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Reactivation
Kinds of Reactivation Selected AbstractsTHE EVOLUTION OF A MODEL TRAP IN THE CENTRAL APENNINES, ITALY: FRACTURE PATTERNS, FAULT REACTIVATION AND DEVELOPMENT OF CATACLASTIC ROCKS IN CARBONATES AT THE NARNI ANTICLINEJOURNAL OF PETROLEUM GEOLOGY, Issue 2 2001F. Storti Recent hydrocarbon discoveries in the Southern Apennines of Italy have focussed attention on the importance of studying fracturing and cataclasis in carbonate rocks because of their fundamental impact on reservoir permeability and connectivity. The Narni Anticline in the central Apennines consists of a stack of easterly-verging carbonate thrust sheets compartmentalized by extensional and strike-slip fault zones. The structure provides afield analogue for studying the evolution of superimposed fold- and fault-related fractures in carbonate reservoir rocks. The fracture pattern at the Narni Anticline developed as a result of three mechanisms: (a) layer-parallel shortening predating folding and faulting; (b) thrust-related folding and further thrust breakthrough; and (c) extensional and strike-slip faulting. Along-strike (longitudinal) fractures developed during progressive rollover fault-propagation folding, and their intensity depends on the precise structural position within the fold: fracture intensity is high in the forelimb and low in the crest. The 3-D architecture of the mechanical anisotropy associated with thrusting, folding, and related fracturing constrained the location and geometry of subsequent extensional and strike-slip faulting. The superimposition in damage zones of a fault-related cleavage on the pre-existing fracture pattern, which is associated with layer-parallel shortening and thrust-related folding, resulted in rock fragmentation and comminution, and the development of cataclastic bands. The evolution of fracturing in the Narni Anticline, its role in constraining thrust breakthrough trajectories and the location of extensional and strike-slip faults, and the final development of low-permeability cataclastic bands, will be relevant to studies of known oilfields in the Southern Apennines, as well as for future exploration. [source] UV-A/BLUE LIGHT,INDUCED REACTIVATION OF SPORE GERMINATION IN UV-B IRRADIATED ULVA PERTUSA (CHLOROPHYTA),JOURNAL OF PHYCOLOGY, Issue 2 2004Taejun Han Recent reduction in the ozone shield due to manufactured chlorofluorocarbons raised considerable interest in the ecological and physiological consequences of UV-B radiation (,=280,315 nm) in macroalgae. However, early life stages of macroalgae have received little attention in regard to their UV-B sensitivity and UV-B defensive mechanisms. Germination of UV-B irradiated spores of the intertidal green alga Ulva pertusa Kjellman was significantly lower than in unexposed controls, and the degree of reduction correlated with the UV doses. After exposure to moderate levels of UV-B irradiation, subsequent exposure to visible light caused differential germination in an irradiance- and wavelength-dependent manner. Significantly higher germination was found at higher photon irradiances and in blue light compared with white and red light. The action spectrum for photoreactivation of germination in UV-B irradiated U. pertusa spores shows a major peak at 435 nm with a smaller but significant peak at 385 nm. When exposed to December sunlight, the germination percentage of U. pertusa spores exposed to 1 h of solar radiation reached 100% regardless of the irradiation treatment conditions. After a 2-h exposure to sunlight, however, there was complete inhibition of germination in PAR+UV-A+UV-B in contrast to 100% germination in PAR or PAR+UV-A. In addition to mat-forming characteristics that would act as a selective UV-B filter for settled spores under the parental canopy, light-driven repair of germination after UV-B exposure could explain successful continuation of U. pertusa spore germination in intertidal settings possibly affected by intense solar UV-B radiation. [source] The role of BDNF and its receptors in depression and antidepressant drug action: Reactivation of developmental plasticityDEVELOPMENTAL NEUROBIOLOGY, Issue 5 2010Eero Castrén Abstract Recent evidence suggests that neuronal plasticity plays an important role in the recovery from depression. Antidepressant drugs and electroconvulsive shock treatment increase the expression of several molecules, which are associated with neuronal plasticity, in particular the neurotrophin BDNF and its receptor TrkB. Furthermore, these treatments increase neurogenesis and synaptic numbers in several brain areas. Conversely, depression, at least in its severe form, is associated with reduced volumes of the hippocampus and prefrontal cortex and in at least some cases these neurodegenerative signs can be attenuated by successful treatment. Such observations suggest a central role for neuronal plasticity in depression and the antidepressant effect, and also implicate BDNF signaling as a mediator of this plasticity. The antidepressant fluoxetine can reactivate developmental-like neuronal plasticity in the adult visual cortex, which, under appropriate environmental guidance, leads to the rewiring of a developmentally dysfunctional neural network. These observations suggest that the simple form of the neurotrophic hypothesis of depression, namely, that deficient levels of neurotrophic support underlies mood disorders and increases in these neurotrophic factors to normal levels brings about mood recovery, may not sufficiently explain the complex process of recovery from depression. This review discusses recent data on the role of BDNF and its receptors in depression and the antidepressant response and suggests a model whereby the effects of antidepressant treatments could be explained by a reactivation of activity-dependent and BDNF-mediated cortical plasticity, which in turn leads to the adjustment of neuronal networks to better adapt to environmental challenges. