Eyelid eversion for visualisation of the upper eyelid lamellae: An anatomical cadaver study

Oculoplastics Paper SessionControversy persists in surgical eyelid anatomy despite the routine use of microanatomical examination in modern eyelid research. The aim of our study was to facilitate visualisation of upper eyelid anatomy by optimising the orientation of cadaveric specimens. We studied the anatomy of everted eyelids, providing an excellent histological view of the posterior approach to the eyelid commonly used in surgery. Non-traumatic separation of the eyelid lamellae provides a new view of the eyelid's lamellar nature. Further application of this model may enhance understanding of the multilayered aspect of the levator aponeurosis. The technique may improve intraoperative understanding of critical eyelid anatomy and promote safer and more effective eyelid surgery.published_or_final_versionThe 26th Asia Pacific Academy of Ophthalmology Congress (APAO 2011), Sydney, Australia, 20-24 March 2011. In British Journal of Ophthalmology, 2011, v. 95 n. 10, p. 1376-137

Glucocorticoids promote structural and functional maturation of foetal cardiomyocytes: a role for PGC-1α

Glucocorticoid levels rise dramatically in late gestation to mature foetal organs in readiness for postnatal life. Immature heart function may compromise survival. Cardiomyocyte glucocorticoid receptor (GR) is required for the structural and functional maturation of the foetal heart in vivo, yet the molecular mechanisms are largely unknown. Here we asked if GR activation in foetal cardiomyocytes in vitro elicits similar maturational changes. We show that physiologically relevant glucocorticoid levels improve contractility of primary-mouse-foetal cardiomyocytes, promote Z-disc assembly and the appearance of mature myofibrils, and increase mitochondrial activity. Genes induced in vitro mimic those induced in vivo and include PGC-1α, a critical regulator of cardiac mitochondrial capacity. SiRNA-mediated abrogation of the glucocorticoid induction of PGC-1α in vitro abolished the effect of glucocorticoid on myofibril structure and mitochondrial oxygen consumption. Using RNA sequencing we identified a number of transcriptional regulators, including PGC-1α, induced as primary targets of GR in foetal cardiomyocytes. These data demonstrate that PGC-1α is a key mediator of glucocorticoid-induced maturation of foetal cardiomyocyte structure and identify other candidate transcriptional regulators that may play critical roles in the transition of the foetal to neonatal heart

Membrane vesicles, current state-of-the-art: emerging role of extracellular vesicles

Release of membrane vesicles, a process conserved in both prokaryotes and eukaryotes, represents an evolutionary link, and suggests essential functions of a dynamic extracellular vesicular compartment (including exosomes, microparticles or microvesicles and apoptotic bodies). Compelling evidence supports the significance of this compartment in a broad range of physiological and pathological processes. However, classification of membrane vesicles, protocols of their isolation and detection, molecular details of vesicular release, clearance and biological functions are still under intense investigation. Here, we give a comprehensive overview of extracellular vesicles. After discussing the technical pitfalls and potential artifacts of the rapidly emerging field, we compare results from meta-analyses of published proteomic studies on membrane vesicles. We also summarize clinical implications of membrane vesicles. Lessons from this compartment challenge current paradigms concerning the mechanisms of intercellular communication and immune regulation. Furthermore, its clinical implementation may open new perspectives in translational medicine both in diagnostics and therapy

Lawson criterion for ignition exceeded in an inertial fusion experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion

Multipositional High-Resolution Magnetic Resonance Imaging of the Human Orbit Functional Anatomy

info:eu-repo/semantics/publishe

Surgical microanatomy of the Müller muscle-conjunctival resection ptosis procedure

Purpose: To assess for alterations in the microscopic anatomy that occur as a result of the Müller muscle-conjunctival resection (MMCR) ptosis procedure and to better understand the mechanisms by which MMCR elevates the eyelid. Methods: Sixteen orbits from 8 fresh frozen Caucasian cadaver heads, ranging from 38 to 100 years of age were used. For each head, MMCR was performed on one side. The contralateral, unoperated orbit served as an anatomic control. Each exenterated orbital contents and excised MMCR specimen was evaluated. The histopathology of the eyelids and MMCR specimens were studied microscopically by staining with hematoxylin-eosin, elastic, and Verhoeff-Masson trichrome. Results: Müller muscle and conjunctiva were present in all 8 of the excised MMCR specimens. Elastic fibers consistent with Müller muscle tendon or among the smooth muscle fibers were seen within all excised MMCR specimens. The levator aponeurosis was intact in 8 of 8 operated eyelids; however, the aponeurosis was plicated in all. The accessory lacrimal gland tissues were intact in all of the operated and unoperated eyelids. Conclusions: MMCR works by shortening the posterior lamella, which results in advancement of the levator palpebrae superioris muscle and plication of the levator aponeurosis. Plication of the levator aponeurosis likely contributes to the increased volumetric effect seen clinically after MMCR. Phenylephrine testing can help in fine-tuning the amount of resection, but given the mechanism of action of MMCR, adequate levator muscle function remains a critical factor in the success of the surgery. Moreover, MMCR preserves accessory lacrimal gland tissues. © 2010 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc.link_to_subscribed_fulltex