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Biomedical subjects

C Baudouin

Publications and source records attributed to C Baudouin.

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

[Quaternary ammonium cytotoxicity in a human conjunctival cell line].

PURPOSE: Ophthalmic preparations can induce conjunctival toxicity, often caused by preservatives. The aim of this study was to evaluate in vitro cytotoxicity of quaternary ammonium. METHODS: Cytotoxicity tests were done on a continuous human conjunctival cell line using microplate cold light cytofluorimetry. Membrane integrity (neutral red test), DNA condensation (Hoechst 33342 test) and reactive oxygen species (ROS) production (dichlorofluorescein diacetate and hydroethidine tests) were evaluated on living cells treated with different concentrations of benzalkonium chloride, benzododecinium bromide and cetrimide (0.00001 to 0.01%) after 15 minutes of treatment or 15 minutes and 24 hours of cell recovery. RESULTS: All the compounds tested showed similar in vitro effects. Using the neutral red test, we observed a decrease in membrane integrity even at 0.005% and 0.01% (p < 0.001) and after a short time (15 minutes). A stimulation of ROS production (H2O2 and O2) was observed at 0.00001% and above (p < 0.001), associated with a chromatine condensation due to an apoptotic phenomenon. CONCLUSION: A necrotic phenomenon is suggested at high concentrations of quaternary ammonium preservatives whereas an apoptotic mechanism exists for lower concentrations. This toxicity observed in vitro can explain some of the ocular surface damage caused by long-term use of preserved eye-drops.

Anti-Infective Agents, Local↗
PubMed1998

Expression of Fas-Fas ligand antigens and apoptotic marker APO2.7 by the human conjunctival epithelium. Positive correlation with class II HLA DR expression in inflammatory ocular surface disorders.

Fas antigen (CD95) is a membrane receptor that plays a major role in induction of apoptosis. In surface conjunctival epithelial cells the expressions of Fas, Fas ligand, the apoptotic marker APO2.7 and of HLA DR class II antigen, a membrane marker known to be expressed in inflammatory conditions were investigated. Impression cytology specimens were collected in 65 patients: 20 normal ones, 15 contact lens wearers, 20 receiving chronic topical antiglaucoma treatment and 10 with nonspecific chronic conjunctivitis. Cells were processed for flow cytometry, using monoclonal antibodies to Fas, Fas ligand, APO2.7, HLA DR antigens and a negative isotypic control. Percentages of positive cells were recorded and levels of fluorescence quantified using fluorescent beads at standardized fluorescence intensities. In addition, a human conjunctival cell line was incubated with anti-Fas stimulating antibodies in order to test Fas-induced apoptosis in vitro. Fas was found in all specimens in most of the conjunctival cells, but quantitation of levels of fluorescence showed a significantly higher expression in pathologic eyes than in normal ones. Fas ligand and APO2.7 were variably expressed by conjunctival cells, but in a significantly higher percentage of cells in pathological eyes than in normal ones. In these eyes a strong expression of HLA DR was also observed, whereas normal eyes showed lowest levels. Highly significant correlations were found between Fas, Fas ligand, APO2.7 and HLA DR levels. Anti-Fas antibodies in vitro induced strong apoptosis in epithelial cells as confirmed by APO2.7 expression and DAPI staining. This study confirms that conjunctival epithelial cells normally express Fas antigen, and more inconstantly its ligand, as do corneal ones or keratinocytes. Fluorescence quantitation by flow cytometry showed much higher expression in inflammatory eyes than in normal ones, and demonstrated a strong correlation between apoptotic and inflammatory pathways in the ocular surface.

Adult↗
PubMed1998

Histopathological effects of topical ophthalmic preservatives on rat corneoconjunctival surface.

