Original Magnification Research Articles

Primary cutaneous trichosporonosis caused by Trichosporon dermatis in an immunocompetent man

into the dermis with circumscribed lymphocyte aggregates in the epidermis (Pautrier microabscesses). C, Diffusely positive staining with CD25. D, Peripheral blood with a ‘‘flower cell’’—a lymphocyte with convoluted nuclei and prominent basophilic cytoplasm—characteristic in adult T-cell leukemia/lymphoma. (B and C, Hematoxylineeosin stain; original magnifications: A, 340; B, 3400; C, 3200; D, 3400.) J AM ACAD DERMATOL AUGUST 2011 434 Letters

Ameba-associated Keratitis, France

To the Editor: Amebic keratitis is an aggressive infection usually associated with soft contact lenses, and its poor outcome can lead to a corneal graft (1). Ameba can host ameba-resistant bacteria (2) and serve as a source for numerous organisms to exchange DNA, adapt to changing environments, and become pathogenic to the host (3). However, mixed keratitis caused by amebae in association with ameba-resistant pathogens is rarely seen. A 17-year-old woman who was myopic and had worn soft contact lenses for 3 years consulted our ophthalmology department for pain and redness of the left eye that had persisted for 2 weeks. No visual loss was reported, and a slit-lamp examination showed a millimetric epithelial defect associated with a round stromal infiltrate (Figure). No intraocular reaction was observed, and bacterial keratitis was diagnosed. Her condition improved after a 7-day topical fluoroquinolone treatment, and follow-up at 13 months showed only a slight superficial stromal scar. The patient reported that she had inappropriately worn monthly contact lenses for 3 months, cleaned and rinsed lenses with a commercial cleaning solution but diluted the solution with tap water, and washed her hands with tap water but did not dry them before handling the lenses. Figure Ameba-associated keratitis in a 17-year-old woman (contact lens wearer), France, showing a paracentral corneal scar (A) and recovery at 13-month follow-up (B). Original magnification ×10. Results of microbiologic analysis of a corneal scraping, which included molecular detection of ameba (18S rDNA), bacteria (16S rDNA), and herpesvirus (DNA polymerase), were negative. However, culture of contact lens storage case liquid in Page-modified Neff ameba saline enriched with heat-killed Enterobacter aerogenes (2) identified Pseudomonas fluorescens and Stenotrophomonas maltophilia, both of which were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (4); Mycobacterium chelonae, which was identified by rpoB gene sequencing; and Acanthamoeba polyphaga, which was identified by partial 18S rDNA sequencing. Culturing this ameba in sterile peptone–yeast extract–glucose broth showed that it hosted 4 organisms. The first organism was a new intracellular Deltaproteobacterium provisionally named Candidatus Babela massiliensis (100% 16S rDNA sequence similarity with a reference strain [GenBank accession no. {type:entrez-nucleotide,attrs:{text:GQ495224,term_id:258674431,term_text:GQ495224}}GQ495224], which was susceptible to 200 μg/mL rifampin and resistant to 20 μg/mL ciprofloxacin). The second organism was a new, unnamed, gram-negative, ciprofloxacin-susceptible (20 μg/mL) Alphaproteobacterium bacillus with 99% 16S rDNA sequence similarity (GenBank accession no. {type:entrez-nucleotide,attrs:{text:HM138368,term_id:299780300,term_text:HM138368}}HM138368) with Candidatus Odyssella sp. and Acanthamoeba endosymbiont KA/E9 (5). The third organism was a new giant virus related to an A. polyphaga mimivirus (6) strain Lentille. The fourth organism was a new virophage referred to as Sputnik 2 (7). Acanthamoeba spp. are ubiquitous in tap water (2,5), including that used by contact lens wearers to wash hands before manipulating the lens (8). Tap water hosts many organisms, including bacteria (2,5); large DNA viruses (9); and the recently described Sputnik virophage, a virus that infects ameba-resistant large DNA viruses (10). We found 5 bacterial species, a giant virus, and a virophage in the contact lens storage case liquid for this patient. Although Acanthamoeba spp. and M. chelonae are well-described agents of keratitis, other ameba-resistant organisms have not been associated with keratitis. However, 1 of the 2 new ameba-resistant bacteria isolated from the contact lens storage case liquid had a 16S rDNA sequence similar to that of the endosymbiont of an Acanthamoeba species isolated from the corneal sampling of a patient with keratitis in South Korea (5). These data indicate the ubiquity of these emerging organisms and raise questions about roles of the ameba host and the symbiont as causative agents of keratitis. We therefore estimate that any of the organisms reported or any combination of these agents could have been involved in the keratitis that developed in the patient. Because the minute quantity of corneal scraping material prevented molecular detection, the relative contribution of each organism could not be specified. This case illustrates that culturing ameba from ocular specimens and contact lens storage case liquid is mandatory for determining the diversity of pathogens potentially responsible for ameba-associated infections, such as keratitis, in patients who wear contact lenses. Ameba-resistant organisms have complex reciprocal interactions with the host, reminiscent of the mafia behavior. The patient’s practice of not drying her hands after cleansing them with tap water and diluting the contact lens cleansing liquid with tap water may have provided a route for contamination of the contact lens fluid with ameba-resistant, tap water–borne organisms. Patients should be informed of the risk for keratitis caused by water-borne, amebal-resistant pathogens. They should also be educated to avoid contact with tap water when manipulating contact lenses, to dry hands after washing them with water and soap, or to use antiseptics containing >70% alcohol for hand disinfection before contact lens manipulation.

