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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In order to elucidate the influence of acute ocular inflammation on the aqueous humor dynamics and intraocular pressure (IOP), we carried out argon laser photo-coagulations on the rabbit irises and determined the concentrations of aqueous humor prostaglandins (PGs), cyclic AMP and protein. The IOP changed in a biphasic manner, i.e. initial hypertension and later hypotension. The concentrations of aqueous humor PG E2, PG F2 alpha and protein increased markedly after laser irradiation and then decreased gradually, although the concentrations of PG E2 and protein remained significantly higher than the baseline values at 24 hours after the irradiations. The concentrations of aqueous cyclic AMP of the irradiated eyes and control eyes were 67.8 pmol/ml and 29.3 pmol/ml, respectively. We presumed that the increase in concentration of aqueous cyclic AMP and breakdown of the blood-aqueous barrier by PGs caused the reactive hypotension.
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PMID:[Effects of argon laser irradiation of the iris on the concentration of aqueous prostaglandins and cyclic AMP]. 131 34

Aqueous humor flow was calculated during day-time in 148 healthy volunteers and 75 older patients using the Fluorotron Master II anterior chamber protocol (Coherent, Palo Alto, USA). Healthy volunteers as well as patients had no history of ocular pathology, surgery or laser treatment. Slitlamp examination revealed no ocular pathology. Hypertension, diabetes, local and systemic drug therapy, neoplasia, kidney or liver disease, contact lens and ocular trauma were excluded. Mean age of volunteers was 26.5 +/- 3.8 years; age of patients: 65.5 +/- 10.5 years. Aqueous humor flow during day-time in healthy volunteers in the OD: (mean +/- s.d.) 2.26 +/- 1.0 microliters/min, in the OS: 2.17 +/- 1.0 microliters/min, OS: 1.86 +/- 1.1 Ml/min. Correlation coefficient: r = 0.8. The mean aqueous humor flow in the older patients during day-time: OD: 1.91 +/- 1.1 microliters/min. Correlation coefficient: r = 0.54. The Mann-Whitney-U-test revealed a significant difference when comparing the right eyes of healthy volunteers with the right eyes of patients (p < 0.01). When comparing all left eyes the difference is also significant (p = 0.01). The results of the study underline, that the mean aqueous humor secretion does significantly decrease with age. However, the data show that there is only a slight decrease of flow of approximately 2.5% per decade. From the clinical point of view it should be concluded, that although the aqueous humor secretion does decrease with age, this is not of clinical importance, even in cases of glaucoma surgery.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Does aqueous humor secretion decrease with age? 142 63

Our earlier studies of cataracts in Dahl salt-sensitive (DS) rats suggested the possibility of altered lens ion transport as a contributing factor in cataractogenesis in this genetic model. We also observed that those weanling DS rats with the greatest pressor response to a high salt diet eventually developed cataracts, and that changes in salt intake modified cataract formation. In the present studies, we measured lens 86Rb uptake as an index of sodium-potassium adenosine triphosphatase [(Na+,K+)-ATPase] activity in weanling DS rats before the development of cataracts or sustained hypertension. Additionally, plasma renin activity was measured to indirectly assess our hypothesis that the difference between cataract-prone DS rats and DS rats unlikely to develop cataracts might be a difference in degree of salt sensitivity. At the age of 4 weeks, 50 DS and 25 salt-resistant (DR) rats were given a high sodium diet for 2 weeks, at which time the rats were divided into three groups based on the systolic blood pressure response, that is, cataract-prone DS rats with systolic blood pressure equal to or greater than 155 mm Hg, DS rats unlikely to develop cataracts with systolic blood pressure less than or equal to 125 mm Hg, and DR rats. Lens and aqueous humor Na+ and K+, lens dry weight, and water content were not significantly different among the three groups of weanling rats. Plasma renin activity was lowest in cataract-prone DS rats and low in DS rats unlikely to develop cataracts when compared with values in DR rats.(ABSTRACT TRUNCATED AT 250 WORDS)
Hypertension 1990 Feb
PMID:Lenticular rubidium uptake and plasma renin activity in weanling cataract-prone salt-sensitive rats. 240 57

