Biomedical subjects

J C Pastor

Publications and source records attributed to J C Pastor.

At least 37 records · Page 2Linked to original sources

PubMed1998

Analysis of human ocular mucus: effects of neuraminidase and chitinase enzymes.

PURPOSE: Our goal was to establish the characteristic migration pattern on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of high molecular weight mucins from human ocular mucus and the effects of treatment with exo- and endoglycosidases. METHODS: Chromatography by gel filtration with Sepharose CL-4B was performed on samples collected from normal subjects. Human ocular mucins from the high molecular weight fraction were digested with exoglycosidases (neuraminidase, N-acetyl-beta-D-glucosaminidase, beta-D-glucosidase) and endoglycosidases (chitinase, lysozyme); and the resulting products were analyzed by electrophoresis. Carbohydrate identification was performed using lectin probes. RESULTS: The migration of the ocular mucins on SDS-PAGE stopped after treatment with neuraminidase, which removes the terminal negatively charged sialic acid residues from mucin. Chitinase (beta(1-4)N-acetylglucosaminidase) treatment increased the electrophoretic migration of mucins. Staining with wheat germ agglutinin and Maackia amurensis agglutinin lectins showed that these mucins contain beta(1-4)NAcGlc and SAa(2-3)Gal linkages. CONCLUSIONS: These studies demonstrate that the mobility of human ocular mucins on SDS-PAGE is determined by their intrinsic total negative charge and is not dependent on SDS treatment. It is interesting to note that human ocular mucus contains chitinous material resistant to lacrimal lysozyme, which is accessible to chitinase, an enzyme now found to degrade human ocular mucins. These chitinous linkages could be in part responsible for the mucus resistance.

Adolescent↗

PubMed1997

Characterization of epithelial primary cultures from human conjunctiva.

Primary cultures of human epithelial cells from normal conjunctiva were developed and characterized to determine whether they retained epithelial characteristics. Conjunctival explants were obtained from the upper fornix of healthy donors and cultured in supplemented DMEM/F-12 medium for 5 days. The epithelial outgrowth was maintained for an additional 10 days. Primary cultures were then processed for light microscopy, transmission and scanning electron microscopy (TEM, SEM), and immunocytochemistry. They exhibited typical features of conjunctival epithelium on light microscopy (polygonal morphology, intimate cohesion, production of mucins), TEM (abundant desmosomes, keratin bundles, granules, microvilli), SEM (polygonal shape, microvilli, intimate cohesion), and immunocytochemistry (positivity for the receptor of epidermal growth factor, desmosomal proteins, and cytokeratins). In conclusion, primary cultures developed from normal human conjunctiva maintained the epithelial characteristics in vitro. Because the conjunctiva is a major component of the anterior ocular surface, we propose this in vitro system as suitable for physiopathologic and toxicologic studies.

Antibodies, Monoclonal↗

PubMed1997

Value of logistic discriminant analysis for interpreting initial visual field defects.

PURPOSE: The authors evaluate logistic discriminant analysis as a method for interpreting visual field results in initial stages of several ophthalmic diseases. METHODS: The authors retrospectively studied the visual field defects of 96 patients with early glaucomatous damage and prospectively studied 84 subjects with normal eyes (n = 28), cataracts (n = 27), diabetic retinopathy (n = 14), or hypertensive retinopathy (n = 15). The visual fields were examined at least twice with program G1 of Octopus 500 (Interzeag AG, Schlieren, Switzerland). Only one eye per patient was randomly selected and included in the study. The authors created a database with all visual field information provided by Octopus and applied logistic discriminant analysis (SAS Logistic Procedures, SAS Institute, Cary, NC) to obtain classification rules capable of qualifying visual field defects as glaucomatous or nonglaucomatous. The rules were tested with an independent sample. RESULTS: There were significant differences between the groups in the distribution of visual field defects tested by program G1. Logistic discriminant analysis correctly identified the glaucomatous or nonglaucomatous origin of the defects with a sensitivity of 65% to 85% and a specificity of 60% to 92%. CONCLUSIONS: Logistic discriminant analysis is a useful tool to aid in the interpretation of early glaucomatous and nonglaucomatous visual field defects.