Null-Type Anaplastic Lymphoma Kinase–Negative Anaplastic Large Cell Lymphoma Arising in a Silicone Breast Implant Capsule

Null-Type Anaplastic Lymphoma Kinase–Negative Anaplastic Large Cell Lymphoma Arising in a Silicone Breast Implant Capsule

Severe Leptospirosis Similar to Pandemic (H1N1) 2009, Florida and Missouri, USA

Severe Leptospirosis Similar to Pandemic (H1N1) 2009, Florida and Missouri, USA

Reduced apoptosis of CD8+ T-Lymphocytes in the airways of smokers with mild/moderate COPD

Chronic obstructive pulmonary disease (COPD) is characterised by chronic inflammation in airways and lung parenchyma. CD8+ T-lymphocytes, crucial effector and regulatory cells in inflammation, are increased in the central and peripheral airways in COPD. The aim of this study was to assess the role of apoptosis in the accumulation of CD8+ T-lymphocytes within the airway wall in COPD. We examined the submucosa of transverse sections of central and peripheral airways from post-operative tissues from non-smokers (n=16), smokers with normal lung function (n=16), smokers with mild/moderate COPD (n=16), and smokers with severe/very severe COPD (n=9). TUNEL and immunohistochemistry techniques were used to identify apoptosis and cell phenotype, respectively. The percentage of apoptotic CD8+ T-lymphocytes was significantly lower (p<0.0001) in smokers with mild/moderate COPD than in non-smokers, smokers with normal lung function, and smokers with severe/very severe COPD, and was positively related to values of FEV(1) and FEV(1)/FVC ratio, both in central and in peripheral airways. These data suggest that reduced apoptosis of CD8+ T-lymphocytes may be an important mechanism that contributes to the accumulation of these cells in the airway submucosa in smokers with mild/moderate COPD.

Cytomegalovirus-induced cutaneous vasculopathy and perianal ulceration

Cytomegalovirus-induced cutaneous vasculopathy and perianal ulceration

Transition of highly specific microRNA expression patterns in association with discrete maturation stages of human granulopoiesis

Transition of highly specific microRNA expression patterns in association with discrete maturation stages of human granulopoiesis

