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Biomedical subjects

L Laroche

Publications and source records attributed to L Laroche.

At least 109 records · Page 6Linked to original sources
PubMed1999

[Effect of sodium hyaluronate administered at the end of penetrating keratoplasty on reepithelialization of the graft].

PURPOSE: To investigate the effect of sodium hyaluronate on reepithelialization time after penetrating keratoplaty. METHODS: We prospectly studied 56 consecutive penetrating keratoplasties. One group of patients (n = 22) received dexamethasone ointment at the end of surgery. The second group (n = 34) received sodium hyaluronate and topical dexamethasone. Postoperative reepithelialization time and graft central thickness were recorded. RESULTS: There was no statistical difference between both groups for epithelialization (4.6 + 3.2 days in the hyaluronate group and 4.4 + 2.3 days in the dexamathasone group) and for graft thickness at day one (710 + 85 microns for the former group and 713 + 84 microns for the latter group) and at day of reepithelialization (663 + 80 microns for the former group and 703 + 99 microns for the latter group). The epithelium aspect was different at the first postoperative day between both groups. CONCLUSION: The use of sodium hyaluronate at the end of penetrating keratoplasty improves the graft epithelium aspect at the first postoperative day, but it does not influence reepithelialization time. Further studies are needed to investigate the mechanism of sodium hyaluronate effect on corneal epithelium.

Aged↗
PubMed1999

[Comparison of EyeSys videokeratoscope algorithms in the evaluation of idiopathic and postoperative astigmatism].

PURPOSE: To compare the accuracy and reproducibility of the Eye Sys videokeratoscope algorithms for analyzing idiopathic and surgery-induced astigmatism analysis. METHODS: Refractive astigmatism, videokeratoscopy (axial, tangential and refractive power), autorefractometry, autokeratometry, and keratometry were recorded in 20 patients with idiopathic astigmatism, 40 patients who had undergone cataract surgery and 40 patients who had undergone penetrating keratoplasty. For each eye, 2 successive videokeratoscopy were recorded. RESULTS: Both cylinder and axis provided by the tangential algorithm are significantly less reproducible than the cylinder and axis provided by the axial and refractive algorithms (P < 0.001). Cylinders provided by the axial and refractive algorithms showed a stronger correlation with subjective cylinder (rs > 0.89; p < 0.001) than the cylinder provided by the tangential algorithm (rs = 0.66; p < 0.001). Both keratometric axis and autokeratometric axis showed the strongest correlation with subjective axis (rs > 0.92; p < 0.001). The accuracy and reproducibility were higher for the topographic "bow tie" patterns than for the other topographic patterns. CONCLUSION: The axial and refractive algorithms of the Eye Sys videokeratoscope are more accurate and reproducible than the tangential algorithm for analyzing idiopathic or surgery-induced astigmatism.

Algorithms↗
PubMed1998

Microbiologic study of organ-cultured donor corneas.

BACKGROUND: Our purpose was to evaluate the sterility of organ-cultured human donor corneas at the time of surgery. METHODS: We studied 603 organ-cultured corneas. Of these 603 corneas, 409 (68%) were grafted and 69 (11%) were contaminated during storage. RESULTS: Contamination during preservation was either bacterial (65%) or fungal (35%). None of the tested antibiotics were effective against all of the 45 isolated bacteria. The risk of contamination decreased with death-to-organ culture time (P=0.008) and was higher for corneas excised in situ than for those enucleated (P=0.02). Corneoscleral rims were sterile in 99.3% of the grafted corneas. Deswelling media were sterile in 100% of cases. A 19- to 53-fold decrease in the percentage of rim contamination was assessed with organ culture as compared with hypothermic storage (previous studies, P < 0.0001). CONCLUSIONS: These results demonstrate the benefit of organ culture over hypothermic storage, because it allows contaminated tissue to be discarded.

Adult↗
PubMed1998

The complication of retained intraocular recipient corneal button after penetrating keratoplasty.

PURPOSE: To describe the complication of retained intraocular recipient corneal button after penetrating keratoplasty. METHOD: Case report. A 27-year-old man was referred to us because of complications after penetrating keratoplasty on the right eye. Slit-lamp examination disclosed a clear graft with a second clear corneal button behind. RESULTS: A second penetrating keratoplasty was performed successfully on the right eye. Histologic examination showed an intact epithelium and stroma vascularization of the recipient corneal button. Immunochemistry of the recipient corneal button and the first donor corneal button was performed. CONCLUSION: Although the recipient corneal button remained inside the anterior chamber for 5 months, no epithelial ingrowth occurred.

