Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “RETINAL VESSELS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,333 records · Page 74Linked to original sources
PubMed2006

[Expression and role of endostatin in the retina of oxygen-induced retinopathy mouse model].

OBJECTIVE: To investigate the effect of endostatin on the pathogenesis and development of retinal neovascula animal model of oxygen-induced retinopathy. METHODS: The animal model of oxygen-induced retinopathy was made by subjecting postnatal mice to hyperoxic conditions (5 days) followed by normoxic conditions. Retinal angiogram was taken by using high molecular weight fluorescein-dextran. The degree of hyperoxia-induced neovascularization in serial paraffin cross-sections was quantified by counting the number of vascular cell nuclei on vitreal side of the internal limiting membrane. The expression of ES and VEGF in the oxygen-induced retina was observed by immunohistochemistry. RESULTS: We successfully constructed the oxygen-induced retinopathy mouse model. FITC-dextran retinal angiography indicated that hyperoxia could produce constriction of retinal vasculature and vaso-obliteration or irreversible closure of many capillary channels and eventually result in non-perfused area in the post-area of retina surrounding the optic disk. Relatively, hypoxia could lead to dilation and torsion of retinal vessels. There were averagely 22 neovascular nuclei per cross-section of eyes in the hyperoxia group and less than 3 nuclei per cross-section of eyes in the control group (P < 0.05). The expressions of ES and VEGF in the retina under hyperoxia were stronger than those under normoxia, expecially the expression of VEGF. CONCLUSION: Taking measures to up-regulate the expression of endogenetic endostatin may have the potential for effective treatment of retinal ischemic neovascularization.

Animals↗
PubMed1988

Cryptococcal meningitis presenting as uveitis.

A patient presented with a posterior uveitis. An inferior plaque of retinal exudation was seen. Full investigation failed to establish a cause until six weeks later, when cryptococcal meningitis developed. The patient was immunocompetent. Exudation in relation to retinal vessels is unusual in idiopathic posterior uveitis, and cryptococcosis should be considered in the differential. Diagnosis is by lumbar puncture or vitreous aspiration.

Adult↗
PubMedDate not supplied

[Retinal vascular beta-adrenergic receptors in man].

Beta-blockers are widely used in the primary open angle glaucoma treatment. The molecular mechanism by which these drugs reduce intraocular pressure is essentially based on the blockade of beta-adrenergic receptors localized on the ciliary processes. Vascular effects of beta-blockers, which are difficult to exhibit clinically, have been recently reported for some drugs with intrinsic sympathomimetic activity. In this study, we attempted to investigate the presence of beta-adrenergic specific binding sites on the human retinal vessels, by means of an in vitro autoradiographic technique. These receptors are localized both on arteries and veins; displacement studies indicated that they are mainly of beta-2 subtype.

Adrenergic beta-Antagonists↗
PubMed1984

Binding sites of peanut agglutinin in mammalian retina.

Histochemical studies were carried out of the binding sites of a lectin, peanut agglutinin (PNA), in the mammalian retina, using lectin labeled with either fluorescein or horseradish peroxidase. In all mammalian species examined, monkey, pig, cat and rabbit, the cones were intensely labeled with the lectin but the rods were unlabeled. The cone synaptic pedicles, the inner synaptic layer, the internal limiting membrane and the retinal vessels were also labeled. It is suggested from the specificity of the PNA binding that galactosyl and/or galactosaminyl residues are present in the mammalian cones, but not in the rods.

Animals↗
PubMed2005

Optic disc duplication or coloboma?

AIM: To describe lesions resembling optic disc duplication and highlight their unusual visual fields. The authors also report the first case of pseudo-duplication of the optic disc with overlying retinal nerve fibre layer. METHODS: Retrospective, non-comparative review of case notes. Humphrey visual fields and OCT-3 imaging were performed. RESULTS: All 11 cases represented peripapillary chorioretinal coloboma, some of which lie superior to the optic disc. A double blind spot or superior hemifield defects can be demonstrated by automated visual field testing. CONCLUSION: Clinical examination and identification of bridging retinal vessels from the true optic disc to the second pseudo disc can usually avoid unnecessary invasive and non-invasive investigations.

