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J M Larrosa

Publications and source records attributed to J M Larrosa.

32 records · Page 2Linked to original sources
PubMed1999

Quantification of intraoperative administration of mitomycin-C in filtering surgery with surgical sponge material.

PURPOSE: To determine the absorption and release of mitomycin-C 0.4 and 0.2 mg/mL from sponge-like specimens of Spongostan film (Ferrosan, Copenhagen, Denmark) and the scleral and conjunctival impregnation in an experimental model of filtering surgery. METHODS: The maximum amount of mitomycin per volume unit that Spongostan is able to absorb was determined physically as the difference between dry weight and soaked weight. Mitomycin-C activity in known volumes of Spongostan after mitomycin-C release in vitro also was determined at 0, 1, 10, and 30 seconds and 1, 3, 5, 10, 15, and 30 minutes. Antibiotic activity of the specimens was evaluated by means of bioassay. Millimeters of inhibition of bacterial growth were related to microg of mitomycin activity according to a reference curve obtained from known amounts of mitomycin-C. Finally, 10 eyes of 10 rabbits underwent filtering surgery with intraoperative application of mitomycin by means of the Spongostan film. The Spongostan implants then were removed and tested for mitomycin activity. Scleral and conjunctival specimens were obtained for bioassay. RESULTS: The maximum capacity of 25 mm2 x 0.5 mm thick Spongostan films saturated in 0.4 and 0.2 mg/mL solutions of mitomycin-C were 8.49 microg and 4.23 microg, respectively. Biologic activity (bioassay determination) was 8.24 microg and 4.19 microg of mitomycin-C, respectively. In vitro release of mitomycin was gradual until 30 minutes. In vivo mitomycin release from Spongostan after 5 minutes was 6.91 microg. Impregnation with the antimitotic was better in conjunctiva than sclera. CONCLUSION: Bioassay permits quantification of mitomycin-C activity. The release from sponge specimens is gradual, and impregnation was better in conjunctiva than sclera.

Absorption↗
PubMed1999

Correlation of functional and structural measurements in eyes suspected of having glaucoma.

PURPOSE: This study was conducted to determine the correlation between structural changes in the retinal nerve fiber layer (RNFL) and functional loss detected on short-wavelength automated perimetry (SWAP) in a population of patients with suspected glaucoma. METHODS: With a selection criteria of intraocular pressure (IOP) more than 21 mmHg and normal results of conventional automated perimetry, 49 eyes of 49 patients with ocular hypertension were enrolled in the study. The SWAP was performed with a modified Humphrey field analyzer, and visual field indexes (mean deviation [MD], corrected pattern standard deviation [CPSD]) were calculated. Semiquantitative RNFL scores were given separately to diffuse and localized defects of the RNFL. RESULTS: The MD increased significantly with higher diffuse and total RNFL scores, with good correlation coefficients. A weak correlation was found between CPSD and diffuse, total, and localized RNFL scores. CONCLUSION: Diffuse RNFL loss are associated with abnormalities in visual field indexes (MD), whereas focal structural damage showed no correlation with visual field loss.

Adult↗
PubMed1998

Short-wavelength automated perimetry and retinal nerve fiber layer evaluation in suspected cases of glaucoma.

OBJECTIVES: To determine if short-wavelength automated perimetry (SWAP) provides evidence that indicates early functional losses in ocular hypertensive subjects and to establish a direct comparison with early structural abnormalities in the retinal nerve fiber layer (RNFL). METHODS: A total of 160 eyes belonging to 83 patients with ocular hypertension (intraocular pressure >21 mm Hg and normal results on standard automated perimetry evaluation), on which a SWAP and RNFL study were performed, were examined. One hundred twenty-eight age-matched subjects without ocular hypertension were evaluated to establish the 95% and 99% confidence intervals at each of the 76 exploration points of the SWAP test. RESULTS: The RNFL study results were normal in 83 cases (51.8%) and pathologic in 77 cases (48.1%). The SWAP results were pathologic in 57 cases (35.6%). Significant differences (P<.001) were observed when comparing the distribution of normal and pathologic SWAP results among the types of defects in the RNFL (focal wedge, diffuse atrophy, and mixed atrophy). CONCLUSIONS: Short-wavelength automated perimetry is a useful test for the early detection of visual field losses. It is more sensitive than standard automated perimetry and provides a high association with RNFL assessment, which has proved capable of detecting signs of glaucomatous damage several years before the onset of the typical visual field defects.

Adult↗
PubMed1998

Subconjunctival injection of low doses of mitomycin C: effects on fibroblast proliferation.