Carotid artery obstructive disease, although infrequently diagnosed as a primary or contributing cause of neovascular glaucoma, can produce distinctive characteristics. Decreased perfusion of the ciliary body may decrease aqueous humor production. As a result, such eyes with neovascular glaucoma may occasionally be normotensive or even hypotensive. Fluorescein angiography may show an increased arm-to-retina time and leakage from the major retinal arterioles. Panretinal photocoagulation may not eliminate the anterior segment neovascularization because of anterior segment ischemia. Endarterectomy can significantly increase intraocular pressure as perfusion to the ciliary body returns to normal. These characteristics were found in two patients, a 67-year-old woman and a 49-year-old man, with diabetes and hypertension. In both cases cyclocryotherapy significantly reduced the intraocular pressure and the rubeosis iridis regressed.
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PMID:Neovascular glaucoma and carotid artery obstructive disease. 240 76

We report 3 new cases of diffuse infiltrating retinoblastoma, and we review the 21 cases of the literature. Clinical features are typical but must not be confused with uveitis. The average age of onset is about 7 years, later than the usual retinoblastoma. Clinical features associate ocular redness, pseudo hypopion, iris nodules, clusters on the pupil and in the anterior chamber, opacities on the posterior face of the cornea. Hypertension appears resistant to medical treatment. The vitreous is hazy but the retina is still visible. The ophthalmoscopic examination reveals exudates covering the peripheric retina, and gray infiltrated retina. Usually there is no focal tumour mass, but totally diffuse tumoral infiltration. Echographic examination does not reveal calcification as in typical retinoblastoma. Neoplastic cells are demonstrated in anterior chamber paracentesis. Cytologic examination of aqueous humor aspirates may be misinterpreted and should be evaluated carefully. Because of tumor cells seeding, lactate dehydrogenase assay is of diagnostic value, prior to considering definitive therapy. None of the tumors were bilateral. The prognosis after enucleation appears good.
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PMID:[Diffuse infiltrating retinoblastoma]. 269 64

We previously described the Dahl salt-sensitive rat as a potential model of cataractogenesis in which cataract formation is associated with hypertension. Cataractous lesions were characterized by a marked lenticular and aqueous humor electrolyte imbalance. In the present study the effects of chronic dietary sodium restriction on cataract formation were evaluated in salt-sensitive rats to determine whether or not modification of the hypertensive process might reduce the incidence of cataracts in this genetic model. In addition, the possibility that early cataractous lesions in adult hypertensive salt-sensitive rats might be reversed by acute sodium restriction was evaluated. Chronic dietary sodium restriction modified the development of hypertension and prevented cataract formation in salt-sensitive rats. Furthermore, acute dietary sodium restriction (1 week) completely and consistently reversed early cataractous lesions (pinpoint opacities) in adult hypertensive salt-sensitive rats. Both the prevention and reversal of cataracts were associated with normalization of the lenticular and aqueous humor parameters measured. These data suggest that cataractogenesis is not the consequence of sustained arterial hypertension, but rather that initiation of both hypertension and cataract formation in this genetic model may be the result of extracellular fluid volume state.
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PMID:Prevention and reversal of cataracts in genetically hypertensive rats through sodium restriction. 280 92

In previous unrelated studies, we observed a 35 to 50% incidence of cataract formation in several groups of Dahl salt-sensitive hypertensive rats (DS) over a 4-year period. In the present study we evaluated longitudinal changes in blood pressure in DS in which cataracts eventually developed and those in which cataracts did not develop when all animals were maintained on a high sodium diet. Lenses were evaluated by slit-lamp microscopy to determine if cataractous lesions were similar among rats, to classify lesion types, and to define the age at which cataracts were detectable in DS. The possible participation of several cataractogenic risk factors as major influences on cataract formation also was evaluated. Finally, aqueous humor concentrations and lenticular content of sodium and potassium were determined to evaluate the possibility that a defect in ion transport at the lens epithelium and ciliary body might play a role in cataractogenesis in DS, since ion transport defects have been shown to lead to lens opacification in other models of genetic and experimental cataracts. Parallel studies were performed in Dahl salt-resistant control rats (DR). A high incidence of cataract formation was found in DS. Although systolic blood pressure was not consistently greater in adult DS with cataracts compared with values in age-matched DS without cataracts, the initial pressor response to a high salt diet was greatest in weanling DS in which cataractous lesions later developed. Slit-lamp analysis revealed that cataracts in this genetic model were cortical, with one mixed cortical, nuclear lesion. Posterior subcapsular lesions were not observed, suggesting that lesions were not steroid-induced.(ABSTRACT TRUNCATED AT 250 WORDS)
Hypertension 1987 Mar
PMID:Cataracts and hypertension in salt-sensitive rats. A possible ion transport defect. 302 58

