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result(s) for
"Mohamed, Yasser Helmy"
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Comparison of rabbit corneal changes during different preservation techniques using optisol-GS and airlift
2023
A previous study suggested that the airlift condition is superior to the Optisol-GS condition for preserving the limbal tissue of the human cornea. The purpose of this research is to investigate a new preservation device that preserves the cornea while separating epithelial and endothelial areas. The differences after preserving the corneal epithelium under different conditions were compared. A total of 24 corneas of New Zealand rabbits were divided into four groups in which the corneal epithelia were submersed in Optisol-GS or under airlift conditions for 1 and 2 weeks at 4
∘
C. Transparency, optical coherence tomography (OCT), hematoxylin and eosin (H &E) staining, and epithelial migration tests were used to assess corneal status. The epithelial migration examination showed significantly greater migration ability after the airlift condition. Corneas in the 1-week Optisol-GS group were the most transparent, followed by the 1-week airlift group. OCT showed a progressive increase in corneal thickness to the end of the study. H &E staining showed that the epithelial cells retained intact cellular structure and morphology of the cells for both 1-week-preserved groups. However, there was disruption of the corneal epithelial cell structure for both 2-week-preserved groups. Corneal epithelium preserved under the hypothermic airlift condition was comparable to that under the Optisol-GS condition.
Journal Article
Effectiveness of a photoscreener in identifying undiagnosed unilateral amblyopia at vision screening of 3-year-old children in Japan
by
Uematsu, Masafumi
,
Mohamed, Yasser Helmy
,
Nakashima, Yumiko
in
Acuity
,
Amblyopia - diagnosis
,
Amblyopia - epidemiology
2022
Purpose
In Japan a basic preparatory ophthalmic examination is routinely performed for 3-year-old children. This study aimed to determine the value of incorporating a photoscreener into the examination and evaluate parents’ satisfaction with the photoscreener examination.
Study design
Prospective study.
Methods
Children aged 42–47 months in Nagasaki City, Japan, underwent a visual acuity test by a parent at home and by automated vision screening using a photoscreener at their local municipal health center between October 2018 and March 2019. Subjects were children referred to Nagasaki University Hospital for examination after failing either test. Children previously diagnosed with strabismus and/or amblyopia were excluded. A questionnaire survey evaluated the level of satisfaction with the photoscreener-based screening by parents who attended these examinations at the local municipal health center.
Results
Of children who completed the two tests, 52 (failed visual acuity test, 3; failed photoscreener examination, 49) were referred for examination. Of the 49 photoscreener failures, 12 were diagnosed with amblyopia: unilateral amblyopia with anisometropic hyperopia in 10 (83.3%), and bilateral amblyopia with astigmatism and hyperopia in 2 (16.7%). The photoscreener detected all 12 cases of amblyopia, whereas the home-based visual acuity test detected only two cases. More than 80% of 1035 parents were satisfied with the photoscreener examination.
Conclusion
Unilateral amblyopia with anisometropic hyperopia was easily overlooked with the home-based test but was detectable by photoscreener examination. The photoscreener proved to be an effective screening tool for amblyopia in children and was considered a satisfactory examination by a high proportion of parents.
Journal Article
Visual outcomes and prognostic factors in open-globe injuries
by
Mohamed, Yasser Helmy
,
Uematsu, Masafumi
,
Tsuiki, Eiko
in
Acuity
,
Care and treatment
,
Classification
2018
Background
Ocular trauma is an important cause of visual loss worldwide. Improvements in our knowledge of the pathophysiology and management of ocular trauma during the past 30 years, in conjunction with advances in the instrumentation and techniques of ocular surgery, have improved the efficacy of vitreoretinal surgery in injured eyes. The aim of the current study was to determine the visual outcomes and prognostic factors of open-globe injuries in the Japanese population.
Methods
Retrospective study of 59 eyes of 59 patients presented with open globe injuries between September 2008 and March 2014 at Nagasaki University Hospital was conducted.
Demographic factors including age, gender, and clinical data such as cause of injury, presenting visual acuity (VA), location of injury, type of injury, lens status, presence of intraocular foreign body, types of required surgeries, and final VA were recorded. According to the classification of Ocular Trauma Classification Group, wound location was classified into three zones. Chi-square test was used to compare presented data.
Results
Out of the 59 patients, 46 were placed in the Light Perception (LP) group, and 13 were placed in the No Light Perception (NLP) group. Work-related trauma was the most common cause (27 eyes) followed by falls (19eyes). Work-related trauma was common in males (
P
= 0.004), while falls was significantly common in females (
P
= 0.00001). Zone III injuries had statistically significantly poor prognostic factor compared to other zones (
P
= 0.04). All cases of NLP group (100%) presented with rupture globe. Poor VA at first visit (
P
= 0.00001), rupture globe (
P
= 0.026), history of penetrating keratoplasty (PK) (
P
= 0.017), retinal detachment (RD) (
P
= 0.0001), vitreous hemorrhage (VH) (
P
= 0.044), and dislocation of crystalline lens (
P
= 0.0003) were considered as poor prognostic factors.
