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Biomedical subjects

H M Boisjoly

Publications and source records attributed to H M Boisjoly.

At least 19 recordsLinked to original sources
PubMed2000

Dorzolamide and corneal recovery from edema in patients with glaucoma or ocular hypertension.

PURPOSE: To investigate whether dorzolamide alters corneal hydration control in patients with glaucoma or ocular hypertension. METHODS: Pachymetry, tonometry, and endothelial cell density were measured by a masked observer in 19 subjects with bilateral glaucoma or ocular hypertension. They were treated with 2% dorzolamide in one eye, and with saline in the other, before wearing contact lenses under patched eyes. Corneal thickness, measured each 30 minutes up to 4.5 hours after contact lens removal, enabled estimation of percentage recovery per hour and time for 95% of corneal thickness recovery for both eyes. Seven patients repeated this test after 1 year of dorzolamide use, and their results were compared with those of the preceding year. RESULTS: After induction of hypoxic corneal edema, there was no significant difference between paired corneas in swelling levels (60.0+/-11.8 and 59.8+/-12.9 microm) (P = .94), time to 95% recovery (440.6+/-255.8 and 445.4+/-186.7 minutes) (P = .93), and percentage recovery per hour (38.1%+/-10.9% and 36.1%+/-9.6%) (P = .40). Subjects followed up after 1 year of dorzolamide use did not differ significantly in values of endothelial cell density, percentage recovery per hour, or time to 95% recovery from those obtained a year before. One subject developed persistent corneal edema after his stress test in the eye treated with dorzolamide. CONCLUSION: There is no significant difference in the recovery from induced corneal edema after either a short-term or 1-year use of dorzolamide in patients with glaucoma or ocular hypertension with a normal corneal endothelium. One patient had persistent corneal edema after the stress test was performed on the dorzolamide-treated eye.

Aged↗
PubMed1998

Role of presensitization and donor-recipient crossmatching in corneal graft outcome.

PURPOSE: A positive donor-recipient crossmatch (CM) due to preexisting recipient lymphocytotoxic antibodies is known to be an important factor in allograft failure in the majority of organ transplantations. However, the effect of positive CM on corneal graft outcome is less known. METHOD: Between 1982 and 1994, CM was performed by the microlymphocytotoxicity method using donor lymphocytes and recipient pretransplant serum in 759 consecutive corneal transplantations (maximal follow-up, 36 months). Patients were evaluated regarding the type of allospecificity of antibodies involved and their role on corneal graft outcome (rejection and failure). RESULTS: A positive CM was found in 61 patients (8%) and a negative CM in 698 patients (92%). The positive and negative CM groups had similar graft rejection rates at 36 months. Patients with a positive CM due to antibodies directed against donor human leukocyte antigen (HLA) (as defined on the basis of private and public or CREG HLA allele specificities) did not have an increased risk of rejection. However, patients with positive CM and presensitization (previous graft or rejection history) had a statistically significant increase in risk of corneal endothelial rejection. CONCLUSION: This study shows that donor-recipient CM could be a useful procedure for the selection of recipients for corneal transplantation in patients presensitized by anterior graft or previous corneal rejection.

Adult↗
PubMed1998

Screening for diabetic retinopathy. Do family physicians know the Canadian guidelines?

OBJECTIVE: To assess whether family physicians and family medicine residents know what the Canadian guidelines for screening for diabetic retinopathy are, and to assess whether they believe they can perform this screening. DESIGN: Mailed survey with two mailed reminders. PARTICIPANTS: All general practitioners (N = 1038) listed in two health catchment areas, Québec and Chaudière-Appalaches administrative regions in the province of Québec, and all family medicine residents (N = 125) at Laval University Medical School. Response rate was 62% among general practitioners and 77% among residents. MAIN OUTCOME MEASURES: Knowledge of screening guidelines for diabetic retinopathy in type I and type II diabetes, including timing of the initial screening examination, risk factors, natural history, and treatment of ocular complications; and perception of ability to screen for diabetic retinopathy. RESULTS: Among GPs, 80% of respondents correctly chose the statement with the current guideline for first screening for diabetic retinopathy to be performed shortly after diagnosis of type II diabetes. Only 13% of respondents were familiar with the guideline for first screening 5 years after diagnosis of type I diabetes. Agreement with other correct guideline statements was also low. Overall, residents had higher scores than GPs. Most respondents were not confident in the accuracy of their eye examinations. CONCLUSIONS: General practitioners and family medicine residents have varying levels of knowledge about the Canadian guidelines for screening for diabetic retinopathy. These results will be useful in designing and improving educational programs for GPs in diabetic retinopathy screening.