EBV‐associated hemophagocytic syndrome

General aspect of the marrow: macrophages with prominent phagocytosis of red cells, platelets, and erythroblasts. The marrow is overall hypocellular (MGG, original magnification ×400). High-power view of two characteristic hemophagocytic macrophages. (A) A macrophage with ingested red cells, platelets, erythroblasts, neutrophil, and assorted debris. (B) A macrophage which has engulfed a large number of erythroblasts (MGG, original magnification ×1,000). Hemophagocytic syndrome or hemophagocytic lymphohistiocytosis (HLH) is a rare syndrome characterized by fever, pancytopenia, organomegaly, multiorgan dysfunction, and hemophagocytosis by a large number of macrophages in bone marrow and other tissues [1]. Central to the pathophysiology is the impaired activity of NK and cytotoxic T lymphocytes resulting in uncontrolled immune activation, hypercytokinemia, and proliferation of macrophages. The diagnosis of HLH relies upon well-established criteria [2]. The syndrome has been described in familial conditions or as a secondary phenomenon to infections, malignancies, and collagen vascular diseases. HLH in the context of infection is best described in association with Epstein-Barr virus (EBV). EBV-associated HLH can occur either in primary infection or as a consequence of viral reactivation. EBV can also be the trigger in both familial and secondary cases. Although uncommon, hemophagocytic syndrome is a serious complication of EBV infection and can be fatal in many cases. Early recognition and prompt initiation of treatment are of great importance to reduce the high morbidity and mortality associated with this condition. The history and representative images from a case of EBV-associated hemophagocytic syndrome are described. The patient's consent has been obtained. A 25-year-old woman was admitted with fever, pancytopenia, and hepatic dysfunction. Five weeks previously, she was diagnosed with infectious mononucleosis on the basis of pharyngitis, fever, and positive EBV antibodies. In the weeks after diagnosis, she continued to complain of intermittent fevers and sweating. Past medical and family history were unremarkable. Physical examination revealed temperature 38°C, icteric sclera, and hepatosplenomegaly. Laboratory values included hemoglobin 8.1 g/dL, leucocytes 2,100 μL−1, neutrophils 720 μL−1, platelets 40,000 μL−1, bilirubin 7.4 mg/dL, ALT 135 U/L, LDH 1,080 U/L, triglycerides 459 mg/dL, and ferritin 6,070 ng/mL. Peripheral blood film morphology was unremarkable. The direct and indirect antiglobulin test and screening for cold autoagglutinins gave negative results. The reticulocyte automated count and absolute value were 1.11% and 31,900 μL−1, respectively, indicating impaired production of red cells. Bone marrow aspiration showed numerous macrophages with striking phagocytosis of blood cells and marrow precursors (Images 1 and 2). EBV serologies indicated primary infection, and the EBV-PCR result was 18,000 copies/mL. Genetic testing for familial HLH was negative. The patient was treated with methylprednisolone and intravenous immunoglobulins and eventually recovered completely.

Mucinous Cystic Neoplasm of the Pancreas

A healthy 31-year-old female presented with a 1-year history of microcytic anemia, which was associated ith abdominal pain and a 10-pound weight loss. On physical xamination, there was a palpable tender mass in the left upper uadrant of the abdomen. Previous investigations with an sophagogastroduodenoscopy and capsule endoscopy were esentially normal. However, an ultrasound of the abdomen reealed a complex multiseptated cystic mass measuring 16.5 11.5 cm within the pancreatic tail, as well as splenomegaly. ubsequent computed tomography scan of the abdomen conrmed the presence of the multiseptated lesion and it appeared o be closely associated with both the stomach and the body nd tail of the pancreas. Figure A shows a CT coronal image of the dumbbell-shaped multiseptated pancreatic mass, and an axial image is shown in Figure B. Further imaging with endoscopic ultrasound (EUS) revealed a multiseptated, predominantly cystic extrinsic mass, which appeared to be originating from the distal pancreas and also invading the stomach. Its ultasonographic features were consistent with a cystadenoma (Figure C) and scant mucin was visible on EUS-guided fineneedle aspiration. Serum tumor markers including carcinoembryonic antigen, carbohydrate antigen (CA) 19-9 and CA 125 were all within normal limits. During surgical exploration, a 19.5-cm encapsulated multilocular cyst was completely resected via distal pancreatectomy and splenectomy with en bloc subtotal distal gastrectomy, as the lesion was inseparable from the stomach. A gross image of the pancreatic mucinous cystic neoplasm encased in a smooth outer wall is seen in Figure D, and Figure E shows the multilobulated nature of this lesion in a cross-sectional image. This mass was confirmed to be originating from the pancreatic tail, with invasion of the adjacent gastric wall possibly because of prior cyst rupture leading to local inflammation and adhesion. Furthermore, it was occluding the splenic vein, and hence causing extensive venous congestion with resultant splenomegaly. On histology, the pancreatic mucinous cystic neoplasm was composed of glands lined by tall, mucinproducing cells, and ovarian-type stroma was also present without any evidence of invasive carcinoma cells (Figure F; HE original magnification 100). Additionally, the ovarian-type stromal cells

Follicular malignant melanoma: A case report of a metastatic variant and review of the literature

Follicular malignant melanoma: A case report of a metastatic variant and review of the literature

Psammomatous melanotic schwannoma with cystic changes from old hemorrhages in the cervical spinal canal: a case report

Psammomatous melanotic schwannoma with cystic changes from old hemorrhages in the cervical spinal canal: a case report

