The potential risk associated with foodborne pathogens in a watershed: Escherichia coli O157:H7 in dairy cattle.

We carried out an investigation to determine the occurrence of Escherichia coli O157:H7 in dairy herds in the Delaware County watershed and to identify the factors that play a role in the likelihood of presence of this organism among animals on these farms. The pathogen poses risk of environmental degradation and health to the inhabitants. A total of 2162 fecal samples were collected per rectum from a representative sample of cattle on 27 dairy farms. The samples were investigated for the presence of E. coli O157:H by initially enriching using a bacteriological media and detection of the pathogen using real-time polymerase chain reaction technique. Escherichia coli O157:H7 was detected in 74% of the herds in the target population and in 3.7% of samples collected. An additional 54 animals were identified that were infected with O157 non-H7 strains of E. coli among 15 farms. Several putative risk factors were associated with the detection of the pathogen on the enrolled farms included age, housing calves indoors, group housing for calves, housing calves in the calf barn, presence of dogs on the farm, and housing post-weaned calves in a cow barn or heifer barn versus a greenhouse. In conclusion, E. coli O157:H7 was present on the dairy farms of Delaware County and may pose a threat to the people that live and work there. The risk associated with the detection of this pathogen could be reduced by adjusting management factors that were identified in this study.

High-content analysis and Kinetic Image Cytometry identify toxicity and epigenetic effects of HIV antiretrovirals on human iPSC-neurons and primary neural precursor cells.

INTRODUCTION: Despite viral suppression due to combination antiretroviral therapy (cART), HIV-associated neurocognitive disorders (HAND) continue to affect half of people with HIV, suggesting that certain antiretrovirals (ARVs) may contribute to HAND. METHODS: We examined the effects of nucleoside/nucleotide reverse transcriptase inhibitors tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) and the integrase inhibitors dolutegravir (DTG) and elvitegravir (EVG) on viability, structure, and function of glutamatergic neurons (a subtype of CNS neuron involved in cognition) derived from human induced pluripotent stem cells (hiPSC-neurons), and primary human neural precursor cells (hNPCs), which are responsible for neurogenesis. RESULTS: Using automated digital microscopy and image analysis (high content analysis, HCA), we found that DTG, EVG, and TDF decreased hiPSC-neuron viability, neurites, and synapses after 7 days of treatment. Analysis of hiPSC-neuron calcium activity using Kinetic Image Cytometry (KIC) demonstrated that DTG and EVG also decreased the frequency and magnitude of intracellular calcium transients. Longer ARV exposures and simultaneous exposure to multiple ARVs increased the magnitude of these neurotoxic effects. Using the Microscopic Imaging of Epigenetic Landscapes (MIEL) assay, we found that TDF decreased hNPC viability and changed the distribution of histone modifications that regulate chromatin packing, suggesting that TDF may reduce neuroprogenitor pools important for CNS development and maintenance of cognition in adults. CONCLUSION: This study establishes human preclinical assays that can screen potential ARVs for CNS toxicity to develop safer cART regimens and HAND therapeutics.

Geography Shapes the Population Genomics of Salmonella enterica Dublin.

Salmonella enterica serotype Dublin (S. Dublin) is a bovine-adapted serotype that can cause serious systemic infections in humans. Despite the increasing prevalence of human infections and the negative impact on agricultural processes, little is known about the population structure of the serotype. To this end, we compiled a manually curated data set comprising of 880 S. Dublin genomes. Core genome phylogeny and ancestral state reconstruction revealed that region-specific clades dominate the global population structure of S. Dublin. Strains of S. Dublin in the UK are genomically distinct from US, Brazilian, and African strains. The geographical partitioning impacts the composition of the core genome as well as the ancillary genome. Antibiotic resistance genes are almost exclusively found in US genomes and are mediated by an IncA/C2 plasmid. Phage content and the S. Dublin virulence plasmid were strongly conserved in the serotype. Comparison of S. Dublin to a closely related serotype, S. enterica serotype Enteritidis, revealed that S. Dublin contains 82 serotype specific genes that are not found in S. Enteritidis. Said genes encode metabolic functions involved in the uptake and catabolism of carbohydrates and virulence genes associated with type VI secretion systems and fimbria assembly respectively.

Detection of Salmonella spp. in veterinary samples by combining selective enrichment and real-time PCR.

