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1.
Opt Express ; 30(9): 15365-15375, 2022 Apr 25.
Article in English | MEDLINE | ID: mdl-35473257

ABSTRACT

Total internal reflection fluorescence microscopy (TIRF-M) is widely used in biological imaging. Evanescent waves, generated at the glass-sample interface, theoretically strongly improve the axial resolution down to a hundred of nanometers. However, objective based TIRF-M suffers from different limitations such as interference fringes and uneven illumination, mixing both propagating and evanescent waves, which degrade the image quality. In principle, uneven illumination could be avoided by increasing the excitation angle, but this results in a drastic loss of excitation power. We designed dedicated 1D photonic crystals in order to circumvent this power loss by directly acting on the intensity of the evanescent field at controlled incident angles. In this framework, we used dedicated resonant multi-dielectric stacks, supporting Bloch surface waves and resulting in large field enhancement when illuminated under the conditions of total internal reflection. Here, we present a numerical optimization of such resonant stacks by adapting the resulting resonance to the angular illumination conditions in TIRF-M and to the fluorescence collection constraints. We thus propose a dedicated resonant structure with a control of the absorption during thin film deposition. A first experimental demonstration illustrates the concept with a 3-fold fluorescence enhancement in agreement with the numerical predictions.

2.
Sci Adv ; 6(1): eaau5670, 2020 01.
Article in English | MEDLINE | ID: mdl-31921998

ABSTRACT

Directional cell motility relies on the ability of single cells to establish a front-rear polarity and can occur in the absence of external cues. The initiation of migration has often been attributed to the spontaneous polarization of cytoskeleton components, while the spatiotemporal evolution of cell-substrate interaction forces has yet to be resolved. Here, we establish a one-dimensional microfabricated migration assay that mimics the complex in vivo fibrillar environment while being compatible with high-resolution force measurements, quantitative microscopy, and optogenetics. Quantification of morphometric and mechanical parameters of NIH-3T3 fibroblasts and RPE1 epithelial cells reveals a generic stick-slip behavior initiated by contractility-dependent stochastic detachment of adhesive contacts at one side of the cell, which is sufficient to trigger cell motility in 1D in the absence of pre-established polarity. A theoretical model validates the crucial role of adhesion dynamics, proposing that front-rear polarity can emerge independently of a complex self-polarizing system.


Subject(s)
Cell Adhesion/genetics , Cell Movement/genetics , Cell Polarity/genetics , Cytoskeleton/genetics , Animals , Cell Communication/genetics , Computer Simulation , Cytoskeleton/metabolism , Epithelial Cells/metabolism , Fibroblasts/metabolism , Mesenchymal Stem Cells/metabolism , Mice , NIH 3T3 Cells
3.
Sci Adv ; 5(10): eaaw8651, 2019 10.
Article in English | MEDLINE | ID: mdl-31616784

ABSTRACT

HIV-1 Gag protein assembles at the plasma membrane of infected cells for viral particle formation. Gag targets lipids, mainly PI(4,5)P2, at the inner leaflet of this membrane. Here, we address the question whether Gag is able to trap specifically PI(4,5)P2 or other lipids during HIV-1 assembly in the host CD4+ T lymphocytes. Lipid dynamics within and away from HIV-1 assembly sites were determined using super-resolution microscopy coupled with scanning fluorescence correlation spectroscopy in living cells. Analysis of HIV-1-infected cells revealed that, upon assembly, HIV-1 is able to specifically trap PI(4,5)P2 and cholesterol, but not phosphatidylethanolamine or sphingomyelin. Furthermore, our data showed that Gag is the main driving force to restrict the mobility of PI(4,5)P2 and cholesterol at the cell plasma membrane. This is the first direct evidence highlighting that HIV-1 creates its own specific lipid environment by selectively recruiting PI(4,5)P2 and cholesterol as a membrane nanoplatform for virus assembly.


