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Biomedical subjects

I Kunstýr

Publications and source records attributed to I Kunstýr.

At least 19 recordsLinked to original sources

Polymerase chain reaction for detection of guinea pig adenovirus.

Lack of in vitro cultivation methods has inhibited the development of rapid, reliable diagnostic procedures for adenovirus-associated necrotizing bronchopneumonia in guinea pigs. Because polymerase chain reaction (PCR) techniques are well established for human adenoviruses, primers for the amplification of guinea pig adenovirus DNA were evaluated. The DNA for PCR was purified from the lung tissue of spontaneously infected and healthy guinea pigs. Adenovirus DNA could only be detected in the lungs of the infected animals. Subsequent sequence analysis of PCR products revealed that the guinea pig adenovirus is a distinct adenovirus.

Adenoviridae↗

Fungus Paecilomyces: a new agent in laboratory animals.

The fungus Paecilomyces has not yet been considered a health problem in laboratory animals. However, this agent known as a 'spoiler' of fruit beverages and other foodstuffs is an opportunistic pathogen especially in immunocompromised humans. Since 1985, we have isolated Paecilomyces, most probably P. variotti, from six laboratory animal species, mainly rats. In about 90% of cases the organism was localized in the respiratory tract and there are some other findings favouring the hypothesis of an airborne infection. During this long observation period no consequences for the health of rats in one closed 'infected' SPF breeding unit (A) could be observed. In a controlled histological study on five infected rats, no lesions attributable to this mycotic agent could be detected. However, a self-limiting spontaneous outbreak of papular skin lesions associated with Paecilomyces was observed in a breeding colony (F) of hairless mice. The role of this fungus in an acute outbreak of respiratory signs in another colony of conventional rats (B) was considered to be secondary. Bearing in mind its occasionally harmful role in humans, relatively high resistance to disinfectants and toxigenicity, this new agent should be monitored and considered a potential health risk for laboratory animals.

Animals↗

Granulomatous dermatitis and mastitis in two SPF rats associated with a slowly growing Staphylococcus aureus--a case report.

An isolated occurrence of multifocal severe granulomatous dermatitis and mastitis accompanied by extensive calcifications is described in 2 female Sprague-Dawley, SPF breeding rats. Poorly growing Staphylococcus aureus of uncertain lysotype (probably lysotype II) was isolated from the lesions of both rats. The source of infection could not be determined. No further cases in the closed barrier maintained breeding colony occurred in the following 7 months. Difficulties in interpreting these findings and the practical consequences relating to the hygienic status of the barrier breeding colony are discussed.

Animals↗

Inefficacy of enrofloxacin in the elimination of Pasteurella multocida in rabbits.

The administration of enrofloxacin (5 mg/kg subcutaneously every 12 h for 10 days) failed to eliminate Pasteurella multocida from all naturally and experimentally infected rabbits. Although the enrofloxacin concentrations in serum and in turbinate bones were greater than the determined minimal inhibitory concentrations, P. multocida could be detected in nasal cavities, turbinates, trachea, middle ear and outer ear of experimentally infected rabbits after treatment. It is to be supposed that P. multocida colonizes organs or tissues in which an effective enrofloxacin concentration cannot be achieved. Such sites could be the paranasal sinuses, the auditory tube and the middle ear. This finding underlines the indispensibility of in vivo testing of antibiotic effectiveness.

Animals↗

Characterization of two Metabacterium sp. from the gut of rodents. 1. Morphology and histochemical examination of a new Metabacterium sp. from the gut of the European hamster (Cricetus cricetus)

A new giant Gram-negative non-cultivatable symbiotic endospore-forming bacterium was found in the gut of the European hamster. This "Metabacterium" sp., provisionally named "Metabacterium criceti", sp. n., has a length of approximately 20 microns and thickness of 4 microns. It forms 1 to 2 cylindrical endospores, approximately 9 microns long and 1.4 microns thick. TEM-micrographs show a cell wall structure characteristic of Gram-negative bacteria. Vegetative cells are filled with granules 0.3 micron in diameter which resemble starch granules. The reproduction occurs with binary fission and by formation of two endospores. Of thirteen biochemical components sought, four, i.e. glycogen, triacylglycerols, peroxidase and alkaline phosphatase, were not found. Starch, acid mucosubstances, DNA, RNA, lipids, proteins, adenosine triphosphatase and acid phosphatase were found in different patterns, depending on the developmental stage of the bacterium. In the vegetative cell stage all these components, with the exception of starch, were found. In the endospore-bearing cell stage, only the starch-like cell component granules could be detected. In free endospores only DNA, RNA and acid phosphatase were found. Some of the components, i.e. DNA, lipids, starch-like granules, were linked to certain cell substructures, the distribution of others, viz. polysaccharides, RNA, adenosine triphosphatase and proteins was diffuse. The lipids, found only in vegetative cells, were associated with the cell wall.