Rapid screening for enteric bacterial pathogens in clinical environments is essential for biosecurity. Salmonella found in veterinary hospitals, particularly Salmonella enterica serovar Dublin, can pose unique challenges for culture and testing because of its poor growth. Multiple Salmonella serovars including Dublin are emerging threats to public health given increasing prevalence and antimicrobial resistance. We adapted an automated food testing method to veterinary samples and evaluated the performance of the method in a variety of matrices including environmental samples ( n = 81), tissues ( n = 52), feces ( n = 148), and feed ( n = 29). A commercial kit was chosen as the basis for this approach in view of extensive performance characterizations published by multiple independent organizations. A workflow was established for efficiently and accurately testing veterinary matrices and environmental samples by use of real-time PCR after selective enrichment in Rappaport-Vassiliadis soya (RVS) medium. Using this method, the detection limit for S. Dublin improved by 100-fold over subculture on selective agars (eosin-methylene blue, brilliant green, and xylose-lysine-deoxycholate). Overall, the procedure was effective in detecting Salmonella spp. and provided next-day results.

Assay of Calcium Transients and Synapses in Rat Hippocampal Neurons by Kinetic Image Cytometry and High-Content Analysis: An In Vitro Model System for Postchemotherapy Cognitive Impairment.

Postchemotherapy cognitive impairment (PCCI) is commonly exhibited by cancer patients treated with a variety of chemotherapeutic agents, including the endocrine disruptor tamoxifen (TAM). The etiology of PCCI is poorly understood. Our goal was to develop high-throughput assay methods to test the effects of chemicals on neuronal function applicable to PCCI. Rat hippocampal neurons (RHNs) were plated in 96- or 384-well dishes and exposed to test compounds (forskolin [FSK], 17ß-estradiol [ES]), TAM or fulvestrant [FUL], aka ICI 182,780) for 6-14 days. Kinetic Image Cytometry™ (KIC™) methods were developed to quantify spontaneously occurring intracellular calcium transients representing the activity of the neurons, and high-content analysis (HCA) methods were developed to quantify the expression, colocalization, and puncta formed by synaptic proteins (postsynaptic density protein-95 [PSD-95] and presynaptic protein Synapsin-1 [Syn-1]). As quantified by KIC, FSK increased the occurrence and synchronization of the calcium transients indicating stimulatory effects on RHN activity, whereas TAM had inhibitory effects. As quantified by HCA, FSK also increased PSD-95 puncta and PSD-95:Syn-1 colocalization, whereas ES increased the puncta of both PSD-95 and Syn-1 with little effect on colocalization. The estrogen receptor antagonist FUL also increased PSD-95 puncta. In contrast, TAM reduced Syn-1 and PSD-95:Syn-1 colocalization, consistent with its inhibitory effects on the calcium transients. Thus TAM reduced activity and synapse formation by the RHNs, which may relate to the ability of this agent to cause PCCI. The results illustrate that KIC and HCA can be used to quantify neurotoxic and neuroprotective effects of chemicals in RHNs to investigate mechanisms and potential therapeutics for PCCI.

Infectious crystalline keratopathy in dogs and cats: clinical, in vivo confocal microscopic, histopathologic, and microbiologic features of eight cases.

OBJECTIVE: To describe clinical, in vivo confocal microscopic, histopathologic, and microbiologic features of canine and feline cases of infectious crystalline keratopathy (ICK). ANIMALS STUDIED: Six dogs and two cats with naturally acquired ICK. PROCEDURES: Medical records of dogs and cats with a clinical diagnosis of ICK were reviewed. Signalment, medical history, clinical findings, and diagnostic evaluations were retrieved, including corneal cytology, histopathology, in vivo confocal microscopy, and microbiology results. RESULTS: All animals presented with fine, needle-like, and branching white crystalline anterior stromal opacities emanating from corneal facets or corneal epithelial defects. Mild conjunctival hyperemia and anterior uveitis were frequently present. Concurrent ocular and systemic diseases were common, including keratoconjunctivitis sicca, corneal sequestrum, diabetes mellitus, hyperadrenocorticism, and malignant neoplasia. Bacteria, with minimal or absent leukocytes, were identified by cytology and histopathology. Histopathologically, the crystalline corneal opacities corresponded with dense accumulations of bacteria present in the interlamellar stromal spaces and forming cord-like projections within the stroma. In vivo confocal microscopy demonstrated deposits of reflective crystalline or amorphous structures within the stroma with a paucity of associated inflammatory changes. The most frequently cultured bacteria were alpha-hemolytic Streptococcus and Staphylococcus species. Resolution of clinical lesions was achieved in most cases with long-term medical or surgical therapy; however, the initiation of medical treatment was associated with an acute, dramatic onset of severe keratitis and anterior uveitis in some animals. CONCLUSIONS: Infectious crystalline keratopathy in dogs and cats shares many features with this condition in human patients. Prolonged medical therapy, or surgical intervention, is required for resolution.

