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排序方式: 共有1193条查询结果,搜索用时 93 毫秒
1.
Patrizia Casaline Delia Mezzanzanica Olga Valota Elena Adobati Antonella Tomassetti Maria I. Colnaghi Silvana Canevari 《Journal of cellular biochemistry》1995,58(1):47-55
The monoclonal antibody MOv19 directed to a folate binding protein shows temperature-dependent potentiation of binding of the noncompeting monoclonal antibody MOv18 to the relevant antigen, but the mechanism involved in this phinomenon had remained unclear. Use of chimeric versions of both monoclonal antibodies and the F(ab′)2 and fan fragments of MOv19 revealed an increment in MOv18 binding in all combinations irrespective of the orgin of the Fc portin of the monoclonal antibody. The potentiating effect of bivalent MOv19 fragments on 125l-MOv18 binding was similar to that of the entire monoclonal antibody and occurred at saturating concentrations of both reagents at which monovalent binding prevails. Similarly, the monovalent fragment also induced a significant increase in MOv18 bunding. Howener, the potentiation sccurred only at very high concentrations of antibody fragment. Homologous inhibition was drastically reduced using MOv19 Fab fragment, suggesting a low binding stability of the monovalent reagent. Immunoblotting analysis and binding in the presence of exogenous purified folate binding protein indicated a cross-linking between soluble and cell surface molecules mediated by the bivalent monoclonal antibodies. The extentof the increase in MOv18 binging at O°C with high amounts of exogenous folate binding protein was lower than that obtained at 370C in the absence of added molecule. Release of 125l-MOv18 from the cell surface was significantly higher in the absence of MOv19 than in its presence. Affinity constant values of 125l-MOv18 binding evaluated in the presence of MOv19 or control monoclonal antibody MINT5 were comparable, whereas the number of binding sites per cell detected by 125l-MOv18 was significantly higher in the presence of MOv19 than MINT5. Together, the data suggest that monoclonal antibody MOv19 induces a conformational change of the molecule it binds that increases the number of antigenic sites anvailable for MOv18 binding and, in turn, the binding stability of the latter, MOv19 bivalency also contributes to the MOv18 binding increment by cross-linking released and cell surface–anchored folate binding protein molecules. © Wiley-Liss, Inc. 相似文献
2.
Silvana Molossi Mariano Elices Thomas Arrhenius Marlene Rabinovitch 《Journal of cellular physiology》1995,164(3):620-633
We previously reported infiltration of immune-inflammatory cells in coronary arteries from cardiac allografts, associated with increased endothelial and smooth muscle cell fibronectin synthesis regulated by interleukin (IL)-1b?. We now investigate, using a porcine endothelial-smooth muscle cell co-culture system, whether IL-1b?-stimulated fibronectin production is functionally important in lymphocyte transendothelial migration. Lymphocytes were harvested from porcine peripheral blood and, in the unactivated state or following activation with phorbol myristic acetate (PMA) and IL-2, were characterized by fluorescence-activated cell sorter (FACS) analysis and added to a confluent endothelial monolayer on the upper chamber of a transwell system. Endothelial cells, as well as smooth muscle cells (in the bottom of the chamber), were stimulated with IL-1b?. Then transendothelial lymphocyte migration was determined in the presence of CS1 and RGD (fibronectin) peptides, blocking α4b?1 and α5b?1 integrin receptors on lymphocyte surfaces, respectively. A 55-70% inhibition of lymphocyte migration was observed when compared to control peptides. The combination of CS1 and RGD peptides did not significantly enhance the inhibitory effect of either peptide alone. A similar decrease in lymphocyte transendothelial migration toward smooth muscle cells was documented using a monoclonal antibody to cellular fibronectin. Furthermore, using smooth muscle cell conditioned medium; we reproduced the enhanced transendothelial lymphocyte migration as well as the inhibition with blocking peptides or fibronectin antibodies. Our data suggest that cytokine-mediated fibronectin synthesis in vascular cells recruits inflammatory cells through interactions of specific peptides with cell surface α4b?1 α5b?1 integrins. © 1995 Wiley-Liss, Inc. 相似文献
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Alvar Carranza Camila de Mello Andrés Ligrone Silvana González Pablo Píriz Fabrizio Scarabino 《Biological invasions》2010,12(5):995-998
We report on the first sightings of the invasive Rapa Whelk Rapana venosa in Maldonado Bay (Punta del Este Harbor and Gorriti Island) using in vivo, underwater observations and video surveys. The
species was first detected in the Río de la Plata (Uruguay and Argentina) in 1999, and by 2004 it had extended its local distribution
