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1.
Evaluation of the VITEK 2 system for identification and antimicrobial susceptibility testing of medically relevant gram-positive cocci 总被引:5,自引:0,他引:5 下载免费PDF全文
Ligozzi M Bernini C Bonora MG De Fatima M Zuliani J Fontana R 《Journal of clinical microbiology》2002,40(5):1681-1686
A study was conducted to evaluate the new VITEK 2 system (bioMérieux) for identification and antibiotic susceptibility testing of gram-positive cocci. Clinical isolates of Staphylococcus aureus (n = 100), coagulase-negative staphylococci (CNS) (n = 100), Enterococcus spp. (n = 89), Streptococcus agalactiae (n = 29), and Streptococcus pneumoniae (n = 66) were examined with the ID-GPC identification card and with the AST-P515 (for staphylococci), AST-P516 (for enterococci and S. agalactiae) and AST-P506 (for pneumococci) susceptibility cards. The identification comparison methods were the API Staph for staphylococci and the API 20 Strep for streptococci and enterococci; for antimicrobial susceptibility testing, the agar dilution method according to the procedure of the National Committee for Clinical Laboratory Standards (NCCLS) was used. The VITEK 2 system correctly identified to the species level (only one choice or after simple supplementary tests) 99% of S. aureus, 96.5% of S. agalactiae, 96.9% of S. pneumoniae, 92.7% of Enterococcus faecalis, 91.3% of Staphylococcus haemolyticus, and 88% of Staphylococcus epidermidis but was least able to identify Enterococcus faecium (71.4% correct). More than 90% of gram-positive cocci were identified within 3 h. According to the NCCLS breakpoints, antimicrobial susceptibility testing with the VITEK 2 system gave 96% correct category agreement, 0.82% very major errors, 0.17% major errors, and 2.7% minor errors. Antimicrobial susceptibility testing showed category agreement from 94 to 100% for S. aureus, from 90 to 100% for CNS, from 91 to 100% for enterococci, from 96 to 100% for S. agalactiae, and from 91 to 100% for S. pneumoniae. Microorganism-antibiotic combinations that gave very major errors were CNS-erythromycin, CNS-oxacillin, enterococci-teicoplanin, and enterococci-high-concentration gentamicin. Major errors were observed for CNS-oxacillin and S. agalactiae-tetracycline combinations. In conclusion the results of this study indicate that the VITEK 2 system represents an accurate and acceptable means for performing identification and antibiotic susceptibility tests with medically relevant gram-positive cocci. 相似文献
2.
Whole cell immobilization of Lactobacillus sp. cells for D -glucose isomerase activity was done by taking well washed cell slurries of bacteria, coating them on rough surfaces of glass rods or glass slides, drying them at 50 °C to 55 °C under infra red lamp and finaly treating with polyvinyl alcohol. The immobilized glucose isomerase activity of cells showed remarkable change in pH optimum, thermal stability, Km and Vmax values as compared to free enzyme of cells. The immobilized enzyme system was employed in the conversion of glucose to fructose using concentrates of amylase-treated corn starch and cellulase-treated bagasse cellulose. 相似文献
3.
膜脂质构成对淋巴细胞膜特性及膜蛋白结构与功能的影响 总被引:1,自引:0,他引:1
本实验通过人为改变淋巴细胞胞膜脂质构成,进而研究了膜脂质,尤其是膜胆固醇,对淋巴细胞膜生物物理特性及膜蛋白结构,以及Ca2+通道蛋白活性的影响。结果显示,随着胞膜磷脂(PL)/胆固醇(Ch)摩尔比的降低,膜脂质的微粘滞性升高,活化淋巴细胞超极化反应增强,胞浆游离钙浓度[Ca2+]i及Ca2+跨膜流动增加,且上述膜电位及Ca2+内流的变化可因Ca2+通道受阻而减弱或消失。提示膜脂质可通过调节Ca2+通道蛋白活性,进而影响Ca2+跨膜内流及膜电位。另外,膜脂质组成改变后,膜蛋白内源性荧光强度及最大发射波长峰位的变化,也表明膜脂质及相关膜特性可影响膜蛋白的结构与功能。 相似文献
4.