PURPOSE: Long term use of topical drugs has clearly been shown to induce toxic immunopathological changes in the ocular surface. However, little is known concerning the respective roles of active compounds and preservatives. Benzalkonium chloride (BAC) is the most used preservative and its cytotoxicity is well known, but other preservatives have not yet been clearly evaluated. We thus performed a comparative study to investigate toxic side effects induced in the rat ocular surface by applications of various preservatives, with special attention to inflammatory infiltrates. METHODS: A total of 35 brown Norway rats were divided into seven groups of five each. They received, for one month, in both eyes, either 0.01% cetrimonium chloride, 0.01% benzalkonium chloride, 0.01% benzododecinium bromide, 0.004% thiomersal, 0.05% methyl parahydroxybenzoate or phosphate-buffered saline (PBS), the last group remaining untreated. Then, animals were sacrificed and eyes were processed for histological and immunological procedures with monoclonal antibodies to rat immunocompetent cells. RESULTS: When compared to controls, all preservative-treated eyes consistently showed corneal and conjunctival damage, including epithelial alterations, various degrees of keratinization and inflammatory infiltrates at the limbus and within the conjunctival stroma and epithelium. No difference was found between the five tested drugs. CONCLUSIONS: This study confirms that most preservatives used in ophthalmic eyedrops may similarly induce strong histopathological and inflammatory changes in the ocular surface after short term use. Although obtained in animal model, these results confirm strong toxic side effects in patients with preexisting ocular surface disorders and/or receiving topical drugs for long periods.

Animals↗
PubMed1998

Short-term comparative study of topical 2% carteolol with and without benzalkonium chloride in healthy volunteers.

AIM: A crossover, randomised double blind study was undertaken in 30 healthy volunteers, in order to compare the tolerance of 2% carteolol with and without preservative in short term use. METHODS: Complete ophthalmic examinations were performed before and 30, 60, and 180 minutes after instillation of one drop of the solution, and after 3 days of preservative treatment. After a 5 day washout, the same examinations were done with the second drug. RESULTS: Results showed good general tolerance for both formulations. No significant difference in subjective tolerance, corneal aesthesiometry, punctuate keratitis, Schirmer's test, intraocular pressure (IOP) decrease (about 25% in the two groups at 3 hours, 10% after 3 days of treatment), resting cardiac frequency, or blood pressure was observed. However, break up time was significantly reduced from baseline by preserved carteolol both at 3 hours (10.40 (5.9) seconds to 6.15 (3.9) seconds, p = 0.001) and after 3 days (7.72 (5.5) seconds, p = 0.04). Preservative free carteolol did not significantly change the break up time (baseline 9.08 (5.7) seconds; 3 hours = 7.88 (5.5) seconds, not significant; day 3 = 8.35 (5.8), non-significant). CONCLUSIONS: These results confirm that carteolol is well tolerated, either with or without preservative. The preservative free group showed better stability of the tear film, without loss of effect on IOP. This difference, although mild in the healthy young subjects in the present study could be much more relevant in those patients treated long term, older patients, and/or those suffering from ocular surface disorders. In such instances, preservative free drugs could be of potential benefit to protect the lacrimal fluid integrity and corneoconjunctival surface.

Administration, Topical↗
PubMed1998

CA 19-9 ELISA test: a new method for studying mucus changes in tears.

AIMS: This study investigated mucus changes in the tears in various eye conditions using impression cytology. The quantity of mucins was measured by enzyme linked immunosorbent assay (ELISA) using the tumour marker CA 19-9. This assay quantifies the sialylated Lewis(a) structure mainly associated with ocular mucins. METHODS: Impression cytology was performed using a cellulose nitrate membrane, on 53 healthy patients, 50 glaucoma patients treated with beta blockers, 24 patients suffering from dry eye syndrome, and 45 contact lens wearers. The tear film glycoproteins were eluted and CA 19-9 was measured. RESULTS: CA 19-9 content expressed as kilo units (kU) per microgram of tears was significantly decreased in dry eye syndrome (25.8 kU (SD 17.3)/microgram) (p < 0.05), glaucoma patients over 60 years (28.9 (19.5) kU/microgram) (p < 0.05), and contact lens wearers (28.4 kU (18)/microgram) (p < 0.05), when compared with healthy individuals (39.4 kU (22.2)/microgram). CONCLUSION: Impression cytology can be regarded as a valuable method for obtaining samples of glycoconjugates of mucin. The decrease of sialylated chains observed with this method confirms the hypothesis that some quantitative changes in the tear film may be encountered in ocular surface disorders.