MYC amplification in angiosarcomas arising in the setting of chronic lymphedema of morbid obesity.

BACKGROUND: Angiosarcoma is a malignancy of vascular endothelial cells which may arise secondarily as a complication of lymphedema, including chronic lymphedema of morbid obesity. Amplifications in MYC are frequently present in secondary angiosarcoma (arising in irradiated sites and chronic lymphedema) and less frequently in primary cutaneous angiosarcoma. OBJECTIVE: To describe the presence of MYC amplifications in two cases of cutaneous angiosarcoma secondary to chronic lymphedema of morbid obesity. METHODS: This study is a case series of two patients with cutaneous angiosarcoma. Clinical data was retrieved from the medical records. Histopathological analysis of the biopsy specimens was performed, including immunohistochemistry, along with fluorescence in situ hybridization. RESULTS: Angiosarcoma arose in the setting of massive chronic lymphedema complicating morbid obesity without other predisposing risk factors. Both cases exhibited epithelioid cell morphology and high-level MYC amplification. CONCLUSION: We report MYC amplification in two cases of angiosarcoma arising in massive chronic lymphedema of morbid obesity.

Specific prediction of clinical QT prolongation by kinetic image cytometry in human stem cell derived cardiomyocytes.

INTRODUCTION: A priority in the development and approval of new drugs is assessment of cardiovascular risk. Current methodologies for screening compounds (e.g. HERG testing) for proarrhythmic risk lead to many false positive and false negative results, resulting in the attrition of potentially therapeutic compounds in early development, and the advancement of other candidates that cause adverse effects. With improvements in the technologies of high content imaging and human stem cell differentiation, it is now possible to directly screen compounds for arrhythmogenic tendencies in human stem cell derived cardiomyocytes (hSC-CMs). METHODS: A training panel of 90 compounds consisting of roughly equal numbers of QT-prolonging and negative control (non-QT-prolonging) compounds, and a follow-up blinded study of 35 compounds including 16 from the 90 compound panel and 2 duplicates, were evaluated for prolongation of the calcium transient in hSC-CMs using kinetic image cytometry (KIC), a specialized form of high content analysis. RESULTS: The KIC-hSC-CM assay identified training compounds that prolong the calcium transient with 98% specificity, 97% precision, 80% sensitivity, and 89% accuracy in predicting clinical QT prolongation by these compounds. The follow-up study of 35 blinded compounds confirmed the reproducibility and strong diagnostic accuracy of the assay. DISCUSSION: The correlation of the KIC-hSC-CM results to clinical observations met or surpassed traditional preclinical assessment of cardiac risk utilizing animal models. Thus, the KIC-hSC-CM assay, which can be accomplished in high throughput and at relatively low cost, is an effective new model system for testing chemicals for cardiovascular risk.

The risk of carriage of Salmonella spp. and Listeria monocytogenes in food animals in dynamic populations.

Salmonella spp. and Listeria monocytogenes are foodborne pathogens of global importance. We assessed their risks and associated factors in a highly dynamic population of animals. Animal and environmental samples were collected from dairy cattle, sheep, camel and chickens at either the farms or the abattoirs. The pathogens were detected using a combination of bacterial enrichment culture and real-time polymerase chain reaction (PCR). Data on putative risk factors were collect and analysed for their significance of association with these pathogens. Salmonella spp. were detected at higher proportions in sheep faeces and sheep carcasses in comparison to cattle faeces (odds ratio = 2.4 and 2.2, respectively). This pathogen was less common in milk or carcasses samples from cattle or chickens. Sheep and camel carcass samples were highly contaminated with Salmonella spp. Faecal samples from cattle had the most diverse serovars of Salmonella enterica including S. Newport, S. Haifa, S. Kedougou, S. Kentucky, S. Mbandaka and S. Goettingen. Exotic serovars in sheep included S. Eastbourne, S. Chester and S. Kottnus. Serovars that were shed in camel faeces included S. Newport, S. Bovismorbificans and S. Infantis. In all sampled populations, detection of Salmonella spp. was more likely during warmer months than cold months. Listeria monocytogenes was not common in the targeted populations and was detected at a rate of 2.4%, mainly from sheep carcasses. The study highlights the role of food animals as reservoirs of pathogens across boundaries since all feed are imported in that population from different parts of the world.