Adolescent↗
PubMed1992

[Does timolol modify retinal hemodynamics in patients with normal pressure glaucoma?].

In 31 patients with normal-pressure glaucoma, retinal blood flow, diameter of the retinal vessels and velocity were measured with 2-point fluorometry and automatic measurement of the diameters before and after administration of 0.5% timolol over 2 weeks. After timolol therapy the tension was significantly decreased (before therapy: 18.26 +/- 2.50; after therapy: 15.61 +/- 2.56 mm Hg, P < or = 0.01). The arterial and venous diameters and blood flow were nearly unchanged, but a slight increase in the arterial and venous velocity was noted. We conclude that timolol does not significantly influence the retinal hemodynamics in patients with normal-pressure glaucoma.

Adult↗
PubMed1991

Photodynamic retinal vascular thrombosis. Rate and duration of vascular occlusion.

Dye-sensitized photochemical thrombosis is a new method of producing vascular occlusion in the eye for experimental purposes. The rate and duration of photodynamic occlusions of branch retinal vessels was measured in pigmented and albino rat eyes after intravenous injection of the photosensitizing dye, rose bengal. Selected vessels were exposed to focused, white light until vascular occlusion was observed biomicroscopically. A slit lamp was used for a light source in this procedure, allowing adjustment of spot size, shape, and orientation. Arterioles occluded more rapidly than venules, and the time required to produce vascular occlusion decreased when animals breathed pure oxygen administered by face mask. Rose bengal doses of 40 and 80 mg/kg were effective, 20 mg/kg was partially effective, and 1 and 10 mg/kg were ineffective in producing branch arteriole occlusion at a light intensity of 73.5 mW/cm2. The total light energy required to produce occlusion increased from an average of 0.06 J using 80 mg/kg to 0.50 J using 20 mg/kg of rose bengal. Lower light intensities produced vessel occlusion less rapidly (46 mW/cm2) or not at all (17.5 mW/cm2). The rate of retinal arteriolar occlusion was not affected by ocular pigmentation. The duration of branch vessel occlusion depended on length of vessel treated and did not exceed 3 days in arterioles and 4 days in venules. Histologic sections showed discrete areas of retinal and choroidal vascular thrombosis confined to the area of direct light exposure. Choroidal vascular thrombosis and outer retinal damage predominated in eyes treated at low light intensity. Thrombosis usually extended into the deep choroidal vessels in albino but not pigmented eyes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2005

Thrombin inhibitor reduces leukocyte-endothelial cell interactions and vascular leakage after scatter laser photocoagulation.

PURPOSE: Macular edema is one of the most serious adverse effects after retinal scatter laser photocoagulation. It has been suggested that the inflammatory reaction after photocoagulation may be involved in the pathogenesis of macular edema. This study was designed to evaluate quantitatively the inhibitory effects of argatroban, a direct thrombin inhibitor, on leukocyte-endothelial cell interactions and vascular permeability after scatter laser photocoagulation. METHODS: Argon laser photocoagulation was performed in one half of the retina in pigmented male rats (n = 114). Argatroban was administered just before scatter laser photocoagulation. In the other half of the retina, AO leukocyte fluorography was used to evaluate in vivo leukocyte rolling along the retinal vein and accumulation in the retinal capillary bed. The expressions of P-selectin and intercellular adhesion molecule (ICAM)-1 were evaluated by reverse transcription-polymerase chain reaction. Retinal vessel permeability was quantified by using fluorescein isothiocyanate (FITC)-conjugated dextran. RESULTS: Scatter laser photocoagulation caused significant inflammatory leukocyte-endothelial cell interactions in the nonphotocoagulated half of the retina. Treatment with argatroban suppressed leukocyte-endothelial cell interactions. The maximum number of rolling and accumulating leukocytes was reduced by 46.6% (P < 0.01) and 51.4% (P < 0.01), respectively. The expression of P-selectin and ICAM-1 mRNA was suppressed significantly in the argatroban-treated retinas (P < 0.05). Retinal vascular permeability was also suppressed significantly (P < 0.05). CONCLUSIONS: Argatroban suppressed leukocyte-endothelial cell interactions and blood-retinal barrier breakdown after scatter laser photocoagulation, suggesting that argatroban prevents postlaser macular edema.