Subject(s)
Cholesterol/metabolism , HIV-1/physiology , Nanoparticles/chemistry , Phosphatidylinositol 4,5-Diphosphate/metabolism , Virus Assembly , gag Gene Products, Human Immunodeficiency Virus/metabolism , CD4-Positive T-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/virology , Cell Survival , Diffusion , Humans , Jurkat Cells , Sphingomyelins/metabolism , Virion/metabolism
4.
Virus Res ; 171(2): 332-40, 2013 Feb.
Article in English | MEDLINE | ID: mdl-22989508

ABSTRACT

Viral assembly is a key step in the virus life cycle. In this review, we focus mainly on the ability of retroviruses, especially HIV-1, to assemble at the plasma membrane of their host cells. The assembly process of RNA enveloped viruses necessitates a fine orchestration between the different viral components and specific interactions between viral proteins and lipids of the host cell membrane. Searching for a comparison with another RNA enveloped virus, we refer to influenza virus to show how it could share (or not) some common features with HIV-1 assembly since both viruses are believed to assemble mainly in raft microdomains. We also discuss the role of RNA and the cellular actin cytoskeleton in enhancing these viral assembly processes. Finally, based on the literature and on new results we have obtained by molecular docking, we propose another mechanism for HIV-1 assembly in membrane domains. This mechanism involves the trapping of acidic lipids by the viral Gag protein by means of ionic protein-lipid interactions, inducing thereby formation of acidic lipid-enriched microdomains (ALEM).


Subject(s)
HIV Infections/virology , HIV-1/physiology , Influenza A virus/physiology , Influenza, Human/virology , Membrane Microdomains/virology , Virus Assembly , Animals , HIV-1/genetics , Humans , Influenza A virus/genetics , RNA, Viral/genetics , RNA, Viral/metabolism
5.
Eur Biophys J ; 36(8): 973-83, 2007 Nov.
Article in English | MEDLINE | ID: mdl-17576550

ABSTRACT

Electropermeabilisation is a well established physical method, based on the application of electric pulses, which induces the transient permeabilisation of the cell membrane. External molecules, otherwise nonpermeant, can enter the cell. Electropermeabilisation is now in use for the delivery of a large variety of molecules, as drugs and nucleic acids. Therefore, the method has great potential in the fields of cancer treatment and gene therapy. However many open questions about the underlying physical mechanisms involved remain to be answered or fully elucidated. In particular, the induced changes by the effects of the applied field on the membrane structure are still far from being fully understood. The present review focuses on questions related to the current theories, i.e. the basic physical processes responsible for the electropermeabilisation of lipid membranes. It also addresses recent findings using molecular dynamics simulations as well as experimental studies of the effect of the field on membrane components.


Subject(s)
Electromagnetic Fields , Membranes/metabolism , Membranes/radiation effects , Animals , Cell Membrane/metabolism , Cell Membrane/radiation effects , Cell Membrane Permeability/radiation effects , Humans , Lipids/chemistry , Lipids/radiation effects , Membrane Proteins/physiology , Membrane Proteins/radiation effects , Permeability/radiation effects , Protein Conformation/radiation effects
6.
J Nutr Health Aging ; 6(6): 370-4, 2002.
Article in English | MEDLINE | ID: mdl-12459887

ABSTRACT

UNLABELLED: Protein-energy malnutrition is common in the elderly. The relationship between protein-energy malnutrition and lipid status remains uncertain and few studies are available. The aim of this study was to evaluate the lipid status of malnourished elderly subjects recently hospitalized in a geriatric medical care unit. Classical parameters such as total cholesterol, HDL cholesterol, apoproteins A1 et B, vitamins A and E were measured. Particular attention was given to other parameters such as fatty acids. The studied population included 86 elderly subjects. They were divided into two groups, according to serum albumin (alb) and Body Mass Index (BMI). Fifty patients aged 81.5 7.3 years were considered to be well-nourished (WN) with albumin 35 g/l and BMI 21 kg/m2. Thirty six patients aged 84.1 6.6 years were considered to be malnourished (MN) with albumin < 35 g/l and BMI < 21 kg/m2. Our main findings shown significant decrease in all classical lipid parameters : total cholesterol (p< 0.001), HDL cholesterol (p< 0.005), apoproteins A1 (p< 0.001) and B (p< 0.001) in the malnourished group. We found an increase in the rate of v9 fatty acids (p< 0.001 for the oleic acid; p< 0.05 for the eicosatrienoic acid) and also an increase in the triene/tetraene ratio (p< 0.05) as a result of malnutrition. CONCLUSION: Protein-energy malnutrition is accompanied by lipid status alterations.


