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Biomedical subjects

A Sebesteny

Publications and source records attributed to A Sebesteny.

At least 19 recordsLinked to original sources
PubMed1997

T cell receptor-alpha beta-deficient mice fail to develop colitis in the absence of a microbial environment.

Mice with null mutations in cytokine or T cell receptor (TCR) genes develop intestinal inflammation. In the case of interleukin-2-/- and interleukin-10-/- mice it has been demonstrated that normal intestinal bacterial flora can cause gut pathology. TCR-alpha-/- mice not only develop colitis but also produce a strong antibody response to self-antigens, such as double-stranded DNA. It is therefore important to establish whether the intestinal inflammation develops spontaneously or is induced by luminal antigens. To address this issue, a germ-free colony of TCR-alpha-/- mice was derived and compared with TCR-alpha-/- mice kept in conventional specific-pathogen-free conditions. Although specific-pathogen-free animals developed colitis with a high level of penetrance, there was no evidence of intestinal pathology in germ-free animals. Furthermore, intestinal inflammation was not seen in TCR-alpha-/- mice colonized with a limited bacterial flora consisting of Lactobacillus plantarum, Streptococcus faecalis, S. faecium, and/or Escherichia coli. We conclude that intestinal inflammation in TCR-alpha-/- mice does not occur spontaneously nor does it result from the presence of bacteria, per se, but rather it is initiated by a specific organism or group of organisms normally present in the gut flora that have yet to be identified.

Animals↗
PubMed1993

Experimental dermatophilosis in murine models of immunodeficiency.

Gnotobiotic mice with congenital immune deficiencies were infected with the skin pathogen Dermatophilus congolensis. Athymic (nude) mice with T cell deficiency were less susceptible than nude mice which also carried the beige mutation (beige-nude) with NK cell and granulocyte defects, as part of the murine equivalent of Chediak-Higashi syndrome. The additional presence of the x-linked immunodeficiency gene in other beige mutant mice, giving reduced B cell responsiveness, did not increase their susceptibility. BALB/c mice with the nude mutation and evidence of macrophage insufficiency, had a moderate level of susceptibility, greater than that of outbred nude mice but less than that of beige, nude mice. The appearance of the lesions on the haired mice was different from that on those with hairless skin (nude and beige-nude). On the haired mice thin crusts developed and healed rapidly, while on the hairless mice the lesions started as nodules and later progressed to crusts. The nude BALB/c mice developed atypical lesions, which resembled ulcers. Germ-free nude and beige-nude mice showed the same types and time course of infection as the gnotobiotic animals, suggesting that bacterial interference, by a limited skin flora, did not play a major role in defence against D. congolensis. However, bacteriological analysis indicated that D. congolensis could survive in the gut of germ-free mice. This work emphasizes the importance of non-specific immune mechanisms, such as epidermal hyperproliferation and the neutrophil, in resistance to D. congolensis.

Actinomycetales Infections↗
PubMed1992

Microbiologically monitored fumigation of a newly built SPF laboratory rodent facility.

The initial sanitization and sterilization of a newly built animal facility for the breeding and holding of specific pathogen free (SPF) rats and mice is described. The fumigation programme was started with methyl bromide treatment directed primarily against arthropods, followed by ammonia spray to kill coccidial oocysts and concluded by three formaldehyde treatments with fog and spray against bacteria and viruses. The practicalities and problems involved are described in detail and the rationale and purpose of the programme and its monitoring are discussed. The report is expected to contribute towards the establishment of a rational, efficient and standardized fumigation programme for SPF animal facilities, under increasing constraints of safety and environmental considerations concerning pollution with toxic and corrosive agents.

Animals↗
PubMed1985

Lipid keratopathy and atheromatosis in an SPF laboratory rabbit colony attributable to diet.