Adult↗
PubMed1998

Light microscopic evaluation of human donor corneal stroma during organ culture.

PURPOSE: To try to facilitate evaluation of corneal stroma during organ culture by means of light microscopy. METHODS: Corneal stroma of 53 consecutive organ-cultured corneas was studied by means of light microscopy during endothelial quality control. Out of 9 corneas with bad stromal evaluation, 2 were studied by means of transmission electron microscopy, and 7 were grafted. From the remaining 44 corneas with a normal light microscopic appearance, 35 were grafted. RESULTS: Stromal abnormalities consisted of bright visible structures with a cell-like shape corresponding to keratocyte injuries (i.e. cellular edema, light and dark vacuoles, cell membrane disruption and, finally, internal cytolysis) as observed by TEM. At 3 months postoperatively no clinical differences between the two groups of transplants were observed. CONCLUSION: Corneal stroma can be evaluated qualitatively and easily by means of light microscopy during organ culture. Further studies are needed to investigate whether the presence of lysed keratocytes in the graft's stroma actually influences the outcome of transplantation.

Adult↗
PubMed1998

Donor organ cultured corneal tissue selection before penetrating keratoplasty.

AIMS: Donor organ cultured corneal tissue selection before penetrating keratoplasty is carried out by taking into account different variables. The objective was to identify preoperative variables which are significantly and independently associated with transplant outcome and should effectively be taken into account before transplantation. METHODS: 231 consecutive penetrating keratoplasties were prospectively studied using organ cultured tissue. Morphometric analysis of the donor corneal endothelium was performed before transplantation. Graft survival and endothelial cell density, during the second year following transplantation, were studied both at a univariate and multivariate level. RESULTS: Recipient age, recipient rejection status, and preoperative diagnosis significantly influenced graft survival. Graft survival was higher when using corneal tissue from donors older than 80 years. Postoperative endothelial density decreased with preservation time and coefficient of variation after preservation. It increased with endothelial cell density after preservation and deswelling time, and correlated with preoperative diagnosis. CONCLUSION: Organ cultured corneas with endothelial cell density after preservation < 2000 cells/mm2, and high coefficient of variation, may be discarded before transplantation. Corneas should be preserved for less than 3 weeks, and allowed to deswell before transplantation for 2 or 3 days rather than 1 day.

Adolescent↗
PubMed1998

Cryopreservation and culture of human corneal keratocytes.

PURPOSE: To assess the effects of two different concentrations of albumin in a cryoprotective solution and two freezing methods on human corneal keratocyte ctyopreservation. METHODS: Isolated keratocytes were used for cryopreservation. Solutions of 10% dimethylsulfoxide with either 2% or 10% human albumin were used as cryoprotective agents. Cells either were transferred directly into a -80 degrees C freezer (freezing rate, 2 degrees C/min) or were cooled in a programmed freezer (1 degrees C/min until -40 degrees C and then 10 degrees C/min), which resulted in four different cryopreservation protocols. Cells were stored at -80 degrees C, then were thawed at 37 degrees C, and subsequently were cultured. Keratocytes were studied by means of trypan blue staining, growth assay, apoptosis assays, transmission electron microscopy, and immunochemistry. RESULTS: The percentage of cells that were alive after thawing ranged from 80% to 99% by trypan blue staining and from 45% to 60% by flow cytometry. The ratio of the number of living cells at the end of primary culture after cryopreservation to that before cryopreservation was significantly (P=0.04) higher after direct transfer into the -80 degrees C freezer than after controlled-rate freezing, whereas the albumin concentration had no significant influence on this ratio (P=0.45). The percentage of apoptotic cells was significantly higher after cryopreservation than in the control group of noncryopreserved cells; more than 5% 24 hours after thawing. Cryopreservation did not modify the keratocyte ultrastructure. Fibroblast growth factor dramatically decreased the serum-induced cell expression of alpha smooth muscle actin, whereas cryopreservation had no influence on this cell expression. CONCLUSIONS: A freeze-thaw trauma, which was related to cryopreservation-induced cell apoptosis, was revealed during primary culture after thawing. Direct transfer into the -80 degrees C freezer resulted in better postcryopreservation growth in the culture than controlled-rate freezing. A change in albumin concentration from 2% to 10% did not affect the results.

