2,514 research outputs found
Sphingosine mediates FTY720-induced apoptosis in LLC-PK1 cells
FTY720, a synthetic sphingoid base analog, was examined as a new sphingosine kinase inhibitor, which converts endogenous sphingosine into its phosphate form. With 20 ??M of FTY720, sphingosine accumulated in the LLC-PK1 cells in a time- and dose-dependent manner. The FTY720 treated cells showed a high concentration of fragmented DNA, a high caspase-3 like activity and TUNEL staining cells. It was also found that the sphingosine and sphinganine level increased in a time- and dose-dependent manner within 12 h after the FTY720 treatment. The sphingosine kinase activity was reduced by FTY720 as much as other sphingosine kinase inhibitors, N, N-dimethylsphingosine (DMS), dl-threo-dihydrosphingosine (DHS). The fragmented DNA content as a result of the 20 ??M of FTY720 treatment and by 5 ??M of the exogenously added BSA-sphingosine complex indicated typical apoptosis. Under similar conditions, the accumulated sphingosine concentration in all the cells was almost identical even though the sphingosine distribution inside the cells was somewhat different. These results indicate that the FTY720 induced apoptosis is associated with the inhibition of the sphingosine kinase activity and is strongly associated with the successive accumulation of sphingosine.open172
Electrical conductivity and electromagnetic interference shielding of multiwalled carbon nanotube composites containing Fe catalyst
Thin and flexible composite films of raw or purified multiwalled carbon nanotube (MWCNT) with various mass fractions and poly(methylmethacrylate) (PMMA) were synthesized for electromagnetic interference (EMI) shielding material. From scanning electron microscopy and high-resolution transmission electron microscopy photographs, we observed the formation of a conducting network through MWCNTs in an insulating PMMA matrix and the existence of an Fe catalyst in MWCNTs. The dc conductivity (sigma(dc)) of the systems increased with increasing MWCNT mass fraction, showing typical percolation behavior. The measured EMI shielding efficiency (SE) of MWCNT-PMMA composites by using the extended ASTM D4935-99 method (50 MHz-13.5 GHz) increased with increasing MWCNT mass fraction as sigma(dc). The highest EMI SE for raw MWCNT-PMMA composites was similar to27 dB, indicating commercial use for far-field EMI shielding. The contribution of absorption to total EMI SE of the systems is larger than that of reflection. Based on magnetic permeability, we suggest raw MWCNTs and their composites can be used for near-field EMI shielding.open28629
Development of cordycepin formulations for preclinical and clinical studies
There is extensive literature on in vivo studies with cordycepin but these studies were generally conducted without validation of the various formulations, especially in terms of the solubility of cordycepin in the dosing vehicles used. Cordycepin is a promising drug candidate in multiple therapeutic areas and there is a growing interest in studies aimed at assessing the pharmacological activity of this compound in relevant animal disease models. It is likely that many reported in vivo studies used formulations in which cordycepin was incompletely soluble. This can potentially confound the interpretation of pharmacokinetics and efficacy results. Furthermore, the presence of particles in intravenously administered suspension can cause adverse effects and should be avoided. Here we present the results from our development of simple and readily applicable formulations of cordycepin based on quantitative solubility assessment. Homogeneous solutions of cordycepin were prepared in phosphate-buffered saline (PBS) at different pH levels, suitable as formulations for both intravenously and oral administration. For the purpose of high-dose oral administration we also developed propylene glycol (PPG)-based vehicles in which cordycepin is completely soluble. The stability of the newly developed formulations was also assessed, as well the feasibility of their sterilisation by filtration. Additionally, an HPLC-UV method for the determination of cordycepin in the formulations, which may also be useful for other purposes, was developed and validated. Our study could provide useful information for improvement of future preclinical and clinical studies involving cordycepin
Ethylene supports colonization of plant roots by the mutualistic fungus Piriformospora indica
The mutualistic basidiomycete Piriformospora indica colonizes roots of mono- and dicotyledonous plants, and thereby improves plant health and yield. Given the capability of P. indica to colonize a broad range of hosts, it must be anticipated that the fungus has evolved efficient strategies to overcome plant immunity and to establish a proper environment for nutrient acquisition and reproduction. Global gene expression studies in barley identified various ethylene synthesis and signaling components that were differentially regulated in P. indica-colonized roots. Based on these findings we examined the impact of ethylene in the symbiotic association. The data presented here suggest that P. indica induces ethylene synthesis in barley and Arabidopsis roots during colonization. Moreover, impaired ethylene signaling resulted in reduced root colonization, Arabidopsis mutants exhibiting constitutive ethylene signaling, -synthesis or ethylene-related defense were hyper-susceptible to P. indica. Our data suggest that ethylene signaling is required for symbiotic root colonization by P. indica
The Cell Shape-determining Csd6 Protein from Helicobacter pylori Constitutes a New Family of L,D-Carboxypeptidase
Helicobacter pylori causes gastrointestinal diseases, including gastric cancer. Its high motility in the viscous gastric mucosa facilitates colonization of the human stomach and depends on the helical cell shape and the flagella. In H. pylori, Csd6 is one of the cell shape-determining proteins that play key roles in alteration of cross-linking or by trimming of peptidoglycan muropeptides. Csd6 is also involved in deglycosylation of the flagellar protein FlaA. To better understand its function, biochemical, biophysical, and structural characterizations were carried out. We show that Csd6 has a three-domain architecture and exists as a dimer in solution. The N-terminal domain plays a key role in dimerization. The middle catalytic domain resembles those of L,D-transpeptidases, but its pocket-shaped active site is uniquely defined by the four loops I to IV, among which loops I and III show the most distinct variations from the known L,D-transpeptidases. Mass analyses confirm that Csd6 functions only as an L,D-carboxypeptidase and not as an L,D-transpeptidase. The D-Ala-complexed structure suggests possible binding modes of both the substrate and product to the catalytic domain. The C-terminal nuclear transport factor 2-like domain possesses a deep pocket for possible binding of pseudaminic acid, and in silico docking supports its role in deglycosylation of flagellin. On the basis of these findings, it is proposed that H. pylori Csd6 and its homologs constitute a new family of L,D-carboxypeptidase. This work provides insights into the function of Csd6 in regulating the helical cell shape and motility of H. pylori.1165Ysciescopu
Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis Associated with Acetaminophen Use during Viral Infections
An association between drug treatment for viral infections and severe cutaneous adverse reactions has been noted. We investigated six patients diagnosed with Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) after being prescribed acetaminophen for suspected viral illnesses. Multiplex analysis was performed to measure cytokine levels in sera before and after treatment. IL-2Ralpha levels significantly decreased during the convalescence phase. Although acetaminophen is relatively safe, the drug can trigger SJS/TEN in patients with suspected viral infections. T-cells and monocytes may be key components of the link between viral infection and acetaminophen-induced SJS/TEN
A case of IgG4-related disease with bronchial asthma and chronic rhinosinusitis in Korea.