Investigation of Primary Cilia in the Pathogenesis of Biliary Atresia

Biliary atresia (BA) is an obliterative cholangiopathy presenting in the newborn period that leads to biliary cirrhosis and the need for liver transplantation in infancy unless treated early with a palliative Kasai portoenterostomy. BA is the most frequent indication for liver transplantation in children, but the pathogenesis remains unknown (1). Abnormalities of primary cilia are the cause of syndromes such as autosomal recessive polycystic kidney disease, in which renal cyst formation is associated with liver disease (2). The liver disease in ciliopathies is a ductal plate malformation leading either to congenital hepatic fibrosis or hepatic cyst development (3). In 10% to 20% of cases with BA (syndromic BA), there is an association with other specific developmental defects, including a laterality abnormality (situs inversus). Laterality is determined by primary cilia, and genes affecting laterality are involved in the organisation of cilial microtubules within the embryonal central node (4). In the present study we investigated children with BA who developed renal cysts to increase our understanding of the pathological process. We evaluated the effect of liver transplantation on cyst formation, assessed the role of primary cilia using fibrocystin as a cilial marker and looked for PKHD1 mutations in this group, and finally determined the function of their motile respiratory cilia.

The effect of post surface silanization and luting agents on the push-out bond strengths of adhesively inserted fiber reinforced posts

The effect of silane treatment on the push-out bond strengths of three different luting agents to fiber-reinforced composite (FRC) posts after thermocycling was evaluated. Sixty single-rooted human maxillary central incisors were sectioned below the cemento–enamel junction, and the roots were endodontically treated. RelyX Fiber Posts (size #2) were inserted using etch-and-rinse, self-etch, and self-adhesive luting agents (cementing agents). For half of the specimen in each group, the fiber posts were treated with a silane coupling agent. Bonded specimens were cut (2-mm-thick sections) and push-out tests were performed (crosshead speed, 0.5 mm/min). Failure modes were evaluated using a stereomicroscope at original magnification ×40. For each luting agent the use of silane did not result in any statistically significant difference at any level of the root compared to those of the control groups except for Variolink II and RelyX Unicem luting agents in apical root section ( p<0.05; one-way ANOVA). The post hoc analysis showed that regardless of the pre-treatment procedures, Variolink II achieved significantly higher bond strengths than Panavia F 2.0 and RelyX Unicem in all root sections ( p<0.05). The use of a silane coupling agent had no influence on bond strengths depending on the luting agent used, whereas the type of luting agent (etch-and-rinse, self-etch, and self-adhesive) appeared to be a significant influence on the push-out bond strength values independent of the pre-treatment used. Therefore, pre-treatment of fiber posts with a silane coupling agent does not seem to be mandatory, which saves time in the clinical situation.

Sperm-Associated Antigen 9 Is a Novel Biomarker for Colorectal Cancer and Is Involved in Tumor Growth and Tumorigenicity

Colorectal cancer (CRC) is the second most common tumor in developed countries. The present study was undertaken to determine the expression of the sperm-associated antigen 9 gene (SPAG9) as a possible biomarker in CRC, to investigate its correlation with humoral immune response and different stages and grades in CRC patients, and to explore its possible role in colon tumorigenesis in vitro and in an in vivo mouse model. SPAG9 expression was determined by RT-PCR, in situ RNA hybridization, and immunohistochemistry. Humoral response against SPAG9 was detected by enzyme-linked immunosorbent assay and Western blotting. SPAG9 gene silencing was performed using plasmid-based small interfering RNA to study various malignant properties of colon cancer cells in vitro and in vivo. The majority of CRC patients showed SPAG9 expression and generated humoral response. There was a close relationship between SPAG9 protein expression and humoral immune response in the majority of early-stage CRC patients, indicating that anti-SPAG9 antibodies could be a novel serum biomarker for early diagnosis. The down-regulation of SPAG9 (mediated by small interfering RNA) inhibited malignant properties in in vitro and significantly suppressed tumor growth in vivo. These findings collectively suggest that SPAG9 may have a role in tumor development and early spread and thus could serve as a novel target for early detection and for cancer immunotherapy.

