Periarticular osteoporosis: a useful feature in the diagnosis of early rheumatoid arthritis? Reliability and validity in a cross-sectional diagnostic study using dual-energy X-ray absorptiometry.

Objectives: To identify regions of interest (ROIs) relevant to periarticular osteoporosis in RA with low precision error and sufficient inter-rater reliability and to test diagnostic validity for RA.

Methods: Periarticular BMD was measured using dual-energy X-ray absorptiometry (DXA). Five ROIs were defined around MCP and/or PIP joints II-V, II-IV and mid-metacarpal to mid-phalangeal.

Computerized cyclic voltammetric detection after HPLC of the antineoplastic agents etoposide, teniposide, adriamycin and its metabolite adriamycinol in urine samples.

A computerized electrochemical detection system for application after HPLC, provided with a cyclic voltammetric oxidative and reductive module, is described for the on-line qualitative determination of electroactive antineoplastic agents and metabolites in urine samples, collected from cancer patients, following intravenous administration.The application of two cyclic voltammetric detection modes provides an insight into both oxidative and reductive electrode reactions of compounds, passing the detector and the occurrence of (it)reversible chemical and electrochemical processes at the electrode surface. In this way, redox properties of drugs and metabolites characteristic of their molecular structure, can be established, which may provide information related to their (enzymatic) bioactivation.

Post-column coulometric generation and cyclic voltammetric identification of the free radical of the antineoplastic agent etoposide (VP 16-213).

It has been suggested that etoposide can be transformed 'in vivo' into a radical intermediate, which may be involved in the irreversible binding of etoposide to microsomal proteins and in DNA damage. To investigate some physico-chemical properties, the on-line coulometric production of this free radical and its subsequent cyclic voltammetric detection is described. For the synthesis, a coulometric ESA Coulochem 5100A module, equipped with an ESA 5010 analytical cell, has been used.

Improved HPLC-ECD analysis of mitomycin C, porfiromycin, VP 16-213 and VM 26 by implantation of software filters.

In high performance liquid chromatography with electrochemical detection (HPLC/ECD) much attention has been paid to the performance of the applied detection system with respect to reliability and sensitivity. In general, insufficient attention has been paid to relatively easy to implant devices for improved collection and handling of detection signals. Four models of software filtering are studied and compared with hardware filtering.

Pharmacokinetics of high-dose teniposide.

This paper describes the pharmacokinetics of teniposide (VM-26) after being administered iv in high doses to eight cancer patients (maximum dose, 1.0 g/m2). VM-26 levels in plasma, urine, saliva, duodenal fluid, and cerebrospinal fluid were determined using high-performance liquid chromatography in combination with electrochemical detection.