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Biomedical subjects

H H Brown

Publications and source records attributed to H H Brown.

At least 19 recordsLinked to original sources
PubMed2003

Retinal neovascular markers in retinopathy of prematurity: aetiological implications.

AIM: (1) To determine if expression of the blood-tissue barrier associated glucose transporter GLUT1 is preserved by the neovasculature of retinopathy of prematurity (ROP), in contrast with the reported loss of GLUT1 expression in preretinal vessels of proliferative diabetic retinopathy. (2) To compare the vascular immunophenotype of ROP to juvenile haemangioma, another perinatal neovascular disorder that has recently been shown to express placental type vascular antigens, including GLUT1 and Lewis Y antigen. METHODS: A retrospective case report was carried out. Immunoreactivities for GLUT1 and Lewis Y antigen were assessed in a human eye with stage 3 ROP and compared with those in a control (paediatric) eye. The presence or absence of endothelial GLUT1 and Lewis Y immunoreactivity was determined in preretinal and intraretinal vessels. RESULTS: Immunoreactivity was positive for GLUT1 and negative for Lewis Y in the intraretinal and preretinal neovasculature of the ROP affected eye and in the normal retinal vessels of the control eye. CONCLUSIONS: Retention of immunoreactivity for GLUT1 distinguishes ROP from proliferative diabetic retinopathy. Furthermore, absence of Lewis Y antigen co-expression distinguishes ROP from juvenile haemangioma, a perinatal form of GLUT1 positive neovascularisation that has recently been linked to placental vasculature.

Biomarkers↗
PubMed2001

Catastrophic antiphospholipid antibody syndrome manifesting as an orbital ischemic syndrome.

Painful bilateral ophthalmoparesis, marked proptosis, increased intraocular pressure, and blindness developed in a 29-year-old woman with protein C deficiency and catastrophic antiphospholipid syndrome. Magnetic resonance imaging of the orbits showed bilateral proptosis, globe tenting, and tethering of the optic nerves consistent with an orbital ischemic syndrome. Despite aggressive therapy for antiphospholipid syndrome, the patient died. The autopsy showed necrosis of orbital tissues. This is the first report of orbital ischemic syndrome from protein C deficiency and antiphospholipid syndrome.

Adult↗
PubMed1998

Mini radial keratotomy reduces ocular integrity. Axial compression in a postmortem porcine eye model.

OBJECTIVE: This study aimed to examine ocular rupture force in pig eyes after "minimally invasive radial keratotomy" (MRK) and standard radial keratotomy (SRK). DESIGN: Experimental study. MATERIALS: A total of 71 pairs of pig eyes (51 control eyes) were examined. INTERVENTION: An axial-torsional Materials Testing System (MTS, Eden Prairie, MN) was used to apply blunt force to the corneal surface. A force transducer measured the rupture forces in control eyes and in eyes with MRK or SRK. Five groups of paired eyes were compared: 2.0-mm MRK versus control (N = 12), 3.5-mm MRK versus control (N = 21), 6.5-mm SRK versus control (N = 18), SRK versus 3.5-mm MRK versus 2.0-mm MRK (N = 10). MAIN OUTCOME MEASURE: Ocular rupture force (newtons) was measured. RESULTS: The mean rupture force in newtons was 746.3 for control eyes, 514.2 for 2.0-mm MRK, 353.1 for 3.5-mm MRK, and 246.2 for SRK. Analysis of variance showed a statistically significant difference (P < or = 0.04) between paired comparisons. CONCLUSION: The MRK and SRK significantly weakened ocular integrity compared with control eyes not operated on. MRK required significantly more force to rupture than SRK. MRK eyes, however, ruptured at 50% to 70% of the force required to rupture eyes not operated on. Any patient considering radial keratotomy should be counseled about the risk of greater ocular damage in trauma.

Animals↗
PubMed1997

Oculocerebral dysgenesis in the linear nevus sebaceous syndrome.

PURPOSE: The authors document the association of peripapillary staphyloma and an atypical variant of hemimegalencephaly with the linear nevus sebaceous syndrome. BACKGROUND: Linear nevus sebaceous syndrome is an uncommon neurocutaneous disorder that has a propensity to involve the eyes. METHODS: Clinical, histopathologic, and neuroimaging findings are examined in a child with linear nevus sebaceous syndrome. RESULTS: In addition to bilateral peripapillary staphylomas, ophthalmologic abnormalities included a corneal dermoid, a complex conjunctival choristoma, macular hypoplasia, and optic nerve hypoplasia with contralateral optic atrophy. Magnetic resonance imaging disclosed a rare form of hemimegalencephaly characterized by hypoplasia of an optic radiation within the enlarged, dysgenetic cerebral hemisphere. CONCLUSION: The spectrum of oculocerebral dysgenesis in the linear nevus sebaceous syndrome can be expanded to include peripapillary staphyloma and atypical hemimegalencephaly with hypoplasia of an optic radiation.

