Biomedical subjects
E Zamir
Publications and source records attributed to E Zamir.
Laser pointer maculopathy.
PURPOSE: To report a case of macular damage from a laser pointer. METHOD: Case report. A 19-year-old woman had an acute reduction of visual acuity in the right eye after deliberately staring into a commercial class 2 laser pointer for approximately 10 seconds. RESULTS: The patient's best-corrected visual acuity was RE: 20/40, and she had two small pericentral scotomata, as well as a hypopigmented ring-shaped lesion in the fovea. Within 8 weeks, her visual acuity improved to 20/20 and visual field returned to normal, but a subjective relative decrease in brightness of objects viewed by the right eye was apparent. Retinal pigment epithelial abnormality persisted. CONCLUSIONS: Commercial laser pointers, commonly used for teaching and entertainment purposes, may cause notable macular damage if abused. Morphologically, this may manifest as foveal retinal pigment epithelial disturbance.
Neurotrophic corneal endothelial failure complicating acute Horner syndrome.
PURPOSE: The authors report the clinical findings of a unique case of rapid corneal endothelial decompensation in association with acute Horner syndrome. STUDY DESIGN: Case report and literature review. METHODS: The authors followed a 38-year-old woman who developed Horner syndrome after right jugular vein catheterization during cardiac valvular surgery. Shortly after the operation, Horner syndrome accompanied by conjunctival hyperemia and stromal corneal edema developed in the right eye. Over the course of 4 months, the eye became painful, the corneal endothelial cell count dropped precipitously, and the stromal edema worsened, causing a difference of 100 microm in central corneal thickness compared to the unaffected eye. Deep stromal vascularization started at the limbus, resembling interstitial keratitis. RESULTS: A 3-week course of topical steroid treatment resulted in a dramatic improvement in the stromal corneal edema and regression of the deep stromal vascularization. Ocular and right hemicranial pain subsided shortly thereafter. CONCLUSION: The authors hypothesize that corneal endothelial failure in this unique case may have resulted from traumatic sympathectomy. According to experimental evidence in the reviewed ophthalmologic literature, sympathetic innervation may have a neurotrophic role in the cornea. Corneal pathology similar to the authors' case has been described in hemifacial atrophy (Parry-Robson syndrome), a disorder that is assumed to result from sympathetic denervation and that can be produced in animals by cervical sympathectomy. The authors therefore hypothesize that sympathetic denervation of the cornea may rarely cause endothelial decompensation and corneal edema. To the authors' knowledge, this is the first reported case of corneal endothelial failure in Horner syndrome.
Nitroxide stable radical suppresses autoimmune uveitis in rats.
Free radicals have been implicated in the pathogenesis of experimental autoimmune uveoretinitis (EAU). Nitroxides are stable radicals with a superoxide-dismutase-mimicking activity, which exert an anti-inflammatory effect in various animal models of oxidative damage and inflammation, such as experimental colitis and head trauma. We examined the use of the SOD mimic nitroxide 4-hydroxy-2,2,6,6,-tetramethylpiperidine-1-N-oxyl (TPL) to suppress EAU. Adult male Lewis rats were immunized with 125 microg/rat synthetic human retinal S-Ag, emulsified with Freund's adjuvant. Intravenous pertussis toxin was simultaneously injected. Beginning on Day 6, rats were injected with a daily intraperitoneal dose of 35, 175 or 350 micromol/rat of the nitroxide TPL. Control rats received intraperitoneal normal saline. The animals were examined daily, and on the 19th day the eyes were enucleated. Aqueous protein concentrations and retinal lipid peroxidation product levels (ketodienes and conjugated dienes) were determined. Histological sections were stained and examined microscopically. TPL was found to penetrate the aqueous humor readily. Beginning on day 12, rats developed a severe pan-uveitis. Rats in the treatment group had a lower mean clinical and histological score than that of controls. Levels of aqueous humor protein, retinal conjugated diens and ketodiens were all significantly lower in the treatment group. This effect was more pronounced with the lower TPL concentration. We conclude that TPL reduces clinical, biochemical and histopathological severity of S-Ag induced EAU in Lewis rats. This effect is probably mediated by removal of superoxide radicals, but other mechanisms may also be involved.
Central serous chorioretinopathy in a patient with cryoglobulinaemia.
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A rapidly progressive cataract in a patient with autoimmune hypoparathyroidism and acute liver and renal failure.
Cataract is a well-known complication of hypoparathyroidism, albeit the mechanism is obscure. The progression of cataract is typically slow in patients with idiopathic hypoparathyroidism. We describe a case of an extremely rapid evolution of typical hypocalcemic cataracts in a patient with familial autoimmune hypoparathyroidism during acute idiopathic hepatic and renal failure, while serum calcium and phosphorus were unbalanced. Physicians and ophthalmologists must be aware of cataracts developing rapidly in the setting of such metabolic derangements.
Molecular diversity of cell-matrix adhesions.