In 148 healthy volunteers and 75 older patients the physiological aqueous humor secretion was calculated during the afternoon hours (13.00 to 20.00 hours) using the anterior chamber protocol of Fluorotron Master II (Coherent, Palo Alto, USA). Fluorescein eye drops were applied topically to each eye five times, 5 h before measurements. Healthy volunteers as well as patients had no history of ocular pathology, surgery or laser treatment. Further exclusion criteria were hypertension, diabetes, local and systemic drug therapy, neoplasia, kidney or liver diseases, contact lens, ocular trauma. Mean age of volunteers was 26.5 +/- 3.8 years; mean age of patients was 65.5 +/- 10.5 years. The aqueous humor flow in healthy volunteers (mean +/- standard deviation) was 2.26 +/- 1.0 microliters/min and in the older patients 1.91 +/- 1.1 microliters/min. Correlation coefficient between right and left eyes in the younger volunteers: r = 0.8; in the older patients: r = 0.54. The Mann-Whitney-U-test revealed a significant difference comparing mean aqueous humor flow in healthy volunteers with the mean aqueous humor flow in older patients (P < 0.01). The results in our study underline that the mean aqueous secretion does decrease with age of about 2.5% per decade. However, to date we do not know whether eyes with primary open-angle glaucoma or ocular hypertension show such a decrease in aqueous humor flow with age or whether there is an autoregulation mechanism in eyes with primary open-angle glaucoma that decreases aqueous humor secretion in relation to an increase of outflow facility.
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PMID:[Physiologic aging in aqueous humor minute volume of the human eye]. 781 85

Intravenous fenoldopam, a selective dopamine-1 receptor agonist, was compared with placebo in this randomized, double-blind, two-period crossover study to evaluate its effects on intraocular pressure, aqueous dynamics, and macular blood flow in patients with elevated intraocular pressure or primary open-angle glaucoma. Doses of fenoldopam were titrated up to a maximum of 0.5 microgram/kg/min. Intraocular pressure, measured by pneumotonometry, was the primary outcome variable. Other outcomes included macular blood flow assessed by blue field examination, visual field examined by automated perimetry, aqueous outflow facility measured by tonography, and aqueous humor production determined by fluorophotometry. During infusions of fenoldopam, intraocular pressure increased from a mean baseline level of 29.2 mmHg to a mean maximum level of 35.7 mmHg. During the placebo infusions, pressure increased from a mean baseline of 28.4 mmHg to a mean of 29.0 mmHg at the time point that corresponded to the mean maximum intraocular pressure on the day intravenous fenoldopam was administered, to yield a mean difference in pressure between study days of 6.7 mmHg (P < 0.05). There were no apparent changes in macular blood flow, visual fields, or production or outflow of aqueous humor associated with fenoldopam infusion. The increase in intraocular pressure seen in this population of patients with ocular hypertension during infusions of fenoldopam is consistent with fenoldopam-associated increases in intraocular pressure reported in previous studies of healthy volunteers and of patients with accelerated systemic hypertension. These results further suggest that dopamine-1 receptors play a role in the regulation of intraocular pressure.
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PMID:Effect of intravenous fenoldopam on intraocular pressure in ocular hypertension. 911 57

A 60-year-old woman developed anterior segment ischemia 1 week after an uneventful pterygium excision in the left eye. Corrected visual acuity fell from 20/20 to 20/200. Ophthalmic examination found keratic precipitates on the corneal endothelium, ++ cells in the aqueous humor, and necrosis of the lower half of the iris with posterior synechiae resulting in a fixed and distorted pupil. On therapy of topical corticosteroid eyedrops hourly and atropine eyedrops three times a day, the iridocyclitis resolved in 2 weeks. At the final examination 3 months after the surgery, the corrected visual acuity was 20/20. The atrophy of the lower half of the iris and posterior synechiae in the lower half of the pupil, giving the fixed and distorted pupil, were noted as sequelae. Iris fluorescein angiography revealed filling defects in the lower half of the iris but no leakage from iris vessels. Systemic evaluation was unremarkable except for mild hypertension. Doppler studies of carotid, ophthalmic, and central retinal arteries were normal. Mitomycin C, beta-irradiation and rectus muscle fixation sutures were not used. Only conjunctival dissection or episcleral cauterization were seen as possible causes of interference with the anterior segment blood supply. We believe this is the first report of anterior segment ischemia following pterygium surgery.
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PMID:Anterior segment ischemia following pterygium surgery. 924 17


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