Biomedical subjects

M Calonge

Publications and source records attributed to M Calonge.

35 records · Page 2Linked to original sources

PubMed1997

Influence of topical anesthesia on tests diagnostic of blepharitis-associated dry eye syndrome.

PURPOSE: Despite the high frequency and clinical relevance of blepharitis-associated dry-eye syndrome, no agreement exists about whether diagnostic tests should be performed with or without topical anesthesia. The aim of this study was to compare the influence of topical anesthesia on the mean values of Schirmer's test, tear lysozyme, tear lactoferrin, and tear osmolarity in patients suffering from blepharitis-associated dry eye syndrome. METHODS: The authors compared the mean values of Schirmer's test, tear osmolarity, tear lysozyme (turbidimetric assay), and tear lactoferrin (radial immunodiffusion) before and after topical anesthesia in the following groups: 56 normal subjects (group 1), 62 blepharitis patients (group 2), and 15 patients with blepharitis-associated dry eye syndrome (group 3). All clinical and laboratory tests were performed by masked observers. RESULTS: In group I, mean values of Schirmer's test decreased 24.8% (p < 0.01) when performed after application of topical anesthesia. The other tests were not significantly modified. In groups 2 and 3, significant differences were seen in Schirmer's test (25.33% and 24.19% respectively, p < 0.001) and the lysozyme determination (14.00% and 13.22% respectively, p < 0.01). Differences between the normal subjects (group I) and the patient groups increased when the tests were performed after application of topical anesthesia reaching statistical significance in group 3 for all the tests. CONCLUSIONS: Performing diagnostic tests after topical anesthesia instillation could be useful in detecting dry eye associated with blepharitis.

Adrenergic alpha-Agonists↗

PubMed1996

Effects of cationic diamidines on polyamine content and uptake on Leishmania infantum in in vitro cultures.

The effect of a series of cationic diamidines recently synthesized by Ciba Geigy, bearing diarylic (CGP040215A and CGP039937A) or monoarylic moieties (CGP033829A, CGP035537A and CGP036958A), was analyzed on some metabolic targets and cell proliferation of in vitro cultures of Leishmania infantum promastigotes (insect form). The action of these compounds on intracellular polyamine pools and putrescine transport suggests that diarylic structures were more effective than their monoarylic counterparts in depleting polyamine levels and inhibiting putrescine transport, although these processes correlate poorly with the antiproliferative rate of these compounds. Finally, the displacement of cationic diamidines to kDNA observed in the presence of several concentrations of spermidine suggests a possible combined mode of action of these molecules, first depleting intracellular polyamine pools and, then, displacing spermidine from its site of interaction to kDNA.

Animals↗

PubMed1996

Referral patterns of uveitis in a tertiary eye care center.

OBJECTIVE: To analyze the referral patterns and diagnosis of uveitis during the past decade in a large tertiary eye center. DESIGN: The records of 1237 patients with uveitis referred to the Immunology Service of the Massachusetts Eye and Ear Infirmary from 1982 to 1992 were classified and analyzed. Data regarding sex, race, nationality, referral site, ages at presentation and onset of uveitis, ocular involvement, clinical characteristics, ocular condition, and systemic disease associations were obtained. RESULTS: The mean age at onset of uveitis was 37.2 years; the male-to-female ratio was 1:1.4. Most patients were white (85.8%), born in the United States (83.1%), and referred from within New England (84.7%). Anterior uveitis was most common (51.6%), followed by posterior uveitis (19.4%), panuveitis (16.0%), and intermediate uveitis (13.0%). Chronic (58.3%), nongranulomatous (77.7%), and noninfectious (83.1%) were the most frequent types of uveitis. The most common entities included idiopathic (34.9%), seronegative spondyloarthropathies (10.4%), sarcoidosis (9.6%), juvenile rheumatoid arthritis (5.6%), systemic lupus erythematosus (4.8%), Behçet's disease (2.5%), and the acquired immunodeficiency syndrome (2.4%). CONCLUSION: The appearance of new uveitic entities, such as the acute retinal necrosis syndrome, multifocal choroiditis and panuveitis, birdshot retinochoroidopathy, and acquired immunodeficiency syndrome-related uveitis, and the reemergence of the classic infectious causes of uveitis, tuberculosis and syphilis, have changed the way we approach the diagnosis and management of posterior and panuveitis at the Massachusetts Eye and Ear Infirmary.

Adolescent↗

PubMed1996

Efficacy of nedocromil sodium and cromolyn sodium in an experimental model of ocular allergy.