Virtual electron microscopy in cell biology

Virtual microscopy of histological glass slides can emulate conventional light microscopy. Up till now, such a digital simulation does not exist for ultrathin electron microscopic slides. Because of the relative inaccessibility of electron microscopy, evaluation of subcellular structures by (bio)medical students is performed with the aid of photographic prints. In this article, the generation and evaluation of virtual electron microscopic slides is discussed. A T-lymphoblastic cell was used as an example. Electron microscopic pictures were taken at two magnifications (25,000 and 50,000), processed in an analogue or digital way and stitched to reconstruct the image of the total cell. This image is viewed with a webviewer equipped with pan and zoom functions. The possibility of distinguishing the trilaminar structure of cellular membranes was the requisite. Virtual images obtained at an original magnification of 25,000, scanned at a resolution of 800 ppi could compete with pictures developed directly from negatives obtained by electron microscopy. It is possible to navigate and zoom into details in a way emulating electron microscopy. Virtual electron microscopy is innovative and offers new perspectives to interpret cytological pictures and to teach cell biology in an interactive and unique way.

Coronary Angiitis and Cardiac Arrest in Antineutrophil Cytoplasmic-Antibody Associated Systemic Vasculitis

A 58-year-old man was admitted with a 6-week history of fever, lethargy, arthralgia, and dyspnea on exertion. He had no prior illness or cardiovascular risk factors, and with the exception of a pyrexia, his physical examination was unremarkable. Investigations were performed, including blood and urine cultures and a connective tissue screen. He was subsequently discharged with a view to an early outpatient review when he collapsed at home with cardiac arrest. The initial rhythm was ventricular fibrillation, which was successfully cardioverted. His postarrest electrocardiogram revealed transient right bundle-branch block and his plasma troponin I concentration was raised at 8.5 μg/L. His renal function was normal, but markers of …

Contrast Staining Outside the Sirolimus-Eluting Stent Leading to Coronary Aneurysm Formation

A 69-year-old man with prior myocardial infarction (hypertension; dyslipidemia; smoking; no diabetes; and no history of allergy, autoimmune disease, or vasculitis) underwent sirolimus-eluting stent (SES) implantation (3.0 mm in diameter; 33 mm in length) for chest pain on exertion with chronic total occlusion of the left anterior descending coronary artery (LAD) (Figure 1A through 1C and Video 1). Intravascular ultrasound examination after SES implantation demonstrated well-expanded stent struts without evidence of incomplete stent apposition (ISA) (Figure 1D through 1F). Figure 1. Baseline angiographic and intravascular ultrasound findings. A, Chronic total occlusion of the proximal LAD before percutaneous coronary intervention (arrow); B, collateral flow into the LAD from the right coronary artery (arrow); C, LAD after SES (3.0 mm in diameter; 33 mm in length) implantation (arrows); D through F, intravascular ultrasound images after SES implantation demonstrating well-expanded stent struts without evidence of incomplete stent apposition. Follow-up angiography at 8 months after initial SES implantation demonstrated multifocal contrast staining outside the stent contour with no evidence of angiographic restenosis (Figure 2A and Video 2). Subsequently, at 16 months after stenting, coronary angiography showed that the areas of contrast staining outside the stent contour increased in size (Figure 2B and Video 3). At 23 months after stenting, coronary artery aneurysm (CAA) formation was demonstrated in the midportion of the SES (Figure 2C and Video 4). The first 8-month …

Pyogenic Granuloma

A 10-year-old boy presented with a 2-month history of painless rectal bleeding. He had no fever, diarrhea, or weight loss. The patient had normal physical examination, normal laboratory testing including complete blood count, C-reactive protein, and stool cultures. Colonoscopy (Olympus PCF-Q180A1, Anamed KFT, Gyerekrak Foundation; Olympus, Tokyo, Japan) revealed a broad-based, multilobulated, inhomogeneous polypoid lesion 25 cm from the anus (Fig. 1). The polypoid lesion was removed piecemeal by oval electrosurgical snare (diameter 24 mm, Olympus) and standard cautery settings after its base was lifted with a 3-mL normal saline injection. Histology showed lobular capillary granuloma with small and dilated capillaries and a loose connective tissue stroma, which was consistent with pyogenic granuloma (Fig. 2). The patient developed abdominal pain the day following the procedure. Further investigation revealed free air on the abdominal x-ray, and he underwent surgical exploration. Colon perforation was diagnosed at the site of polypectomy and repaired. The patient recovered uneventfully and was discharged 5 days later.FIGURE 1: Broad-based, multilobulated, inhomogeneous polypoid lesion 25 cm from the anus.FIGURE 2: Polypoid area consists of hyperplastic colonic crypts and lobular capillary granuloma with small and dilated capillaries and a loose connective tissue stroma. Capillaries are surrounded by inflammatory cells. Hematoxylin and eosin stain, original magnification ×40.Pyogenic granuloma is a lobular capillary hemangioma that occurs mostly on the skin and on the mucosal surface of the oral cavity, but rarely in the gastrointestinal tract (1). There are only few reports of pyogenic granuloma in the colon of pediatric patients (2,3). The definitive diagnosis is made by histopathology, which shows granulation tissue, with endothelial-lined vascular spaces anastomosing with fibroblast proliferation. Postulated predisposing factors include trauma (solitary rectal ulcer), infection, microscopic arteriovenous anastomoses, and angiogenic growth factors. Endoscopic snare polypectomy or surgical resection is appropriate for definitive diagnosis and treatment. Recently, an obscure gastrointestinal bleeding due to pyogenic granuloma in the ileum was detected by capsule endoscopy and treated with double balloon enteroscopy (4).