Animals↗
PubMed1990

Optic disk elevation in Down's syndrome.

Of five children who had Down's syndrome with optic nerve head elevation, without associated intracranial lesions, three underwent enhanced computed tomography for which no abnormalities were found. Partial, complete, or intermittent resolution of the optic disk elevation occurred in three children. In none of the children were retinal vessel dilation, splinter hemorrhages, optic nerve drusen, subsequent optic atrophy, or apparent visual loss noted. All of the children were hyperopic, but only one child had a hyperopia of greater than 3.50 diopters.

Child, Preschool↗
PubMedDate not supplied

A new autosomal dominant vascular retinopathy syndrome.

We describe a new syndrome with autosomal dominant transmission whose most striking feature is vascular retinopathy. The retinopathy is often associated with migraine, Raynaud's phenomenon and mental changes, mainly forgetfulness, aggression and depression. To define this syndrome we collected medical data on 110 family members. General ophthalmological examination and fluorescein angiography were performed in 61 persons. The retinopathy, as diagnosed in 22 persons, is characterized by central and peripheral microangiopathy, areas of capillary non-perfusion, haemorrhages, cotton wool spots and, in a more advanced stage, occlusion of large retinal vessels, which can induce a neovascular response. A vascular occlusive disorder may be the common aetiological factor of the various manifestation of this syndrome.

Adult↗
PubMed1995

Nitric oxide synthase activity and expression in retinal capillary endothelial cells and pericytes.

The purpose of this study was to examine nitric oxide synthase (NOS) expression in the retinal vasculature in vivo and to study nitric oxide (NO) synthesis in vitro in retinal microvascular endothelial cells and pericytes. Immunoreactivity was examined using a polyclonal antibody raised against porcine cerebellar nitric oxide synthase on frozen sections cut from postmortem human retina and trypsin digests of rat retinal vasculature. The synthesis of nitrite, a stable end product from the interaction of NO with molecular oxygen, was measured in culture supernatants of retinal microvascular cells under basal and stimulated conditions. Expression of constitutive NOS (cNOS) in these cells was examined using the polymerase chain reaction (PCR). Strong NOS immunoreactivity was seen in the endothelium of choroidal and retinal vessels. Nitrite synthesis was documented in supernatants from cultured microvascular endothelial cells which increased significantly following exposure to A23187 and cytokines. Nitrite synthesis by pericytes was not detectable under basal conditions or following stimulation with A23187. Bacterial lipopolysaccharide (LPS), a potent inducer of NOS, caused an increase in nitrite concentrations in pericyte supernatants 24 h after stimulation suggesting the presence of inducible NOS (iNOS). PCR amplification confirmed the presence of the cNOS gene in endothelial cells but not in pericytes. Retinal vascular endothelial cells express significant amounts of NOS constitutively in vivo and in vitro which is activated by Ca++. Also, endothelial cells can be stimulated to synthesize iNOS by cytokines. Retinal pericytes too show iNOS activity following exposure to bacterial LPS. These results suggest that the nitric oxide synthase/nitric oxide pathway may be involved in the regulation of microcirculatory haemodynamics in the retina.

Amino Acid Oxidoreductases↗
PubMed2006

Macular and peripheral distribution of ICAM-1 in the human choriocapillaris and retina.

