Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The authors have carried out a statistical study on two large groups of patients operated on for cataract and in whom the enzyme alph-chymotrypsin has been used, and the occurrence of ocular hypertension has been examined. One group, which contained 1,003 operations most of which were under the microscope using a firm closure technique, was compared with another group of 324 cases operated under the same conditions but without using the enzyme. In all cases the intraocular pressure was measured 24-48 hours after the operation. The rise in pressure, the rapidity of its development were studied together with its duration and the concentration of the enzyme. In addition these findings were compared with another group of 2,334 eyes operated on several years previously with standard techniques using a less hermetic wound suture, without a microscope, with alpha-chymotrypsin, but whose tensions were controlled from the third week. The results show conclusively that there is a greater frequency of the occurrence of raised intra-ocular pressure when the enzyme is used (40,3%) than when it is not used (25,3%). This ocular hypertension persists in all cases to the end of three weeks. The time of the appearance of the hypertension, the numbers affected and the duration of the intraocular pressure were not significantly meaningful in the statistical analysis.
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PMID:[Enzymatic ocular hypertension: a statistical study (author's transl)]. 14 59

In a retrospective study, 92 patients with ocular hypertension, ie, intraocular pressure of 21 mm Hg or higher, and no evidence of glaucomatous visual field defects, were observed for five years. Visual field defects developed in one or both eyes of 33 patients during the five-year follow-up period, while none were detected in the remaining 59. Values for suspected risk factors, determined at the outset of the follow-up period, were subjected to a multivariate analysis with use of linear discriminant analysis and a multiple logistic function. Models of risk providing maximum separation of the two patient groups (visual field loss vs no visual field loss) found that the risk factors having the greatest significance for prediction of visual field loss included vertical estimates of cup/disc ratio, mean IOP during the period of observation, a positive family history of glaucoma, and age. Factors having the lowest predictive values included IOP response to topical dexamethasone, plasma cortisol suppression, and a history of systemic hypertension.
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PMID:Multivariate analysis of the risk of glaucomatous visual field loss. 46 68

The injection of alpha-chymotrypsin into the posterior chamber of the eye is known to produce an experimental ocular hypertension of long duration in animals. The present study reports the pathological changes which occur in the eye during the first nine months after the ocular injection of alpha-chymotrypsin in rabbits. Six weeks after treatment most of the eyes showed a buphthalmia and an intraocular pressure elevation which varied greatly from animal to animal. The anterior chamber angle of the treated eyes showed a progressive enlargement. Several days after the enzyme injection a transient increase in thickness of the cornea and Descemet membrane was noted. Cupping of the optic disc, characterized by a total disappearance of the optic nerve head fibers and an excavation beginning at margins of the retina appeared after four months and in most cases were present seven months after the treatment. More or less prominent retinal degeneration was also evidenced three months after enzyme injection. The results indicate alpha-chymotrypsin-induced occular hypertension in the rabbit leads after several months to pathological change in the eye analogous to that observed in human glaucoma.
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PMID:[Experimental alpha-chymotrypsin model of glaucoma in the rabbit: histopathological studies (author's transl)]. 52 8

The experiments were prompted by the need felt in pharmacology of eyes with hypertension of easy availability, rather long duration and fairly constant levels, to allow observation of the effects of hypotensive agents and to study their mechanism of action. Single doses of 1 mg Triethyltin, a substance producing a hydrodynamic compromission of the brain, were injected into the anterior chamber of rabbit eyes. A rise in ocular tension, beginning within 24 hours and lasting seven to ten days is obtained in about 70% of eyes. The pressure increase ranged from 12 to 30 mm Hg. Biomicroscopic and histologic examinations evidenced an uveitis-like reaction in the first week after treatment. Neoprene casts evidenced an impaired vascularization in the ciliary processes and choroid. Topical and parenteral administration of the most commonly used antiglaucomatous drugs showed how well this hypertension responded to hypotonizing agents. The occurrence of producing an ocular hypertension in the untreated fellow eye following repeated intra-cameral injections of small dosage (1 microgram) of Triethyltin, every two days for more than one month, in the other eye is described. Hypertension resulted in 40% of eyes.
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PMID:[Experimental triethyltin ocular hypertension. Pharmacological and histopathological studies (author's transl)]. 88 99

Alterations of the retinal nerve fiber layer occur as a result of diseases affecting the anterior visual pathway. Optimal viewing conditions, familiarity with the appearance of the normal nerve fiber layer, precise focus, and a high index of suspicion are necessary for the ophthalmoscopic observation of pathologic alteration in the nerve fiber layer. The observer must learn to differentiate pseudodefects (reflexes) from true defects (areas of nerve fiber layer atrophy). Nerve fiber layer changes appear ophthalmoscopically as generalized attrition, slit defects, sector defects (all types of atrophic change), or changes in the appearance of the nerve fiber layer itself. These alterations, which occur in numerous conditions including congenital hemianopia, ocular hypertension and glaucoma, multiple sclerosis, acute Leber optic neuropathy, trauma, severe hypertension, congenital and heredity optic atrophy, toxic amblyopia, papilledema, retinochoroiditis, and following photocoagulation, may be of critical diagnostic importance.
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PMID:Ophthalmoscopic observation of the retinal nerve fiber layer. 92 96

