109Use of EPR Spectroscopy to Measure Tissue Oxygen in an Ischemic Flap Model

Methods to reliably measure tissue oxygenation in situ are currently lacking. We have developed a vertically oriented, dorsal, bipedicle flap model that is easy to perform, reliably reproduces tissue ischemia, eliminates craniocaudal variation, and is amenable to studying therapeutic modalities. The effect of narrowing this flap on tissue oxygenation measured with Licox electrodes has previously been presented. In this study we utilize in situ EPR spectroscopy to demonstrate the oxygen gradient in the flap as a function of flap width and placement of a silicone sheet directly under the flap. The effect of wound healing over a 2 week period is demonstrated. Twenty four, 300 gm male Sprague‐Dawley rats underwent creation of the bipedicle flap according to the following groups: 2.5 cm flap with silicone, 2.0 cm flap without silicone, 2.0 cm flap with silicone. Each group of 6 animals was injected with EMS char at 2 cm intervals along the flap and one injection in the control, non‐ischemic tissue. A 4^th group underwent 2.0 cm flaps with silicone and use of lithium phthalocyanin as the paramagnetic material. Wound measurements and EPR spectroscopy were performed on days 3, 7, 10 and 14. On day 14, after EPR measurements, the animals were sacrificed and their wounds excised. One flap and one control wound were preserved for histologic analysis, the other flap and control wounds were prepared for lactate measurements. EPR spectroscopy demonstrated a gradient of oxygen that was lowest in the center of the flap and greatest at either end. Changes in the oxygen gradient correlated with narrowing and placement of the intervening silicone sheet. This new technology has never been utilized in an animal model of impaired wound healing. Comparison of recently developed paramagnetic materials for optimal tissue oxygen and free radical measurements will be presented.     

Acute Unilateral Anterior Ischemic Optic Neuropathy Secondary to Optic Nerve Head Drusen: Report of a Rare Coexistence

A 45-year-old white male noticed on awakening the painless loss of inferior vision in the left eye 2 days ago. He was otherwise well and his medical history was unremarkable. Visual acuity was 20/20 in OD and 20/32 in OS with a left inferior altitudinal defect and right blind spot enlargement demonstrable on visual field test. On fundus examination, both disc margins were blurred and the left disc was diffusely oedematous, with linear haemorrhages in the adjacent nerve fibre layer. Radiologic imaging and laboratory tests were unremarkable. Bilateral optic nerve head drusen (ONHD) was demonstrated by optical coherence tomography and fundus autofluorescence imaging. Unilateral acute non-arteritic anterior ischemic optic neuropathy (NAION) and concomitant bilateral ONHD were diagnosed. NAION may develop secondary to ONHD. Therefore, clinicians should be aware of this rare association and inform the patients about this risk. Patients with ONHD should be followed-up periodically in terms of possible ischemic complications.     

Meibomian gland alterations in polycystic ovary syndrome

PURPOSE: Polycystic ovary syndrome (PCOS) is an endocrinopathy characterized by chronic anovulation and hyperandrogenism where hyperinsulinemia can be seen. Hormonal changes can affect meibomian gland function. In this study, we evaluated tear function in PCOS. MATERIALS AND METHODS: Twenty-seven women having PCOS and 22 normal individuals aged between 18-42 years were enrolled in the study. Patients were asked about dry eye symptoms. Schirmer test, tear film breakup time, and rose Bengal staining were performed. Conjunctival brush cytology specimens were obtained and goblet cell count was done. RESULTS: Dry eye symptoms were more frequent in subjects with PCOS (p=0.025). Mean breakup time was shorter in women with PCOS (p=0.034). Schirmer test results, rose Bengal staining scores, and goblet cell count were not different between groups (p=0.48, p=0.18, p=0.82, respectively). CONCLUSION: Meibomian gland function and tear film lipid layer can be affected in cases with PCOS.     