BACKGROUND: Because ocular allergic disorders are important in terms of frequency and severity, there is a constant search for new topical antiallergic drugs. Nedocromil sodium has recently been introduced as a potential substitute for the mast cell stabilizer cromolyn sodium. OBJECTIVE: We compared the efficacy of topical 2% nedocromil sodium to that of 2% cromolyn sodium in treatment of the early-phase reaction of an experimental model of allergic conjunctivitis. METHODS: Guinea pigs were challenged topically with egg albumin 14 days after systemic immunization. Fifteen minutes before, immediately prior to, and 15 minutes after topical challenge, the animals received either 2% nedocromil sodium or 2% cromolyn sodium topically in one eye and phosphate buffered saline (PBS) in the other eye. Antigen-induced increase in vascular permeability was measured by the extravasation of intravenously injected Evans blue dye. Animals that were immunized and topically challenged but did not receive Evans blue were used for histologic studies. RESULTS: Evans blue extravasation from ocular tissues significantly decreased in drug-treated eyes compared with PBS-treated eyes (P < .01). Further, the cellular infiltrate (mast cells, eosinophils, and neutrophils) in the substantia propria of the conjunctiva was markedly reduced in the drug-treated eyes. No significant difference was observed between the nedocromil sodium- or cromolyn sodium-treated eyes. CONCLUSIONS: Topical 2% nedocromil sodium reduces the early-phase reaction of the allergic response as effectively as 2% sodium cromoglycate in a guinea pig model of ocular anaphylaxis.

Albumins↗

PubMed1996

Polyester nanocapsules as new topical ocular delivery systems for cyclosporin A.

PURPOSE: Nanocapsules composed of an oily core (Migliol 840) (MG) surrounded by a poly-epsilon-caprolactone (PECL) coat were evaluated as potential vehicles for the topical ocular administration of cyclosporin A (CyA). METHODS: A 2(3) experimental factorial design was applied to optimize the coating of the oily nanodroplets by a solvent displacement technique and to encapsulate a high dose of CyA. The variables investigated were: volume of oil (MG), amount of polymer (PECL), and volume of the organic solvent (acetone) used to dissolve the polymer. RESULTS: Nanocapsules had a mean size in the range of 210-270 nm, a negative zeta potential (between -55 and -60 mV) and a maximum loading capacity of 50% (CyA/PECL ratio). These highly loaded nanocapsules displayed a thick spongeous polymer coating around the oily nanodroplets. The corneal levels of CyA were up to 5 times higher for the encapsulated CyA than for the oily solution of CyA. In addition, these levels remained significantly higher than those of the control group (oily solution) for up to 3 days. Furthermore, the area-under-the-curve (AUC) values were significantly increased for the encapsulated CyA (319.98) with respect to the oily control (74.34). CONCLUSIONS: The CyA-loaded nanocapsules are shown to be interesting vehicles for the improvement of the ocular penetration of CyA.

Administration, Topical↗

PubMed1996

Putrescine active uptake system in the Trypanosomatid Crithidia fasciculata.

Using the insect Trypanosomatid Crithidia fasciculata as a model parasite of mammalian pathogenic flagellates, i.e. Leishmania and Trypanosoma spp., we have studied the kinetic and regulatory characteristics of the polyamine uptake system. Putrescine transport was age-dependent with maximum expression values at the proliferative logarithmic phase. Putrescine transport in Crithidia fasciculata was energy-dependent and against a putrescine concentration gradient. The integrity of the membrane sulfhydryl groups was absolutely required for optimum transport rates. The specificity of this mechanism was studied in the presence of a series of different chain length aliphatic diamines, showing the high specificity for putrescine and the poor effect of this series at the highest concentration analyzed as well as the higher polyamines spermidine and spermine. Finally, the well-known inhibitor of polyamine biosynthesis, DFMO, led to an upward regulation of putrescine uptake correlating with the depletion of intracellular polyamine pool. In addition, the presence of high concentrations of putrescine in the culture medium produced a downward regulation of this system.

Animals↗

PubMed1995

Inducible nitric oxide synthase in human lymphomononuclear cells activated by synthetic peptides derived from extracellular matrix proteins.

Synthetic peptides with sequences present in extracellular matrix proteins are capable of causing the expression of the inducible form of nitric oxide synthase (iNOS), detected by immunocytochemistry, and the release of NO by human lymphomononuclear cells incubated in their presence. Active peptides are 15-mers containing a characteristic 2-6-11 motif in which the amino acid residue at position 2 is Leu, Ile, Val, Gly, Ala or Lys; the residue at position 6 is always Pro; and residue 11 is Glu or Asp. The induction of iNOS in human monocytes and macrophages could be involved in the cytotoxicity against tumor cell lines also elicited by these peptides.

Amino Acid Oxidoreductases↗

PubMed1995

Experimental model of allergic conjunctivitis to ragweed in guinea pig.

