[Unilateral hemiarcus lipoides corneae following filtration surgery].
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Adult↗
Biomedical subjects
A Hueber
Publications and source records attributed to A Hueber.
Retinal tolerance to dyes.
BACKGROUND: Dye solutions for intraoperative staining of epiretinal membranes and the internal limiting membrane improve the visualisation of these thin structures and facilitate their removal. In the present study the authors investigated the effects of indocyanine green 0.05%, trypan blue 0.15%, and patent blue 0.48% on bovine retinal function. METHODS: Bovine retina preparations were perfused with a standard solution and the electroretinogram (ERG) was recorded repeatedly. After recording of stable ERG amplitudes the nutrient solution was substituted by one of the dye solutions. The duration of retinal exposure to a dye solution was varied between 10 seconds and 2 minutes. Thereupon, the preparation was reperfused with standard solution for at least 115 minutes. The percentage of b-wave reduction after exposition was calculated. RESULTS: Reductions of the b-wave amplitude were found for each dye solution tested. The effects after application of patent blue and indocyanine green were completely reversible within the recovery time for an exposure period of 60 and 30 seconds, respectively. The application of trypan blue lead to a loss of the b-wave when the retina was exposed for 15 seconds or longer. This effect was only partly reversible within the recovery time. CONCLUSION: The ERG showed toxic effects of trypan blue after a short period of retinal exposure. The intraocular application of trypan blue should be limited to selected cases. However, intraocular application of indocyanine green and patent blue in a sufficient concentration and taking account of a short period of retinal exposure seems possible.
Animals↗
Lens epithelial cells express CD95 and CD95 ligand treatment induces cell death and DNA fragmentation in vitro.
PURPOSE: Despite advances in intraocular lens design and material, posterior capsule opacification remains one of the major problems in modern cataract surgery. Therefore, the use of antiproliferative agents has been advocated. CD95 ligand (CD95L, Fas, Apo-1) is a death ligand that triggers apoptosis in susceptible target cells. Apoptosis allows for the safe disposal of cells without damaging the surrounding tissue. The goal of this study was to characterize and evaluate CD95L-induced cell death in cultured lens epithelial cells (LEC). METHODS: Expression of CD95 in untreated porcine LEC was investigated by flow cytometry. Cell death after CD95L or CD95 agonistic antibody treatment was assessed by crystal violet assay and DNA fragmentation was measured by comet assay. RESULTS: The presence of CD95 was observed in LEC. CD95L treatment resulted in a time--and concentration-dependent killing of LEC, which was synergistically enhanced by the addition of cyclohexamide. CD95L treatment induced DNA fragmentation. CONCLUSIONS: The present study confirms the use of apoptosis-inducing CD95L in the inhibition of LEC proliferation. Further studies are needed before clinical application of CD95L to inhibit posterior capsule opacification will be feasible.
Animals↗
Apoptosis regulators and their role in tumorigenesis.
It has become clear that, together with deregulated growth, inhibition of programmed cell death (PCD) plays a pivotal role in tumorigenesis. In this review, we present an overview of the genes and mechanisms involved in PCD. We then summarize the evidence that impaired PCD is a prerequisite for tumorigenesis, as indicated by the fact that more and more neoplastic mutations appear to act by interfering with PCD. This has made the idea of restoration of corrupted 'death programs' an intriguing new area for potential cancer therapy.
Animals↗
Multidrug resistance-associated proteins in glaucoma surgery.
BACKGROUND: Multidrug resistance (MDR) describes the phenomenon of cross-resistance between different cytostatic agents which are structurally and functionally dissimilar. Two recently discovered proteins, lung resistance protein (LRP) and the multidrug resistance-related protein (MRP) have been implicated in the development of MDR. Since resistance to chemotherapeutic agents is a common problem in filtration surgery, especially in cases of complicated glaucoma, we decided to investigate the presence of MRP and LRP in surgically removed Tenon specimens from glaucoma patients. METHODS: The presence of MRP and LRP in surgically removed Tenon tissue (n=15) was analyzed by immunohistochemistry. The expression by cultured Tenon fibroblasts was assessed by reverse-transcriptase polymerase chain reaction (RT-PCR) and fluorocytometry. RESULTS: LRP expression was detected in 8 of 10 Tenon specimens. Positive staining for MRP was obtained in 5 of 10 specimens. Negative controls with non-immune mouse IgG did not display any specific staining. RT-PCR and fluorocytometry revealed constitutive expression of MRP and LRP, at the RNA and protein level respectively, that was unaltered by pretreatment of the cells with mitomycin C or 5-fluorouracil. CONCLUSION: Our results demonstrate, that besides P-glycoprotein, other components of the MDR-system are present in conjunctival fibroblasts. Future developments in the use of chemotherapeutic agents in association with of filtration surgery need to take account of the presence of these counteracting mechanisms.
