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Biomedical subjects

J Sugar

Publications and source records attributed to J Sugar.

At least 91 records · Page 5Linked to original sources
PubMed1990

Familial trigeminal anesthesia.

Familial congenital trigeminal anesthesia as an isolated abnormality is an unusual disorder. To our knowledge, only one family has previously been reported. We report here a family with three affected members demonstrating facial anesthesia, bilateral corneal changes, and nasal septal damage secondary to self-traumatization. Magnetic resonance imaging demonstrated hypoplasia of gasserian ganglia and trigeminal nerves in the affected father of two affected sons. The pathogenesis of this disorder appears to be congenital hypoplasia of the trigeminal nerves and gasserian ganglia that is inherited in a dominant fashion.

Adult↗
PubMed1990

Respiratory epithelium in a cystic choristoma of the limbus.

A female newborn had a cystic, whitish gray mass at the inferotemporal limbus of the left eye. At age 3 weeks, the newborn underwent excision of the tumor, corneal patch grafting, and superior sector optical iridectomy. Histopathologic and electron microscopic examination of the excised tissue revealed a choristoma consisting of cysts lined with respiratory epithelium. To our knowledge, respiratory epithelium in a limbal choristoma has not been previously reported.

Choristoma↗
PubMed1990

Alpha-1 proteinase inhibitor levels in keratoconus.

The levels of alpha 1-proteinase inhibitor (alpha 1-antitrypsin) in keratoconus, normal human, and other diseased corneas were examined. Using an immunoperoxidase technique, the presence of this inhibitor was demonstrated in the epithelium, stroma and endothelium of all corneal sections. Compared with normal human controls, the staining intensity in the epithelium and stromal lamellae of keratoconus corneas was markedly reduced. Such a reduction was not seen in either scarred or other diseased corneas. Extracts of keratoconus and normal human corneas were subsequently analyzed for alpha 1-proteinase inhibitor by a dot blot assay using a monoclonal antibody against the inhibitor and a 125I-labelled secondary antibody. In agreement with the immunohistochemical findings, the alpha 1-proteinase inhibitor level found in the epithelium of keratoconus corneas was approximately one-fourth of that found in normal human controls. In addition, the stromal extracts of keratoconus corneas contained about one-sixth the inhibitor level of that in normal human extracts. These results lend further support to the hypothesis that degradation processes may be aberrant in keratoconus.

Adolescent↗
PubMed1990

Neutral glycosphingolipids isolated from porcine corneas.

Six neutral glycosphingolipids were isolated from porcine corneas using silicic acid column chromatography and preparative thin-layer chromatography. Five of these glycolipids were partially identified by gas-liquid chromatography. Two were glucosylceramides, two were lactosylceramides and one was tetrahexosylceramide containing galactose, glucose and N-acetylgalactosamine in the molar ratio of 2:1:1. Glucosylceramides were found to be the predominating component, with lactosyl- and tetrahexosylceramides being the minor constituents. Sphingosine was the major long-chain base in all fractions. The fatty acids of the corneal neutral glycosphingolipids were variable in chain length. This represents the first investigation of neutral glycosphingolipids in corneas of any species.

Animals↗
PubMed1990

Comparison of the effects of two viscoelastic agents, Healon and Viscoat, on postoperative intraocular pressure after penetrating keratoplasty.

Sixty-two patients undergoing penetrating keratoplasty were randomized to receive Healon (1% sodium hyaluronate) or Viscoat (3% sodium hyaluronate and 4% chondroitin sulfate) as a means of maintaining the anterior chamber during surgery. Neither viscoelastic agent was irrigated from the eye at the end of the procedure. Intraocular pressures (IOPs) were measured at 4, 10, 24, and 72 hours postoperatively. For the Healon group, IOPs were 16.52, 23.50, 28.31, 23.27, and 16.03 mm Hg at baseline and at the four follow-up periods, respectively. For the Viscoat group, they were 19.10, 28.33, 23.48, 18.62, and 16.17 mm Hg at those points, respectively. IOPs were significantly elevated over baseline in the Healon group at 4, 10, and 24 hours, and in the Viscoat group at 4 and 10 hours. There were no statistically significant differences between the Healon and Viscoat groups at 4, 10, and 72 hours. At 24 hours, the Healon group had a mean pressure rise over baseline of 6.5 mm Hg, while the Viscoat group had returned to baseline levels (P = .02). We conclude that both Healon and Viscoat raise postoperative IOPs, but that Healon appears to elevate IOPs for a longer period after surgery than Viscoat.

