Calcium silicate/calcium phosphate biphasic cements for vital pulp therapy: chemical-physical properties and human pulp cells response.

OBJECTIVES: The aim was to test the properties of experimental calcium silicate/calcium phosphate biphasic cements with hydraulic properties designed for vital pulp therapy as direct pulp cap and pulpotomy. METHODS: CaSi-αTCP and CaSi-DCDP were tested for ion-releasing ability, solubility, water sorption, porosity, ability to nucleate calcium phosphates, and odontoblastic differentiation­alkaline phosphatase (ALP) and osteocalcin (OCN) upregulation­of primary human dental pulp cells (HDPCs). RESULTS: The materials showed high Ca and OH release, high open pore volume and apparent porosity, and a pronounced ability to nucleate calcium phosphates on their surface. HDPCs treated with CaSi-αTCP showed a strong upregulation of ALP and OCN genes, namely a tenfold increase for OCN and a threefold increase for ALP compared to the control cells. Conversely, CaSi-DCDP induced a pronounced OCN gene upregulation but had no effect on ALP gene regulation. CONCLUSIONS: Both cements showed high biointeractivity (release of Ca and OH ions) correlated with their marked ability to nucleate calcium phosphates. CaSi-αTCP cement proved to be a potent inducer of ALP and OCN genes as characteristic markers of mineralization processes normally poorly expressed by HDPCs. CLINICAL RELEVANCE: Calcium silicate/calcium phosphate cements appear to be attractive new materials for vital pulp therapy as they may provide odontogenic/dentinogenic chemical signals for pulp regeneration and healing, and dentin formation in regenerative endodontics.

Manganese peroxidase isoenzymes produced by Pleurotus ostreatus grown on wood sawdust.

The white rot basidiomycete Pleurotus ostreatus produces two manganese peroxidase (MnP) isoenzymes when grown in solid stationary conditions on poplar sawdust, whereas a lower production of these same enzymes is observed on fir sawdust. Addition of Mn(2+) to poplar culture resulted in a threefold increase of MnP activity; the same addition to fir culture was able to increase tenfold the MnP production. The two MnP isoenzymes (MnP2 and MnP3) were purified from P. ostreatus poplar culture. The isoenzymes differ in their pI values, molecular masses, and N-terminal sequences. MnP3 has the same N-terminal sequence as that of a P. ostreatus MnP previously reported. Both isoenzymes exhibit Mn(2+)-dependent and Mn(2+)-independent peroxidase activities when tested on phenolic substrates. The gene coding for the new isoenzyme MnP2 was cloned and sequenced and the promoter region analyzed. Furthermore, the chromosomal localization of all known P. ostreatus genes was determined.