Folate catabolites in spot urine as non-invasive biomarkers of folate status during habitual intake and folic acid supplementation.

Folate status, as reflected by red blood cell (RCF) and plasma folates (PF), is related to health and disease risk. Folate degradation products para-aminobenzoylglutamate (pABG) and para-acetamidobenzoylglutamate (apABG) in 24 hour urine have recently been shown to correlate with blood folate. Since blood sampling and collection of 24 hour urine are cumbersome, we investigated whether the determination of urinary folate catabolites in fasted spot urine is a suitable non-invasive biomarker for folate status in subjects before and during folic acid supplementation. Immediate effects of oral folic acid bolus intake on urinary folate catabolites were assessed in a short-term pre-study. In the main study we included 53 healthy men. Of these, 29 were selected for a 12 week folic acid supplementation (400 µg). Blood, 24 hour and spot urine were collected at baseline and after 6 and 12 weeks and PF, RCF, urinary apABG and pABG were determined. Intake of a 400 µg folic acid bolus resulted in immediate increase of urinary catabolites. In the main study pABG and apABG concentrations in spot urine correlated well with their excretion in 24 hour urine. In healthy men consuming habitual diet, pABG showed closer correlation with PF (rs = 0.676) and RCF (rs = 0.649) than apABG (rs = 0.264, ns and 0.543). Supplementation led to significantly increased folate in plasma and red cells as well as elevated urinary folate catabolites, while only pABG correlated significantly with PF (rs = 0.574) after 12 weeks. Quantification of folate catabolites in fasted spot urine seems suitable as a non-invasive alternative to blood or 24 hour urine analysis for evaluation of folate status in populations consuming habitual diet. In non-steady-state conditions (folic acid supplementation) correlations between folate marker (RCF, PF, urinary catabolites) decrease due to differing kinetics

Radiation induced CNS toxicity – molecular and cellular mechanisms

Radiotherapy of tumours proximal to normal CNS structures is limited by the sensitivity of the normal tissue. Prior to the development of prophylactic strategies or treatment protocols a detailed understanding of the mechanisms of radiation induced CNS toxicity is mandatory. Histological analysis of irradiated CNS specimens defines possible target structures prior to a delineation of cellular and molecular mechanisms. Several lesions can be distinguished: Demyelination, proliferative and degenerative glial reactions, endothelial cell loss and capillary occlusion. All changes are likely to result from complex alterations within several functional CNS compartments. Thus, a single mechanism responsible cannot be separated. At least four factors contribute to the development of CNS toxicity: (1) damage to vessel structures; (2) deletion of oligodendrocyte-2 astrocyte progenitors (O-2A) and mature oligodendrocytes; (3) deletion of neural stem cell populations in the hippocampus, cerebellum and cortex; (4) generalized alterations of cytokine expression. Several underlying cellular and molecular mechanisms involved in radiation induced CNS toxicity have been identified. The article reviews the currently available data on the cellular and molecular basis of radiation induced CNS side effects.   http://www.bjcancer.com © 2001 Cancer Research Campaig

Reference model for quality assurance of speech applications

The acceptance of speech applications is still very low in Germany. The German market of speech industry identified this problem and makes an effort to improve the quality of speech applications, which Should lead to higher user acceptance. To ensure higher quality standards, a reference model has been developed with special regard to the needs of interactive voice response systems (IVR). This model includes instructions to improve the process quality of the development process as well as methods, measurements and quality criteria to evaluate the product quality. Furthermore, the presented reference model differentiates between eight application types of IVR and describes which methods, measurements and quality criteria are especially important for each application type

Multimodale Nutzerschnittstellen-Gestaltung: Wie wirkt sich linguistische Informationsredundanz auf die Gebrauchstauglichkeit aus?

Die Kombination einer Sprach-Nutzerschnittstelle mit einer grafischen Nutzerschnittstelle, erlaubt eine Vielzahl von Darstellungsvarianten. Bisher gibt es wenige Gestaltungsrichtlinien, die auf empirischen Daten beruhen. Der vorliegende Beitrag beschäftigt sich mit der Auswirkung linguistischer Informationsredundanz auf die Gebrauchstauglichkeit einer Anwendung anhand von empirischen Ergebnissen. Es wurden drei mögliche Designvarianten als Prototyp implementiert und Nutzertests unterzogen. Auf deskriptiver Ebene führte ein mittlerer Redundanzgrad zu den besten Ergebnissen

Usability-Netzwerk. Ein Szenario für das Jahr 2002

This paper addresses the current situation of usability professionals in Germany. The results of two telephone interview studies give a first impression of the common usability practice in German web projects. Starting from these results, we present possible measures and current initiatives aiming at increasing the awareness for the significance of usability in industry and public. Furthermore, professional networks shall provide opportunities to share personal experiences and competences