Subject(s)
Cholesterol/blood , Hospitalization , Lipids/blood , Protein-Energy Malnutrition/blood , Aged , Aged, 80 and over , Apolipoprotein A-I/blood , Apolipoproteins B/blood , Cholesterol, HDL/blood , Female , Humans , Male , Nutrition Assessment , Nutrition Disorders , Serum Albumin/analysis , Vitamin A/blood , Vitamin E/blood
7.
J Fr Ophtalmol ; 24(2): 139-46, 2001 Feb.
Article in French | MEDLINE | ID: mdl-11240484

ABSTRACT

BACKGROUND: The manifestations of the ocular toxicity of systemic corticosteroids include posterior subcapsular cataracts and glaucoma. We describe 14 cases of serous detachment of the macula due to central serous chorioretinopathy in patients given long-term steroid therapy, which may be another potential ocular side effect of corticosteroid. CASES REPORT: The 14 (9 men and 5 women) patients were aged from 39 to 55 year old. Their systemic diseases were allergic thrombopenic purpura, optic neuritis, kidney or heart transplant, Churg and Strauss vasculitis, facial palsy, rheumatoid arthritis, systemic lupus and a kidney tumor. None of the patients had hypertension. RESULTS: Serous detachment occurred between 6 days and 10 years after the start of steroid treatment. The higher the doses, the earlier the onset of ocular disease. All patients were symptomatic, with rapid onset of blurred vision. Serous detachment was bilateral in two cases. The fluorescein angiographic finding was in most cases a single small focal hyperfluorescent leak from the retinal pigment epithelium which appeared early in the angiogram and increased in size and intensity. No diffuse degradation of the retinal pigment epithelium was seen on the fluorescein angiogram. Five patients underwent laser photocoagulation of the leaking area followed by resorption of subretinal fluid. In other patients, the symptoms disappeared as the doses of steroid were reduced. CONCLUSION: The pathogenesis of central serous chorioretinopathy remains unclear and is controversial. Corticosteroids are known to worsen the prognosis of idiopathic central serous chorioretinopathy, and serous detachment has been reported after renal transplantation. In most of these cases, chorioretinopathy was combined with diffuse leakage from the choriocapillaris. We discuss the relationship between steroid therapy and focal leakage as seen in idiopathic central serous chorioretinopathy. In conclusion, we describe 14 cases of central serous retinopathy whose clinical and fluorescein angiography were fairly typical, without obvious diffuse degradation of the retinal pigment epithelium. All these patients had been given long-term steroid therapy for various diseases.


Subject(s)
Adrenal Cortex Hormones/adverse effects , Anti-Inflammatory Agents/adverse effects , Chorioretinitis/chemically induced , Methylprednisolone Hemisuccinate/adverse effects , Prednisolone/adverse effects , Adult , Chorioretinitis/diagnosis , Female , Fluorescein Angiography , Humans , Male , Middle Aged , Retinal Detachment/chemically induced , Time Factors
8.
Biospectroscopy ; 5(2): 101-15, 1999.
Article in English | MEDLINE | ID: mdl-10217329

ABSTRACT

With the aim to perform spectroscopic studies and spectral images inside living cells, a microspectrofluorometer has been designed for two-dimensional spectral imaging in the visible and in the near-UV region. The main advantage of the device relies on its ability to scan the laser beam along one direction of the sample. This scanning is optically coupled with one direction of a bidimensional detector, allowing an instantaneous recording of a one-dimensional spectral image. The overall scanning of the sample is achieved by means of submicrometric displacements of the stage in the perpendicular direction. The main characteristics and performances of the microspectrofluorometer in terms of sensitivity (detection of a few molecules), spatial resolution (0.5 x 0.5 x 1 microm), and spectral resolution (1 nm) are presented. Finally, applications of this new apparatus concerning in situ localization and spectral characterization of two dyes are shown with Drosophila salivary glands (ethidium bromide) and T47D tumor cells (Hoechst 33342).


Subject(s)
Image Enhancement/methods , Microscopy, Confocal/instrumentation , Microscopy, Confocal/methods , Spectrometry, Fluorescence/instrumentation , Spectrometry, Fluorescence/methods , Animals , Breast Neoplasms/pathology , Carcinoma/pathology , Drosophila/cytology , Humans , Salivary Glands/cytology , Sensitivity and Specificity , Tumor Cells, Cultured/pathology , Ultraviolet Rays
9.
Doc Ophthalmol ; 97(3-4): 421-5, 1999.
Article in English | MEDLINE | ID: mdl-10896359

ABSTRACT

This study was conducted to determine whether indirect grid laser therapy is effective in reducing focal diabetic macular edema characterised by focal leaks and hard exsudates involving the para-foveal area (less than 300 microns from the center of the fovea). Since focal coagulation of microaneurysms in such a critical location can be deleterious, indirect grid pattern laser treatment may be used in such cases.


