Skin Infections and Outpatient Burn Management: Skin Infections in Patients With Diabetes.

Diabetes is associated with many complications, including foot ulcers. Individuals with diabetes have a 15% to 25% likelihood of developing a foot ulcer in their lifetime. The pathophysiologic mechanisms are multifactorial but the major etiologic factors are peripheral vascular disease and diabetic neuropathy. Foot examinations are recommended at least annually for patients with diabetes to assess the risk of foot ulcers and to detect, diagnose, and manage them. Management includes avoidance of walking, weight-bearing limitation, use of therapeutic footwear, use of dressings and debridement, and antibiotics. Due to immune dysfunction, diabetic neuropathy, and poor circulation, patients with diabetes are at increased risk of other types of infections. These include erythrasma, candidiasis, paronychia, onychomycosis, necrotizing fasciitis, Fournier gangrene, otitis externa, and nontuberculous mycobacterial skin infections. A high index of suspicion is required to diagnose these conditions. Patient evaluation may include a detailed physical examination, imaging, laboratory tests, and biopsies and cultures. Management may involve mechanical or surgical debridement, topical and oral antibiotics, and abscess drainage.

A role for astrocyte-derived amyloid ß peptides in the degeneration of neurons in an animal model of temporal lobe epilepsy.

Kainic acid, an analogue of the excitatory neurotransmitter glutamate, can trigger seizures and neurotoxicity in the hippocampus and other limbic structures in a manner that mirrors the neuropathology of human temporal lobe epilepsy (TLE). However, the underlying mechanisms associated with the neurotoxicity remain unclear. Since amyloid-ß (Aß) peptides, which are critical in the development of Alzheimer's disease, can mediate toxicity by activating glutamatergic NMDA receptors, it is likely that the enhanced glutamatergic transmission that renders hippocampal neurons vulnerable to kainic acid treatment may involve Aß peptides. Thus, we seek to establish what role Aß plays in kainic acid-induced toxicity using in vivo and in vitro paradigms. Our results show that systemic injection of kainic acid to adult rats triggers seizures, gliosis and loss of hippocampal neurons, along with increased levels/processing of amyloid precursor protein (APP), resulting in the enhanced production of Aß-related peptides. The changes in APP levels/processing were evident primarily in activated astrocytes, implying a role for astrocytic Aß in kainic acid-induced toxicity. Accordingly, we showed that treating rat primary cultured astrocytes with kainic acid can lead to increased Aß production/secretion without any compromise in cell viability. Additionally, we revealed that kainic acid reduces neuronal viability more in neuronal/astrocyte co-cultures than in pure neuronal culture, and this is attenuated by precluding Aß production. Collectively, these results indicate that increased production/secretion of Aß-related peptides from activated astrocytes can contribute to neurotoxicity in kainic acid-treated rats. Since kainic acid administration can lead to neuropathological changes resembling TLE, it is likely that APP/Aß peptides derived from astrocytes may have a role in TLE pathogenesis.

Endosomal-Lysosomal Cholesterol Sequestration by U18666A Differentially Regulates Amyloid Precursor Protein (APP) Metabolism in Normal and APP-Overexpressing Cells.

Amyloid ß (Aß) peptide, derived from amyloid precursor protein (APP), plays a critical role in the development of Alzheimer's disease. Current evidence indicates that altered levels or subcellular distribution of cholesterol can regulate Aß production and clearance, but it remains unclear how cholesterol sequestration within the endosomal-lysosomal (EL) system can influence APP metabolism. Thus, we evaluated the effects of U18666A, which triggers cholesterol redistribution within the EL system, on mouse N2a cells expressing different levels of APP in the presence or absence of extracellular cholesterol and lipids provided by fetal bovine serum (FBS). Our results reveal that U18666A and FBS differentially increase the levels of APP and its cleaved products, the α-, ß-, and η-C-terminal fragments, in N2a cells expressing normal levels of mouse APP (N2awt), higher levels of human wild-type APP (APPwt), or "Swedish" mutant APP (APPsw). The cellular levels of Aß1-40/Aß1-42 were markedly increased in U18666A-treated APPwt and APPsw cells. Our studies further demonstrate that APP and its cleaved products are partly accumulated in the lysosomes, possibly due to decreased clearance. Finally, we show that autophagy inhibition plays a role in mediating U18666A effects. Collectively, these results suggest that altered levels and distribution of cholesterol and lipids can differentially regulate APP metabolism depending on the nature of APP expression.

The Effects of Extracellular Serum Concentration on APP Processing in Npc1-Deficient APP-Overexpressing N2a Cells.

