Delineating three-dimensional behavior of uveal melanoma cells under anchorage independent or dependent conditions.

BACKGROUND: Although rare, uveal melanoma (UM) is a life-threatening malignancy. Understanding its biology is necessary to improve disease outcome. Three-dimensional (3D) in vitro culture methods have emerged as tools that incorporate physical and spatial cues that better mimic tumor biology and in turn deliver more predictive preclinical data. Herein, we comprehensively characterize UM cells under different 3D culture settings as a suitable model to study tumor cell behavior and therapeutic intervention. METHODS: Six UM cell lines were tested in two-dimensional (2D) and 3D-culture conditions. For 3D cultures, we used anchorage-dependent (AD) methods where cells were embedded or seeded on top of basement membrane extracts and anchorage-free (AF) methods where cells were seeded on agarose pre-coated plates, ultra-low attachment plates, and on hanging drops, with or without methylcellulose. Cultures were analyzed for multicellular tumor structures (MCTs) development by phase contrast and confocal imaging, and cell wellbeing was assessed based on viability, membrane integrity, vitality, apoptotic features, and DNA synthesis. Vascular endothelial growth factor (VEGF) production was evaluated under hypoxic conditions for cell function analysis. RESULTS: UM cells cultured following anchorage-free methods developed MCTs shaped as spheres. Regardless of their sizes and degree of compaction, these spheres displayed an outer ring of viable and proliferating cells, and a core with less proliferating and apoptotic cells. In contrast, UM cells maintained under anchorage-dependent conditions established several morphological adaptations. Some remained isolated and rounded, formed multi-size irregular aggregates, or adopted a 2D-like flat appearance. These cells invariably conserved their metabolic activity and conserved melanocytic markers (i.e., expression of Melan A/Mart-1 and HMB45). Notably, under hypoxia, cells maintained under 3D conditions secrete more VEGF compared to cells cultured under 2D conditions. CONCLUSIONS: Under an anchorage-free environment, UM cells form sphere-like MCTs that acquire attributes reminiscent of abnormal vascularized solid tumors. UM cells behavior in anchorage-dependent manner exposed diverse cells populations in response to cues from an enriched extracellular matrix proteins (ECM) environment, highlighting the plasticity of UM cells. This study provides a 3D cell culture platform that is more predictive of the biology of UM. The integration of such platforms to explore mechanisms of ECM-mediated tumor resistance, metastatic abilities, and to test novel therapeutics (i.e., anti-angiogenics and immunomodulators) would benefit UM care.

Filtering blue light mitigates the deleterious effects induced by the oxidative stress in human retinal pigment epithelial cells.

Age-related macular degeneration (AMD) is a major cause of blindness in elderly. It is characterized by the loss of central vision due to damaged retinal pigment epithelial (RPE) cells and photoreceptors. Blue Light (BL) exposure was proposed as a risk factor for AMD progression. We undertook this study to determine the effects of BL on the behaviour of RPE cells and their potential mitigation by BL-filtering intraocular lenses (IOL). Human RPE cells were exposed or not to BL, with the absence or presence of either a clear ultraviolet (UV)-filtering IOL (CIOL), or a yellow UV- and BL-filtering IOL (YIOL). Cells were analyzed for their oxidative stress by measuring the levels of reactive oxygen species (ROS), and their viability. BL exposure significantly increased the levels of both total cellular and mitochondrial ROS. While this increase was not affected by placing the CIOL in the BL beam, YIOL decreased the levels of both ROS reservoirs. Increased ROS production was accompanied by increased cell death which was similarly decreased when cells were protected with the YIOL. Pre-treatment of cells with N-acetylcycteine (NAC) abolished the increased cell death, suggesting that the effects of BL on cell viability were mainly due to increased levels of ROS. BL is deleterious to RPE cells due to increased oxidative stress and cell death. These effects were mitigated by filtering these radiations. The use of BL-filtering devices may represent a strategy to reduce these effects on RPE cells and delay the onset of AMD.

Cemiplimab for metastatic squamous cell carcinoma of the orbit, periocular adnexa, and thigh.

