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Gradual Release (gradual + release)
Selected AbstractsRegeneration of canine peroneal nerve with the use of a polyglycolic acid,collagen tube filled with laminin-soaked collagen sponge: a comparative study of collagen sponge and collagen fibers as filling materials for nerve conduitsJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 6 2001Toshinari Toba Abstract A novel artificial nerve conduit was developed and its efficiency was evaluated on the basis of promotion of peripheral nerve regeneration across an 80-mm gap in dogs. The nerve conduit was made of a polyglycolic acid,collagen tube filled with laminin-soaked collagen sponge. Conduits filled with either sponge- or fiber-form collagen were implanted into an 80-mm gap of the peroneal nerve (five dogs for each form). Twelve months postoperatively nerve regeneration was superior in the sponge group both morphometrically (percentage of neural tissue: fiber: 39.7 ± 5.2, sponge: 43.0 ± 4.5, n=3) and electrophysiologically (fiber: CMAP 1.06 ± 0.077, SEP 1.32 ± 0.127 sponge: CMAP 1.04 ± 0.106, SEP 1.24 ± 0.197, n=5), although these differences were not statistically significant. The observed regeneration was complementary to successful results reported previously in the same model, in which collagen fibers exclusively were used. The results indicate a possible superiority of collagen sponge over collagen fibers as filling materials. In addition, the mass-producibility, superior scaffolding potential, and capacity for gradual release of soluble factors of the sponge provide make it an attractive alternative to fine fibers, which are both technologically difficult and costly to produce. This newly developed nerve conduit has the potential to enhance peripheral nerve regeneration across longer gaps commonly encountered in clinical settings. © 2001 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 58: 622,630, 2001 [source] Co-localization of PARP-1 and lamin B in the nuclear architecture: A halo-fluorescence- and confocal-microscopy studyJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 3 2005Melita Vidakovi Abstract A functional interaction between poly(ADP-ribose) polymerase-1 (PARP-1) and lamin B has recently been proposed by nuclear fractionation, crosslinking, and immunoprecipitation experiments. Here we use fluorescence microscopy to verify and extend these findings. We analyze nuclear halo preparations by fluorescence in situ immuno staining (FISIS), which shares attributes with traditional nuclear fractionation techniques, and by confocal laser scanning microscopy (CLSM). The results agree in that a major part of the enzyme co-localizes with lamin B under physiological conditions, where PARP-1 only has basal activity. After DNA damage and the associated activation of PARP-1, and during the subsequent entry into apoptosis, dramatic changes occur: a gradual release of the enzyme from the lamina, accompanied by its accumulation in nucleoli. Our observations are in line with biochemical evidence for lamin B-PARP-1 interactions under physiological conditions and suggest ways by which these interactions are modified to support PARP-functions in damage and its fate in apoptosis. © 2005 Wiley-Liss, Inc. [source] A novel and simple type of liposome carrier for recombinant interleukin-2JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 3 2001Eri Kanaoka The strong interaction between recombinant interleukin-2 (IL-2) and liposome was characterized and its possible application to drug-delivery control considered. The liposomes were prepared with egg phosphatidylcholine, distearoyl-phosphatidylglycerol (DSPG), dipalmitoyl-phosphatidylcholine, dipalmitoyl-phosphatidylglycerol or distearoyl-phosphatidylcholine (DSPC). Small and hydrophobic liposomes were selected, which were composed of saturated and long-fatty-acid-chain phospholipids. When the composition and the mixture ratio of IL-2 and the liposome were optimized, more than 95% of the lyophilized IL-2 (Imunace, 350000, JRU) was adsorbed consistently onto the DSPC-DSPG liposome (molar ratio, 10:1; 25 ,mol mL,1; 30 nm in size). Merely mixing IL-2 lyophilized with liposome suspension is convenient pharmaceutically. After intravenous administration to mice, liposomal IL-2 was eliminated half as slowly from the systemic circulation as free IL-2, with more than 13 and 18 times more IL-2 being delivered to the liver and spleen, respectively. After subcutaneous administration of liposomal IL-2 to mice, the mean residence time of IL-2 in the systemic circulation was 8 times that of free IL-2. These results show that IL-2 consistently adsorbs onto the surface of liposomes after optimization of its composition and mixing ratio. Intravenous and subcutaneous administration to mice demonstrates the gradual release of IL-2. Further trials are warranted using these liposomes. [source] Gelling of Alumina Suspensions Using Alginic Acid Salt and Hydroxyaluminum DiacetateJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2002Andre R. Studart This paper proposes a novel direct casting method of alumina suspensions using alginic acid salt and the coagulation agent hydroxyaluminum diacetate (HADA). These two compounds allowed the consolidation of alumina suspensions through a simultaneous time-delayed physical and chemical gelation process. The physical gel was formed by the gradual release of aluminum and acetate ions from the HADA in water, while the chemical gel originated from the cross-linking of alginate molecules by the polyvalent aluminum ions. Wet alumina green bodies displayed enhanced mechanical properties with the addition of minimal contents of organic material (<0.1 wt%). [source] | ||||||||||