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M Filipec

Publications and source records attributed to M Filipec.

At least 37 records · Page 2Linked to original sources
PubMed1999

Cell subpopulations in failed human corneal grafts.

BACKGROUND/AIMS: Inflammatory cells and antigen presenting cells (APC) are not present under normal circumstances in the centre of the healthy cornea. The purpose of this study was to investigate and phenotype the inflammatory cell populations, particularly with reference to T cell subpopulations and macrophages, and to localise dendritic cells (DC) and other MHC class II positive cells in three groups of grafted corneas: rejected non-inflamed, rejected inflamed grafts, and control dystrophic explants. METHODS: 15 corneal buttons removed during keratoplasty from non-inflamed "quiet" previously grafted corneas, five inflamed corneas requiring urgent regrafting for "graft melting" (in "high risk" corneas), and 10 control dystrophic opaque corneas explanted during their first graft procedure were examined. Cryosections of corneas were immunostained with a panel of monoclonal antibodies (mAb) against CD3, CD4, CD8, CD14, CD25, CD68, HLA-DP, and HLA-DR molecules using the StreptABC method. DC were detected by dual immunostaining as CD1a+ and MHC class II+ and CD19-. Cell densities in immunostained tissue sections were evaluated using a scale from 0 to +4. RESULTS: Immunostaining in control dystrophic corneas was negative for all antibodies. A moderate to high density of CD8+, CD14+, and CD68+ cells was observed in the majority of rejected non-inflamed as well as in rejected inflamed corneal buttons. Strong positivity for HLA-DP and HLA-DR molecules in the epithelium, stroma, and endothelium was also demonstrated. Weak positivity for CD4 and CD25 was observed in six of 15 and 11 of 15 rejected corneas, respectively. The presence of dendritic cells in the basal layer of the epithelium and in the stroma was observed in 50% of the grafts. CONCLUSIONS: A high frequency of macrophages, the presence of DC in the explants, and strong expression of HLA-DP and HLA-DR molecules on resident cells are characteristics of rejected corneal allografts, whether actively inflamed or not. The presence of DC in the stroma of the grafted cornea suggests that they may be mainly responsible for T cell activation and graft rejection since DC are known to be a 100-fold more potent than macrophages as APC.

Adolescent↗
PubMed1999

Enhanced IL-10 and decreased IL-2 production after orthotopic corneal transplantation in mice.

Corneas from mice incompatible at both major histocompatibility complex (MHC) and non-MHC antigens were grafted orthotopically to unmodified and high-risk recipients. Production of interleukin-2 (IL-2) and IL-10 by cells from spleens and draining lymph nodes from corneal graft recipients was determined in vitro. Over 90% of corneal allografts suffered alloantigen-induced inflammatory reaction within the second or third week after surgery. However, only 56 % of grafts in unmodified and 75 % of grafts in high-risk recipients were irreversibly rejected. Cells obtained from draining lymph nodes from the vicinity of the eye of the corneal graft recipients produced significantly elevated amounts of IL-10 and decreased amounts of IL-2. This shift to the Th2 type cytokine response was observed after stimulation of the cells with graft donor MHC antigens, but not after stimulation with donor non-MHC or third-party alloantigens. No changes in cytokine production were detected in spleen. The enhancement of IL-10 production in the vicinity of the eye was a consequence of corneal grafting and did not correlate with the fate of the graft. The results thus show that orthotopic corneal transplantation induces a local shift to the Th2 type cytokine response, which might be considered another factor that contributes to the unique characteristics of the immunity in the eye and to the tolerance of an unusually high percentage of corneal allografts.

Animals↗
PubMed1998

Urocanic acid enhances IL-10 production in activated CD4+ T cells.

