SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Vitreous humour

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PurposeTo evaluate the effects of intravitreal autologous plasmin enzyme (APE) in patients with focal vitreomacular traction (VMT).MethodsAPE was obtained by incubation of patient-derived purified plasminogen with streptokinase, and intravitreally injected 5-12 days later. Twenty-four hours after injection, in case of incomplete VMT release, a pars plana vitrectomy was performed. The hyaloid internal limiting membrane adherence and removal of the posterior hyaloid were intraoperatively evaluated.ResultsThirteen patients were recruited. During preparation of APE, five patients had spontaneous release of VMT. Eight patients received APE injection (2 IU). In five patients, spontaneous resolution of VMT occurred before APE administration. Twenty-four hours after injection, persistence of VMT was detected in all the eight treated patients. Best-corrected visual acuity was 0.51±0.37 LogMAR at baseline, improving to 0.23±0.14 LogMAR at 6 months (P=0.002). Foveal thickness was 464±180 μm at baseline, reducing to 246±59 μm at 6 months (P<0.001). Hyaloid was intraoperatively judged 'partially detached' in seven cases and 'totally detached' in one case. Hyaloid peeling was evaluated 'easy' in six eyes and 'very easy' in two eyes.ConclusionsIn the current study, there was a large percentage of spontaneous resolution of VMT before an APE administration. A single intravitreal APE injection seems insufficient to induce a complete posterior vitreous detachment in these patients.Eye advance online publication, 14 December 2012; doi:10.1038/eye.2012.248.

Concepts: Eye, Visual acuity, Ophthalmology, Vitrectomy, Retinal detachment, Vitreous humour, Epiretinal membrane, Posterior vitreous detachment

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PURPOSE: Review our experience in the use of indocyanine green (ICG) enhanced transpupillary thermotherapy (TTT) in combination with ophthalmic artery chemosurgery for retinoblastomas unresponsive to standard TTT. METHODS: Single centre, retrospective study of 16 eyes in 13 retinoblastoma patients treated with TTT and ICG via indirect ophthalmoscope: 23 treatments of 16 eyes, with a mean follow-up of 12.1 months (range 3-35 months). Outcome measures included tumour response and electroretinogram. RESULTS: Treatment resulted in significant tumour regression in all eyes: 13 eyes with well-differentiated characteristics, 2 with implanting vitreous seeds and 1 eye refractory to traditional TTT. ERG function was retained in all eyes. CONCLUSIONS: ICG-enhanced TTT with ophthalmic artery chemosurgery can effectively treat retinoblastoma refractory to conventional focal treatments without deleterious ocular side effects.

Concepts: Retina, Eye, Ophthalmology, Vitreous humour, Indocyanine green, Optic disc, Ophthalmic artery, Ophthalmoscope

27

Three patients had unilateral vitreomacular traction (VMT) syndrome and the diagnosis was confirmed by spectral domain-type optical coherence tomography (OCT). All patients were female aged 51, 55 and 62 years. All denied surgical intervention. In one patient, rapid spontaneous resolution of the vitreomacular traction with a complete posterior vitreous detachment (PVD) and a normal foveal contour was achieved within 15 days. In the remaining two cases a complete PVD could be detected as late as seven months after the initial presentation. In one, though the vitreomacular adhesion released spontaneously, there was a minimal residual epiretinal membrane. In all three eyes, visual acuity was considerably improved. Spontaneous, uneventful resolution has been rarely reported in the natural course of VMT but several recent studies with the aid of OCT have shown that spontaneous resolution might be more common than previously known. In light of our cases, we believe that there is still room to search for OCT clues in eyes with VMT to predict eyes with higher likelihood of spontaneous resolution, thereby avoiding unnecessary pharmacologic and/or surgical intervention.

Concepts: Optics, Retina, Eye, Visual acuity, Ophthalmology, Vitreous humour, Epiretinal membrane, Posterior vitreous detachment

26

It is widely accepted that the origin of subretinal fluid in rhegmatogenous retinal detachment (RRD) is liquid vitreous and that posterior vitreous detachment (PVD) and associated retinal tears are caused by vitreoretinal traction from intra-ocular currents, contraction of collagen fibers, and gravity. These explanations, however, are incomplete. We present a new synthesis of experimental and clinical evidence, updating understanding of fundamental pathophysiological processes in RRD. Misdirected aqueous flow is shown to more convincingly explain the origin of subretinal fluid in clinical RRD, to be the most likely cause of acute PVD and retinal tear formation, and also to contribute to initial detachment of the retina at retinal tears. Misdirected aqueous flow in RRD is a pathophysiological process, rather than the “aqueous misdirection syndrome”, and occurs without visible anterior chamber shallowing or acute glaucoma.

Concepts: Retina, Glaucoma, Ophthalmology, Retinal detachment, Myopia, Vitreous humour, Posterior vitreous detachment, Lattice degeneration

25

Detection and quantification of drugs from various biological matrices are of immense importance in forensic toxicological analysis. Despite the various reported methods, development of a new method for the detection and quantification of drugs is still an active area of research. However, every method and biological matrix has its own limitation, which further encourage forensic toxicologists to develop new methods and to explore new matrices for the analysis of drugs. In this study, an electrospray ionization-liquid chromatograph-tandem mass spectrometry (ESI-LC-MS/MS) method is developed and validated for simultaneous identification and quantification of 24 drugs of forensic relevance in various body fluids, namely, whole blood, plasma and vitreous humour. The newly developed method has been validated for intra-day and inter-day accuracy, precision, selectivity and sensitivity. Absolute recovery shows a mean of 84.5, 86.2, and 103% in the vitreous humour, whole blood and plasma respectively, which is suitable for the screening procedure. Further, the absolute matrix effect (AME) shows a mean of 105, 96.5, and 109% in the vitreous humour, whole blood and plasma, respectively. In addition, to examine the practical utility of this method, it has been applied for screening of drugs in post-mortem samples of the vitreous humour, whole blood and plasma collected at autopsy from ten cadavers. Experimental results show that the newly developed method is well applicable for screening of analytes in all the three matrices. Copyright © 2015 John Wiley & Sons, Ltd.

