[Re-mineralization ability of Galla chinensis extracts on root carious lesions with or without non-collagen proteins].

OBJECTIVE: To evaluate the re-mineralization ability of Galla Chinensis extracts (GCE) on two artificial carious lesions in bovine root de-mineralized in vitro. METHODS: Fourteen bovine root blocks were divided into two parts from buccal to lingual direction. The mesial blocks were treated with a demineralization solution and the distant blocks were treated with another demineralization solution. Two specimens from each group were selected randomly and examined with polarization microscope (PLM). After all blocks were demineralized, half surface of the demineralized zone was covered and the another half was treated with 0.5% NaCl to extract soluble dentin phosphate protein (S-DPP). Then all specimens were submitted to pH-cycling for one week. In the first four days, all specimens were treated with GCE for 21 h and with demineralization solution for 3 h. In the remaining three days, all specimens were treated with GCE. The re-mineralization ability of GCE on the specimens was evaluated by laser scanning confocal microscope (LSCM). RESULTS: There existed intact surface layers on subsurface lesions but no surface layers were produced on erosive lesions. The re-mineralization ability of GCE on erosive lesions improved significantly with the treatment of 0.5% NaCl solution (P < 0.05). But it had no significant effect on subsurface lessions. CONCLUSION: Extraction of S-DPP with 0.5% NaCl can improve the re-mineralization ability of GCE on root caries with erosive lesions. This finding supports the proposition that Galla Chinesis may be a promising anti-caries natural medicine in the future.

Proliferation, differentiation and characterization of osteoblasts from human BM mesenchymal cells.

BACKGROUND: The objective of this study was to isolate osteoprogenitor cells (OPC) from BM mesenchymal stromal cells (MSC) and test their capacity to proliferate and differentiate into osteoblasts. METHODS: Human MSC were separated on a Percoll gradient and cultured in DMEM supplemented with 15% human serum, and characterized by flow cytometric analyzes for CD34, CD13, CD90, CD105 and CD117. To induce differentiation, cultured cells were exposed to 10(-7) m dexamethasone (dexa) and/or 10(-3) m sodium beta-glycerophosphate (beta-GlyP) and 1,25-dihydroxyvitamin D3 (calcitriol) or 9-cis-retinoic acid (9-RA). RESULTS: alkaline phosphatase (AP) activity was detected in cells irrespective of the dexa and/or beta-GlyP treatment. Antigenic phenotypes of MSC were CD34- (more than 99%) and CD13+ CD90+ CD105+ CD117+ (c. 50%). The treatment induced extracellular calcium deposition and gene and protein expression of osteonectin (ON) and bone sialoprotein (BSP): beta-GlyP induced an increase (c. 2.2-fold) of the ON gene and dexa augmented (c. 2.7-fold) the gene expression of BSP II. Gene expression of BSP I reached a maximum at 3 weeks of combined treatment. Osteocalcin gene expression was induced only after additional treatment with calcitriol or 9-RA. Ultrastructural analysis revealed the secretory phenotype of OPC. DISCUSSION: Under appropriate treatment, MSC can give rise to OPC that have the capacity to differentiate into osteoblasts characterized by the expression of osteogenic markers, osteoblastic properties and stromal BM cells phenotypes. These cells may represent a promising material to be utilized in orthopedic cellular therapy.

Isolation and characterization of a sialo-glycopeptide from buffalo colostrum.

A sialoglycopeptide was isolated from buffalo colostrum in pure form by chromatography on Sephadex G-25 and QAE-Sephadex A-25. This was found to be homogeneous by cellulose acetate membrane electrophoresis and reverse phase HPLC. It consisted of fucose, galactose, mannose, N-acetyl glucosamine and N-acetyl neuraminic acid in the ratio 1:2:3:4:1, and aspartic acid, serine, threonine, proline and glutamic acid were the major amino acids. Glycine was identified as the N-terminal amino acid residue. The structure elucidation of the carbohydrate moiety was carried out by methylation analysis, mass spectrometry. 1H-NMR spectroscopy and the probable structure was revealed to be that of a complex biantennary type.

Identification, characterization, cloning, and expression of apolipoprotein C-IV, a novel sialoglycoprotein of rabbit plasma lipoproteins.