Actins↗
PubMed1998

[Muscular damage during isotretinoin treatment].

BACKGROUND: The effect of isotretinoin on muscle is considered to be uncommon and benign. We analyzed the files of all our patients given isotretinoin over a 5-year period and determined the incidence and gravity of its effect on muscles. MATERIALS AND METHODS: Sixty treatments with isotretinoin were studied. Myalgia and elevated CPK observed at the pretherapeutic consultation and each month or 2 months thereafter were recorded. RESULTS: Muscle symptoms were noted in 60 p. 100 of the cases: myalgia in 51 p. 100 and elevated CPK in 41 p. 100. In this group, male sex (H/F = 2.6) and sports activities (70 p. 100) were found more often. In 5 patients, CPK level was 5 times the normal, defining rhabdomyolysis. One patient interrupted treatment because of persistently high CPK levels. DISCUSSION: Myalgia and elevated CPK signal skeletal muscle involvement. These signs were more frequent in our series than in reports in the literature, probably because we systematically looked for them. Besides use of isotretinoin, one case of viral infection and sports activities, no other explanatory cause could be found. Isotretinoin could have a potentializing effect on other myotoxicity inducers (drugs, infection, fever, muscular exertion...). The benign nature of the muscle effect appears to be validated although there were some patients who had persistent and/or severe signs.

Acne Vulgaris↗
PubMed1998

[Culture of human keratocytes. Influence of culture conditions and ultrastructural aspects].

BACKGROUND: To investigate the influence of fetal calf serum (FCS) and fibroblast growth factor (FGF) on human keratocyte growth in vitro and cell differentiation, and to describe cultured human keratocyte ultra-structure. METHODS: Human keratocytes were cultured in TC 199/Ham F12 media, supplemented or not with 10% FCS, aFGF, and bFGF. Keratocyte growth was studied. Cultured keratocytes were analyzed by means of immunochemistry and transmission electron microscopy. RESULTS: Without fetal calf serum, cell population doubling occurred after 7 days of culture and no alpha smooth muscle-actin cell expression was observed. With serum, cell population increased by 1 log after 7 days of culture and all of the cells were alpha SM-actin + bFGF or aFGF-addition to the serum-containing medium resulted in a dramatic decrease in this alpha SM-actin expression. Nuclei were found to be oval and regular in cross-sections, and round and indented in frontal sections. Numerous cytoplasmic organelles were observed, as were cell expansions, gap junctions, omega-shaped structures, and fenestrations. Cultured keratocytes synthesized collagen fibers and filaments. CONCLUSION: Fetal calf serum allows human keratocytes to grow with a myofibroblast cell phenotype, whereas addition of FGF results in a fibroblast cell phenotype. Ultrastructure of cultured keratocyte is similar to that observed in situ.

Actin Cytoskeleton↗
PubMed1998

[Ultrastructural and immunohistochemical study of 3-dimensional cultures of human keratinocytes on a collagen gel].

PURPOSE: To investigate the ultrastructural and immunochemical features of three-dimensional cultures of human keratocytes in collagen gel matrix. METHODS: Human keratocytes were obtained from primary cultures of stromal explains. They were cultured in bovine type I collagen gel matrix for 6 weeks. Keratocyte-populated gels were analyzed by means of immunochemistry and transmission electron microscopy. RESULTS: Human keratocytes cultured in collagen gel matrix developed processes and formed networks of connecting cells. They showed positive staining for vimentin, collagen I, V, and VI, and connexin. Electron microscopy showed elongated cells with processes and gap junctions. Keratocytes synthesized collagen fibrils and filaments. No fibrils' organization similar to that observed in the normal human corneal stroma (i.e. parallel bundles of collagen fibrils) was observed. CONCLUSION: Ultrastructure and immunochemical phenotype of three-dimensional cultures of human keratocytes in collagen gel matrix are similar to those observed in situ. These cultures represent a useful in vitro model to study the different corneal stroma components.

Animals↗
PubMed1997

New anionic polyelectrolyte hydrogel for corneal surgery.