to Punta del Este at the eastern boundary of the estuary. Observations performed by SCUBA diving showed that R. venosa is preying on native mussels Mytilus edulis and Brachidontes spp., and that formerly abundant mussel beds are being seriously depleted due to a combination of human extraction, habitat deterioration
and predation by the Rapa Whelk. 相似文献
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The early intracellular signaling pathway for the insulin/insulin-like growth factor receptor family in the mammalian central nervous system 总被引:8,自引:0,他引:8
Franco Folli Silvana Ghidella Luca Bonfanti C. Ronald Kahn Adalberto Merighi 《Molecular neurobiology》1996,13(2):155-183
Several studies support the idea that the polypeptides belonging to the family of insulin and insulin-like growth factors
(IGFs) play an important role in brain development and continue to be produced in discrete areas of the adult brain. In numerous
neuronal populations within the olfactory bulb, the cerebral and cerebellar cortex, the hippocampus, some diencephalic and
brainstem nuclei, the spinal cord and the retina, specific insulin and IGF receptors, as well as crucial components of the
intracellular receptor signaling pathway have been demonstrated. Thus, mature neurons are endowed with the cellular machinery
to respond to insulin and IGF stimulation. Studies in vitro and in vivo, using normal and transgenic animals, have led to
the hypothesis that, in the adult brain, IGF-I not only acts as a trophic factor, but also as a neuromodulator of some higher
brain functions, such as long-term potentiation and depression. Furthermore, a trophic effect on certain neuronal populations
becomes clearly evident in the ischemic brain or neurodegenerative disorders. Thus, the analysis of the early intracellular
signaling pathway for the insulin/IGF receptor family in the brain is providing us with new intriguing findings on the way
the mammalian brain is sculpted and operates. 相似文献
7.
Giuseppe Corace Cristina Angeloni Marco Malaguti Silvana Hrelia Paul C. Stein Martin Brandl 《Journal of liposome research》2014,24(4):323-335
The purpose of this study was the development of multifunctional liposomes for nasal administration of tacrine hydrochloride. Liposomes were prepared using traditional excipients (cholesterol and phosphatidylcholine), partly enriched with α-tocopherol and/or Omega3 fatty acids. This approach was chosen in order to obtain at the same time two positive results: an enhanced drug permeation through nasal mucosa and a concomitant neuroprotective effect. Several liposome formulations were prepared using the Reverse Phase Evaporation technique followed by membrane filter extrusion. In particular, liposome capacity to enhance drug permeation was evaluated by means of membrane permeation and cellular uptake studies. Furthermore, liposome effect on neuronal viability and intracellular ROS production was evaluated as well as their cytoprotective effect against oxidative stress. All liposome formulations showed a mean diameter in the range of 175?nm to 219?nm with polydispersity index lower than 0.22, a lightly negative zeta potential and excellent encapsulation efficiency. Moreover, along with good mucoadhesive properties, multifunctional liposomes showed a markedly increase in tacrine permeability, which can be related to liposome fusion with cellular membrane, a hypothesis, which was also supported by cellular uptake studies. Finally, the addition of α-tocopherol without Omega3 fatty acids, was found to increase the neuroprotective activity and antioxidant properties of liposomes. 相似文献
8.
Conservation of peculiar structural properties by the hemoglobins of anguilloid eels (Teleostei) 总被引:1,自引:0,他引:1
M. Rizzotti Silvana Pagni Flegra Bentivegna 《Journal of Zoological Systematics and Evolutionary Research》1990,28(1):12-19
The three species investigated, the European eel, Anguilla anguilla (L.), the Mediterranean moray, Muraena helena L., and the conger eel, Conger coner (L.), represent three different superfamilies of the suborder Anguilloidei (infradivision Elopomorpha). Their hemoglobin systems show peculiar structural properties, which distinuish them from all other teleost species studied. They present acidic and basic components differing greatly in their isoelectric points; the basic components have the highest isoelectric points detected in teleost hemoglobins. While there is one major basic component, multiplicity is present in the acidic components in Muraena and Conger. The polyeptides of the acidic comonents show the same electrophoretic mobility in 8 M urea. In the three species, the electroploretic mobility with urea-SDS of the hemoglobin polypeptides shows a shorter β polypeptide in the basic components. These features had never been investigated among Elopomorpha, and are likely to be phylogenetically relevant. 相似文献
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