Sarda S Nilsson M Balcells M Fernández E 《Journal of biomedical materials research. Part A》2003,65(2):215-221
Calcium phosphate bone cements (CPBCs) represent a potential synthetic alternative to bone-graft materials in bone surgery applications. CPBCs are biocompatible, bioresorbable, and slowly are replaced by new bone in vivo. However, CPBCs do not develop a macroporosity during setting that would allow fast bone ingrowth and good osteointegration of the implant. For this reason, recent research has approached the problem of inducing macroporosity inside the bone cement without influencing its normal setting. In this study, a new method for obtaining injectable macroporous CPBCs is proposed. It is based on the use of sodium dodecyl sulphate (SDS) as an air-entraining agent. The results have shown that the liquid-to-powder ratio and the SDS concentration, as well as the diameter and the interconnectivity of the macropores, can control the micro- and macroporosity. This new technology can be used to develop and optimize new commercial products for osteoporotic bone filling applications. Furthermore, the presented method also can be used at low temperatures before an operation to produce preformed implants to fit the particular needs of a patient. 相似文献
5.
J R Hazel 《The American journal of physiology》1979,236(1):R91-101
Rainbow trout (Salmo gairdneri) acclimated to 5 degrees C possessed larger livers and less neutral lipid per gram of liver than 20 degrees C-acclimated animals; quantities of liver glycolipid, phospholipid, and cholesterol did not vary significantly with acclimation temperature. The relative proportions of phosphatidylethanolamine increased significantly following cold exposure, whereas the quantities of sphingomyelin and cardiolipin declined. For all phosphatides examined (phosphatidylethanolamine, phosphatidylcholine, phosphatidylserine, phosphatidylinositol, lysolecithin, cardiolipin, sphingomyelin) cold acclimation resulted in 1) an increase in the quantity of polyunsaturated fatty acids, 2) a reduction in the level of saturated fatty acids, and 3) little change in the total content of monoenes and dienes. The increased content of polyunsaturated fatty acids in choline and ethanolamine phosphatides following cold acclimation was confined to the 2-position and occurred at the expense of monoenes and dienes. The relative proportions of n - 3 fatty acids, and less frequently n - 6 fatty acids, increased in phosphatides of cold-acclimated trout, whereas the relative proportions of n - 9 fatty acids declined. These data suggest a preferential incorporation of fatty acids belonging to the linolenic acid family at reduced temperatures. Temperature-induced changes in the chemical composition of trout liver phospholipids counteracted the effects of acute temperature change on nonelectrolyte permeability of isolated liposomes. 相似文献
6.
R Pfüller M Mehl R Starke C Hentschel R Grunow G Schmidt R von Baehr 《Journal of basic microbiology》1990,30(10):759-768
For mass cultivation of Candida albicans (serotype A), a fermenter dialysis culture technique is described and compared with shaking culture and fermenter batch culture techniques. Important growth parameters such as yeast dry weight and viable cell counts demonstrate the advantage of the fermenter dialysis culture. Mannan, the major antigen from Candida albicans prepared by phenol-water extraction followed by gel chromatography was tested with the monoclonal IgM antibody H5. 相似文献
7.
M. A. Pence E. McElvania TeKippe M. A. Wallace C.-A. D. Burnham 《European journal of clinical microbiology & infectious diseases》2014,33(10):1703-1712
The rapid identification of yeast is essential for the optimization of antifungal therapy. The objective of our study was to evaluate two matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) platforms, the bioMérieux VITEK MS (IVD Knowledgebase v.2.0) and Bruker Biotyper (software version 3.1), for the rapid identification of medically relevant yeast. One hundred and seventeen isolates, representing six genera and 18 species, were analyzed using multiple direct smear methods to optimize identification. Sequence analysis was the gold standard for comparison. Isolates were analyzed with VITEK MS using the direct smear method +/? a 25 % formic acid on-plate extraction. For Biotyper, isolates were analyzed using direct smear without formic acid, and with 25 % and 100 % formic acid on-plate extractions. When all methods were included, VITEK MS correctly identified 113 (96.6 %) isolates after 24 h with one misidentification, and Biotyper correctly identified 77 (65.8 %) isolates using a threshold of ≥2.0 with no misidentifications. Using a revised threshold of ≥1.7, Biotyper correctly identified 103 (88.0 %) isolates, with 3 (2.6 %) misidentifications. For both platforms, the number of identifications was significantly increased using a formic acid overlay (VITEK MS, p?0.01; Biotyper, p?0.001), and reducing the Biotyper threshold from ≥2.0 to ≥1.7 significantly increased the rate of identification (p?0.001). The data in this study demonstrate that the direct smear method with on-plate formic acid extraction can be used for yeast identification on both MS platforms, and more isolates are identified using the VITEK MS system (p?0.01). 相似文献
8.