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 2010 [source] Liver dysfunction after chemotherapy in lymphoma patients infected with hepatitis CEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 5 2008Omer Dizdar Abstract Reactivation of hepatitis B virus (HBV) infection in asymptomatic hepatitis B surface antigen carriers undergoing chemotherapy or immunosuppressive therapy is a well-documented complication. However, data on the consequence of chemotherapy on the course of hepatitis C virus (HCV) infection in HCV(+) patients have been controversial. Here, we review the current knowledge about the complications related to HCV in lymphoma patients receiving chemotherapy/immunosuppressive therapy. Although less frequent than HBV, these complications occur in a subset of patients with mortality rates up to 45%. Therefore, baseline screening for HBV and HCV before initiation of chemotherapy is crucial. High-risk patients having chronic active hepatitis, high baseline HCV viral load, HBV co-infection and receiving cytotoxic drugs, corticosteroids and rituximab (particularly if combined) should be closely monitored for serum transaminase, bilirubin and HCV RNA levels. [source] Identification of candidate tumor suppressor genes inactivated by promoter methylation in melanomaGENES, CHROMOSOMES AND CANCER, Issue 1 2009Vanessa F. Bonazzi Tumor suppressor genes (TSGs) are sometimes inactivated by transcriptional silencing through promoter hypermethylation. To identify novel methylated TSGs in melanoma, we carried out global mRNA expression profiling on a panel of 12 melanoma cell lines treated with a combination of 5-Aza-2-deoxycytidine (5AzadC) and an inhibitor of histone deacetylase, Trichostatin A. Reactivation of gene expression after drug treatment was assessed using Illumina whole-genome microarrays. After qRT-PCR confirmation, we followed up 8 genes (AKAP12, ARHGEF16, ARHGAP27, ENC1, PPP1R3C, PPP1R14C, RARRES1, and TP53INP1) by quantitative DNA methylation analysis using mass spectrometry of base-specific cleaved amplification products in panels of melanoma cell lines and fresh tumors. PPP1R3C, ENC1, RARRES1, and TP53INP1, showed reduced mRNA expression in 35,59% of the melanoma cell lines compared to melanocytes and which was correlated with a high proportion of promoter methylation (>40,60%). The same genes also showed extensive promoter methylation in 6,25% of the tumor samples, thus confirming them as novel candidate TSGs in melanoma. © 2008 Wiley-Liss, Inc. [source] GEOMORPHOLOGICAL AND DENDROCHRONOLOGICAL ANALYSES OF A COMPLEX LANDSLIDE IN THE SOUTHERN APENNINESGEOGRAFISKA ANNALER SERIES A: PHYSICAL GEOGRAPHY, Issue 3 2008DOMENICO GUIDA ABSTRACT. Complex landslides, capable of reactivation, are typical slope movements in high relief areas. Due to their distribution, size and kinematics, these landforms represent a major hazard, posing a high risk to populations, settlements and infrastructures. This paper integrates geomorphological analyses, instrumental measurements and dendrochronological approaches in assessing a large, reactivated landslide system on the southern piedmont of Monte Sirino (southern Italy). The landslide system is associated with weak geological structures, earthquake activity, and rapid recent incision of the mid-Pleistocene Noce lake deposits. Potential reactivation triggers include a higher regional annual rainfall, one of the highest in southern Italy, and more frequent heavy snowfalls in recent decades. Reactivation of the Sirino landslide system has important implications for the motorway connecting Salerno and Reggio Calabria, which crosses it. The results of our study show that the slide is reactivated with an almost decadal frequency and that major reactivations are correlated to prolonged snowfall, which occurs with increasing frequency in the southern Apennines. The last observation suggests the need for similar studies on the behaviour of other landslide systems in the southern Apennines, performing integrated approaches such as geotechnical and dendrogeomorphological analysis. [source] From learning to forgetting: Behavioral, circuitry, and molecular properties define the different functional states of the recognition memory traceHIPPOCAMPUS, Issue 5 2010Rocío Romero-Granados Abstract Neuropsychological analyses of amnesic patients, as well as lesion experiments, indicate that the temporal lobe is essential for the encoding, storage, and expression of object recognition memory (ORM). However, temporal lobe structures directly involved in the consolidation and reconsolidation of these memories are not yet well-defined. We report here that systemic administration of a protein synthesis inhibitor before or up to 4 h after training or reactivation sessions impairs consolidation and reconsolidation of