The current case presentation highlights the potential of cemiplimab, a programmed cell death protein-1 (PD-1) inhibitor, as first-line treatment for periocular metastatic cutaneous squamous cell carcinoma (SCC) without requiring curative surgery or radiotherapy. A 64-year-old male presented with a progressing 4.5 × 3.0 cm left upper eyelid lesion initially diagnosed as psoriasis. Work-up revealed cutaneous SCC with tumor invasion into extraconal fat and lacrimal gland, and metastasis to the left parotid lymph node. The patient also presented with a suspicious lesion on his left medial thigh found to be a second primary on pathology. To avoid orbital exenteration and treat the multifocal disease, the patient was started on intravenous cemiplimab immunotherapy. Following six doses, repeated FGD-PET-CT revealed a complete response of the left eyelid lesion and residual low-grade hypermetabolic activity of the left medial thigh lesion. Biopsy confirmed chronic inflammation and fibrosis with no signs of malignancy. This unique case with dual primary cutaneous SCC provides support for cemiplimab in treating locally invasive periocular SCC, and potentially abrogating the need for highly morbid exenteration procedures to preserve binocular vision.

Programmed cell death ligand-1 expression in tumor and immune cells is associated with better patient outcome and decreased tumor-infiltrating lymphocytes in uveal melanoma.

Programmed cell death-1/ligand (PD-1/PD-L1) interaction negatively regulates T cell activity. PD-L1 expression in tumor cells, antigen-presenting cells, and lymphocytes of the tumor microenvironment is associated with response to treatment with PD-1/PD-L1 inhibitors, but there is still debate on the cutoff value that correlates with responders. In uveal melanoma (UM), 40% of patients will develop liver metastases and, amongst them, 90% will succumb to their disease. The aim of this study was to analyze PD-L1 expression as a prognostic marker and as a possible therapeutic target for UM. Sixty-seven enucleated eyes from UM patients with relevant clinical information were analyzed. Univariate and multivariate analysis were used to evaluate association of PD-L1 with survival. PD-L1 expression was positive relatively to tumor cells, immune cells, and the tumor and tumor-infiltrating immune cell group scoring in 46, 34 and 55% of the cases, respectively. On univariate analysis, tumor cells and the tumor and tumor-infiltrating immune cell group PD-L1 expression was associated with a longer metastasis-free survival (P = 0.04 and P = 0.007). However, on multivariate analysis, only the tumor and tumor-infiltrating immune cell group positivity was associated with longer metastasis-free survival (P = 0.01). Furthermore, tumor cells and the tumor and tumor-infiltrating immune cell group PD-L1 expression was associated with decreased tumor-infiltrating lymphocytes (P = 0.02). PD-L1, when expressed in uveal melanoma, is associated with better patient outcome and decreased tumor-infiltrating lymphocytes. These results support the consideration of anti-PD-1/PD-L1 therapy in uveal melanoma. To determine the best cutoff value, further studies from patients enrolled in clinical trials treated with PD-1/PD-L1 inhibitors are necessary.

Peptidyl-prolyl cis-trans isomerase A - A novel biomarker of multi-episodic (recurrent) ocular toxoplasmosis.

Ocular toxoplasmosis (OT) is the most common etiology of posterior uveitis. The high incidence of macular scarring associated with OT is a leading cause of visual morbidity. Serum biomarkers of the disease would aid in its diagnosis. This study sought, for the first time, to elucidate serum biomarkers for OT by mass spectrometry. Blood samples were collected from four groups of nine patients each; toxoplasmosis IgG-with no history of uveitis, non-toxoplasmosis uveitis, first episode OT, and symptomatic recurrent OT. Serum was isolated and subjected to proteomics analysis using 2-dimensional gel electrophoresis (2D-GE) and surface-enhanced laser desorption ionization mass spectrometry (SELDI-MS). Selected proteins were further separated by SDS-PAGE and sequenced using tandem MS. Results were cross-validated with a T. gondii outbreak biomarker database that occurred in Brazil. Fifty markers of OT and 46 markers of recurrent disease were discovered by SELDI-MS of which 30 and 15, respectively, were cross-validated. 2D-GE analysis yielded 57 bands, selected based on the intensity of the bands, leading to the identification of 20 proteins. Eleven of those identified candidates were also found by SELDI-MS. Four candidates were chosen for immunoblotting. One serum protein, peptidyl-prolyl cis-trans isomerase A (PPIA), was confirmed as a biomarker of multi-episodic OT by immunoblotting in patients. PPIA can identify the patient with active recurrent OT from acute OT, other forms of uveitis and other parasitic infections. A validated PPIA assay may have a role in the diagnosis of the atypical OT patient before more invasive anterior chamber or vitreous tap is performed for PCR analysis or for Goldmann-Witner coefficient calculations. Base-line PPIA levels need to be studied to understand its possible use when deciding for prophylactic antibiotic use in the immunosuppressed sero-positive patient.