Amyloid precursor protein (APP) is cleaved by a set of proteases including α-/ß-/γ- and recently identified η-secretases, generating C-terminal fragments (CTFs) of varying lengths and amyloid ß (Aß) peptides, which are considered to play a pivotal role in Alzheimer's disease (AD) pathogenesis. Cellular cholesterol content/distribution can regulate the production/clearance of APP metabolites and hence modify AD pathology. To determine the functional relation between endosomal-lysosomal (EL) cholesterol sequestration and APP metabolism, we used our recently developed mouse N2a-ANPC cells that overexpress Swedish mutant human APP in the absence of cholesterol-trafficking Niemann-Pick type C1 (Npc1) protein. Here, we report that neither increased levels nor EL cholesterol sequestration altered APP holoprotein levels but caused the intracellular accumulation of APP α-/ß-/η-CTFs and Aß1-40/42 peptides. The levels of APP-cleaved products increased as a function of extracellular serum concentration in N2a-ANPC cells, which are more vulnerable to death than the control cells. Additionally, we show that pH of the lysosomal vesicles in N2a-ANPC cells shifted to a less acidic range with increasing serum concentrations, thus making them less efficient functionally. Interestingly, the addition of cholesterol to the culture media not only increased the levels of cellular cholesterol and APP-cleaved products but also rendered the cells more vulnerable to toxicity. Collectively, our results suggest that extracellular cholesterol concentration in serum under conditions of Npc1 deficiency can influence intracellular cholesterol content/distribution and lysosomal efficacy, triggering the accumulation of toxic APP-cleaved products, eventually leading to cell death.

Hidradenitis suppurativa, neutrophilic dermatoses and diverticular disease in a young African-American patient.

Hidradenitis suppurativa (HS) is a chronic skin disorder of the terminal follicular epithelium of apocrine sweat glands, manifesting as painful and exudative papules, pustules, cysts or nodules. This inflammatory condition often presents with other systemic and cutaneous disorders. We present the case of an African-American man with HS who was also diagnosed with neutrophilic dermatoses and diverticular disease. Neutrophilic dermatosis was identified based on histopathology findings. Our patient underwent multiple surgeries for flaring of his skin condition. Colchicine and doxycycline were started, but the patient was not able to tolerate them. Humira was planned for treatment of HS and neutrophilic dermatosis but could not be pursued because of the pericolic abscess. Colonoscopy and radiological investigation revealed multiple colonic diverticuli, for which he initially underwent percutaneous drainage followed by surgical removal of sigmoid mass and colocutaneous fistula. Culture from the specimen revealed abnormal growth of Actinomyces.

Treatment of selective antibody deficiency with IVIG resulting in decreased frequency of streptococcal infection and improvement of guttate psoriasis.

The association between guttate psoriasis and infection with group A Streptococcus (GAS) has been well established in the medical literature. However, responses to treatments aimed at GAS eradication such as systemic antibiotics or tonsillectomy are inconsistent. Further complicating treatment recommendations for a disease with a suspected microbial trigger, the standard therapy for severe psoriasis is with systemic immunosuppressant medications. This case report illustrates the role of GAS as a trigger for acute onset severe psoriasis in a child whose skin disease initially worsened with a trial of methotrexate. An immune evaluation confirmed a co-existing selective antibody deficiency. Subsequent treatment with intravenous immune globulin dramatically improved his underlying immune function and decreased GAS infections. This improvement in overall immune function and decrease in GAS infections cleared his skin disease. An interval change in formulation to subcutaneous immune globulin was not as effective.

Increased levels and activity of cathepsins B and D in kainate-induced toxicity.

Administration of kainic acid induces acute seizures that result in the loss of neurons, gliosis and reorganization of mossy fiber pathways in the hippocampus resembling those observed in human temporal lobe epilepsy. Although these structural changes have been well characterized, the mechanisms underlying the degeneration of neurons following administration of kainic acid remain unclear. Since the lysosomal enzymes, cathepsins B and D, are known to be involved in the loss of neurons and clearance of degenerative materials in a variety of experimental conditions, we evaluated their potential roles in kainic acid-treated rats. In parallel, we also measured the levels and expression of insulin-like growth factor-II/mannose 6-phosphate (IGF-II/M6P) receptors, which mediate the intracellular trafficking of these enzymes, in kainic acid-treated rats. Our results showed that systemic administration of kainic acid evoked severe loss of neurons along with hypertrophy of astrocytes and microglia in the hippocampus of the adult rat brain. The levels and activity of cathepsins B and D increased with time in the hippocampus of kainic acid-treated rats compared to the saline-injected control animals. The expression of both cathepsins B and D, as evident by immunolabeling studies, was also markedly increased in activated astrocytes and microglia of the kainic acid-treated rats. Additionally, cytosolic levels of the cathepsins were enhanced along with cytochrome c and to some extent Bax in the hippocampus in kainic acid-treated rats. These changes were accompanied by appearance of cleaved caspase-3-positive neurons in the hippocampus of kainic acid-treated animals. The levels of IGF-II/M6P receptors, on the other hand, were not significantly altered, but these receptors were found to be present in a subset of reactive astrocytes following administration of kainic acid. These results, taken together, suggest that enhanced levels/expression and activity of lysosomal enzymes may have a role in the loss of neurons and/or clearance of degenerative materials observed in kainic acid-treated rats.