Data Interpretation, Statistical↗

PubMed1997

The role of retinotomy in an experimental rabbit model of proliferative vitreoretinopathy.

PURPOSE: To create a model of proliferative vitreoretinopathy (PVR) using retinotomy with vitrectomy, cryotherapy, and platelet-rich plasma (PRP) injection, which more closely resembles the human pathophysiologic condition. METHODS: One hundred and twenty albino rabbits were divided into 10 groups of 12 rabbits each and underwent the following procedures: group 1, vitrectomy; group 2, cryotherapy; group 3, PRP intravitreous injection; group 4, retinotomy; group 5, retinotomy and vitrectomy; group 6, retinotomy and cryotherapy; group 7, retinotomy and PRP injection; group 8, retinotomy, vitrectomy, and cryotherapy; group 9, vitrectomy, cryotherapy, and PRP injection and group 10, retinotomy, vitrectomy, cryotherapy, and PRP injection. All animals underwent follow-up examinations with indirect ophthalmoscopy and fundus photography on days 1, 3, 7, 10, 14, 21, and 28 after the procedure(s). Retinal changes were categorized according to the classification of Fastenberg et al. At the end of the experiments, the eyes were enucleated, and examined under light and electron microscopy. RESULTS: No retinal detachments (RDs) were observed in groups 1, 2, 4, 5, 6, and 8. RDs of varying severity were observed in group 3 (n = 1), group 7 (n = 2), group 9 (n = 6), and group 10 (n = 12). Light and transmission electron microscopy confirmed the findings. CONCLUSIONS: Combining retinotomy with vitreous removal, cryotherapy, and PRP injection creates an efficient and different model of PVR that produced RD in 100% of rabbit eyes.

Animals↗

PubMed1997

Porcine model of proliferative vitreoretinopathy with platelets.

PURPOSE: To develop an experimental model of proliferative vitreoretinopathy (PVR) in the pig, and determine the efficacy of platelet-derived growth factor (PDGF) compared with different platelet plasma concentrates in its development. METHODS: Animals were divided into four groups of 12 pigs each. Group 1, 2, and 3 underwent four 3-mm-long retinotomies, a partial mechanical vitrectomy, and six transconjunctival retinal cryoapplications and were injected intravitreally with, respectively, 0.2 ml of platelet rich plasma, 0.2 ml of a solution containing 200 ng of porcine PDGF, and 0.2 ml of platelet concentrated plasma. Group 4 received only an intravitreal injection of 0.2 ml of porcine PDGF. RESULTS: In Group 1, retinal detachments (RDs) developed in six eyes (50%) (two eyes, total RDs; four, extensive RDs). In Group 2, focal RDs developed in six eyes (50%). In Group 3, 11 eyes (92%) developed Rds (six eyes, total RDs; three, extensive RDs, two, focal RDs). Group 4, did not develop lesions. Statistically significant differences were found between Group 3 and the other groups. Group 2 RDs were associated with the presence of vitreoretinal membranes but there were no signs of PVR. In Groups 1 and 3, signs of anterior PVR, posterior PVR, and retinal holes with rolled edges were observed. CONCLUSIONS: We have developed a model of PVR in the pig, the retina of which more closely resembles that of humans. Platelet plasma more effectively contributed to the development of an experimental model of porcine PVR than 200 ng of PDGF. The efficacy depends on the platelet concentration of the plasma. These results suggest that other growth factors and plasma components may interact synergistically with PDGF in the pathogenesis of PVR.

Animals↗

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

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↗

PubMed1995

Tolerance of intravitreous interleukin-1 beta in the treatment of experimental vitreous hemorrhage.