Brain↗
PubMed1997

Clinical and molecular characterization of a family affected with X-linked ocular albinism (OA1)

Thirty-one members of a family affected with X-linked ocular albinism (OA1) were studied to characterize the clinical phenotype and identify the disease-causing mutation. The family members were examined with ophthalmoscopy, electroretinography, and Goldmann perimetry. Linkage analysis was performed with markers from the OA1 locus. Exons 2 and 8 of the OA1 gene were assayed with the polymerase chain reaction (PCR). The six affected males had visual acuities ranging from 20/40 to 20/200. All had nystagmus, iris transillumination, and foveal hypoplasia. The eldest affected male had 20/40 vision and was asymptomatic. The level of the visual acuity of the affected males was not related to the degree of retinal pigmentation. All seven female carriers had normal visual function but were found to have iris transillumination defects and variable retinal pigmentary appearance ranging from minimal pigmentary disturbance, patchy and diffuse hypopigmentation, to classic 'mud-splattered' appearance. Linkage analysis was consistent with a disease-causing mutation at the OA1 locus. PCR analysis revealed a deletion which includes at least the portion of the OA1 gene between exons 2 and 8. Affected males with X-linked ocular albinism can have a visual disability that ranges from almost none to legal blindness, and the female carriers can have variable retinal pigmentary appearance. Mutation screening of the OA1 gene can be used to confirm the diagnosis in isolated males of some families, and genetic linkage analysis can be used to accurately identify carriers even when the specific mutation cannot be identified.

Adult↗
PubMed1994

Visual loss from idiopathic intracranial pachymeningitis.

We report three patients with chronic headaches and optic neuropathy due to widespread meningeal thickening shown on enhanced MRI; all had biopsy-proven intracranial pachymeningitis (fibrosclerosis of the meninges). Two patients had bilateral optic neuropathy, elevated CSF protein, and polyclonal serum hypergammaglobulinemia. They developed temporal lobe cortical necrosis or sagittal sinus thrombosis, presumably due to compromised dural venous drainage from extensive meningeal fibrosis. The other patient had multiple cranial nerve palsies and unilateral optic neuropathy with normal CSF. Corticosteroid therapy improved visual function in all three patients, although all had persisting visual deficits. Gadolinium-enhanced MRI was essential in identifying meningeal inflammation and locating suitable biopsy sites.

Adult↗
PubMed1991

Ultrastructural and immunohistochemical features of coronal adenomas.

We studied by electron microscopy three coronal adenomas discovered incidentally in eyes removed surgically. Tumor cells displayed prominent intercellular interdigitations with numerous desmosomes, mitochondria, abundant rough endoplasmic reticulum, and nuclei with membrane infoldings and a granular chromatin pattern. In these characteristics, the tumor cells were identical to nonpigmented ciliary epithelium of the ciliary processes. These growths contained abundant extracellular material, which showed a dimorphic pattern of complex reduplicated basal lamina and granular areas without structure. Immunohistochemical studies on formalin-fixed, paraffin-embedded coronal adenomas demonstrated type IV collagen and laminin in the extracellular material. These findings confirm that coronal adenomas develop from nonpigmented ciliary epithelium and that the extracellular material of these tumors contains components normally present in basement membranes.

Adenoma↗
PubMed1991

Lipomatous hamartoma of the orbit.

Proliferations of mature adipose tissue, while common in retroperitoneal and subcutaneous sites, rarely occur in the orbit. We describe the clinical, radiographic, and histopathologic findings of a nonencapsulated lipomatous tissue overgrowth of the right orbit in a 35-year-old man. The mass had caused proptosis since childhood and was apparently present since birth. Due to the age at onset, the histologic similarity to normal orbital fat, and the lack of encapsulation or choristomatous elements, we propose the term lipomatous hamartoma for this entity.

Adult↗
PubMed1991

Supraciliary hemangiopericytoma.