Adult↗
PubMed1998

Inflammation measurement and immunocharacterization of cell proliferation in an experimental model of proliferative vitreoretinopathy.

An experimental model of proliferative vitreoretinopathy was developed in the rabbit eye by injecting a solution of human platelet-rich plasma. In this model we evaluated the progression with time of intraocular inflammation and the rate and origin of cell proliferation. A sterile solution adjusted to 107 platelets was injected into the right eye of a total of 46 pigmented and 14 albino rabbits. Animals were sequentially sacrificed at days 7, 14, 21 and 1 month after injection. Clinical evaluation of vitreoretinal proliferation, using a classification in six grades, and of anterior segment inflammation assessed by a Laser Flare Meter, were done for 1 month after injection, before histopathological analysis. Eighty percent of eyes developed tractional retinal detachment in 1 month. Histopathology showed intense cell migration and proliferation in the area of the ciliary body, as early as the seventh day, then further increasing rapidly. Infiltrates were composed of cytokeratin- and vimentin-expressing cells. Abnormal expression of vimentin was also found in ciliary and retinal epithelia and in M¿ller cells. Inflammation measured by the Laser Flare Meter was maximal at day 11 and then reached a plateau at significantly higher levels than controls. Albino rabbits showed significantly lower grades of proliferation, as compared to pigmented rabbits. This study thus clarified some characteristics of experimental vitreoretinal proliferations that that proved similar to those in human diseases, such as the involvement of ciliary body and retinal pigment epithelium, the existence of inflammatory reactions preceding cell proliferation and strong changes in intermediate filaments. This may provide a simple and valuable model for antiproliferative assays and shed some light on the pathogenesis of intraocular proliferative disorders.

Albinism↗
PubMed1998

[Value of lacrymal IgE determination and conjunctival cytology in the diagnosis of chronic conjunctivitis].

PURPOSE: Chronic conjunctival inflammatory diseases may depend upon various strongly intricated mechanisms. Discriminating allergy from nonspecific inflammation has become of striking importance for diagnosis and treatment. We investigated conjunctival inflammatory response by comparing two objective biological tools, tear IgE detection and HLA DR expression by conjunctival epithelium, as indirect indicators of activation of the Th1 and Th2 subsets, respectively. METHODS: Sixty-eight patients (135 eyes) with chronic conjunctivitis underwent tear IgE dosage by an ELISA technique and quantification of HLA DR expression in impression cytology specimens. 34 had direct or indirect clinical indications of allergic mechanisms, 22 had chronic conjunctivitis without any sign of allergy, and 12 suffered from isolated nonallergic dry eyes. RESULTS: Patients clinically considered as allergic only showed positive IgE in 31 out pf 68 eyes (46 per cent), whereas 11/44 (25%) and 7/24 (29%) eyes with nonspecific conjunctivitis and dry eyes respectively were also positive. HLA DR positivity in epithelial cells was found in 18/61 (29.5%), 15/40 (37.5%) and 9/22 (41%) eyes, respectively. HLA DR expression by epithelial cells was negatively correlated with tear IgE, as most specimens positive to one criterion were negative to the other one (37 eyes DR+ IgE-, 35 eyes DR- IgE+, and 5 eyes DR+ IgE+; chi-square: p = 0.0001). CONCLUSION: As IgE synthesis and HLA DR induction may represent indirect indicators of the activation of the Th1 and Th2 subsets, association of these two simple tests could be interesting for the routine assessment of the mechanisms of inflammatory ocular surface diseases.

Adult↗
PubMed1998

[Evaluation by laser flare meter of the inflammatory response after cataract surgery].