Animals↗

Characterization of two "Metabacterium" sp. from the gut of rodents. 2. Heteroxenic cultivation and proof of dipicolinic acid in "M. polyspora".

The vegetative cell of "Metabacterium polyspora" is "cucumber-shaped", about 21 x 5.7 microns, Gram-negative. Cylindrical endospores are best stained by Rakette and Ziehl-Neelsen staining. The bacterium reproduces by sporulation (2 to 8 endospores per cell) and by binary fission. Lateral, bow-like "hatching" of the endospores was seen. About 52% of guinea pigs harbor 5 x 10(6), 36% below 2 x 10(6) and 1% more than 1 x 10(8) "M. polyspora" in 1 g of caecal content. Dipicolinic acid was demonstrated using HPLC in the caecum homogenate from a guinea pig. The amount of it was proportional to the number of spores. Cultivation under strict anaerobic conditions did not succeed. It was possible to cultivate this giant endosymbiont in vitro in a heteroxenic culture incubated in a 5% CO2 atmosphere using liquid medium supplemented with cell-free filtrate of the caecum. The caecum filtrate containing undefined growth factor(s) is necessary for long-term culture. The replication rate was low. These findings suggest that the giant endosymbiont "M. polyspora" is a spore-forming prokaryote without the attributes of a strict anaerobe.

Animals↗

Host specificity of cloned Spironucleus sp. originating from the European hamster.

In vivo experiments with a clone of the intestinal flagellate Spironucleus sp. originating from the laboratory European hamster (Cricetus cricetus), and the comparison with a spontaneous infection from laboratory bred European hamsters suggest high specificity of this clone for the homologous host. Only the Syrian golden hamster (Mesocricetus auratus) could be infected experimentally, though the mean intensity of infection was lower. Other heterologous recipients, mice and rats of one outbred and one inbred strain each, could not be infected. Even immunodeficient mice (athymic and C.B-17-scid) remained uninfected after inoculation of 5 x 10(5) cysts per mouse. This is the second Spironucleus clone, after the rat isolate (Schagemann et al., 1990), with a high level of host specificity suggesting heterogeneity within the genus Spironucleus.

Animals↗

[Laboratory animals--suggestions, views, warnings].

Basic informations are given on the Central Laboratory Animal Facility at the Hannover Medical School, Lower Saxony, which served as a model for similar facilities in nearly all medical schools in former West-Germany. Centralized facilities for laboratory animals as a service for bio-medical research are meanwhile common and well established in all universities of western countries. The lack of money is, certainly the paramount limiting factor hampering a soon realization of similar central facilities at czech and slovak medical schools. Another serious obstacle which could soon emerge comes from the psychologic-ethical area. It is the emotional and unreasonable shift in the society's consciousness in western countries pertaining the use of animals for research which si promoted and perpetuated by plenty of legal and illegal actions of many potent organizations of so called animal rightists or activists or antivivisectionists. Such organizations do not yet exist in Czechoslovakia but the situation can change abruptly. The second part of this article consists in the description of the roots of such organizations and the description of their activities in the western countries in order to develop successful contra-strategies.

Animal Testing Alternatives↗

Host specificity of Giardia muris isolates from mouse and golden hamster.

One isolate of Giardia muris from a naturally infected laboratory mouse (Mus musculus) and one from a naturally infected golden hamster (Mesocricetus auratus) were passaged three times by the inoculation of ten cysts (the minimal infectious dose) into barrier-maintained homologous hosts. Both of the resultant isolates were tested for infectivity by intragastric inoculation of 3-5 x 10(5) cysts into 40 mice (2 inbred strains), 40 rats (2 inbred strains), and 19 golden hamsters (1 outbred strain). Rats were not susceptible to infection with either isolate. Mice and golden hamsters did develop infections following their inoculation with the heterologous isolates. The mean intensity of heterologous infections with the hamster isolates was significantly lower than that of homologous infections. The mouse isolate induced a higher mean intensity of infection in hamsters as compared with homologous recipients. The mean intensity of infections induced by both isolates was greater in male hamsters than in females.

