not been investigated. Methodology/Principal Findings: To explore whether the degree of correction immediately after surgery is predictive of surgical outcome at the 6-week post-operative visit, photographs taken immediately after surgery were used to predict surgical outcomes, including the severity of eyelid contour abnormality and trichiasis recurrence. Both eyelid contour abnormalities and recurrence were accurately predicted from the immediate post-operative photographs by an experienced oculoplastic surgeon 85% and 70% of the time, respectively. Participants with a "slight over-correction" that resulted in no eyelid contour abnormality and no recurrence were used to identify immediate post-operative contours that lead to a successful surgical outcome. Conclusions/Significance: The immediate post-operative eyelid contour is an important indicator of post-operative success of BLTR surgery. Based upon our findings, we developed a Surgery Photocard. This card illustrates some examples of immediate post-surgical appearances, which led to a successful outcome, as well as sub-optimal appearances, which led to poor surgical outcomes. The card also provides suggestions for improving the appearance by adjusting the suture placement or tension based upon standard oculoplastic principles

Evaluation and implementation of a mannequin-based surgical simulator for margin-involving eyelid laceration repair – a pilot study

Background: Repair of margin-involving eyelid lacerations is a challenge for beginning ophthalmology residents, yet no commercially-available simulation models exist for learning this skill. The objective of the study was to modify a mannequin-based surgical simulator originally developed for trachomatous trichiasis surgery training to teach margin-involving eyelid laceration repair and to evaluate its success within a residency wet-lab environment. Methods: We modified a previously developed mannequin-based training system for trachomatous trichiasis surgery into a simulator for margin-involving eyelid laceration repair. Six ophthalmology residents from a tertiary care academic institution performed at least one simulated margin-involving eyelid laceration repair using the surgical simulator between September 2019 and March 2020. Each session was video recorded. Two oculoplastic surgeons reviewed the videos in a blinded fashion to assess surgical proficiency using a standardized grading system. Participants were surveyed on their comfort level with eyelid laceration repair pre- and post-completion of simulation. They were also queried on their perceived usefulness of the surgical simulator compared to past methods and experiences. Results: Six residents completed 11 simulation surgeries. For three residents who completed more than one session, a slight increase in their skills assessment score and a decrease in operative time over two to three simulation sessions were found. Self-reported comfort level with margin-involving eyelid laceration repairs was significantly higher post-simulation compared to pre-simulation (p = 0.02). Residents ranked the usefulness of our surgical simulator higher than past methods such as fruit peels, surgical skill boards, gloves, and pig feet (p = 0.03) but lower than operating room experience (p = 0.02). Residents perceived the surgical simulator to be as useful as cadaver head and emergency department/consult experience. Conclusions: We developed a surgical simulator for teaching eyelid laceration repair and showed its utility in developing trainees’ surgical skills. Our surgical simulator was rated to be as useful as a cadaver head but is more readily available and cost effective

Estimating individual cone fundamentals from their color-matching functions

Estimation of individual spectral cone fundamentals from color-matching functions is a classical and longstanding problem in color science. In this paper we propose a novel method to carry out this estimation based on a linear optimization technique, employing an assumption of a priori knowledge of the retinal absorptance functions. The result is an estimation of the combined lenticular and macular filtration for an individual, along with the nine coefficients in the linear combination that relates their color-matching functions to their estimated spectral-cone fundamentals. We test the method on the individual Stiles and Burch color-matching functions and derive cone-fundamental estimations for different viewing fields and matching experiment repetition. We obtain cone-fundamental estimations that are remarkably similar to those available in the literature. This suggests that the method yields results that are close to the true fundamentals

A New Surgical Technique for Postoperative Trachomatous Trichiasis

INTRODUCTION: The World Health Organization has identified management of postoperative trichiasis (PTT) as one of the key remaining areas of focus needed to eliminate blinding trachoma as a public health problem. We developed the Bevel-Rotation Advancement Procedure (B-RAP) to treat individuals who need repeat trichiasis surgery. METHODS: Scarring caused by trichiasis surgery can cause the eyelid to become thick and distorted, making repeat surgery more difficult. To minimize eyelid thickness following B-RAP, a beveled incision of the tarsus is made allowing a marginal rotation of the eyelash fragment. Dissection between the anterior and posterior lamellae above the beveled incision and removal of scar tissue allows the marginal rotation to be combined with a posterior lamellar advancement to treat severely scarred eyelids with PTT and eyelid contour abnormalities (ECAs). RESULTS: Two surgeons performed B-RAP on 44 eyelids of 30 patients with PTT. The number of prior trachomatous trichiasis (TT) surgeries ranged from 2 to more than 4. At the 3-6 months postoperative visit, 37 eyelids (84%) had no recurrence of PTT. Three eyelids had central lashes touching; the remaining eyelids with recurrent PTT had nasal and temporal lashes touching. Fifteen eyelids (34%) had ECAs, but only 1 was severe. CONCLUSIONS: B-RAP was developed considering the altered eyelid anatomy found in the postsurgical eyelid with TT. Thinning of the eyelash fragment and removal of postoperative scar tissue improves the ability to advance and stabilize the eyelash fragment after external rotation. B-RAP shows promise as a procedure for improving outcomes of repeat trichiasis surgery

Definitions and Standardization of a New Grading Scheme for Eyelid Contour Abnormalities after Trichiasis Surgery

Approximately 8 million individuals worldwide suffer from trichiasis, a condition characterized by in-turned lashes that rub against the eye. Trichiasis is caused by repeated or prolonged ocular infection with Chlamydia trachomatis. Surgery is available to correct in-turned lashes. In most programmatic and research settings, the primary determinant of surgical success is whether or not lashes are touching the globe post-operatively. However, other surgical outcomes such as the contour of the eyelid are also important. Yet, no standard method for evaluating and reporting this outcome has been defined. In this study, we developed and tested a grading system for evaluating the severity of eyelid contour abnormalities after surgery using photographs of eyelids six weeks post-operatively. We found good agreement across photograph graders and also between field and photograph grades. This system should be useful in helping to standardize reporting of this outcome

Characteristics and perspectives of patients with postoperative trichiasis in Hadiya Zone, Ethiopia

Background: Postoperative trachomatous trichiasis (PTT) is a challenge for trichiasis surgery programs. Little is known about PTT patients' perceptions regarding outcomes and future disease management. This study aimed to understand the characteristics of PTT patients, how they managed trichiasis and their perceptions of prior surgeries and future surgery uptake. Methods: Patients with PTT were identified during an existing trichiasis screening program in Hadiya Zone, Ethiopia. A vision assessment and evaluation of the eyelids were conducted to determine distance vision, presence and severity of trichiasis and eyelid contour abnormalities. A questionnaire was administered to obtain information regarding patients' perceptions of surgery and PTT management approaches. Descriptive statistics were used to characterize PTT and determine associations between PTT severity and patient perceptions. Results: Among 404 participants, most were female (79.7%) and aged 40-60 y (62.6%). In total, 514 eyelids had PTT, and nearly half had severe PTT (46.9%). Although >50% of participants were currently epilating to manage their PTT, the majority (82.8%) indicated that they wanted repeat surgery. Most participants indicated that pain persisted despite epilation. The majority (75.1%) indicated satisfaction with their prior surgery and 59.6% indicated that they would recommend surgery to others. Conclusions: This study, which included a large proportion of severe PTT cases, indicated that individuals were generally satisfied with prior surgery and would prefer to have surgery again for PTT management