PURPOSE: To prospectively evaluate use of the laser flare meter the inflammatory response after phacoemulsification with four different types of intraocular lenses. METHODS: Measurements with the Kowa laser flare meter FC-500 were done before surgery and at 1, 6 and 21 days following standard phacoemulsification with corneal incision in 157 patients. The patients were randomized in four groups to receive HSM IOL (group I), foldable acrylic IOL (group II), foldable three-piece silicone (group III), and foldable single-piece silicone (group IV). RESULTS: Overall, mean flare values were increased at D1, and decreased rapidly to normal values at D21. Intragroup analysis showed a slight increase of flare value observed in the PMMA group (p = 0.0015) and silicone monobloc group (p = 0.001) at D21 compared to D0. There was no statistical difference found between D0 and D21 in the acrylic and the silicone three pieces groups. At D1, a significant increase of flare values was observed in the PMMA (28.9 ph/ms) and silicone three pieces (28.8 ph/ms) groups, as compared to silicone monobloc group (22 ph/ms). At D21, the acrylic group had a significantly lower mean value than PMMA and silicone monobloc groups. No statistical difference was observed between acrylic and three-piece silicone at D21. CONCLUSION: This study shows that the inflammation in the four groups was very low after phacoemulsification by a corneal incision and attempts to explain the impact of the incision length on the breakdown of blood-aqueous barrier.

Acrylic Resins↗
PubMed1998

[Abnormalities of the ocular surface in patients with AIDS].

PURPOSE: AIDS patients more and more complain from conjunctival symptoms related to dry eyes and conjunctivitis, but little is known about ocular surface abnormalities in these patients. We used impression cytology (IC) and tear IgE to assess inflammatory status of the ocular surface in AIDS. METHODS: IC were taken in 30 patients infected by HIV (including 28 AIDS patients). After collecting general clinical information, and CD4 rate, we made a complete ophthalmological examination (Schirmer test, BUT, Lissamine green and tear IgE). IC were processed by an immunofluorescence technique with antibodies to HLA DR: an inflammatory marker normally restricted to conjunctival dendritic cells; and to APO 2.7 an apoptotic cell marker. RESULTS: Seventy per cent suffered from subjective and/or objective signs, and BUT was abnormal in 70% of patients. Tear IgE was increased in 36% of the eyes, even without known allergy. A decrease in density of dendritic cells and an abnormal expression of HLA DR antigens by epithelial cells were common features in both groups (respectively 90% and 80% of the eyes). An increase of the APO 2.7 marker was significantly found in 70% of eyes. We found no correlation between clinical abnormalities and laboratory findings. However there was a correlation between the blood CD4 decrease and the HLA DR antigen overexpression. Tear IgE were related to HLA DR expression. CONCLUSION: This work shows that even when AIDS patients are asymptomatic they may present significant alterations of the ocular surface probably due to their immunological disorders.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Immunophenotyping of human dendriform cells from the conjunctival epithelium.

PURPOSE: Conjunctival Langerhans cells are bone marrow-derived, antigen-presenting cells that play a major role in the immune response of the ocular surface, but they have as yet been little investigated, either functionally or phenotypically. This study was undertaken in impression cytology to provide an extended immunophenotype of human conjunctival dendriform cells. METHODS: Immunostaining procedures were used to seek for the expression of the following 30 membrane antigens related to the immune system, using dendriform cells obtained in conjunctival specimens from 80 normal subjects and 105 with chronic conjunctivitis: class II antigens HLADR and DQ, CD1a (T6) and CD5, which usually mark Langerhans cells, macrophage markers CD14, CD36 and CD63, various lymphocyte antigens (CD2, CD4 and CD8), receptor to interleukin 2 (CD25), adhesion molecules and integrins (CD11a, CD11b, CD11c, CD18, CD29, CD41, CD61), the selectin CD62, ICAM-1 (CD54), ICAM-3 (CD50) and ELAM-1, CD45RO, related to activation of immune cells, and its ligand CD22, receptors to immunoglobulins (CD23 and CD32) and complement (CD21), transferrin receptor CD71, tryptase and vimentin, were thus investigated. RESULTS: Conjunctival dendriform cells reliably expressed several antigens: class II antigens HLA DR and HLA DQ, CD1a, vimentin, CD11a and CD18 (LFA-1), CD14, CD22, CD36, CD45RO, ICAM-3 and CD63. Other markers were only occasionally found (CD4, CD11b, CD29, CD32 and CD54), and the remaining above antigens were not expressed. No relevant difference was found between normal and inflammatory specimens in the immunophenotype of dendriform cells. CONCLUSIONS: This study sheds light on the main antigen-presenting cells of the ocular surface. The conjunctival cells share common immunophenotypic features with those from skin or mucosae, but our results showed some discrepancies, probably related to the specific immune status of the ocular structures.