Subject(s)
Diabetic Retinopathy/surgery , Laser Coagulation/methods , Macular Edema/surgery , Retinal Vessels/pathology , Adult , Aged , Aged, 80 and over , Capillary Permeability , Diabetic Retinopathy/complications , Diabetic Retinopathy/diagnosis , Exudates and Transudates , Female , Fluorescein Angiography , Fundus Oculi , Humans , Male , Middle Aged , Retrospective Studies , Visual Acuity
10.
Eur J Biochem ; 249(3): 895-904, 1997 Nov 01.
Article in English | MEDLINE | ID: mdl-9395341

ABSTRACT

We have previously shown that when administered to mice without adjuvant, a chimeric peptide consisting of the fusion peptide F from measles virus protein linked at the C-terminus of a cytotoxic T-cell epitope from the M2 protein of respiratory syncytial virus efficiently primes for an major histocompatibility complex (MHC) class-I restricted cytotoxic T lymphocyte (CTL) response. In this report, we demonstrated by microspectrofluorometry that the fusion-peptide moiety bound to the plasma membrane of living cells. When the fusion peptide was linked to the C-terminus of the CTL epitope, the chimeric peptide (M2-F) adopted a marked beta-sheet conformation. In contrast, when the fusion peptide was linked to the N-terminus of the T-cell epitope (F-M2), the chimeric peptide adopted an alpha-helical conformation in the presence of trifluoroethanol. The immunogenicity of the two chimeric peptides for class-I restricted CTL was also significantly different, the one adopting the alpha-helical conformation being more immunogenic. Probably due to its obvious conversion to an alpha-helical conformation, the F-M2 peptide could have a higher propensity to insert into membranes, as shown by microspectrofluorometry, with a resultant better immunogenicity than the M2-F peptide.


Subject(s)
HN Protein , Recombinant Fusion Proteins/immunology , T-Lymphocytes, Cytotoxic/immunology , Viral Fusion Proteins/immunology , Viral Proteins/immunology , Amino Acid Sequence , Animals , Cell Division , Cell Membrane/chemistry , Cells, Cultured , Circular Dichroism , Epitopes/immunology , Female , Immunization , Measles virus , Mice , Mice, Inbred BALB C , Microscopy, Fluorescence , Molecular Sequence Data , Protein Structure, Secondary , Recombinant Fusion Proteins/chemical synthesis , Recombinant Fusion Proteins/chemistry , Respiratory Syncytial Viruses , Spectrometry, Fluorescence , Spleen , Trifluoroethanol/pharmacology , Viral Envelope Proteins , Viral Fusion Proteins/chemistry , Viral Proteins/chemistry
11.
Am J Pathol ; 151(5): 1215-24, 1997 Nov.
Article in English | MEDLINE | ID: mdl-9358746

ABSTRACT

The hypothesis that tumor growth is angiogenesis dependent has been documented by a considerable body of direct and indirect experimental data. A prerequisite for the development of novel anti-angiogenic agents is the design of drugs that would be active only on those endothelial cells with an angiogenic phenotype. We took advantage of the anti-idiotypic strategy to obtain circulating agonists specific for the vascular endothelial growth factor receptor KDR/flk-1 (J-IgG). They induced in the absence of VEGF cell proliferation in vitro and angiogenesis in the corneal pocket assay either through local or systemic delivery. Intraperitoneal injections of J-IgG in nude mice grafted with a prostatic adenocarcinoma led to tumor enlargement associated with an increase in both tumor vascularization and proliferation. In contrast KDR/flk-1 overstimulation had no detectable effect on normal tissues. These data underline that KDR/flk-1 is a functional marker of the angiogenic phenotype of endothelial cells.