Adolescent↗
PubMed1990

The effect of flurbiprofen on herpes simplex virus type 1 stromal keratitis in mice.

The use of steroidal compounds to reduce the inflammation and scarring associated with herpes simplex virus type 1 (HSV-1) stromal keratitis can result in severe exacerbation of the corneal disease. We compared the nonsteroidal anti-inflammatory drug (NSAID) flurbiprofen sodium with dexamethasone for the treatment of HSV-1 induced corneal stromal disease in an inbred mouse model. Stromal disease was induced by the direct intrastromal injection of HSV-1. A stromal opacity and corneal neovascularization (CNV) developed in 100% of the injected eyes, with no epithelial involvement until late in the course, when the stromal disease was quite severe, such that it was possible to test the effectiveness of drugs in animals with an intact epithelium. Dexamethasone treatment had a variable effect on the severity of disease, ranging from a significant reduction in severity to significant exacerbation of disease, compared with placebo-treated controls. The most frequent effect of dexamethasone treatment was a worsening of corneal stromal opacities and CNV. In contrast, treatment with the NSAID did not exacerbate HSV-1 stromal disease. Flurbiprofen treatment resulted in a significant reduction of the maximum intensity of stromal opacity in some experiments, whereas in other experiments the effect was not statistically significant. In vitro studies of the effect of the anti-inflammatory drugs on HSV-1 replication in Vero cells revealed that both dexamethasone and flurbiprofen inhibited HSV-1 replication in a dose-dependent manner. Flurbiprofen had a greater inhibitory effect, which appears to be due, at least in part, to a direct virucidal effect. Dexamethasone did not exhibit virucidal activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Lysosomal enzyme abnormalities in keratoconus.

We studied the lysosomal enzyme activities in corneas obtained from 12 patients with keratoconus. Three acid hydrolases--acid phosphatase, acid esterase, and acid lipase--were demonstrated by histochemical staining methods in the epithelium, stroma, and endothelium of corneas with keratoconus and normal human corneas. Analyses by an image-processing system indicated that the epithelium, especially the basal epithelium, of corneas with keratoconus had significantly higher levels of acid phosphatase, acid esterase, and acid lipase than those in normal human controls. Such an abnormality was not seen in either scarred corneas or corneas obtained from patients with Fuchs' corneal dystrophy. Our finding is consistent with the hypothesis that tissue degradation processes may be abnormal in keratoconus. In addition, our data suggest that the corneal epithelium, as previously speculated, may also be involved in this corneal disease.

Acetylesterase↗
PubMed1989

Herpes simplex keratitis in patients with acquired immune deficiency syndrome.

Acquired immune deficiency syndrome (AIDS) is associated with a wide spectrum of systemic and ocular infectious diseases. Little information is known about herpes simplex virus type 1 (HSV-1) keratoconjunctivitis in association with AIDS. The authors present six cases of recurrent HSV keratitis occurring in AIDS patients. Features of the herpetic keratitis in these patients included unilateral dendritic or geographic epithelial keratopathy; predilection for peripheral versus central corneal involvement; one to three recurrences per patient over a mean observation period of 17 months, with a median dendrite-free interval of 7 months; and a moderately prolonged clinical course with a median healing time of 3 weeks using topical antiviral therapy. Only one of six cases had stromal infiltrative involvement. These cases raise the question of whether the immunologic abnormalities associated with AIDS may affect the clinical characteristics and course of HSV keratitis.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Immunohistochemical studies of Peters' anomaly.