ATP-Binding Cassette Transporters↗
CD95-mediated apoptosis: no variation in cellular sensitivity during cell cycle progression.
Sensitivity of CD95-mediated apoptosis has been reported to vary during cell cycle progression (FEBS Lett. (1997) 412, 91-93). Here, we report that three human glioma cell lines with different p53 status (i) undergo growth arrest and synchronous cell cycle re-entry after prolonged serum deprivation, (ii) do not exhibit cell cycle-related changes in CD95 expression at the cell surface, and (iii) do not exhibit cell cycle-related changes in susceptibility to DC95 ligand-induced apoptosis. In contrast, cell cycle-specific activity was demonstrated for various cancer chemotherapy drugs. Further, CD95 expression and susceptibility to CD95 ligand-induced apoptosis does not vary during cell cycle progression of Jurkat T cells, HeLa cervical carcinoma and HepG2 hepatocellular carcinoma cells. These results do not support a role for the cell cycle phase as an important predictor of vulnerability to CD95-mediated apoptosis.
Antibiotics, Antineoplastic↗
Chemotherapy primes malignant glioma cells for CD95 ligand-induced apoptosis up-stream of caspase 3 activation.
The cytotoxic cytokine, CD95 ligand, is an experimental anti-cancer agent. Here, we describe a novel pathway of drug-mediated augmentation of CD95 ligand-induced apoptosis. We report that prolonged pre-exposure of human malignant glioma cells to different cytotoxic agents, VM26, cytarabine and cisplatin, induces strong sensitization to CD95 ligand-induced apoptosis. CD95 gene transfer does not prevent sensitization, suggesting that sensitization is not mediated by drug-induced CD95 expression. Priming with cytotoxic drugs greatly increases CD95 ligand-induced caspase 3 activity, indicating that the cytotoxic drugs positively modulate the CD95-dependent signalling cascade up-stream of caspase 3 activation.
Antineoplastic Agents↗
The topoisomerase I inhibitors, camptothecin and beta-lapachone, induce apoptosis of human retinal pigment epithelial cells.
The aim of the study was to determine whether the topoisomerase I inhibitors, camptothecin and beta-lapachone, are suitable agents for the adjuvant pharmacotherapy of proliferative vitreoretinopathy (PVR). The effects of the drugs on cultured human retinal pigment epithelial (RPE) cells were examined using growth assays, cytotoxicity assays, single cell agarose gel electrophoresis, in situ DNA end labeling and immunoblot analysis for apoptosis-regulatory proteins. Both agents killed RPE cells in a concentration-and time-dependent manner. Cell death was apoptotic as assessed by single cell agarose gel electrophoresis and in situ DNA end labeling. Camptothecin, but not beta-lapachone, induced accumulation of p53 and the major growth arrest-associated p53 response protein, p21. Both drugs enhanced expression of the proapoptotic BAX protein. Camptothecin, but not beta-lapachone, synergistically enhanced RPE cell apoptosis induced by the cytotoxic cytokine, CD95 ligand (CD95L). This effect was linked to camptothecin-induced inhibition of RNA synthesis. Atypical topoisomerase I inhibitors may be promising agents for the adjuvant pharmacotherapy of PVR. Experimental studies to assess possible ocular toxicity upon local administration and to confirm its therapeutic efficacy in an animal model of PVR are required.
Apoptosis↗
Expression and upregulation of microtubule-associated protein 1B in cultured retinal pigment epithelial cells.
PURPOSE: During routine cell culture and under pathologic conditions, human retinal pigment epithelial (RPE) cells lose epithelial characteristics and change their morphology. In this study, changes in gene expression in RPE cells of different generations were evaluated by polymerase-chain-reaction-based differential display mRNA analysis (DD-RT-PCR). METHODS: Total RNA was prepared from freshly isolated and cultured human RPE cells of passages P0 and P3 and was subjected to DD-RT-PCR. One band with enhanced expression was excised, reamplified, and partially sequenced, using a modified dideoxy chain termination approach. Expression of the corresponding protein was ascertained by immunocytochemical analysis. RESULTS: Differential display RT-PCR showed enhanced expression of a specific RNA in P3 cells compared with that in P0 cells. Sequence alignment revealed 98% identity with the 3' end of the coding sequence of human microtubule-associated protein 1B (MAP1B). Confirmation of induced expression of MAP1B mRNA was obtained by PCR with specific primers and by immunocytochemical analysis in cultured RPE cells and in surgically removed epiretinal membranes from patients with proliferative vitreoretinopathy. No expression of MAP1B mRNA or protein was detected in freshly isolated RPE cells. CONCLUSIONS: Differential display RT-PCR in RPE cells with subsequent sequence analysis allows characterization of the maturation- and differentiation-dependent expression of previously undetected genes and gene products in cultured RPE cells.