Pattern electroretinogram (PERG) combined with visual evoked potential (VEP) has become increasingly useful in clinical assessment of the anterior visual pathways. In regard to the PERG dependence on ganglion cell activity, we studied monocular PERG in 36 patients (71 eyes) with intraocular hypertension (6 eyes under topical beta-blockers) and in 10 patients (18 eyes) with advanced glaucoma, to estimate the potential effect of increased IOP on ganglion cells. We recorded simultaneous VEP to evaluate the retino-cortical conduction time. Referring to normal values obtained from 19 eyes (12 subjects), we found clear-cut PERG abnormalities in 20 eyes among ocular hypertensive patients with increased IOP. They were more altered in the advanced glaucomatous group. Two or three control exams were performed in 10 patients every 6 months: however such a short-time follow-up seems too limited to define the ERG prognosis value in this pathology. Comparing the PERG with the clinical routine assessments, we discuss its place in the diagnosis and in the follow-up of patients with ocular hypertension.
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PMID:Contribution of pattern electroretinogram and pattern visual evoked potential in early diagnosis of primary open angle glaucoma. 129 20

Adenosine A1 agonists have been shown to induce a variety of pharmacological effects. In New Zealand White rabbits, the topical administration of 500 micrograms of the relatively selective adenosine A1 receptor agonist R(-) phenylisopropyladenosine (R-PIA) produced a biphasic response in IOP in the ipsilateral eye: an initial ocular hypertension (3.5 +/- 1.4 mm of Hg) at 0.5 hour, followed by significant reduction in IOP (5 to 8 mm of Hg) from 2 to 6 hours postadministration. The IOP response to 50 and 165 micrograms of R-PIA demonstrated that the ocular hypotensive response to R-PIA was dose-related; however, no initial hypertension was observed at these lower doses. The ocular response to R-PIA was primarily unilateral with only a small reduction in contralateral IOP at 1 hour observed in animals treated with 500 micrograms. No significant change in pupil diameter was observed with any dose of R-PIA. Pretreatment with the adenosine antagonist CPT (10 mg/kg; i.p.) significantly inhibited the ocular hypotensive response to R-PIA. However, pretreatment with the cyclooxygenase inhibitor indomethacin (50 mg/kg; i.p.) did not alter the change in IOP induced by R-PIA. The administration of R-PIA once a day for five days demonstrated that tolerance does not develop in rabbits with repeated administration. These data demonstrate that the adenosine A1 agonist R-PIA can lower IOP. The unilateral nature and the inhibition by CPT supports the idea that this response is mediated by adenosine receptors located in the eye.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Ocular hypotensive activity of the adenosine agonist (R)-phenylisopropyladenosine in rabbits. 160 41

A hemorrhage in the anterior chamber is a frequent phenomenon, very often treated too easily. Our investigation followed for 3 years (1985-1987) the way in which hyphema were resorbed after the eye contusions in the patients operated by cataract or glaucoma. The causes of hyphemas, their onset, the aspect of the blood and the resorption period are analyzed. The majority of hyphemas were resorbed in the first 7 days (in the case of contusions 87%, after operation of cataract 84%) but in the glaucomatous patients the resorption in the first 7 days appeared only in 50% of the cases; the blood remained in the anterior chamber in 12.5% of cases even after 21 days. The blood in the anterior chamber is resorbed by the excretory ducts, mainly as intact erythrocytes; in the glaucomatous patients the ducts are altered and the erythrocytes are more difficulty eliminated. The liquid in the anterior chamber is eliminated by the fistulization opening, but the erythrocytes do not pass as they cannot be resorbed in the subconjunctival space. The blood in the anterior chamber of an eye with ocular hypertension (decompensated glaucoma or contusions with hypertension) favours the hematic impregnation of the cornea, and the macrophages loaded with hemosiderin are deposited at the level of the excretory ducts, thus increasing the danger of hemolytic secondary glaucoma.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Hyphema, a risk factor in the glaucomatous eye]. 210 Oct 38

The authors analyze ocular hemodynamics parameters in patients with ocular hypertension who were transferred to glaucoma group during ten-year follow-up. The patients who were transferred to this group were those whose hemodynamic parameters were lower than in the reference group. By the end of the follow-up period a negligible reduction of the hemodynamic parameters was observed in the 'hypertension' group and a statistically significant reduction in glaucoma patients. This lead the authors to a conclusion on the necessity of early prescription of drugs stimulating disordered ocular hemodynamics.
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PMID:[Retrospective analysis of the parameters of ocular hemodynamics in patients with initial open-angle glaucoma]. 226 34

The objective was to study dalargin in experiment and its effect on drainage tracts in norm and with experimental hypertension, modulating secondary glaucoma. Investigations have been made on 82 rabbit eyes. The overall results show, that subconjunctival and electrophoretic dalargin injection of (0.1%-0.2-0.5 ml) causes the expansion of anterior and posterior lymph-drainage tracts of the eye and have hypotensive effect for ocular hypertension and secondary glaucoma.
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PMID:[Control of lymph-drainage tracts of the eye by the use of dalargin]. 227 6


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