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Biomedical subjects

C Baudouin

Publications and source records attributed to C Baudouin.

At least 145 records · Page 8Linked to original sources
PubMed1992

Immunopathological findings in conjunctival cells using immunofluorescence staining of impression cytology specimens.

The conventional technique of impression cytology provides a non-invasive method for the evaluation of conjunctival epithelium alterations. Using indirect immunofluorescence procedures two inflammatory markers, class II MHC antigens HLA DR and the receptor to IgE (CD23), were sought in impression cytology specimens obtained from 80 patients. In normal subjects conjunctival epithelial cells did not show any reactivity. Only scattered dendritic cells were found to express class II antigens but not the receptor to IgE. In contrast patients with chronic conjunctivitis of various aetiologies, mainly infectious or allergic, had 40-100% of brightly positive conjunctival cells for one or both antigens. In these cases epithelial cells and goblet cells reacted similarly. Twenty four eyes in 12 patients with idiopathic dry eye syndrome disclosed results similar to those from normal conjunctival specimens. However 18 other specimens from patients suffering from idiopathic tear deficiency but undergoing multiple substitutive treatments for dry eye had moderate to strong positivity for HLA DR and/or the receptor to IgE (20-100% of cells). As these results were independent of the degree of squamous metaplasia the expression of these membrane markers may reflect local inflammation in addition to tear deficiency, possibly due to sensitisation to the eye drops used. These immunocytological techniques thus provide useful methods of investigating conjunctival inflammation and allergy. They may constitute valuable aid in the diagnosis and appropriate treatment of ocular surface disorders.

Adult↗
PubMed1992

Immunohistological study of subretinal membranes in age-related macular degeneration.

An immunohistological study was performed on 6 specimens of subretinal membranes obtained surgically from patients suffering from age-related disciform macular degeneration. using immunoperoxidase procedures, we found in those membranes large amounts of IgG, IgA and IgE as well as C1q, C3c and C3d complement components diffusely distributed in the connective stroma and within the new blood vessel walls. Moreover, subretinal membranes contained numerous isolated HLA-DR- and -DQ-expressing cells, including glial, pigment epithelial and vascular endothelial cells. Monoclonal antibodies to immunocompetent cells disclosed only rare B and natural killer lymphocytes or suppressor-cytotoxic T cells, as well as some monocytes. These results show that immune phenomena are involved in proliferative changes associated with subretinal neovascularization. In addition, they suggest there are interactions between the immune system and peptide growth factors.

Antibodies, Monoclonal↗
PubMed1992

Transferrin receptor expression by retinal pigment epithelial cells in proliferative vitreoretinopathy.

Immunotoxins directed against a membrane marker of cell proliferation, transferrin receptor, were investigated to inhibit the growth of retinal pigment epithelial (RPE) cells in proliferative vitreoretinopathy (PVR). We undertook an immunocytological study in specimens of vitreous, subretinal fluid, and epiretinal membranes from patients with PVR to address the expression of transferrin receptor by proliferating pigment epithelial cells during the course of PVR and in normal human ocular structures. Thirty four specimens of vitreous and subretinal fluid, as well as seven epiretinal membranes, were immunocytologically examined using monoclonal antibodies to transferrin receptor. They showed a strong expression of this marker by a large majority of the cells in these two periretinal fluids (mean percentages 80 and 91% in vitreous and subretinal fluid, respectively). In contrast, only a few cells within epiretinal membranes were found to express transferrin receptor. In normal human eye sections conjunctival and corneal epithelial cells, subcapsular epithelium of the lens strongly expressed transferrin receptor, whereas RPE cells remained negative to antitransferrin receptor antibodies. A few iris or ciliary pigment epithelial cells reacted weakly. Thus, this study shows that most intravitreal and subretinal fluid proliferating cells strongly express transferrin receptor on their surface. Also confirmed is that immunotoxins to this membrane antigen could constitute potentially useful therapeutic agents in PVR.

Adult↗
PubMed1991

Acidic FGF and other growth factors in preretinal membranes from patients with diabetic retinopathy and proliferative vitreoretinopathy.

