101-111
Analysis of fighting-associated wounds causing death of young male CD-1 mice in carcinogenicity studies
by Woo-Chan Son

Early death of CD-1 mice due to fighting-associated wounds was analysed using information gathered from the control groups of twenty mouse carcinogenicity studies, all deaths occurring within the first 50 weeks of the studies being reviewed. Of the 1453 mice in each sex, 101 (6.95 %) male and 69 (4.75%) female decedents with a statistical significance (p=0.016), in favour of females, were recorded during the first 50 weeks of study. The hazard ratio for gender was found to be 1.45. Analysis of factors contributing to death revealed that 26 (25.7%) males had integumentary wounds, 27 (26.7%), males exhibited neoplastic lesions, and 48 (47.5%) males had other changes. In females, the figures were 11 (15.9%), 28 (40.6%), and 30 (43.4%), respectively. A high proportion of the observed lesions such as ulceration, abscess-formation and granulomatous inflammation of the skin, subcutaneous tissues or muscle, were considered to be fighting-associated wounds. Of the neoplastic causes of death, haematopoietic tumours were the most common, followed by osteosarcoma, and some skin or mammary tumours. One of the most common nontumour factors contributing to death was kidney diseases (nephropathy and glomerulonephritis), followed by urinary obstruction of males. Some animals died from trauma/fracture, dosing accidents, unknown reasons or were also sacrificed due to poor clinical condition. From the mortality analysis of fighting-associated factors contributing to death, there was no significant statistical difference (p values, males=0.55, females=0.94) between single and multiple housed animals. In the hazard ratio analysis between single and multiple housing, multiple housed males have 1.32 times the risk of death when compared with single housed males, whereas this figure in females were found to be 1.05. In conclusion, housing density, especially in males, had an impact on survival; however, it could not be attributed solely to fighting-associated integumentary lesions.

113-127
Variability in patterns of intra-specific biting attack in commonly used genetic lines of laboratory mice
by Paul F. Brain & Sandra E. Hui (nee Jones)

Bite targets on opponents used by individually housed male, reproductively experienced male and lactating female subjects from outbred TO and Swiss Webster and inbred NZW/Ola, BALB/c, C57BL/10, DBA/2, CBA/Ca and C3H/He lines of mice were assessed. Ten-minute videotaped encounters with anosmic male TO or “congenic” opponents were used for this purpose. In general, the attacks shown by males appeared ‘ritualised’ with the head and ventral surface of the opponent being avoided. The lactating females showed no such inhibition. The intensity and incidence (and damaging nature of the attacks) was clearly influenced by strain of the resident, its sex, its reproductive experience and (in some cases) the nature of the opponent. This data may be helpful in controlling social stress in mouse studies.

143-149
Microsatellite analysis of mouse TNF and Cypla2 loci for polymorphism: detection and evaluation of genetic contamination
by Abdolhossein Rezaeian, Mohammad hossein Alimohammadian & Sirous Zeinali

The mouse TNF locus comprises tandemly arranged genes coding for Tnf alpha (cachectin) and Tnf ß (lymphotoxin). The mouse TNF and Cypla2 loci were selected to detect simple sequence length polymorphism on genomic DNAs of four laboratory mouse strains. These polymorphisms might be useful in the search for tumor supressor genes involved in specific cancers. The primary aim of this work was to analyse the use of these polymophic microsatellite markers, which could differentiate between four typical laboratory mouse strains (i.e. BALB/c, C57BL/6, CBA as three inbred mouse strains and Syrian Hamster as an outbred strain) and the second was to define possible genetic contamination of a BALB/c mouse colony. In this study, we investigated the applicability of DNA fingerprinting using short tandem repeats (STRs) by the use of PAGE and silver staining. We found that all microsatellite DNA sequences varied in size in the TNF locus in the four strains tested, but for the Cypla2 locus no polymorphism was found within these strains. To our knowledge this is the first report of lack of polymorphism in the Cypla2 locus within these strains. The other techniques for inbred mouse identification were skin grafting and a coat colour test. We found no signs of rejection during skin grafting within the BALB/c mouse strain and also as expected all strains showed normal phenotypes. These experiments suggested lack of genetic heterogeneity in Cypla2 locus and no evidence of genetic contamination was also found in the BALB/c mouse.

151-156
Three important endoparasites of laboratory woodchucks (Marmota monax) caught in the wild: Capillaria hepatica, Ackertia marmotae, and Taenia crassiceps
by Gero Hilken, Dietmar Büttner & Klaus Militzer

Wild animals kept in laboratories are potential carriers of viruses, bacteria and parasites. These might be a risk to people who have contact with those animals. We demonstrate this by the example of the American laboratory woodchuck (Marmota monax) which has been kept in our laboratory for 6 years (n=155). Beside Capillaria hepatica, the filaria Ackertia marmotae and the cestode Taenia crassiceps have been found. These three species were recognised outside the routine monitoring for parasites. As C. hepatica and T. crassiceps are human pathogens, the potential for transmission to humans and other woodchucks is estimated. Precautionary measures such as treatment to eradicate and hygiene instructions are discussed.

157-160
Development of laboratory animal science in Lithuania
by O. Ruksenas & V. Simkeviciene

The development of laboratory animal science (LAS) in Lithuania during the last decades is reviewed. Political changes in the 1990’s initiated development of LAS in Lithuania. Two aspects of LAS are analyzed – education and legislation. As regards education over 40 people possess FELASA category C certificates, a regular course on “Laboratory animal science” is delivered at Vilnius University, and a textbook “Basics of laboratory animal science” in Lithuanian has been published. Introduction of necessary legal Acts, establishment of the Lithuanian Ethics Committee on the use of laboratory animals under the State veterinary service, and the introduction of certification of experiments with vertebrate animals are the main results concerning legislation of laboratory animal science.