PURPOSE: In order to understand the extent of choriocapillary endothelial cell activation in different topographic regions of the eye, we sought to compare the localization of intercellular adhesion molecule-1 (ICAM-1) in macular and peripheral regions of human eyes. METHODS: Sections of sucrose-embedded human donor eyes that included the macula and ora serrata were evaluated for ICAM-1 and ICAM-2 immunoreactivity with monoclonal and polyclonal antibodies. Patterns of ICAM-1 labeling in peripheral and macular regions were examined in 20 eyes. Morphometric analyses of anti-ICAM-1 labeling intensity in the choriocapillaris were performed using ImageJ software on a series of macular and extramacular punches from nine eyes. Quantitative PCR analysis for ICAM-1 mRNA was performed on the RPE-choroid from the same regions from six of the same eyes, and Western blots of samples treated or untreated with N-glycosidase were performed to compare retinal and choroidal ICAM-1. RESULTS: ICAM-1 labeling of the choriocapillaris was typically more intense in the macula than in the peripheral choroid in human donor eyes (14/20). ICAM-2 was also detected in the choriocapillaris and retinal vessels. Morphometric measurements confirmed a significant macular-extramacular difference in ICAM-1 in six of nine eyes (p<0.05), with 1 of 9 eyes showing the opposite pattern. This pattern was not noted for endogenous alkaline phosphatase or ICAM-2. The opposite pattern was noted in the external limiting membrane (ELM), which exhibited more intense ICAM-1 labeling in the far periphery than in the macula. On Western blots, choroidal ICAM-1 exhibited a greater molecular weight than the retinal form, with most of the apparent weight difference due to N-linked carbohydrate chains. CONCLUSIONS: The regional differences in ICAM-1 distribution in the choriocapillaris may indicate that this region is subject to increased leukocyte trafficking. In view of the role of inflammatory processes in age-related macular degeneration (AMD), we propose that the higher level of ICAM-1 protein in the macular choriocapillaris may impart greater susceptibility of the macula to immune cell-mediated damage in AMD.

Antigens, CD↗
PubMed1988

Polypeptide fraction from bovine factor VIII used in fluorangiography.

We report a new method of fluorangiography employing a polypeptide fraction from bovine factor VIII that has shown remarkable affinity to the endothelial surface of microvessels. Rabbits injected with this compound, labeled with fluorescein isothiocyanate, show a very delayed disappearance time of fluorescence in retinal vessels when compared with those injected with ordinary fluorescein. This allows a good observation of the late time, which is of great diagnostic advantage for several pathological conditions.

Animals↗
PubMed1987

Radiation retinopathy as an experimental model for ischemic proliferative retinopathy and rubeosis iridis.

We produced radiation retinopathy in capuchin monkeys and studied them with fluorescein angiography and light and electron microscopy. The animals were followed up from ten days to 3 1/2 years after radiation in order to determine whether this could provide an experimental model for other chronic ischemic-proliferative retinopathies, such as diabetes. The first change detected after radiation was the focal loss of capillary endothelial cells and pericytes. As the areas of acellular capillaries became confluent, cotton-wool spots became visible ophthalmoscopically. These increased in number and then faded away, leaving large areas of retinal capillary perfusion. Histologic studies showed occlusion first of the deeper, smaller retinal vessels and then gradually of the larger vessels. Intraretinal neovascularization as well as apparent recanalization then developed, but no new vessels extended through the internal limiting lamina into the vitreous. Rubeosis iridis with neovascular glaucoma developed 2 1/2 to 3 1/2 years postirradiation, and vitreous aspirate demonstrated a high level of angiogenic factor.

Animals↗
PubMed1997

The influence of intraocular pressure and systemic oxygen tension on the intravascular pO2 of the pig retina as measured with phosphorescence imaging.

