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Biomedical subjects

R L Font

Publications and source records attributed to R L Font.

At least 73 records · Page 4Linked to original sources
PubMed1993

Practical applications of some antibodies labelling the human retina.

Eight enucleated eyes were promptly fixed in 10% formalin and processed for light microscopy. Employing the ABC technique, we used antibodies against neuron-specific enolase (NSE), synaptophysin (SY), neurofilament (NF), glial fibrillary acidic protein (GFAP), keratins, LEU-7 and S-100 protein. Using NSE we found immunoreactivity in all sensory layers except the outer segments of photoreceptors which were nonreactive. SY showed a striking immunoreactivity of the synaptic regions (outer plexiform and inner plexiform layers). NF labelled the axons of the ganglion cells. GFAP stained perivascular glial cells and Müller cells only in areas of peripheral microcystoid degeneration. Keratin was non-reactive in all layers. LEU-7 showed that all layers were moderately reactive while the Müller cell processes and the outer limiting membrane were strongly immunoreactive. S-100 protein stained the perivascular glial cells in the nerve fiber layer. We conclude that NSE and LEU-7 are helpful markers for most layers of the sensory retina; GFAP and LEU-7 clearly outline Müller cells and GFAP immunoreacts with astrocytes; NF is specific for axons and SY labels vividly the synaptic regions.

Adult↗
PubMed1993

Granulomatous reaction to collagen implant: light and electron microscopic observations.

A fifty-three-year-old woman noted bilateral linear confluent papules involving the nasolabial folds following injection of bovine collagen (Zyderm). On light microscopic examination the dermis contained epithelioid granulomas centered around the degenerated bovine collagen. Electron microscopic examination demonstrated the degraded collagen fibers, which could be easily differentiated from the native collagen. The patient's clinical findings, management, and the pathogenetic mechanisms of this entity are reviewed.

Collagen↗
PubMed1992

Nontuberculous mycobacterial keratitis. Report of two cases and review of the literature.

We report two cases of nontuberculous mycobacterial keratitis. To our knowledge, case 1 is the first documented case of Mycobacterium chelonei sclerokeratitis and case 2 is the first report of Mycobacterium flavescens keratitis. A total of 40 cases of nontuberculous mycobacterial keratitis involving at least five different species have been reported previously in the literature. Almost all of these opportunistic infections have occurred following either accidental or surgical ocular trauma, usually associated with the use of local corticosteroids. Encountered infrequently, these organisms can be incorrectly identified as other bacteria, including diphtheroids and Nocardia species. Histopathologic examination and special stains of infected tissues may be helpful in establishing the correct diagnosis. Cultures and sensitivity testing are mandatory in determining appropriate treatment.

Aged↗
PubMed1992

Phakomatous choristoma of the eyelid. Immunohistochemical and electron microscopic observations.

BACKGROUND: A 13-month-old Hispanic boy underwent excision of a congenital inferonasal orbital mass arising from the right lower lid. Results of histopathologic examination of the tumor showed a phakomatous choristoma of the eyelid. An immunohistochemical and electron microscopic study of this rare, benign, congenital tumor of lenticular anlage was performed. METHODS: Immunohistochemistry was performed on 4-microns thick sections from paraffin-embedded tissue. Electron microscopy was performed on thin sections stained with uranyl acetate and lead citrate. FINDINGS: The cuboidal epithelial cells that comprise this choristoma showed strongly positive cytoplasmic staining with S-100 protein and vimentin and focally positive staining with a keratin cocktail (AE1/AE3). Electron microscopy showed the presence of numerous 10-nm whorled cytoplasmic microfilaments within degenerating epithelial cells. CONCLUSION: The immunoreactivity of this tumor to keratin and vimentin are newly described in this detailed clinicopathologic report and, together with its S-100 positivity, support the proposal that this tumor is of lenticular anlage. The authors hypothesize that the intracytoplasmic 10-nm intermediate filaments observed with electron microscopic examination within the epithelial cells that comprise this choristoma represent vimentin as detected by immunohistochemistry.

Choristoma↗
PubMed1992

Malignant lymphoma of the ocular adnexa associated with the benign lymphoepithelial lesion of the parotid glands. Report of two cases.

