The solubilities of synthetic calcium hydroxyapatites [Ca(OH)A], Ca5(P04)30H, are determined in the ternary system Ca(OH)2+H3P04+H20 at 25°C in the pH range 5-7 by equilibration with dilute &PO4 solutions. The thermodynamic solubility product Ksp of precipitated Ca(OM)A, prepared by titrating a boiling aqueous suspension of Ca(OH), with M3P04, is (3.2s k 0.29) x 11101~ dm-27 . Ca(OH)A.prepared by solid state reaction of CaC03 and CaHP04 and precipitated Ca(0H)A heated at high temperatures in a water vapour atmosphere showed no constant Ksp. After being washed, these samples equilibrate according to the usual solubility product principles with a Ksp value of (3.d4+0&) xThe influence of heat treatment and washing on the solubility behaviour is discussed. Deviations from solubility behaviour which accords with the usual solubility product principles are caused by reactions occurring at the surface of the solid. The latter are induced by a high free energy of the solid and/or the presence of a fraction with high solubility associated with the Ca(0H)A sample. and (2. 6, -, k0.21) x mo19 dm-27, respectively. MATERIALSCa(0H)A samples were prepared by precipitation or by solid state reaction.

We have developed a new protein microarray (ImmunoFlow Protein Platform, IFPP) that utilizes a porous nitrocellulose (NC) membrane with printed spots of capture probes. The sample is pumped actively through the NC membrane, to enhance binding efficiency and introduce stringency. Compared to protein microarrays assayed with the conventional incubation-shaking method the rate of binding is enhanced on the IFPP by at least a factor of 10, so that the total assay time can be reduced drastically without compromising sensitivity. Similarly, the sensitivity can be improved. We demonstrate the detection of 1 pM of C-reactive protein (CRP) in 70 microL of plasma within a total assay time of 7 min. The small sample and reagent volumes, combined with the speed of the assay, make our IFPP also well-suited for a point-of-care/near-patient setting. The potential clinical application of the IFPP is demonstrated by validating CRP detection both in human plasma and serum samples against standard clinical laboratory methods.

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A rat model was developed to test the watertightness of sutures and used to evaluate the value of fibrin glue (Tissucol®, Immuno France, Tisseel®, Immuno U.S., Inc.) in making conventional sutures watertight. Fibrin glue raised the mean hydrostatic pressure to which the skin suture resisted from 9.1 to 26.3 cm H(2)O, thus indicating that it enhances suture watertightness immediately after surgery. After 3 and 6 days, the pressure was increased, respectively, from 24.8 to 47.9 and from 56.5 to 73.3 cm H(2)O. For bladder sutures, the results are comparable.