Myocardial ischemia and reperfusion: The role of oxygen radicals in tissue injury

Thrombolytic therapy has gained widespread acceplance as a means of treating coronary artery thrombosis in patients with acute myocardial infarction. Although experimental data have demonstrated that timely reperfusion limits the extent of infarction caused by regional ischemia, there is growing evidence that reperfusion is associated with an inflammatory response to ischemia that exacerbates the tissue injury. Ischemic myocardium releases archidonate and complement-derived chemotactic factors, e.g., leukotriene B 4 and C 5a , which attract and activate neutrophils. Reperfusion of ischemic myocardium accelerates the influx of neutrophils, which release reactive oxygen products, such as superoxide anion and hydrogen peroxide, resulting in the formation of a hydroxyl radical and hypochlorous acid. The latter two species may damage viable endothelial cells and myocytes via the peroxidation of lipids and oxidation of protein sulfhydryl groups, leading to perturbations of membrane permeability and enzyme function. Neutrophil depletion by antiserum and inhibition of neutrophil function by drugs, e.g., ibuprofen, prostaglandins (prostacyclin and PGE 1 ), or a monoclonal antibody, to the adherence-promoting glycoprotein Mo-1 receptor, have been shown to limit the extent of canine myocardial injury due to coronary artery occlusion/reperfusion. Recent studies have challenged the hypothesis that xanthine-oxidase-derived oxygen radicals are a cause of reperfusion injury. Treatment with allopurinol or oxypurinol may exert beneficial effects on ischemic myocardium that are unrelated to the inhibition of xanthine oxidase. Furthermore, the human heart may lack xanthine oxidase activity. Further basic research is needed, therefore, to clarify the importance of xanthine oxidase in the pathophysiology of reperfusion injury. Current data are highly suggestive of a deleterious role of the neutrophil in organ reperfusion and justify consideration of the clinical investigation of neutrophil inhibitors in patients receiving thrombolytic agents during the evolution of an acute myocardial infarction.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44595/1/10557_2004_Article_BF00133206.pd

A prospective, randomised comparison of single and three piece acrylic foldable intraocular lenses

Aims: To compare the postoperative performance of single and three piece acrylic foldable intraocular lenses (IOLs). Methods: 20 patients underwent bilateral cataract surgery with a single piece SA30AL IOL in one eye and a three piece MA30BA IOL in the other eye. The eyes were randomly assigned to either a single or three piece lens. The amount of IOL decentration and tilt, area of anterior capsule opening, and degree of posterior capsule opacification were measured using the Scheimpflug anterior segment analysis system (Nidek EAS-1000). Visual acuity and contrast sensitivity were examined. Measurements were performed by masked examiners before and 1 day, 1 week, 1, 3, 6, and 18 months after surgery. Results: There were no significant differences between the two groups (p>0.05, paired t test) in the amount of IOL decentration, IOL tilt, area of anterior capsule opening, degree of posterior capsule opacification, best corrected visual acuity, and contrast sensitivity throughout the 18 month follow up period. Conclusion: The single and three piece acrylic foldable IOLs are equally stable in the eye after surgery

Risk factors for corneal endothelial cell loss by cataract surgery in eyes with pseudoexfoliation syndrome

Yumi Hasegawa,1,2 Ryohei Nejima,1 Yosai Mori,1 Toshihiro Sakisaka,1 Keiichiro Minami,1 Kazunori Miyata,1 Tetsuro Oshika2 1Miyata Eye Hospital, Miyazaki, 2Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan Purpose: The aim of this study was to investigate the factors associated with decreases in corneal endothelial cell density (ECD) resulting from cataract surgery in eyes with pseudoexfoliation syndrome (PEX). Methods: The clinical records of 78 eyes of 78 patients with PEX who had undergone cataract surgery were reviewed. ECD was measured preoperatively and at 3 months postoperatively with specular microscopy. Multiple regression analysis was used to assess the factors that were significantly related to the rate of ECD loss. Explanatory variables included age, preoperative ECD, pupil diameter, cataract grade, concomitance of glaucoma or diabetes mellitus, preoperative anterior chamber depth, surgery time, total time and power of ultrasound, performance of intraoperative pupillary enlargement manipulation, and postoperative aqueous flare intensity at 1 week and 1 month. Results: ECD before and after surgery was 2,464±337 cells/mm2 and 2,400±347 cells/mm2, respectively, with an ECD loss rate of 2.6%±5.1% (mean ± SD). Multiple regression analysis revealed that ECD loss was significantly associated with the cataract grade (P=0.019) and preoperative anterior chamber depth (P=0.023). Conclusion: With modern small incision cataract surgery, the ECD loss varied with surgical invasions due to severe cataract and shallow anterior chamber, and the presence of PEX was least affected. Keywords: pseudoexfoliation syndrome, corneal endothelial cell loss, cataract surger

Clinical utility of antimicrobial susceptibility measurement plate covering formulated concentrations of various ophthalmic antimicrobial drugs

Norihiko Tou,1 Ryohei Nejima,2 Yoshifumi Ikeda,3 Yuichi Hori,4 Kaoru Araki-Sasaki,5 Kazunori Miyata,2 Yoshitsugu Inoue,3 Akihiko Tawara1 1Department of Ophthalmology, University of Occupational and Environmental Health, Fukuoka, 2Miyata Eye Hospital, Miyazaki, 3Division of Ophthalmology and Visual Science, Faculty of Medicine, Tottori University, Tottori, 4Department of Ophthalmology, Toho University Sakura Medical Center, Chiba, 5Ideta Eye Hospital, Kumamoto, Japan Purpose: The purpose of this study was to evaluate the clinical utility of SG17, an ophthalmic antimicrobial susceptibility measurement plate.Design: This was a multicenter, retrospective, observational study.Patients and methods: Using clinical isolates from patients with ocular infections, drug susceptibility testing using the Clinical Laboratory and Standards Institute standards was routinely conducted at five facilities. The minimum inhibitory concentrations of the isolated strains were determined using SG17 at the Research Foundation for Microbial Diseases of Osaka University. The records of antimicrobial drugs used and the therapeutic course were evaluated for all cases. The susceptibility results from SG17 and routine methods used at each facility were compared.Results: A total of 112 bacterial strains were isolated from 92 patients. Of these cases, keratitis was the most common (52.2%), followed by conjunctivitis (21.7%) and others (26.1%). Principal signs and symptoms resolved in all patients, indicating that therapeutic effects had been achieved. With SG17, drug susceptibility was determined in 98.9% of isolates compared with 30.4% of isolates determined using conventional methods. By adapting the Clinical Laboratory and Standards Institute standards to SG17 results, we found that 91.3% of patients were susceptible and 7.6% were resistant. In five patients, drugs with a resistant evaluation were initially administered with no effect, and the patients were then switched to drugs with a susceptible evaluation with final resolution, indicating agreement of clinical results with SG17.Conclusion: SG17 can be used to determine drug susceptibility to antimicrobial agents currently used in ophthalmic practice. SG17 is useful for selecting antimicrobial drugs. Keywords: ophthalmic antimicrobial agent, drug susceptibility, minimum inhibitory concentration, Clinical Laboratory and Standards Institut