Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.36 (hyaluronidase)
4,606 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Instillation of sodium hyaluronate into the anterior chambers of enucleated human eyes caused a 65% decrease in outflow facility (from 0.33 +/- 0.16 microliters/min/mm Hg to 0.08 +/- 0.02 microliters/min/mm Hg). Vigorous anterior chamber irrigation, performed either immediately or three hours after introduction of the sodium hyaluronate, failed to relieve this obstruction. However, irrigation with hyaluronidase restored the facility values to baseline. Tying limbal or corneal 9-0 nylon sutures (for example, in cataract surgery), followed by instillation of sodium hyaluronate into the anterior chamber and subsequent irrigation, produced an overall decrease of 76% in outflow facility (final outflow values were 0.08 +/- 0.03 microliters/min/mm Hg in eyes with corneal wounds and 0.08 +/- 0.04 microliter/min/mm Hg in eyes with limbal wounds). Postoperative intraocular pressure should be monitored closely when sodium hyaluronate is used in cataract surgery. Irrigating the anterior chamber with balanced salt solution after using sodium hyaluronate does not eliminate the possibility of severe postoperative glaucoma.
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PMID:Obstruction of aqueous outflow by sodium hyaluronate in enucleated human eyes. 684 58

Seventy-five patients with senile cataract underwent a planned extracapsular cataract extraction. They were randomly divided into two groups, receiving retrobulbar anesthesia (4 ml lidocaine 2% and 250 IU hyaluronidase) with or without adrenaline. Patients in the adrenaline group had the lowest mean intraocular pressure after the retrobulbar injection (p < 0.02) and they required a shorter time of digital bulbar massage to reduce tension before surgery (p < 0.01). They also appeared to have a deeper anterior chamber during the first part of surgery, although the difference was not statistically significant. The duration of postoperative analgesia was significantly prolonged in patients receiving adrenaline. Different mechanisms explaining the effects of adrenaline in retrobulbar anesthesia are discussed.
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PMID:Retrobulbar anesthesia with and without adrenaline in extracapsular cataract surgery. A prospective, randomized, double-blind study. 762 61

Eighteen normal human eye-bank eyes (age: 18-81 years), five fetal eyes (16-24 weeks), 11 primary open-angle glaucoma (POAG) eyes (age: 76-89 years), and two Schnabel's cavernous optic atrophy eyes were examined using a biotinylated-hyaluronan binding protein to study the changes in the distribution of hyaluronic acid (HA) in the fetal, adult and glaucomatous optic nerve head. The vitreous body served as a positive control. Sections treated with Streptomyces hyaluronidase were used to confirm specificity. Monoclonal antibodies to myelin basic protein (MBP) and glial fibrillary acidic protein (GFAP) were used as additional controls. In fetal optic nerve, HA was localized in blood vessels, peripapillary sclera and the pial septae in the retrolaminar nerve. No staining was associated with axons. Staining for MBP was negative. In adults, HA was found surrounding the myelin sheaths in the retrolaminar nerve; staining decreased with age. In contrast, HA staining in myelinated peripheral nerves (e.g. ciliaries) remained unchanged with age. HA also was localized to the adventitia of arteries and veins throughout the posterior segment. Compared to age-matched normal eyes, HA staining was virtually absent around myelin sheaths of the retrolaminar nerve in POAG eyes. Similar changes were not found in other HA positive structures. In Schnabel's cavernous optic atrophy. HA was present in increased amount in the atrophic area, but virtually absent in the remaining retrolaminar nerve. HA staining was invariably positive in vitreous, and Streptomyces hyaluronidase treated sections were negative. In adults, staining of MBP was associated with the myelin sheath in the retrolaminar nerve. In contrast to HA, staining of MBP was unchanged with age and in POAG. In Schnabel's atrophy, MBP staining disappeared only in the atrophic area. HA in the retrolaminar optic nerve appears to be associate with the space-filling matrix between myelin sheaths. HA is not present in the axon bundles prior to myelination of the optic nerve. HA in the retrolaminar optic nerve appears to decrease with age and is further reduced in POAG; however, corresponding changes are not found in MBP or in peripheral nerves. Perhaps, decreased amounts of HA is related to a higher susceptibility to elevated intraocular pressure or to optic nerve atrophy. In Schnabel's cavernous optic atrophy, HA is present in increased amount only in the atrophic area while MBP is markedly decreased, suggesting in situ production of HA in areas of optic nerve atrophy.
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PMID:Hyaluronic acid in the normal and glaucomatous optic nerve. 922 77

