May 2021

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Ma J, Chen M, Ai J, Young MJ, Ge J. Enhanced migration of engrafted retinal progenitor cells into the host retina via disruption of glial barriers. Mol Vis 2021;27:300-308.Abstract
Purpose: Migration and integration remain critical challenges for stem cell replacement therapy. Glial barriers play an important role in preventing cell migration and integration. The purpose of this study was to investigate the effect and mechanisms of chondroitinase ABC on the migration of murine retinal progenitor cells (mRPCs) transplanted into the subretinal space of B6 mice. Methods: mRPCs were harvested from the neural retinas of P1 enhanced green fluorescent protein (GFP) B6 mice. Two μl containing 2 × 105 expanded RPCs alone or combined with chondroitinase ABC in suspension were injected into the subretinal space of the recipient B6 mice. Immunohistochemistry was performed on the recipient B6 retinas to evaluate the glial barrier formation and migration of the mRPCs. Western blotting was also used to check the expression of the glial barriers. Results: Glial fibrillary acidic protein (GFAP) and vimentin could be seen around the transplanted mRPCs in the B6 mice. Formation of glial barriers prevented the migration of donor cells into the retinal layers. Chondroitinase ABC promoted the migration and survival rates of the engrafted retinal progenitor cells in the retinal layers of recipient B6 mice. Injection induced upregulation of GFAP, chondroitin, and CD44 expression. Chondroitinase ABC disrupted the glial barriers. The CD44 around the mRPCs was much lower in the chondroitinase group. However, the CD44 in the retinal layers was considerably higher in the chondroitinase group. With the employment of chondroitinase ABC, more cells migrated into the outer nuclear layer or inner nuclear layer. The chondroitin and CD44 expression decreased 3 weeks after transplantation in the chondroitinase ABC group. Conclusions: Chondroitinase ABC degraded glial barriers and enhanced the migration of transplanted mouse retinal progenitor cells. Chondroitinase ABC may also have induced activation of the CD44 signaling pathway to exert the effect.
Ma KK, Ong Tone S, Chodosh J, Saeed HN. Ochrobactrum anthropi Keratitis in a Boston Type 1 Keratoprosthesis Recipient. Cornea 2021;40(5):662-663.Abstract
PURPOSE: To report a case of Ochrobactrum anthropi keratitis in an eye with a Boston type 1 keratoprosthesis. METHODS: This is a case report and review of the literature. RESULTS: A 78-year-old man with a history of implantation of a Boston type 1 keratoprosthesis in the left eye presented for a routine follow-up with no acute complaints. In the left eye, visual acuity was 20/60 and slit-lamp examination revealed a 1.5-mm inferotemporal corneal infiltrate adjacent to the optic stem. Corneal cultures grew abundant O. anthropi. After 7 weeks of topical antimicrobial therapy and placement of a temporary tarsorrhaphy, the keratitis resolved. CONCLUSIONS: Ochrobactrum anthropi is an organism associated with indwelling medical devices and can be pathogenic in eyes with implanted keratoprostheses.
Mukharesh L, Chwalisz BK. Neuro-ophthalmic Complications of Immune-Checkpoint Inhibitors. Semin Ophthalmol 2021;36(4):241-249.Abstract
Immune checkpoint inhibitors (ICIs) have revolutionized the field of oncology by modulating the immune cell-cancer cell interaction and thereby promoting immune system disinhibition in order to target several types of malignancies. There are three classes of immune checkpoint inhibitors (ICIs): anti-cytotoxic T-lymphocyte associated antigen 4 (CTLA-4), anti-programmed cell death protein-1 (PD-1), and anti-programmed cell death ligand-1 (PD-L1).It is not uncommon for physicians across all specialties to encounter a patient with a history of malignancy and ICI exposure, necessitating familiarity with their potential complications. In this review article, we discuss the most common immune-related adverse events (irAEs) pertaining to the central and peripheral nervous systems and their potential afferent and efferent neuro-ophthalmic manifestations. Early recognition and treatment of these irAEs, and discontinuation of the offending ICI are all critical steps to prevent morbidity and mortality.
