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Biomedical subjects

R Evers

Publications and source records attributed to R Evers.

54 records · Page 3Linked to original sources
PubMed1975

[A comparison of the radiation dose from film and xeroradiography (author's transl)].

Using a LiF dosimeter, comparative measurements were carried out on film mammography and xeromammography on surface and exit dose to the breast and scatter at the level of the gonads. Exit dose at 200 to 330 mR was approximately the same for both methods; incident dose at 6,800 mR for film mammography was significant higher than for xeromammography at 3,800 mR (Mo tube) or 1, 200 mR (tungsten tube). Scatter at the level of the gonads for all three methods was between 4.4 and 12.8 mR. For xeroradiography of the knee joint, the radiation dose of 466 mR was approximately three times that for a film technique (160 mR).

Humans↗
PubMed1975

[Xeroradiography of the neck and of the salivary glands (author's transl)].

This paper describes the possibilities of xeroradiography in the neck area. 6 clinical samples demonstrate the usefulness of this method in the diagnosis of different disorders of the neck organs. The advantage of xeroradiography is that in contrast to conventional x-ray technique all tissue densities are represented in a single image. The problems of the different radiation exposure are discussed.

Adenoma, Pleomorphic↗
PubMedDate not supplied

Microarray-based compendium of hepatic gene expression profiles for prototypical ADME gene-inducing compounds in rats and mice in vivo.

To examine species-specific aspects of the induction of absorption, distribution, metabolism and excretion (ADME)-related genes, we used 25 000 gene oligonucleotide microarrays to construct a rodent gene-response compendium that compared hepatic gene expression profiles and developed consensus aryl hydrocarbon receptor (AhR), constitutive androstane receptor (CAR) and pregnane X-receptor (PXR) ligand signatures relevant to drug clearance. Twenty-six inducer compounds were chosen from the literature. Rats and mice received one of six dose levels (log2 dose escalation, 32-fold dose range) of each compound daily for 3 days. Animals were necropsied 6-9 h after the last dose, and tissues were collected for RNA analysis. Hepatic gene expression profiles were obtained using Rosetta Resolver expression analysis system, and ADME-related genes were extracted. Cross-talk among nuclear receptors or hepatoxicity at high dose levels resulted in large signatures (usually >1000 genes at p < 0.01) for most compounds. After ADME gene transcript enrichment, agglomerative clustering separated AhR ligands from CAR/PXR ligands, but it was difficult to distinguish CAR from PXR ligands. Consensus signatures were derived from groups of AhR, CAR and PXR ligands; and cross-talk among responding genes was determined. Many compounds had distinct log dose-response profiles, and relative potencies for ligands were established. Robust responses by CYP1A1, CYP2B10 (CAR responsive in mice) and CYP2B15 (CAR responsive in rats) and CYP3A1 (PXR responsive in rats) were used to benchmark the relative potency of different ligands and to determine the relative selectivity for AhR, CAR or PXR. By using a compendium of gene expression profiles, we defined species-specific induction patterns across the ADME transcriptome.

Animals↗
PubMedDate not supplied

Expression profiles of 50 xenobiotic transporter genes in humans and pre-clinical species: a resource for investigations into drug disposition.

Carrier-mediated transporters play a critical role in xenobiotic disposition and transporter research is complicated by species differences and their selective tissue expression. The purpose of this study was to generate a comprehensive data set of xenobiotic transporter gene expression profiles in humans and the pre-clinical species mouse, rat, beagle dog and cynomolgus monkey. mRNA expression profiles of 50 genes from the ABC, SLC and SLCO transporter superfamilies were examined in 40 human tissues by microarray analyses. Transporter genes that were identified as enriched in the liver or kidney, or that were selected for their known roles in xenobiotic disposition, were then compared in 22 tissues across the five species. Finally, as clinical variability in drug response and adverse reactions may be the result of variability in transporter gene expression, variability in the expression of selected transporter genes in 75 human liver donors were examined and compared with the highly variable drug metabolizing enzyme CYP3A4.

Animals↗