The comparative sealing ability of hydroxyapatite cement, mineral trioxide aggregate, and super ethoxybenzoic acid as root-end filling materials

A comparison was made of the ability of hydroxyapatite cement, mineral trioxide aggregate, and super ethoxybenzoic acid to prevent the leakage of bacteria from root canals, when used as root-end filling materials. The materials were tested in a double-chamber device in which a root segment connects the upper (delivery) chamber and the lower (receiving) chamber. The root segment was prepared by having the root canal instrumented to a #45 file, and a 3-mm-deep, root-end preparation placed at the apical foramen. The canal of each root segment was filled with gutta-percha, and the root-end preparation was filled with one of three test materials, mixed according to the manufacturer's directions. Negative controls were constructed with sticky wax sealing the apical foramen. A titered suspension of radioactively (3H-thymidine)-labeled bacteria (Enterococcus fecalis) was placed into the delivery chamber, and sterile saline was placed into the receiving chamber such that the apical third of each root section was immersed. At various time points, samples were taken from the receiving chamber, and measured for 3H activity. The results indicated that (a) all the test materials leaked significantly compared with the negative controls; and (b) there was no significant difference found between the leakage rates of the three materials tested.

Cord blood banking: volume reduction using "Procord" Terumo filter

Cryopreserved cord blood (CB) banking, space storage, and ABO major incompatibility transfusion as well as potential progenitor cell loss during processing, are the subjects of this study. We evaluate processing of fresh and thawed CB on "Procord" (Terumo Corp., Japan). On 16 freshed CBs, mean NC, CD34, CFU-GM yields were, respectively, 54% (SD +/- 20), 75% (SD +/- 25), and 171% (SD +/- 168) in a final volume of 20 ml. Final product was enriched in mononuclear cells (mean 69% granulocytes depletion) with reproducible erythrocyte and platelet depletions means of 97% (SD +/- 1.5) and 93% (SD +/- 8). On seven previous whole frozen CB units, Procord gave comparable red blood cell (98%) depletion with 53% (SD +/- 30) mean CD34 recovery. Procord is an efficient method for erythrocyte depletion of CB, and recoveries of NC and progenitor cells are comparable to those obtained with similar processing. Nevertheless, as all existing methods, it is associated with cell and progenitor cell loss.

S100A6 and S100A11 are specific targets of the calcium- and zinc-binding S100B protein in vivo

In solution, S100B protein is a noncovalent homodimer composed of two subunits associated in an antiparallel manner. Upon calcium binding, the conformation of S100B changes dramatically, leading to the exposure of hydrophobic residues at the surface of S100B. The residues in the C-terminal domain of S100B encompassing Phe(87) and Phe(88) have been implicated in interaction with target proteins. In this study, we used two-hybrid technology to identify specific S100B target proteins. Using S100B as bait, we identify S100A6 and S100A11 as specific targets for S100B. S100A1, the closest homologue of S100B, is capable of interaction with S100B but does not interact with S100A6 or S100A11. S100B, S100A6, and S100A11 isoforms are co-regulated and co-localized in astrocytoma U373 cells. Furthermore, co-immunoprecipitation experiments demonstrated that Ca(2+)/Zn(2+) stabilizes S100B-S100A6 and S100B-S100A11 heterocomplexes. Deletion of the C-terminal domain or mutation of Phe(87) and Phe(88) residues has no effect on S100B homodimerization and heterodimerization with S100A1 but drastically decreases interaction between S100B and S100A6 or S100A11. Our data suggest that the interaction between S100B and S100A6 or S100A11 should not be viewed as a typical S100 heterodimerization but rather as a model of interaction between S100B and target proteins.

Enantiomeric properties of human albumin immobilized on porous silica supports coated with polymethacryloyl chloride

Human serum albumin (HSA) was bound to porous silica, using a reactive polymer derived from polymethacryloyl chloride. Two different procedures were used for coating silica with the polymer. In the first method, the polymer was deposited onto amino-silica by reaction between its reactive functions and NH2 groups on silica. In the second method, the monomer was first linked to the amino-silica and copolymerization with the excess of monomer initiated thereafter. The enantiomeric properties of the resulting supports after the coupling of HSA were compared using different mobile phases. The higher amount of HSA bound using the later method, resulted in higher retention of the enantiomers and better enantioselectivity.

Oncogene and MDR1 gene expression in rat rhabdomyosarcoma sublines of different metastatic potential

The expression of various protooncogenes (myc, Ki-ras, Ha-ras, erbB, fms, sis, jun and fos) and a gene implicated in multidrug resistance (mdr1) was investigated in cell sublines, isolated from a rat rhabdomyosarcoma cell line, and in the corresponding tumors induced by injection of these cells into syngeneic rats. These cell lines and tumors, selected or not by treatment with chlorozotocin (Czt) or adriamycin (Adr), differed in their tumorigenicities and metastatic potentials. Our results showed that 1) an increased expression of some protooncogenes could be correlated with the metastatic potential of tumors; 2) such a correlation was not observed in the cultured cells from which these tumors were derived; 3) mdr1 expression, similarly to that of protooncogenes, was correlated with metastatic potential in all tumors except the Adr-selected tumors.