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Oke I, Vanderveen D. Machine Learning Applications in Pediatric Ophthalmology. Semin Ophthalmol 2021;36(4):210-217.Abstract
Purpose : To describe emerging applications of machine learning (ML) in pediatric ophthalmology with an emphasis on the diagnosis and treatment of disorders affecting visual development. Methods : Literature review of studies applying ML algorithms to problems in pediatric ophthalmology. Results : At present, the ML literature emphasizes applications in retinopathy of prematurity. However, there are increasing efforts to apply ML techniques in the diagnosis of amblyogenic conditions such as pediatric cataracts, strabismus, and high refractive error. Conclusions : A greater understanding of the principles governing ML will enable pediatric eye care providers to apply the methodology to unexplored challenges within the subspecialty.
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Perepelkina T, Fulton AB. Artificial Intelligence (AI) Applications for Age-Related Macular Degeneration (AMD) and Other Retinal Dystrophies. Semin Ophthalmol 2021;36(4):304-309.Abstract
Artificial intelligence (AI), with its subdivisions (machine and deep learning), is a new branch of computer science that has shown impressive results across a variety of domains. The applications of AI to medicine and biology are being widely investigated. Medical specialties that rely heavily on images, including radiology, dermatology, oncology and ophthalmology, were the first to explore AI approaches in analysis and diagnosis. Applications of AI in ophthalmology have concentrated on diseases with high prevalence, such as diabetic retinopathy, retinopathy of prematurity, age-related macular degeneration (AMD), and glaucoma. Here we provide an overview of AI applications for diagnosis, classification, and clinical management of AMD and other macular dystrophies.
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Rageh A, Ashraf M, Fleming A, Silva PS. Automated Microaneurysm Counts on Ultrawide Field Color and Fluorescein Angiography Images. Semin Ophthalmol 2021;36(4):315-321.Abstract
BACKGROUND: The severity and extent of microaneurysms (MAs) have been used to determine diabetic retinopathy (DR) severity and estimate the risk of DR progression over time. The recent introduction of ultrawide field (UWF) imaging has allowed ophthalmologists to readily image nearly the entire retina. Manual counting of MAs, especially on UWF images, is laborious and time-consuming, limiting its potential use in clinical settings. Automated MA counting techniques are potentially more accurate and reproducible compared to manual methods. METHOD: Review of available literature on current techniques of automated MA counting techniques on both ultrawide field (UWF) color images (CI) and fluorescein angiography (FA) images. RESULTS: Automated MA counting techniques on UWF images are still in the early phases of development with UWF-FA counts being further along. Early studies have demonstrated that these techniques are accurate and reproducible. CONCLUSION: Automated techniques may be an appropriate option for detecting and quantifying MAs on UWF images, especially in eyes with earlier DR severity. Larger studies are needed to appropriately validate these techniques and determine if they add substantially to clinical practice compared to standard DR grading.
Reshef ER, Bleier BS, Freitag SK. The Endoscopic Transnasal Approach to Orbital Tumors: A Review. Semin Ophthalmol 2021;36(4):232-240.Abstract
Historically, surgical access to orbital tumors has required a transcutaneous, transconjunctival or transcranial approach. Resection of orbital tumors is notoriously challenging due to the surrounding dense network of critical structures in a confined bony cavity. Advances in endoscopic endonasal surgery, initially used for sinonasal and skull base conditions, have allowed for expansion of its applications beyond the sinorbital interface. In the past decade, the evolution of techniques has enabled a purely endoscopic, minimally invasive approach to medially located orbital pathology with good outcomes. With experience and multidisciplinary collaboration between orbit and rhinologic surgeons, this has expanded to allow for a safe and effective transnasal approach to nearly all regions of the orbit with or without assistance from the orbital side. This review summarizes the relevant anatomy, variations of surgical approaches, and literature regarding outcomes of the endoscopic endonasal approach to orbital tumors.