Blue-light filtering alters angiogenic signaling in human retinal pigmented epithelial cells culture model.

BACKGROUND: Light exposure and more specifically the spectrum of blue light contribute to the oxidative stress in Age-related macular degeneration (AMD). The purpose of the study was to establish whether blue light filtering could modify proangiogenic signaling produced by retinal pigmented epithelial (RPE) cells under different conditions simulating risk factors for AMD. METHODS: Three experiments were carried out in order to expose ARPE-19 cells to white light for 48 h with and without blue light-blocking filters (BLF) in different conditions. In each experiment one group was exposed to light with no BLF protection, a second group was exposed to light with BLF protection, and a control group was not exposed to light. The ARPE-19 cells used in each experiment prior to light exposure were cultured for 24 h as follows: Experiment 1) Normoxia, Experiment 2) Hypoxia, and Experiment 3) Lutein supplemented media in normoxia. The media of all groups was harvested after light exposure for sandwich ELISA-based assays to quantify 10 pro-angiogenic cytokines. RESULTS: A significant decrease in angiogenin secretion levels and a significant increase in bFGF were observed following light exposure, compared to dark conditions, in both normoxia and hypoxia conditions. With the addition of a blue light-blocking filter in normoxia, a significant increase in angiogenin levels was observed. Although statistical significance was not achieved, blue light filters reduce light-induced secretion of bFGF and VEGF to near normal levels. This trend is also observed when ARPE-19 cells are grown under hypoxic conditions and when pre-treated with lutein prior to exposure to experimental conditions. CONCLUSIONS: Following light exposure, there is a decrease in angiogenin secretion by ARPE-19 cells, which was abrogated with a blue light - blocking filter. Our findings support the position that blue light filtering affects the secretion of angiogenic factors by retinal pigmented epithelial cells under normoxic, hypoxic, and lutein-pretreated conditions in a similar manner.

Pretreatment of RPE Cells with Lutein Can Mitigate Bevacizumab-Induced Increases in Angiogenin and bFGF.

PURPOSE: To determine whether pretreatment of retinal pigmented epithelial (RPE) cells with lutein can affect the response of cells to bevacizumab therapy. METHODS: One human RPE cell line (ARPE-19) was used for all experiments. The cells were treated with lutein in different concentrations (0.01, 0.1, 1, 10, or 100 µg/ml). After 24 h, all plates were treated with bevacizumab (0.25 mg/ml). Media were harvested 24 h later for sandwich ELISA-based angiogenesis arrays. A Quantibody Human Angiogenesis Array was used in order to quantify the secretion of the following 10 proangiogenic cytokines: angiogenin, ANG2, EGF, bFGF, HB-EGF, PDGF-BB, leptin, PIGF, HGF and VEGF. RESULTS: Treatment with bevacizumab alone led to a significant decrease in VEGF, as well as a significant increase in angiogenin and bFGF. Pretreatment with 0.1 and 1.0 µg/ml of lutein led to significant decreases in both bFGF and angiogenin following treatment with bevacizumab compared to bevacizumab treatment alone. Lutein alone did not modify the secretion of proangiogenic cytokines. CONCLUSIONS: Pretreatment of human RPE cells in culture with specific doses of lutein prior to bevacizumab treatment mitigated the increase in bFGF and angiogenin caused by bevacizumab monotherapy.