We have identified and characterized a novel proline- and arginine-rich protein component of lipoproteins, present in up to five sialylated isoforms, in rabbit blood plasma. The pI of the desialylated protein is 5.7. Based upon its N-terminal sequence, a complete cDNA sequence of 555 nucleotides was cloned from rabbit liver. The synthesized protein is predicted to contain 124 amino acids, including a typical signal peptide of 27 residues. The mature protein of 97 amino acids, designated apolipoprotein C-IV, is associated with the lipoproteins of blood plasma, primarily very low density and high density lipoproteins. It contains two potential amphipathic helices characteristic of plasma apolipoproteins and forms discoidal micelles with phosphatidylcholine. Northern analysis shows a single 0.6-kilobase apolipoprotein C-IV mRNA, detected only in the liver, and Southern analysis suggests a single copy gene. Sialylated apolipoprotein C-IV is secreted from transfected mammalian cells. Nucleotide sequence comparisons demonstrate a strong homology to portions of the upstream regions of the mouse and human apolipoprotein C2 genes, within each of which a distinct gene has recently been identified. The nucleotide sequences and the predicted amino acid sequences, as well as corresponding cDNA sequences in the rat and monkey, indicate that the apolipoprotein C4 gene has been highly conserved during mammalian evolution.

Lymphotactin: a cytokine that represents a new class of chemokine.

In this study, the cytokine-producing profile of progenitor T cells (pro-T cells) was determined. During screening of a complementary DNA library generated from activated mouse pro-T cells, a cytokine designated lymphotactin was discovered. Lymphotactin is similar to members of both the Cys-Cys and Cys-X-Cys chemokine families but lacks two of the four cysteine residues that are characteristic of the chemokines. Lymphotactin is also expressed in activated CD8+ T cells and CD4-CD8- T cell receptor alpha beta + thymocytes. It has chemotactic activity for lymphocytes but not for monocytes or neutrophils. The gene encoding lymphotactin maps to chromosome one. Taken together, these observations suggest that lymphotactin represents a novel addition to the chemokine superfamily.

Clonal dental pulp cells (RDP4-1, RPC-C2A) synthesize and secrete osteopontin (SPP1, 2ar).

Dental pulp cells play an important role in maintaining dental mineralized tissue throughout life. Supplementary mineralization such as reparative dentin and pulp stone frequently occurs after primary dentin formation. Dental pulp cells are thought to be closely associated with such mineralization. We found that clonal rat dental pulp cells, RDP4-1 and RPC-C2A, produce and secrete osteopontin, but do not synthesize phosphophoryn which is a major noncollagenous protein found in dentin. The dental pulp osteopontin was highly phosphorylated and identified by thrombin susceptibility and immunoprecipitation with osteopontin/2ar antibody. Osteopontin synthesis markedly increased by 12-O-tetradecanoylphorbol-13-acetate (TPA) as observed in many osteoblastic cells. This study indicates that these cells can produce osteopontin as a major phosphoprotein and suggests that the synthesis of osteopontin could be used as a characteristic marker of dental pulp cells.

Chemical and biological properties of B16 murine melanoma cells grown in defined medium containing bovine serum albumin.

The addition of 1 percent (w/v) bovine serum albumin (BSA) to the F12 medium utilized for the growth of the B16 melanoma cells significantly stimulated the growth of this cell line. The synthesis of mucopolysaccharides and sialoglycopeptides in this medium is identical with that in Eagle's minimal essential medium with Earle's balanced salt solution supplemented with 2 mM L-glutamine, twice the recommended concentration of vitamins, nonessential amino acids, sodium pyruvate, and 10 percent (v/v) fetal calf serum. Cell volume and morphology did not change significantly, under the different growth conditions and tumorigenicity, as assayed by injection of cultured cells into syngeneic animals, was not decreased. Analysis of the BSA used indicated the presence of a sialoglycoprotein contaminant. This sialoglycoprotein contaminant was present in all lots examined and contains N-acetyl-and N-glycolylneuraminic acid, mannose, galactose, and glucosamine. The sialoglycoprotein can be removed by chromatography on acetate form anion-exchange resin at pH 4.3. F12 media containing the purified BSA plus selenite and the sodium salts of palmitic, oleic, and linoleic acids supported growth of the melanoma cells to the same extent as did the media containing unpurified BSA, indicating that the sialoglycoprotein has no role in sustaining the growth of the cells.