Rossin EJ, Sobrin L, Kim LA. Single-cell RNA sequencing: An overview for the ophthalmologist. Semin Ophthalmol 2021;36(4):191-197.Abstract
Understanding the molecular composition of pathogenic tissues is a critical step in understanding the pathophysiology of disease and designing therapeutics. First described in 2009, single cell RNA sequencing (scRNAseq) is a methodology whereby thousands of cells are simultaneously isolated into individual micro-environments that can be altered experimentally and the genome-wide RNA expression of each cell is captured. It has undergone significant technological improvement over the last decade and gained tremendous popularity. scRNAseq is an improvement over prior pooled RNA analyses which cannot identify the cellular composition and heterogeneity of a tissue of interest. This new approach offers new opportunity for new discovery, as tissue samples can now be sub-categorized into groups of cell types based on genome-wide gene expression in an unbiased fashion. As ophthalmologists, we are uniquely positioned to obtain pathologic samples from the eye for further study. ScRNAseq has already been applied in ophthalmology to characterize retinal tissue, and it may offer the key to understanding various pathological processes in the future.
Rubinfeld RS, Gum GG, Talamo JH, Parsons EC. The Effect of Sodium Iodide on Stromal Loading, Distribution and Degradation of Riboflavin in a Rabbit Model of Transepithelial Corneal Crosslinking. Clin Ophthalmol 2021;15:1985-1994.Abstract
Purpose: To evaluate effects of sodium iodide (NaI) on riboflavin concentration in corneal stroma before and during ultraviolet A (UVA) light exposure using a novel transepithelial corneal collagen crosslinking (CXL) procedure (EpiSmart CXL system, CXL Ophthalmics, Encinitas CA). Methods: Riboflavin solutions with NaI (Ribostat, CXL Ophthalmics, Encinitas CA) and without NaI were used for CXL in rabbits using EpiSmart. A pilot study determined sufficient riboflavin loading time. Four rabbits were dosed and monitored. Riboflavin fluorescence intensity was assessed from masked slit-lamp photos. A 12 min loading time was selected. Sixteen additional rabbits received the two formulae in contralateral eyes for CXL. Riboflavin uptake was assessed at 0, 10, 15, 20, 25, and 30 min of UVA exposure using a scale for riboflavin fluorescence previously validated against stromal concentration. Post sacrifice, corneal stromal samples were analyzed for concentrations of riboflavin and riboflavin 5'-phosphate. Results: Eyes dosed with NaI riboflavin had higher riboflavin grades compared to eyes dosed with the NaI-free riboflavin formulation immediately after riboflavin loading and persisting throughout UVA exposure, with significantly higher (P < 0.01 to < 0.05) riboflavin grades from 15 through 25 min of UVA exposure. Riboflavin grades decreased more slowly in eyes dosed with NaI riboflavin through 25 minutes of UVA exposure. Minor conjunctival irritation was noted with or without NaI. Conclusion: The addition of NaI to riboflavin solution is associated with increased riboflavin concentration in corneal stroma throughout a clinically relevant time course of UVA exposure. This effect may be a combination of enhanced epithelial penetration and reduced riboflavin photodegradation and should enhance intrastromal crosslinking.
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Saitakis G, Chwalisz BK. The neurology of IGG4-related disease. J Neurol Sci 2021;424:117420.Abstract
PURPOSE OF REVIEW: IgG4-related disease (IgG4-RD) is emerging as a fibro-inflammatory entity affecting multiple organs, including manifold neurologic manifestations. This review discusses general characteristics of IgG4-RD neurologic disease including epidemiology, histology, clinical picture and treatment approaches. RECENT FINDINGS: IgG4-RD is increasingly recognized as an important underlying pathophysiology in multiple disorders of neurologic interest, including orbital inflammation, infundibulo-hypophysitis, hypertrophic pachymeningitis, and even in rare cases CNS parenchymal disease and cranial vascular involvement. These were previously considered idiopathic and unrelated to any systemic disease but now known to share a common histopathology. New knowledge regarding the pathogenesis, clinical features and epidemiology of IgG4 is emerging, and new neurological manifestations continue to be described. Diagnostic progress includes CT-PET imaging, the use of flow cytometry for plasmablast quantification, and the use of reverse passive latex agglutination aiming to overcome the prozone phenomenon. Histopathologic confirmation of IgG4-RD remains the gold standard method of diagnosis but new diagnostic criteria for systemic and organ-specific disease are being proposed. Though glucorticoids remain the mainstay of therapy, relapses and incomplete recovery are frequent. Rituximab is a promising treatment in IgG4-RD that is severe, refractory or glucocorticoid dependent. Initiation of immunosuppression at an early stage of disease should be considered in order to avoid development of refractory fibrosis. SUMMARY: The current review emphasizes the neurologic manifestations of IgG4-RD.