ORM, without affecting short-term memory. We have also observed that ORM reconsolidation is sensitive to protein synthesis inhibition, independently of the ORM trace age. Using bdnf and egr-1 gene expression analysis, we defined temporal lobe areas related to consolidation and reconsolidation of ORM. Training and reactivation 21 days after ORM acquisition sessions provoked changes in bdnf mRNA in somatosensory, perirhinal, and hippocampal cortices. Reactivation 2 days after the training session elicited changes in bdnf and egr-1 mRNA in entorhinal and prefrontal cortices, while reactivation 9 days post-training provoked an increase in egr-1 transcription in somatosensory and entorhinal cortices. The differences in activated circuits and in the capacity to recall the memory trace after 9 or 21 days post-training suggest that memory trace suffers functional changes in this period of time. All these results indicate that the functional state of the recognition memory trace, from acquisition to forgetting, can be specifically defined by behavioral, circuitry, and molecular properties. © 2009 Wiley-Liss, Inc. [source] Reactivation with a simple exposure to the experimental environment is sufficient to induce reconsolidation requiring protein synthesis in the hippocampal CA3 region in miceHIPPOCAMPUS, Issue 3 2007Julien Artinian Abstract Our understanding of the memory reconsolidation process is at an earlier stage than that of consolidation. For example, it is unclear if, as for memory consolidation, reconsolidation of a memory trace necessitates protein synthesis. In fact, conflicting results appear in the literature and this discrepancy may be due to differences in the experimental reactivation procedure. Here, we addressed the question of whether protein synthesis in the CA3 hippocampal region is crucial in memory consolidation and reconsolidation of allocentric knowledge after reactivation in different experimental conditions in the Morris water maze. We showed (1) that an injection of the protein synthesis inhibitor anisomycin in the CA3 region during consolidation or after a single reactivation trial disrupted performance and (2) that protein synthesis is required even after a simple contextual reactivation without any learning trial and independently of the presence of the reinforcement. This work demonstrates that a simple exposure to the spatial environment is sufficient to reactivate the memory trace, to make it labile, and that reconsolidation of this trace requires de novo protein synthesis. © 2007 Wiley-Liss, Inc. [source] Apparent Reactivation of a Fibrohistiocytic Proliferation with Features of Dermatofibroma and Dermatomyofibroma Following Systemic ImmunosuppressionJOURNAL OF CUTANEOUS PATHOLOGY, Issue 1 2005W.A. High A 41 year-old man presented with an atrophic, hyperpigmented plaque on the right lower abdomen present since"birth". He denied any prior activity at the site, and had been told it was a "scar" from a prenatal insult. Six months earlier, he developed idiopathic focal sclerosing glomerulonephritis and was placed on 70 mg prednisone per day. He had not demonstrated evidence of lupus eythematosus. Shortly after beginning this regimen, erythematous and tender papules developed around the quiescent plaque. He had tapered his prednisone dose to 60 mg per day, but additional papules continued to erupt. An ellipse biopsy was performed which included a portion of the atrophic plaque and several surrounding papules. Histological examination revealed a proliferation of fibrohistiocytes between and amongst collagen bundles. In some areas, fibrohistiocytes entrapped collagen in a fashion reminiscent of a dermatofibroma. In other areas, particularly that of the atrophic plaque, the fibrohistiocytes were less numerous and more delicate in appearance. Scattered rudimentary fascicles were demonstrated. Adnexal structures were preserved. Immunohistochemical staining revealed the fibrohistiocytes to be positive for factor XIIIa and actin, but negative for desmin, CD34, S-100, procollagen I, and CD68. This lesion demonstrated unique clinical/histiological aspects not well characterized in the literature. [source] Reactivation of spent Pd/AC catalyst by supercritical CO2 fluid extractionAICHE JOURNAL, Issue 9 2009Xiaoxin Zhang Abstract In this article, we reported a nondestructive and environmentally friendly method for the reactivation of a spent Pd/AC catalyst for the hydrogenation of benzoic acid by using supercritical CO2 (scCO2) fluid extraction. The effects of reactivation conditions, such as extraction temperature, pressure, CO2 flow rate, and time, on the activity of the reactivated Pd/AC catalyst, were presented. The catalyst was characterized by N2 physisorption, laser particle size analysis, and transmission electron spectroscopy, and the liquid extract was analyzed by GC-MS. It is found that scCO2 fluid extraction was very efficient in eliminating organic substances blocking the pores of the catalyst, while did not affect noticeably the granule size of the catalyst and the particle size of Pd. The reactivated Pd/AC catalyst regained more than 70% of the activity of the fresh 5.0 wt % Pd/AC catalyst, and has been successfully used in an industrial unit for the hydrogenation of benzoic acid. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Identification of a unique BK virus variant in the CNS of a patient with AIDS,JOURNAL OF MEDICAL VIROLOGY, Issue 1 2003Gunn Eli Kimo Jørgensen Abstract Human polyomavirus BK (BKV; GenBank or EMBL or DDBJ accession no. NC001538) is often reactivated in immunosuppressed patients. Reactivation has been associated primarily with excretion of the virus in the urine, and there have been few reports of renal and/or neurological disease caused by BKV in patients with acquired immunodeficiency syndrome (AIDS). Polymerase chain reaction, Southern blotting, and sequencing were used to detect and identify the noncoding control region (NCCR) of BKV in different tissues in an AIDS patient with meningoencephalitis, retinitis, and nephritis. An undescribed reorganized NCCR variant of the virus, completely different from the variants detected in peripheral blood leukocytes (PBLs) and urine, was identified in the cerebrospinal fluid (CSF) and CNS tissues. These results suggest that rearrangements in the NCCR of the virus have resulted in a BKV variant, which is better adapted to the host cell machinery of the cells in CNS tissue. The rearranged variant (BKV CNS) might have been involved in the initiation and/or development of the pathological lesions observed in the CNS-related tissues of this patient. J. Med. Virol. 70: 14,19, 2003. © 2003 Wiley-Liss, Inc. [source] Prevalence of oral herpes simplex virus reactivation in cancer patients: a comparison of different techniques of viral detectionJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 2 2009Milanko Djuric Background:, Oral reactivation of latent Herpes simplex virus (HSV) infection may easily occur in cancer patients. Virus reactivation can cause oral mucosa damage, worsen already existing lesions caused by stomatotoxic effect of cancer therapy and, whether symptomatic or asymptomatic, ample spreading and promote viral transmission. Methods:, Polymerase chain reaction (PCR), cell-culture and direct immunofluorescence have been used to determine the frequency of oral HSV reactivation in 60 patients undergoing chemotherapy for different malignancies. Results:, By means of PCR, the presence of viral DNA was detected in 71.7% of patients prior to chemotherapy and in 85.0% after chemotherapy. 33.3% of patients before and 40.0% after chemotherapy were viral-culture positive, while 3.3% of patients before and 11.7% after chemotherapy were positive as shown by direct immunofluorescence. No significant difference in HSV-1 reactivation was found before and after chemotherapy. In addition, no significant difference was found when comparing HSV-1 reactivation in patients with and without mucositis. HSV-2 was not detected in any of the patients. Conclusions:, Reactivation of latent HSV is exceptionally frequent in cancer patients. The results of this study suggest that virus reactivation occurs independently of cancer chemotherapy. The potential role of HSV reactivation in oral mucosa damage remains unclear. [source] Herpesviruses in human periodontal diseaseJOURNAL OF PERIODONTAL RESEARCH, Issue 1 2000Adolfo Contreras Recent studies have identified various herpesviruses in human periodontal disease. Epstein,Barr virus type 1 (EBV-1) infects periodontal B-lymphocytes and human cytomegalovirus (HCMV) infects periodontal monocytes/macrophages and T-lymphocytes. EBV-1, HCMV and other herpesviruses are present more frequently in periodontitis lesions and acute necrotizing ulcerative gingivitis-lesions than in gingivitis or periodontally healthy sites. Reactivation of HCMV in periodontitis lesions tends to be associated with progressing periodontal disease. Herpesvirus-associated periodontitis lesions harbor elevated levels of periodontopathic bacteria, including Acrinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Bacteriodes forsythus, Prevotella intermedia, Prevotella nigrescens and Treponema denticola. It may be that active periodontal herpesvirus infection impairs periodontal defenses, thereby permitting subgingival overgrowth of periodontopathic bacteria. Alteration between latent and active herpesvirus infection in the periodontium might lead to transient local immunosuppression and explain in part the episodic progressive nature of human periodontitis. Tissue tropism of herpesvirus infections might help explain the localized pattern of tissue destruction in periodontitis. Absence of herpesvirus infection or viral reactivation might explain why some individuals carry periodontopathic bacteria while still maintaining periodontal health. Further studies are warranted to delineate whether the proposed herpesvirus-periodontopathic bacteria model might account for some of the pathogenic features of human periodontal disease. [source] Screening for hepatitis B in chemotherapy patients: survey of current oncology practicesALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 2 2010T. T. TRAN Summary Background, Hepatitis B virus (HBV) reactivation occurs in up to 78% of patients receiving cytotoxic chemotherapy for nonhepatic malignancies. Reactivation can lead to hepatic dysfunction, jaundice and fulminant hepatic failure. Current recommendations include screening patients at risk for HBV prior to immunosuppressive therapy and initiating antiviral prophylaxis in patients with chronic HBV. Aim, To investigate current practice among oncologists regarding HBV screening and antiviral prophylaxis in candidates for chemotherapy. Methods, A survey was sent to American Medical