Biomedical subjects

Francisco C Figueiredo

Publications and source records attributed to Francisco C Figueiredo.

6 recordsLinked to original sources

PubMed2006

Differences in leukocyte phenotype and interferon-gamma expression in stroma and endothelium during corneal graft rejection.

Critical to the success of human corneal transplants is prevention of corneal endothelial rejection, yet little is known about the endothelial infiltrate. To examine the endothelium, a method for removal and processing this layer as a flat sheet was used and the infiltrate was compared with stroma and epithelium. LEW or PVG strain rat corneas were transplanted to PVG strain recipients. Clinical changes after transplantation were monitored by slit lamp and animals sacrificed at a range of time points during rejection. Clinically defined rejection, accompanied by an epithelial rejection line and endothelial cell infiltration, occurred between days 10 and 15. There was some infiltration of leukocytes in the stroma of isografts at these time points, but significantly more in allografts (p<0.003 for all subsets). There was no infiltration of isograft endothelium at any time and no infiltration of allograft endothelium on day 10. On day 15, there were similar numbers of all major subsets except B cells in the stroma, while on the endothelium macrophages, MHC class II(+) cells and CD8(+) cells predominated (p<0.001 CD4(+) vs CD8(+) cells). T cells and NK cells predominated in the epithelial rejection line. While TNF-alpha and IFN-gamma-producing cells were numerous in stroma and epithelium, no IFN-gamma-producing cells were found on endothelium. Distinct differences in infiltrative profile within layers of the cornea suggest that the mechanisms of rejection may also differ. The restricted endothelial cell profile and lack of IFN-gamma suggests that the anti-endothelial response may be modulated by the anterior chamber environment.

Animals↗

PubMed2006

Utility assessment to measure the impact of dry eye disease.

Utility assessment is a formal method for quantifying and understanding the relative impact of a given health state or disease on patients. In this article, methodology of utility assessment is explained and illustrated, and results of an original study are reported. The study was conducted to determine utility values (patient preferences) associated with dry eye disease and compare them to other disease utilities, as well as to compare patient and physician assessments of disease. Forty-four patients in the United Kingdom with moderate to severe dry eye were surveyed via interactive utility assessment software. Utility values were measured by the Time Trade-Off (TTO) and Standard Gamble (SG) methods and adjusted to scores from 1.0=perfect health to 0.0=death. Patients reported utilities for: self-reported current dry eye status, self-reported current comorbidities, various dry eye severities, and binocular and monocular painful blindness. Patient's dry eye severity was independently classified by patient and physician assessments. Correlation analyses (Pearson) were performed between patients' current dry eye utilities and the physician-assessed severity. Agreement between self-reported and physician-reported patient severity was analyzed (Kappa). Patients reported higher utilities for their current dry eye condition than for monocular and binocular blindness (SG:0.84>0.60>0.51; TTO:0.67>0.43>0.38). Using TTO, the mean score for asymptomatic dry eye (0.68) was similar to that for "some physical and role limitations with occasional pain" and severe dry eye requiring surgery scored (0.56) similarly to hospital dialysis (0.56-0.59) and severe angina (0.5). Utilities described for scenarios of dry eye severity levels were slightly higher for patients self-reported as mild-to-moderate versus those self-reported as severe. For current dry eye condition, mean utilities for these groups were 0.72 for self-reported mild-to-moderate and 0.61 for self-reported severe. Utilities for dry eye were in the range of conditions accepted as lowering health utilities. Severe dry eye utilities were similar to those reported for dialysis and severe angina, highlighting the impact of dry eye disease on patients.

Attitude to Health↗

PubMed2006

Corneal first surface wavefront aberrations before and after pterygium surgery.

PURPOSE: To determine the higher order aberrations at the corneal first surface before and after surgery for pterygium. METHODS: Data were drawn from a longitudinal study of patients undergoing pterygium excision at Royal Victoria Infirmary, Newcastle upon Tyne, England between September 1998 and May 2004. Corneal topography was taken with the TMS-2 Topographic Modeling System (Computed Anatomy Corp) prior to and 6 months after surgery, exported to VOLPro software v7.08 (Sarver & Associates), and wavefront aberrations were derived for a 5.0-mm pupil using a 10th order Zernike polynomial expansion. Pre- to postoperative changes were assessed for significance using analyses of variance, and the relative risk of significant postoperative aberrations by pterygium size was determined. RESULTS: Satisfactory corneal topography was available on 67 eyes (mean age 53.8 +/- 16.7 years [range: 25-86 years]). The root-mean-square (RMS) fit error in preoperative eyes was 0.15 +/- 0.10 microm. Preoperatively, the total higher order RMS wavefront aberration was 0.94 +/- 0.83 microm. All Zernike modes were elevated, with trefoil being the major contributor 0.52 +/- 0.50 microm. Pterygium excision significantly reduced wavefront aberrations across all modes and orders (F(1, 129) = 6.7 to 22.6, P < .01): total higher order RMSpostop 0.45 +/- 0.35 microm. Cases with visually significant postoperative aberrations occurred and were more likely with larger pterygia: relative risk compared to pterygia 1.0 to 1.9 mm was 1.3 for 2.0 to 2.9 mm, 8.5 for 3.0 to 3.9 mm, 13.3 for 4.0 to 4.9 mm, and 10.2 for 5.0 to 5.9 mm. CONCLUSIONS: Zernike polynomial fitting well describes wavefront aberrations in eyes with pterygia. Pterygia are associated with wavefront aberrations, especially trefoil, but these were largely eliminated by surgery. Earlier excision of pterygia reduces the likelihood of significant residual aberrations.

