Modification of a continuous flow method for analysis of trace amounts of nitrate in iron-rich sediment pore-waters of mine pit lakes.

Nitrate was analysed in pore-waters with high ionic strength. Extremely high concentrations of dissolved ferrous iron interfere common analytical methods. The automatic photometrical procedure based on the cadmium reduction method is often used for analysis of nitrate in water samples (continuous flow analysis CFA). An integrated dialysis usually serves for sample dilution and (or) sample purification (from particles). Iron was precipitated as iron hydroxide due to the imidazole buffer system (pH 7.5). The dialysis membrane is an effective barrier for iron hydroxide particles to prevent interferences within the cadmium column or the flow-cell. However, dialysis membrane is blocked successively after analysis of several iron-rich pore-water samples by agglomeration of precipitated iron. The blocking of nitrate diffusion through the dialysis membrane is tantamount to a decrease of analytical sensitivity to recognise by decreasing photometrical extinction. Minimising the iron deposition within the dialyser solved the problem. A simple modification of the CFA apparatus was found to keep the analytical sensitivity nearly constant: The mixing coil for the imidazole buffer was considerably elongated. Nearly all iron hydroxide was deposited at the glass coil surface installed before the dialyser. At least 50 iron-rich samples could be analysed within one sample queue with a loss of sensitivity <10%. The recovery of nitrate was about 95%, demonstrated by spiking experiments.

A cellulose-binding domain-fused recombinant human T cell connective tissue-activating peptide-III manifests heparanase activity.

The chemokine connective tissue-activating peptide (CTAP)-III, which belongs to the leukocyte-derived growth factor family of mediators, was previously shown to be mitogenic for fibroblasts. However, it has recently been shown that CTAP-III, released from platelets, can act like a heparanase enzyme and degrade heparan sulfate. This suggests that CTAP-III may also function as a proinflammatory mediator. We have successfully cloned CTAP-III from a lambdagt11 cDNA library of PHA-activated human CD4(+) T cells and produced recombinant CTAP-III as a fusion protein with a cellulose-binding domain moiety. This recombinant CTAP-III exhibited heparanase activity and released degradation products from metabolically labeled, naturally produced extracellular matrix. We have also developed polyclonal and monoclonal antibodies, and these antibodies against the recombinant CTAP-III detected the CTAP-III molecule in human T cells, polymorphonuclear leukocytes, and placental extracts. Thus, our study provides tools to examine further immune cell behavior in inflamed sites rich with extracellular moieties and proinflammatory mediators.

Peripheral arteriovenous anastomosis: an alternative technique in a free flap transfer.

Prevention of thrombosis in the inflow and outflow vessels of a free flap is a problem of current interest. The method of creating a peripheral arteriovenous anastomosis within a free flap was validated in an experimental study and substantiated in a clinical case. No thrombotic complications were observed in 16 transfers of saphenous fasciocutaneous flaps in a dog model, as well as in an elderly patient with free radial forearm flap transfer to an irradiated foot. Scanning electron microscopy of the venous anastomosis proximal to the arteriovenous fistula revealed the difference of pathologic changes as early as 4 hr following surgery. It is the conclusion of the authors, that performing a distal arteriovenous fistula in a free flap, is an effective procedure for prevention of early occlusion in a proximally anastomosed artery and vein.