Role of Schwann Cells in Preservation of Retinal Tissue Through Reduction of Oxidative Stress

The aim of this study was to evaluate the effect of subretinal injection of Schwann cells on preservation of retina by decreasing oxidative stress in Dystrophic Royal College of Surgeons (RCS) rats. Schwann cells were harvested from the sciatic nerve of postnatal day 5, RCS rats. Twenty-five RCS rats randomly assigned to cell and sham groups. Schwann cells injected in the sub-retinal space in one eye of the cell group and carrier medium was injected in one eye of the sham group. The proof for the appropriate site of injection of Schwann cells confirmed by the green fluorescent protein (GFP) positive cells. Electroretinogram (ERG) and enucleation for histopathology and enzymatic evaluation were performed 1, 2 and 3 months post-injection. The enzymatic evaluation included catalase, superoxide dismutase (SOD) and glutathione peroxidase 1 (GPx1) by enzyme-linked immunosorbent assay (ELISA) method. Three months after injection, histopathology assessments showed a complete absence of the outer nuclear layer (ONL), photoreceptors and obvious reduction of retinal pigment epithelium (RPE) in the sham group. Cell group showed marked preservation of RPE, choroidal congestion and mild presence of ONL. The green fluorescent protein positive Schwann cells remained in one integrated layer during the study under RPE. The enzymatic evaluation showed that in cell group expression of SOD and GPx1 until month 2 and catalase until month 1 were significantly more than the sham group. At the end of month 3, the amplitude of ERG waves significantly preserved in cell group in comparison to baseline waves and the sham group. We concluded that Schwan cells are able to preserve retinal in RCS rats by reducing oxidative stress. Epub: October 1, 2019

Epidemiological and Histopathological Assessment of Corneal Dystrophies Leading to Corneal Transplantation

AbstractPurpose: To carry out an epidemiological assessment of corneal dystrophies leading to corneal transplantation and to determine different subtype frequencies. Patients and Methods: In this retrospective study, pathological records of patients who had corneal transplantations other than endothelial keratoplasty between the years 2002 and 2014 were examined. To determine different subtype frequencies when corneal dystrophies led to corneal transplantation the IC3D classification of corneal dystrophies-edition 2 was used. Results: Of the 5867 eyes undergoing corneal transplant surgery during the study timeframe, 239 (4.07%) belonged to patients with corneal dystrophy. The most common age group was between 20 and 29 years (n=57; 23.8%). Macular corneal dystrophy was the most frequent corneal dystrophy subtype (n=117; 49%). Patients with epithelial and sub-epithelial dystrophies were significantly younger, and patients with Fuchs endothelial corneal dystrophy and lattice corneal dystrophy were the oldest age group when undergoing corneal transplantation. Conclusions: Based on our findings Macular corneal dystrophy was the most common corneal dystrophy subtype in patients scheduled for corneal transplantations other than endothelial keratoplasty.   Keywords: Corneal dystrophy; Pathology; Corneal transplantation, Iran

Orbital Dirofilariasis Masquerading As Orbital Rhabdomyosarcoma

Purpose: To report a 12-year-old patient with a rapid growing orbital mass and imaging findings suggestive of rhabdomyosarcoma that was found to be dirofilariasis after mass resection. Case Report: We describe a 12-year-old patient with a rapid growing orbital mass involving medial part of orbit and medial rectus muscle and imaging findings suggestive of rhabdomyosarcoma. Histopathologic examination showed the mass to be composed of granulomatous inflammation and the thread-like object to be Dirofilaria repens. The patient was well post-operation without morbidity. In this paper, we describe distinct clinical features and imaging findings of this interesting case. Conclusion: Deep orbital lesions due to dirofilariasis, as in our case, is extremely rare. It is important to add dirofilariasis to the differential diagnosis of orbital mass lesions. Attention to the imaging clues, as provided in this report, can be helpful