Hypometabolism as the ultimate defence in stress response: how the comparative approach helps understanding of medically relevant questions 下载免费PDF全文
T. A. Gorr 《Acta physiologica (Oxford, England)》2017,219(2):409-440
First conceptualized from breath‐hold diving mammals, later recognized as the ultimate cell autonomous survival strategy in anoxia‐tolerant vertebrates and burrowing or hibernating rodents, hypometabolism is typically recruited by resilient organisms to withstand and recover from otherwise life‐threatening hazards. Through the coordinated down‐regulation of biosynthetic, proliferative and electrogenic expenditures at times when little ATP can be generated, a metabolism turned ‘down to the pilot light’ allows the re‐balancing of energy demand with supply at a greatly suppressed level in response to noxious exogenous stimuli or seasonal endogenous cues. A unifying hallmark of stress‐tolerant organisms, the adaptation effectively prevents lethal depletion of ATP, thus delineating a marked contrast with susceptible species. Along with disengaged macromolecular syntheses, attenuated transmembrane ion shuttling and PO2‐conforming respiration rates, the metabolic slowdown in tolerant species usually culminates in a non‐cycling, quiescent phenotype. However, such a reprogramming also occurs in leading human pathophysiologies. Ranging from microbial infections through ischaemia‐driven infarcts to solid malignancies, cells involved in these disorders may again invoke hypometabolism to endure conditions non‐permissive for growth. At the same time, their reduced activities underlie the frequent development of a general resistance to therapeutic interventions. On the other hand, a controlled induction of hypometabolic and/or hypothermic states by pharmacological means has recently stimulated intense research aimed at improved organ preservation and patient survival in situations requiring acutely administered critical care. The current review article therefore presents an up‐to‐date survey of concepts and applications of a coordinated and reversibly down‐regulated metabolic rate as the ultimate defence in stress responses. 相似文献
9.
10.
Intraepidermal and dermal-epidermal cohesion are of paramount importance for the integrity of the skin. Some constituent
molecules of keratinocyte adhesion complexes and basement membrane-associated structures are the targets of antibody-mediated
autoimmune reactions that give rise to various (muco-)cutaneous blistering diseases. The current state of our knowledge about
these molecules – along with the main clinical, histological, and immunohistochemical features of the corresponding autoimmune
diseases and their pathogenetic mechanisms – comprise the subjects surveyed in this review. Among the desmosomal cadherins
(desmogleins and desmocollins) that mediate epidermal cell–cell adhesion, it has been demonstrated that desmoglein 1 and desmoglein
3 are the autoantigens of pemphigus foliaceus and pemphigus vulgaris, respectively, both diseases that result in intraepidermal
blistering. Further, desmocollin autoantibodies may be involved in IgA pemphigus. Paraneoplastic pemphigus is associated with
autoantibodies directed against the desmosomal plaque protein, desmoplakin. Of the constituents of hemidesmosomes, the plaque
protein, BP230 (BPAG1), and the collagen-like transmembrane protein, BP180 (BPAG2), are the autoantigens of bullous pemphigoid
and pemphigoid gestationis, the manifestations of both of which include subepidermal blistering. Several diseases arise from
autoimmune reactions against certain proteins associated with the basement membrane located beneath hemidesmosomes, for example
laminin 5 (cicatricial pemphigoid), ladinin (LAD-1; linear IgA disease), uncein, and collagen VII (epidermolysis bullosa acquisita),
the last of which is the constituent protein of the anchoring fibrils. Such recent advances in the elucidation of the molecular
nature of autoantigens may serve as the basis for the development of novel molecule-based therapeutic strategies.
Received: 12 September1997 / Accepted: 27 October 1997 相似文献
11.