Eyelid Mycetoma Masquerading as Sebaceous Carcinoma.

A 56-year-old Asian woman presented with an upper eyelid mass. The lesion was exposed after eversion of the eyelid revealing a thickened tarsus with yellowish areas. Working diagnosis was sebaceous carcinoma. Biopsy was performed. Histopathological studies showed a mycotic eumycetoma with Splendore-Hoeppli phenomena and - microbiologic cultures grew Scedosporium apiospermum. The patient was started on voriconazole 200 mg po bid with adequate serum levels. A complete response was observed after 18 weeks of voriconazole therapy. To the best of our knowledge, this is the first published case of S. apiospermum eumycotic mycetoma of the eyelid. It is important to consider mycotic infection in the differential diagnosis of eyelid tumors even in healthy patients.

Evaluating the presence of Toxoplasma gondii in peripheral blood of patients with diverse forms of uveitis.

The purpose of this study was to evaluate the presence of Toxoplasmosis gondii in samples of peripheral blood from patients with varying etiologies of uveitis. Whole blood from patients with different forms of uveitis was tested for the presence of T. gondii using real-time PCR targeting the well-characterized 529 bp fragment. Extracted DNA was both frozen. Thirty-one patients were included in the current study and grouped as follows: acute toxoplasmosis (n = 10); toxoplasmic retinal scars (n = 9); non-infectious etiologies of uveitis (n = 6); and IgG negative for toxoplasmosis (n = 6). In total, only two patients were shown to have circulating T. gondii in peripheral blood; both of these patients were IgG positive for toxoplasmosis, were receiving immunosuppressive therapy for autoimmune uveitis, and had no clinical features of toxoplasmosis. T. gondii was identified in peripheral blood of some immunosuppressed patients. No other patients, including those with acute toxoplasmosis, had circulating parasites in peripheral blood.

Conjunctival Melanoma With Morphologic Diversity and Orbital Invasion.

A 68-year-old male with a previous history of 3 dysplastic skin nevi was referred to ophthalmology for a 1-year history of a progressive growth of a firm nodule in the lower left eyelid. Examination revealed a firm nodule in the inferior anterior orbit and mild conjunctival pigmentation on the left inferior fornix. A conjunctival incisional biopsy was taken, showing a melanoma. Because of the infiltration by the mass of the orbit on magnetic resonance imaging, an exenteration was performed. Histopathological analysis showed a unique conjunctival melanoma showing morphological diversity; specifically, a pattern characteristic of conjunctival melanoma, and the concurrent presence of staghorn patterns, signet-ring cells, and rosettoid patterns. Seven years of follow-up shows that the patient is alive with no further metastasis or recurrence. This report represents the first documented case of multiple morphologic patterns within a conjunctival melanoma.

Immunohistochemical Analysis of PDGFR-α, PDGFR-ß and c-Abl in Retinoblastoma: Potential Therapeutic Targets.

BACKGROUND: Our laboratory previously reported that imatinib mesylate (IM) has an inhibitory effect on two retinoblastoma (Rb) cell lines in vitro. AIMS: The purpose of this project was to determine the immunoexpression of platelet-derived growth factor receptor (PDGFR)-α, PDGFR-ß and c-Abl in 61 human samples of Rb to determine if IM-sensitive receptors are present. Additionally, this paper seeks to establish a correlation between the expression of PDGFR, c-Abl and the histopathological prognosis. METHODS: Sixty-one paraffin-embedded Rbs were collected from the Henry C. Witelson Ocular Pathology Registry. PDGFR-α, PDGFR-ß and c-Abl immunostaining was performed according to the protocol provided by Ventana Medical System Inc. Immunoreactivity was correlated with the presence or absence of invasion into the choroid and optic nerve. RESULTS: Overall, c-Abl expression was identified in 50 out of 61 specimens (81.97%), PDGFR-α was identified in 20 out of 60 specimens (33.33%) and PDGFR-ß expression was identified in 57 out of 61 specimens (93.44%). Histopathological prognosis was not correlated with immunoreactivity except in the case of PDGFR-ß. CONCLUSIONS: Rb is a cancer that expresses PDGFR-α, PDGFR-ß and c-Abl, which are known targets of IM. These markers may be responsible for the documented therapeutic effect of IM on Rb cell lines.