Subject(s)
Endothelium, Vascular/physiology , Neovascularization, Physiologic/physiology , Receptor Protein-Tyrosine Kinases/physiology , Receptors, Growth Factor/physiology , Adenocarcinoma/pathology , Animals , Cell Division/drug effects , Cell Division/physiology , Cell Movement/physiology , Endothelial Growth Factors/pharmacology , Endothelium, Vascular/cytology , Immunoglobulin G/metabolism , Immunoglobulin G/pharmacology , Immunoglobulin G/physiology , Immunoglobulin Idiotypes/metabolism , Immunoglobulin Idiotypes/pharmacology , Immunoglobulin Idiotypes/physiology , Injections , Ligands , Lymphokines/pharmacology , Male , Mice , Mice, Nude , Neoplasm Transplantation , Neovascularization, Physiologic/drug effects , Phenotype , Prostatic Neoplasms/pathology , Receptor Protein-Tyrosine Kinases/metabolism , Receptors, Growth Factor/metabolism , Receptors, Vascular Endothelial Growth Factor , Transplantation, Heterologous , Vascular Endothelial Growth Factor A , Vascular Endothelial Growth Factors
12.
Eur Biophys J ; 25(4): 225-37, 1997.
Article in English | MEDLINE | ID: mdl-9112754

ABSTRACT

The incorporation of 10(-6) M ethidium bromide (EB) was studied in viable Drosophila melanogaster salivary glands with a spatial resolution reaching a few microns3, using a confocal laser microspectrofluorometer designed for spectral analysis. Spectra were recorded with the 514 nm Argon laser line during excitation times of 1 second (20 microW on the preparation) at 5 min intervals for 30 or 60 min, either at points in determined cell sites or serially throughout the cells. The fluorescence intensity time-course indicated that the EB intake was not an all-or-none process, but rather a graded, sensitive indicator of the functional state of the cell. On the micrometer scale, the cytoplasm behaved as an homogeneous substrate with the fluorescence intensity depending on EB intake and intracellular diffusion. In the nucleus, however, localized enhancement of the emission intensity was observed. Spectral analysis allowed us to characterize the interactions. The mean values of lambda max in the cytoplasm (600 nm), in the nucleus (601 nm) and outside the glands (602 nm) were less than for free EB in aqueous solution (630 nm); values of full width at half maximum were between 92 and 96 nm, which is much lower than the 120 nm observed for free EB. The recorded spectra were analyzed using a linear combination of two spectral models, namely free and DNA intercalated EB. In the nucleus, the free EB model spectra was found to represent up to 10% of the recorded spectra whereas it was near zero in the cytoplasm. The present data suggest that the intranuclear concentration of free EB (allowing for its lower fluorescence quantum yield) might be at least equal to that of the bound EB.


Subject(s)
Ethidium , Salivary Glands/cytology , Animals , Cell Survival , Coloring Agents , Cytoplasm/ultrastructure , DNA/analysis , Drosophila melanogaster , Intercalating Agents , Kinetics , Microscopy, Confocal/instrumentation , Microscopy, Confocal/methods , Spectrometry, Fluorescence/instrumentation , Spectrometry, Fluorescence/methods
13.
Diabetes Metab ; 22(4): 268-73, 1996 Jul.
Article in English | MEDLINE | ID: mdl-8767174

ABSTRACT

Since the pioneer work of Michaelson in 1947 reporting that retinal ischemia induces the release of soluble angiogenic compounds, numerous studies have been conducted to identify the molecular structure of such messengers. In the early 1980s, the deciphering of angiogenic factor-signaling pathways and their description in the retina focused attention on growth factors. Vascular endothelial growth factor, the major candidate identified in 1992, induces in vivo angiogenesis and vascular permeability. Its expression is enhanced in vitro by hypoxia and hypoglycaemia; and its immunoreactivity is increased in diabetic patients. A decrease in its bioavailability reduces the intensity of neovascularization.


Subject(s)
Diabetic Retinopathy/physiopathology , Endothelial Growth Factors/physiology , Fibroblast Growth Factor 1/physiology , Fibroblast Growth Factor 2/physiology , Lymphokines/physiology , Neovascularization, Pathologic/physiopathology , Retinal Vessels/physiopathology , Animals , Biological Availability , Humans , Receptors, Growth Factor/physiology , Vascular Endothelial Growth Factor A , Vascular Endothelial Growth Factors
14.
C R Acad Sci III ; 319(5): 411-5, 1996 May.
Article in French | MEDLINE | ID: mdl-8763741

ABSTRACT

We took advantage of the anti-idiotypic strategy to design circulating probes mimicking the biological effects of VEGF (vascular endothelial growth factor) or FGF2 (fibroblast growth factor 2). The activation of the VEGF receptor KDR/flk-1 induced endothelial cell proliferation but not their migration, whereas that of the FGF receptor FGF-R1 gave opposite results. The long lasting delivery of KDR/flk-1 agonists, but not that of FGF-R1, in nude mice grafted with tumor fragments enhanced the tumor volume. Microscopic examination showed an increase in both the vascularization and the proliferation of cancer cells. In contrast, no difference in cell proliferation was observed within normal tissues.