The development and extension of fibrovascular or fibroglial membranes onto the retinal surface are a major cause of visual loss in diabetic patients with proliferative retinopathy and in patients suffering from retinal detachment with proliferative vitreoretinopathy. The pathogenesis of these proliferative diseases, however, remain poorly understood and the nature of growth-promoting mediators implicated in these phenomena has not been determined yet. Using indirect immunofluorescence procedures, three different growth factors known to be mitogenic for various cell components of preretinal membranes, acidic fibroblast growth factor, epidermal growth factor and insulin-like growth factor type I, were sought in 14 specimens of preretinal proliferative tissues. Similar results were obtained in diabetic preretinal membranes and tissues from patients with proliferative vitreoretinopathy. The three different growth factors were found diffusely in the connective stroma and around new blood vessels within the vascular walls. Some fibroblast-like and pigment epithelial-derived cells more markedly reacted with anti-growth factor antibodies. These results provide indications on the eventual involvement of three potent growth factors in intraocular proliferative diseases, but whether or not these mediators play an active role in the development of preretinal membranes remains to be determined.

Adult↗
PubMed1991

Immunocytology of cellular components in vitreous and subretinal fluid from patients with proliferative vitreoretinopathy.

Proliferative vitreoretinopathy accounts for most of failures in retinal detachment surgery. It results from the formation of membranes spreading onto inner and outer surfaces of the detached retina and within the vitreous body, but the nature of the growing cells and the mechanisms of proliferation remain speculative. A cytological study was thus undertaken on 35 specimens of vitreous and subretinal fluid obtained surgically in patients with proliferative vitreoretinopathy. Various types of cells were identified: typical pigment epithelial cells, lightly pigmented and large totally unpigmented macrophage-resembling cells, smaller unpigmented cells and lymphocytes. Immunocytological procedures with 10 different monoclonal antibodies directed against different markers of epithelial and immunocompetent cells showed the epithelial nonmacrophagic origin of the intravitreal and subretinal cells, as most of these cells were positive for cytokeratin but remained negative for macrophage markers. Examination of intravitreal pigment granules, using autofluorescence analysis by epi-illumination and toluidine blue staining, showed two distinct populations of pigmented cells, one containing melanin and the other lipofuscin, suggesting that pigmented cells could originate from the retinal and ciliary pigment epithelia. As concerns lymphocyte identification, only B cells were seen, whereas no T lymphocyte could be found. Fibronectin was found on a minority of cells in 4 vitreous specimens, but cells positive for glial fibrillary acidic protein could not be seen. These results confirm the involvement of pigment epithelial cells and the strong morphological changes they undergo during the course of proliferative vitoretinopathy, but the mechanisms of proliferative phenomena after retinal detachment remain to be determined.

Adolescent↗
PubMed1991

[Immunomorphological study of the vitreous body and subretinal fluid in vitreoretinal proliferation].

Proliferative vitreoretinopathy (PVR) is a major complication of rhegmatogenous retinal detachment. Its pathogenesis remains poorly understood and the accurate nature of the growing cells on both surfaces of the detached retina has not been yet determined. We undertook an immunocytological study on 28 specimens of vitreous or subretinal fluid removed from patients with PVR. Five main types of cells could be identified: heavily pigmented cells, poorly pigmented ones, large totally unpigmented macrophage-like ones, smaller unpigmented cells and lymphocytes. Analysis of intravitreal pigment granules showed two different types of pigmented cells, those with lipofuscin and melanin and those with melanin without any granules of lipofuscin, which could originate from ciliary or iris pigment epithelia. Immunostaining procedures confirmed the epithelial non macrophagic lineage of the intravitreal and subretinal cells. Lymphocytes were only B cells. These results confirm the importance of proliferative process during the course of PVR and shows the involvement of other ocular structures other than the retinal pigment epithelium.

Aqueous Humor↗
PubMed1991

Class II histocompatibility antigen expression by cellular components of vitreous and subretinal fluid in proliferative vitreoretinopathy.

