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Biomedical subjects

M E Hartnett

Publications and source records attributed to M E Hartnett.

11 recordsLinked to original sources

Glaucoma as a cause of poor vision in severe retinopathy of prematurity.

Despite surgical reattachment of the retina in infants with severe retinopathy of prematurity (ROP), visual acuity may decline. We performed gonioscopy and applanation tonometry on 26 eyes of 17 infants with severe ROP who were randomly selected and followed prospectively for 2 years. Of these 26 eyes, one eye of one patient had only peripheral retinocryopexy for threshold stage III disease and had an attached retina before enrollment into the study. Sixteen infants subsequently underwent vitrectomy, scleral buckle, or both. Retinal reattachment of the posterior pole was present in at least one eye each of 10 of the 17 infants. Glaucoma was diagnosed in 5 of the 10 patients; all 5 showed a decrease in visual acuity of greater than 1 octave. Of the 5 infants without glaucoma, 3 showed visual improvement, and 2 remained the same. Although we studied a small number of cases, our results suggest that glaucoma may be a cause of visual decline in infants with severe ROP. A decline in visual acuity in infants with severe ROP and surgical retinal reattachment may warn us of glaucoma, as this diagnosis is difficult to make in these small infants.

Child, Preschool

Classification of retinal pigment epithelial detachments associated with drusen.

To understand the natural history of retinal pigment epithelial (RPE) detachments (PEDs) associated with drusen, we retrospectively reviewed 125 PEDs that had not undergone laser treatment over an average follow-up period of 28 months. We identified six types of RPE detachments: pseudo-vitelliform, confluent drusen, serous, vascular, and hemorrhagic lesions as well as PEDs associated with a retinal vascular abnormality. We correlated the type of detachment with visual acuity and anatomic outcome. The poorest results were obtained for PEDs associated with neovascularization (vascular, hemorrhagic, and retinal vascular abnormality types). Eyes presenting with pseudo-vitelliform lesions or confluent drusen had the best visual prognosis and anatomic results. Obvious subretinal new vessels developed in 16 (34%) of the serous PEDs over an average follow-up period of 25 months. Subretinal neovascularization was rare in the pseudo-vitelliform and confluent drusen groups. The proposed classification system may be useful in predicting the natural course of PEDs.

Adult

Intraocular pressure determination in infants with severe retinopathy of prematurity.

We determined intraocular pressure (IOP) in 55 premature infants (122 determinations) with stage V retinopathy of prematurity (ROP) by applanation and indentation tonometry corrected for scleral rigidity and found a modest correlation of r = 0.52 between readings. Chronologic age and the scleral rigidity coefficient were the most significant factors affecting the closeness in readings. Our findings suggest that the applanation method of obtaining IOP values is preferable in infants with ROP because this method is less affected by technical error and the variable nature of premature infant sclera. Frequent examination may be necessary to detect an early IOP increase, especially in infants who have had successful retinal reattachment through vitreoretinal techniques.

Child, Preschool

Anterior segment evaluation of infants with retinopathy of prematurity.

To understand the mechanisms of glaucoma in retinopathy of prematurity (ROP), anterior segment evaluation is essential. The authors prospectively examined the anterior segment of 27 eyes of 17 premature infants with stages IV and V ROP. Twenty-six eyes received no previous surgery or treatment. Schiøtz and applanation tonometry were performed. Structural evaluation of each anterior segment was conducted by biomicroscopy and Koeppe gonioscopy. In the 26 eyes, angle closure of greater than 180 degrees was noted in 3 (12%). The authors noted prominent Schwalbe's line in 4 eyes (15%), high iris convexity in 15 (58%), hypopigmentation of the iris root in 19 (73%), translucent matrix in the angles ("Barkan's-type" membrane) in 18 (69%), posterior synechiae in 16 (62%), visible iris or angle vessels in 12 (46%), and pigment clumping in the angle recess in 12 (46%). This study identified structural abnormalities in the anterior segment of ROP infants, including pathologic changes and anatomic features that could have a developmental origin.

Anterior Eye Segment

Comparison of the prophylactic effects of 2-deoxycytidine and prednisolone for high-dose intravenous cytarabine-induced keratitis.

In a double-masked, randomized fashion, 11 patients with hematologic malignancies received 13 courses of high-dose cytarabine therapy, intravenously (3 g/m2 every 12 hours for five to six days). Each patient received topical prednisolone phosphate 1% in one eye and 2-deoxycytidine 100 microM in the other eye every six hours. Topical therapy was initiated 12 hours before the first cytarabine dose and continued for up to ten days (until four to five days after completion of cytarabine therapy). Slit-lamp biomicroscopy was performed before therapy and then weekly for one month. 2-Deoxycytidine was equally as effective as the topical corticosteroid therapy in reducing photophobia and pain, microcysts, and punctate epithelial erosions, and each treatment gave results significantly better when compared historically to placebo-treated eyes.

Administration, Topical

Natural killer cells suppress human erythroid stem cell proliferation in vitro.

To determine the role of natural killer (NK) cells in the regulation of human erythropoiesis, we studied the effects of NK-enriched cell populations on the in vitro proliferation of erythroid stem cells at three different levels of maturation (day 14 blood BFU-E, day 5-6 marrow CFU-E, and day 10-12 marrow BFU-E). NK cells were enriched from blood by Percoll density gradient centrifugation and by fluorescence-activated cell sorting (FACS), using the human natural killer cell monoclonal antibody, HNK-1. The isolated enriched fractions were cocultured with autologous nonadherent marrow cells or blood null cells and erythropoietin in a methylcellulose erythroid culture system. Cells from low-density Percoll fractions (NK-enriched cells) were predominantly large granular lymphocytes with cytotoxic activity against K562 targets 6-10-fold greater than cells obtained from high-density Percoll fractions (NK-depleted cells). In coculture with marrow nonadherent cells (NA) at NK:NA ratios of 2:1, NK-enriched cells suppressed day 5-6 CFU-E to 62% (p less than 0.025) of controls, whereas NK-depleted cells slightly augmented CFU-E to 130% of controls (p greater than 0.05). In contrast, no suppression of day 10-12 marrow BFU-E was observed employing NK-enriched cells. The NK CFU-E suppressor effects were abolished by complement-mediated lysis of NK-enriched cells with the natural killer cell antibody, HNK-1. Highly purified HNK-1+ cells separated by FACS suppressed marrow CFU-E to 34% (p less than 0.025) and marrow BFU-E to 41% (p less than 0.025) of controls. HNK- cells had no significant effect on either BFU-E or CFU-E growth. NK-enriched cells were poor stimulators of day 14 blood BFU-E in comparison to equal numbers of NK-depleted cells or T cells isolated by E-rosetting (p less than 0.01). Interferon boosting of NK-enriched cells abolished their suboptimal burst-promoting effects and augmented their CFU-E suppressor effects. These studies provide evidence for a potential regulatory role of NK cells in erythropoiesis. The NK suppressor effect is maximal at the level of the mature erythroid stem cell CFU-E. These findings may explain some hypoproliferative anemias that develop in certain NK cell-activated states.

Adult