Pericyte Status in Routinely Discarded Vitrectomy Samples May Be an Early Marker of Diabetic Retinopathy.

BACKGROUND: Diabetic retinopathy (DR) is the leading cause of blindness among the working-age population. The earliest morphological manifestation of the disease is pericyte loss, as shown by animal models. AIMS: The purpose of this study was to evaluate the presence of pericytes in vitreous samples (VS) from diabetic and nondiabetic patients. METHODS: VS from 125 patients with and without diabetes were analyzed. Thirty-three of the VS contained blood vessels and were therefore included in further analysis. Pericyte status was evaluated using α-smooth muscle actin and quantified using the following scoring system: total loss (3), >50% loss (2), <50% loss (1), and no loss (0). RESULTS: Of the 33 VS, 29 samples were from patients with diabetes and 4 from nondiabetic patients. Six diabetic cases had a score of 1, 8 diabetic cases had a score of 2, and 15 cases had a score of 3. A positive correlation between glycemia levels and pericyte loss was observed (p = 0.0016; Spearman's r = 0.61). Moreover, all nondiabetic cases had a score of 0 (sensitivity and specificity = 100%). CONCLUSION: Pericyte loss in VS might be a sensitive and specific marker of DR that correlates with glycemia levels. Furthermore, VS, which are currently discarded, may contain valuable information for diabetic management.

Expression of SIRT2 and SIRT6 in retinoblastoma.

PURPOSE: SIRT2 and SIRT6 are members of the sirtuin family and are associated with cancer development and progression in certain tumours, but their expression in retinoblastoma has not been studied. The primary objective of our study was to determine the expression of SIRT2 and SIRT6 in human retinoblastoma cases. METHODS: Eighteen formalin-fixed paraffin-embedded blocks of retinoblastoma cases from the Ocular Pathology Registry at the Henry C. Witelson Ocular Pathology Laboratory were obtained, classified and immunostained for SIRT2 and SIRT6 using mouse monoclonal antibodies. RESULTS: Sixteen cases were poorly differentiated retinoblastoma cases. SIRT2 and SIRT6 were expressed in all cases of retinoblastoma although differences in the staining intensity were found between cases. SIRT2 and SIRT6 expression was also observed in various normal structures of the remaining ocular tissue. CONCLUSIONS: SIRT2 and SIRT6 are expressed in retinoblastoma, as well as in some normal ocular structures. While precise roles of these proteins must still be determined in retinoblastoma, their expression profiles suggest that further functional studies of both SIRT2 and SIRT6 should be pursued in this cancer.

Case report: an atypical peripapillary uveal melanoma.

BACKGROUND: The treatment of uveal melanoma has seen a shift towards eye conserving treatments. Efforts have been made towards the identification of patients at high risk of metastatic disease with the use of prognostic fine needle biopsy, Monosomy 3 a risk factor for metastatic death thought to occur early in the development of uveal melanoma. CASE PRESENTATION: We report a case in which an atypical optic nerve lesion was found to be a peripapillary primary uveal melanoma with distinct non-pigmented and pigmented halves on gross dissection and corresponding disomy 3 and monosomy 3 halves. The tumour demonstrated rapid growth with apparent transformation from disomy 3 to monosomy 3. CONCLUSIONS: These are clinical features that challenge the current concepts of the cytogenetic pathogenesis of uveal melanoma and demonstrate the potential problems and limitations of prognostic fine needle biopsy and molecular classifications.

Comprehensive clinical imaging, histopathological analysis and liquid biopsy-based surveillance of human uveal melanoma in a prolonged rabbit xenograft model.