Proliferative vitreoretinopathy (PVR) is the major cause of failure in retinal detachment surgery. It is characterized by the formation of membranes extending along both surfaces of the detached retina and within the vitreous, but the nature of the growing cells has not yet been determined. Using cytologic and immunocytologic procedures with 13 different monoclonal antibodies directed against Class II histocompatibility antigens and various markers of epithelial and immunocompetent cells, 30 specimens were studied of vitreous or subretinal fluid removed from patients with PVR. Five main types of cells could be identified: heavily pigmented cells, poorly pigmented ones, large totally unpigmented macrophage-resembling ones, smaller unpigmented cells, and lymphocytes. Analysis of intravitreal pigment granules, using autofluorescence by epiillumination and cytologic procedures, showed two different populations of pigmented cells: one with autofluorescent lipofuscin granules and the other with exclusively melanin pigment. Immunostaining procedures confirmed the epithelial nonmacrophage lineage of the intravitreal and subretinal cells because most of these cells were positive for cytokeratin but negative for macrophage markers. In addition, 40-100% of these epithelial-derived cells strongly expressed Class II histocompatibility antigens HLA-DR and -DQ. Lymphocytes were found in 13 specimens; B-cells were seen, but no T-lymphocytes could be identified. These results confirm the involvement of retinal pigment epithelial cells and the strong morphologic changes they undergo during the course of PVR. Moreover, the expression of Class II histocompatibility antigens by the growing cells may be related to inflammatory phenomena, but their eventual role in the development and the extension of periretinal proliferation has not been determined.

Adolescent↗
PubMed1990

Immunohistologic study of epiretinal membranes in proliferative vitreoretinopathy.

We performed an immunohistologic study on 11 specimens of epiretinal membranes surgically obtained from patients who had rhegmatogenous retinal detachment with proliferative vitreoretinopathy. Immunostaining procedures were used to identify immunoglobulin and complement deposits, to visualize class II antigen expression by proliferating cells, and to determine eventual infiltration by cells of the immune system. Diffuse deposits of IgG, IgA, IgE, C1q, C3c, and C3d were found in epiretinal membranes, whereas numerous cells, including glial or pigmented epithelial cells, expressed HLA-DR and HLA-DQ antigens. Some macrophages and B or T8 lymphocytes were identified. These results suggest activation of the immune system during the course of proliferative vitreoretinopathy. Class II antigen expression could be dependent upon growth-promoting factors and interferon gamma and could play a crucial role in this immune reaction, which resulted in immunoglobulin deposition and activation of complement. However, the eventual role of immune phenomena in the extension of proliferative processes remains to be determined.

Adult↗
PubMed1990

[Acanthamoeba keratitis in subjects with contact lenses].

A new case of Acanthamoeba keratitis in a young woman using contact lenses is reported. Although the patient strictly complied with decontamination rules, she developed a huge corneal abscess invading the anterior chamber. After a misleading initial phase, the diagnosis was suspected on clinical grounds and was confirmed by parasitologists. The infection followed a favourable course, thereby avoiding surgery and its unpredictable consequences, but an opaque speck remained in the centre of the cornea. This case illustrates a pathology which is getting less and less exceptional, even in France where such pathogens can be found in the water for normal household use. Subjects wearing contact lenses and who are particularly exposed should be warned of the risk of infection they incur. Doctors should be taught to bear this diagnosis in mind in order to guide parasitological investigations and to obtain confirmation as early as possible.

Acanthamoeba↗
PubMed1990

Class II antigen expression in diabetic preretinal membranes.

Using immunofluorescence and immunoperoxidase procedures, we found large amounts of IgG, IgA, IgM, and IgE, as well as C1q, C3c, and C3d, in the connective stroma and within the vascular walls on eight specimens of preretinal membranes obtained from diabetic patients with proliferative retinopathy. The membranes contained many isolated human leukocyte antigen (HLA) DR- and DQ-expressing cells, and vascular endothelial cells strongly expressed class II determinants. Monoclonal antibodies to immunocompetent cells disclosed only rare B lymphocytes or suppressor/cytotoxic T cells and few monocytes. These findings confirm previous evidence of immune reactions in the pars plana of patients with proliferative diabetic retinopathy, and suggest that an autoimmune reaction is a factor in this complication. It is yet not possible to determine whether this reaction is a nonspecific consequence of the vasoproliferative processes or if it plays a direct role in the development and extension of preretinal membranes.

Adult↗
PubMed1990

HLA DR and DQ expression on human retinal pigment epithelial cells in vitro.

In a previous immunohistopathological study, we demonstrated a deviant expression of class II antigens on the uveal pigment epithelial cells of patients with proliferative diabetic retinopathy. The mechanisms triggering this abnormal expression by epithelial cells are not well known, and we tried to induce this phenomenon on primary cultures of human retinal pigment epithelial (RPE) cells. Confluent RPE-cell monolayers were supplemented with several biological or chemical reagents [recombinant interferon gamma, phytohemagglutinin A-P (PHA-P), phorbol-myristate acetate (PMA), recombinant interleukin-2, fibroblast growth factor (FGF), Insulin], to investigate their ability to induce HLA DR and DQ expression. On days 1, 3 and 5 after stimulation, the cells were incubated with monoclonal antibodies directed against human class II antigens: all reagents used failed to induce class II antigen: all reagents used failed to induce class II antigen expression. However, on day 7, we demonstrated the presence of numerous positive HLA DR and HLA DQ cells stimulated by gamma interferon, the percentages being closely related to the dose of this lymphokine. These findings, together with those of other investigators and our previous work on uveal pigmented epithelial cells in diabetic patients, may shed light on the exact implication of RPE in many poorly documented ocular diseases.