We investigated the tolerance of human recombinant interleukin-1 beta (IL-1 beta) injected intravitreously and its putative role in the clearance of experimental vitreous hemorrhages. Three groups of 10 pigmented rabbits each were injected intravitreously with 0.1 ml autologous whole blood. Mean fundus revisualization times after blood clouding were as follows: group 1 (controls, blood injection only), 5.3 weeks; group 2 (100 units of IL-1 beta injected intravitreously 7 days after blood injection), 3.3 weeks; group 3 (1,000 units of IL-1 beta injected intravitreously 7 days after blood injection), 3.2 weeks. Group 4 (10 rabbits) was injected only with 1,000 units of IL-1 beta. Clinical examinations showed a transient mild inflammatory reaction in group 2 and a transient severe reaction in groups 3 and 4. Vitreous opacities, a whitish retinal reaction and vascular changes were seen in group 4. Electroretinography did not show a b-wave decrease in any group. These results suggest that low concentrations of IL-1 beta may be useful for nonsurgical treatment of human vitreous hemorrhage.

Animals↗

PubMed1994

[Ureteral endometriosis. Report of a case].

Presentation of one case of ureteral tumour with the patho-anatomical label of intrinsic multifocal endometriosis, who underwent surgical treatment. Endometriosis is a clinic-gynaecological problem affecting 10-20% of pre-menopausal women. The urinary tract compromise happens in 1-10% of women with endometriosis. In spite of being an uncommon pathology, early diagnosis is of great importance due to the large number of non-saveable kidneys that it causes (25-43%). In our opinion, in cases with established fibrosis we regard surgery as the choice therapy. A presentation is made of the clinical case, pathological anatomy, treatment and comments on the disease.

Adult↗

PubMed1993

Efficacy of intravitreous interleukin-1 in the reabsorption of experimental vitreous hemorrhage in rabbits.

A low degree of phagocytosis in the vitreous is considered a major cause of the inadequate spontaneous removal of vitreous hemorrhage. We investigated the putative role of natural human interleukin-1 (IL-1) in the clearance of experimental vitreous hemorrhage and compared it with that of retinal cryotherapy. Five groups of 10 albino rabbits each were injected intravitreously with 0.1 ml autologous whole blood. Mean fundus revisualization times after blood clouding were as follows: group 1 controls (blood injection and no further manipulation), 6.1 weeks; group 2 (transconjunctival cryoapplication 7 days after blood injection), 4.3 weeks; group 3 (natural human IL-1 injected into the vitreous 7 days after blood injection), 3.8 weeks; group 4 (cryoapplication and IL-1 seven days after blood injection), 3.7 weeks; group 5 (intravitreous injection of phosphate-buffered saline), 4.1 weeks. Differences were statistically significant at week 4 of follow-up (p < 0.01). Two additional groups were used to estimate the possible toxicity of IL-1 (group 6) and PBS (group 7). Clinical and histologic examinations found no intraocular alterations imputable to IL-1. These results suggest that IL-1 may be used for nonsurgical treatment of human vitreous hemorrhage.

Absorption↗

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

Reduction of cardiovascular side effects associated with ocular administration of metipranolol by inclusion in polymeric nanocapsules.

A new formulation of metipranolol base for ophthalmic administration was developed consisting of a colloidal suspension of polyepsiloncaprolactone nanocapsules with an oily core (Migliol 840) in which the drug is dissolved. Physicochemical properties of the nanocapsules show that the polymer coating around the oily droplets causes an important reduction of the droplet size, with no significant modification of the surface charge noted. When this formulation was administered to rabbits, a reduction of intraocular pressure similar to that seen with commercial eye drops was observed. Nevertheless, the evaluation of the cardiovascular side effects clearly showed lower conjunctival absorption of the encapsulated drug compared with the commercial drops. The direct (bradycardia) and the indirect evaluation (based on the study of the influence on the hypotensive and positive chronotropic effects of isoprenaline) showed that blockage of beta-adrenoreceptors was reduced greatly by the topical administration of the new formulation.