We evaluated the effect of low doses of mitomycin C (MMC) in subconjunctival injection on fibroblast viability. Eighteen rabbits received subconjunctival injections: group 1 was injected with balanced salt solution (BSS), group 2 received MMC 0.025 mg, and group 3 MMC 0.005 mg. Tissue samples were taken 1 h after the injection (conjunctiva, sclera and cornea at 0 and 90 degrees) and cultured. The average scleral and conjunctival outgrowth in the MMC-treated groups was significantly inferior to the outgrowth of the samples treated with BSS. Subconjunctival injections of MMC (0. 025 and 0.005 mg) have an inhibitory effect on conjunctiva at 0 degrees and on scleral fibroblast populations.

Animals↗
PubMed1997

13-cis-retinoic acid in silicone-fluorosilicone copolymer oil in a rabbit model of proliferative vitreoretinopathy.

The purpose of this study was to evaluate the effect of 13-cis-Retinoic Acid (RA) in Silicone-Fluorosilicone Copolymer Oil (SiFO) in a rabbit model of proliferative vitreoretinopathy (PVR). Rabbits underwent gas-compression vitrectomy. During gas-SiFO exchange, group 1 was injected with 1 ml (10 microg ml-1) 13-cis-RA in SiFO, group 2 with 1.5 ml (9 microg 1.5 ml-1) all-trans-RA in SiFO, group 3 with 1 ml SiFO alone, and group 4 with balanced salt solution (BSS). Groups 1-4 were also injected with 0.1 ml suspension of fibroblasts (75,000 0.1 ml-1) and 0.05 ml platelet rich plasma (70,000 0.1 ml-1), and were observed for 4 weeks. Group 5 was injected with SiFO alone, group 6 with 1 ml (10 microg ml-1) 13-cis-RA in SiFO, group 7 with 1.5 ml (9 microg 1.5 ml-1) all-trans-RA in SiFO, and group 8 with BSS. After 4 weeks, groups 5-7 underwent SiFO-BSS exchange. ERG and histopathology were performed to test for retinal toxicity in groups 5-8. The incidence of traction retinal detachment at 4 weeks was: group 1, 42.9%; group 2, 36.4%; group 3, 87.5%; and group 4, 88.9%. A significant difference in the incidence of PVR was noted between treated eyes (groups 1 and 2) and control eyes (groups 3 and 4) at 2, 3, and 4 weeks (P<0.05). No significant difference in the incidence of PVR was found between groups 1 and 2 during the same observation periods. ERG and histopathological studies showed no differences between the treated and the control fellow eyes (group 5-7) after 4 weeks. 13-cis-RA in SiFO (10 microg ml-1) is as effective as all-trans-RA in SiFO (9 microg 1.5 ml-1) in controlling the incidence of PVR when used for short term retinal tamponade and does not appear to be associated with retinal toxicity.

Animals↗
PubMed1997

Antiproliferative effect of intravitreal alpha-tocopherol and alpha-tocopheryl-acid-succinate in a rabbit model of PVR.

PURPOSE: To evaluate the antiproliferative properties of alpha-tocopherol and alpha-tocopheryl-acid-succinate in a rabbit model of proliferative vitreoretinopathy. METHODS: Fifty-seven rabbits underwent gas-compression vitrectomy and gas/fluid exchange. Group 1 (n = 8): 50 micrograms alpha-tocopherol in 1 ml of 0.5% ethanol in balanced salt solution; Group 2 (n = 8): 50 micrograms alpha-tocopheryl-acid-succinate in 1 ml of 0.5% ethanol in balanced salt solution; Groups 3 (n = 4) and 4 (n = 2): 1 ml 0.5% ethanol in balanced salt solution; Groups 5 (n = 12) and 8 (n = 9): alpha-tocopherol in 1 ml silicone oil (12 mg/ml); Group 6 (n = 9): 1 ml silicone oil; Group 7 (n = 5): 1 ml balanced salt solution. Groups 1-3, and 5-7 also received fibroblasts and platelet-rich plasma injection. Fundus evaluation was performed during a four-week period. The eyes were enucleated for gross examination on day 28. Histopathology was performed on Group 4. RESULTS: Alpha-tocopherol and alpha-tocopheryl-acid-succinate in saline solution delayed development of proliferative vitreoretinopathy, compared to the control group (statistically significant during the first week, Mann Whitney, p < 0.05). The alpha-tocopherol in the silicone-oil group delayed development of proliferative vitreoretinopathy, compared to the silicone-oil group during the second to fourth weeks (no statistically significant difference, p > 0.05). CONCLUSIONS: Alpha-tocopherol and alpha-tocopheryl-acid-succinate in saline solution showed retardation of proliferative vitreoretinopathy traction retinal detachments. In silicone oil, alpha-tocopherol is slowly released and decreases the severity of proliferative vitreoretinopathy, especially during the second week of follow-up.