A 10-year-old black girl complaining of pain and decreased vision in the left eye was found to have a smoothly elevated ciliochoroidal mass involving the superonasal quadrant of the left eye. The mass appeared circumscribed and uniformly dense by computed tomography. The tumor was hyperintense to vitreous and cerebral white matter on T1-weighted magnetic resonance imaging but was hypointense to vitreous and hyperintense to white matter on T2-weighted magnetic resonance imaging. Results of gross examination of the enucleated eye showed a sharply circumscribed, tan, intraocular mass arising equatorially. Results of histopathologic examination showed a well-vascularized spindle cell proliferation with a sinusoidal pattern characteristic of hemangiopericytoma. This is the third reported case of intraocular hemangiopericytoma and the first in a pediatric patient.

Child↗
PubMed1990

Orbital intramuscular schwannoma.

In an 8-year-old girl with asymptomatic proptosis, computed tomographic scans showed a large medial orbital mass that contoured the globe anteriorly, bowed the optic nerve laterally, and extended posteriorly to the orbital apex. T1-weighted coronal magnetic resonance images showed the mass to be a diffusely enlarged medial rectus muscle. Histopathologic examination of a medial rectus muscle biopsy specimen disclosed a multinodular, intramuscular schwannoma, separating and infiltrating normal skeletal muscle fibers. The intramuscular location and multinodular configuration of this tumor, together with its occurrence in a child, distinguish it from previous orbital schwannomas.

Biopsy↗
PubMed1990

Primary orbital melanoma associated with orbital melanocytosis.

We report a case of primary orbital melanoma in a 17-year-old girl. The patient presented with painless proptosis during the first trimester of pregnancy. Computed tomography demonstrated a well-circumscribed mass located infra-temporally in the right orbit. The tumor was bluish-black, grossly encapsulated, and associated with orbital blue nevi. Histologic examination of the mass revealed a pigmented spindle-cell neoplasm. On electron microscopy, the presence of premelanosomes and the absence of basal lamina supported the diagnosis of melanoma. Malignant transformation of a preexisting nevus is postulated since perineural foci of benign dendritic melanocytes were seen within the melanoma. There has been no recurrence or metastasis in a 2-year follow-up. Of 30 primary orbital melanomas reviewed, 12 (40%) were associated with periorbital pigmentary disorders, such as oculodermal melanocytosis, blue nevus, and ocular melanocytosis. Our case is unique since the pigmentary lesions were limited to the orbital tissues.

Adolescent↗
PubMed1989

Keratinizing corneal intraepithelial neoplasia.

Corneal intraepithelial neoplasia (CIN) is the term applied by some authors to the spectrum of disease ranging from mild dysplasia to carcinoma in situ. Such lesions usually are associated with dysplastic or neoplastic processes at the limbus or adjacent conjunctiva; isolated corneal dysplasia is rare. Clinically, CIN appears as a geographic, gray, translucent thickening of the epithelium with fimbriated or scalloped borders and lesions often contain scattered white dots. We report a case of intraepithelial neoplasia limited to the cornea that had the unusual clinical appearance of a white plaque, which prompted the misdiagnosis of a calcific scar. Histopathologic examination of the debrided tissue revealed intraepithelial neoplasia and marked hyperkeratosis as the cause of the opacification.

Corneal Diseases↗
PubMed1988

Traumatic dehiscence of incisions seven years after radial keratotomy.

We studied the clinical and pathologic features of a traumatically ruptured eye seven years after radial keratotomy. The radial keratotomy incisions were identified and topographically related to perforation sites. Three radial keratotomy incisions were perforated. Seven additional incisions were partially separated. Radial keratotomy incision depths ranged from 50% to 90% in the remaining incisions. All incisions showed disruption of Bowman's membrane, 15 of 16 showed malapposition of Bowman's membrane, and 14 of 16 showed epithelial plugging. In this case the healing and strength of radial keratotomy incisions were suboptimal seven years after the procedure.

Eye Injuries↗
PubMed1988

Mycobacterium fortuitum keratitis.

Two of four cases of Mycobacterium fortuitum keratitis occurred after corneal surgery with contact lens wear, one was associated with extended contact lens wear alone, and one occurred after a foreign body injury. All cases were characterized by pain, conjunctival hyperemia, stromal inflammation, and ulceration. Diagnosis was made by culture and acid-fast staining of corneal scrapings. On the basis of published experience with amikacin for the treatment of nonocular M. fortuitum infections, three patients were treated with topical amikacin. Two patients responded clinically, but histopathologic examination of a penetrating keratoplasty specimen in one of the two disclosed persistent infection. One patient was cured of early disease by debridement alone. Rapid diagnosis and absence of corticosteroid use were the two most important determinants of successful therapy. In advanced cases, infection may be cured and useful vision restored by penetrating keratoplasty.

Adult↗