Scelfo C, Mantagos IS. Neurotrophic Keratopathy in Pediatric Patients. Semin Ophthalmol 2021;36(4):289-295.Abstract
Purpose: This review provides an overview of the causes and treatment of neurotrophic keratopathy in the pediatric population.Methods: A thorough review of the current literature discussing neurotrophic keratopathy was conducted then summarized.Results:Fourty-nine papers were reviewed. Congenital and acquired causes of neurotrophic keratopathy exist in the pediatric population. Both medical and surgical approaches to treatment have been trialed, albeit to a limited extent, in pediatric patients. Conservative treatment includes topical lubrication and antibiotics to prevent concurrent infectious ulcer formation. Various neurotrophic factors have been trialed in the form of serum drops to restore corneal sensation when conservative measures fail. Surgically, different corneal neurotization techniques have been developed whereby a donor nerve is routed to the anesthetized cornea to restore innervation and sensation. Conclusions: Advances in the treatment of neurotrophic keratopathy have made corneal reinnervation and restoration of vision more easily attainable in pediatric patients.
Shoshany TN, Chinn RN, Staffa SJ, Bishop K, Michalak S, Hunter DG. Identifying Characteristics Predictive of Lost-to-follow-up (LTFU) Status in Amblyopia. Am J Ophthalmol 2021;Abstract
PURPOSE: To identify demographic and disease-related characteristics predictive of LTFU status in amblyopia treatment and create a risk model for predicting LTFU status. DESIGN: Retrospective cohort study METHODS: Setting: Single center, ophthalmology department at Boston Children's Hospital (BCH). PATIENTS: 2037 patients treated for amblyopia at BCH between 2010-2014. OBSERVATION PROCEDURE: LTFU was defined as patients who did not return after initial visit, excluding those who came for second opinion. Multiple variables were tested for association with LTFU status. OUTCOME MEASURE: Odds ratio of LTFU risk associated with each variable. Multivariate logistic regression was used to create a risk score for predicting LTFU status. RESULTS: A large proportion of patients (23%) were LTFU after first visit. Older age, non-white race, lack of insurance, previous glasses or atropine treatment, and longer requested follow-up intervals were independent predictors of LTFU status. A multivariable risk score was created to predict probability of LTFU (AUC 0.68). CONCLUSIONS: Our comprehensive amblyopia database allows us to predict which patients are more likely to be LTFU after baseline visit, and develop strategies to mitigate these effects. These findings may help with practice efficiency and improve patient outcomes in the future by transitioning these analyses to an electronic medical record that could be programmed to provide continually updated decision support for individual patients based on large datasets.
Silva RNE, Chiou CA, Wang M, Devlin J, Li D, Lovelace S, Wang H, Greenstein SH, Brauner SC, Shen LQ. Quantification of the Peripapillary Microvasculature in Eyes with Glaucomatous Paracentral Visual Field Loss. Ophthalmol Glaucoma 2021;4(3):286-294.Abstract
PURPOSE: To quantify abnormalities in the peripapillary microvasculature in eyes with primary open-angle glaucoma (POAG) and paracentral visual field (VF) loss. DESIGN: Prospective, cross-sectional study. PARTICIPANTS: Thirty-three POAG patients, including 15 with paracentral VF loss and 18 with peripheral VF loss, and 31 control participants underwent swept-source OCT angiography (OCTA) of the peripapillary region. METHODS: The POAG groups were matched by VF mean deviation (MD). The peripapillary microvasculature from the internal limiting membrane to the retinal nerve fiber layer (RNFL) interface was quantified within a 0.70-mm annulus around Bruch's membrane opening after removal of large vessels. Both vessel density (VD) and the integrated OCTA by ratio analysis signal (IOS) suggestive of flow were measured. Regional VD and IOS were measured from the affected hemisphere corresponding to the VF hemifield of more severe loss, which was used to calculate the paracentral total deviation (PaTD), or total deviation within the central 10°. One eye per participant was included. MAIN OUTCOME MEASURES: Difference in peripapillary OCTA measurements between paracentral and peripheral VF loss groups and correlation of peripapillary VD and IOS with PaTD. RESULTS: The POAG groups had matched VF MD (-3.1 ± 2.5 dB paracentral vs. -2.3 ± 2.0 dB peripheral; P = 