Evaluation of the definitions of "high-risk" cutaneous squamous cell carcinoma using the american joint committee on cancer staging criteria and national comprehensive cancer network guidelines.

Recent guidelines from the American Joint Committee on Cancer (AJCC) and National Comprehensive Cancer Network (NCCN) have been proposed for the assessment of "high-risk" cutaneous squamous cell carcinomas (cSCCs). Though different in perspective, both guidelines share the common goals of trying to identify "high-risk" cSCCs and improving patient outcomes. Thus, in theory, both definitions should identify a similar proportion of "high-risk" tumors. We sought to evaluate the AJCC and NCCN definitions of "high-risk" cSCCs and to assess their concordance. Methods. A retrospective review of head and neck cSCCs seen by an academic dermatology department from July 2010 to November 2011 was performed. Results. By AJCC criteria, most tumors (n = 211,82.1%) were of Stage 1; 46 tumors (13.9%) were of Stage 2. Almost all were of Stage 2 due to size alone (≥2 cm); one tumor was "upstaged" due to "high-risk features." Using the NCCN taxonomy, 231 (87%) of tumors were "high-risk." Discussion. This analysis demonstrates discordance between AJCC and NCCN definitions of "high-risk" cSCC. Few cSCCs are of Stage 2 by AJCC criteria, while most are "high-risk" by the NCCN guidelines. While the current guidelines represent significant progress, further studies are needed to generate a unified definition of "high-risk" cSCC to optimize management.

Role of cholesterol in APP metabolism and its significance in Alzheimer's disease pathogenesis.

Alzheimer's disease (AD) is a complex multifactorial neurodegenerative disorder believed to be initiated by accumulation of amyloid ß (Aß)-related peptides derived from proteolytic processing of amyloid precursor protein (APP). Research over the past two decades provided a mechanistic link between cholesterol and AD pathogenesis. Genetic polymorphisms in genes regulating the pivotal points in cholesterol metabolism have been suggested to enhance the risk of developing AD. Altered neuronal membrane cholesterol level and/or subcellular distribution have been implicated in aberrant formation, aggregation, toxicity, and degradation of Aß-related peptides. However, the results are somewhat contradictory and we still do not have a complete understanding on how cholesterol can influence AD pathogenesis. In this review, we summarize our current understanding on the role of cholesterol in regulating the production/function of Aß-related peptides and also examine the therapeutic potential of regulating cholesterol homeostasis in the treatment of AD pathology.

Specific immunoglobulin isotypes correlate with disease activity, morphology, duration and HLA association in Pemphigus vulgaris.

The molecular basis of disease heterogeneity in autoimmune conditions such as Pemphigus vulgaris is poorly understood. Although desmoglein 3 (Dsg3) has been well established as a primary target of immunoglobulin (Ig) autoantibodies in PV, there remain several questions regarding the overall distribution of anti-Dsg3 Ig subtypes among patient subsets and considerable controversy regarding whether an isotype switch can be observed between phases of disease activity. To systematically address the outstanding questions related to Ig-isotype specificity in PV, we analyzed IgA, IgM, IgG1, 2, 3 and 4 anti-Dsg3 levels by ELISA in 202 serum samples obtained from 92 patients with distinct clinical profiles based on a set of defined variable (activity, morphology, age, duration) and constant (HLA-type, gender, age of onset) clinical parameters, and 47 serum samples from HLA-matched and -unmatched controls. Our findings provide support for earlier studies identifying IgG4 and IgG1 as the predominant antibodies in PV with significantly higher levels in active than remittent patients. We do not see evidence for an isotype switch between phases of disease activity and remission, and both IgG4 and IgG1 subtypes remain elevated in remittent patients relative to controls. We do, however, find IgG4 to be the sole subtype that further distinguishes PV patient subgroups based on different disease morphologies, disease duration, and HLA-types. These data provide further insight into the immune mechanisms responsible for phenotypic expression of disease, and contribute to the broader effort to establish comprehensive immunoprofiles underlying disease heterogeneity to facilitate increasingly specific and individualized therapeutic interventions.