An experimental model of ocular allergy was developed in the guinea pig by exposing these animals to ragweed through topical contact on nasal and conjunctival mucosae, followed by subsequent challenge with ragweed contact on the conjunctiva. Animals developed clinical and histological signs of allergy with and without the use of interleukin 4 as adjuvant. This model mimics human hay fever conjunctivitis more naturally than do animal models previously reported, and it may be subsequently more valuable in the study of the response of allergic conjunctivitis to different therapeutic approaches.

Adjuvants, Immunologic↗

PubMed1995

Calcareous corneal degeneration: report of two cases.

Band keratopathy, calcium salts in Bowman's membrane, is the most classic form of corneal calcification seen in clinical practice. However, calcareous degeneration, calcium deposition involving the full corneal thickness, is rare. We reviewed the clinical and histopathological records of two patients with severe dry eyes and calcareous corneal degeneration. In each case, complete ophthalmic examination and histopathological study were performed. Both patients had severe dry eyes, case 1 secondary to graft-versus-host disease and case 2 secondary to rheumatoid arthritis, and a persistent epithelial defect and anterior segment chronic inflammation. Both patients underwent repeated penetrating keratoplasties. Histological examination of the corneal buttons showed that calcareous corneal degeneration and band keratopathy were coincident in both cases. Both patients received postoperative medications for high-risk grafting. The mechanisms of corneal calcification may be the same in calcific band keratopathy and calcareous corneal degeneration.

Adult↗

PubMed1993

Ebulin 1, a nontoxic novel type 2 ribosome-inactivating protein from Sambucus ebulus L. leaves.

A novel type 2 ribosome-inactivating protein (RIP) that we named ebulin 1 has been isolated from leaves of Sambucus ebulus L. (Caprifoliaceae). In vitro ebulin 1 strongly inhibited protein synthesis by rabbit reticulocyte lysates, rat brain, and rat liver cell-free systems but did not affect in vitro plant nor bacterial protein synthesis. Ebulin 1 is composed of two subunits, a catalytic A subunit (M(r) 26,000) and a D-galactose-binding lectin B subunit (M(r) 30,000). Amino-terminal amino acid sequence homology revealed the novelty that the ebulin 1 A-chain shares a high degree of homology not with the A-chain of other type 2 RIPs but rather with the Cucurbitaceae type 1 RIP briodin S and the anti-human immunodeficiency virus type I proteins trichosanthin and TAP 29. Upon treatment with acid aniline the rRNA from ebulin 1-treated rabbit reticulocyte ribosomes released the RNA fragment which is diagnostic of RIP catalytic action. Ebulin 1 was nontoxic to mice up to 2 mg/kg of body weight and did not inhibit protein synthesis in cultured NHC human epithelial cells which are highly sensitive to ricin.

Amino Acid Sequence↗

PubMed1993

Isolation and partial characterization of nigrin b, a non-toxic novel type 2 ribosome-inactivating protein from the bark of Sambucus nigra L.

The bark of Sambucus nigra L. contains a non-toxic novel type 2 ribosome-inactivating protein that we named nigrin b. In vitro, nigrin b strongly inhibited mammalian protein synthesis but did not affect plant nor bacterial protein synthesis. The protein (M(r) 58,000) contains two subunits, A (M(r) 26,000) and B (M(r) 32,000); linked by disulphide bridge(s). Nigrin b was found to be an rRNA N-glycosidase of the rRNA of intact mammalian ribosomes and shares a very good N-terminal amino-acid sequence homology with the anti-HIV-1 proteins TAP 29 and trichosanthin.

Amino Acid Sequence↗

PubMed1992

Ocular surface alteration after long-term treatment with an antiglaucomatous drug.

BACKGROUND: This study was undertaken to see whether long-term locally applied ocular medications produced any alterations in the ocular surface, and, in particular, whether it caused damage to the mucus layer of the tear film. METHODS: The authors studied the ocular surface of 40 control subjects (group 1), 21 patients (group 2) chronically treated with a commercial preparation of 0.5% timolol maleate, and 20 previously untreated glaucomatous patients (group 3) in need of treatment with the same drug. Parameters studied were Schirmer's test, lacrimal meniscus height, break-up time, fluorescein and rose Bengal stains, conjunctival impression cytology, mucus staining, and the ferning test. RESULTS: Patients in groups 2 and 3 showed a significant decrease (P less than 0.001) in the number of normal Schirmer's and break-up time tests. All had positive vital stains. Results showed a significant decrease (P less than 0.001) in goblet-cell density, mucus granules, and reticular sheets, and an increase (P less than 0.001) in pathologic crystallization patterns. CONCLUSION: These results demonstrate that chronic application of a commercial preparation of timolol maleate damaged the ocular surface, especially the mucus layer of the tear film.

Administration, Topical↗

PubMed1992

Management of corneal complications in xeroderma pigmentosum.

