The diagnostic histopathologic features of ocular malaria.

BACKGROUND: The ocular complications in patients with malaria have been studied clinically by many investigators, but the histopathologic changes were rarely described and generally regarded as nonspecific. METHODS: The eye of a 53-year-old man who died of chloroquine-resistant Plasmodium falciparum malaria was studied by brightfield and polarized light microscopy. FINDINGS: An epibulbar hemorrhage that involved the conjunctiva, episclera, and tendinous insertion of the medial rectus muscle was present. Cytoadherence and rosetting of the parasitized erythrocytes were observed within the partially occluded lumens of small retinal and uveal blood vessels. The birefringence of hemozoin (malarial pigment) within the lumens of small ocular blood vessels and in the hemorrhagic epibulbar area was demonstrated by polarized light. CONCLUSION: Birefringent hemozoinemia in vascular lumens of ocular tissues indicates systemic malarial infestation by any of the four species of malaria. Cytoadherence and rosetting of the parasitized erythrocytes inside ocular capillaries and venules is diagnostic of P. falciparum and is an important cause of ocular hemorrhage.

A biologic tissue adhesive for vitreoretinal surgery.

Commercially available tissue glue was injected subretinally under mechanically induced retinal detachments in rabbit eyes resulting in chorioretinal adhesions at the injection site. After serial enucleation all eyes underwent histologic evaluation. Results were encouraging, but pooled fibrinogen is not acceptable for human use. A substitute for the pooled fibrinogen fraction, an adhesive using autologous plasma was prepared and studied after subretinal and intravitreal injection into rabbit and pig eyes. Postoperative clinical follow-up was one year for the rabbit eyes and one month for the pig eyes, after which all globes were enucleated. Histopathologic evaluation demonstrated circumscribed chorioretinal adhesions at the injection site. The autologous bioadhesive was applied as an adjunct in vitreoretinal surgery over macular holes and large retinal tears. As it is relatively short acting (ie, 4-6 days), it may be considered as a possible addition to existing techniques, facilitating difficult surgical procedures.

YAG laser treatment of cystoid macular edema.

Fourteen eyes (some aphakic and some with implanted intraocular lenses) underwent neodymium-YAG laser treatment for cystoid macular edema with vitreous incarceration in the corneoscleral wound. Visual acuity improved in all 14 eyes; ten eyes improved at least three Snellen lines and 12 eyes improved at least two Snellen lines. After follow-up periods of one to nine months, 11 eyes had visual acuities of 20/40 or better (only two had had visual acuities of 20/40 preoperatively and none had had a better visual acuity). An additional eye, which had an intraocular lens implant, was treated prophylactically. Visual acuity in this eye remained stable during a nine-month follow-up period. YAG laser treatment produced no adverse side effects or complications in any of the 15 eyes.

Prostacyclin and thromboxane A2 derivatives in rhegmatogenous subretinal fluid.

Aberrations in prostacyclin and thromboxane A2 metabolism have been implicated in a wide spectrum of systemic disease. To our knowledge, derivatives of prostacyclin and thromboxane A2 have not been demonstrated previously in the subretinal fluid of rhegmatogenous detachments. Radioimmunoassays to determine levels of stable derivatives of prostacyclin and thromboxane A2, 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) and thromboxane B2, in rhegmatogenous subretinal fluid samples from ten patients showed the following: 6-keto-PGF1 alpha level, less than 100 to 1,268 pg/mL; thromboxane B2 level, less than 100 to 3,619 pg/mL. The fact that some of these concentrations are higher than the circulating plasma concentrations of 6-keto-PGF1 alpha and thromboxane B2 suggests endogenous ocular production. Our findings establish the presence of prostacyclin and thromboxane A2 derivatives in the rhegmatogenous subretinal fluid.

The YAG laser: an American experience.

We used the OPL3 neodymium-YAG laser to treat 86 patients, 41 male and 45 female, for secondary opacification of an intact posterior capsule one month to four years after planned extracapsular cataract extraction or phacoemulsification, with or without intraocular lens implantation. Visual acuities improved as a function of corneal and macular competence, and careful post-procedure examination revealed no deleterious corneal, iris, vitreal or retinal side effects of the laser treatments. In some of the treated eyes, the implants had single or multiple, small (0.5 mm) white spots on their posterior aspects, or thin linear defects centrally, but in no case was this visually evident to the patient.

Erythrocyte - endothelial cell adherence in sickle cell disease, diabetes mellitus, and falciparum malaria: adverse effects reversed with piracetam.