IgG4-related disease (IgG4-RD) is characterized by a systemic involvement of
tumor-like lesions with IgG4-positive plasmacytes. We experienced a case of
IgG4-RD developed in a patient with bronchial asthma (BA) and chronic
rhinosinusitis (CRS). A 55-yr-old female patient with BA and CRS complained of
both eyes and neck swelling as well as a recurrent upper respiratory infection in
recent 1 yr. The serum levels of IgG4, creatinine, and pancreatic enzymes were
elevated. A biopsy of the submandibular gland showed an abundant infiltration of
IgG4-positive plasmacytes. Her symptoms remarkably improved after the treatment
of a systemic steroid that has been maintained without recurrence. We report a
rare case of IgG4-RD developed in a patient with BA and CRS
Performance of the CMS Cathode Strip Chambers with Cosmic Rays
The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device
in the CMS endcaps. Their performance has been evaluated using data taken
during a cosmic ray run in fall 2008. Measured noise levels are low, with the
number of noisy channels well below 1%. Coordinate resolution was measured for
all types of chambers, and fall in the range 47 microns to 243 microns. The
efficiencies for local charged track triggers, for hit and for segments
reconstruction were measured, and are above 99%. The timing resolution per
layer is approximately 5 ns
Immunologic evaluation of immediate hypersensitivity to cefaclor
PURPOSE: Cefaclor is widely prescribed for various infectious diseases. As its
consumption increases, the number of hypersensitivity reactions to cefaclor has
increased. This study aimed to evaluate the immunologic findings of immediate
hypersensitivity to cefaclor. MATERIALS AND METHODS: We enrolled 47 patients with
immediate hypersensitivity to cefaclor from Ajou University Hospital and Asan
Medical Center. Serum specific IgE, IgG1, and IgG4 antibodies to cefaclor-human
serum albumin (HSA) conjugate were measured by enzyme-linked immunosorbent assay
(ELISA). RESULTS: The most common phenotype was anaphylaxis (Group I, 78.7%),
followed by urticaria (Group II, 21.3%). The detection of specific IgE, IgG1, and
IgG4 to cefaclor-HSA conjugate by ELISA tended to be higher in Group I (40.5%,
41.7%, 21.6%) than in Group II (20.0%, 20.0%, 0%) with no statistical
significance. Significant associations were found between specific IgE and IgG1
or IgG4 (p<0.001, p=0.019). ELISA inhibition tests showed significant inhibitions
by both free cefaclor and cefaclor-HSA conjugate. For basophil activation tests
in patients having no specific IgE antibody, the CD63 expression level on
basophils increased with incubations of free cefaclor. CONCLUSION: The most
common manifestation of immediate hypersensitivity to cefaclor was anaphylaxis,
most of which was mediated by IgE; however, a non-IgE mediated direct basophil
activation mechanism was suggested in a subset of anaphylaxis patients
Antibiotic Resistance Pattern and Molecular Epidemiology of Methicillin-Resistant Staphylococcus aureus Colonization in Burns Unit of a Tertiary Care Hospital in Peshawar, Pakistan
Purpose: To develop strategies for the control of hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) which is a serious threat to burns patients with the aid of molecular studies.Methods: Staphylococcus aureus strains were collected from the Burns Unit of Khyber Teaching Hospital (KTH) Peshawar, Pakistan from July - December 2011. Antibiotic resistance was determined according to the recommendations of Clinical Laboratory Standard Institute (CLSI). Molecular epidemiology of the S. aureus strains were determined by pulse field gel electrophoresis (PFGE).Results: PFGE identified 14 clusters which included 29 different pulso-types prevailing in the Burns Unit. Of the 29 types, 11 contained two or more strains of the same pulso-type. These MRSA isolates were highly resistant to various kinds of penicillin and cephalosporin (85 – 100 %). Among the important anti-staphylococal agents tested, 17 % of the isolates were resistant to fusidic acid and linezolid. All the 54 strains were susceptible to vancomycin.Conclusion: Several of the same pulso-types prevail in the Burns Unit of KTH. Furthermore, 29 pulsotypes mong the 54 strains suggest the diversity of the MRSA strains collected from burns patients.Keywords: Epidemiology, Pulso-type, Fusidic acid, Linezolid, Vancomycin, Methicillin-resistant Staphylococcus aureus, Burn
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