Association registered oncologists assessing demographics and HBV screening practices. Statistical analysis was performed using Fisher's exact test. Results, In all, 265 responses were received. Office-based physicians were less likely to screen for HBV prior to chemotherapy (P < 0.001). Years in practice varied: 51% with <5 years, 29% with 5,15 years and 18% with >15 years, with no difference in screening practices between groups (P = N.S.). Responders screen for HBV as follows: never , 20%, only in the presence of abnormal liver biochemistries , 30%, risk factors or history of hepatitis , 38%. In patients with known HBV, 75% of oncologists refer to specialists, 7% initiate therapy, while 15% do not refer or initiate therapy, most of whom are in an office setting (P = 0.02). Conclusions, Twenty per cent of oncologists never screen for HBV prior to initiating chemotherapy. Office-based physicians were less likely to screen, treat or refer to a specialist prior to chemotherapy. Greater education regarding risk of HBV reactivation is needed for clinicians treating patients with immunosuppressive therapies. Aliment Pharmacol Ther,31, 240,246 [source] Review article: chronic viral infection in the anti-tumour necrosis factor therapy era in inflammatory bowel diseaseALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 1 2010M. J. SHALE Summary Background, Anti-Tumour necrosis factor (TNF) therapy is now well established in the treatment of inflammatory bowel disease and the risk of opportunistic infection is recognized. However, specific considerations regarding screening, detection, prevention and treatment of chronic viral infections in the context of anti-TNF therapy in inflammatory bowel disease are not widely adopted in practice. Aim, To provide a detailed and comprehensive review of the relevance of chronic viral infections in the context of anti-TNF therapy in inflammatory bowel disease. Methods, Literature search was conducted using Medline, Pubmed and Embase using the terms viral infection, hepatitis, herpes, CMV, EBV, HPV, anti-TNF, infliximab, adalimumab, certolizumab pegol and etanercept. Hepatitis B and C and HIV had the largest literature associated and these have been summarized in Tables. Results, Particular risks are associated with the use of anti-TNF drugs in patients with hepatitis B infection, in whom reactivation is common unless anti-viral prophylaxis is used. Reactivation of herpes zoster is the most common viral problem associated with anti-TNF treatment, and may be particularly severe. Primary varicella infection may present with atypical features in patients on anti-TNF. Conclusion, Appreciation of risks of chronic viral disease associated with anti-TNF therapy may permit early recognition, prophylaxis and treatment. [source] The impact of human herpesvirus-6 and -7 infection on the outcome of liver transplantationLIVER TRANSPLANTATION, Issue 8 2002Raymund R. Razonable Human herpesvirus (HHV)-6 and -7 are novel members of the ,-herpesvirus family that maintain latency in the human host after primary infection. Reactivation from latency and/or increased degree of viral replication occurs during periods of immune dysfunction. The clinical effect of HHV-6 and HHV-7 reactivation in recipients of liver transplants is now being recognized. Clinical illnesses such as fever, rash, pneumonitis, encephalitis, hepatitis, and myelosuppression have been described in a number of anecdotal reports. Moreover, a growing body of evidence suggests that the more important effect of HHV-6 and HHV-7 reactivation on the outcomes of liver transplantation may be mediated indirectly by their interactions with the other ,-herpesvirus,cytomegalovirus (CMV). Coinfection among these three ,-herpesviruses in clinical syndromes that were classically ascribed to be solely caused by CMV has been shown and has raised substantial interest in the potential role of HHV-6 and HHV-7 as copathogens in the direct and indirect illnesses caused by CMV. This article reviews the current scientific data on the role and the magnitude of impact of HHV-6 and HHV-7 infection on the outcomes of liver transplantation. [source] Reactivation of horseradish peroxidase with imidazole for continuous determination of hydrogen peroxide using a micro,ow injection,chemiluminescence detection systemLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 4 2003Osamu Nozaki Abstract A method for reactivation of inactivated horseradish peroxidase (HRP) was studied and exploited in an assay for hydrogen peroxide (H2O2). Addition of imidazole into a mobile phase made continuous determination of hydrogen peroxide (H2O2) possible by micro,ow injection based on horseradish-catalysed luminol chemiluminescence. For reproducible determination of H2O2 with HRP, the inactivation of HRP via protonation of the active sites of HRP caused by reaction with H2O2 must be avoided. We successfully reactivated protonated HRP (inactive HRP) with exogenous imidazole in the mobile phase of the micro,ow injection system. The imidazole successfully removed the attached proton from the inactive sites of the HRP. This assay was reproducible (within-run reproducibility, CV = 4.0%) and the detection limit for H2O2 was 5 pmol. Copyright © 2003 John Wiley & Sons, Ltd. [source] Subclinical reactivation of herpes simplex virus type 1 in the oral cavityMOLECULAR ORAL MICROBIOLOGY, Issue 5 2000B. Knaup