Adult↗
PubMed1997

Flow cytometry in impression cytology specimens. A new method for evaluation of conjunctival inflammation.

PURPOSE: To investigate feasibility and potential uses of flow cytometry in impression cytology as a new procedure to assess and quantify conjunctival inflammation. METHODS: Specimens for cytology were collected by impression from 30 patients with various chronic ocular surface disorders and from 10 normal subjects. Two specimens were obtained in each eye: One was transferred onto a glass slide and processed by immunofluorescence with antibodies to human leukocyte antigen (HLA)-DR antigens; cells from the other were suspended in phosphate-buffered saline for flow cytometry. Monoclonal antibodies to HLA-DR antigens and CD23, the low affinity receptor to immunoglobulin E, were used. RESULTS: Abnormal expression of HLA-DR and CD23 by conjunctival cells was found in 13 of 18 dry eyes and in 20 of 22 eyes with chronic conjunctivitis, whereas specimens remained almost negative (less than 10% of cells were positive) in normal eyes. Percentages of positive cells ranged between 20% and 98% of all conjunctival cells. Correlation between the two methods, immunocytology and flow cytometry, was highly significant (coefficient of correlation 0.77, P = 0.0001). Moreover, HLA-DR positivity, at its strongest intensity, was observed in a minority of cells (1% to 12%), most of which were resident class II-expressing dendritic cells. Percentages of those cells expressing high levels of HLA-DR were 3 +/- 1.2% in normal eyes, 5.8 +/- 4% in dry eyes (P = 0.05), and 5.9 +/- 3.5% in eyes with chronic conjunctivitis (P = 0.02). CONCLUSIONS: Results of this preliminary study confirm that conjunctival epithelial cells may abnormally express inflammatory markers in chronic ocular surface disorders. Development of flow cytometry in analysis of cytologic specimens provides a new, sensitive, and objective tool for exploring conjunctival pathology.

Antibodies, Monoclonal↗
PubMed1996

Detection of JC virus DNA in the peripheral blood leukocytes of HIV-infected patients.

OBJECTIVES: To assess whether JC virus (JCV) DNA is frequently harboured by peripheral blood leukocytes (PBL) in HIV-positive patients, before the onset of progressive multifocal leukoencephalopathy (PML). DESIGN: The polyomavirus JCV induces PML in immunocompromised persons and particularly AIDS patients. Leukocytes may play a central part in the onset of PML, but their precise role in JCV latency and reactivation still remains hypothetical. The controversial presence of JCV DNA in PBL has been, until now, investigated only among small groups of patients. We therefore studied 157 HIV-positive persons and compared them with 65 HIV-negative immunocompromised patients. METHODS: DNA was extracted from PBL. The presence of JCV DNA was demonstrated by the polymerase chain reaction (PCR) alone or combined with a molecular hybridization assay. RESULTS. The presence of JCV DNA was ascertained by PCR and hybridization in 28.9% of 135 HIV-infected persons at all stages of HIV infection and only 16.4% of 61 HIV-negative immunocompromised patients. No correlation could be drawn between the detection of JCV DNA and the clinical or biological status of the HIV-positive patients. CONCLUSIONS: JCV DNA is detectable in the PBL of 28.9% of HIV-infected persons, even in the early stages of infection. JCV is more seldomly amplified in HIV-negative immunocompromised patients. Further work is in progress to determine the prognostic value of the presence of JCV DNA in the blood of HIV-positive patients.

Adult↗