The possible regulatory mechanisms by which glycosphingolipid- and cholesterol-rich membrane microdomains, caveolar and non-caveolar lipid rafts, control the immune response are continuously expanding. In the present overview we will focus on how these membrane-organizing lipids are involved, in collaboration with tetraspanin proteins, in the formation of distinct MHC-I and MHC-II microdomains at the cell surface and will analyze the possible roles of MHC compartmentation in the processes of antigen presentation and regulation of various stages of the cellular immune response. Some basic, lipid raft- and tetraspan mediated mechanisms involved in the formation and function of immunological synapses between various APCs and T-cells will also be discussed. Finally, a new aspect of immune regulation by sphingolipids will be briefly described, namely how can the death or stress signals, leading to ceramide accumulation, result in raft-associated regulatory platforms controlling cell death or antigen-induced, TCRmediated signaling of T-lymphocytes. The influence of these signals and their cross-talk on the fate (death or survival) of T-cells and the outcome of T-cell response will also be discussed. 相似文献
12.
By radical polymerization, 7-(N-acryloyl-N-methyl)-3-dimethyliminio-3H-phenothiazine chloride ( 1 ) has been transformed in the N-substituted polyacrylamide carrying Azure B side groups, poly{1-[N-(3-dimethyliminio-3H-phenothiazin-7-yl)-N-methylaminocarbonyl]ethylene chloride}. On addition of poly(acrylic acid) dye-polymer interactions and metachromasy phenomena have been examined using absorption spectrometry. Similarly, 1 has been copolymerized with acrylic acid. Intramolecular functional interaction causes a bathochromic absorption band (652 nm) which persists partially on addition of poly(acrylic acid), and affects dye-aggregation and metachromasy. 相似文献
13.
Serysheva VV Borisova MP Mezhevikina LM Poltavtseva RA Sukhkih GT 《Bulletin of experimental biology and medicine》2002,134(6):534-537
We studied the effect of leukemia-inhibiting factor on bilayer lipid membranes. Leukemia-inhibiting factor in a concentration of 10 ng/ml nonspecifically increased membrane permeability for ions. Leukemia-inhibiting factor acts as a surface-active substance on bilayer lipid membranes. 相似文献
14.
Reagents (immobilized anti-alpha-fetoprotein discs) having a porous structure were prepared for enzyme immunoassay of alpha-fetoprotein by radiation polymerization at low temperatures. Discs were attached to sticks for easy handling. The activity (determined by absorbance at 492 nm) of the discs varied with the hydrophilic properties and size of the disc. The discs are sufficiently sensitive and precise for enzyme immunoassay of alpha-fetoprotein. 相似文献
15.
Stahtea XN Kousidou OCh Roussidis AE Tzanakakis GN Karamanos NK 《Connective tissue research》2008,49(3):211-214
Critical steps for cancer cell growth, migration, invasion, and metastasis are the interactions of extracellular matrix (ECM) molecules with cells, the disconnection of intercellular adhesion, and the degradation of ECM. The latter is mediated mainly by metalloproteinases (MMPs), the expression and activation of which is related to various tyrosine kinase receptors (RTKs). The aberrant RTK activity is associated with the development and progress of various human cancers. Tyrosine kinase inhibitors (TKIs) are small molecules which compete with ATP for binding to the kinase domain of the RTKs and have been used for the treatment of solid tumors. In this review, the recent advances of the effects of TKIs on MMPs expressed by solid tumors are presented. 相似文献
16.
Merocyanine 540 as a flow cytometric probe of membrane lipid organization in leukocytes 总被引:1,自引:0,他引:1
Merocyanine 540 (MC540) is a fluorescent probe that binds preferentially to membranes with loosely packed lipids. When combined with flow cytometry, it provides a novel methodology for rapidly and quantitatively assessing lipid organization in individual leukocytes. Analysis of cells stained simultaneously with MC540 and 1-[4-trimethylammoniumphenyl]-6-phenyl-1,3,5-hexatriene, to normalize for surface area, revealed that all leukocytes in peripheral blood bind equivalent amounts of dye per unit surface area. This result indicates that the lipids of the plasma membranes of all types of circulating cells are organized similarly. Upon activation with appropriate stimuli, lymphocytes, monocytes, and neutrophils all bound increased amounts of dye per unit surface area, indicating a change in lipid organization to a less-ordered state. Cells stained with MC540 were sorted on the basis of their fluorescence intensity yielding populations homogeneous with respect to lipid organization. Thus not only can MC540 and flow cytometry be combined for analyzing the organization of lipids in individual leukocytes, but sorted populations can be obtained for further biochemical, structural, and functional analyses. 相似文献
17.