Altered levels and distribution of amyloid precursor protein and its processing enzymes in Niemann-Pick type C1-deficient mouse brains.

Niemann-Pick type C (NPC) disease is an autosomal recessive neurodegenerative disorder characterized by intracellular accumulation of cholesterol and glycosphingolipids in many tissues including the brain. The disease is caused by mutations of either NPC1 or NPC2 gene and is accompanied by a severe loss of neurons in the cerebellum, but not in the hippocampus. NPC pathology exhibits some similarities with Alzheimer's disease, including increased levels of amyloid beta (Abeta)-related peptides in vulnerable brain regions, but very little is known about the expression of amyloid precursor protein (APP) or APP secretases in NPC disease. In this article, we evaluated age-related alterations in the level/distribution of APP and its processing enzymes, beta- and gamma-secretases, in the hippocampus and cerebellum of Npc1(-/-) mice, a well-established model of NPC pathology. Our results show that levels and expression of APP and beta-secretase are elevated in the cerebellum prior to changes in the hippocampus, whereas gamma-secretase components are enhanced in both brain regions at the same time in Npc1(-/-) mice. Interestingly, a subset of reactive astrocytes in Npc1(-/-) mouse brains expresses high levels of APP as well as beta- and gamma-secretase components. Additionally, the activity of beta-secretase is enhanced in both the hippocampus and cerebellum of Npc1(-/-) mice at all ages, while the level of C-terminal APP fragments is increased in the cerebellum of 10-week-old Npc1(-/-) mice. These results, taken together, suggest that increased level and processing of APP may be associated with the development of pathology and/or degenerative events observed in Npc1(-/-) mouse brains.

Evaluation of Pringle maneuver during liver resection in a rat model of surgical obstructive jaundice.

Temporary portal triad clamping (Pringle maneuver) during liver resection reduces intraoperative blood loss. A normal liver can safely tolerate normothermic ischemia for up to 60 min. However, its safety in patients with surgical obstructive jaundice (SOJ) is not known. Therefore, we investigated the effect of hepatic ischemia in an experimental rat model of SOJ created by ligating the bile duct. Four groups of rats were created: Group I (sham operation, 10 days later, liver resection); Group II (sham operation, 10 days later, liver resection with 5 min of hepatic ischemia); Group III (bile duct ligation, 10 days later, liver resection); and Group IV (bile duct ligation, 10 days later, liver resection with 5 min of hepatic ischemia). The ischemic injury was assessed by the survival of rats, liver tissue malondialdehyde and total glutathione (markers of free radical injury), serum alanine aminotransferase, aspartate aminotransferase, and liver histology. The results showed decreased survival (47.6% vs. 90% [p = .046]), increased liver tissue malondialdehyde (161 +/- 35 vs. 129 +/- 33 microg/gm liver tissue [p = .05]), and decreased liver tissue total glutathione (565 +/- 169 vs. 1075 +/- 276 nmol/gm liver tissue [p = .05]) in rats with SOJ subjected to hepatic ischemia when compared to nonjaundiced rats. The changes in serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase showed an increasing trend in the SOJ group but were not statistically significant. Ischemic changes in liver histology were seen more often in the SOJ group but were not statistically significant. These data suggest that temporary portal triad clamping in an experimental model of SOJ is detrimental to the outcome of liver resection.

Dose-dependent induction of endogenous antioxidants in rat heart by chronic administration of garlic.

The inhibitory property of garlic on free radical generation and lipid peroxidation has been reported in a number of in vitro studies. However, the in vivo effects of chronic garlic intake on the antioxidant milieu of heart has not been reported. Therefore, the present study was designed to investigate the effect of chronic garlic homogenate administration on myocardial endogenous antioxidants and lipid peroxidation at five different dosage levels (125, 250, 500, 1000 and 2000 mg/kg; B, C, D, E, F groups respectively). Garlic homogenate was administered orally to Wistar albino rats (150-200 gms) of either sex 6 days/week for 30 days. Myocardial TBARS (Thiobarbituric acid reactive substances) and antioxidants such as SOD (Superoxide Dismutase), catalase, GPx (glutathione peroxidase) and GSH (Reduced Glutathione) were estimated and histopathological changes were observed. Group F was excluded after 55% mortality occurred in 15 days. TBARS levels were significantly lower in groups B, C and D than that of control group (A). Catalase was increased significantly in groups C, D and E, whereas SOD increased significantly in groups B, C and D but decreased in group E. Significant increase in GSH in group E and significant reduction in GPx activity in group B were observed. Histopathological studies showed marked focal myocytolysis in group E. These results showed that chronic garlic intake dose dependently augmented endogenous antioxidants, which might have important direct cytoprotective effects on the heart, especially in the event of oxidant stress induced injury.