The immunosuppressive effects of UV radiation have been well documented. This suppression has been attributed to the action of the cis form of urocanic acid (UCA), a photoproduct of trans-UCA, a natural constituent of the skin. Here, we show that mouse spleen cells preincubated with cis-UCA have a diminished proliferative response to allogeneic cells in MLC and to stimulation with anti-CD3 mAb. Cells preincubated with cis-UCA also had a decreased ability to serve as APC and to stimulate the proliferation of allogeneic lymphocytes in MLC. Simultaneously, the production of IL-2 and IFN-gamma by cells preincubated with cis-UCA was decreased. However, IL-10 gene expression and IL-10 protein secretion by spleen cells stimulated in the presence of cis-UCA were significantly enhanced. The principal cell population displaying the cis-UCA-induced elevated production of IL-10 was CD4+ T cells, which were shown to be a direct target of cis-UCA action. This was also supported by the observation that production of IL-10 by stimulated splenic non-T cells or by macrophages was not altered by cis-UCA. The enhanced production of IL-10 by activated CD4+ T cells may represent a novel pathway of UVB radiation-induced, cis-UCA-mediated immunosuppression. We suggest that the elevated production of IL-10 by activated CD4+ T cells may account for the suppressor T cell phenomena described in UV-irradiated recipients.

Adjuvants, Immunologic↗
PubMed1998

The effect of urocanic acid on graft rejection in an experimental model of orthotopic corneal transplantation in rabbits.

BACKGROUND: Urocanic acid (UCA) is a natural component of the stratum corneum of the skin. It has been described as a photoreceptor for ultraviolet B radiation. UCA is present in the skin as a trans-isomer and undergoes UVB irradiation-dependent isomerization from trans-to cis-isomer. An immunosuppressive effect of irradiated UCA, i.e. a mixture of cis- and trans-isomers, has been demonstrated both in vivo and in vitro. The aim of this study was to evaluate an immunosuppressive effect of irradiated UCA on graft rejection in an experimental model of orthotopic corneal transplantation. METHOD: A commercially available UCA was dissolved in salt solution and irradiated by XeCl excimer laser beam in order to obtain a mixture of cis- and trans-isomers. The immunosuppressive effect of irradiated UCA, compared to controls, unirradiated UCA and salt solution, was evaluated in a high-risk orthotopic corneal transplantation model; the agents were administered subconjunctivally to rabbits. RESULTS: The rejection reaction was observed in all animals. The mean graft survival time in rabbits administered salt solution or unirradiated UCA was 20 days and 22 days, respectively. The irradiated solution of UCA significantly (P < 0.01, Mantel-Cox test) prolonged mean graft survival time to 29 days. CONCLUSION: Subconjunctival administration of irradiated UCA prolonged the graft survival time in comparison with unirradiated UCA or salt solution in recipients in a rabbit transplantation model. Although further studies are necessary, UCA seems to be an effective immunosuppressive drug after corneal transplantation.

Animals↗
PubMed1998

Expression of cytokine receptors on different myeloid leukemic cells.

We have studied the expression of cytokine receptors CD25 (IL-2Ra,55kD), CD116 (hGM-CSRF,145kD), CD117 (CSFR,145kD), CD120a (TNFR,55kD), CD120b (TNFR,75kD), CD121a (IL-1R, type I, 80kD), CD123 (IL-3R), CD124 (IL-4R, 140kD), CD126 (IL-6R, 80kD), CDw127 (IL-7R, 75kD), CDw128 (IL-8R), CD130 (gp130 subunit), CD131 (common beta), CD134 (OX40) and also CD95 (Fas antigen) on the myeloid leukemic cells. Cells from peripheral blood or bone marrow of 30 patients with disorders in myeloid lineage included mostly acute myeloid leukemias (with high leukocyte count and percentage of blasts) were analyzed for the expression of surface membrane molecules by indirect immunofluorescence method evaluated by flow cytometry. The findings indicate that some monoclonal antibodies have a reactivity against cytokine receptors of pathological cells in individual cases, but with very variable qualitative and quantitative (number copies/cell) expression (preliminary results). The leukemic cells demonstrate unique cytokine receptor profiles, which reveal the great diversity of immunophenotypes within the main functional characterization of blood malignancies. The immunophenotype heterogeneity of leukemic cells has proved to be much greater than to match with existing classification criteria. This fact could raise the necessity of further evaluation and specification of cytokine markers of the myeloid acute leukemias. On the other hand, detection of cytokine receptors on the leukemia cells is important for cytokine therapy.