Conclusion
Poor VA at first visit, rupture globe, zone III injuries, history of penetrating keratoplasty, RD, VH, and dislocation of crystalline lens were found to be poor prognostic factors. PPV had a good prognostic value in open globe injuries associated with posterior segment involvement.
Journal Article
Oral kallidinogenase improved visual acuity and maintained chorioretinal blood flow levels after treatment for diabetic macular edema
by
Tsuiki, Eiko
,
Mohamed, Yasser Helmy
,
Suzuma, Kiyoshi
in
Blood flow
,
Care and treatment
,
Diabetes
2018
This study was designed to investigate the therapeutic effects of oral kallidinogenase medication as an adjuvant therapy in treating patients with diabetic macular edema (DME).
This was a prospective, open-labeled, randomized study.
All patients were given posterior sub-Tenon triamcinolone acetonide (STTA) injection and focal laser treatment session for DME. The patients were subdivided into two groups: 1) those treated with oral kallidinogenase for at least 6 months after local treatment (treated group) and 2) those treated without oral kallidinogenase (untreated group). In this study, best-corrected visual acuity (BCVA), central retinal thickness (CRT), subfoveal choroidal thickness (SCT), and chorioretinal blood flow level were measured in 17 patients (19 eyes). Chorioretinal blood flow levels at the disc and macula were measured by laser speckle flowgraphy and evaluated using the mean blur rate (MBR). These data were measured at baseline and at 1, 3, and 6 months after treatment initiation.
BCVA at 6 months after treatment significantly improved in treated group (
<0.05). But the mean CRT after treatment significantly decreased in both groups. There was no significant difference in the mean SCT at baseline between the two groups. The mean SCT after treatment in treated group was significantly thinner than that before treatment (
<0.05). Compared to baseline (100%), MBR at the disc and the macula at 6 months after treatment significantly decreased to 84.8% and 86.2%, respectively, in untreated group (
<0.05), though it remained unchanged at 98.7% and 99.7% in treated group.
Oral kallidinogenase medication is useful as an adjuvant therapy to enhance the therapeutic effect of STTA in DME patients.
Journal Article
The protective effects of chitosan and curcumin nanoparticles against the hydroxyapatite nanoparticles-induced neurotoxicity in rats
by
Aboudeya, Hebatallah Mohammed
,
Kamel, Maher A.
,
Mahmoud, Shimaa A.
in
631/378
,
631/443
,
631/45
2024
Hydroxyapatite nanoparticles (HANPs) have extensive applications in biomedicine and tissue engineering. However, little information is known about their toxicity. Here, we aim to investigate the possible neurotoxicity of HANPs and the possible protective role of chitosan nanoparticles (CNPs) and curcumin nanoparticles (CUNPs) against this toxicity. In our study, HANPs significantly reduced the levels of neurotransmitters, including acetylcholine (Ach), dopamine (DA), serotonin (SER), epinephrine (EPI), and norepinephrine (NOR). HANPs significantly suppressed cortical expression of the genes controlling mitochondrial biogenesis such as peroxisome proliferator activator receptor gamma coactivator 1α (PGC-1α) and mitochondrial transcription factor A (mTFA). Our findings revealed significant neuroinflammation associated with elevated apoptosis, lipid peroxidation, oxidative DNA damage and nitric oxide levels with significant decline in the antioxidant enzymes activities and glutathione (GSH) levels in HANPs-exposed rats. Meanwhile, co-supplementation of HANP-rats with CNPs and/or CUNPs significantly showed improvement in levels of neurotransmitters, mitochondrial biogenesis, oxidative stress, DNA damage, and neuroinflammation. The co-supplementation with both CNPs and CUNPs was more effective to ameliorate HANPs-induced neurotoxicity than each one alone. So, CNPs and CUNPs could be promising protective agents for prevention of HANPs-induced neurotoxicity.
Journal Article
Microsporidial keratoconjunctivitis – first outbreak in Japan
by
Diya Tang
,
Masafumi Uematsu
,
Yasser Helmy Mohamed
in
Adult
,
Anterior segment optical coherence tomography (AS-OCT)
,
Antibiotics
2023
Background
Most cases of microsporidial keratoconjunctivitis are found in the Southern hemisphere. Our purpose was to investigate the first outbreak of microsporidial keratoconjunctivitis in Japan among healthy, immunocompetent soccer players from the same team during a 1-month period.
Case presentation
This study is an observational case series. The medical records were analyzed for five cases with microsporidial keratoconjunctivitis who presented within September 2022. All five cases were males between 28 and 36 years old. These previously healthy individuals belonged to the same football team. Their eyes were considered susceptible to contaminated water or dirt from the turf at game and practice sites. All cases involved unilateral conjunctivitis, with scattered round white lesions that showed positive fluorescein staining in the corneal epithelium. All cases experienced diminution of vision in the affected eye. In three cases, direct smears showed spores of approximately 2–3 μm in diameter. Polymerase chain reaction (PCR) analysis of corneal scrapes revealed partial amplification of microsporidial 18 S ribosomal RNA gene in four cases. Sequences of PCR products from all four cases showed 100% identity with strains of
Vittaforma corneae
previously reported from an outbreak in Singapore. All cases were treated with topical therapy, including voriconazole, fluorometholone, and levofloxacin. Four eyes underwent corneal scraping. After treatment, all eyes healed without residual opacities.