Sporadic cases of corneal opacity occurred in an SPF rabbit colony fed on a diet containing 10% white fish-meal. Routine histological monitoring also revealed atheromatous lesions involving the intima of the aorta, coronary arteries and the arteries of other organs in 29 rabbits examined. Serum cholesterol levels above 10 mmol/l were found in 7 rabbits, including 4 affected with corneal lesions, which proved to be lipid keratopathy on histochemical and electron microscopical examination. The serum cholesterol level was found to be within normal range (below 2.27 mmol/l) in 10 rabbits reared entirely on a modified version of the diet, where the 10% fish-meal content was replaced with 10% grass-meal. No more ocular or atheromatous lesions have been found since the adoption of the new diet for the colony.

Age Factors↗
PubMed1983

A paralytic disease in nude mice associated with polyoma virus infection.

Nude mice (nu/nu), heterotransplanted with human tumours and kept in isolators, were found to suffer from wasting and posterior paralysis. Electron microscopy of spinal cord tissue revealed virus particles in the oligodendrocytes consistent in size (35 to 40 nm), morphology and distribution with those of the polyoma--SV40 sub-group of papovaviruses. Serology and restriction enzyme analysis of the virus genome showed that the virus was the murine polyoma A2 strain. Inoculation of uninfected nude mice with 10(7) TCID50 of polyoma A2 strain virus produced a similar disease in these mice with wasting and, after 10 to 23 weeks, paralysis of the hind legs of all surviving mice. Extensive myelin disruption was seen throughout the brain stem and sacral region of the spinal cord and high titres of polyoma virus were found in the whole brain (10(8.8) TCID50/brain) and in the spinal cord (10(6.8) TCID50/spinal cord).

Animals↗
PubMed1980

Demyelination and wasting associated with polyomavirus infection in nude (nu/nu) mice.

Nude (nu/nu) mice bearing human tumour heterografts were affected with posterior paralysis and wasting. There was demyelination and infection of the oligodendrocytes of the spinal cord with a papovavirus. Similar virus particles and inclusion bodies were found in the bronchial epithelium, which showed histopathological changes. Similar changes were shown by the epithelia of the renal pelvis, ureter and choroid plexus. The virus was found in a transplantable human tumour, and evidence of spread by contact was also obtained. Intracerebral injection of spinal cord suspension from infected mice resulted in virus infected cutaneous carcinomata, demyelination with virus particles in the oligodendrocytes and posterior paralysis with wasting in adult nude mice. The suspension injected intraperitoneally into newborn Syrian hamsters produced tumours similar to those produced by murine polyoma. No evidence of infection was found in mice from the colony of origin. The virus was identified as murine polyoma Wild Type A2.

Animals↗
PubMed1979

Primary human breast carcinomas transplantable in the nude mouse.

Of 19 primary human breast carcinomas implanted into noninbred female nude mice, 3 produced transplantable tumors. Membrane components specific for human mammary epithelial cells were demonstrated in the cells from heterotransplants even after four or five passages in nude mice.

Animals↗
PubMed1978

The isolation of carbon dioxide-requiring (carboxyphillic) type 19 pneumococcus (Streptococcus pneumoniae) from diseased guinea-pigs.

Type 19 pneumococcus was isolated only in anaerobic cultures from tissue fluids of guinea-pigs suffering from exudative pericarditis and pleuropneumonia. The organism was pathogenic to mice even after 40 subcultures. Further study showed it to be carboxyphilic rather than anaerobic. The necessity of specifying various atmospheric conditions in the diagnostic bacteriological isolation routine is emphasized.

Animals↗
PubMed1976

Diseases of guinea-pigs.

Information on diseases of guinea-pigs is generally available in research institutes and breeding establishments. When dealing with an individual patient it is tempting to extrapolate from this pool of information, without realising that a number of factors can affect the disease situation in a colony which need not apply to the individual animal kept as a pet--or vice versa. Thus diseases may appear as an explosive outbreak in a group of cavies kept under uniform conditions while a single animal may be exposed to amateur management (Townsend 1975) and suffer in consequence. The diseases generally encountered in this species are dealt with here as they appear clinically.

Animals↗