Reactivation in the oral cavity either symptomatically (recrudescence) or without symptoms (recurrence) may contribute to the transmission of herpes simplex virus type 1 (HSV-1), especially in critical areas of exposure such as dentistry. In order to measure the frequency of HSV-1 reactivation, nested polymerase chain reaction (PCR) was performed on oral swabs collected from 30 healthy people over a period of 58,161 days. In total 19 of 25 (76%) seropositive people were PCR-positive at least once, 6 of these 19 (32%) had recrudescence and 13 (68%) had only asymptomatic reactivation. Frequencies of additional recurrences were higher in people showing symptomatic reactivation than in those who had only recurrences. Recrudescence is a risk factor for elevated levels of asymptomatic HSV-shedding. In most cases HSV-1 was detected only by nested PCR investigated by early onset of therapy or time span before sampling. [source] Reactivation: A severe problem in familial hemophagocytic lymphohistiocytosisPEDIATRICS INTERNATIONAL, Issue 1 2002Omer Devecioglu No abstract is available for this article. [source] Carbon nanotube-supported bimetallic palladium,gold electrocatalysts for electro-oxidation of formic acidPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 5 2010Cheng-Han Chen Abstract It is known that palladium-based catalysts are initially very active in direct formic acid oxidation but they suffer from fast deactivation caused by a strongly adsorbed CO intermediate. Reactivation of the catalysts involving application of anodic potential may cause palladium dissolution. The aim of the present study is to increase the stability and performance of palladium-based catalysts in direct formic acid fuel cells (DFAFCs). Preparation and characterization of palladium/multiwalled carbon nanotubes (Pd/MWCNTs) and towards formic acid oxidation via different treatments are described. The catalysts were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM) and cyclic voltammetry (CV). It was shown that the Pd and Pd,Au MWCNTs supported catalysts after reduction in H2,Ar at 200,°C (R200 treatment) were highly active in formic acid electro-oxidation, whereas the catalysts after heating in argon at 250,°C (C250 treatment) were inactive. The catalysts after hydrogen treatment have smaller metal particles and better contact with MWCNTs support. CV, simulating reactivation of the catalysts, showed that the Pd catalyst suffers from severe Pd dissolution, whereas for the Pd,Au selective leaching of Pd is considerably slower. [source] Treatment-dependent Loss of Polyfunctional CD8+ T-cell Responses in HIV-infected Kidney Transplant Recipients Is Associated with Herpesvirus ReactivationAMERICAN JOURNAL OF TRANSPLANTATION, Issue 4 2009O. Gasser Antiretroviral-therapy has dramatically changed the course of HIV infection and HIV-infected (HIV(+)) individuals are becoming more frequently eligible for solid-organ transplantation. However, only scarce data are available on how immunosuppressive (IS) strategies relate to transplantation outcome and immune function. We determined the impact of transplantation and immune-depleting treatment on CD4+ T-cell counts, HIV-, EBV-, and Cytomegalovirus (CMV)-viral loads and virus-specific T-cell immunity in a 1-year prospective cohort of 27 HIV(+) kidney transplant recipients. While the results show an increasing breadth and magnitude of the herpesvirus-specific cytotoxic T-cell (CTL) response over-time, they also revealed a significant depletion of polyfunctional virus-specific CTL in individuals receiving thymoglobulin as a lymphocyte-depleting treatment. The disappearance of polyfunctional CTL was accompanied by virologic EBV-reactivation events, directly linking the absence of specific polyfunctional CTL to viral reactivation. The data provide first insights into the immune-reserve in HIV+ infected transplant recipients and highlight new immunological effects of thymoglobulin treatment. Long-term studies will be needed to assess the clinical risk associated with thymoglobulin treatment, in particular with regards to EBV-associated lymphoproliferative diseases. [source] Reactivation of motility of demembranated hamster spermatozoa: role of protein tyrosine kinase and protein phosphatasesANDROLOGIA, Issue 2 2002S. B. Patil Summary. Demembranated cauda epididymidal spermatozoa of hamster, following reactivation with 1 mm ATP, exhibited either a loop or planar type of motility. The spermatozoa with planar motility exhibited increased progressive velocity (VSL), straightness (STR), linearity (LIN) and beat cross frequency (BCF) compared to the spermatozoa with loop type motility. cAMP was observed to have differential effects on the motility parameters of the demembranated spermatozoa depending on the type of motility. For instance, in the loop type, average path velocity (VAP), curvilinear velocity (VCL) and VSL were increased in the presence of cAMP unlike in the planar type. Furthermore, in an attempt to understand the role of protein kinases and protein phosphatases in regulation of sperm motility, the effects of various inhibitors of these enzymes on the motility and phosphorylation of proteins of reactivated demembranated spermatozoa were studied. Inhibitors of PTKase (protein tyrosine kinase) and protein phosphatases inhibited the motility of reactivated demembranated hamster spermatozoa. The activity of the