Biomedical subjects

Lenio S Alvarenga

Publications and source records attributed to Lenio S Alvarenga.

5 recordsLinked to original sources

PubMed2005

Ocular rosacea.

Rosacea is a common skin disease that frequently involves the eye. Although the pathogenesis of the disease remains undefined, recent findings suggest that an altered inflammatory response plays an important role in both cutaneous and ocular rosacea. Ocular manifestations include lid and ocular surface alterations. Chronic inflammation can lead to corneal vascularization, which may compromise vision. Treatment of ocular rosacea is aimed at preventing irritation of the ocular surface (e.g., lubricants, lid hygiene) and controlling inflammation with topical and systemic anti-inflammatory drugs. Systemic tetracyclines are the mainstay of treatment. These drugs act multifactorially by decreasing bacterial flora and the expression of matrix metalloproteinases, altering meibum secretion, inhibiting the production of bacterial lipases, and providing an immunomodulatory effect.

Journal Article↗

PubMed2005

Factors modulating p63 expression in cultured limbal epithelial cells.

PURPOSE: The expression pattern of p63, a homologue of the transcription factor p53, and whether it can be used as a corneal epithelial stem cell specific marker remain controversial. We investigated the p63 expression pattern in cultured limbal epithelial cells at different time points in culture, in sparse and confluent cultures, after growth factor starvation, and in single-cell-derived colonies. METHODS: Harvested limbal epithelial cells were plated at 2.5 (sparse) or 5 (dense) x 10 cells/cm and evaluated for p63 expression at day 1, day 4, day 7, after starvation for 72 hours, or in colonies derived from single cells. Expression of corneal lineage specific differentiation marker keratin 3 (K3) was correlated with p63 expression. Results were compared by 1-way ANOVA. RESULTS: More than 85% (85%-90%) of cells expressed p63 on day 1 regardless of cell plating density. On day 4, sparsely plated cultures were subconfluent and demonstrated high p63 expression (87.4%), whereas densely plated cells were confluent and had markedly reduced p63 expression (16.9%). Starvation of subconfluent cultures arrested cell division but did not decrease p63 expression. High-p63-expressing cultures expressed low levels of K3, and this trend was reversed in confluent cultures. Most cells in all colonies derived from single cells expressed p63. CONCLUSIONS: The majority of corneal limbal epithelial cells express p63 in colonies derived from single cells and in subconfluent cultures regardless of time in culture or continuance of cell division. This suggests that p63 expression in culture cannot be used as a marker for stem cells. Significantly reduced number of cells express p63 in confluent cultures, associated with increased cell-cell contact. It is notable that these cells continue to express p63 amid areas of increased cell-cell contact several days after cultures have attained full confluency. This may represent a unique subpopulation of cells that retain proliferative potential in a confluent culture and may be analogous to a subpopulation of stem cells present in vivo.

Adult↗

PubMed2004

The long-term results of keratoplasty in eyes with a glaucoma drainage device.

PURPOSE: To study the outcome of penetrating keratoplasty (PK) in eyes with a glaucoma drainage device (GDD). DESIGN: Retrospective case-controlled study. METHODS: We reviewed all patients who underwent PK from December 1986 to September 2002 at the University of California, Davis (n = 1,974). We identified 33 patients (40 grafts) who were treated with a GDD and followed up for 6 months or more after PK. Graft survival and glaucoma control were compared with grafts in patients without glaucoma (n = 40) and patients with medically controlled glaucoma (n = 17). Kaplan-Meier survival analysis, log rank test, repeated-measures analysis of variance (ANOVA), Fisher exact test, and chi(2) were used in group comparisons. Multivariate analysis was performed using the Cox proportional hazards model. RESULTS: The percentages of clear grafts in the glaucoma drainage device group were 58.5% and 25.8% at 1 and 2 years, respectively. At these time points, glaucoma was controlled in 74.0% and 63.1% of the eyes, respectively. Both medically controlled glaucoma patients and nonglaucomatous patients had higher graft survival percentages at comparable time points. The presence of a GDD was an important factor influencing graft survival (Hazard ratio = 6.8). CONCLUSION: A GDD implant is an independent risk factor for graft failure. Although these devices are effective in controlling intraocular pressure (IOP) in the majority of eyes in the presence of PK, corneal graft clarity is often compromised.

Adolescent↗

PubMed2002

Efficacy and safety of recurrent pterygium surgery using human processed pericardium.

PURPOSE: To investigate the safety and efficacy of human processed pericardium used as an onlay after pterygium excision. METHODS: Twenty-five eyes of 25 patients (11 female, 14 male) with recurrent pterygium were included in this study. The median age was 50 years (range 24-89 years). Twenty-eight percent of the eyes previously had been operated on two or more times. The mean follow-up was 9.4 months (+/- 2.1 months, range 8-15 months). Following bare-sclera surgical removal of recurrent pterygium, a patch of processed human pericardium was sutured to cover the area of excision. The pericardium was not covered with conjunctiva, nor were adjuvant radiation or antimetabolite administered. All patients were treated with a combination of dexamethasone 0.1% / chloramphenicol drops three times per day for 1 month. Ketorolac tromethamine 0.5% three times per day was added to this regimen after complete corneal reepithelialization. RESULTS: Recurrence (any growth >1 mm onto the cornea) was detected in 12 patients (48%). The mean time of recurrence was 4.1 +/- 1.7 months. Three patients (12.0%) presented a regrowth of fibrovascular tissue not reaching 1 mm of the cornea. Pyogenic granulomas occurred in three patients, and all of them required surgical excision. Corneal thinning was present in one patient and was treated with a therapeutic contact lens and artificial tears with complete resolution and vascularization of the thinned area. No decrease in visual acuity was observed in any patient. CONCLUSIONS: The use of processed pericardium in pterygium surgery is a safe procedure but is associated with a relatively high rate of recurrence. It should only be considered as an option in managing recurrent pterygium when conjunctival autografting is not an available alternative.

Adult↗

PubMedDate not supplied

Glycomics analyses of tear fluid for the diagnostic detection of ocular rosacea.

A Glycomics approach to detect disease is illustrated in the analyses of human tear fluid for rosacea. The diagnosis of ocular rosacea is particularly challenging in a subgroup of patients that do not present with typical facial skin findings but have ocular signs and symptoms. Indeed, up to 90% of patients with ocular rosacea may have neither obvious roseatic skin changes nor a previous diagnosis of rosacea. Tear fluid was collected from 37 subjects (21 controls and 16 patients with ocular rosacea) after conjunctival stimulation with filter (Schirmer) paper. O-linked oligosaccharides were released from tear fluid by beta-elimination and then purified using solid-phase extraction. Mass spectra were recorded on an external source HiResMALDI with a 7.0 T magnet. Mass spectra were obtained in both the positive and negative modes. However, signals were stronger in the negative mode. Tear fluid samples from rosacea patients yielded distinctive clusters of peaks that extend to higher masses. Patients with rosacea presented several oligomeric series that were not found in the controls. To discriminate the ocular rosacea cases from the normal controls, the sum of absolute intensities of 13 series corresponding to nearly 50 identified mass spectrum peaks was used. Thirty-six out of the 37 samples were correctly classified. This yields a sensitivity of 100% (95% CI 79.5-100) and specificity of 95.2% (95% CI 76.2-99.9). The high abundance of oligosaccharides in the tear fluid of patients with rosacea may lead to an objective diagnostic marker for the disease.

Biomarkers↗