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21.
Etienne O Gasnier C Taddei C Voegel JC Aunis D Schaaf P Metz-Boutigue MH Bolcato-Bellemin AL Egles C 《Biomaterials》2005,26(33):6704-6712
The surface of medical devices is a common site of bacterial and fungal adhesion, first step to the constitution of a resistant biofilm leading frequently to chronic infections. In order to prevent such complications, several physical and chemical modifications of the device surface have been proposed. Here, we experiment a new type of topical antifungal coating using the layer-by-layer technique. The nanometric multilayer film obtained by this technique is functionalized by the insertion of a chromogranin A-derived antifungal peptide (CGA 47-66, chromofungin). We show that the embedded peptide keeps its antifungal activity by interacting with the fungal membrane and penetrating into the cell. In vitro studies demonstrate that such an antifungal coating is able to inhibit the growth of yeast Candida albicans by 65% and completely stop the proliferation of filamentous fungus Neurospora crassa. The cytotoxicity of such a coating was also assessed by growing human gingival fibroblasts at its surface. Finally, the antifungal coating of poly(methylmethacrylate), a widely used material for biomedical devices, is successfully tested in an in vivo oral candidiasis rat model. Taken together, these results assessed the functionalized multilayer films containing a new potent antifungal non-toxic peptide, as a novel and promising technique for local antifungal protection. 相似文献
22.
Interaction of Dr adhesin with collagen type IV is a critical step in Escherichia coli renal persistence 下载免费PDF全文
Selvarangan R Goluszko P Singhal J Carnoy C Moseley S Hudson B Nowicki S Nowicki B 《Infection and immunity》2004,72(8):4827-4835
The pathogenic mechanism of recurrent or chronic urinary tract infection is poorly understood. Escherichia coli cells bearing Dr fimbriae display unique tropism to the basement membrane (BM)-renal interstitium that enables the bacteria to cause chronic pyelonephritis in experimental mice. The renal receptors for Dr-fimbriated E. coli are type IV collagen and decay-accelerating factor (DAF). We hypothesized that type IV collagen receptor-mediated BM-interstitial tropism is essential for E. coli to cause chronic pyelonephritis. To test the role of the type IV collagen tropism of Dr-fimbriated E. coli in renal persistence, we constructed an isogenic mutant in the DraE adhesin subunit that was unable to bind type IV collagen but retained binding to DAF and examined its virulence in the mouse model. The collagen-binding mutant DrI113T was eliminated from the mouse renal tissues in 6 to 8 weeks, while the parent strain caused persistent renal infection that lasted at least 14 weeks (P < or = 0.02). Transcomplementation with the intact Dr operon restored collagen-binding activity, BM-interstitial tropism, and the ability to cause persistent renal infection. We conclude that type IV collagen binding mediated by DraE adhesin is a critical step for the development of persistent renal infection in a murine model of E. coli pyelonephritis. 相似文献
23.
Charlotte Charpentier Didier Laureillard Mustapha Sodqi Ali Si-Mohamed Marina Karmochkine Laurent Bélec Laurence Weiss Christophe Piketty 《Journal of clinical virology》2008,43(2):212-215
BACKGROUND: Salvage therapy based on foscarnet plus a thymidine analog is effective in patients with advanced-stage HIV disease and viruses harbouring multiple drug-resistance mutations. OBJECTIVE: To identify viral genetic determinants associated with the virological efficacy of foscarnet salvage therapy. STUDY DESIGN: Thirteen patients received foscarnet at a fixed dose of 80mg/kg twice daily for 14 days, in combination with zidovudine or stavudine. RESULTS: The baseline median HIV viral load and CD4 cell count were 5.10log(10)copies/ml and 23cells/mm(3), respectively. Following foscarnet therapy, viral load fell by a median of 1.84log(10)copies/ml (range: -0.29 to -2.82), and by at least 1log(10)copies/ml in 11 patients, all of whom harboured viruses with at least three thymidine-associated mutations (TAMs). The two patients with smaller declines in viral load (<0.50log(10)copies/ml) harboured viruses with only one or zero TAMs. CONCLUSIONS: These findings corroborate, in vivo, the impact of TAMs on HIV susceptibility to foscarnet. The virological response to foscarnet salvage therapy in multiclass-experienced patients may thus differ according to the number of TAMs. 相似文献
24.