Peters' anomaly is a congenital abnormality that affects mainly the posterior cornea. The pathogenesis is unclear. By immunohistochemical methods, the authors determined the presence of extracellular matrix proteins, including fibronectin, laminin, and collagen types I, III, IV, V, and VI, in seven corneal buttons from five patients with Peters' anomaly. Type III collagen was the only protein absent in either the pathologic or normal human corneas. Compared with normal controls, the stromal lamellae in Peters' anomaly corneas were more irregular and more closely packed. In addition, the fibronectin staining was markedly enhanced in all seven Peters' anomaly corneas. Staining with collagen type VI was also mildly increased. These results suggest that extracellular matrix elements such as fibronectin may be important factors in this developmental disorder.

Aged↗
PubMed1989

Growth of human corneal endothelial cells in culture.

We investigated the effects of various culture conditions on the growth of normal human corneal endothelial cells in culture. Falcon Primaria tissue culture plastic was found to provide a more suitable surface for endothelial cell growth than the conventional Corning tissue culture plastic. Also, media containing 10% fetal bovine serum and 5% calf serum (complete media) facilitated the growth of human cells better than those containing Nu-serum. Supplementation with epidermal or fibroblast growth factor (10 and 100 ng/ml) to the complete media had no effect on human endothelial cell growth. Chondroitin sulfate at low concentrations (100 micrograms/ml to 1 mg/ml) also showed little effect. At high concentrations (13.5 and 25 mg/ml), however, chondroitin sulfate significantly promoted human corneal endothelial cell growth during a 1- to 2-week incubation period. From the 37 cultures initiated, outgrowth from explants appeared within 3 to 7 days. Cells were polygonal in shape and, at confluency, formed a continuous monolayer. We attained a success rate of 87% (7/8) growing primary cultures from donors under 20 years of age and a 59% (17/29) success rate from older donors.

Adult↗
PubMed1988

Pseudophakic bullous keratopathy with Intermedics model 024 (Hessburg) anterior chamber intraocular lenses.

We report the development of pseudophakic bullous keratopathy in 18 eyes following implantation of Pharmacia Intermedics Ophthalmics model 024 (Hessburg) anterior chamber intraocular lenses. Eight of these intraocular lenses were implanted during uncomplicated intracapsular cataract extractions. Mean onset of corneal edema was 21.4 months after lens implantation. Patients with this type of lens already implanted in their eyes require close follow-up for complications.

Aged↗
PubMed1988

Heterogeneity in macular corneal dystrophy.

Macular corneal dystrophy is an autosomal recessive disorder in which abnormal deposits in the corneal stroma have been identified. We examined the corneal buttons of 12 patients, who had clinical features of macular dystrophy, by histochemical staining, transmission electron microscopy, and immunohistochemical techniques. All corneas exhibited positive staining with Muller Mowry's colloidal iron. Using monoclonal antibodies 1/20/5-D-4, J-10, J-19, and J-36 that recognize specific sites on the sulfated keratan sulfate molecule, we stained corneal sections by an avidin-biotin-peroxidase complex method and identified two groups of macular corneal dystrophy. One group consisting of four corneas reacted positively with all four antibodies, and the other group consisting of eight corneas did not react with any of the antibodies used. These results confirmed those recently presented by Yang et al that there may be subgroups of macular dystrophy that can be identified by immunohistochemical methods. Also, serum levels of sulfated keratan sulfate were determined in seven patients. One patient who displayed a normal level of serum keratan sulfate had positive corneal immunoreactivity. Of the six patients who lacked serum keratan sulfate, four showed negative and two had positive corneal immunostaining, suggesting at least three subgroups in the disease. An attempt was made to correlate the clinical features, histochemical-staining characteristics, and ultrastructural morphology with the immunoreactivity to keratan sulfate antibodies, but no correlations could be made.