Risk of Escherichia coli O157:H7, Non-O157 Shiga Toxin-Producing Escherichia coli, and Campylobacter spp. in Food Animals and Their Products in Qatar.

Escherichia coli O157:H7, non-O157 E. coli, and Campylobacter spp. are among the top-ranked pathogens that threaten the safety of food supply systems around the world. The associated risks and predisposing factors were investigated in a dynamic animal population using a repeat-cross-sectional study design. Animal and environmental samples were collected from dairy and camel farms, chicken processing plants, and abattoirs and analyzed for the presence of these pathogens using a combination of bacterial enrichment and real-time PCR tests without culture confirmation. Data on putative risk factors were also collected and analyzed. E. coli O157:H7 was detected by PCR at higher levels in sheep and camel feces than in cattle feces (odds ratios [OR], 6.8 and 21.1, respectively). Although the genes indicating E. coli O157:H7 were detected at a relatively higher rate (4.3%) in fecal samples from dairy cattle, they were less common in milk and udder swabs from the same animals (1 and 2%, respectively). Among the food adulterants, E. coli O103 was more common in cattle fecal samples, whereas O26 was more common in sheep feces and O45 in camel feces compared with cattle (OR, 2.6 and 3.1, respectively). The occurrence of E. coli in the targeted populations differed by the type of sample and season of the year. Campylobacter jejuni and Campylobacter coli were more common in sheep and camel feces than in cattle feces. Most of the survey and surveillance of E. coli focused on serogroup O157 as a potential foodborne hazard; however, based on the PCR results, non-O157 Shiga toxin-producing E. coli serotypes appeared to be more common, and efforts should be made to include them in food safety programs.

Airborne Priapism: A Case of Nonischemic Priapism After Military Static-Line Parachute Injury.

We report the case of a 21-year-old active duty U.S. Army soldier with painful and nonresolving priapism following blunt pelvic and lower extremity trauma from military static-line parachute injury during training. The patient's condition was initially managed with corporal aspiration and intracavernosal injections of phenylephrine that provided temporary relief but recurrence soon after. Referral to Urology at the site of the patient's injury yielded a diagnosis of penile hematoma. On subsequent evaluation by Urology on return to the patient's home duty station (over 96 hours after injury, with symptoms persisting), the corpora cavernosa were rigid, the corpus spongiosum was soft, and corporal blood gas drawn by the emergency department consistent with arterial blood. Penile duplex ultrasound revealed an isolated arterial-cavernosal fistula within the proximal left corporal body. The patient underwent percutaneous embolization of the fistula with successful resolution of his condition and return of normal erectile function. We discuss this unique case of high-flow priapism occurring after blunt trauma from military parachute injury and review suggested management in a stepwise fashion. The case is significant in that extensive literature review yields no previously described case of priapism following trauma from military parachute injury.

Phakomatous choristoma in a 10-week-old boy: a case report and review of the literature.

Phakomatous choristoma (PC) is a rare benign congenital lesion of lenticular anlage. It presents in young patients as a firm subcutaneous mass in the medial eyelid or orbit and may raise clinical concern for neoplasms such as rhabdomyosarcoma, but its histopathology is distinct, consisting of dense collagenous stroma and eosinophilic cuboidal epithelial cells forming nests, tubules, cords, or pseudoglands. We present a case of PC in a 10-week-old boy to illustrate the unique clinical, histopathologic, and immunophenotypic features of this condition and to reaffirm that familiarity with this rare entity aids accurate diagnosis.

Recombinant antigens rLipL21, rLoa22, rLipL32 and rLigACon4-8 for serological diagnosis of leptospirosis by enzyme-linked immunosorbent assays in dogs.