Microbiological Profile of Corneal Ulcers at a Tertiary Referral Center

The aim of this study was to describe patient demographics, microbiological profile, and antibiotic susceptibility of corneal ulcer at a tertiary referral center to improve and optimize diagnosis and treatment of this potentially blinding entity and to reduce antibiotic misuse. Detailed external and slit-lamp bio-microscopic examination of 123 consecutive patients with suspected corneal ulcer was performed at an ophthalmology clinic. Corneal scraping was carried out under slit-lamp bio-microscopy. The obtained material was inoculated on culture media and smeared on a slide for Gram's staining for morphological identification of bacteria and fungus. For samples that developed colony in culture media, antibiotic susceptibility testing was performed. In a significant percentage of patients (72%) neither bacterial agents nor fungi were the cause of corneal ulcer. Of the 34 culture-proven corneal ulcers, in 79% of the cases, bacteria were detected while in 21% of cases, fungi were found. Of the 27 bacterial corneal ulcers, the majority were (67%) caused by Gram-positive bacteria, of which 50% were Streptococcus pneumoniae, and in the Gram-negative bacterial corneal ulcers, most of the cases (44%) were caused by Pseudomonas aeruginosa. In the antibiotic susceptibility report, Streptococcus pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli were resistant to Cotrimoxazole (TS), Streptococcus pneumoniae to Erythromycin (E), Staphylococcus aureus to Peniciline (PG), Pseudomonas aeruginosa to Ceftriaxone (CRO) and Nitrofurantoin (NI), and finally, Escherichia coli to Gentamicin (GM). In conclusion, in a significant number of the patients neither bacterial agents nor fungi were offending microorganisms and bacteria were the most common agent of microbiological corneal ulcer, found in 79% of culture-proven corneal ulcers, followed by fungus, found in 21% of culture-proven corneal ulcers

Subconjunctival Myolipoma Confirmed with Immunohistochemical Analysis: A Case Report

Purpose: To report the clinicopathological features of a rare case of subconjunctival myolipoma and its treatment results.Case Report: A 17-year-old female patient referred to our center with a white-pink mass in her left upper bulbar conjunctiva. The lesion extended to the forniceal conjunctiva. The patient had otherwise normal complete ocular examinations and underwent complete surgical excision of the mass due to cosmetic concerns. The tumor was examined with light–microscopy, following hematoxylin and eosin (H&E), Masson-trichrome, and immunohistochemical (IHC) staining.A definite diagnosis of subconjunctival myolipoma was acheived following the pathological assessment. Six months postoperatively, no tumor recurrence was noted, and ocular examinations were within normal limits

Microbiological Profile of Corneal Ulcers at a Tertiary Referral Center

The aim of this study was to describe patient demographics, microbiological profile, and antibiotic susceptibility of corneal ulcer at a tertiary referral center to improve and optimize diagnosis and treatment of this potentially blinding entity and to reduce antibiotic misuse. Detailed external and slit-lamp bio-microscopic examination of 123 consecutive patients with suspected corneal ulcer was performed at an ophthalmology clinic. Corneal scraping was carried out under slit-lamp bio-microscopy. The obtained material was inoculated on culture media and smeared on a slide for Gram's staining for morphological identification of bacteria and fungus. For samples that developed colony in culture media, antibiotic susceptibility testing was performed. In a significant percentage of patients (72%) neither bacterial agents nor fungi were the cause of corneal ulcer. Of the 34 culture-proven corneal ulcers, in 79% of the cases, bacteria were detected while in 21% of cases, fungi were found. Of the 27 bacterial corneal ulcers, the majority were (67%) caused by Gram-positive bacteria, of which 50% were Streptococcus pneumoniae, and in the Gram-negative bacterial corneal ulcers, most of the cases (44%) were caused by Pseudomonas aeruginosa. In the antibiotic susceptibility report, Streptococcus pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli were resistant to Cotrimoxazole (TS), Streptococcus pneumoniae to Erythromycin (E), Staphylococcus aureus to Peniciline (PG), Pseudomonas aeruginosa to Ceftriaxone (CRO) and Nitrofurantoin (NI), and finally, Escherichia coli to Gentamicin (GM). In conclusion, in a significant number of the patients neither bacterial agents nor fungi were offending microorganisms and bacteria were the most common agent of microbiological corneal ulcer, found in 79% of culture-proven corneal ulcers, followed by fungus, found in 21% of culture-proven corneal ulcers

Isolated Intraconal Meningioma

Purpose: To report a rare case of isolated intraconal meningioma. Case Report: A 24-year-old woman presented with painless proptosis in her left eye which started and progressed during her pregnancy about 10 months ago. Hertel exophthalomometry revealed anterior displacement of the globe with 4 mm of proptosis which was remarkable. Magnetic resonance imaging (MRI) demonstrated an intraconal circumscribed oval-shaped mass with hypointense signals on T1- weighted images and hyperintense signals on T2-weighted images, mimicking cavernous hemangioma. This mass, however, was free of any connections to optic nerve or bones. Due to the imaging characteristics, more prevalent diagnoses like cavernous hemangioma were placed on the top of the differential diagnoses list. However, during the surgical excision, the tumor’s consistency and gross features were not compatible with cavernous hemangioma. The pathologic findings instead determined meningotheliomatous meningioma, a very rare condition, which was far from our expectations prior to the surgery. Conclusion: Ectopic orbital meningiomas are rare tumors that are not easily diagnosed without postoperative histopathology. Despite its low prevalence, they should be considered in the differential diagnosis list of intraconal masses with hypointense signals on T1-weighted images and hyperintense signals on T2- weighted images