Concepts: Blood, New York City, Blood donation, Embalming, Vitreous humour, Forensic toxicology, Human Development Index, Body fluids

14

The receptor-associated prorenin system (RAPS) refers to the pathogenic mechanism whereby prorenin binding to the (pro)renin receptor [(P)RR] dually activates the tissue renin-angiotensin system (RAS) and RAS-independent intracellular signaling. Here we revealed significant upregulation of prorenin and soluble (P)RR levels in the vitreous fluid of patients with uveitis compared to non-inflammatory controls, together with a positive correlation between these RAPS components and monocyte chemotactic protein-1 among several upregulated cytokines. Moreover, we developed a novel single-strand RNAi agent, proline-modified short hairpin RNA directed against human and mouse (P)RR [(P)RR-PshRNA], and we determined its safety and efficacy in vitro and in vivo. Application of (P)RR-PshRNA in mice caused significant amelioration of acute (uveitic) and chronic (diabetic) models of ocular inflammation with no apparent adverse effects. Our findings demonstrate the significant implication of RAPS in the pathogenesis of human uveitis and the potential usefulness of (P)RR-PshRNA as a therapeutic agent to reduce ocular inflammation.

Concepts: Immune system, DNA, Bacteria, Signal transduction, RNA, Cell biology, Chemokine, Vitreous humour

4

To develop a disease activity index for patients with uveitis (UVEDAI) encompassing the relevant domains of disease activity considered important among experts in this field. The steps for designing UVEDAI were: (a) Defining the construct and establishing the domains through a formal judgment of experts, (b) A two-round Delphi study with a panel of 15 experts to determine the relevant items, © Selection of items: A logistic regression model was developed that set ocular inflammatory activity as the dependent variable. The construct “uveitis inflammatory activity” was defined as any intraocular inflammation that included external structures (cornea) in addition to uvea. Seven domains and 15 items were identified: best-corrected visual acuity, inflammation of the anterior chamber (anterior chamber cells, hypopyon, the presence of fibrin, active posterior keratic precipitates and iris nodules), intraocular pressure, inflammation of the vitreous cavity (vitreous haze, snowballs and snowbanks), central macular edema, inflammation of the posterior pole (the presence and number of choroidal/retinal lesions, vascular inflammation and papillitis), and global assessment from both (patient and physician). From all the variables studied in the multivariate model, anterior chamber cell grade, vitreous haze, central macular edema, inflammatory vessel sheathing, papillitis, choroidal/retinal lesions and patient evaluation were included in UVEDAI. UVEDAI is an index designed to assess the global ocular inflammatory activity in patients with uveitis. It might prove worthwhile to motorize the activity of this extraarticular manifestation of some rheumatic diseases.

Concepts: Inflammation, Regression analysis, Evaluation, Medical signs, Eye, Ophthalmology, Uveitis, Vitreous humour

3

A 25-year-old man presented with painful diminution of vision (20/160), accompanied by redness, pain and floaters, over a period of 2 weeks, in his left eye. On examination, the anterior segment revealed moderate inflammation. Posterior segment examination showed a grade one vitreous haze with a fairly long live worm moving around in a haphazard and relentless manner throughout the vitreous cavity. The media was slightly hazy due to corneal oedema. The worm was clearly visible in the fundus photo taken. So we planned the patient for vitrectomy, and removal of the worm was performed under steroid cover. The worm was sent to the microbiology department for examination and it was found to be the species of Loa loa. The patient was administered a course of diethylcarbamazine and, on follow-up after 2 weeks, his vision had improved to 20/40.

Concepts: Retina, Eye, Cornea, Ophthalmology, Lens, Filariasis, Vitreous humour

3

Vision incapacitation and blindness associated with incurable retinal degeneration affect millions of people worldwide. In this study, 0.25×10(6) human bone marrow stem cells (hBM-MSCs) were transplanted epiretinally in the right eye of Royal College Surgeons (RCS) rats at the age of 28days. Epiretinally transplanted cells were identified as a thin layer of cells along vitreous cavity, in close proximity to the retina or attached to the lens capsule, up to 6weeks following transplantation. Epiretinal transplantation delayed photoreceptor degeneration and rescued retinal function up to 20weeks following cell transplantation. Visual functions remained close to normal levels in epiretinal transplantation rats. No inflammation or any other adverse effects were observed in transplanted eyes. Our findings suggest that transplantation of hBM-MSCs as a thin epiretinal layer is effective for treatment of retinal degeneration in RCS rats, and that transplanting the cells in close proximity to the retina enhances hBM-MSC therapeutic effect compared with intravitreal injection.

Concepts: Stem cell, Mesenchymal stem cell, Bone marrow, Effect, Retina, Eye, Visual perception, Vitreous humour

2

The main aims of the present study were: (1) to assess the expression and content of dipeptidyl peptidase IV (DPP-IV) in human and db/db mouse retinas, and in human vitreous fluid; and (2) to determine whether the topical administration of the DPP-IV inhibitors (DPP-IVi) would prevent retinal neurodegeneration and vascular leakage in db/db mice by reducing endogenous glucagon-like peptide 1 (GLP-1) degradation.

Concepts: Gene, Diabetes mellitus, Retina, Eye, Dipeptidyl peptidase-4, Glucagon-like peptide-1, Vitreous humour, Glucagon-like peptide 1 receptor