Postnatal maturation of mossy fibre excitatory transmission in mouse CA3 pyramidal cells: a potential role for kainate receptors 总被引:2,自引:1,他引:2
Kainate receptors (KARs) are abundantly expressed in the central nervous system at a period of intense synaptogenesis and might participate in the maturation of neural networks. We have described the postnatal development of mossy fibre excitatory synaptic transmission in CA3 pyramidal cells and we have explored the potential role of KARs in synaptic maturation. In CA3 pyramidal cells, mossy fibre stimulation evokes EPSCs as early as postnatal day 3 (P3). At this early stage, mossy fibre (MF)-EPSCs are fully blocked by GYKI 53655, an AMPA receptor (AMPAR) antagonist. A postsynaptic KAR component can only be detected from P6. Thus, AMPAR-EPSCs precede KAR-EPSCs during postnatal maturation at this synapse. All MF-EPSCs display a KAR component after P10. A key issue of the present work is that between P6 and P9, the presence of a postsynaptic KAR component tightly coincides with AMPAR-mediated EPSCs of large amplitude, and with the onset of low frequency facilitation (from 0.1 Hz to 1 Hz), a presynaptic form of short-term synaptic plasticity. In addition, mice lacking functional KARs throughout postnatal development display MF-EPSCs of significantly smaller amplitude at stages of maturation where synaptic KARs are normally present, due to both pre- and postsynaptic impairment of synaptic transmission. These data suggest a role for KARs in the maturation of mossy fibre synapses. 相似文献
25.
Characterization of Mycobacterium tuberculosis complex DNAs from Egyptian mummies by spoligotyping 总被引:1,自引:0,他引:1
Zink AR Sola C Reischl U Grabner W Rastogi N Wolf H Nerlich AG 《Journal of clinical microbiology》2003,41(1):359-367
Bone and soft tissue samples from 85 ancient Egyptian mummies were analyzed for the presence of ancient Mycobacterium tuberculosis complex DNA (aDNA) and further characterized by spoligotyping. The specimens were obtained from individuals from different tomb complexes in Thebes West, Upper Egypt, which were used for upper social class burials between the Middle Kingdom (since ca. 2050 BC) and the Late Period (until ca. 500 BC). A total of 25 samples provided a specific positive signal for the amplification of a 123-bp fragment of the repetitive element IS6110, indicating the presence of M. tuberculosis DNA. Further PCR-based tests for the identification of subspecies failed due to lack of specific amplification products in the historic tissue samples. Of these 25 positive specimens, 12 could be successfully characterized by spoligotyping. The spoligotyping signatures were compared to those in an international database. They all show either an M. tuberculosis or an M. africanum pattern, but none revealed an M. bovis-specific pattern. The results from a Middle Kingdom tomb (used exclusively between ca. 2050 and 1650 BC) suggest that these samples bear an M. africanum-type specific spoligotyping signature. The samples from later periods provided patterns typical for M. tuberculosis. This study clearly demonstrates that spoligotyping can be applied to historic tissue samples. In addition, our results do not support the theory that M. tuberculosis originated from the M. bovis type but, rather, suggest that human M. tuberculosis may have originated from a precursor complex probably related to M. africanum. 相似文献
26.
Gallou C Chauveau D Richard S Joly D Giraud S Olschwang S Martin N Saquet C Chrétien Y Méjean A Correas JM Benoît G Colombeau P Grünfeld JP Junien C Béroud C 《Human mutation》2004,24(3):215-224
von Hippel-Lindau (VHL) disease arises from mutations in the VHL gene and predisposes patients to develop a variety of tumors in different organs. In the kidney, single or multiple cysts and renal cell carcinomas (RCC) may occur. Both inter- and intrafamilial heterogeneity in clinical expression are well recognized. To identify VHL-dependent genetic factors, we investigated the renal phenotype in 274 individuals from 126 unrelated VHL families in whom 92 different VHL mutations were characterized. The incidence of renal involvement was increased in families with mutations leading to truncated protein (MLTP) or large rearrangement, as compared to families with missense changes (81 vs. 63%, respectively; P=0.03). In the latter group, we identified two mutation cluster regions (MCRs) associated with a high risk of harboring renal lesions: MCR-1 (codons 74-90) and MCR-2 (codons 130-136). In addition, the incidence of RCC was higher in families with MLTP than in families with missense changes (75 vs. 57%; P=0.04). Furthermore, mutations within MCR-1 but not MCR-2 conferred genetic susceptibility to develop RCC. Overall, our data argued for a substantial contribution of the genetic change in the VHL gene to susceptibility to renal phenotype in VHL patients. 相似文献
27.
