Search

Resorbable ceramics can promote the bony integration of implants. Their rate of degradation should ideally be synchronized with bone regeneration.This study examined the effect of rapidly resorbable calcium phosphate ceramics 602020, GB14, 305020 on adherence, proliferation and morphology of human bone-derived cells (HBDC) in comparison to β-TCP. The in vitro cytotoxicity was determined by the microculture tetrazolium (MTT) assay. HBDC were grown on the materials for 3, 7, 11, 15 and 19 days and counted. Cell morphology, cell attachment, cell spreading and the cytoskeletal organization of HBDC cultivated on the substrates were investigated using laser scanning microscopy and environmental scanning electron microscopy.All substrates supported sufficient cellular growth for 19 days and showed no cytotoxicity. On each material an identical cell colonisation of well communicating, polygonal, vital cells with strong focal contacts was verified. HBDC showed numerous well defined stress fibres which give proof of well spread and strongly anchored cells. Porous surfaces encouraged the attachment and spreading of HBDC. Further investigations regarding long term biomaterial/cell interactions in vitro and in vivo are required to confirm the utility of the new biomaterials. [ABSTRACT FROM AUTHOR]

Procalcitonin (PCT) has proven to be a very sensitive marker of sepsis for non-leucopenic patients. Little is known about its relevance in immunosuppressed and leucopenic adults. Four hundred and seventy-five PCT determinations were carried out in 73 haematological patients: on 221 occasions the white blood cell (WBC) count was < 1·0 × 109/l and on 239 occasions it was > 1·0 × 109/l leucocytes. Patients were classified as: non-systemic infected controls (n = 280), patients with bacteraemia (n = 32), sepsis (n = 30), severe sepsis (n = 3), septic shock (n = 3) and systemic inflammatory response syndrome (SIRS) (n = 62). When the WBC count was > 1·0 × 109/l, gram-negative bacteria induced higher PCT levels (median 9·4 ng/ml) than gram-positives (median 1·4 ng/ml). In cases with a WBC < 1·0 × 109/l, PCT levels were similar for gram-negative and gram-positive bacteria (1·1 ng/ml versus 0·85 ng/ml). Regardless of the leucocyte count, the median PCT level in bacteraemia cases always remained < 0·5 ng/ml. In heavily leucopenic situations, PCT levels were never > 2 ng/ml even in the sepsis and severe sepsis/septic shock groups, whereas a WBC count > 1·0 × 109/l resulted in median PCT values of 4·1 ng/ml and 45 ng/ml respectively. The positive predictive value for sepsis (cut-off 2 ng/ml) was 93% in cases of WBC count > 1·0 × 109/l, but only 66% in leucopenic conditions. The negative predictive value (cut-off 0·5 ng/ml) was 90% when the WBC count was > 1·0 × 109/l and 63% in leucopenic conditions. Procalcitonin is an excellent sepsis marker with a high positive- and negative-predictive value in patients with WBC count > 1·0 × 109/l, but it does not work satisfactorily below this leucocyte count. [ABSTRACT FROM AUTHOR]