0.31), did not differ in average RNFL thickness (71.1 ± 14.7 μm vs. 78.1 ± 15.0 μm; P = 0.55), but differed in age (59.2 ± 9.6 years paracentral vs. 67.4 ± 6.6 years peripheral; P = 0.02). Compared with control participants, both paracentral and peripheral VF loss groups showed reduced VD (P < 0.001 and P = 0.009, respectively) and IOS (P < 0.001 and P = 0.01, respectively) in the affected hemisphere. Compared with POAG eyes with peripheral VF loss, the paracentral group showed reduced peripapillary VD (38.0 ± 2.0%, 35.0 ± 2.2%, respectively; P = 0.001) and IOS (44.3 ± 3.1%, 40.4 ± 4.0%, respectively; P = 0.02) in the affected hemisphere. Among all POAG eyes, peripapillary VD and IOS of the affected hemisphere correlated significantly with functional measurement of paracentral loss (PaTD, r = 0.40, P = 0.02; r = 0.45, P = 0.008; respectively). These correlations remained significant after adjusting for age (r = 0.41, P = 0.02; r = 0.47, P = 0.01; respectively). CONCLUSIONS: Regional peripapillary microvasculature showed decreased VD and flow in POAG with paracentral loss, supporting its importance in this glaucoma subtype.
Simpson FC, McTiernan CD, Islam MM, Buznyk O, Lewis PN, Meek KM, Haagdorens M, Audiger C, Lesage S, Gueriot F-X, Brunette I, Robert M-C, Olsen D, Koivusalo L, Liszka A, Fagerholm P, Gonzalez-Andrades M, Griffith M. Collagen analogs with phosphorylcholine are inflammation-suppressing scaffolds for corneal regeneration from alkali burns in mini-pigs. Commun Biol 2021;4(1):608.Abstract
The long-term survival of biomaterial implants is often hampered by surgery-induced inflammation that can lead to graft failure. Considering that most corneas receiving grafts are either pathological or inflamed before implantation, the risk of rejection is heightened. Here, we show that bioengineered, fully synthetic, and robust corneal implants can be manufactured from a collagen analog (collagen-like peptide-polyethylene glycol hybrid, CLP-PEG) and inflammation-suppressing polymeric 2-methacryloyloxyethyl phosphorylcholine (MPC) when stabilized with the triazine-based crosslinker 4-(4,6-Dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride. The resulting CLP-PEG-MPC implants led to reduced corneal swelling, haze, and neovascularization in comparison to CLP-PEG only implants when grafted into a mini-pig cornea alkali burn model of inflammation over 12 months. Implants incorporating MPC allowed for faster nerve regeneration and recovery of corneal sensation. CLP-PEG-MPC implants appear to be at a more advanced stage of regeneration than the CLP-PEG only implants, as evidenced by the presence of higher amounts of cornea-specific type V collagen, and a corresponding decrease in the presence of extracellular vesicles and exosomes in the corneal stroma, in keeping with the amounts present in healthy, unoperated corneas.
Styliadis C, Leung R, Özcan S, Moulton EA, Pang E, Taylor MJ, Papadelis C. Atypical spatiotemporal activation of cerebellar lobules during emotional face processing in adolescents with autism. Hum Brain Mapp 2021;42(7):2099-2114.Abstract
Autism spectrum disorder (ASD) is characterized by social deficits and atypical facial processing of emotional expressions. The underlying neuropathology of these abnormalities is still unclear. Recent studies implicate cerebellum in emotional processing; other studies show cerebellar abnormalities in ASD. Here, we elucidate the spatiotemporal activation of cerebellar lobules in ASD during emotional processing of happy and angry faces in adolescents with ASD and typically developing (TD) controls. Using magnetoencephalography, we calculated dynamic statistical parametric maps across a period of 500 ms after emotional stimuli onset and determined differences between group activity to happy and angry emotions. Following happy face presentation, adolescents with ASD exhibited only left-hemispheric cerebellar activation in a cluster extending from lobule VI to lobule V (compared to TD controls). Following angry face presentation, adolescents with ASD exhibited only midline cerebellar activation (posterior IX vermis). Our findings indicate an early (125-175 ms) overactivation in cerebellar activity only for happy faces and a later overactivation for both happy (250-450 ms) and angry (250-350 ms) faces in adolescents with ASD. The prioritized hemispheric activity (happy faces) could reflect the promotion of a more flexible and adaptive social behavior, while the latter midline activity (angry faces) may guide conforming behavior.
