The current studies were intended to determine whether the anabolic effects of calcitonin (CT) on human osteoblast-line cells were (1) unique to osteosarcoma cells or also evident in osteoblast-line cells derived from normal human bone; and/or (2) associated with effects on several insulin-like growth factor (IGF) system components. Preliminary studies identified several osteoblastic cell lines, derived from normal human bone, which showed calcitonindependent increases in cell proliferation, alkaline phosphatase activity, and/or (45)Ca uptake (P < 0.05-P < 0.001). Two of these cell lines-(human vertebrae) HBV-155 and HBV-163-were included with the human osteosarcoma cell line, SaOS-2, in most of our subsequent studies of calcitonin effects on selected IGF system components: IGF-II, IGF-I, and IGF binding proteins -3, -4, and -5. The results of those studies revealed that a 48 hour exposure to salmon CT caused a dose-dependent (0.03-3 mU/ml) increase in the net extracellular level of IGF-II (r = 0.96, P < 0.01) in serum-free cultures of SaOS-2 cells, with a maximal 60% increase at the highest tested dose (P < 0.02). Similar effects were seen with HBV-163 cells (r = 0.90, P < 0.01) and HBV-155 cells (r = 0.55, P < 0.02). The effect of calcitonin on the extracellular level of IGF-II was biphasic with respect to time: it decreased at 6 hours (P < 0.005 and P < 0.001, for SaOS-2 cells and HBV-163 cells, respectively) and increased at 24 hours (P < 0.02 and P < 0.05). These calcitonin-dependent increases in the extracellular level of IGF-II were associated with parallel increases in IGF-I (P < 0.005 for SaOS-2 cells and P < 0.03 for HBV-163 cells), but calcitonin did not affect the extracellular level of transforming growth factor (TGF)-beta. The calcitonin-dependent changes in IGF-II were not associated with changes in the extracellular levels of IGF binding proteins -3, -4, or -5. Finally, our studies showed that two other members of the CT superfamily-CT gene-related peptide and amylin-did not mimic the effect of CT to increase the extracellular level of IGF-II. Together, these data demonstrate that human osteoblast-line cells derived from normal human bone can respond to CT, and that those responses can include CT dose- and time-dependent increases in the extracellular levels of IGF-I and IGF-II.

Removal of copper ion (Cu2+) by using surfactant modified laterite (SML) was investigated in the present study. Characterizations of laterite were examined by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), inductively coupled plasma mass spectrometry (ICP-MS), and total carbon analysis. The optimum conditions for removal of Cu2+ by adsorption using SML were systematically studied and found as pH 6, contact time 90 min, adsorbent dosage 5 mg/mL, and ionic strength 10 mM NaCl. The equilibrium concentration of copper ions was measured by flame atomic absorption spectrometry (F-AAS). Surface modification of laterite by anionic surfactant sodium dodecyl sulfate (SDS) induced a significant increase of the removal efficiency of Cu2+. The surface modifications of laterite by preadsorption of SDS and sequential adsorption of Cu2+ were also evaluated by XRD and FT-IR. The adsorption of Cu2+ onto SML increases with increasing NaCl concentration from 1 to 10 mM, but at high salt concentration this trend is reversed because desorption of SDS from laterite surface was enhanced by increasing salt concentration. Experimental results of Cu2+/SML adsorption isotherms at different ionic strengths can be represented well by a two-step adsorption model. Based on adsorption isotherms, surface charge effects, and surface modification, we suggest that the adsorption mechanism of Cu2+ onto SML was induced by electrostatic attraction between Cu2+ and the negatively charged SML surface and nonelectrostatic interactions between Cu2+ and organic substances in the laterite.

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