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Results for “RETINAL VESSELS”

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PubMedDate not supplied

Retinal vessel changes in a patient with primary systemic nonfamilial amyloidosis.

A case is described that demonstrates retinal vessel changes and suggests the favorable effects of hemodialysis to treat pathology in a patient with primary systemic nonfamilial amyloidosis. A 47-year-old woman diagnosed as having primary systemic nonfamilial amyloidosis at the age of 30 years had linear and dot hemorrhage, venous dilatation, and tortuosity in the right eye. Fluorescein angiography revealed low-density amorphous areas in the walls of dilated veins near the optic disc. These findings diminished with hemodialysis.

Amyloidosis↗
PubMedDate not supplied

Microperfusion studies of normal retinal vessels. D-glucose transport.

An experimental model was developed to study the permeability of individual retinal vessels in vitro using microperfusion techniques adapted from the kidney tubule studies. Inulin was used as the reference tracer and D-glucose as the test tracer. We found a concentration dependent flux of D-glucose from lumen to bath that increased as D-glucose concentrations in the lumen rose. The flattening of the hyperbolic curve at the higher D-glucose concentrations in the lumen appears consistent with the Michaelis-Menten equation (Km = 6 x 10(-3) M).

Animals↗
PubMed2005

Retinal vessel dilation following repletion of vitamin A deficiency.

We hypothesized that because depletion of vitamin A blocks the initiation of phototransduction, such inhibition of functional activation should lead to decrease retinal metabolism and perfusion. In a case study of a vitamin A-depleted patient, we found that retinal vessel diameters, a surrogate measure of retinal perfusion, increased in concert with the restitution of electroretinographic function following vitamin A supplementation. When normalized to conditions after treatment, the relative magnitude of study parameters at presentation were: scotopic electroretinography B-wave amplitude 1.2%, photopic electroretrinography B-wave amplitude 23%, retinal vein diameter 88%, retinal artery diameter 94%. These observations support that activation of the visual process results in increased retinal metabolism and perfusion.

Adult↗
PubMed2006

[Effects of different oxygen inhalation modes on retinal vessels development in neonatal mice].

OBJECTIVE: This study was designed to investigate the effects of different oxygen inhalation modes on retinal vessels development in neonatal mice in order to provide experimental data for proper oxygen therapy for premature infants. METHODS: A total of 144 postnatal day (P) 7 C57BL/6J mice were randomly assigned into 6 groups according to different oxygen inhalation modes (n=24). Experimental group 1 was exposed to 30%, 40%, 50%, 60% and 75% oxygen in turn for one day respectively, followed by room air exposure for 5 days. Experimental group 2 was exposed to 75%, 60%, 50%, 40% and 30% oxygen in turn for one day respectively, followed by room air exposure for 5 days. Experimental group 3 was exposed to 75% oxygen for 5 days, followed by room air exposure for 5 days. Experimental group 4 was exposed to 75% oxygen for 5 days, 50% oxygen for 2 days and 30% oxygen for 2 days, then room air exposure for 6 days. The supplemental 75% oxygen and room air recovering was performed alternately for the mice in Experimental group 5 for 3 times and then room air exposure for 5 days. The Control group was exposed to room air for consecutive 10 days. The retinal vascular development and proliferation were evaluated by the retinal flat-mounts (ADPase stained retina) and cross-section. RESULTS: The peripheral vascular pattern was clear, and a few avascular areas were seen in the Control group at P12. At P14 the avascular area disappeared. At P17, the entire vascular pattern became completely normal. In the Experimental groups 1, 3 and 5, the central vessels became tortuous and constricted and the central avascular area increased at P12. At P14, neovascularization was seen peaking at P17 in the Experimental groups 1, 3 and 5. In the Experimental group 4, the central avascular area increased and neovascularization was seen at P14, but the central avascular area was reduced and abnormal neovascularization disappeared, with slight constriction of the deep vessels, at P17. Five days later the vascular pattern became almost normal in the Experimental group 4. The retinal vascular form of the Experimental group 2 was similar to that of the Control group. The average number of neovascular nuclei extending into the vitreous per cross-section in the Experimental groups 1, 2, 3, 4, and 5 and the Control group was 49.50 +/- 1.36, 5.17 +/- 0.67, 47.68 +/- 4.70, 5.74 +/- 2.37, 29.15 +/- 2.48, and 1.22 +/- 0.20 respectively. There were significant differences between the Experimental groups 1, 3, 5 and the Control group (P < 0.05). CONCLUSIONS: The effects of different oxygen inhalation modes on the retinal vessels development in neonatal mice were different. The obvious fluctuation of inhaled oxygen concentration and abrupt stop of supplemental oxygen after high levels of supplemental oxygen may severely affect the development of retina vascular, leading to the pathologic changes similar to retinopathy of prematurity.