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Tomkins-Netzer O, Lightman SL, Burke AE, Sugar EA, Lim LL, Jaffe GJ, Altaweel MM, Kempen JH, Holbrook JT, Jabs DA, and Group MSTTF-up SR. Seven-Year Outcomes of Uveitic Macular Edema: The Multicenter Uveitis Steroid Treatment Trial and Follow-up Study Results. Ophthalmology 2021;128(5):719-728.Abstract
PURPOSE: To evaluate the long-term outcomes of uveitic macular edema (ME). DESIGN: Longitudinal follow-up of a cohort of participants in a randomized clinical trial. PARTICIPANTS: A total of 248 eyes of 177 participants with uveitic ME enrolled in the Multicenter Uveitis Steroid Treatment (MUST) Trial and Follow-up Study. METHODS: OCT measurements, taken at baseline and annually, were graded by reading center graders masked to clinical data. Macular edema was defined as a center macular thickness (CMT) ≥240 μm on time-domain OCT or time-domain OCT equivalent. Resolution of ME was defined as normalization of macular thickness on OCT. Relapse of ME was defined as increase in macular thickness to ≥240 μm in an eye that previously had resolution. Visual acuity was measured at each visit with logarithmic visual acuity charts. MAIN OUTCOME MEASURES: Resolution and relapse of ME. Visual acuity. RESULTS: Among 227 eyes with ME followed ≥1 year, the cumulative percent of eyes with ME resolving at any point during 7 years was 94% (95% confidence interval [CI], 89-97). Epiretinal membranes on OCT were associated with a lower likelihood of ME resolution (hazard ratio [HR], 0.74; 95% CI, 0.55-1.01; P = 0.05). Among 177 eyes with resolved ME, the cumulative percent with relapse within 7 years was 43% (95% CI, 32-51). Eyes in which ME resolved gained a mean of 6.24 letters (95% CI, 4.40-8.09; P < 0.001) compared with eyes that remained free from ME during the 1-year follow-up intervals, whereas eyes in which ME did not resolve experienced no gain in vision (mean change -1.30 letters; 95% CI, -2.70 to 0.09; P = 0.065), and eyes that developed ME during the year (incident or relapsed) experienced a mean loss of -8.65 letters (95% CI, -11.5 to -5.84, P < 0.001). CONCLUSIONS: Given sufficient time and treatment, nearly all uveitic ME resolves, but episodes of relapse were common. Visual acuity results were better among eyes with resolved ME, suggesting that control of inflammation and resolution of ME might be visually relevant treatment targets.
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Wang M, Garg I, Miller JB. Wide Field Swept Source Optical Coherence Tomography Angiography for the Evaluation of Proliferative Diabetic Retinopathy and Associated Lesions: A Review. Semin Ophthalmol 2021;36(4):162-167.Abstract
Retinal imaging remains the mainstay for monitoring and grading diabetic retinopathy. The gold standard for detecting proliferative diabetic retinopathy (PDR) requiring treatment has long been the seven-field stereoscopic fundus photography and fluorescein angiography. In the past decade, ultra-wide field fluorescein angiography (UWF-FA) has become more commonly used in clinical practice for the evaluation of more advanced diabetic retinopathy. Since its invention, optical coherence tomography (OCT) has been an important tool for the assessment of diabetic macular edema; however, OCT offered little in the assessment of neovascular changes associated with PDR until OCT-A became available. More recently, swept source OCT allowed larger field of view scans to assess a variety of DR lesions with wide field swept source optical coherence tomography (WF-SS-OCTA). This paper reviews the role of WF-SS-OCTA in detecting neovascularization of the disc (NVD), and elsewhere (NVE), microaneurysms, changes of the foveal avascular zone (FAZ), intraretinal microvascular abnormalities (IRMA), and capillary non-perfusion, as well as limitations of this evolving technology.