Performance of the new VITEK 2 GP card for identification of medically relevant gram-positive cocci in a routine clinical laboratory 下载免费PDF全文
The VITEK 2 gram-positive (GP) identification card (bioMerieux, Marcy l'Etoile, France) has been redesigned to achieve greater accuracy in the identification of gram-positive cocci. A total of 43 biochemical tests, including 17 enzymatic tests, are present in the card and interpreted in a kinetic mode, for up to 8 h. The VITEK 2 database, used in conjunction with the GP identification card, allows the identification of 115 different taxa. A total of 364 strains of GP cocci (217 Streptococcaceae strains and 147 Micrococcaceae strains) belonging to 31 taxa were tested with the new VITEK 2 GP identification card. Of the 364 strains, 105 were taken from routine primary plating media. A total of 344 strains (94.5%) were correctly identified to the species level and 17 strains (4.7%) were identified with low discrimination, requiring additional tests, whereas 1 strain (0.3%) was incorrectly identified and 2 strains (0.5%) remained unidentified. Within 7 h of the start of incubation, more than 90% of all strains were identified. Of the 105 primary cultures, 97% were correctly identified to the species level, 2% were identified with low discrimination, and 1% remained unidentified. Identification performance data were independent of each of the three plating media used. It is concluded that the new VITEK 2 GP identification card provides reliable results for the identification of GP cocci under routine laboratory conditions. 相似文献
18.
Biodegradable microparticles represent a promising carrier system for the efficient delivery of therapeutic macromolecules to phagocytic professional antigen-presenting cells (APC). Solid lipid microparticles (SLM) consisting of a tripalmitin matrix were prepared using a novel micromixer-based solvent extraction process. A positive surface charge was introduced by the incorporation of cationic lipids into the formulation. All obtained SLM were efficiently phagocytosed by primary macrophages in vitro. Complete intracellular degradation was observed already within 24 h, making SLM a suitable carrier for the immediate delivery of therapeutics to APC. Cationic SLM adsorbed plasmid DNA and bovine serum albumin (BSA) used as a model protein, and triggered the cellular internalization of the macromolecules by phagocytic macrophages. Surprisingly, the cationic SLM also triggered the internalization of these molecules by non-phagocytic 293 cells. This was probably due to the detachment of nanocomplexes formed of cationic lipid and DNA or BSA, respectively, from the surface of DNA- or BSA-loaded SLM and their subsequent uptake into the cells. Transfection efficiency of the DNA-loaded SLM was most pronounced in non-phagocytic cells and was not detected in the macrophage cell line or in primary macrophages. Our further studies revealed that cytotoxic effects of cationic SLM were more pronounced in the phagocytic cells, which could be explained by the very rapid uptake and degradation of the cationic SLM in these cells. In conclusion, SLM may provide a new, efficient means for the immediate intracellular delivery of therapeutic macromolecules into APC. Caution is warranted for cationic carriers, which may accentuate cytotoxic effects in the phagocytic cells. 相似文献
19.
K Barabas J A Sizensky W P Faulk 《American journal of reproductive immunology (New York, N.Y. : 1989)》1991,25(3):120-123
We have used transferrin-adriamycin conjugates to deliver drug to transferrin receptors and have shown that the conjugates bind to and kill tumor cells in vivo and in vitro. This has been studied with the use of qualitative and quantitative assays. In this report, we present evidence indicating that the primary target of transferrin-adriamycin cytotoxicity is the plasma membrane. This was done using a spectrofluorometric method that takes advantage of the fluorescence properties of adriamycin. It was shown that, while DNA intercalation may be the primary mechanism of cytotoxicity for free adriamycin, transferrin-adriamycin conjugates were not observed to interact with nuclear DNA. This may be a useful consideration in the design of future chemotherapeutic studies with transferrin conjugates of anticancer drugs. 相似文献
20.
A highly sensitive and reproducible enzyme-linked immunosorbent assay (ELISA) for the detection of anti-RNA antibodies is described. The assay procedure involves adsorption of total cellular RNA on nylon beads which could be conveniently stored for a considerable period of time without loss in antigenicity. Sixty-four percent of systemic lupus erythematosus (SLE) sera were positive for anti-RNA antibodies with fluorogenic substrate against 48% with colorigenic substrate. 相似文献