In this study we have examined for molecular heterogeneity of cell-matrix adhesions and the involvement of actomyosin contractility in the selective recruitment of different plaque proteins. For this purpose, we have developed a novel microscopic approach for molecular morphometry, based on automatic identification of matrix adhesions, followed by quantitative immunofluorescence and morphometric analysis. Particularly informative was fluorescence ratio imaging, comparing the local labeling intensities of different plaque molecules, including vinculin, paxillin, tensin and phosphotyrosine-containing proteins. Ratio imaging revealed considerable molecular heterogeneity between and within adhesion sites. Most striking were the differences between focal contacts, which are vinculin- and paxillin-rich and contain high levels of phosphotyrosine, and fibrillar adhesions, which are tensin-rich and contain little or no phosphotyrosine. Ratio imaging also revealed considerable variability in the molecular substructure of individual focal contacts, pointing to a non-uniform distribution of phosphotyrosine and the different plaque constituents. Studying the quantitative relationships between the various components of the submembrane plaque indicated that the levels of vinculin, paxillin and phosphotyrosine in adhesion sites are positively correlated with each other and negatively correlated with the levels of tensin. Tyrosine phosphorylation of focal contacts was highly sensitive to cellular contractility, and was diminished within 5 minutes after treatment with the kinase inhibitor H-7, an inhibitor of actomyosin contractility. This was followed by the loss of paxillin and vinculin from the focal adhesions. Tensin-rich fibrillar adhesions were relatively insensitive to H-7 treatment. These findings suggest a role for contractility in the generation of matrix adhesion diversity.
c-Cbl/Sli-1 regulates endocytic sorting and ubiquitination of the epidermal growth factor receptor.
Ligand-induced down-regulation of two growth factor receptors, EGF receptor (ErbB-1) and ErbB-3, correlates with differential ability to recruit c-Cbl, whose invertebrate orthologs are negative regulators of ErbB. We report that ligand-induced degradation of internalized ErbB-1, but not ErbB-3, is mediated by transient mobilization of a minor fraction of c-Cbl into ErbB-1-containing endosomes. This recruitment depends on the receptor's tyrosine kinase activity and an intact carboxy-terminal region. The alternative fate is recycling of internalized ErbBs to the cell surface. Cbl-mediated receptor sorting involves covalent attachment of ubiquitin molecules, and subsequent lysosomal and proteasomal degradation. The oncogenic viral form of Cbl inhibits down-regulation by shunting endocytosed receptors to the recycling pathway. These results reveal an endosomal sorting machinery capable of controlling the fate, and, hence, signaling potency, of growth factor receptors.
Iris crystals in Fuchs' heterochromic iridocyclitis.
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Pseudo-normal osmolal and anion gaps following simultaneous ethanol and methanol ingestion.
Methanol, ethylene glycol, and isopropyl alcohol are associated with acute intoxication. The diagnosis is dependent upon high anion-gap metabolic acidosis, and an osmolal gap between the calculated and the measured osmolality. Normal anion gap has been reported in some cases of concomitant methanol and ethanol ingestion, where the high serum levels of ethanol inhibited the metabolism of methanol by alcohol dehydrogenase. The osmolal gap in these cases was higher than expected for methanol, and served as a constant marker for a metabolic derangement. Herewith, we present a patient who presented with normal osmolal and anion gaps 36 h after ethanol and methanol ingestion, yet progressively developing ocular toxicity. Normal anion and osmolal gaps should not rule out earlier methanol poisoning.
The role of preoperative ultrasonography for patients with dense cataract: a retrospective study of 509 cases.
BACKGROUND AND OBJECTIVE: Ocular ultrasonography is widely used for the evaluation of eyes with opaque ocular media. Although preoperative ultrasonography of the globe has been recommended for patients with dense cataracts, the value of such an examination is currently unknown. The purpose of this study was to evaluate the prevalence and nature of intraocular pathologies detected by preoperative ultrasound examination in patients with dense cataract. PATIENTS AND METHODS: The authors retrospectively studied 509 patients referred for routine ultrasound examination of the globe due to dense cataract. Exclusion criteria included known posterior segment pathology, previous ocular surgery or penetrating trauma, and age of younger than 18 years. All the patients underwent ultrasound examination by B-scan and standardized A-scan. RESULTS: In 19.6% of the patients, a posterior segment pathology was revealed by the ultrasound examination. The most frequently disclosed abnormalities were posterior staphyloma (7.2%), retinal detachment (4.5%), and vitreous hemorrhage (2.5%). One patient with a large choroidal malignant melanoma was identified. The prevalence of posterior segment pathologies was slightly higher in patients with a history of ocular trauma, compared with the nontraumatic cataract group (29.6% versus 19.0%, respectively; P = .1). The prevalence of retinal detachment was increased in the traumatic cataract subgroup (14.8% compared with 3.9%), but this difference did not reach statistical significance. CONCLUSION: Preoperative ultrasound examination for patients with dense cataract can be used to detect pathologies that may influence the surgical strategy and the postoperative visual prognosis.