Animals↗
PubMedDate not supplied

Assessment of the ocular media absorption index.

PURPOSE: To determine a practical method for quantifying in vivo lens absorption by human crystalline, obtaining an index of lens density in our population. METHOD: 62 normal subjects were evaluated in this study (ages ranging from 20 to 71 years). TESTING PROCEDURE: Measurements of dark-adapted scotopic thresholds for 450 nm and 656 nm stimuli were obtained (Tubinger perimeter) in order to determine ocular media absorption. Van Norren and Vos's procedure was used to calculate ocular media absorption transmission loss. Least-squares linear regressions were used to correlate lens density to age. RESULTS: A gradual and approximately linear increase in average lens absorbance was found under 55 years of age. Elder subjects showed a higher increase in this absorbance with higher variability. A correction factor for age-related ocular media absorption was obtained from the calculated curve. The range was approximately 1 to 5 dB. CONCLUSION: Determination of the transmission characteristics of the preretinal media is essential for interpreting threshold sensitivity values. Increase in lens absorption has been shown to be selective for short wavelengths. Due to this fact, a correction factor for the age-related ocular media absorption should be applied to avoid misinterpretation of the Blue-on-Yellow perimetry absolute results. That factor may discriminate sensitivity losses due to changes in the lens from those due to retinal or neuronal dysfunction.

Absorption↗
PubMedDate not supplied

Histological toxicity of grepafloxacin after intravitreal injection.

PURPOSE: To determine the intravitreal levels of grepafloxacin after intravitreal injection of 80 microg and to evaluate the retinal toxicity after intravitreal injection of different doses of grepafloxacin in rabbit eyes. METHODS: Fifteen female New Zealand white rabbits and 15 female pigmented 'Gigantes de España' rabbits were injected with 80 microg of grepafloxacin into the vitreous cavity. The grepafloxacin concentration was determined with HPLC after 2, 4, 8, 12 and 24 h. Eighteen female rabbits (9 New Zealand white rabbits and 9 pigmented 'Gigantes de España' rabbits) were used for a study of toxicity. The rabbits were divided into 6 treatment groups: group 1 (3 pigmented rabbits) received an intravitreal injection of 80 microg of grepafloxacin in 0.1 ml of saline solution, group 2 (3 white rabbits) 80 microg of grepafloxacin in 0.1 ml, group 3 (3 pigmented rabbits) 800 microg of grepafloxacin, group 4 (3 white rabbits) 800 microg of grepafloxacin, group 5 (3 pigmented rabbits) and group 6 (3 white rabbits) 0.1 ml of saline solution. Clinical examination was performed prior to injection and 24 h and 10 days after surgery. The animals were sacrificed 10 days after the injection, and the eyes were enucleated and fixed for histopathology. The specimens were stained with hematoxylin-eosin and toluidine blue. RESULTS: No relevant complications were found during the clinical follow-up. All the eyes showed no abnormalities in the histologic evaluation. CONCLUSION: Grepafloxacin can be considered as a safe alternative for intravitreal injection for the treatment of intraocular infections.

Animals↗
PubMedDate not supplied

Short-wavelength automated perimetry and neuroretinal rim area.

PURPOSE: To determine the correlation between neuroretinal rim area and functional losses detected by short-wavelength automated perimetry (SWAP) in a population of patients with suspected glaucoma. METHODS: Forty-two eyes of 42 ocular hypertensive subjects who met the selection criteria (intraocular pressure greater than 21 mm of Hg and normal conventional visual fields) were studied. A planimetric optic nerve head study was performed, determining the total and sectorized neuroretinal rim areas. SWAP was also done, with a modified Humphrey field analyzer. RESULTS: There were no significant correlations between the neuroretinal rim areas and the global perimetric parameters. However, the correlations between the inferotemporal neuroretinal rim area and some superonasal visual field regions (areas 3 and 4) were significant. CONCLUSIONS: There is a relation in the topography of some visual field areas assessed by SWAP and the inferotemporal neuroretinal rim area, which may play a role in the diagnosis and follow-up of suspected glaucoma.

Adult↗
PubMedDate not supplied

Glaucomatous damage patterns by short-wavelength automated perimetry (SWAP) in glaucoma suspects.

