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排序方式: 共有333条查询结果,搜索用时 15 毫秒
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Mucoadhesive Microspheres Containing Amoxicillin for Clearance of Helicobacter pylori 总被引:5,自引:0,他引:5
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Naoki Nagahara Yohko Akiyama Masafumi Nakao Mayumi Tada Megumi Kitano Yasuyuki Ogawa 《Antimicrobial agents and chemotherapy》1998,42(10):2492-2494
In an effort to augment the anti-Helicobacter pylori effect of amoxicillin, mucoadhesive microspheres, which have the ability to reside in the gastrointestinal tract for an extended period, were prepared. The microspheres contained the antimicrobial agent and an adhesive polymer (carboxyvinyl polymer) powder dispersed in waxy hydrogenated castor oil. The percentage of amoxicillin remaining in the stomach both 2 and 4 h after oral administration of the mucoadhesive microspheres to Mongolian gerbils under fed conditions was about three times higher than that after administration in the form of a 0.5% methylcellulose suspension. The in vivo clearance of H. pylori following oral administration of the mucoadhesive microspheres and the 0.5% methylcellulose suspension to infected Mongolian gerbils was examined under fed conditions. The mucoadhesive microspheres and the 0.5% methylcellulose suspension both showed anti-H. pylori effects in this experimental model of infection, but the required dose of amoxicillin was effectively reduced by a factor of 10 when the mucoadhesive microspheres were used. In conclusion, the mucoadhesive microspheres more effectively cleared H. pylori from the gastrointestinal tract than the 0.5% methylcellulose suspension due to the prolonged gastrointestinal residence time resulting from mucoadhesion. A dosage form consisting of mucoadhesive microspheres containing an appropriate antimicrobial agent should be useful for the eradication of H. pylori. 相似文献
3.
Miura-Yokota Y Matsubara Y Ebihara T Hattori S Irie S 《Connective tissue research》2004,45(2):109-121
Collagen purified from the mantle muscle of the Japanese common squid, Todarodes pacificus, showed autodegradation during incubation under acidic conditions at 25 degrees C, without the addition of exogenous enzymes. This suggests that the collagenolytic proteases bind to collagen tightly through the steps of collagen preparation. Collagenolytic activity also was detected in a crude extract of mantle muscle, and leupeptin and E-64 were observed to inhibit collagenolytic activity within the collagen fraction and muscle extract. We purified these collagenolytic cysteine proteases by leupeptin column chromatography and cellulose acetate membrane electrophoresis. Optimal enzymatic activity was observed at pH 3.5, and collagenolytic activity was completely suppressed at neutral or alkaline pH. The purified enzymes were 28 kDa and 25 kDa in size, and both had gelatinolytic activity, as detected by gelatin zymography, and cut the specific site of denatured collagen alpha chain. The purified enzymes degraded squid collagen at 25 degrees C, which is 2.5 degrees lower than the temperature at which squid collagen normally denatures; however, the proteases were ineffective at 20 degrees C. Interestingly, the isolated proteases were capable of digesting both squid and bovine gelatin. In this article, we describe collagenolytic cysteine proteases that bind to the collagen of Todarodes pacificus, thereby digesting it by attacking microunfolding regions generated by incubation 2-3 degrees C below the denaturation temperature. 相似文献
4.
Kimiko Amanuma Toku Kanaseki Yohko Ikeuchi Shoji Ohkuma Tatsuya Takano 《Virchows Archiv : an international journal of pathology》1987,410(3):231-238
Summary The fine structure of intracellular and extracellular lipids in the atherosclerotic aorta of Watanabe-heritable hyperlipidemic (WHHL) rabbits was demonstrated by a quick-freeze etching technique. Many lipid droplets, with and without a membrane, were observed in the foam cells. Membrane-free droplets were observed as onionlike structure with a concentric lamellar structure surrounded by 10 nm filaments. Droplets surrounded by a limited membrane probably correspond to lipid-laden lysosomes.In the extracellular connective tissue space, marked accumulation of lipids with a vesicular structure was seen among collagen fibers. The appearance of these lipids was similar to that of lipids in lysosomes of foam cells. 相似文献
5.
Katagiri H Kawai Y Sugizaki N Sakai K Handa M Okamoto S Watanabe K 《Rinsho byori. The Japanese journal of clinical pathology》2003,51(6):516-521
Thrombotic thrombocytopenic purpura(TTP) is a multisystem disorders characterized by thrombocytopenia, microangiopathic hemolytic anemia associated with red cell fragmentation, and neurological and renal symptoms. Plasma of patients with TTP has been shown to contain unusually large von Willebrand factor(vWF) multimers that may cause platelet agglutination in vivo. Recently, a metalloprotease responsible for cleavage of vWF multimers has been isolated from normal human plasma and was found to be deficient in some patients with TTP. We examined the activity of the vWF-cleaving protease(vWF-CP), by modified Furlan's method, in plasma from patients with a familial TTP, 3 acquired TTP, 4 thrombotic microangiopathy(TMA) and 2 veno-occlusive disease(VOD) associated after allo-BMT. Diluted plasma samples of patients were incubated with protease-free vWF purified from normal human plasma, in the presence of urea and barium ions. The extent of vWF degradation was assayed by electrophoresis in SDS-agarose gels and immunoblotting. Activity of vWF-CP from 12 normal plasma have been shown as 77-180%(average 115%), whereas, no vWF-CP(below 5%) was observed in plasma from familial TTP, before and after plasma exchange, although FFP infusion therapy has been effective for this patient to recover thrombocytopenia. In 3 acquired TTP, 2 patients showed lack of vWF-CP activity in plasma, and inhibitors against vWF-CP have been elucidated by plasma cross-mixing test. After extensive plasma exchange and FFP infusion followed by corticosteroid therapy, normal vWF-CP was recovered in plasma from 2 acquired TTP patients. Among BMT patients, plasma from 4 BMT-TMA showed normal vWF-CP activities as 55-111%, whereas plasma from 2 BMT-VOD revealed low vWF-CP activity, as 24% and 37%, respectively. Thus, measurement of vWF-CP is crucial to predict differentiation of primary forms of TMA to establish the pathogenesis in varied endothelial dysfunction. 相似文献
6.