Animals↗
Improved subtraction technique in intravenous digital left ventriculography: comparison with radionuclide studies.
Adequate processing of left ventricular angiograms depends on the visualisation of all segments of the ventricular wall. At the same time, subtraction of different images can enhance different heart segments but commercially available methods do not allow simultaneous viewing of several images masked by different processes. Using our software, for each studied frame, a four quadrant display permits the simultaneous visualisation of a mask mode image, a diastolic-systolic difference image, an image obtained by subtraction of a frame at the same cycle time and a composite mask subtracted image. The composite mask image is obtained by weighting three images according to videodensitometric measurements by reference to previously acquired data. This method facilitates contour delineation and computation of the ejection fraction by area-length method. Correlation with radionuclide estimates of left ventricular ejection fraction is higher (n = 60, r = 0.90, SEE = 8%) than using the classical mask mode display (n = 60, r = 0.82, SEE = 11%). In a subgroup of 30 patients the contrast medium was injected in an antecubital vein and the correlation coefficient remained satisfactory (n = 30, r = 0.89, SEE = 7%) when compared with the classical subtraction technique (n = 30, r = 0.70, SEE = 12%). We therefore conclude that the composite mask method gives comparatively similar values for left ventricular ejection fraction to those acquired by radionuclide angiography.
Angiography, Digital Subtraction↗
[Hemolytic anemia and cardiac heterografts. Apropos of 2 cases].
Two cases of severe haemolytic anaemia developed after heterograft valve replacement are reported. In one case haemolysis was caused by prosthetic degeneration; in the other case the heterograft was not altered, but a ventricular septal defect had created a high turbulence around the valve which was in pulmonary position. In both cases anaemia subsided after surgical correction of the abnormalities responsible for periprosthetic turbulence. Haemodialysis can only develop in patients with heterograft valve replacement if a change in blood flow rate occurs around the valve, due to its alteration or to an associated cardiac disease.
Adult↗
[Value of digital subtraction of left ventriculographies by the venous route. Comparison with balanced scintigraphy of the heart cavities].
The development of numerisation material in radiology currently permits to perform usual cardiovascular tests. The authors report a series of 48 patients who benefited from the determination by numerised left ventriculography, of their stroke volume (SV). In 37 cases, the peripheral venous route is used while in 11 cases the central venous route is used, in the pulmonary artery trunk. The SV values obtained with both methods (one advocated by the manufacture and another one developed by the authors), are correlated with the SV values obtained with the isotopic method, used as reference. The correlations are satisfactory, approximately 0.79 for all patients of the study, and markedly improve when the injection of the contrast material is performed in the pulmonary artery (approximately 0.95). The authors conclude that determination of the left ventricle SV by numerisation is an interesting technique in centers where there is no department of nuclear medicine, and is absolutely necessary to complement right catheterisation.
Female↗
[Emergency destruction of the bundle of His by endocavitary electric shock. Apropos of a case of refractory supraventricular tachycardia in a respiratory insufficiency patient].
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Aged↗
Basic fibroblast growth factor mRNA, bFGF peptide and FGF receptor in epiretinal membranes of intraocular proliferative disorders (PVR and PDR).
Basic fibroblast growth factor (bFGF) has been shown to be involved in epiretinal membrane formation in proliferative vitreoretinal disorders. However, up to now, little knowledge exists; as to the actual cellular source of this potent mitogen. We examined 20 epiretinal membranes from patients with proliferative diabetic retinopathy (PDR) (n = 12) and proliferative vitreoretinopathy (PVR) (n = 8) for the presence of bFGF peptide, fibroblast growth factor receptor-1 (FGFR-1) and bFGF messenger ribonucleic acid (mRNA). Using a specific antibody, we detected bFGF peptide in most (8/10) examined PDR membranes and in all (8/8) PVR membranes. Moreover, we found positive staining for the corresponding receptor. Local production of bFGF in epiretinal membranes was confirmed by nonisotopic in situ hybridisation for bFGF mRNA in some (4/7) examined PDR membranes and some (3/4) examined PVR membranes. All membranes which contained bFGF mRNA were also positive for bFGF peptide. In conclusion, bFGF is produced and stored in epiretinal membranes. Together with the corresponding receptor, bFGF may play a role in the auto- and paracrine control of the proliferative processes at the vitreoretinal interface.
Adult↗