Conclusions
Only a few sporadic case reports of this disease have previously been reported in Japan. We detected
V. corneae
in our case series, representing what appears to be the first outbreak of microsporidial keratoconjunctivitis in Japan. Exposure to contaminated water or soil, in addition to inadequate sanitary facilities, represents a potential source of infection. Further investigations to clarify the characteristics of microsporidia seem warranted.
Journal Article
Is it really descemetocele? Morphology of extremely thin membrane that remained after severe corneal melting: a case report
by
Mohamed, Yasser Helmy
,
Uematsu, Masafumi
,
Nishida, Teruo
in
Adherens junctions
,
Aged
,
Anatomy
2025
The aim of this study was to report transmission electron microscopic findings of a case with whole corneal descemetocele following infective corneal ulcer for the first time in literature. A 72-year-old male patient presented with infective corneal ulcer. After resolution of the infection, corneoscleral transplantation was performed. The excised very thin corneal membrane was processed for transmission electron microscopic examination. Transmission electron microscopic examination of the specimen revealed many layered structures that consisted of two different types of cells. The first type consisted of lighter staining polygonal cells, while the second consisted of elongated cells with relatively dense staining. All cells were connected with a large number of gap or adherens junctions with intercalation of the cell membranes of adjacent cells. A haphazard distribution of cytoplasmic microfilaments were also observed in all of the cell types. There was no evidence of the presence of endothelial cells throughout the specimen. There was also no evidence of Descemet membrane presence except for a small part adjacent to iris tissue that contained some melanosomes. Although we clinically diagnosed descemetocele, Descemet membrane was not present at the electron microscopic level, and thus, the expression “descemetocele” is inappropriate.
Journal Article
Healed Perforated Corneal Ulcers in Human
2025
This study investigates the pathophysiological process of healed perforated corneal ulcers (HPCUs) in humans. All subjects underwent keratoplasty due to opacities or leakage from HPCUs. Half of each specimen was fixed with 4% glutaraldehyde for transmission electron microscope (TEM) examination. The other half was fixed in 10% formaldehyde for immunofluorescence (IF) examination. TEM identified layered structures with two cell types (polygonal and elongated) connected by gap or adherent junctions during early stage of healing. Both apoptotic and mitotic changes were found in both types of cells. There were no endothelial cells or Descemet’s membrane (DM) present in early stage of healing. During the intermediate stage, the healed area comprised three layers: epithelium, Bowman’s layer, and stroma, with an increase in stromal collagen. Later, adjacent endothelial cells crept in, forming DM and completing the cornea’s 5-layer structure. IF examinations revealed that vimentin+ and α-smooth muscle actin (αSMA)+ myofibroblasts gathered around the damaged site. Proliferating cell nuclear antigen+ cells, which indicated cell proliferation, were found in both cells. Anti-phospho-histone H2AX antibodies were found in some epithelial cells. CK14-positive cells were only found in superficial polygonal cells. Corneal wound healing is a complex process that includes apoptosis, cell migration, mitosis, differentiation, and extracellular matrix remodeling.
Journal Article
Bilateral Fuchs’ Superficial Marginal Keratitis Diagnosis and Treatment
by
Mohamed, Yasser Helmy
,
Uematsu, Masafumi
,
Kusano, Mao
in
Abnormalities
,
Acuity
,
Amniotic membrane
2024
In this study, we reported two patients with clinical pictures compatible with the diagnosis of bilateral Fuchs’ superficial marginal keratitis (FSMK) treated with surgical treatment and anti-inflammatory drugs. The cases suffered from bilateral photophopia, blurred vision, and pseudopterygium with normal intraocular pressure (IOP). Pseudopterygia extended from temporal and nasal sides and had a gray line between the corneal normal epithelium with no lipid deposits. The first case had a bilateral high mixed astigmatic error and the second had dry eye symptoms. No abnormalities, including systemic inflammatory disease, were found in the laboratory investigations. The first case had bilateral pseudopterygium excision, mitomycin C (MMC) application, and pedicled conjunctival flap transplantation. The patient was followed regularly, and her condition was stable without any recurrence or deterioration in the ocular findings. The second case had conjunctival resection + amniotic membrane transplantation + MMC application six times on the right eye and three times on the left eye during 4 years and suffered recurrences after each operation. Her visual acuity severely decreased with the elevated IOP of both eyes. The patient refused to do any further surgical intervention. Despite its rarity, FSMK should be considered when peripheral corneal infiltration, corneal thinning, and pseudopterygia are observed in both eyes.
Journal Article