Katagiri YU Ohmi K Tang W Takenouchi H Taguchi T Kiyokawa N Fujimoto J 《Laboratory investigation; a journal of technical methods and pathology》2002,82(12):1735-1745
SUMMARY: Raft microdomains are glycolipid-enriched microdomain scaffolding molecules involved in signal transduction. The binding of Shiga toxin to globotriaosyl ceramide in raft microdomains of the human renal tubular cell line ACHN causes temporal activation of Src-kinase Yes. To study the downstream signaling mechanism proceeding to the activation of Yes, we raised monoclonal antibodies (MAbs) against raft microdomains. The MAbs were screened on the basis of, first, binding to raft microdomains with dot-blot immunostaining, second, intracellular localization of the epitope by flowcytometry after permeabilization, and third, translocation of the antigen molecules after Stx treatment by immunohistochemical staining. Raft.1 MAb bound to the molecules that accumulated to the particular region near the nucleus after Stx treatment. Two-dimensional Western blotting and matrix-assisted laser desorption/ionization time of flight mass spectrometry analysis revealed that the antigen molecule is GTP binding protein beta subunits 1 and 2 (Gbeta1 and 2). That Raft.1 recognized Gbeta1 and 2 was further confirmed by the reactivity to recombinant Gbeta1 and 2 proteins. To our knowledge, this is the first report of production of a MAb recognizing Gbeta1 and 2. Because Gbeta1 and 2 are highly conserved all through organisms and are deeply involved in signal transduction, Raft.1 is expected to be utilized frequently in research. 相似文献
7.
Tachikawa Tetsuhiko; Kohno Yohko; Matsui Yoichiro; Yoshiki Shusaku 《Carcinogenesis》1986,7(6):885-892
To examine early intercellular junction changes caused by treatmentwith 9, 10-dimethyl-l, 2-benzanthracene (DMBA), rat lingualepithelium was cultivated in isolation and observed by electrophysiological,freeze-fracture and whole-mount electron microscopy. Electrophysiologicalmeasurements showed a transient decrease in membrane potentialof -10.2 mV 6 h after the treatment. It returned to almost thesame level as that of the control group 1 day later. Six hoursafter treatment, input resistance decreased rapidly to 5.3 Mbut increased to 18.0 M 12 h after treatment. Transient reductionof input resistance and membrane potential occurred prior tothe decrease in the coupling ratio 6 h after treatment withDMBA. In freeze-fracture replicas, the number of gap junctionsdecreased by 45% of the control value 6 h after treatment withDMBA. At 12 h and thereafter, the number and area of gap junctionssubsequently decreased by 6080% of the control value.Alterations in the number and area of desmosomes were similarto those of the gap junctions. The formation of epithelial cytoskeletons,partially devoid of the 24 and 58 nm filamentswas also observed. A decrease in the density of filament networksbeneath the plasma membranes was especially apparent. Treatmentwith a carcinogen brought about morphological cellular changesas early as 6 h after treatment, and such early changes mighttrigger metabolic cellular abnormalities. Affected cells appearto move away from normal cells in a process of repeated destructionand revision of intercellular junctions, and cytoskeletons. 相似文献
8.
Ryuichi Fukuyama Yohko Murakawa Stanley I. Rapoport 《Molecular and chemical neuropathology / sponsored by the International Society for Neurochemistry and the World Federation of Neurology and research groups on neurochemistry and cerebrospinal fluid》1994,23(2-3):93-101
To understand the possible role of amyloid precursor protein (APP) in human lymphocytes, and the regulation of APP gene expression in this cell type, we determined levels of cellular APP protein and of mRNA in human T-cell-derived Jurkat cells that were treated with lectin, phorbol ester, and calcium ionophore. We also related these levels to cell aggregation and adhesion. Cell-cell aggregation and cell-plastic adhesion were observed over a 24-h period after incubating cells for 2 h with phytohemagglutinin or phorbol myristate acetate. Cells treated with a calcium ionophore showed no aggregation or adhesion. Western blots indicated no obvious alteration in the level of cellular APP with different treatments. Northern blots showed a significant transient increase of APP mRNA after incubation with the calcium ionophore, whereas phorbol ester treatment showed a slight increase of APP mRNA. We analyzed the level of APP mRNA in human peripheral T cells which had been separated from peripheral lymphocytes. The level increased transiently by up to threefold after treatment with calcium ionophore plus phorbol esters. These data suggest that cell-cell aggregation and cell-matrix adhesion by human lymphocytes are not associated with an increased level of cellular APP protein or of mRNA. 相似文献
9.