Subject(s)
Adenocarcinoma/pathology , Angiogenesis Inducing Agents/immunology , Antibodies, Anti-Idiotypic/pharmacology , Prostatic Neoplasms/pathology , Animals , Cell Division/drug effects , Cell Movement/drug effects , Endothelial Growth Factors/pharmacology , Fibroblast Growth Factors/pharmacology , Lymphokines/pharmacology , Male , Mice , Mice, Nude , Vascular Endothelial Growth Factor A , Vascular Endothelial Growth Factors
15.
Ophthalmology ; 103(4): 561-74, 1996 Apr.
Article in English | MEDLINE | ID: mdl-8618753

ABSTRACT

BACKGROUND: Florid diabetic retinopathy (FDR) is a rare form of proliferative diabetic retinopathy (PDR) that is characterized by a bilateral rapidly progressive, very severe ischemic retinopathy. Florid diabetic retinopathy was reported to carry a high risk of blindness. This study was conducted to determine whether visual prognosis of FDR can be improved by appropriate photocoagulation and surgical management. METHODS: The authors retrospectively studied 20 patients (40 eyes) who were treated from October 1978 to February 1994. Systemic risk factors, visual acuity, complete ocular examination, and fundus findings, as well as fluorescein angiography, were analyzed with respect to photocoagulation and surgical management. Mean follow-up was 3.6 years. RESULTS: All patients had poorly controlled type I diabetes (mean duration, 13.5 years), which often was associated with systemic complications. Mean initial visual acuity was equal to or better than 20/40 in 32 eyes (80%). During the course of the study, high-risk PDR was observed in 38 eyes (95%) and vitreous hemorrhage occurred in 26 eyes (65%). Extensive full subconfluent panretinal photocoagulation was performed completely in 37 eyes (92.5%). Vitrectomy was necessary in 15 eyes (37.5%). Macular edema was present in 30 eyes (75%). Major complications included retinal detachment that required surgery (2 eyes, 5%) and neovascular glaucoma (2 eyes, 5%). However, final visual acuity was equal to or better than 20/40 in 23 eyes (57.5%) and less than 5/200 in only 4 eyes (10%). CONCLUSION: These results suggest that aggressive treatment of FDR with extensive panretinal photocoagulation and early vitrectomy, when necessary, may result in a much better prognosis than has been reported previously.


Subject(s)
Diabetic Retinopathy/surgery , Laser Coagulation , Retina/surgery , Vitrectomy , Adolescent , Adult , Diabetes Mellitus, Type 1/complications , Diabetic Retinopathy/pathology , Diabetic Retinopathy/physiopathology , Female , Fluorescein Angiography , Fundus Oculi , Humans , Male , Postoperative Complications , Prognosis , Retina/pathology , Retina/physiopathology , Retinal Vessels/pathology , Retrospective Studies , Visual Acuity/physiology
17.
Arch Ophthalmol ; 112(11): 1476-82, 1994 Nov.
Article in English | MEDLINE | ID: mdl-7980139

ABSTRACT

OBJECTIVE: To study the involvement of eight angiogenic growth factors that have been identified so far in the literature, especially vascular endothelial growth factor, in proliferative diabetic retinopathy. METHODS: Samples of neovascular membranes were obtained from diabetic patients; these samples, excised at vitrectomy, were used to study the expression of messenger RNA of the angiogenic factors by using the method of the reverse transcription-polymerase chain reaction. Vitreous aspirates that were taken from diabetic and control patients were used to quantify vascular endothelial growth factor-like activity with a competitive radioreceptor assay. RESULTS: Of the eight angiogenic factors studied, vascular endothelial growth factor was the only one that was always expressed in the samples of neovascular membranes. Furthermore, vascular endothelial growth factor receptor-binding activity was greater in vitreous aspirates that were obtained from diabetic patients than in samples that were taken from control patients (P < .01). CONCLUSION: Vascular endothelial growth factor seems to be an appropriate candidate for mediating retinal diabetic neovascularization.