To investigate whether the occasional increase in intraocular pressure that may arise following injection of sodium hyaluronan into the anterior segment during intraocular surgery is related to the polymer size of hyaluronan, controlled fragmentation of hyaluronan chains in vitro was obtained using progressive incubation with testicular hyaluronidase. The profile of molecular sizes of the hyaluronan polymers in various preparations was determined using molecular sieve column chromatography. Individual preparations were injected into six rabbit eyes and intraocular pressures were measured every one-half hour for 12 hours. Longer incubations of hyaluronan with hyaluronidase resulted in more extensive degradation with accumulation of shorter chain lengths. In the rabbit, mean intraocular pressure for 12 hours following intracameral injection of hyaluronic acid (HA) is proportional to the polymer size of HA. The occasional elevation of intraocular pressure that occurs following injection of hyaluronan during ophthalmic surgery can be avoided in part by assuring the rapid fragmentation of the large molecular size hyaluronan polymer.
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PMID:Hyaluronan polymer size modulates intraocular pressure. 926 64

We determined the effect of chronic and acute loss of glycosaminoglycans from the aqueous outflow pathway on intraocular pressure (IOP) and outflow facility in the subhuman primate eye. For the study of the chronic effects of the GAGases, cynomolgus monkeys received intracameral injections of hyaluronidase (Streptomyces, 5 or 50 units, n=2) or chondroitinase ABC (0.05 or 0.25 units, n=2) biweekly for 8 months (4 months for each dose). IOP was measured at 3, 7, 10 and 14 days after each injection. Outflow facility (2-level constant pressure) was determined at 2, 4, 6, and 8 months. Monkeys were killed 6 days after the last injection. The changes in the distribution of hyaluronic acid and sulfated proteoglycans in the outflow pathway were examined using substrate-specific histochemical techniques. The acute effects of these enzymes on outflow facilities (30 min or 2 hr after enzyme) were determined in another group of animals (n=4 for each time enzyme-1). IOP and outflow facility were unchanged compared to controls (heat inactivated enzyme) at any time in the chronically or acutely treated monkeys. Hyaluronic acid staining was absent in the outflow pathways of eyes treated chronically with hyaluronidase compared with control eyes, while collagen-associated sulfated proteoglycans were decreased but not completely removed by the chronic chondroitinase ABC treatment. Chronic loss of these glycosaminoglycans from the trabecular meshwork does not appear to contribute to the IOP elevation and decrease in outflow facility that accompanies open-angle glaucoma. Most importantly, no increase in outflow facility was found with acute hyaluronidase or chondroitinase treatment.
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PMID:Intraocular pressure and outflow facility are unchanged following acute and chronic intracameral chondroitinase ABC and hyaluronidase in monkeys. 926 86