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Yuan A, Ma K, Sharifi S, Pineda R. Biomechanical testing of flanged polypropylene sutures in scleral fixation. Am J Ophthalmol 2021;Abstract
OBJECTIVE: To optimize the flanged belt-loop technique of scleral fixation through biomechanical testing and report clinical outcomes of resultant modifications. DESIGN: Experimental study. METHODS: The force to disinsert flanged polypropylene suture from human cadaveric sclera was assessed using a tensile testing machine and compared to the breaking strengths of 9-0 and 10-0 polypropylene. The effects of modifying suture gauge (5-0, 6-0, 7-0 or 8-0), amount of suture cauterized (0.5 or 1.0mm), and sclerotomy size (27-, 30-, 32-, 33-gauge) were investigated. Belt-loop intrascleral fixation using 6-0 and 7-0 polypropylene with 30- and 32-gauge needles respectively was performed in 5 patients. MAIN OUTCOME MEASURES: Flanged suture disinsertion force in cadaveric sclera. RESULTS: The average force to disinsert a flange created by melting 1.0mm of 5-0, 6-0, 7-0 and 8-0 polypropylene suture from human cadaveric sclera via 27-, 30-, 32- and 33-gauge needle sclerotomies was 3.0 ± 0.5N, 2.1 ± 0.3N, 0.9 ± 0.2N and 0.4 ± 0.1N respectively. The disinsertion forces for flanges formed by melting 0.5mm of the same gauges were 72-79% lower (p < 0.001). In comparison, the breaking strengths of 9-0 and 10-0 polypropylene were 1.0 ± 0.2N and 0.5 ± 0.0N. Belt-loop fixation using 6-0 and 7-0 polypropylene with 30- and 32-gauge sclerotomies demonstrated good outcomes at 6 months. CONCLUSIONS: The flanged belt-loop technique is a biomechanically sound method of scleral fixation using 1.0mm flanges of 5-0 to 7-0 polypropylene paired with 27-, 30- and 32- gauge sclerotomies. In contrast, 8-0 polypropylene and 0.5 mm flanges of any suture gauge will likely be unstable with this technique.
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Zhu GH, Azharuddin M, Islam R, Rahmoune H, Deb S, Kanji U, Das J, Osterrieth J, Aulakh P, Ibrahim-Hashi H, Manchanda R, Nilsson PH, Mollnes TE, Bhattacharyya M, Islam MM, Hinkula J, Slater NKH, Patra HK. Innate Immune Invisible Ultrasmall Gold Nanoparticles-Framework for Synthesis and Evaluation. ACS Appl Mater Interfaces 2021;13(20):23410-23422.Abstract
Nanomedicine is seen as a potential central player in the delivery of personalized medicine. Biocompatibility issues of nanoparticles have largely been resolved over the past decade. Despite their tremendous progress, less than 1% of applied nanosystems can hit their intended target location, such as a solid tumor, and this remains an obstacle to their full ability and potential with a high translational value. Therefore, achieving immune-tolerable, blood-compatible, and biofriendly nanoparticles remains an unmet need. The translational success of nanoformulations from bench to bedside involves a thorough assessment of their design, compatibility beyond cytotoxicity such as immune toxicity, blood compatibility, and immune-mediated destruction/rejection/clearance profile. Here, we report a one-pot process-engineered synthesis of ultrasmall gold nanoparticles (uGNPs) suitable for better body and renal clearance delivery of their payloads. We have obtained uGNP sizes of as low as 3 nm and have engineered the synthesis to allow them to be accurately sized (almost nanometer by nanometer). The synthesized uGNPs are biocompatible and can easily be functionalized to carry drugs, peptides, antibodies, and other therapeutic molecules. We have performed in vitro cell viability assays, immunotoxicity assays, inflammatory cytokine analysis, a complement activation study, and blood coagulation studies with the uGNPs to confirm their safety. These can help to set up a long-term safety-benefit framework of experimentation to reveal whether any designed nanoparticles are immune-tolerable and can be used as payload carriers for next-generation vaccines, chemotherapeutic drugs, and theranostic agents with better body clearance ability and deep tissue penetration.

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