Adult↗
PubMed1988

Glycoconjugate abnormalities in cultured keratoconus stromal cells.

We examined the plasma membrane glycoconjugates of cultured corneal stromal cells derived from patients with keratoconus and healthy subjects. Using radiolabeled lectins as probes, we found that a majority of our keratoconus strains contained more binding sites for concanavalin A, Ricinus communis agglutinin I, and soybean agglutinin than did the controls. The number of binding sites in cultured keratoconus cells for radioactive peanut agglutinin, wheat germ agglutinin, and Griffonia simplicifolia agglutinin I, however, was similar to that found in normal controls. Using a second method with biotin-labeled lectins as probes, we confirmed that increased amounts of glycoconjugates would bind to concanavalin A and R communis agglutinin I in stromal cells of patients with keratoconus compared with those of the control subjects. This study suggests that plasma membranes of cells derived from some patients with keratoconus may contain elevated amounts of glycoconjugates with glucose and/or mannose, terminal galactose, and N-acetylgalactosamine residues.

Adolescent↗
PubMed1988

Nanophthalmic sclera. Fibronectin studies.

The authors performed fibronectin studies on scleral specimens derived from a patient with nanophthalmos. Immunohistochemical staining with antifibronectin was conducted using both formaldehyde-fixed, paraffin-embedded tissue sections and unfixed tissue-cultured scleral cells. In each case, the nanophthalmic samples exhibited fibronectin staining stronger than that obtained from normal human subjects. Results from an enzyme-linked immunosorbent assay (ELISA) confirmed the histologic findings that, in tissue culture, the patient's scleral cells contained and secreted a higher amount of fibronectin than did the normal control cells. The elevated fibronectin level may be related to the development of nanophthalmos.

Adult↗
PubMed1988

Induction of erythroid differentiation and modulation of gene expression by tiazofurin in K-562 leukemia cells.

Tiazofurin (2-beta-D-ribofuranosyl-4-thiazole-carboxamide; NSC 286193), an antitumor carbon-linked nucleoside that inhibits IMP dehydrogenase (IMP:NAD+ oxidoreductase; EC 1.1.1.205) and depletes guanylate levels, can activate the erythroid differentiation program of K-562 human leukemia cells. Tiazofurin-mediated cell differentiation is a multistep process. The inducer initiates early (less than 6 hr) metabolic changes that precede commitment to differentiation; among these early changes are decreases in IMP dehydrogenase activity and in GTP concentration, as well as alterations in the expression of certain protooncogenes (c-Ki-ras). K-562 cells do express commitment-i.e., cells exhibit differentiation without tiazofurin. Guanosine was effective in preventing the action of tiazofurin, thus providing evidence that the guanine nucleotides are critically involved in tiazofurin-initiated differentiation. Activation of transcription of the erythroid-specific gene that encodes A gamma-globin is a late (48 hr) but striking effect of tiazofurin. Down-regulation of the c-ras gene appears to be part of the complex process associated with tiazofurin-induced erythroid differentiation and relates to the perturbations of GTP metabolism.

Antimetabolites, Antineoplastic↗
PubMed1988

Changes in pancreatic B cell function during late pregnancy, early lactation and postlactation.

Oral glucose tolerance tests were performed in 10 normal women during late pregnancy (36 +/- 1 weeks of gestation), early lactation (5 days after delivery) and postlactation (1 week after weaning). A marked decrease in basal plasma insulin and C peptide concentrations, as well as in the B cell secretory response to hyperglycemia, was observed at the 5th day of postpartum, compared to the high values recorded in late pregnancy. Except for a higher basal C peptide level and a lower plasma prolactin concentration, there was no major difference between early lactation and postlactation. At the 5th day after delivery, the insulin response to hyperglycemia was lower in lactating than in nonlactating women (14 subjects in each group). It is concluded that, in normal women, pancreatic B cell function undergoes a rapid normalization during the postpartum, at least when the latter coincides with the onset of lactation.

Adult↗