BACKGROUND: The benign lymphoepithelial lesion of the salivary/lacrimal glands is generally regarded as a lymphoproliferative disorder that may be associated with Sjögren syndrome. Although lymphomatous transformation in patients with Sjögren syndrome is well documented, few reports have appeared describing similar findings in patients with a benign lymphoepithelial lesion. METHODS: The authors report the unusual occurrence of malignant lymphoma involving the ocular adnexa in two patients with a histopathologically documented benign lymphoepithelial lesion of the parotid glands. RESULTS: Both patients developed B-cell lymphomas. The eyelid tumor in case 1 expressed IgM/kappa cell surface markers by flow cytometry, and the orbital/conjunctival masses in case 2 showed neoplastic nodules of B cells that were only immunoreactive to lambda light chains (avidin-biotin complex method). CONCLUSION: To the authors' knowledge, this is the first report of ocular adnexal lymphoma arising in patients with a benign lymphoepithelial lesion of the parotid glands. This report establishes that ocular adnexal lymphoma may arise in a patient with a preexisting benign lymphoepithelial lesion.

Aged↗
PubMed1992

Bilateral retinal and brain tumors in transgenic mice expressing simian virus 40 large T antigen under control of the human interphotoreceptor retinoid-binding protein promoter.

We have previously shown that postnatal expression of the viral oncoprotein SV40 T antigen in rod photoreceptors (transgene MOT1), at a time when retinal cells have withdrawn from the mitotic cycle, leads to photoreceptor cell death (Al-Ubaidi et al., 1992. Proc. Natl. Acad. Sci. USA. 89:1194-1198). To study the effect of the specificity of the promoter, we replaced the mouse opsin promoter in MOT1 by a 1.3-kb promoter fragment of the human IRBP gene which is expressed in both rod and cone photoreceptors during embryonic development. The resulting construct, termed HIT1, was injected into mouse embryos and five transgenic mice lines were established. Mice heterozygous for HIT1 exhibited early bilateral retinal and brain tumors with varying degrees of incidence. Histopathological examination of the brain and eyes of three of the families showed typical primitive neuroectodermal tumors. In some of the bilateral retinal tumors, peculiar rosettes were observed, which were different from the Flexner-Wintersteiner rosettes typically associated with human retinoblastomas. The ocular and cerebral tumors, however, contained Homer-Wright rosettes, and showed varying degrees of immunoreactivity to antibodies against the neuronal specific antigens, synaptophysin and Leu7, but not to antibodies against photoreceptor specific proteins. Taken together, the results indicate that the specificity of the promoter used for T antigen and/or the time of onset of transgene expression determines the fate of photoreceptor cells expressing T antigen.

Animals↗
PubMed1992

Myoepithelioma of the lacrimal gland: report of a case with spindle cell morphology.

The case is described of a 23-year-old female patient presenting with unilateral proptosis, headaches, and transient epiphora. Surgery revealed an encapsulated tumour composed exclusively of spindle-shaped cells within a richly vascularised myxoid stroma. Immunohistochemical staining showed focal positivity for smooth muscle actin, vimentin, and glial fibrillary acidic protein. These combined findings are interpreted as providing evidence of a myoepithelioma, which may be regarded as a monomorphic adenoma consisting solely of myoepithelial cells. To our knowledge this is only the second report of such a tumour in the lacrimal gland.

Actins↗
PubMed1992

[Corneal cyst].

A 76-year old woman developed an intracorneal cyst following uncomplicated cataract surgery. Progressive enlargement led to partial visual loss. Following drainage of the cyst, cytopathologic examination showed epithelial cells. The cyst subsequently reformed and caused acute pupillary block. Repeat drainage and cryotherapy were performed. Vision was limited by corneal edema, and penetrating keratoplasty was performed.

Aged↗
PubMed1992

Visual results and complications following posterior iris-fixated posterior chamber lenses at penetrating keratoplasty.