Diabetic Retinopathy: Targeting Vasoregression

Diabetic retinopathy is a clinically well-defined, sight-threatening, chronic microvascular complication that eventually affects virtually all patients with diabetes. Diabetic retinopathy is characterized by gradually progressive alterations in the retinal microvasculature, leading to areas of retinal nonperfusion, increased vasopermeability, and in response to retinal nonperfusion, pathologic intraocular proliferation of retinal vessels (1–3). Most diabetes researchers and clinicians are aware of the major advances made in understanding the pathobiology of proliferative diabetic retinopathy. However mechanisms underlying the progressive alterations in retinal microvessels, which precede and stimulate neovascularization, are less well-known. In this review, current information about the pathogenesis of the primary lesion of diabetic retinopathy, retinal capillary vasoregression (see Fig. 1), is presented. FIG. 1. Phenotype of vasoregression in the diabetic retina. In both experimental diabetic rats and diabetic humans, capillary occlusions occur. Nondiabetic ( A ) and 6-month diabetic rat retina with acellular capillaries (arrows) ( B ). Nondiabetic ( C ) and diabetic ( D ) human retinal digest preparation. Periodic acid-Schiff staining (original magnification ×250). Diabetic retinopathy is often considered as a complication that contrasts with other vascular sequelae of this disease because it is associated with new vessel formation, while diabetic heart disease and diabetic nephropathy are characterized by impaired angiogenesis (4). Diabetic retinopathy is generally grouped with tumor angiogenesis and is presented as a paradigm of a neovascular disease (5). As outlined in this review, the natural history of diabetic retinopathy starts with vasoregression. Recent investigations have brought new insight regarding the primary vasoregressive process that stimulates angiogenesis, provoking new directions of thinking about possible prevention and intervention (1). Diabetic retinopathy starts with the loss of the two cellular components of retinal capillaries: the pericyte, a vessel support cell, and the endothelial cell. The exact sequence of loss in humans is not established because early human retinal samples are not available, but animal …

Edaravone reduces mitochondrial damage due to reperfusion injury following leg ischemia in rats

Free radicals have been implicated in reperfusion injury. It was shown that the free radical scavenger edaravone might suppress reperfusion injury in rat extremities. The present study aimed to elucidate how edaravone suppresses reperfusion injury, focusing on its effect on the mitochondrial structure and glycogen storage in the lower extremity muscles. Sixteen male Lewis rats (mean [± SD] weight 497±32 g) were divided into two groups and injected with either 3.0 mg/kg of edaravone (edaravone group, n=8 rats) or the same dose of saline (control group, n=8 rats) into the peritoneal cavity. The rat reperfusion injury models were created by clamping the bilateral common femoral arteries for 5 h, then declamping. The muscles were harvested more than 5 h after the start of reperfusion. The mitochondrial damage, defined as mitochondrial swelling, was examined using a transmission electron microscope at ×30,000 original magnification (n=3 for each rat). Glycogen storage, defined as a positive periodic acid-Schiff stain area, was examined using computerized densitometry (n=5 sections for each rat). The mitochondria in the control group demonstrated marked swelling (mean mitochondrial size = 0.169±0.059 μm(2)). However, the mitochondria in the edaravone group had significantly less swelling (mean mitochondrial size = 0.102±0.036 μm(2); P<0.01). The mean percentage of positive periodic acid-Schiff stain was also significantly higher in the edaravone group than in the control group (51.7±6.8% versus 7.3±2.1%; P<0.01). The results suggested that edaravone reduces mitochondrial damage due to reperfusion injury, resulting in a high level of glycogen storage.