Animals↗
PubMedDate not supplied

[Results of fraxiparin and ticlid therapy of acute retinal vessels occlusion].

Out of 78 patients with occlusive processes in retinal vessels aged 22-78 years, 28 were treated by combined therapy including heparin (group 1, controls) and for the rest 54 (test group) heparin was replaced by fraxiparin. Fraxiparin is a low-molecular heparin administered parabulbarly in a dose of 0.07 ml with 0.03 ml isotonic sodium chloride. Forty-two out of 54 patients in the test group were administered ticlopedin (ticlide), a disaggregant, in a daily dose of 250 mg (1 tablet) for 1 month; blood aggregation and lacrimal fluid coagulation and fibrinolytic activities were monitored over the course of treatment. Fraxiparin sooner improved visual acuity and caused a lesser number of side effects: in group 1 visual acuity improved in 45.8% and did not change or deteriorated in 54.2%, whereas in the fraxiparin group these values were 68.58 and 31.42%, respectively. Ticlide decreased the risk of repeated occlusions, which occurred in 4 patients vs. 11 in the control group, including those presenting as myocardial infarctions and brain strokes.

Acute Disease↗
PubMedDate not supplied

[Retinal vessels before and after photocoagulation in diabetic retinopathy. Determining the diameter using digitized color fundus slides].

BACKGROUND: Retinal vessel diameter is an important parameter in blood flow analysis. Despite modern digital image technology, most clinical studies investigate diameters subjectively using projected fundus slides or negatives. In the present study we used a technique to examine vessel diameters by digital image analysis of color fundus slides. We investigated in a retrospective manner diameter changes in twenty diabetic patients before and after panretinal laser coagulation. MATERIAL AND METHODS: Color fundus slides were digitized by a new high resolution scanning device. The resulting images consisted in three channels (red, green, blue). Since vessel contrast was the highest in the green channel, we assessed grey value profiles perpendicular to the vessels in the green channel. Diameters were measured at the half-height of the profile. RESULTS: After panretinal laser coagulation, average venous diameter was decreased, whereas arterial diameter remained unchanged. There was no significant relation between the diameter change and the number of laser burns or the presence of neovascularization. CONCLUSIONS: Splitting digitized images into color planes enables objective measurements of retinal diameters in conventional color slides.

Adult↗
PubMed1999

In vivo measurement of the oxygen saturation of retinal vessels in healthy volunteers.

A new method for the spatially resolved measurement of the oxygen saturation of retinal vessels is described. Imaging spectrometry was used for both measurements of transmission and reflectance spectra of whole blood in cuvettes as well as for fundus reflectance spectra. A model was developed for the calculation of the oxygen saturation, valid in the wavelength range between 510 nm and 586 nm, in that the internal reflectance is constant and only the transmitted light depends on layer thickness and hematocrit. Altogether 265 measurements were performed in different number at 30 eyes. In each measurement, the oxygen saturation was simultaneously determined for 193 locations along a line of 1.5 mm at the fundus. The mean oxygen saturation in retinal arteries was (92.2 +/- 4.1)% and (57.9 +/- 9.9)% in retinal veins. The mean retinal arterio-venous difference of the oxygen saturation was (35.1 +/- 9.5)%. The venous oxygen saturation depended on distance from the optic disc. The measured mean of the arterio-venous difference of the oxygen saturation corresponded well to the value of the brain (34%). The utilization of oxygen in the temporal quadrants (inferior: 39.4 +/- 10.4%) is significantly (p = 0.05) higher than in the nasal quadrants (inferior: 31.3 +/- 6.7%).