respective enzymes associated with demembranated spermatozoa was concurrently inhibited, thus providing evidence that the effect of the inhibitors on motility was mediated through their inhibitory effects on the activities of the enzymes. The results also demonstrated that two phosphotyrosinylated proteins of molecular weight 65 and 80 kDa showed reduced phosphorylation in the presence of PTKase inhibitors, thus indicating their possible role in reactivation of motility of demembranated hamster spermatozoa. [source] Reactivation of Human Brain Homogenate Cholinesterases Inhibited by Tabun using Newly Developed Oximes K117 and K127BASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 3 2009Kamil Kuca Pralidoxime and trimedoxime were chosen as standard reference reactivators. Human tissue was used, as that was closer on the real treatment of human beings. As a result, oxime K127 was found as the best tested reactivator according to the constant kr, characterizing the overall reactivation process. On the contrary, the maximal reactivation ability expressed as percentage of reactivation was the best for trimedoxime. This differences were caused as a result of using the enzyme from different species. Due to this, experiments on human tissue should be conducted after in vitro and in vivo tests on animals to eliminate such important failures of promising oximes. [source] Probing the ,-Helical Structural Stability of Stapled p53 Peptides: Molecular Dynamics Simulations and AnalysisCHEMICAL BIOLOGY & DRUG DESIGN, Issue 4 2010Zuojun Guo Reactivation of the p53 cell apoptosis pathway through inhibition of the p53-hDM2 interaction is a viable approach to suppress tumor growth in many human cancers and stabilization of the helical structure of synthetic p53 analogs via a hydrocarbon cross-link (staple) has been found to lead to increased potency and inhibition of protein,protein binding (J. Am. Chem. Soc. 129: 5298). However, details of the structure and dynamic stability of the stapled peptides are not well understood. Here, we use extensive all-atom molecular dynamics simulations to study a series of stapled ,-helical peptides over a range of temperatures in solution. The peptides are found to exhibit substantial variations in predicted ,-helical propensities that are in good agreement with the experimental observations. In addition, we find significant variation in local structural flexibility of the peptides with the position of the linker, which appears to be more closely related to the observed differences in activity than the absolute ,-helical stability. These simulations provide new insights into the design of ,-helical stapled peptides and the development of potent inhibitors of ,-helical protein,protein interfaces. [source] The Effect of Prior Practice on Memory Reactivation and GeneralizationCHILD DEVELOPMENT, Issue 6 2003Harlene Hayne Three experiments examined the effect of practice on memory performance by 18-month-old infants. Infants were tested using an imitation paradigm; an adult demonstrated a series of actions with objects and infants were given the opportunity to reproduce those actions following a delay. Some infants practiced the target actions before the retention interval (practice) and some did not (no practice). In Experiment 1, a reminder treatment alleviated forgetting by infants who practiced but failed to alleviate forgetting by infants who did not practice. In Experiments 2A and 2B, infants who practiced generalized to novel test stimuli after a 24-hr delay, whereas infants without practice did not. Results suggest practice influences the accessibility and generality of infants' memories. [source] Multiple fixed drug eruption due to drug combinationCONTACT DERMATITIS, Issue 6 2005A. Yokoyama We report the case of a multiple fixed drug eruption (FDE) after taking 1 g of PL® and 100 mg of levofloxacin (Cravit®) at the same time. Patch tests with PL® alone, levofloxacin alone and the combination of PL® and levofloxacin were all negative on the involved and uninvolved sites. Lymphocytic stimulation tests were also negative for PL® alone, levofloxacin alone and the combination of PL® and levofloxacin. Oral provocation tests with PL®alone or levofloxacin alone produced no reactivation. However, we could provoke multiple erythematous plaques on the involved areas by taking a 1/10th dose of the combination of PL® and levofloxacin at the same time. Drug eruption due to a drug combination appears to be very rare. This is the first case of multiple FDE caused by taking PL® -levofloxacin combination. [source] Monitoring cytomegalovirus IE-1 and pp65-specific CD4+ and CD8+ T-cell responses after allogeneic stem cell transplantation may identify patients at risk for recurrent CMV reactivations ,CYTOMETRY, Issue 4 2008Jan W. Gratama Abstract We studied the recovery of CMV-specific CD4+ and CD8+ T-cell immunity in 52 recipients of allogeneic stem cell transplantation (SCT). The proportions of IFN-,-producing CD4+ and CD8+ T cells upon in vitro activation using peptide pools representing the CMV pp65 and IE-1 proteins were assessed at multiple time points post SCT, and correlated with the occurrence of CMV reactivation. In a retrospective analysis, recurrent CMV reactivations occurred in 9 patients and were associated with low pp65-specific CD4+ T-cell and low IE-1-specific CD8+ T-cell reactivities, whereas patients without