We retrospectively reviewed the records of 13 patients with pseudophakic bullous keratopathy who had undergone penetrating keratoplasty combined with suturing of a posterior chamber intraocular lens (PC-IOL) with angulated haptics to the posterior iris using the four optic positioning holes. Corneal endothelial decompensation was associated with anterior chamber IOLs in nine cases, with iris-fixated lenses in three cases, and a subluxated PC-IOL in one case. Visual acuity was 20/40 or better in 46%, 20/50 to 20/100 in 31%, and 20/200 or worse in 23%. These visual results are comparable with those reported for other similar surgical series. In four of seven eyes that had preoperative peripheral anterior synechiae (PAS), postoperative extension of at least 2 clock hours occurred; progressive angle-closure glaucoma developed in two of the four. In all four eyes, the extension occurred in the region directly overlying the lens haptics. The angulated haptics of iris-sutured PC-IOLs may predispose to extension of PAS and development of progressive angle-closure glaucoma.

Aged↗
PubMed1992

Concurrent benign teratoid medulloepithelioma and pineoblastoma.

Teratoid medulloepithelioma of the ciliary body is a rare tumor usually occurring in young children. Primary tumors of the pineal gland are also quite rare and have a similar age distribution. We report the case of a 2-year-old girl who had a leukocoria of the right eye. Cataract surgery was performed; however, the patient developed a total retinal detachment refractory to treatment. She eventually developed early changes of phthisis bulbi and underwent an evisceration. Histopathologic examination revealed a benign teratoid medulloepithelioma containing islands of hyaline cartilage and rhabdomyoblasts. During the course of her evaluation, a pineoblastoma was discovered and surgically excised. While the association of pineal tumors with retinoblastomas has been well established, no such association has been reported for medulloepitheliomas. To our knowledge, this is the first recorded case of a benign teratoid medulloepithelioma occurring concurrently with a pineoblastoma.

Brain Neoplasms↗
PubMed1991

Recurrent herpes simplex keratitis with concurrent epithelial and stromal involvement. Immunohistochemical and ultrastructural observations.

A 65-year-old man with recurrent herpetic keratitis underwent corneal transplantation for persistent nonimmunologic graft failure. Histopathologic examination of the corneal button revealed an epithelial dendrite containing Cowdry type A inclusion bodies, moderate stromal edema, and a retrocorneal fibrous membrane. Immunohistochemical studies demonstrated herpes simplex virus antigens in epithelial cells bordering the dendritic defect and in stromal keratocytes. The mean width of corneal epithelium displaying herpes simplex virus-positive epithelial cells on either side of the dendritic defect measured 200 +/- 46 microns. By electron microscopy, herpesvirus particles were identified in epithelial cells lining the dendrite as well as in stromal keratocytes. Infected keratocytes were scattered throughout the stroma but were not observed subjacent to the epithelial dendrite. This study demonstrates that a recurrent epithelial dendrite can be associated with subclinical stromal infection of the graft.

Aged↗
PubMed1991

Large-cell acanthoma of the eyelid. Report of two cases.

We describe two cases of large-cell acanthoma that involved the skin of the upper eyelid. Patient 1 was a 71-year-old white man with a pale, well-demarcated papillomatous plaque of 3 months' duration. Patient 2 was a 62-year-old white man with a sharply demarcated plaque-like thickening of the pretarsal skin involving the eyelid margin of 2 years' duration. In both cases, the histopathologic findings were similar and showed an abrupt transition at the edge of the lesion between the normal epidermis and the acanthotic plaque, which displayed hyperkeratosis, hypergranulosis, and focal parakeratosis. The localized epidermal thickening showed enlarged keratocytes that appeared twice their normal size. To our knowledge, this is the first report of large-cell acanthoma involving the eyelid.

Aged↗
PubMed1991

Idiopathic retinal degeneration in the dog: differential patterns of [3H]uridine incorporation and HIOMT-like immunoreactivity in surviving photoreceptors.