Adult↗
PubMed1997

Should we patch corneal erosions?

OBJECTIVE: To study the effect of patching on the speed of reepithelialization, slit-lamp signs of epithelial wound healing, and patient discomfort following a corneal abrasion. METHODS: Forty-eight eyes of 46 patients with corneal erosion sparing Bowman membrane were randomized into 2 groups: with or without patching. Slit-lamp examination and photographs of the fluorescein-stained cornea were performed on a daily basis until reepithelialization was complete. Photographs were analyzed using computer-assisted planimetry. RESULTS: No statistically significant difference was found between patched (n = 25) and nonpatched (n = 22) eyes for the mean size of the initial erosion (patched eyes, 23.7 mm2; nonpatched eyes, 18.9 mm2; P = .42), linear speed of reepithelialization (reduction over time of the radius of the largest circle included in the erosion: patched eyes, 0.0375 mm/h; nonpatched eyes, 0.0353 mm/h; P = .78), and surface speed of reepithelialization (reduction over time of the erosion area: patched eyes, 0.6510 mm2/h; nonpatched eyes, 0.5657 mm2/h; P = .60). The power to detect a 12-hour delay of epithelial closure was 95%. There were no significant differences between the 2 groups for pain, analgesia, insomnia, aspect of the epithelial border, intensity and duration of stromal edema, Descemet folds, anterior uveitis, and filaments. CONCLUSIONS: Patching a corneal erosion does not significantly accelerate reepithelialization and does not alter the epithelial wound healing pattern. It does not reduce the incidence and severity of inflammation nor relieve pain when compared with treatment without patching.

Adult↗
PubMed1997

Role of ABO and Lewis blood group antigens in donor-recipient compatibility of corneal transplantation rejection.

PURPOSE: There are conflicting results regarding the role of human leukocyte antigen (HLA) matching and ABO compatibility in corneal graft rejection for low- and high-risk patients. Lewis blood group antigens could be an important histocompatibility system. Beneficial effects of Lewis antigens matching have been reported in renal transplantation, but its effect is still unknown in corneal allografting. METHODS: Between 1987 and 1993, ABO, Lewis and HLA phenotypes were determined in 697 consecutive grafts of corneal transplantations. The effect of Lewis matching on corneal endothelial rejection was evaluated over a 3-year period. Data analysis was done by plotting survival curves with the Kaplan-Meier method for survivorship data and performing statistical analysis with the log-rank test (Mantel-Haenszel test) for curve comparison. RESULTS: In vascularized recipients, the ABO, Lewis, and HLA systems did not influence the graft outcome. However, for the unvascularized recipients, the endothelial 3-year rejection rate was significantly lower for both Lewis compatible patients (84% vs. 68%; log rank = 0.03) and HLA compatible patients (86% vs 72%; log rank = 0.001), but not for the ABO-matched patients (82% vs. 79%; log rank = 0.56). CONCLUSIONS: The authors' study suggests that Lewis antigens and HLA matching could positively influence corneal graft survival for the unvascularized recipients, but it did not seem to have any effect in vascularized recipients.

ABO Blood-Group System↗
PubMed1997

Corneal endothelial cell density in glaucoma.

PURPOSE: We studied corneal endothelial cell density in patients with glaucoma. METHODS: One hundred two patients with glaucoma were compared with 52 patients without glaucoma of the same age group. Exclusion criteria included history of either corneal disease, ocular inflammation, trauma, or surgery other than peripheral iridectomy. The following data were extracted from the patient files: glaucoma type and duration, laser treatments, glaucoma medications, and documented intraocular pressure (IOP) measurements. Specular microscopies were performed on central corneas, endothelial images were analyzed by computerized planimetry, and cell counts were calculated. RESULTS: Corneal endothelial cell counts were significantly lower in patients with glaucoma (2,154 +/- 419 cells/mm2) than in controls (2,560 +/- 360 cells/mm2; t test, p < 0.0001). In the glaucoma group, cell counts were inversely proportional to the means of IOPs. Patients receiving three or four glaucoma medications had lower cell counts than those receiving one or two medications. Cell counts were significantly lower both in primary angle-closure glaucoma and in primary open-angle glaucoma. CONCLUSION: This study suggests that patients with glaucoma may have lower corneal endothelial cell density than those without glaucoma of the same age group. The proposed mechanisms are direct damage from IOP, congenital alteration of the corneal endothelium in patients with glaucoma, glaucoma medication toxicity, or a combination of these.