Adult↗

PubMed2005

Unusual cause of visual symptoms after bilateral laser in situ keratomileusis.

We present a case involving a serious systemic cause of visual symptoms after successful bilateral laser in situ keratomileusis. There were no signs in the anterior segment to explain the visual symptoms. Ancillary tests and investigations confirmed a pituitary tumor, which was removed. We recommend comprehensive ophthalmological examination and full investigation of symptoms in all patients before and after laser treatment.

Adenoma↗

PubMed2005

Opinions on risk factors and management of corneal graft rejection in the United kingdom.

PURPOSE: To determine the opinions regarding risk factors and practice preferences for corneal graft rejection by members of the Bowman Club (UK) and to compare them with those of members of the Castroviejo Society (USA). METHODS: A questionnaire was sent in 1999 to members of the Bowman Club (UK), who were responsible for two thirds of all corneal grafts undertaken annually. The survey included 8 questions identical to those given to members of the Castroviejo Society (USA) in a survey carried out in 1989. RESULTS: Thirty-six out of 40 surgeons replied. Factors considered by respondents to be high risk for corneal graft rejection were previous corneal graft rejection in the operated eye (97%), significant corneal vessels (97%), and previous herpetic eye disease (94%). The preferred routine preoperative treatment in "high-risk" patients included no treatment (47%), topical corticosteroids (33%), and oral prednisolone (22%). In postoperative "high-risk" patients, 100% of surgeons used topical and 42% used oral corticosteroids. Immune suppression agents were used by 44% of respondents, the majority (92%) using cyclosporine A. In previous herpes simplex patients, 47% of surgeons used oral and 14% used topical antivirals preoperatively, whereas 75% used oral and 47% used topical postoperatively. CONCLUSION: This study documents the perceived risk factors and management of corneal graft rejection by corneal surgeons in the UK. It showed wide variation in practice preferences, allowing individual surgeons a comparison with peer practice. It highlights the need for greater use of postoperative antiviral prophylaxis in the presence of previous herpetic corneal pathology.

Administration, Oral↗

PubMed2002

Corneal epithelial rejection in the rat.

PURPOSE: To investigate clinical and histologic changes in the epithelium during corneal graft rejection in the rat. METHODS: LEW (RT1(l)) or PVG (RT1(c)) strain corneas were transplanted to PVG strain recipients and examined by slit lamp for clinical signs of rejection. Recipients were killed, and corneal epithelial sheets were removed and examined by adenosine diphosphatase (ADPase) staining for Langerhans cells (LC) and by immunohistology for leukocytes and adhesion molecules (T cells, macrophages, granulocytes, major histocompatibility complex [MHC] class II, CD2 and CD54 intercellular adhesion molecule [ICAM]-1) at a range of time points before, during, and after rejection, depending on the cell type sought. Normal and contralateral eyes were examined for ADPase(+) and MHC class II(+) cells. RESULTS: Clinical rejection, as defined by stromal opacity, occurred between days 10 and 15 after transplantation. In 94% of allografts, a curved clinical epithelial rejection line was observed in which ADPase(+)/MHC class II(+), CD4(+), or CD8(+) T cells were identified. There were significantly more infiltrating cells of all types in epithelia of allografts than in those of isografts. The most numerous cells were CD4(+) and CD8(+) T cells, suggesting preferential migration of these cells into the epithelium from underlying layers. Expression of MHC class II and ICAM-1 was induced on epithelial cells. CONCLUSIONS: Epithelial rejection in rats is clinically similar to that in humans and occurs simultaneously with stromal infiltration. It may be mediated by T cells rather than macrophages. In isolation, its recognition in humans may be a useful indication that the patient is at high risk of endothelial rejection.

Animals↗