PURPOSE: To determine the glaucomatous visual field damage patterns by short-wavelength automated perimetry (SWAP) in glaucoma suspects, and to compare the frequency of diffuse visual field losses and localized defects. METHODS: 157 eyes of 157 ocular hypertensive subjects who met the selection criteria (intraocular pressure greater than 21 mm Hg and normal standard visual fields) were studied. SWAP was done with a modified Humphrey Field Analyzer. Total (TD) and Pattern Deviation (PD) probability maps were calculated for SWAP. The frequency of abnormlities in the TD and PD were determined, analyzing the visual field loss components. RESULTS: The involvement of the test points was more frequent on the TD plots than on the PD plots for all levels of defects (p< 0.001). The glaucomatous defects also showed certain topographical distribution. CONCLUSIONS: A diffuse sensitivity component of visual field loss was found at all SWAP defect depths in glaucoma suspects.

Adult↗
PubMedDate not supplied

Morphometric study of wound healing in a model of filtering surgery with mitomycin-C.

BACKGROUND: Failure of filtering surgery may be related to excessive wound healing in the surgical area. This effect diminishes with the use of antimetabolic agents. Mitomycin-C (MMC) has proved to be the most effective drug to reduce myofibroblastic proliferation in experimental in vivo and in vitro models. To our knowledge, the objective changes induced by mitomycin-C in the size of wound healing areas have not been investigated. METHODS: Filtering surgery was performed on both eyes of 40 pigmented rabbits. Preoperatively one of the eyes received MMC (0.5 mg/ml), and the fellow eye received balance salt solution as placebo. Animals were killed on days 6, 15, 30 and 58. Microscopic healing areas were measured by digital procedures. The areas of target and fellow control eyes were compared by the Wilcoxon test. RESULTS: This study showed significant differences (p < 0.05) between treated and untreated groups, the healing are a gradually becoming smaller. CONCLUSIONS: Objective methods to quantify the microscopic effects of MMC can be useful to improve our knowledge about the action on this antimetabolite and to enable us to adjust more accurately the timing and dosage when applying the drug in glaucoma filtering surgery.

Animals↗
PubMedDate not supplied

Long-term effects of postoperative subconjunctival injections of mitomycin-C in the rabbit eye.

AIM: Single or multiple subconjunctival injections of mitomycin-C (MMC) may offer one way of establishing the total dosage of MMC more accurately. The method also allows re-applications later postoperatively. In this experimental, randomized prospective study we compared the effects of a single intraoperative application of MMC at the filtering site and a single postoperative subconjunctival injection of the drug. METHODS: The left eyes of 32 pigmented rabbits were divided into two groups. In the first group we applied MMC intraoperatively (IO) with a 4 x 1 mm surgical sponge soaked in a MMC solution (0.5 mg/ml). In the second group we injected 0.4 ml of the same solution subconjunctivally (SC) immediately after (conjunctival) suture. Post-operative evaluation was carried out every day during the first week, then every three days until day 58. Survival analyses were done for intraocular pressure (IOP) and bleb failure. Log-rank tests were used to compare survival differences between the groups. RESULTS: The IO group showed longer survival parameters than the SC group (p < 0.05), both in the control of IOP and as regards blebs. The histological persistence of fistulas was similar. The IO group, however, had a higher incidence of undesirable side effects. CONCLUSIONS: Our findings suggest IO application of MMC is more effective in reducing fibroblast ingrowth. However, subconjunctival application offers certain advantages such as the possibility of repeating the treatment postoperatively and, therefore, using a smaller initial dose.

Animals↗
PubMedDate not supplied

Alpha-tocopherol derivatives and wound healing in an experimental model of filtering surgery.

OBJECTIVE: To describe the effect of alpha-tocopherol derivatives (acetate and acid-succinate) on the histopathological characteristics of the surgical fistula in an experimental model of filtering surgery. MATERIALS AND METHODS: Thirty pigmented rabbits were divided into 3 groups. Twenty-four hours before surgery the animals were injected subconjunctivally with 0.5 mL of solution that depended on the group of treatment: Group 1 (n = 10) 0.75% ethanol in balanced salt solution (BSS); Group 2 (n = 10) 100 microg alph-tocopherol-acetate in 0.75% ethanol in BSS; Group 3 (n = 10) 100 microg alpha-tocopheryl-acid-succinate in 0.75% ethanol in BSS. Histological findings were evaluated 30 days after surgery. RESULTS: The groups treated with alpha-tocopherol derivatives showed a higher percentage of persistence of the fistula and better intraocular pressure (IOP) control. CONCLUSIONS: Alpha-tocopherol derivatives showed antiproliferative properties in this experimental model of filtering surgery.

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