Aged↗
PubMed1996

Anterior stromal punctures for bullous keratopathy.

OBJECTIVE: To evaluate the therapeutic effects of anterior stromal punctures (ASP) in patients with bullous keratopathy (BK). PATIENTS AND METHODS: Twenty-seven patients awaiting penetrating keratoplasty with a diagnosis of BK were examined. They were seen before treatment with ASP and 1, 4, and 12 weeks after treatment. The examination included slit-lamp examination, photography of the cornea, ultrasonic pachymetry, central esthesiometry, and pneumotonometry. Subjective evaluations of pain, discomfort, and photophobia were also done using a visual scale model. Photographs were analyzed by computer-assisted planimetry and used to measure the corneal surface covered by bullae and microcysts. Pretreatment and posttreatment values (mean +/- SEM) were compared using the Student paired t test. RESULTS: At 3 months, a significant reduction in pain was noted. A decrease in the mean corneal surface covered by bullae (BKPreASP = 2733 +/- 553 microns2; BK3mo = 1006 +/- 356 microns2, P = .004) was observed. A decrease in the esthesiometry (E) measurement (EPreASP = 3.5 +/- 0.4 cm; E3mo = 1.3 +/- 0.3 cm, P < .001), an increase in corneal thickness ([CT] CTPreASP = 869 +/- 24 microns; CT3mo = 902 +/- 21 microns, P < .001), and a decrease in the number of quadrants through which iris (I) details could be seen (IPreASP = 1.7 +/- 0.3; I3mo = 1.2 +/- 0.3, P = .015) were also noted. These findings corroborate the clinical observation of increased subepithelial fibrosis following ASP. CONCLUSIONS: Anterior stromal punctures reduce bullae formation and alleviate pain in patients with BK, and they constitute a valuable alternative to penetrating keratoplasty should surgery be delayed or contraindicated.

Adult↗
PubMed1994

Mechanical properties of the rabbit cornea during wound healing after treatment with epidermal growth factor.

To determine whether epidermal growth factor (EGF) accelerates the healing of corneal tissue, we measured the tensile strength, ductility (total deformation at rupture) and toughness of 60 rabbit corneas with 7-mm perforating wounds after topical treatment with EGF or saline for 8, 13 or 23 days. The three mechanical properties were measured using corneal strips mounted on an Instron tensometer. A traction speed of 5 cm/min was chosen from speed-response curves for the three measures of interest. Since the values for eyes of a single rabbit were correlated, we used the data for one eye, selected at random, from each animal in the data analysis. EGF enhanced tensile strength (p = 0.003) and toughness (p = 0.03) of corneas without reducing ductility. The difference in tensile strength and toughness between EGF- and saline-treated corneas was more striking at 8 and 13 days than at 23 days. Histologic studies at 13 and 23 days supported these observations: at 13 days the healing process was more advanced in EGF-treated corneas, whereas at 23 days no histologic differences were noted. We conclude that EGF accelerates wound healing in rabbit corneas with perforating wounds without reducing ductility of the corneal tissue.

Administration, Topical↗
PubMed1993

Effects of EGF, IL-1 and their combination on in vitro corneal epithelial wound closure and cell chemotaxis.

We investigated the effects of EGF, IL-1 and their combination on closure of wounds inflicted on rabbit corneal epithelial cell cultures and on migration of these cells in microchemotaxis chambers. In vitro corneal epithelial wound closure depended on the applied concentrations of EGF or IL-1. Twenty-four hours after wounding, the smallest wounds were obtained with 50 ng ml-1 of EGF and 1 ng ml-1 of IL-1, respectively. The effect on wound closure of combinations of EGF and IL-1 was additive even at concentrations that were optimal for each growth factor when applied alone. We found that EGF increases the chemotactic migration of rabbit corneal epithelial cells. Cell chemotaxis depended both on the concentration of EGF and on the number of cells applied in the assay. This response to EGF was seen at concentrations that were effective in the wound closure assay. The magnitude of the chemotactic migration response was much smaller with IL-1 than with EGF. Similarly to the observations on wound closure, the effect on cell chemotaxis of combinations of EGF and IL-1 was additive. The ability of EGF, and EGF/IL-1 combinations to modulate corneal epithelial cell chemotactic migration supports migration as a possible biological mechanism of the acceleration of corneal epithelium wound closure by these drugs.

Animals↗
PubMed1993

Risk factors of corneal graft failure.