Adolescent↗
PubMed1997

Poly (triethylenglycol monomethacrylate) and poly (glycerol monomethacrylate) cross-linked gel as potential viscoelastics for intraoperative use.

BACKGROUND: The highly swelling poly (glycerol monomethacrylate) gel (polyGLYMA) and hydrophilic polymer poly (triethylenglycol monomethacrylate (polyTEGMA) were tested as potential viscoelastics for intraoperative use in anterior segment surgery. METHODS: PolyGLYMA was implanted into the anterior chamber in 5 rabbits, and 40% polyTEGMA in 16 rabbits. The eyes were enucleated 1 week to 3 months after the operation. The corneal endothelium was examined with specular microscopy, and then the whole eye histopathologically. RESULTS: In all eyes of the polyGLYMA group, the clinical findings were characterized by a marked ciliary injection and severe secondary glaucoma, and the histologic ones by a marked inflammatory infiltration and thickening of Descemet's membrane in the anterior chamber angle. Specular microscopy revealed a decrease in the endothelial cell density and polymorphism of the endothelial cells. In the polyTEGMA group, the anterior segment and the fundus were physiologic all the time, and specular microscopy and histologic findings showed no degenerative and/or inflammatory changes. CONCLUSIONS: PolyGLYMA proved unsuitable for intracameral application in rabbits. The new polymer polyTEGMA is characterized by high biologic tolerance after its implantation into the anterior chamber of rabbits. PolyTEGMA 40% might be considered as a potential viscoelastic material in humans.

Animals↗
PubMed1997

[The significance of gender incompatibility in donors and recipients and the role of minor histocompatibility antigens in corneal transplantation].

AIM: The present study evaluates the ability of single male H-Y antigen to elicit corneal graft rejection or to prime recipient with subsequent induction of second-set corneal graft rejection in mice. Results were compared with the survival rates of orthotopic corneal grafts disparate at multiple minor histocompatibility (H) antigens and with syngeneic grafts. METHODS: A/Ph male or B10.A female and A/Ph female corneas were grafted onto A/Ph female mice. During the fourth week after grafting all acceptors of H-Y disparate grafts received the second corneal graft from the same donor. All grafts were evaluated three times a week during the period of nine weeks. RESULTS: Both first and second orthotopic corneal grafts incompatible at H-Y antigen did not display and sign of rejection reaction during the whole observation period and were accepted indefinitely. The rate of rejection reaction of grafts incompatible at multiple minor H antigens was 83%. Thirty-three percent of these grafts underwent rejection irreversibly. CONCLUSIONS: Single H-Y antigen disparity between corneal graft donor and recipient neither led to rejection of first grafts nor primed recipients as shown by tolerance of 100% of second-set grafts. Experiments demonstrated that incompatibility of sex between donor and recipient does not play role in corneal graft rejection. However, incompatibility at multiple minor H antigens led to the rejection reaction in 83% of first grafts and 33% of these grafts failed.

Animals↗
PubMed1996

Transplantation immunity and tolerance in the eye: rejection and acceptance of orthotopic corneal allografts in mice.

The eye has been considered for a long time as a privileged site, where the normal immune response is not manifested. Using a model of orthotopic corneal allografts in mice we demonstrate that both transplantation immunity and tolerance are expressed in the eye. In two strain combinations, one having genetic disparities at the major histocompatibility complex (MHC) and non-MHC antigens and the other with antigenic differences only in non-MHC antigens, survival of corneal allografts was evaluated in normal unmodified recipients, in recipients presensitized with a skin allograft, and in mice made specifically tolerant to the donor alloantigens. While the corneal allografts in unmodified recipients underwent rejection leading to graft failure in 40-50% of the recipients, all corneal allografts in presensitized recipients were rejected. On the contrary, corneal allografts performed in neonatally tolerant recipients enjoyed survival comparable to that of syngeneic grafts. No significant differences in corneal allograft survival were found between MHC antigen compatible and MHC antigen incompatible strain combinations. The results demonstrate that transplantation immunity and tolerance are efficiently expressed in the eye. Consequently, the local regulatory mechanisms must be responsible for the characteristics of immunity after intraocular immunization and for a high degree of acceptance of corneal allografts in normal recipients.