Uveal melanoma is the most common intraocular tumor in adults. Our group has previously developed a human uveal melanoma animal model; however, adverse effects caused by the immunosuppressive agent, cyclosporine A, prevented animals from surviving more than 12 weeks. In this study, we tested multiple cyclosporine A doses over an extended disease course up to 20 weeks, providing complete clinical imaging of intraocular tumors, histopathological analysis and liquid biopsy biomarker analysis. Twenty albino rabbits were divided into four groups with different daily cyclosporine A schedules (0-10 mg/kg) and inoculated with human uveal melanoma cell lines, 92.1 or MP41, into the suprachoroidal space. Rabbits were monitored with fundoscopy, ultrasound and optical coherence tomography. Intraocular tumors (macroscopic or microscopic) were detected in all study animals. Tumor size and growth were correlated to cyclosporine A dose, with tumors regressing when cyclosporine A was arrested. All tumors expressed HMB-45 and MelanA; however, tumor size, pigmentation and cell morphology differed in 92.1 vs. MP41 tumors. Finally, across all groups, circulating tumor DNA from plasma and aqueous humor was detected earlier than tumor detection by imaging and correlated to tumor growth. In conclusion, using three clinically relevant imaging modalities (fundoscopy, ultrasonography and optical coherence tomography) and liquid biopsy, we were successfully able to monitor tumor progression in our rabbit xenograft model of human uveal melanoma.

Expression of SIRT1 in choroidal neovascular membranes.

PURPOSE: SIRT1 is a deacetylase that has been shown to be instrumental in embryonic and pathologic vascular formation. The purpose of this study was to evaluate the potential role of SIRT1 in the pathogenesis of choroidal neovascularization in age-related macular degeneration. METHODS: The expression of SIRT1 was assessed via immunohistochemistry in nine excised human choroidal neovascularization membranes and seven non-age-related macular degeneration donor eyes. Enzyme-linked immunosorbent assay-based angiogenesis arrays were used to assess the potential of an SIRT1 inhibitor, nicotinamide, to reduce secretion of 10 unique proangiogenic cytokines from retinal pigment epithelial cells. RESULTS: SIRT1 was expressed more frequently in choroidal neovascularization membranes than donor eyes about vascular endothelial cells (78 vs. 29% positive cases) and retinal pigment epithelial cells (57 vs. 14% positive cases). SIRT1 inhibition in retinal pigment epithelial cells correlated with significantly decreased secretion of three potent proangiogenic cytokines: angiogenin, platelet-derived growth factor BB, and vascular endothelial growth factor A. CONCLUSION: SIRT1 levels appear elevated in human choroidal neovascularization membranes compared with control eyes. Moreover, inhibition of SIRT1 activity is correlated with decreased secretion of potent proangiogenic cytokines. Collectively, these data support a potential role for SIRT1 in the pathogenesis of neovascular age-related macular degeneration.

Aberrant nuclear repressor coreceptor 1 localization in human retinoblastoma.

BACKGROUND/AIMS: Nuclear receptor corepressor 1 (NCoR1) is a protein complex with diverse functions in development and tumorigenesis. We investigated the pattern of expression and histopathological correlation of NCoR1 in 41 retinoblastoma tumor samples, 1 retinoblastoma cell line (WERI-Rb-1) and human retinal progenitor cells (hRPCs). METHODS: Tissue sections from 41 retinoblastoma cases, the retinoblastoma cell line WERI-Rb-1 and hRPCs were stained with rabbit polyclonal anti-NCoR1 H76 antibody. Percentage and intensity of staining were classified by an ocular pathologist from 0 to 3. The paired t test was used to test for differences. RESULTS: In the nonneoplastic retina, NCoR1 was expressed mainly in cell nuclei. The retinoblastoma tumor cells similarly had nuclear NCoR1 but also had a higher level of cytoplasmic NCoR1 expression compared to all 3 normal retinal cell layers (p < 0.002). In contrast to the normal retina, NCoR1 was mainly expressed in the cytoplasm of the proliferating WERI-Rb-1 cells. This cytoplasmic expression pattern was also seen in the undifferentiated hRPCs. CONCLUSIONS: The aberrant cytoplasmic expression of NCoR1 in retinoblastoma appears to be associated with the proliferative and/or dedifferentiated properties of retinoblastoma. Further investigation into the role of NCoR1 in retinoblastoma may provide insight into how therapeutically inhibiting its nucleocytoplasmic shuttling may affect retinoblastoma tumor biology.