Safety of Intravitreal Injection of Stivant, a Biosimilar to Bevacizumab, in Rabbit Eyes

Purpose: To evaluate the safety of intravitreal injection of Stivant, a biosimilar to bevacizumab, in rabbits using electrophysiological and histological analysis. Methods: Both eyes of 41 New Zealand albino rabbits were injected with 0.1 mL (2.5 mg) of Stivant. The rabbits were scheduled to be sacrificed 1, 2, 7, 14, and 28 days after injection for histopathological evaluations. Clinical examinations and electroretinography (ERG) were performed at baseline and just before sacrificing the rabbits. Fourteen separate rabbits received a reference drug (Avastin) and were considered as the control group. Furthermore, three other rabbits received the same volume of saline (saline control group). Rabbits of both control groups were sacrificed four weeks after injection. ERG was performed 1, 2, 7, 14, and 28 days after injections. Results: No significant difference was observed in a- and b-wave amplitudes and latency after intravitreal Stivant injection between baseline and different time points. Moreover, there was no statistically significant difference in wave amplitudes and latency between the Stivant and control groups. The histology of rabbit eyes of the Stivant and control groups after intravitreal injections was not distinguishable. Conclusion: The biosimilar Stivant, up to a dose of 2.5 mg, did not appear to be toxic to the retina in albino rabbits. These results suggest that this drug could be a safe and inexpensive alternative to intravitreal bevacizumab. The efficacy of these injections was not investigated in this study and needs to be evaluated in future studies

Ipsilateral common iliac artery plus femoral artery clamping for inducing sciatic nerve ischemia/reperfusion injury in rats: a reliable and simple method

The aim of this study was to develop a practical model of sciatic ischemia reperfusion (I/R) injury producing serious neurologic deficits and being technically feasible compared with the current time consuming or ineffective models. Thirty rats were divided into 6 groups (n = 5). Animal were anesthetized by using ketamine (50 mg/kg) and xylazine (4 mg/kg). Experimental groups included a sham-operated group and five I/R groups with different reperfusion time intervals (0 h, 3 h, 1 d, 4 d, 7 d). In I/R groups, the right common iliac artery and the right femoral artery were clamped for 3 hrs. Sham-operated animals underwent only laparotomy without induction of ischemia. Just before euthanasia, behavioral scores (based on gait, grasp, paw position, and pinch sensitivity) were obtained and then sciatic nerves were removed for light-microscopy studies (for ischemic fiber degeneration (IFD) and edema). Behavioral score deteriorated among the ischemic groups compared with the control group (p < 0.01), with maximal behavioral deficit occurring at 4 days of reperfusion. Axonal swelling and IFD were found to happen only after 4 and 7 days, respectively. Our observations led to an easy-to-use but strong enough method for inducing and studying I/R injury in peripheral nerves

The Antitumor Effect of Topotecan Loaded Thiolated Chitosan-Dextran Nanoparticles for Intravitreal Chemotherapy: A Xenograft Retinoblastoma Model

Purpose: This research intended to fabricate the thiolated chitosan-dextran nanoparticles (NPs) containing topotecan (TPH-CMD-TCS-NPs) to assess the ability of NPs in improving the efficacy of intravitreal chemotherapy of retinoblastoma in a rabbit xenograft model. Methods: The coacervation process was used to produce the NPs. The cellular uptake of Cyanine-3 (CY3)-labeled NPs were investigated in human retinoblastoma Y79 cells using confocal microscopy. Also, the prepared TPH-CMD-TCS-NPs were tested in vitro by the tetrazolium dyes II (XTT) and flow cytometry in order to assess their cytotoxicity. In addition, a rabbit xenograft model of retinoblastoma was developed to test the antitumor effectiveness of TPH-CMD-TCS-NPs through intravitreal administration. Results: NPs had a mean diameter, polydispersity index, and zeta potential of 30 ± 4 nm, 0.24 ± 0.03 and +10 ± 3 mV, respectively. NPs (IC50s 40.40 compared to 126.20 nM, P = 0.022) were more effective than free topotecan as a dose-based feature. The tumor reaction to intravitreal chemotherapy with NPs was measured by evaluating the percentage of necrosis in the tumor tissue (91 ± 2%) and vitreous seeds (89 ± 9%) through hematoxylin and eosin (H&amp;E) staining. In comparison with the control group, the TPHCMD- TCs-NPs treated group showed a significant decrease in tumor volume seven days after the intravitreal injection (P = 0.039). No significant changes were found in the ERG parameters after the intravitreal injection of TPH-CMD-TCs-NPs or TPH (P &gt; 0.05). Conclusion: This investigation revealed definitive antitumor efficacy of TPH-CMD-TCSNPs by intravitreal administration in the rabbit xenograft retinoblastoma model