Central serous retinopathy associated with adrenocorticotrophic hormone therapy. A case report and a hypothesis.
BACKGROUND: Central serous retinopathy (CSR) has been linked by several authors to the therapeutic use of adrenocorticotrophic hormone (ACTH) or corticosteroids or to endogenous ACTH hypersecretion. Various pathogenic mechanisms have been suggested to explain this phenomenon; all relate to the steroids as the causative agents. CASE REPORT: A simultaneous, bilateral central serous retinopathy developed in a woman treated by intramuscular injections of a synthetic ACTH analog for arthritis. The condition resolved 2 months after stopping the use of this drug. DISCUSSION: Many investigators consider CSR to be either a disorder of the retinal pigment epithelium (RPE) ion-pump function or a result of choroidal vascular hyperpermeability. ACTH has a melanotrophic part, melanocyte-stimulating hormone (MSH), that may affect RPE cells, which are melanin-pigmented cells of neuroectoderm origin, and alter their ionic pumping properties. This is supported by evidence in the literature for the effect of MSH on animal RPE cells, as well as on other secreting epithelia. MSH is known to act through increasing intracellular cAMP levels. Based on the current concepts regarding the pathogenesis of CSR, two possible mechanisms for ACTH/MSH-associated CSR are suggested. In the first, MSH increases intracellular cAMP levels in RPE cells, thereby inducing pump dysfunction and a reversal of ionic current direction, leading to subretinal fluid accumulation. An alternative mechanism is based on the known ability of MSH to increase the permeability of blood-aqueous and blood-brain barriers. It is hypothesized that MSH disrupts the outer blood-retinal barrier or causes leakage from choroidal vessels.
Transcription-dependent induction of G1 phase during the zebra fish midblastula transition.
The early development of the zebra fish (Danio rerio) embryo is characterized by a series of rapid and synchronous cell cycles with no detectable transcription. This period is followed by the midblastula transition (MBT), during which the cell cycle gradually lengthens, cell synchrony is lost, and zygotic transcription is initially detected. In this work, we examined the changes in the pattern of the cell cycle during MBT in zebra fish and whether these changes are dependent on the initiation of zygotic transcription. To characterize the pattern of the early zebra fish cell cycles, the embryonic DNA content was determined by flow cytometric analysis. We found that G1 phase is below detection levels during the first 10 cleavages and can be initially detected at the onset of MBT. Inhibition of zygotic transcription, by microinjection of actinomycin D, abolished the appearance of G1 phase at MBT. Premature activation of zygotic transcription, by microinjection of nonspecific DNA, induced G1 phase before the onset of MBT, while coinjection of actinomycin D and nonspecific DNA abolished this early appearance of G1 phase. We therefore suggest that during the early development of the zebra fish embryo, G1 phase appears at the onset of MBT and that the activation of transcription at MBT is essential and sufficient for the G1-phase induction.
[Ocular involvement in cancer therapy].
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Choroidal effusion causing transient myopia after panretinal photocoagulation.
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Bactericidal UV-C lamp misuse.
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Juvenile xanthogranuloma masquerading as pediatric chronic uveitis: a clinicopathologic study.
Juvenile xanthogranuloma (JXG) is a rare, pediatric histiocytic skin disorder that may affect the eye. It can present with protean ocular manifestations, including masquerade uveitis, heterochromia, hyphema, or glaucoma. It very rarely involves the retina and posterior segment; indeed, posterior involvement has been documented histopathologically in only one case. We present the case of a 2-year-old child with ocular JXG presenting as chronic, refractive uveitis, without skin or systemic findings. The blind, painful eye was enucleated and found to harbor a diffuse histiocytic process that involved both the anterior and posterior segments, including the retina and subretinal space. Histological, immunohistochemical, and electron microscopic studies confirmed the diagnosis of JXG. The pathologic classification and differential diagnosis of systemic histiocytic disorders are discussed. Since JXG can present as masquerade pediatric uveitis, this entity should be considered in children with atypical uveitis. In rare instances, JXG may involve the posterior segment and the retina, leading to retinal detachment and blindness.
Bleomycin and cyclophosphamide toxicity simulating metastatic nodules to the lungs in childhood cancer.
Two pediatric oncology patients with Ewing's sarcoma and one with mixed germ cell tumor were treated with drug regimens that included bleomycin or cyclophosphamide. Despite progress to apparently complete remission, all manifested pulmonary nodules on computed tomography during or at the end of treatment. Thoracoscopic biopsy to confirm metastasis revealed instead fibrotic lesions apparently attributable to bleomycin or cyclophosphamide. After cessation of chemotherapy, the pulmonary lesions resolved and all three patients sustained their remissions. The case histories and comments on the diagnosis and management of pulmonary nodules are reviewed.