Clinical and anatomic correlates of objectively measured zonular dehiscence in 427 postmortem pseudophakic eyes.

OBJECTIVE: This study aims to objectively measure the degree of zonular dehiscence in postmortem eyes and to assess for clinical and anatomic correlates. DESIGN: Cross-sectional study. MATERIALS: Four hundred and twenty-seven postmortem pseudophakic human eyes. METHODS: Eyes were obtained from the Lions Gift of Sight Eye Bank. Microscope photographs were taken of the eyes in Miyake-Apple view, and region-of-interest analysis was performed using ImageJ to measure the area, circumference, and diameter of the capsular bag, the ciliary ring, and the capsulorhexis. Clinical and anatomic parameters were assessed using simple linear regression analysis and one-way analysis of variance with post hoc Bonferroni testing. Zonular dehiscence was measured via 2 surrogates: capsule area over ciliary ring area ratio (CCR) and capsule-ciliary ring decentration (CCD). Low CCR and high CCD indicate more zonular dehiscence. RESULTS: CCR was significantly inversely correlated with smaller capsulorhexi (p = 0.012), lower intraocular lens power (p < 0.00001), younger age at death (p = 0.00002), and a longer cataract-to-death time (p = 0.00786). CCR also was significantly lower in glaucomatous cases (p = 0.0291). CCD was significantly correlated with longer cataract-to-death time (p = 0.000864), larger ciliary ring area (p = 0.001), more posterior capsule opacification (p = 0.0234), and higher Soemmering's ring opacity (p = 0.0003). There was also significantly more decentration in male eyes than in female eyes (p = 0.00852). CONCLUSIONS: CCR and CCD are novel measures of zonular dehiscence in postmortem eyes, with many interesting correlates. An enlarged ciliary ring area is possibly associated with zonular dehiscence in pseudophakic eyes and may be a quantifiable surrogate in vivo.

Postmortem Ultrastructural Analysis of the Retina from COVID-19 Deceased Patients.

PURPOSE: COVID-19 (coronavirus disease 2019) is an infectious disease caused by SARS-CoV-2, first reported in 2019 in Wuhan, China. Among the common complications is a pro-inflammatory and hypercoagulative response that compromises the vasculature among various organs. METHODS: In this report, we present the postmortem retinal findings of five patients observed by means of optical microscopy and transmission and scanning electron microscopy techniques. RESULTS: Clinical manifestations such as retinal hemorrhages and exacerbated inflammatory infiltrate, altered ultra structure with swollen mitochondria and pyknotic cells in both layers of the retina were observed in all analyzed eyes. CONCLUSION: Our data point to the fragility of this tissue in cases of severe COVID-19.

Analytical solutions and validation of electric field and dielectrophoretic force in a bio-microfluidic channel.

In a microbiological device, cell or particle manipulation and characterization require the use of electric field on different electrodes in several configurations and shapes. To efficiently design microelectrodes within a microfluidic channel for dielectrophoresis focusing, manipulation and characterization of cells, the designer will seek the exact distribution of the electric potential, electric field and hence dielectrophoresis force exerted on the cell within the microdevice. In this paper we describe the approach attaining the analytical solution of the dielectrophoretic force expression within a microchannel with parallel facing same size electrodes present on the two faces of channel substrates, with opposite voltages on the pair electrodes. Simple Fourier series mathematical expressions are derived for electric potential, electric field and dielectric force between two distant finite-size electrodes. Excellent agreement is found by comparing the analytical results calculated using MATLAB™ with numerical ones obtained by Comsol. This analytical result can help the designer to perform simple design parametric analysis. Bio-microdevices are also designed and fabricated to illustrate the theoretical solution results with the experimental data. Experiments with red blood cells show the dielectrophoretic force contour plots of the analytical data matched to the experimental results.