Photoreceptor cell pathology was investigated in an 8-yr-old mixed-breed dog which had displayed visual symptoms of 1 month duration. An electroretinogram detected no light-evoked responses. Light and electron microscopic features showed marked thinning and atrophy of the outer both the tapetal and non-tapetal retina appeared to be involved. In the non-tapetal region, a majority of the rod inner segments were missing, while scattered mitochondria-filled stubby inner segments of cones were readily identified. Inner segments of both rods and cones were observed in the tapetal region. Photoreceptor outer segments were completely absent from the affected retina, and no outer segment debris was observed between the photoreceptor layer and the retinal pigmented epithelium (RPE). Autoradiographic analysis of 3-mm retinal disks from the degenerate retina following incubation with [3H]uridine indicated that only 61% +/- 13 S.D. of the remaining nuclei of rod photoreceptors were undergoing RNA synthesis, whereas more than 99% of cone nuclei incorporated the label. Normal and degenerate retina were also analysed for localization of hydroxyindole-O-methyltransferase (HIOMT)-like immunoreactivity. While the normal retina showed immunoreactivity in both rod and cone photoreceptors with more intense immunoreactivity present in cones, the degenerate retina showed HIOMT-like immunoreactivity only in the remaining cone photoreceptors. The results of this study of idiopathic photoreceptor degeneration of the canine retina suggest that although both photoreceptor types are involved, rods are more severely affected than cones.

Acetylserotonin O-Methyltransferase↗
PubMed1991

Aicardi syndrome. A clinicopathologic case report including electron microscopic observations.

Aicardi syndrome is characterized by infantile spasms, agenesis of the corpus callosum, severe mental retardation, and a characteristic chorioretinopathy with lacunar defects. The authors report on a 2-year-old girl with congenital hydrocephaly who was found unresponsive by the baby-sitter and died shortly thereafter. At autopsy, the histopathologic findings, which were confined to the brain and eyes, were found highly characteristic of AIC. The main abnormalities included agenesis of the corpus callosum, micropolygyria, bilateral papillomas of choroid plexi, bilateral microphthalmia, bilateral hypoplasia of the optic nerves, bilateral colobomas of the juxtapapillaris choroid and optic disc, bilateral total retinal detachment with dysplastic rosettes and chorioretinal lacunae with focal thinning, and atrophy of the retinal pigment epithelium and choroid. A detailed histopathologic study of the ocular findings and the brain anomalies is presented. The results of scanning electron microscopy of the chorioretinal lacunae demonstrated peculiar papillary proliferations of the retinal pigment epithelium in both eyes.

Agenesis of Corpus Callosum↗
PubMed1991

Complex choristoma of the eyelid containing ectopic cilia and lacrimal gland.

A 2-year-old girl was born with an aggregate of ectopic cilia in the right upper eyelid that intermittently produced tears. During elective excision, the cilia were found to be clustered tightly with prominent bulb-like follicles. A separate lobe of lacrimal gland tissue was adjacent to the roots of the cilia just posterior to the orbital septum with no direct communication with the lacrimal gland. Histopathologically, the lesion contained multiple large hair follicles in the dermis with accompanying adnexal structures. Large ectopic lobules of lacrimal gland tissue also were present. Postoperatively, the child had a good cosmetic result and has remained asymptomatic over an 18-month follow-up period. To our knowledge, this is the first reported case of an eyelid choristoma containing ectopic cilia and lacrimal gland. Ectopic cilia alone is a very rare anomaly of the lashes, with only nine cases reported in the literature.

Child, Preschool↗
PubMed1991

Primary ocular malignant lymphoma associated with the acquired immune deficiency syndrome.

A 42-year-old man who was human immunodeficiency virus (HIV)-positive complained of floaters in his right eye, which had existed for 1 week, followed by loss of central vision. Results of ophthalmoscopic examination disclosed confluent yellowish-white retinochoroidal infiltrates with perivascular sheathing, which were more prominent superiorly in the right eye. Approximately 10 small, white, intraretinal and choroidal lesions were observed in the nasal periphery of the left eye. Results of cytologic examination of the vitreous of the right eye showed neoplastic cells characteristic of large cell type malignant lymphoma. Shortly thereafter, cytologic examination of the cerebrospinal fluid also showed large cell malignant lymphoma. Magnetic resonance imaging (MRI) showed a mass involving the left cerebellar hemisphere. After bilateral whole-eye radiation therapy, there was complete resolution of the lymphomatous retinochoroidal infiltrates in both eyes. The ophthalmologic and neurologic manifestations of acquired immune deficiency syndrome (AIDS) are discussed. The authors believe this is the first report of ocular malignant lymphoma occurring in a patient with AIDS.

Acquired Immunodeficiency Syndrome↗