Subject(s)
Diabetic Retinopathy/metabolism , Endothelial Growth Factors/metabolism , Lymphokines/metabolism , RNA, Messenger/metabolism , Vitreous Body/metabolism , Adolescent , Adult , Aged , Aged, 80 and over , Base Sequence , Cell Membrane/metabolism , DNA Primers , Diabetic Retinopathy/complications , Endothelial Growth Factors/genetics , Female , Humans , Lymphokines/genetics , Male , Middle Aged , Molecular Sequence Data , Polymerase Chain Reaction , Receptor Protein-Tyrosine Kinases/metabolism , Receptors, Growth Factor/metabolism , Receptors, Vascular Endothelial Growth Factor , Vascular Endothelial Growth Factor A , Vascular Endothelial Growth Factors
18.
Pathol Biol (Paris) ; 39(2): 153-6, 1991 Feb.
Article in French | MEDLINE | ID: mdl-2017341

ABSTRACT

A new growth factor, provisionally named vasculotropin (VAS), with a unique specificity for vascular endothelial cells has been purified to homogeneity. VAS is a 45 kDa glycosylated homodimeric protein. Cloning of the VAS gene has evidenced a sequence homology with A and B chains of Platelet-Derived Growth Factor. The receptor on vascular endothelial cells has been shown to be a 180 kDa protein. A 110 kDa receptor has been found on cells that do not respond to the mitogenic effect of vasculotropin, such as lens epithelial cells or corneal endothelial cells.


Subject(s)
Growth Substances/physiology , Growth Inhibitors/physiology , Growth Substances/chemistry , Growth Substances/genetics , Humans , Vascular Endothelial Growth Factor A , Vascular Endothelial Growth Factors
19.
C R Acad Sci III ; 313(1): 21-6, 1991.
Article in French | MEDLINE | ID: mdl-1913246

ABSTRACT

Vasculotropin is a growth factor with a unique specificity for vascular derived endothelial cells. We report that normal human peripheral lymphocytes represent another target for vasculotropin. The mitogenic activity of the medium conditioned by these cells cultured in the presence of Concanavalin A is potentiated by vasculotropin. This effect is exerted more likely through interactions with the soluble mediators rather than through the VAS receptors since VAS binds equally to Concanavalin A stimulated and to unstimulated lymphocytes.


Subject(s)
Growth Substances/pharmacology , Lymphocytes/drug effects , Mitogens/pharmacology , Concanavalin A/analysis , Fibroblast Growth Factor 2/pharmacology , Humans , Lymphocytes/cytology , Vascular Endothelial Growth Factor A , Vascular Endothelial Growth Factors
20.
Biol Cell ; 73(1): 1-6, 1991.
Article in English | MEDLINE | ID: mdl-1726419

ABSTRACT

Angiogenesis is a key step in organ development and remodeling during embryogenesis or tissue regeneration. Some pathological events such as tumor growth or diabetic retinopathy also lead to angiogenesis formation. Several molecules have already been identified as promoting angiogenesis in vivo. Whether their bioactivity is mediated by other angiogenic growth factors or not is still unclear. We identified and purified recently a new angiogenic growth factor. Its unique specificity for vascular endothelial cells led us to provisionally name it vasculotropin (VAS). We describe the biochemical properties of VAS and its biological functions. Structural data showed that VAS is related to the SIS family. In vivo VAS was recognized as an inducer of angiogenesis and vascular permeability. In vitro, despite a moderate action on proliferation, VAS strongly stimulates the cell migration. The screening of the presence of cellular receptors and VAS production showed that the cells which bind VAS do not synthesize it, whereas the cells which synthesize VAS do not bind it. Thus, VAS seems to act through a paracrine pathway. We also present data suggesting that VAS has a lymphokine activity.


Subject(s)
Growth Substances/physiology , Neovascularization, Pathologic , Receptors, Cell Surface/metabolism , Receptors, Cytokine , Receptors, Growth Factor , Amino Acid Sequence , Animals , Growth Substances/isolation & purification , Humans , Molecular Sequence Data , Organ Specificity , Sequence Homology, Nucleic Acid , Vascular Endothelial Growth Factor A , Vascular Endothelial Growth Factors
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