Bascom Palmer Eye Institute, University of Miami, Miami, Florida, USA.Clinical and Experimental Ophthalmology (Impact Factor: 2.35). 06/2013; 42(3). DOI: 10.1111/ceo.12154
We read with interest the article by Zamora-Alejo and colleagues (1) . We laud them for presenting a series of delayed onset hyaluronidase-related complications, and alerting your readership of this potential hazard. Although we concur with their inference of hyaluronidase-induced tissue toxicity, we cogitate that these were type B adverse drug reactions (idiosyncratic) (2) .
Article: Recombinant hyaluronidase: Response[Show abstract] [Hide abstract]
ABSTRACT: We thank Dr Palte et al(1) for their comments on our article.(2) In our series, the patients that were tested for hyaluronidase allergy had negative results to both patch tests and intradermal skin pricks, allowing us to rule out a type IV hypersensitivity or Type B reaction. We still believe that these patients had a form of toxic effect to the hyaluronidase, due to the use of higher concentration (50-250 IU/ml) than normally recommended (15-25 IU/ml). Type A effects are dose-dependent, and toxic effects occur as an exaggeration of the normal therapeutic dose.(3-4.)
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ABSTRACT: Hyaluronidase catalyzes the hydrolysis of hyaluronan polymers to N-acetyl-D-glucosamine and D-glucuronic acid. This enzyme is a dimer of identical subunits. Hyaluronidase has different pharmaceutical and medical applications. Previously, we produced a recombinant hyaluronidase antigenic fragment of Streptococcus pyogenes. This study aimed to improve the protein production and purity of hyaluronidase recombinant protein from S. pyogenes. In addition, the enzymatic activity of this protein was investigated. The expression of hyaluronidase antigenic fragments was optimized using IPTG concentration, time of induction, temperature, culture, and absorbance of 0.6-0.8-1 at 600 nm. Afterwards, the expressed proteins were purified and the enzymatic activity was assessed by turbid metric method. Data indicated that maximum protein is produced in OD = 0.8, 0.5 mM Isopropyl β-D-1-thiogalactopyranoside (IPTG), 37ºC, NB 1.5x, without glucose, incubated for overnight. The enzymatic activity of the recombinant protein was similar to the commercial form of hyaluronidase. The results showed that an antigenic fragment of the recombinant hyaluronidase protein from S. pyogenes has a considerable enzymatic activity. It can be suggested to use it for medical purposes. In addition, applications of bioinformatics software would facilitate the production of a smaller protein with same antigenic properties and enzymatic activity.
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ABSTRACT: In the past decade ophthalmic anesthesia has witnessed a major transformation. The sun has set on the landscape of ophthalmic procedures performed under general anesthesia at in-hospital settings. In its place a new dawn has ushered in the panorama of eye surgeries conducted under regional and topical anesthesia at specialty eye care centers. The impact of the burgeoning geriatric population is that an increasing number of elderly patients will present for eye surgery. In order to accommodate increased patient volumes and simultaneously satisfy administrative initiatives directed at economic frugality, administrators will seek assistance from anesthesia providers in adopting measures that enhance operating room efficiency. The performance of eye blocks in a holding suite meets many of these objectives. Unfortunately, most practicing anesthesiologists resist performing ophthalmic regional blocks because they lack formal training. In future, anesthesiologists will need to block eyes and manage common medical conditions because economic pressures will eliminate routine preoperative testing. This review addresses a variety of topical issues in ophthalmic anesthesia with special emphasis on cannula and needle-based blocks and the new-generation antithrombotic agents. In a constantly evolving arena, the sub-Tenon's block has gained popularity while the deep angulated intraconal (retrobulbar) block has been largely superseded by the shallower extraconal (peribulbar) approach. Improvements in surgical technique have also impacted anesthetic practice. For example, phacoemulsification techniques facilitate the conduct of cataract surgery under topical anesthesia, and suture-free vitrectomy ports may cause venous air embolism during air/fluid exchange. Hyaluronidase is a useful adjuvant because it promotes local anesthetic diffusion and hastens block onset time but it is allergenic. Ultrasound-guided eye blocks afford real-time visualization of needle position and local anesthetic spread. An advantage of sonic guidance is that it may eliminate the hazard of globe perforation by identifying abnormal anatomy, such as staphyloma.
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