Animals↗

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

Intravitreal silicone and fluorosilicone oils: pathologic findings in rabbit eyes.

The effects of medical-grade intraocular silicone and commercial-grade fluorosilicone oils were studied in rabbit eyes. The experimental model consisted of lensectomized and vitrectomized eyes that did not undergo further treatment (Group 1), and three groups of lensectomized and vitrectomized eyes that were injected intravitreously 3 months earlier with medical-grade silicone oil of 1000 cs (Group 3), and 10,000 cs (Group 4). The silicone oil-injected eyes developed proliferative membranes. The fluorosilicone oil caused an intravitreous inflammatory reaction with vacuolated macrophages present around the oil that may have been due to the higher concentration of low-molecular-weight components found in the oil.

Animals↗

PubMed1992

Intraocular irrigating solutions and vitrectomy-related changes (in protein, lactic and ascorbic acid) in rabbit vitreous.

Vitrectomy and the subsequent vitreous fluid exchange alter the chemical and physical properties of the vitreous. This study assessed the time course alterations of total protein, ascorbic acid and lactic acid in the rabbit vitreous cavity following vitrectomy. Normal values were 2.2 +/- 1.2 mg/ml, 8.5 +/- 1.0 mg/100 ml and 16.8 +/- 3.5 mumol/ml, respectively. Nine groups of 5-10 adult albino rabbits underwent closed vitrectomy using physiologic saline, Ringer's lactate and BSS plus solutions. Samples were withdrawn at 3 and 24 h and 7 days after vitrectomy. Total protein levels increased in all groups at 3 and 24 h (20-30 mg/ml). Ascorbic acid measurements at 24 h rose only with saline and BSS plus. At 24 h the BSS plus group was the only one demonstrating an increased lactic acid concentration.

Animals↗

PubMed1992

Intravitreal and subretinal proliferation induced by platelet-rich plasma injection in rabbits.

We developed an experimental model of proliferative vitreoretinopathy (PVR) in albino rabbits by combining some factors suspected of causing the disease. Sixty nine eyes divided into six groups served as controls (Groups C 1-6). Forty nine eyes were divided into four experimental groups (Groups E 1-4). Group E1 (n = 12) was injected with 0.15 ml of platelet-rich plasma. In addition, Groups E2 (n = 12) and E3 (n = 12) underwent cryotherapy or vitrectomy. Group E4 (n = 13) underwent both procedures. Seven of the 13 Group 4 experimental eyes developed total retinal detachment and giant holes. None of the other groups developed more than two total retinal detachments or giant holes (P < 0.05). Light and electron microscopy showed intravitreal or preretinal proliferation composed of fibroblast-like cells. Retroretinal membranes appeared only in Group E4 eyes, composed of elongated cells with oval nuclei and abundant organelles in the cytoplasm. We believe these lesions mimic human PVR more closely than other models previously developed.

Animals↗

PubMed1991

Retinal cryoapplication and fibrinolysis in experimental vitreous hemorrhage.

Retinal cryoapplication accelerates blood resorption of experimental vitreous hemorrhages shortening the time until fundus visualization is possible. For the animals that underwent cryoapplication five days after blood injection into the vitreous cavity, the mean time to fundus visualization was 3.75 weeks versus 5.06 weeks for the control group (p less than 0.001). Retinal cryoapplication also causes an increase in the concentration of fibrin degradation products in the vitreous cavity, indicating an activation of fibrinolysis, one of the most important processes involved in hemorrhage resolution. Use of topical indomethacin slightly lessens the effect of cryoapplication on acceleration of blood resorption (mean 4.06 weeks until visualization), but does not influence the effect on fibrinolysis.

Administration, Topical↗