1-5
The Use of Minipigs for Testing the Local Intranasal Toxicity of Fentanyl
by Lisbet Bønløkke Rankløve, Mette Marina Kaae Thorhauge, Christina S. Eriksen& Peter Glerup

The local intranasal toxicity of a nasal formulation of the opioid analgesic fentanyl was investigated in this study. Minipigs were used as the experimental model. Fentanyl was administered using the formulation and the device intended for human use. Doses of 400 μg fentanyl were administered 5 times daily to the minipigs for 4 weeks. In addition, the spreading pattern of the formulation in the minipig nasal cavity was investigated by applying a formulation containing methylene blue at necropsy.
Results: The methylene blue spread to the middle parts of the endoturbinates. The No-Observed-Adverse-Effect-Level (NOAEL) of intranasally administered fentanyl in minipigs was documented to be above 5 x 400 μg/day. After necropsy, no relevant treatment related macroscopic or microscopic findings were observed, but minimal focal deciliation/degradation of the respiratory epithelium was seen in one animal. In conclusion, intranasal administration of 400 μg fentanyl 5 times daily for a period of 4 weeks did not cause any treatment related changes in the nasal cavity of the minipig.

9-12
Non-human Primates in Biomedical Research
by J Hau & SJ Schapiro

Non-human primates remain essential for certain types of biomedical research.
Although non-human primates (NHP) account for less than a fraction of one percent of all of the animals used for biomedical research, their many similarities to humans make them vital, and presently irreplaceable, models for humans for certain types of research (Hau et al., 2000). The most common areas of research in which NHP are used include microbiology (including HIV/AIDS), neuroscience and biochemistry/ chemistry. Several of the Old World monkeys (Chlorocebus aethiops, Macaca mulatta, M. fascicularis and Papio spp.) are the most commonly used species for research (Carlsson et al., 2004). Based on all articles published in 2001, it has recently been estimated that the global number of NHP used in research, including those participating in more than one protocol, is in the vicinity of 100,000-200,000 animals annually (Carlsson et al., 2004). The authors of the present paper were invited to give evidence to the joint Academy of Medical Sciences/Medical Research Council/Royal Society/Wellcome Trust study into the use of non-human primates in research, and this article is therefore addressed to the joint committee.

17-30
Sampling Effects on Gene Expression Data from a Human Tumour Xenograft
by Berner JM, Müller CR, Holden M,Wang J, Hovig E and Myklebost O

Human tumour tissue transplanted to and passed through immunodeficient mice as xenografts make powerful model systems to study tumour biology, in particular to investigate the dynamics of treatment responses, e.g. to chemotherapeutic agents. Before embarking on large-scale gene expression analysis of chemotherapy response in human sarcoma xenografts, we investigated the reproducibility of expression patterns derived from such samples. We compared expression profiles from tumours from the same or different mice and of various sizes, as well as central and peripheral parts of the same tumours. Twenty-three microarray hybridisations were performed on cDNA arrays representing 13000 genes, using direct labelling of target cDNAs. An ANOVA-based linear mixed-effects model was constructed, and variances of experimental and biological factors contributing to variability were estimated. With our labelling procedure used, the effect of switching the dyes was pronounced compared to all other factors. We detected a small variation in gene expression between two tumours in the same mouse as well as between tumours from different mice. Furthermore, central or peripheral position in the tumour had only moderate influence on the variability of the expression profiles. The biological variability was comparable to experimental variability caused by labelling, confirming the importance of both biological and technical replicates. We further analysed the data by pair-wise Fisher’s linear discriminant method and identified genes that were significantly differentially expressed between samples taken from peripheral or central parts of the tumours. Finally, we evaluated the result of pooling biological samples to estimate the recommended number of arrays and hybridisations for microarray experiments in this model.

35-38
Two Intranasal Administration Techniques Give Two Different Pharmacokinetic Results
by Sveinbjörn Gizurarson, Erik Bechgaard and Rolf K. Hjortkjær

Minor changes in the administration technique used for intranasal instillation of clonazepam, have been found to influence the results significantly. A simple study was performed, where rabbits received 0.5 mg clonazepam intranasally. One group received the drug while fixed in a sitting position, where the other group was fixed in a supine position. The results show that both techniques where able to provide a rapid absorption with a tmax around 3-4 min. The Cmax and AUC, however, were very different. The Cmax was found to be 40 ng/ml and 86 ng/ml, respectively, and the AUC was found to be 891 and 2249 (ng/ml/min), respectively, for the sitting and the supine position. The relative bioavailability for sitting/supine was found to be 38%. These results show that the administration technique is very important and should not be underestimated.

43-44
Subcutaneous Versus Intraperitoneal Placement of Radiotelemetry Transmitters for Long-term Recording of Electroencephalography
by Kasper Larsen and Jesper Bastlund