The effects of caspofungin and voriconazole in experimental Candida endophthalmitis

PURPOSE: To evaluate the efficacy of newly developed antifungal agents caspofungin and voriconazole in Candida albicans endophthalmitis in rabbit eyes. METHODS: Thirty New Zealand white rabbits were divided into four treatment groups and one control group. One eye of each rabbit was infected by inoculation of 1 x 10(4) CFU/ml of C. albicans. Seventy-two hours after the inoculation, caspofungin 100 microg/0.1 ml in group 1 (n = 6), voriconazole 50 microg/0.1 ml in group 2 (n = 6), amphotericin B 10 microg/0.1 ml in group 3 (n = 6), itraconazole 10 microg/0.1 ml in group 4 (n = 6), and 0.1 ml NaCl 0.9% in control group (n = 6) were injected into the vitreous cavity. Clinical and histopathologic examination scores and microbiological analysis of vitreous aspirates were compared. RESULTS: There was statistically significant difference in the clinical scores, histopathologic scores, and mean CFU/ml between the treatment and control groups (p < 0.05). In caspofungin and voriconazole groups, histopathologic scores and mean CFU were lower than other treatment groups and control group. CONCLUSIONS: Intravitreal injection of caspofungin and voriconazole was effective against C. albicans endophthalmitis in this experimental rabbit model.     

Preclinical safety evaluation of intravitreal injection of full-length humanized vascular endothelial growth factor antibody in rabbit eyes

PURPOSE: To evaluate the preclinical safety of intravitreal bevacizumab, which is a full-length humanized monoclonal antibody against the vascular endothelial growth factor (VEGF), in rabbit eyes over a short-term period. METHODS: Twenty-four rabbits were divided into two groups, each with two subgroups. The first group (groups 1 and 2) received 1.25 mg (0.05 mL) intravitreal bevacizumab, and the second group (groups 3 and 4) received 3.00 mg (0.12 mL) intravitreal bevacizumab. The right eyes were designated as the study eyes, and the left eyes served as a control and received the same volume of saline intravitreally. Groups 1 and 3 were labeled as early groups and scheduled to be terminated at 14 days. Groups 2 and 4, labeled as late groups, were scheduled to be terminated at 28 days. Besides electroretinography (ERG) and visually evoked potentials (VEP), central corneal thickness, intraocular pressure, fundus photography, and anterior segment imaging were performed at baseline and scheduled time points. Enucleated eyes were preserved for light and electron microscopic investigation. RESULTS: No anterior segment inflammation was observed, except in one eye in group 1 which showed a uveitic reaction. No evidence of retinal toxicity was seen with intravitreal bevacizumab at doses of 1.25 and 3.00 mg, by either ERG or light microscopy. Electron microscopic assessment revealed mitochondrial damage in the inner segments of photoreceptors. Immunohistochemical staining with bax and caspase-3 and -9 showed intensive apoptotic protein expression in all study sections and minimal expression in the control eyes. CONCLUSIONS: Although electrophysiologic investigation and light microscopy showed normal retinal function and structure, mitochondrial disruption in the inner segments of photoreceptors was detected by electron microscopy, and apoptotic expression was detected after the injection of intravitreal bevacizumab.     

A case report of Fournier's gangrene: Imaging ultrasound and computed tomography (CT) scan

Necrotizing fasciitis and/or Fournier''s Gangrene is a rare, life-threatening soft tissue infection that, if not treated promptly, can immediately develop into systemic toxicity. It affects the genital, perineal, and perineal tissues, predominantly affecting men but can be seen in women. The diagnosis is often made clinically but radiologic examinations are helpful to determine the extent of the infection and can aid preoperative planning. Treatment consists of immediate and aggressive surgical debridement of necrotized tissue, broad-spectrum antibiotics, and early resuscitation. Here, we present a 56-year-old male patient with Fournier''s gangrene and describe the physical examination, bedside sonographic, and computed tomography findings. These findings can aid in the evaluation of patients with worrying symptoms so that antibiotics can be administered immediately and specialists can be consulted as needed.