A new high-water-content (78%) anionic polyelectrolyte hydrogel was obtained by phase inversion (demixion) of a polymer solution containing 9.0% poly(acrylonitrile sodium methallylsulphonate), 85.0% dimethylformamide, and 6.0% saline solution (0.9% NaCl). The hydrogel is permeable to water, saline, urea, creatinine, glucose, human albumin, and saline-dissolved oxygen. Investigation of the interactions between human serum and surfaces prepared with the new yielded hydrogel, compared to serum interaction with silica-free silicone (RTV), regenerated cellulose (Cuprophan), MMA/PVP copolymer (Lidofilcon), PMMA (Perspex), FIFE (Gore-Tex), and poly(acrylonitrile sodium methallylsulphonate) hemodialysis membrane (AN-69), showed the hydrogel and hemodialysis membrane (both prepared with AN-69 copolymer) to be the only materials devoid of complement (C')-activating ability.

Biocompatible Materials↗
PubMed1997

Endophthalmitis after Lasiodiplodia theobromae corneal abscess.

BACKGROUND: Lasiodiplodia theobromae is an exceptional cause of human keratomycosis. PATIENT: We treated a 53-year-old man with fungal keratitis, which had been treated with topical betamethasone and gentamicin for 1 month, and endophthalmitis due to Lasiodiplodia theobromae. Despite intensive systemic, topical and intravitreal fungicidal treatment, enucleation had to be performed. RESULTS: The vitreous aspirate cultures were negative as of the second amphotericin intravitreal injection. However, histology revealed that the fungus was present in the cornea, ciliary body, iris and retina. CONCLUSION: The use of topical steroids may worsen the outcome of the infection.

Abscess↗
PubMed1997

Efficacy and safety of 0.3% carbomer gel compared to placebo in patients with moderate-to-severe dry eye syndrome.

PURPOSE: Carbomer gel is a water-soluble polymeric resin that has been reported to maintain the tear film in contact with the eye for an extended period. The efficacy and safety of this new artificial tear were assessed. METHODS: A multicenter, single-masked, randomized, placebo-controlled study was carried out on 123 patients with moderate-to-severe dry eyes. The placebo was a mannitol solution with benzalkonium chloride 0.008% as preservative. Patients were observed over an 8-week period, and subjective and objective changes analyzed, compared to a baseline of no therapy, after 1 to 7 days washout period from previous medication. RESULTS: All primary subjective symptoms decreased significantly in the carbomer gel-treated group compared to the placebo group (i.e., dryness, discomfort, and foreign body sensation). The carbomer gel also significantly improved the rose bengal staining score relative to placebo. When data for the primary subjective efficacy variables were stratified for disease severity, there was a statistically significant improvement from baseline by day 10 for severely affected patients and from day 42 for patients with moderate disease. Secondary subjective symptoms that improved significantly in the tear gel group compared to placebo were photophobia, erythema, tear breakup time, blurry-filmy, dry-sandy sensation, and physician impression. However, no significant improvements in the secondary subjective symptoms of tearing, itching, scaling, conjuctival discharge, palpebral conjunctival redness, bulbar conjuctival redness, conjunctival luster, relief of discomfort, ease of use, and overall acceptability were found in either group over the baseline score. In addition, neither carbomer gel nor placebo improved the baseline fluorescein staining score or the Schirmer test score. Two patients suffered local allergic reactions to the carbomer gel or its preservative, which settled on withdrawal of the medication. CONCLUSIONS: Carbomer gel was more efficacious than was placebo in improving a number of subjective and objective symptoms of moderate-to-severe dry eye syndrome. The results of this study indicate that carbomer gel was a safe as was the placebo.

Acrylic Resins↗
PubMed1997

In-vitro development of corneal epithelial cells on a new hydrogel for epikeratoplasty.

This study demonstrates the adhesion and growth of bovine corneal epithelial cells on the surface of a new hydrogel. The hydrogel, containing 78% of water and 22% of AN-69 polymer (poly(acrylonitrile-sodium methallyle sulfonate)), was obtained by phase inversion of polymer-dimethylformamide solution in physiological saline (0.9% NaCl). Experiments were also carried out using hydrogel treated with arginine, human albumin and collagen IV. Covering of hydrogel samples by epithelial cells was completed within ten days, with good cell viability. The epithelial cells spread out and formed a consistent cell layer, confirmed by immunocytochemistry experiments against cytokeratins. Transmission electron micrographs showed numerous desmosomes between cells and the presence of some membrane differentiations at the cell/hydrogel interface. This study suggests therefore that the hydrogel might be suitable for the development of artificial epikeratoplasty grafts.

Journal Article↗