Animal leptospirosis is one of the most common zoonotic diseases in the United States and around the world. In a previous study, we applied four recombinant antigens, rLipL21, rLoa22, rLipL32 and rLigACon4-8 of Leptospira interrogans (L. interrogans) for the serological diagnosis of equine leptospirosis (Ye et al, Serodiagnosis of equine leptospirosis by ELISA using four recombinant protein markers, Clin. Vaccine. Immunol. 21:478-483). In this study, the same four recombinant antigens were evaluated for their potential to diagnose canine leptospirosis by ELISA. A total of 305 canine sera that were Leptospira microscopic agglutination test (MAT)-negative (n = 102) and MAT-positive (n = 203) to 5 serovars (Pomona, Grippotyphosa, Icterohaemorrhagiae, Canicola and Hardjo) were tested. When individual recombinant antigens were used, the sensitivity and specificity of ELISA were 97.5% and 84.3% for rLigACon4-8; 89.7% and 81.4% for rLoa22; 92.6% and 84.3% for rLipL32 and 99.5% and 84.3% for rLipL21, respectively compared to the MAT. The sensitivity and specificity of ELISA were, 92.6% and 91.2% for rLigACon4-8 and rLipL32, 97.5% and 84.3% for rLigACon4-8 and rLipL21, 89.7% and 87.3% for rLigACon4-8 and rLoa22, 89.7% and 87.3% to rLipL21 and rLoa22, 92.6% and 91.2% for rLipL21 and rLipL32 and 89.2% and 94.1% for rLoa22 and rLipL32 when one of the two antigens was test positive. The use of all four antigens in the ELISA assay was found to be sensitive and specific, easy to perform, and agreed with the results of the standard Leptospira Microscopic Agglutination test (MAT) for the diagnosis of canine leptospirosis.

Neuropathic orofacial pain: cannabinoids as a therapeutic avenue.

Neuropathic orofacial pain (NOP) exists in several forms including pathologies such as burning mouth syndrome (BMS), persistent idiopathic facial pain (PIFP), trigeminal neuralgia (TN) and postherpetic neuralgia (PHN). BMS and PIFP are classically diagnosed by excluding other facial pain syndromes. TN and PHN are most often diagnosed based on a typical history and presenting pain characteristics. The pathophysiology of some of these conditions is still unclear and hence treatment options tend to vary and include a wide variety of treatments including cognitive behaviour therapy, anti-depressants, anti-convulsants and opioids; however such treatments often have limited efficacy with a great amount of inter-patient variability and poorly tolerated side effects. Analgesia is one the principal therapeutic targets of the cannabinoid system and many studies have demonstrated the efficacy of cannabinoid compounds in the treatment of neuropathic pain. This review will investigate the potential use of cannabinoids in the treatment of symptoms associated with NOP.

Salmonella enterica serovar Oranienburg outbreak in a veterinary medical teaching hospital with evidence of nosocomial and on-farm transmission.

Nosocomial salmonellosis continues to pose an important threat to veterinary medical teaching hospitals. The objectives of this study were to describe an outbreak of salmonellosis caused by Salmonella enterica serovar Oranienburg within our hospital and to highlight its unique features, which can be used to help mitigate or prevent nosocomial outbreaks in the future. We retrospectively analyzed data from patients that were fecal culture-positive for Salmonella Oranienburg between January 1, 2006, and June 1, 2011, including historical, clinical, and pulsed-field gel electrophoresis (PFGE) data. Salmonella Oranienburg was identified in 20 horses, five alpacas, and three cows during this time frame, with dates of admission spanning the period from August, 2006, through January, 2008. We consider most of these patients to have become infected through either nosocomial or on-farm transmission, as evidenced by molecular subtyping results and supportive epidemiologic data. Interpretation of PFGE results in this outbreak was challenging because of the identification of several closely related Salmonella Oranienburg subtypes. Furthermore, a high percentage of cases were fecal culture-positive for Salmonella Oranienburg within 24 h of admission. These patients initially appeared to represent new introductions of Salmonella into the hospital, but closer inspection of their medical records revealed epidemiologic links to the hospital following the index case. Cessation of this outbreak was observed following efforts to further heighten biosecurity efforts, with no known cases or positive environmental samples after January, 2008. This study demonstrates that a Salmonella-positive culture result within 24 h of admission does not exclude the hospital as the source of infection, and it underscores the important role played by veterinary medical teaching hospitals as nodes of Salmonella infection that can promote transmission outside of the hospital setting.