PURPOSE: To measure the association between potential risk factors and corneal graft failure. Two failure outcomes are compared: those with and those without a prior immune allograft reaction. METHODS: Based on a single-center observational study design, 539 adult recipients of a corneal graft were followed for a median time of 30 months. Survival analysis was carried out. RESULTS: Eighty-two graft failures were recorded. Of 82 failures, 53 (65%) were not preceded by an immune allograft reaction. Presence of blood vessels in the recipient cornea was associated with a twofold increase in risk for both failure outcomes. Three factors increased the risk of failure without an immune reaction: prior glaucoma or uveitis (adjusted relative risk estimate = 3.1), vitreous surgery with the graft (adjusted relative risk estimate = 2.0), and a repeat graft in the study eye (adjusted relative risk estimate = 2.0). Conversely, large graft wound size (adjusted relative risk estimate = 2.0). Conversely, large graft wound size (adjusted relative risk estimate = 2.9) and human leukocyte antigen (HLA)-A, -B incompatibility (adjusted relative risk estimate = 2.2) were associated with failures that followed an immune reaction. CONCLUSION: In this study, the authors support the clinical impression that corneal graft failures with and without a prior immune reaction are distinct phenomena. Enhanced surveillance in recipients with glaucoma and early intensive treatment of allograft reactions are recommended to improve the outcome of corneal grafts.

Cataract Extraction↗
PubMed1992

Pretransplant and posttransplant antibodies in human corneal transplantation.

The purpose of this study was to measure the association between antibody formation and endothelial corneal allograft reactions in 533 consecutive corneal graft recipients. The median follow-up time of these recipients was 732 days. Pretransplant panel-reactive antibodies were not found to be associated with endothelial corneal allograft reactions. Out of 533 recipients, 239 developed posttransplant antibodies during the course of this study. The formation of posttransplant antibodies was frequent in recipients with pretransplant antibodies and in HLA-A,-B-incompatible recipients. Posttransplant antibodies most often appeared within the first six months after transplantation whereas endothelial allograft reactions most often occurred later. Out of 65 recipients who developed PPRA and underwent an allograft reaction, 53 had a PPRA peak prior to, or at about the time of, the allograft reaction. Corneal allograft reaction events diagnosed during the second and third year after surgery were correlated with PPRA formation during the first year after grafting. The 36-month reaction-free survival rate of transplants was estimated at 72% in recipients with PPRA compared with 86% in recipients without PPRA (log rank P value = 0.002). Furthermore, posttransplant antibody formation altered the outcome of corneal allografts in both HLA-A and -B-compatible and -incompatible recipients. These findings suggest that posttransplant antibody development represents a high risk of endothelial corneal allograft reactions.

Antibodies↗
PubMed1991

Topical autologous fibronectin in patients with recurrent corneal epithelial defects.

We designed a clinical trial to evaluate the effect of topical fibronectin (an adhesive protein) for prevention of recurrent corneal epithelial defects. Fifteen eyes (11 patients) with 2 documented epithelial defects within 12 weeks were included. Purity and biological activity of the prepared solutions of autologous plasma fibronectin were confirmed by sodium dodecyl-sulfate polyacrylamide gel electrophoresis and gelatin binding affinity, respectively. According to randomization, fibronectin or saline was given 5 times per day for 11 weeks to 1 eye of 11 patients. Eyes of 4 patients with bilateral disease were paired, 1 eye receiving fibronectin and the other saline. We examined the patients weekly. The following recurrence parameters were retained for analysis: number of weeks with an epithelial defect, area under recurrence curves, and number of weeks with discomfort. The randomized and paired data analyses suggest that topical autologous plasma fibronectin does not prevent recurrent corneal epithelial defects. We describe a patient who received two treatment courses bilaterally, each eye crossing over to the alternate medication after a first treatment course. The response to treatment of each eye appeared unassociated to the medication.

Administration, Topical↗
PubMed1990

Topical fibronectin and aprotinin for keratectomy wound healing in rabbits.

We evaluated the effect of fibronectin (an adhesive protein) and aprotinin (a protease inhibitor) as single or combined topical therapies for primary healing and prevention of recurrent corneal epithelial defects in the rabbit keratectomy wound model. The biological activity of the prepared solutions of rabbit plasma fibronectin (0.6 g/L) was suggested by in vitro assays of rabbit corneal epithelial cell adhesion and gelatin-binding affinity. In the first experiment, we compared fibronectin, albumin (a control nonadhesive protein), and saline. In the second and third experiments, fibronectin supplemented with aprotinin, aprotinin alone, and saline were compared; aprotinin was used at concentrations of 40 and 1000 kallikrein inactivating units (KIU) per mililiter. Our results suggest that topical fibronectin, 0.6 g/L, as well as aprotinin at 40- and 1000-KIU/mL concentrations, given alone or in combination, neither promote corneal epithelial wound healing nor prevent recurrent corneal epithelial defects in rabbit keratectomy wounds.