Adolescent↗
PubMed1991

[A case of facioscapulohumeral muscular dystrophy with infantile spasms, sensorineural deafness and retinal vessel abnormality].

We report an 18-year-old female with facioscapulohumeral dystrophy (FSHD), who had sensorineural deafness, retinal vessel abnormality, mental retardation, and epilepsy. She had infantile spasms at 6 months of age. Muscle atrophy and weakness of facial muscles were first noticed at 3 years of age. From 10 years of age, she had rapidly progressive generalized muscle weakness especially of facial, neck and truncal muscles with marked lordosis. Although mental retardation is commonly complicated with FSHD, infantile spasms or epilepsy has never been reported. Not only mental retardation but epilepsy may be one of the central nervous system symptoms in a systemic disorder, FSHD.

Adolescent↗
PubMed1986

Measurements of retinal microcirculation in retinal vessel occlusion before and after treatment.

Blood flow, arterial velocity, and vascular diameter were measured in patients with retinal vessel occlusion before and after treatment, especially after light coagulation. The mean values in the patient group showed significantly reduced blood flow and velocity compared to the normal group. The mean group difference before and after therapy revealed that while there is an increase in blood flow after treatment, the normal value is not reached. Individual patient values indicated both increased and decreased blood flow and velocity after treatment as compared with the values before therapy. There are various stages in microcirculatory disease and the microcirculation also behaves differently after treatment, which could be observed by measurement in vivo of the physiological flow parameters.

Adult↗
PubMed2001

Vasorelaxant effects of racemic betaxolol and its R- and S- isomers on bovine retinal vessels.

PURPOSE: RS-Betaxolol (equimolar R- and S- isomers) lowers intraocular pressure and dilates precontracted retinal and posterior ciliary arteries in vitro. Betaxolol's vasorelaxant effect is thought to involve the inhibition of calcium influx into vascular smooth muscle and is unrelated to its stereoselective beta-adrenergic blocking action. The authors assessed the vasodilatory effect of RS-betaxolol on different diameters of bovine retinal arterioles and venules, and these responses were compared with the responses induced by R- and S-betaxolol isomers in vitro. METHOD: In-vitro preparations of the bovine retinal microcirculatory system were perfused continuously with oxygenated, heparinized physiological salt solution at 37 degrees C. Diameters of retinal arterioles and venules were measured using video imaging. The retinal vessels were preconstricted with 40 mM KCl, and concentration-response curves for vasodilation were obtained for RS-betaxolol, R-betaxolol, and S-betaxolol. RESULTS: Baseline diameters of first-order (A1) and second-order (A2) branches of retinal arterioles were 50 +/- 0.6 microm and 39 +/- 1 microm, respectively (n = 20), whereas diameters of first-order (V1) and second-order (V2) branches of venules were 75 +/- 0.8 microm and 50 +/- 0.4 mM, respectively (n = 20). The diameters of all sizes of retinal arterioles and venules were significantly reduced (i.e., vasoconstricted) in the presence of 40 mM KCl (n = 20). These preconstricted vessels were relaxed in a dose-dependent manner by cumulative additions of RS-betaxolol, R-betaxolol, and S-betaxolol. The dose-response curves of these compounds were not significantly different. CONCLUSION: RS-Betaxolol, R-betaxolol, and S-betaxolol were equiactive and produced concentration-dependent vasodilatation of all sizes of retinal arterioles and venules studied.

Adrenergic beta-Antagonists↗
PubMed2006

Retinal vessel diameters and obesity: a population-based study in older persons.