Animals↗

Streptococcus canis arthritis in a cat breeding colony.

This is the first description of a pathologic condition--arthritis in cats affecting mainly one joint, i.e. monarthritis--caused by Streptococcus canis (S. canis), of the Lancefield serologic group G. Six cases were recorded in a closed cat breeding colony during a 6 month period in 1988, and one additional case in 1990. Therapy with penicillin and streptomycin led to full recovery in four of six cases. The bacterium had been detected from different purulent processes sporadically--including one case of purulent arthritis in 1982--as a nosocomial infection since 1980, the year the breeding colony was established. A possible genetic predisposition (high inbreeding) may have contributed to the accumulation of the six cases in 1988. Although S. canis was isolated in mouse, rat, rabbit and dog, cat and man seem to be more frequently affected. There are some similarities between S. canis-arthritis in cat and man.

Animals↗

Host specificity of cloned Spironucleus muris in laboratory rodents.

With three clones of Spironucleus muris (S. muris)--established from a mouse, hamster, and rat--homologous and heterologous host species were experimentally infected. Each host was susceptible to the clone originating from the homologous donor. In addition, both mice and hamsters were susceptible to the reciprocal heterologous clones. In contrast, infections of the rat with both heterologous clones were very poor, i.e. quantitatively low and ephemeral. It was not possible to infect hamsters and mice, not even athymic, with S. muris from the rat. This suggests a strain heterogeneity within the genus S. muris. In general, the genetic background of the host influenced the infection, the sex of the host did not.

Animals↗

Characterization of some previously unclassified Pasteurellaceae isolated from hamsters.

Bacteria isolated from purulent processes on the jaws of European hamsters (Cricetus cricetus) and from intestinal inflammatory processes in Syrian hamsters (Mesocricetus auratus), bred as laboratory animals have been shown to be phenotypically similar but not identical with Pasteurella pneumotropica. Deoxyribonucleic acid (DNA)-DNA hybridization studies indicate that with one exception, the strains represent two new species of the family Pasteurellaceae. In the absence of a close genomic relatedness to members of the genera Actinobacillus or Pasteurella or allied organisms, however, the two new taxa are described without any formal designation. The one exception was identified as Actinobacillus capsulatus, a species not previously isolated from hamsters.

Actinobacillus↗

Humoral antibody response of rabbits to experimental infection with Encephalitozoon cuniculi.

Six female rabbits (Oryctolagus cuniculus) were experimentally infected intravenously with approximately 1.5 X 10(7) live spores of Encephalitozoon cuniculi. Head tilt was observed as the single clinical sign in only one of the six animals. Antibody response was registered over 68 days postinfection using the indirect immunofluorescence test (IFT) for IgM and IgG, and the carbon immunoassay (CIA). IgG titers reached a level of 160-2560 after a latent phase of 13-28 days, followed by a 2-4 week relatively steep increase. The IgM seroconversion was faster than that of IgG and occurred at the beginning of the antibody response. Thus, simultaneous detection of both IgM and IgG allowed the infection to be identified as recent. Long, short, and episodic antibody responses could be distinguished: the IgG titer continued to increase on Day 68 in one animal (long response) and began to decrease between Days 45 and 63 in three other animals (short response). In two additional animals the seroconversion was very short, occurring between Days 13 and 41, and 28 and 52, respectively (episodic response). The CIA proved to be specific, reliable, and simple to perform; titers were slightly higher than in the IFT. Parasite pseudocysts were detected scattered throughout the brain on Day 68 in four of the six rabbits. The persistence of antigen in the brain did not correlate with antibody response, which in most cases was shorter.

Animals↗

Paresis of peristalsis and ileus lead to death in lactating mice.

Based on the examination of 45 dead and 5 moribund female mice during a 2-year period, we are able to describe a new disease entity: ileus of the small intestine in lactating mice caused by a paresis of peristalsis. Diarrhoea was not observed and inflammation and infectious agents were not found. Females were affected during the 2nd week of their first lactation. The condition may have a mortality rate as high as 40%. It is assumed that exhaustion (calcium, glucose, etc.) is the cause of this condition. Consequently, the development of a dietary supplement or of a special diet for lactating mice may prove beneficial in preventing this disease. Endogenic (Clostridia) or exogenic toxic components may also play a role.

Animals↗