Effect of electrochemical structuring of Ti6Al4V on osteoblast behaviour in vitro.

Topography and surface chemistry have a profound effect on the way in which cells interact with an implant, which in turn impacts on clinical use and performance. In this paper we examine an electrochemical polishing approach in H2SO4/methanol that can be applied to the widely used orthopaedic/dentistry implant material, Ti6Al4V, to produce structured surfaces. The surface roughness, as characterized by R(a), was found to be dependent on the time of electropolishing but not on the voltage parameters used here. The surface chemistry, however, was dependent on the applied electrochemical potential. It was found that the chemical composition of the surface layer was modified during the electrochemical process, and at high potentials (9.0 V) a pure TiO2 layer of at least 10 nm was created on top of the bulk alloy. Characterization of these surfaces with rat cells from the osteoblast lineage provided further evidence of contact guidance by microscale topography with morphology analysis correlating with surface roughness (R(a) 300­550 nm). Formation of a bone-like matrix after long-term culture on these surfaces was not strongly dependent upon R(a) values but followed the voltage parameter. These findings suggest that the surfaces created by treatment at higher voltages (9.0 V) produced a nanoscale layer of pure TiO2 on the Ti6Al4V surface that influenced the programme of cellular differentiation culminating in osteogenesis.

Tissue distribution of amyloid P component as defined by a monoclonal antibody produced by immunization with human glomerular basement membranes.

A monoclonal antibody reactive against amyloid P component (NCL-AMP) has been developed following immunization of mice with partially-purified human glomerular basement membranes (GBM) and standard hybridization and cloning techniques. The antibody reactivity was evaluated by enzyme-linked immunosorbent assay (ELISA) and by the indirect immunoperoxidase technique on sections of frozen and fixed human kidney and other tissues. The distribution of amyloid P component in various normal tissues is described and the possible co-localization with the Goodpasture antigen is discussed. In addition, the suitability of the antibody for detection of amyloid deposits in renal amyloidosis is demonstrated and its potential for use in other pathological conditions is considered.

c-erbB-2 oncoprotein expression in mammary and extramammary Paget's disease: an immunohistochemical study.

Over-expression of the c-erbB-2 oncogene occurs in a proportion of human adenocarcinomas and in breast carcinoma is associated with poorer prognosis. Sections of formalin-fixed, paraffin-embedded tumour tissue from 22 patients with mammary and extramammary Paget's disease have been stained immunohistochemically using a monoclonal antibody (NCL-CB11) raised against a synthetic peptide from the C-terminal end of the predicted sequence of the c-erbB-2 protein product. All 12 cases of mammary Paget's disease showed membrane staining of intra-epidermal cells, indicating c-erbB-2 over-expression. Sections of underlying ductal breast carcinoma were available in nine cases; all nine tumours were c-erbB-2 positive and in eight the in situ component was of comedo or solid type. There was membrane staining of tumour cells in four of the 10 cases of extramammary Paget's disease; staining intensity was generally weaker than that observed in the cases of mammary disease. The possible implications of these findings for the histogenesis of both mammary and extramammary Paget's disease are discussed.

NCL-CB11, a new monoclonal antibody recognizing the internal domain of the c-erbB-2 oncogene protein effective for use on formalin-fixed, paraffin-embedded tissue.

The c-erbB-2 proto-oncogene encodes a 190 k Mr protein representing a putative growth factor receptor with considerable homology to the EGF receptor. Gene amplification and overexpression of the oncogene protein have been demonstrated in a variety of tumours including breast cancer, where it is associated with a poor prognosis. In this study we have produced and characterized a mouse monoclonal antibody, designated NCL-CB11, to the c-erbB-2 protein. NCL-CB11 was generated to a synthetic peptide sequence corresponding to a site of predicted antigenicity near the C-terminus of the internal domain of the protein. NCL-CB11 produces intense membrane-associated immunohistochemical staining in a proportion of human cancer cells. The specificity of the antibody is supported by Western blotting and immunoprecipitation studies. Reactivity with an internal site of the protein is confirmed by the necessity of cell permeabilization for reactivity in fluorescence-activated cell sorter (FACS) analysis. A high degree of correlation between immunohistochemical staining using NCL-CB11, and c-erbB-2 gene amplification has been observed. NCL-CB11 should prove to be a valuable reagent for investigations into the pathological significance of c-erbB-2 protein expression.

Sodium and potassium intake and blood pressure.

Sodium and potassium intakes were increased in normotensive volunteers to assess the effects on their blood pressures. An approximately threefold increase in sodium intake for eight days had no effect on the blood pressures of seven volunteers, while a two-stage increase in potassium intake, by about 40% for eight days and a further 55% for 14 days, had no effect on the blood pressures of 21 volunteers. Renal electrolyte excretions and the blood pressures of all 28 subjects showed no statistically significant correlations between either sodium or potassium excretion and blood pressure. A weak negative correlation was found between the sodium: potassium ratio and systolic pressure. The small reductions in sodium intake and increases in potassium intake that might be achieved through propaganda and changes in food processing are unlikely to lower mean blood pressure in Western societies.