OBJECTIVE: Obesity is linked with large vessel atherosclerosis and diabetes. Its association with microvascular changes is less clear. We investigated the associations among retinal vessel diameters, vessel wall signs, and BMI in an older population. RESEARCH METHODS AND PROCEDURES: Retinal photographs were taken on 3654 persons aged 49+ years at baseline of the Blue Mountains Eye Study in Australia. Arteriolar and venular diameters were measured from digitized retinal photographs of the right eyes. BMI was calculated as weight (kilograms)/height (meters2). Incident obesity was defined in persons with BMI < or = 30 at baseline but > 30 after 5 years. A significant weight gain was defined as an increase in BMI of 2+ SDs (4 or more units) over the 5-year period. RESULTS: At baseline, mean BMI was 26.1 (+/-4.6) in this population. At 5-year examinations, 177 (10.0% of 1773 at risk) developed incident obesity, and 136 (6.4% of 2143 at risk) had significant weight gain. After adjusting for age, sex, smoking, triglyceride levels, and mean arterial blood pressure, persons with wider retinal venular diameters had a higher risk of incident obesity (odds ratio, 1.8; 95% confidence interval, 1.0 to 3.1, comparing the highest with lowest venular diameter quintiles) and significant weight gain (odds ratio, 1.7; 95% confidence interval, 0.9 to 3.2). These associations were attenuated with further adjustment for baseline BMI. Arteriolar diameter was unrelated with baseline or change in BMI. DISCUSSION: Wider retinal venular diameter is associated with risk of obesity, independent of hypertension, diabetes, lipids, and cigarette smoking. These data may support a role for impaired microvascular function in the course of weight gain.

Aged↗
PubMed2006

Comparison of retinal vessel measurements in digital vs film images.

PURPOSE: To compare central retinal artery equivalents (CRAE) and central retinal vein equivalents (CRVE) from vessels measured from images captured with a digital camera and digitized images taken with a film camera. DESIGN: Comparison of techniques. METHODS SETTING: Clinic. PATIENTS: A total of 75 eyes of 48 adults. OBSERVATION PROCEDURES: Gradings of retinal vessel diameters from images produced by using two photographic techniques: directly from a 45 degrees digital camera and digitized by scanning from a 30 degrees film-based camera. MAIN OUTCOME MEASURE: Differences in CRAE and CRVE from two types of images. RESULTS: CRAE and CRVE were highly comparable between the two techniques with correlation coefficients of 0.88 and 0.87, respectively. CONCLUSION: Estimates of CRAE and CRVE from measurements taken from digitally captured and digitized film-based images were highly comparable. It is likely that inferences about factors associated with retinal vessel diameters will be unbiased by the method of imaging.

Adult↗
PubMed2005

[Tortuous retinal vessels in neurofibromatosis type 1].

CASE REPORT: We report a 4-year-old patient with neurofibromatosis type 1 (NF-1) who had tortuous retinal vessels of first, second and third order which ended in a corkscrew appearance. DISCUSSION: Vascular retinal abnormalities can be present in patients with NF-1.

Child, Preschool↗
PubMed1994

Tortuosity of the retinal vessels in Aarskog syndrome (faciogenital dysplasia).

Aarskog syndrome (faciogenital dysplasia) is a genetic growth disorder characterized by short stature, cryptorchidism, shawl scrotum, and dysmorphic facial features. Ophthalmic findings include hypertelorism, blepharoptosis, strabismus, and ophthalmoplegia. The authors report a patient with Aarskog syndrome and bilateral retinal vessel tortuosity. This is the first retinal anomaly associated with Aarskog syndrome.

Abnormalities, Multiple↗
PubMed1995

A new approach for detecting the position of retinal vessels and calculating their diameter on the basis of dynamic spectral analysis.

Fast adaptive algorithms were used for the detection of retinal vessels and for pre-processing the signals. By using different methods of dynamic spectral analysis, the local frequency of the vessels was determined. On this basis a method of calculating the diameters of the vessels was constructed; it is robust in relation to disturbances in the domain of the edges.

Algorithms↗