Aged↗
PubMed1990

Suitability of and tolerance to Iotrolan 300 in bronchography via the fibreoptic bronchoscope.

The contrast agent Iotrolan 300 has potential advantages for bronchography over previous agents in that it can be injected directly through the bronchoscope and it does not obscure bronchoscopic vision or interfere with further bronchoscopic procedures. It was used for selective bronchography in 20 patients with suspected bronchiectasis. Side effects and change in FEV1 and in arterial oxygen saturation were compared in these patients and in 14 patients undergoing bronchoscopy for suspected carcinoma. Thirteen of the 20 patients undergoing bronchography had side effects, mainly headache, nausea, and a feeling of heat or flushing. The fall in FEV1 at four hours (0.3 l) did not differ from the fall in the control group (0.1 l). The fall in arterial oxygen saturation (SaO2) during bronchography (9.4%) did not differ significantly from the fall during bronchoscopy in the control group (6.1%). Iotrolan gave good quality bronchograms, which in all cases provided a diagnosis. Iotrolan appears to be suitable for bronchography by fibreoptic bronchoscope and to be well tolerated.

Bronchiectasis↗
PubMed1990

Acidic fibroblast growth factor distribution in normal human eye and possible implications in ocular pathogenesis.

Using a rabbit anti-acidic fibroblast growth factor (anti-aFGF) antiserum, we tried to establish a precise mapping of aFGF localization in normal human ocular structures, from samples obtained by autopsies. Cell cultures of retinal pigment epithelium and ciliary pigment epithelium were also established and immunofluorescence studies were performed after 1 month. Corneal and conjunctival epithelia were strongly positive for anti-aFGF antibodies as well as the subcapsular epithelium of the lens. The cortical fibers were weakly reactive and the lens nucleus negative. A strong intracytoplasmic reactivity was observed in the pigmented and nonpigmented epithelial cells of ciliary processes and pars plana, both ex vivo and in vitro. Retina was brightly positive, mostly in the photoreceptor and plexiform layers. The possible involvement of aFGF in normal eye growth and in various ocular diseases was then discussed.

Adult↗
PubMed1989

Immunohistologic study of proliferative vitreoretinopathy.

An immunohistologic study was performed on pars plana specimens obtained by biopsy in ten patients with rhegmatogenous retinal detachment, with or without proliferative vitreoretinopathy. Using immunofluorescence or immunoperoxidase procedures, linear deposits of IgG, IgA, and complement components were found in the eight cases of retinal detachment with proliferative vitreoretinopathy at the basal pole of the pigment epithelial cells and within the stroma. In contrast, these deposits were absent from the normal pars plana and from the retinal detachment without proliferative vitreoretinopathy. Moreover, pigment and nonpigment epithelial cells were found to express HLA-DR and HLA-DQ determinants in six of the eight patients with proliferative vitreoretinopathy. Our results are similar to those obtained in a previous study on proliferative diabetic retinopathy, which suggests the involvement of autoimmune phenomena in proliferative diseases and eventual interactions between the immune system and peptide growth factors. However, whether or not this immune reaction functions in the initiation or extension of intraocular proliferative syndromes remains to be determined.

Complement System Proteins↗
PubMed1989

Detection of HBs antigen, DNA polymerase activity, and hepatitis B virus DNA in tears: relevance to hepatitis B transmission by tears.

Hepatitis B surface antigen, DNA polymerase, and hepatitis B virus DNA have been sought in the tears of 72 patients. These markers were detected in a high percentage of hepatitis B carriers, which proves the presence of hepatitis B virus in the tears and raises the question of its eventual transmission in this way. The severity and extreme contagiousness of hepatitis B together with the increasing number of virus carriers justify systematic sanitary rules among ophthalmic clinicians and staff, but vaccination remains the best mean of limiting the spread of the disease.

DNA, Viral↗