Animals↗
PubMed1996

Immunosuppressive effect of bovine seminal ribonuclease on a model of corneal transplantation in rabbit.

BACKGROUND: Bovine seminal ribonuclease (BS RNase) was determined to have a specific suppressive effect on the proliferation of T lymphocytes in vitro. Its immunosuppressive effect was proven in skin grafting in mice as well. METHODS: The immunosuppressive effect of BS RNase was evaluated in tissue cultures and on a model of corneal transplantation in rabbits. The penetration of BS RNase into the anterior chamber was detected by immunoblotting of anterior chamber fluid obtained from animals treated either topically or subconjunctivally. RESULTS: In vitro blastic transformation of mouse T lymphocytes was significantly inhibited by BS RNase (concentrations 15-250 micrograms/ml). No such effect was observed on B lymphocytes. In the rabbit model of corneal graft rejection, BS RNase injected subconjunctivally prolonged mean graft survival time significantly (33.4 days) compared with placebo (salt solution; MST 17.7 days). No BS RNase was detected by immunoblotting in anterior chamber fluid after either topical or subconjunctival application. CONCLUSION: BS RNase showed significant immunosuppressive effect both in the blastic transformation test and in the rabbit high-risk model of corneal transplantation. Negative results of anterior chamber fluid immunoblotting indicate poor absorption of the drug.

Administration, Topical↗
PubMed1996

The role of major and minor histocompatibility antigens in orthotopic corneal transplantation in mice.

The mouse model of orthotopic corneal transplantation was used to evaluate the clinical course of corneal graft rejection process. Corneal grafts were placed into eyes of naive, unmodified recipients or recipients presensitized with skin graft two weeks before corneal transplantation. Two strain combinations were used, one with genetic disparity at both major and minor histocompatibility antigens and the other with the difference only at multiple minor histocompatibility antigens. A panel of syngeneic graft recipients served as controls. In naive recipients, rejection reaction was recorded in more than 90% of recipients mostly during the third week after grafting and 40-50% of corneas displayed irreversible failure in both strain combinations. Both MHC compatible and incompatible corneal grafts in all presensitized recipients were irreversibly rejected by a second-set allograft reaction. The results thus show an important role of multiple minor histocompatibility antigens in corneal allotransplantation in mice. In addition, the prompt reaction in presensitized recipients is evidence for expression of allotransplantation immunity in the eye, which has been for a long time considered as a privileged site sequestered from systemic immunity.

Animals↗
PubMed1996

[Ambulatory cataract surgery].

The authors present an account of the experience with the first one hundred out patient cataract surgery which were performed at the Second ophthalmological Clinic in 1993 and 1994. They found that the only absolute contraindication is the need to administer general anaesthesia and they discuss the main problems which ensue from the present state of the health services and society as a whole.

Ambulatory Surgical Procedures↗
PubMed1996

[Phacoemulsification in high myopia].

In 39 eyes of 26 patients with a baseline refraction of -6 to -28 dioptres phacoemulsification with implantation of an intraocular lens was performed. During the 3-23-month follow-up period there was no case of detachment of the retina no development of clinically significant secondary cataract. The resulting refraction of the eyes was +1 to -6 from the intended refraction. In none of the patients deterioration of visually acuity was recorded.

Adult↗
PubMed1994

[Does vascularization and the graft diameter affect the rejection reaction in corneal transplantation?].