Serodiagnosis of equine leptospirosis by enzyme-linked immunosorbent assay using four recombinant protein markers.

Leptospirosis, caused by Leptospira spp., is one of the most common zoonotic diseases in the world. We tested four recombinant proteins of Leptospira interrogans, namely, rLipL21, rLoa22, rLipL32, and rLigACon4-8, to evaluate their potential for use as antigens for the diagnosis of equine leptospirosis. We employed equine sera (n = 130) that were microscopic agglutination test (MAT) negative and sera (n = 176) that were MAT positive for the 5 serovars that most commonly cause equine leptospirosis. The sensitivity and specificity of ELISA compared to MAT were 82.39% and 86.15%, respectively, for LigACon4-8, 77.84% and 92.31%, respectively, for Loa22, 77.84% and 86.15%, respectively, for LipL32, and 84.66% and 83.85%, respectively, for LipL21. When one of the two antigens was test positive, the sensitivity and specificity of ELISA were 93.75% and 78.46%, respectively, for rLigACon4-8 and LipL32, 93.18% and 76.15%, respectively, for rLigACon4-8 and LipL21, 89.77% and 80.77%, respectively, for rLigACon4-8 and Loa22, 91.48% and 78.46%, respectively, for LipL21 and Loa22, 93.75% and 76.92%, respectively, for LipL21 and LipL32, and 90.34% and 80.77%, respectively, for Loa22 and LipL32. In conclusion, we have developed an indirect ELISA utilizing rLigACon4-8, rLoa22, rLipL32, and rLipL21 as diagnostic antigens for equine leptospirosis. The use of four antigens in the ELISA was found to be sensitive and specific, the assay was easy to perform, and the results concurred with the results of the standard Leptospira MAT.

Molecular detection of Salmonella species in bovine fecal samples.

A study was performed to assess the validity of the BAX automated polymerase chain reaction system (DuPont Nutrition & Health, Wilmington, Delaware) to detect the shedding of Salmonella species in bovine fecal samples. A total of 133 bovine fecal samples that were submitted to the Cornell University Animal Health Diagnostic Laboratory for Salmonella culture were also tested in the BAX system with a modified version of the manufacturer's enrichment protocol. Using culture as the gold standard test, the BAX system was found to have a sensitivity of 85.7% and a specificity of 90.5%. There was excellent agreement (κ = 0.71, standard error = 0.072) and no significant differences between the 2 methods (McNemar χ(2) = 0.180).

Automated methods for the analysis of skeletal muscle fiber size and metabolic type.

It is of interest to quantify the size, shape, and metabolic subtype of skeletal muscle fibers in many areas of biomedical research. To do so, skeletal muscle samples are sectioned transversely to the length of the muscle and labeled for extracellular or membrane proteins to delineate the fiber boundaries and additionally for biomarkers related to function or metabolism. The samples are digitally photographed and the fibers "outlined" for quantification of fiber cross-sectional area (CSA) using pointing devices interfaced to a computer, which is tedious, prone to error, and can be nonobjective. Here, we review methods for characterizing skeletal muscle fibers and describe new automated techniques, which rapidly quantify CSA and biomarkers. We discuss the applications of these methods to the characterization of mitochondrial dysfunctions, which underlie a variety of human afflictions, and we present a novel approach, utilizing images from the online Human Protein Atlas to predict relationships between fiber-specific protein expression, function, and metabolism.

Toxic epidermal necrolysis: Part I. Introduction, history, classification, clinical features, systemic manifestations, etiology, and immunopathogenesis.

Toxic epidermal necrolysis is a life-threatening, typically drug-induced mucocutaneous disease. It is clinically characterized as a widespread sloughing of the skin and mucosa, including both external and internal surfaces. Histologically, the denuded areas show full thickness epidermal necrosis. The pathogenic mechanism involves antigenic moiety/metabolite, peptide-induced T cell activation, leading to keratinocyte apoptosis through soluble Fas ligand, perforin/granzyme B, tumor necrosis factor-alfa, and nitric oxide. Recent studies have implicated granulysin in toxic epidermal necrolysis apoptosis and have suggested that it may be the pivotal mediator of keratinocyte death.