The intravascular oxygen tension (pO2) of the pig retina was determined by measuring the phosphorescence lifetime of an intravenously injected dye. Pseudocolor images of the intravascular retinal pO2 were obtained. The method is noninvasive except for the application of the dye. The measurement system was adapted to a fundus camera. The systemic arterial oxygen pressure (PaO2) as well as the intraocular pressure (IOP) were altered. In the measurements the pO2 of the choriocapillaris was close to the systemic PaO2. Under normoxia, the retinal veins showed a lower pO2 of about 40 mm Hg. We found evidence of an autoregulation of the retinochoroidal pO2. The retina and the optic nerve head showed an autoregulation of the intravascular pO2 at low IOP, but were more sensitive to a moderate elevation of the IOP of about 40 mm Hg, as compared to the choroidal pO2. The pO2 of the choriocapillaris seemed to change little until the considerably high IOP value of about 50 mm Hg was attained. This behavior is due to either the high perfusion reserve capacity of the choroid or to autoregulation. Although our experiments refer to the perfusion of the pig eye, the results provide indirect evidence that even during a glaucoma attack the human choroid might be able to maintain a reasonable oxygen supply to the retina, whereas the intravascular pO2 of the retinal vessels and of the optic nerve head decrease strongly. The adaptation to a fundus camera facilitates a future clinical application if a nontoxic dye can be developed.

Animals↗
PubMed1997

Optometric findings in velocardiofacial syndrome.

Velocardiofacial syndrome (VCFS) is a congenital genetically determined condition with skeletal, heart, and facial anomalies. Almost all children have learning problems, despite an often normal or above average IQ. We have examined 10 children with a prior diagnosis of VCFS. All were mildly to moderately hyperopic. Most had poor accommodation, and convergence was clinically poor. About 30% had tortuous retinal vessels. VCFS may be detected in the optometry clinic, and optometric management may ameliorate the learning problems in some cases.

Abnormalities, Multiple↗
PubMed1978

[Thrombo-obliterative changes in blood vessels of oculo-cerebral location].

The authors report a 46-year-old woman with discrete signs of central nervous system lesions and thrombo-obliterative changes in retinal vessels. There were no circulatory changes in the extremities. The type of vascular retinal changes, maintained patency of ocular and cerebral arteries and slow course suggested the diagnosis of oculo-cerebral form of thrombo-obliterative changes in blood vessels with involvement of the end portions of these arteries.

Brain Diseases↗
PubMed2004

Associations between the metabolic syndrome and retinal microvascular signs: the Atherosclerosis Risk In Communities study.

PURPOSE: To examine the cross-sectional relationship of the metabolic syndrome (hypertension, hyperglycemia, central obesity, and dyslipidemia) and retinal microvascular abnormalities in middle-aged men and women. METHODS: A population-based, cross-sectional study involving 11,265 persons aged 49 to 73 years who had retinal photography from 1993 through 1995. Photographs were graded for presence of retinal microvascular signs (microaneurysms, retinal hemorrhages, arteriovenous nicking, and focal arteriolar narrowing) according to a standardized protocol. To quantify retinal vessel diameters, photographs were digitized and individual arteriolar and venular diameters were measured and summarized. The metabolic syndrome was defined according to the Third Report of the National Cholesterol Education Program Adult Treatment Panel. RESULTS: After adjustment for age, gender, race, education, cigarette smoking and alcohol consumption, persons with the metabolic syndrome were more likely to have retinopathy (odds ratio [OR] 1.68, 95% confidence interval [CI], 1.45-1.96), arteriovenous nicking (OR 1.30, 95% CI, 1.16-1.45), focal arteriolar narrowing (OR 1.24, 95% CI, 1.10-1.38), generalized retinal arteriolar narrowing (OR 1.23, 95% CI, 1.12-1.35), and generalized retinal venular dilatation (OR 1.30, 95% CI, 1.18-1.48) than persons without the metabolic syndrome. Associations for arteriovenous nicking, focal arteriolar narrowing, generalized arteriolar narrowing, and venular dilatation were noted, even in people without diabetes or hypertension. CONCLUSIONS: These data suggest that the metabolic syndrome is associated with microvascular changes in the retina. This finding reflects, in part, the associations of individual syndrome components with retinal microvascular abnormalities.

Aged↗