The rejection (RR) is one of the most serious complications of perforating keratoplasty (PK). The authors evaluated in a retrospective investigation 316 PK made between 1986 and 1990 at the Second Ophthalmological Clinic in Prague. The authors investigated the number, onset, type of RR and its relation to the character of vascularization and size of the graft. The total number of RR was 66 (20.9%) with a mean onset period of 6.67 months. A significantly higher incidence (p < 0.01) of RR was found in the group of vascularized corneas (28.0%), as compared with corneas without vascularization (14.71%). The difference between groups with a superficial and deep vascularization was not significant. The authors did not find a significant difference in the incidence of RR in PK with a 7 mm diameter of the explant or smaller, as compared with explants larger than 7 mm.

Cornea↗
PubMed1993

Alternatively spliced fibronectin molecules in the wounded cornea: analysis by PCR.

PURPOSE: To determine whether certain fibronectin isoforms participate in corneal epithelial wound healing, the authors used the polymerase chain reaction to detect different splicing patterns of the EIIIA segment of fibronectin mRNA in epithelial scrape-wounded cornea of rats. METHODS: Specific fibronectin cDNA sequences synthesized from rat cornea with total RNA were amplified with various sets of synthetic oligonucleotide primers. RESULTS: The authors detected both the EIIIA+ and EIIIA- fibronectin mRNA isoforms during corneal wound healing. The kinetics of corneal expression of both total fibronectin mRNA and the EIIIA- fibronectin mRNA isoform was polyphasic; an initial decrease was followed by an increase at 45 minutes, a second increase at 2 hours, and a third increase at 4 days after wounding. EIIIA+ fibronectin mRNA, not found in normal cornea, also was detected during healing. CONCLUSIONS: The expression of total fibronectin mRNA and both the EIIIA+ and EIIIA- fibronectin mRNA is upregulated during corneal epithelial wound healing. The expression of EIIIA+ fibronectin mRNA during wound healing, a fibronectin isoform that was highly expressed in embryonic tissue, suggests that this fibronectin isoform is involved functionally in corneal wound healing.

Alternative Splicing↗
PubMed1993

[Malignant intraocular lymphoma].

A thirty-year-old patient irradiated five years previously on account of a cerebral tumour was admitted for pars plana vitrectomy with the diagnosis of bilateral chronic uveitis and secondary glaucoma. The intraocular inflammation was characterized by corneal precipitates, pseudohypopyon, circulating large cell conglomerates in the anterior chamber and a dense whitish infiltration of the vitreous cavity. Because an intraocular malignant lymphoma was suspected, repeatedly a diagnostic pars plana vitrectomy was performed on the right eye and once on the left eye and bilateral actinotherapy was administered. Only the last cytological examination revealed the presence of lymphoma cells. The course of the disease on the two eyes differed. In the right eye despite repeated actinotherapy and repeated pars plana vitrectomy the disease proceeded by infiltration of the retina and the optic disc. In the left eye after par plana vitrectomy the finding on the ocular fundus was permanently without focal changes. An intraocular malignant lymphoma is usually masked by the picture of chronic uveitis. Careful analysis of the case-history, clinical picture and above all the awareness of this life threatening disease, are decisive for establishment of the correct diagnosis.

Adult↗
PubMed1992

Topical cyclosporine A and corneal wound healing.

The effect of 2% topical cyclosporine A (CsA) ointment on corneal epithelial and stromal wound healing was evaluated in a masked, placebo-controlled study in rabbits. The difference in epithelial would healing rate in the treatment and placebo group was not statistically significant. There was also no difference in the values of bursting strength of 2-mm central penetrating wounds and in the measurement of hydroxyproline content in the central corneal buttons from the wounded area in both the groups. Clinical evaluation of the quality of regenerating epithelium, stromal edema, haze, and iritis did not reveal a difference between the two groups. There was a significantly higher incidence of conjunctival injection in the CsA-treated group. We conclude that topical cyclosporine A 2% does not significantly inhibit epithelial or stromal corneal wound healing.

Animals↗