Preparation and in vivo testing of porous alumina ceramics for cell carrier applications.

Microporous alumina was used to develop implantable cell carriers shaped as a hollow-sphere with a central opening to allow ingrowth of vascularised tissues. The carriers were produced by suspending the ceramic raw materials in water, homogenising and dropping the resulting slurry onto a heated plate (hot plate moulding, HPM). Morphological characteristics of the cell carriers were investigated by SEM and optical microscopy. Produced carriers had an average diameter of 4.9 mm. The material was highly porous (56 +/- 8%). For in vivo testing the cell carriers were implanted into abdominal wall of Zur: SIV rats for up to 50 weeks and investigated by light microscopy, SEM and TEM. The surface of the hollow carriers was in close contact with unirritated muscle tissue; no inflammation or capsule formation was observed. Loose connective tissue had grown into the hollow cell carrier, and after prolonged implantation >20 weeks adipocytes were observed. The absence of scar tissue formation around the implant and the vitality within the cavity of the hollow carriers indicate that porous alumina may be used for cell transplantation devices.

-Entrance of PCR for studying murine coronaviruses-. / Der Einsatz der PCR zum Studium muriner Coronaviren.

This paper describes a number of applications of the Polymerase Chain Reaction (PCR) in the study of enterotropic murine coronaviruses [mouse hepatitis virus (MHV)]. A diagnostic PCR was developed which detected all of 11 different MHV strains. This fast and reliable method was also able to differentiate MHV from other non-murine coronaviruses. On the basis of this assay a quantitative PCR was designed using a mutant template containing a point mutation which competed for the PCR primers. The amplification and cloning of the structural protein genes of enterotropic MHV strains it plasmid vectors for subsequent sequencing is described. In addition an RT PCR was developed which was able to selectivity detect artificially generated recombinant coronavirus.

Transmission of murine viruses and mycoplasma in laboratory mouse colonies with respect to housing conditions.

Pathogen-free sentinel mice were placed in 7 animal rooms with different housing conditions and were serologically screened for antibodies to mouse hepatitis virus (MHV), pneumonia virus of mice (PVM), Sendai virus, reovirus 3, Theiler's mouse encephalomyelitis virus (TMEV), ectromelia virus and Mycoplasma pulmonis by enzyme-linked immunosorbent assays, at intervals after introduction. The most commonly detected antibody was against MHV, which was found in mice from 4 rooms, followed by PVM antibody in mice from 3 rooms. Seroconversion to Sendai virus and TMEV was detected in mice from one room each. No seroconversion to any of the antigens was found in 2 rooms. The common criteria of these 2 rooms were that they housed pathogen-free animals from a single source and that the access to the rooms was, purposely or not, restricted to people who had no contact to other mice. The study demonstrated the importance of husbandry and hygienic regimen on the prevalence of infectious agents in laboratory mice.

Two-dimensional DNA-fingerprinting in animals.

DNA-fingerprinting has become, during the last five years, an important method of genetic analysis in medicine, veterinary medicine and other disciplines. The power of this technique, especially for genetic linkage analysis, may be enhanced in humans by using the two dimensional DNA-fingerprinting method. Here we show that this procedure can successfully be applied to different animal species, e.g. pig, dog and mouse. Optimal conditions, however, have to be determined for each species tested. With the use of marker systems as well as computer programs it will be possible to evaluate complex two-dimensional spot patterns in a short time and with high reliability.

[DNA diagnosis in veterinary medicine: I. DNA fingerprinting]. / DNA Diagnostik in der Tiermedizin: I. DNA Fingerprinting.

With the development of recombinant DNA-technology during the last 15 years, it became possible to analyse genetic variability directly at the level of genomic DNA. Restriction-Fragment-Length-Polymorphism (RFLP) and Highly-Variable-Regions (HVRs) lead to the development of new genetic markers, which can be used for the localization of normal and mutated genes. Some polymorphisms are hypervariable and can therefore be applied to carry out DNA-fingerprints thus identifying individuals from man and animals.

Clioquinol toxicity in the dog.

A number of instances have been reported in the scientific literature in which acute intoxication with halogenated oxyquinolines has led in some species to convlusions, often followed by death. The toxicity of repeated doses of clioquinol has been investigated extensively in the dog. The clinical syndrome induced in this species is characterized by anorexia, weight loss, extremem muscle weakness and emaciation. In some animals surviving this impairment of condition for several weeks, neuropathy of the central nervous system, but not of the peripheral nerves ensued. It is suggested that these toxicological manifestations are less dependent on the dose-level than on the degree of absorption. Some suggestions regarding the aetiology of the lesions are made.