detectable CMV reactivation (n = 30) or a single reactivation (n = 13) showed a better recovery of these immune responses. CD4+ T-cell responses to IE-1 were infrequent in most patients, whereas CD8+ T-cell responses to pp65 occurred frequently, but did not correlate with protection against (recurrent) reactivation. Prospectively, CMV-specific T-cell responses could be studied prior to 14 reactivation episodes in 8 patients. CD4+ T-cell responses to IE-1 and pp65 were positive in only 1 and 2 episodes, respectively. CD8+ T-cell responses against IE-1 were positive in 4, but against pp65 in 12 episodes, again showing that CD8+ T-cell reactivity against pp65 did not prevent CMV reactivation. Thus, monitoring of particular CMV-specific CD4+ and CD8+ T-cell responses after allogeneic SCT may identify patients at risk for recurrent CMV reactivations. © 2008 Clinical Cytometry Society [source] Prospective study of urine cytology screening for BK polyoma virus replication in renal transplant recipientsCYTOPATHOLOGY, Issue 6 2008M. Koukoulaki Objective:, BK virus (BKV) may be associated with interstitial nephritis in renal transplant recipients and this can lead to irreversible chronic allograft dysfunction. Early diagnosis of BKV nephropathy determines its progress because no specific antiviral therapy exists. Urine cytology, detection of viral DNA in urine or blood and renal biopsy are the main diagnostic tools. The purpose of this study was to evaluate the use of urine cytology for diagnosis of BKV replication in renal graft recipients. Patients and methods:, We studied 32 de novo renal transplant recipients prospectively with sequential urine samples for a period of 1 year. Thin-Prep methodology was used to prepare the slides. Cytology results were correlated with polymerase chain reaction (PCR) in urine and blood. Results:, Decoy cells indicative of BKV infection were detected in 14 (7.3%) of the 190 urine samples derived from 11 recipients. In three cases with positive decoy cells, BK viraemia and viruria were simultaneously identified. In a further three cases, BKV active replication was confirmed in urine by both cytology and PCR. Conclusions:, Urine cytology is an easy and rapid method of detecting decoy cells in cases where renal biopsy is not possible. However, the low incidence of detection of decoy cells in the present study, together with poor correlation with PCR results, questions its sensitivity and specificity in diagnosing BKV reactivation. [source] An Effective Treatment of Dark Lip by Frequency-Doubled Q-Switched Nd:YAG LaserDERMATOLOGIC SURGERY, Issue 1 2001Somyos Kunachak MD Background. Dark lip is a common cosmetic problem in Southeast Asia. There is no known effective treatment. Objective. To propose an effective method for treating dark lips of varying causes with frequency-doubled Q-switched Nd:YAG laser. Methods. Seventy patients with dark lip, of which 22 were congenital, 24 acquired, and 24 of uncertain cause, were treated by frequency-doubled Q-switched Nd:YAG laser at a fluence of 2,3.5 J/cm2 (mode 2.5 J/cm2) after application of topical anesthesia. The endpoint of treatment was complete clearance of the pigment. Follow-up time was 24,36 months (mean 29 months). Results. All patients attained complete clearance of the lesion after an average of 2.5 treatments in the congenital group, 2.2 treatments in the acquired group, and 1.8 treatments in the group with uncertain etiology. The mean (±SD) number of treatments required by the whole group was 2.1 ± 1.4. Recurrence was observed in one case of congenital origin 3 months after the last treatment. In the remaining cases, results persisted up to the time of follow-up. Herpes simplex reactivation was noted in one case 3 days after treatment. There was no dyschromia, scar formation, or change of skin texture. Conclusion. Dark lip can be effectively treated by frequency-doubled Q-switched Nd:YAG laser without major adverse effects. [source] High-dose immunoglobulines and extracorporeal photochemotherapy in the treatment of febrile ulceronecrotic Mucha-Habermann diseaseDERMATOLOGIC THERAPY, Issue 4 2010Federica Marenco ABSTRACT Febrile ulcero-necrotic Mucha-Habermann disease (FUMHD) is a rare subtype of pityriasis lichenoides et varioliformis acuta (only 41 cases described to date), characterized by an acute onset of ulcero-necrotic papules accompanied by high fever and severe constitutional symptoms. We report a case of a 23-year-old man with a steroid-resistant FUMHD treated by intravenous immunoglobulins (IVIG) combined with methotrexate. Only one case of FUMHD treated by IVIG has been reported to date in literature. Also in our case, IVIG proved to be effective in inducing a dramatic improvement of ulceration and in arresting the appearance of new lesions. Moreover, in our experience we decided to perform a maintenance treatment with extracorporeal photochemotherapy (ECP), to the best of our knowledge not previously used in the treatment of pityriasis lichenoides et varioliformis acuta. ECP, which involves extracorporeal exposure of peripheral blood mononuclear cells to photo-activated 8-methoxypsoralen, induces an immunological reaction against auto-reactive T cell clones, without immune-depression and thus could potentially be useful particularly in FUMHD avoiding the risk of an infective reactivation. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||