The erythrocytes of patients with sickle hemoglobin, diabetes, and Falciparum malaria adhere disproportionately to endothelial cells. Such pathophysiological activity compromises the microcirculation and results in clinical disease. Since Piracetam (2-oxo-1 pyrrolidine acetamide) has been shown to have a number of clinically beneficial actions on the formed elements of the blood including disengagement of adherent diabetic and sickle erythrocytes there is a rational basis for the trial of Piracetam as an adjuvant drug in SS disease and in diabetes mellitus to improve function of the microcirculation. For similar but somewhat more complex reasons Piracetam may potentiate the efficacy of anti-malarial drugs at any given dosage. Piracetam, a drug known to be safe in a decade of clinical usage, merits serious study in the 3 cited diseases.

Polymyalgia rheumatica and giant cell arteritis--rational diagnosis and treatment predicated and disordered prostaglandin metabolism.

We suggest that polymyalgia rheumatica with giant cell arteritis (PR-GCA) is an arachidonic acid metabolites mediated disease which can be diagnosed more accurately and monitored more precisely for therapeutic benefits by the serial determinations of the major urinary prostaglandin F, serum urinary lysozymes, serum acid phosphatase, and serum angiotensin converting enzyme rather than by the erythrocyte sedimentation rate, and, when necessary by temporal artery biopsy. The pathogenetic role proposed for prostaglandins (PG) and, even more precisely perhaps, the leukotrienes in this disease is consistent with the several published clinical observations that non-steroidal anti-inflammatory drug treatment produces in some cases a therapeutic paradox of symptomatic relief with concurrent, if clinically silent, progression of the arteritis, even to blindness. Furthermore, the impressive response of PR-GCA to low maintenance dose steroid therapy, a clinical conundrum for decades, is rationally explained on the basis of depressed or obstructed PG metabolism early on in the metabolic cascade. These views warrant clinical evaluation, confirmation or correction in whole or in part, and may increase our understanding of PR-GCA.

Congenital X-linked incomplete achromatopsia. Evidence for slow progression, carrier fundus findings, and possible genetic linkage with glucose-6-phosphate dehydrogenase locus.

Twenty-nine members of a black kindred with congenital X-linked incomplete achromatopsia were examined; nine affected males and seven carrier females were identified. The new findings of importance are the following: (1) this congenital disorder is a slowly progressive abiotrophy, with progressive macular scarring and cone dysfunction, rather than a stationary anomaly; (2) carrier females sometimes can be found by ophthalmoscopic and fluorescein angiographic abnormalities in the macula; and (3) genetic linkage studies give evidence against linkage with the locus for the Xg blood group, but they suggest possible linkage with the glucose-6-phosphate dehydrogenase locus.

Bilateral symmetry of vision disorders in typical retinitis pigmentosa.

Bilateral symmetry of disorders of vision is examined in 60 typical patients with retinitis pigmentosa. We observed a very high degree of interocular congruence in the patterns of both kinetic visual field defects and threshold profiles and in abnormalities of foveal colour discrimination and visual acuity. Abnormalities of foveal colour vision are highly correlated with the extent of visual field loss.

X-linked ocular albinism in Blacks. Ocular albinism cum pigmento.

X-linked ocular albinism can be an unsuspected cause of congenital nystagmus in blacks. In this study, eight of ten black ocular albinos from two kindreds had nonalbinotic, moderately pigmented fundi and no transillumination of the iris. We refer to this paradoxical condition as "ocular albinism cum pigmento." The only constant ophthalmoscopic feature was a foveal hypoplasia. Biopsy of clinically normal skin to demonstrate giant pigment granules is the most accurate means of diagnosis.

Flicker fusion thresholds in Best macular dystrophy.

Flicker fusion threshold intensities were measured as a function of flicker frequency for patients with Best macular dystrophy having normal or near-normal Snellen visual acuity. These data were found to differ from normal in ways that may be interpreted to be an abnormal elevation of the foveal cone threshold, a loss of cone temporal resolution, or both. The results led to the conclusion that Best macular dystrophy affects the neurosensory retina even when Snellen visual acuity is normal.

A disposable vitreous cutter-aspirator with electronic vacuum control.

A sophisticated instrument system for performing vitreous surgery includes a disposable surgical tool, with all connecting tubing incorporated in a sterile template that is easy to assemble prior to surgery. The instrument console and foot switches provide all necessary surgical options, with a maximum degree of safety, for precise vitreous suction and infusion control with the disposable vitreophage or other available vitreous cutters.