We evaluated the effects of three specific glycosaminoglycan-degrading enzymes, chondroitinase ABC, testicular hyaluronidase, and heparinase, on the intraocular pressure (IOP) and the anterior chamber structures of bovine eyes. The anterior segment of freshly enucleated bovine eyes was perfused in a modified organ culture system. After each enzyme solution or its corresponding vehicle was introduced into the anterior chamber, the IOP was monitored for </=6 h. Compared to the control group, the chondroitinase ABC-treated group showed a significant IOP reduction after 1 h of perfusion. Testicular hyaluronidase and heparinase did not show any significant effect. Light microscopy revealed that chondroitinase ABC and testicular hyaluronidase induced detachment of the endothelial cells from trabecular beams in the uveal meshwork. Disruption of the tissues in the juxtacanalicular region and fragmentation of the endothelial cells facing the angular aqueous plexus were observed in the chondroitinase ABC- and heparinase-treated specimens. Electron microscopic study revealed detachment of trabecular meshwork cells from the beams and rupture of the inner wall of the aqueous plexus in all the enzyme-treated eyes. Cellular organelles and architectures were better preserved in chondroitinase ABC-treated eyes than those treated with hyaluronidase and heparinase. These results indicate that chondroitinase ABC has a pronounced effect on the IOP with relatively minor effect on the trabecular meshwork structures.
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PMID:Effects of glycosaminoglycan-degrading enzymes on bovine trabecular meshwork in organ culture. 1992 Apr 91

We report a rare case of a delayed orbital inflammation with raised intraocular pressure as a result of hyluronidase allergy following sub-Tenon's anaesthesia. Here, we have shown evidence to prove the orbital inflammation to be an allergic response to hyluronidase with a skin patch test. This is the first case to our knowledge of a delayed hypersensitivity reaction to sub-Tenon's hyluronidase comprising of an initial exposure to hyluronidase in the fellow eye with no subsequent allergic response, but with a subsequent delayed reaction to hyluronidase during a second eye cataract surgery. This case demonstrates hyaluronidase allergy should be considered as a differential diagnosis among patients presenting with acute post-operative orbital inflammation, even if there is a history of previous exposure to hyaluronidase in the fellow eye with no subsequent allergic response.
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PMID:Orbital inflammation secondary to a delayed hypersensitivity reaction to sub-Tenon's hyaluronidase. 2386 64

Ophthalmic pediatric regional anesthesia has been widely described, but infrequently used. This review summarizes the available evidence supporting the use of conduction anesthesia in pediatric ophthalmic surgery. Key anatomic differences in axial length, intraocular pressure, and available orbital space between young children and adults impact conduct of ophthalmic regional anesthesia. The eye is near adult size at birth and completes its growth rapidly while the orbit does not. This results in significantly diminished extraocular orbital volumes for local anesthetic deposition. Needle-based blocks are categorized by relation of the needle to the extraocular muscle cone (ie, intraconal or extraconal) and in the cannula-based block, by description of the potential space deep to the Tenon capsule. In children, blocks are placed after induction of anesthesia by a pediatric anesthesiologist or ophthalmologist, via anatomic landmarks or under ultrasonography. Ocular conduction anesthesia confers several advantages for eye surgery including analgesia, akinesia, ablation of the oculocardiac reflex, and reduction of postoperative nausea and vomiting. Short (16 mm), blunt-tip needles are preferred because of altered globe-to-orbit ratios in children. Soft-tip cannulae of varying length have been demonstrated as safe in sub-Tenon blockade. Ultrasound technology facilitates direct, real-time visualization of needle position and local anesthetic spread and reduces inadvertent intraconal needle placement. The developing eye is vulnerable to thermal and mechanical insults, so ocular-rated transducers are mandated. The adjuvant hyaluronidase improves ocular akinesia, decreases local anesthetic dosage requirements, and improves initial block success; meanwhile, dexmedetomidine increases local anesthetic potency and prolongs duration of analgesia without an increase in adverse events. Intraconal blockade is a relative contraindication in neonates and infants, retinoblastoma surgery, and in the presence of posterior staphylomas and buphthalmos. Specific considerations include pertinent pediatric ophthalmologic topics, block placement in the syndromic child, and potential adverse effects associated with each technique. Recommendations based on our experience at a busy academic ophthalmologic tertiary referral center are provided.
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PMID:Regional Anesthesia for Pediatric Ophthalmic Surgery: A Review of the Literature. 3067 53


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