Administration, Topical↗
PubMed1990

Long-term culture and characterization of human limbal microvascular endothelial cells.

Human limbal explants obtained from 44 eyebank donors were cultured in medium 199 supplemented with 20% fetal bovine serum, vascular endothelial cell growth supplement and heparin. Cells grew abundantly out of the explants. They initially formed a 'cobblestone' patterned monolayer but later exhibited an elongated morphology with growth in parallel bundles. These cells could be passaged at least nine times and were identified throughout the consecutive passages as microvascular endothelial cells by the expression of factor VIII-related antigen, laminin and of the H determinant of ABO blood groups. As expected from vascular endothelial cells, flow cytometric analysis demonstrated a strong expression of class I histocompatibility antigens and a weaker expression of class II antigens. Class II antigen expression was enhanced by culturing the cells in the presence of immune interferon. These cells produced immunoreactive interleukin-1, mainly of the alpha type, under endotoxin stimulation. Limbal microvascular cells could be useful to study corneal angiogenesis. Furthermore, long-term culture of limbal cadaveric tissue can potentially be used to characterize donor-specific immunologic responses in corneal graft recipients.

ABO Blood-Group System↗
PubMed1990

Association between corneal allograft reactions and HLA compatibility.

The purpose of this follow-up study is to measure the association between corneal allograft reactions and donor-recipient HLA-A and HLA-B compatibility. Four hundred thirty-eight consecutive adult recipients of corneal grafts with known donor-recipient HLA matching were observed for allograft reactions and failures. Most of the recipients under observation (91%) were well matched for HLA-DR. Of 438 recipients, 158 (36%) completed a 3-year follow-up. Three factors were associated with endothelial allograft reactions: 2 to 4+ corneal vascularization (relative risk, 2.2; P = 0.0006), two mismatched antigens at either the HLA-A or HLA-B locus (relative risk, 2.1; P = 0.0009), and recipient wound size of 8 mm or greater (relative risk, 1.5; P = 0.05). Unexpectedly, a strong association between endothelial allograft reactions and HLA-A or HLA-B incompatibility was found in low-risk recipients defined as unvascularized recipients of a small graft (relative risk, 3.2; P = 0.004). A larger sample size is required to determine if HLA matching offers a solution for recipients with corneal vascularization.

Adolescent↗
PubMed1990

11p13 deletion, Wilms' tumour, and aniridia: unusual genetic, non-ocular and ocular features of three cases.

Three cases of Wilms' tumour and sporadic aniridia were followed up for periods ranging from 32 months to seven years. All had a deletion of the short arm of the eleventh chromosome 11p13, including one case with mosaicism, a cytogenetic feature that has not been previously described in the Wilms' tumour and sporadic aniridia association. Unusual non-ocular features found in all patients included tracheomalacia and delayed closure of the anterior fontanelle. In two cases tracheomalacia was responsible for respiratory distress after general anaesthesia. Wilms' tumour developed bilaterally in one patient and on the isthmus of a horseshoe kidney in another patient. In addition to the more commonly observed ocular features the presence of a corneal pannus was noted before 38 months of age in all patients and as early as 17 months in one case. An iridocorneal adherence with an overlying corneal opacity (presumably related to abnormal developmental cleavage of the anterior segment) was noted in one eye only of the mosaicism case.

Anesthesia, General↗
PubMed1990

Comparison of prednisolone acetate and indomethacin for maintaining mydriasis during cataract surgery.

Preoperative topical nonsteroidal anti-inflammatory drugs such as flurbiprofen and indomethacin have been found to maintain mydriasis during cataract surgery. Steroidal anti-inflammatory drugs are commonly used to treat postoperative inflammation, but their effect on the maintenance of intraoperative mydriasis is unknown. Forty-six patients admitted for elective cataract surgery were randomly assigned to one of three treatment groups and received 1% prednisolone acetate, 1% indomethacin or artificial tears four times before surgery, in addition to standardized preoperative dilating drops and intraoperative epinephrine. Pupillary diameter was measured and the time interval noted five times during the surgery. During surgery the indomethacin group lost significantly less mydriasis than the control group. The mydriasis losses of the prednisolone acetate group were between those of the indomethacin and control groups, but these differences did not reach significance. We conclude that prednisolone acetate is less effective than indomethacin for maintaining mydriasis during cataract surgery.

Adult↗