Carbamylcholine, bombesin, pancreozymin, and pentagastrin elicited a similar increase in amylase secretion and phosphatidylinositol turnover in rat pancreatic fragments. The concentration of each secretagogue that provoked half-maximal stimulation of amylase secretion was three to six times lower than that which induced half-maximal stimulation of phosphatidylinositol turnover. The increased turnover of phosphatidylinositols due to carbamylcholine or pancreozymin, but not the secretory response, persisted in a calcium-free medium or in 90% heavy water. The replacement of the media Na+ with Li+ increased an atropine-resistant turnover of phosphatidylinositols, but did not stimulate secretion. The ionophore A-23187 (in a medium containing 2.5 mM Ca2+) and 10 mM NaF induced a high secretory response, but exerted no effect on phosphatidylinositol turnover. K+ at a 70 mM concentration provoked a phosphatidylinositol effect and hypersecretion. Secretin, vasoactive intestinal peptide, dibutyryl cAMP, dibutyryl cGMP, 8-bromo cGMP, and N2-monobutyryl cGMP stimulated amylase secretion without an increased turnover of phosphatidylinositols. It is concluded that, in the rat pancreas, the increased turnover of phosphatidylinositols was directly associated with secretagogues inducing calcium movements. 相似文献
28.
Modulation of Whole-Cell Currents in Plasmodium Falciparum-Infected Human Red Blood Cells by Holding Potential and Serum 总被引:3,自引:0,他引:3
Henry M. Staines Trevor Powell J. Clive Ellory Stéphane Egée Franck Lapaix Gaëtan Decherf Serge L. Y. Thomas Christophe Duranton† Florian Lang† Stephan M. Huber† 《The Journal of physiology》2003,552(1):177-183
Recent electrophysiological studies have identified novel ion channel activity in the host plasma membrane of Plasmodium falciparum -infected human red blood cells (RBCs). However, conflicting data have been published with regard to the characteristics of induced channel activity measured in the whole-cell configuration of the patch-clamp technique. In an effort to establish the reasons for these discrepancies, we demonstrate here two factors that have been found to modulate whole-cell recordings in malaria-infected RBCs. Firstly, negative holding potentials reduced inward currents (i.e. at negative potentials), although this result was highly complex. Secondly, the addition of human serum increased outward currents (i.e. at positive potentials) by approximately 4-fold and inward currents by approximately 2-fold. These two effects may help to resolve the conflicting data in the literature, although further investigation is required to understand the underlying mechanisms and their physiological relevance in detail. 相似文献
29.
Pierre Chatelain Patrick Robberecht Philippe De Neef Monique Deschodt-Lanckman Wolfgang König Jean Christophe 《Pflügers Archiv : European journal of physiology》1980,388(1):21-27
The exact positions of microelectrodes used to measure thePO2 in the cerebral cortex of the rat were determined by staining the tissue with Alcian Blue. The measurement sites were subsequently located under a light microscope and correlated with the capillary and cellular arrangement of the cortex. The microelectrodes used for thePO2 measurements were made of gold glass fibers; the Alcian Blue was injected hydrostatically through a micropipette attached to thePO2 microelectrode. The sites where dye had been deposited were seen under a light microscope as green blue spots about 100 m in diameter. The capillaries were visualized by silver nitrate perfusion. Differences between the localPO2 values in the neo- and the archeocortex were found. In the neocortex the meanPO2 was 31 mm Hg, capillary volume 1.6%, capillary surface area 980/mm2, capillary length 13.5/mm; whereas in the archeocortex these values where 21 mm Hg, 0.9%, 820/mm2 and 9.4/mm respectively. These data indicate a relationship between the microcirculatory transport system and the local oxygen tension and provide further evidence that the meanPO2 level tends to decrease when moving from the surface into the archeocortex.Supported by the Deutsche ForschungsgemeinschaftReported in part at the 3rd Symposium of ISOTT, Cambridge, GB, 1977; and at the 27th International Congress of Physiological Sciences, Paris, France, 1977 相似文献
30.
J C Pector J Winand S Verbeustel M Hebbelinck J Christophe 《The American journal of physiology》1978,234(6):E759-E783
Male rats were submitted for 3 wk either to portacaval shunt or to portacaval transposition. In both cases, sham-operated pair-fed rats served as controls. After an overnight fast, insulinemia was similar in all groups, but glucagonemia was significantly higher (by 65%) and serum glucose significantly lower (by 35%) in rats with a portacaval shunt. The lipid metabolism of epididymal adipose tissue was studied in vitro, as well as in vivo. In rats with a portacaval shunt, in vitro lipogenesis from [U-14C]glucose, [1-14C]acetate, or 3H2o was 60-80% lower than in sham-operated pair-fed controls. Twice as much in vitro basal lipolysis could be determined. In addition, in vivo lipogenesis from 3H2O was markedly decreased (6 times). By contrast, in rats with portacaval transposition, in vitro lipogenesis was higher (by 80-140%) and basal lipolysis lower (by 63%) than in pair-fed controls. Thus, even when the nutritional state was taken into consideration, the type of portal diversion was the determining factor in influencing lipid metabolism in epididymal adipose tissue. 相似文献