Xeroderma pigmentosum is an uncommon, recessively inherited disorder characterized by hypersensitivity to ultraviolet (UV) radiation, with defective repair of DNA damage caused by short-wavelength radiation. Patients with this disease experience progressive and precancerous changes in sun-exposed areas of the skin and mucous membranes. Some patients develop progressive neurologic degeneration. Eye involvement includes lid, conjunctiva, and corneal disorders. We report clinical, histopathologic findings, and complex management strategies used for a 33-year-old woman with xeroderma pigmentosum and recurrent corneal ulcerations that required corneal transplantation, topical cyclosporin, perilimbic conjunctival resection followed by topical mitomycin C, and corneal dye-laser photocoagulation of neovascularization in the left eye.

Adult↗

PubMed1992

Epidermal growth factor and corneal wound healing. A multicenter study.

A randomized, double-blind, placebo-controlled, multicenter clinical trial was conducted in five centers to assess safety, ocular tolerance, and efficacy of an ophthalmic solution of epidermal growth factor (EGF) for the treatment of traumatic corneal epithelial defects. One hundred four patients completed the study: 47 received EGF and 57 placebo (the drug vehicle). Mean epithelial healing time was significantly enhanced in the EGF-treated group (44.17 h) compared with the placebo-treated treated group (61.05 h) (p < 0.01). The number of epithelial defects completely healed at 24, 48, and 72 h after the onset of treatment was significantly greater in the EGF-treated group. Local tolerance was adequate in both groups. These results indicated that topical EGF is well tolerated and may be a significant addition to the ophthalmologist's armamentarium for treating corneal epithelial defects.

Adolescent↗

PubMed1992

Vascular permeability during the early and late phases of ocular anaphylaxis.

The role of enhanced vascular permeability in a model of ocular anaphylaxis was investigated during both early- and late-phase reactions (EPR and LPR). Vascular permeability was assessed by measuring the extravascular retention of 125I-bovine serum albumin (125I-BSA) in ocular tissues. Ten groups of guinea pigs (n = 5-12 per group) were injected with dinitrophenylated (DNP) bovine gamma globulin emulsified in Freund's adjuvants and challenged after a 4-week interval by topical application of di-DNP-lysine to one eye and phosphate-buffered saline to the other eye. Thereafter, the eyes were examined and the animals were killed at different intervals after topical challenge. They were injected intravenously with 125I-BSA 0.5 hr before death. Retained radioactivity was measured separately in four tissues. The EPR (period between 0.5-1.5 hr after challenge) was characterized by enhanced retention of radioactivity in lids, conjunctiva, and orbital content. There was no significant retention of extravascular radioactivity in the globe and lacrimal gland. Thereafter (period between 2-3.5 hr after challenge), retained radioactivity was significantly diminished. The subsequent period, between 4.5-6.5 hr (LPR), was characterized by a smaller, although significant, increment of radioactivity retained in lids and conjunctiva but not in the other tissues examined. These findings indicate that enhanced microvascular permeability occurs during two phases in actively immunized guinea pigs challenged topically with di-DNP-lysine and that these phases correspond to the clinical signs that constitute the EPR and LPR of ocular anaphylaxis.

Anaphylaxis↗

PubMed1990

Atopic keratoconjunctivitis.

The clinical presentation and severe complications of atopic keratoconjunctivitis, a potentially blinding disorder, were characterized in a 9-year retrospective study of 45 patients seen at a large referral center. Twenty-six patients had subepithelial fibrosis, 13 with symblepharon and/or fornix fore-shortening. Thirty-four patients had severe keratopathy, which included neovascularization in 17 patients. Persistent epithelial defect was another major complication, occurring in 21 eyes and causing severe loss of vision. These patients required interdisciplinary therapeutic strategies; systemic antihistamine therapy and strict environmental controls were the keys to success in most cases.

Adolescent↗

PubMed1990

Early and late phases of ocular anaphylaxis in actively immunized guinea pigs.

A model of ocular anaphylaxis with distinct early- and late-phase components was studied in actively immunized guinea pigs. Twenty guinea pigs were injected with dinitrophenylated (DNP) bovine gamma globulin emulsified in Freund's complete adjuvant and challenged topically with di-DNP-lysine. Clinical signs were monitored over a 48 h period. An early-phase reaction (EPR) characterized by conjunctival edema, conjunctival erythema, lid swelling, and lid redness was observed. This reaction peaked at 0.5 h after challenge and subsided to a low point at 3-4 h. Subsequently, a second episode of lid swelling and lid redness was observed at 4-8 h. All animals in both groups exhibited an EPR. In addition, 75% of the animals underwent an EPR and an LPR. No animals exhibited an isolated LPR. Of the animals that underwent a dual response, 47% were biphasic, 6% were prolonged and 47% were multiphasic. The development of an active model of ocular anaphylaxis exhibiting both EPR and LPR components will enable studies of mechanisms which regulate the frequency and magnitude of these ocular allergic responses.

Anaphylaxis↗