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Biomedical subjects

C Leutenegger

Publications and source records attributed to C Leutenegger.

8 recordsLinked to original sources
PubMed2003

Inflammation and changes in cytokine levels in neurological feline infectious peritonitis.

Feline infectious peritonitis (FIP) is a progressive, fatal, predominantly Arthus-type immune-mediated disease that is triggered when cats are infected with a mutant enteric coronavirus. The disease presents variably with multiple organ failure, seizures, generalized effusion, or shock. Neurological FIP is clinically and pathologically more homogeneous than systemic 'wet' or 'dry' FIP; thus, comparison of cytokine profiles from cats with neurological FIP, wet FIP, and non-FIP neurological disease may provide insight into some baseline characteristics relating to the immunopathogenesis of neurological FIP. This study characterizes inflammation and changes in cytokines in the brain tissue of FIP-affected cats. Cellular infiltrates in cats with FIP included lymphocytes, plasma cells, neutrophils, macrophages, and eosinophils. IL-1 beta, IL-6, IL-12, IL-18, TNF-alpha, macrophage inhibitory protein (MIP)-1 alpha, and RANTES showed no upregulation in the brains of control cats, moderate upregulation in neurological FIP cats, and very high upregulation in generalized FIP cats. Transcription of IFN-gamma appeared upregulated in cats with systemic FIP and slightly downregulated in neurological FIP. In most cytokines tested, variance was extremely high in generalized FIP and much less in neurological FIP. Principal components analysis was performed in order to find the least number of 'components' that would summarize the cytokine profiles in cats with neurological FIP. A large component of the variance (91.7%) was accounted for by levels of IL-6, MIP-1 alpha, and RANTES. These findings provide new insight into the immunopathogenesis of FIP and suggest targets for immune therapy of this disease.

Animals↗
PubMed2001

Upregulation of mRNA of interleukin-1 and -6 in subchondral cystic lesions of four horses.

This study investigated the potential association of interleukin-1beta (IL-1beta) and interleukin-6 (IL-6) in subchondral cystic lesions (SCL) in horses. With the technique of in situ hybridisation in paraffin sections of fibrous tissue of SCL and quantitative real-time PCR in fresh frozen fibrous tissue and undecalcified bone sections of SCL embedded in acrylic resin, upregulation of mRNA of both cytokines could be demonstrated. mRNA of IL-1beta was upregulated at the periphery of the cystic lesion adjacent to normal bone, whereas IL-6 mRNA was upregulated within the fibrous tissue found within the centre of the SCL. It was concluded that both cytokines are associated in pathological bone resorption observed in SCL and, in combination with increased production of prostaglandin E2, may be responsible for the slow healing, maintenance or further expansion of the cystic lesions.

Animals↗
PubMed2000

Spontaneous production of nitric oxide (NO), prostaglandin (PGE2) and neutral metalloproteinases (NMPs) in media of explant cultures of equine synovial membrane and articular cartilage from normal and osteoarthritic joints.

Nitric oxide (NO), prostaglandin E2 (PGE2), and the activity of neutral metalloproteinases (NMPs) were measured in conditioned media of equine synovial membrane and articular cartilage explant cultures from horses with normal joints (n = 7) and from horses affected with moderate (n = 7) or severe osteoarthritis (n = 14) as judged by macroscopic appearance. Normal articular cartilage appeared glossy and bluish-white, was of normal thickness and showed no evidence of discolouration, fibrillation or other cartilage discontinuity. Slight discolouration and fibrillation or minor clefts of the cartilage were considered as moderate OA, whereas erosions of articular cartilage down to the subchondral bone were considered as cases of severe OA. Explant cultures of equine synovial membrane and articular cartilage released the local mediators, NO and PGE2, as well as detectable levels of NMP activity into culture media. Concentrations of NO were higher in articular cartilage explants compared to synovial membrane explants, whereas concentrations of PGE2 were higher in synovial membrane explants. The NMPs with collagenolytic activities were similar in both explant cultures, whereas gelatinolytic activities were higher in synovial membrane explant cultures and caseinolytic activities were generally higher in articular cartilage explant cultures. Furthermore it was shown that concentrations or enzyme activities increased according to the severity of disease of the joints. Concentrations for NO, collagenolytic and gelatinolytic NMPs were relatively stable, whereas PGE2 and caseinolytic NMP concentrations increased over time in culture.

Animals↗
PubMed1999

The role of polymerase chain reaction and its newer developments in feline medicine.

We give a brief overview on the principles of the polymerase chain reaction (PCR), reverse transcriptase PCR (RT-PCR), quantitative competitive PCR and real-time PCR (TaqMan technology). The literature dealing with PCR and its role in the diagnosis, pathogenesis and research of infectious diseases of the domestic cat is reviewed. Cross-contaminations which occasionally occur during handling of amplified DNA may be an important problem in the PCR laboratory. In many infectious diseases, PCR results are difficult to interpret as their predictive positive and negative values are not always known. Newer assays, such as TaqMan procedures, are becoming increasingly reliable and cost-effective. It can be expected that additional knowledge on how to interpret PCR results will soon be available.

Animals↗
PubMed1996

[Liberation into the wild of wild felines--danger of the release of virus infections].

There are several felidae amongst the numerous endangered species. Means of aiding survival are the reintroduction to the wild of animals bred under the auspices of man and their relocation from densely populated to thinly populated areas. It is unlikely that the dangers of such reintroduction or relocation projects have been examined sufficiently in respect to the risks of virus infections confronting individuals kept in zoos or similar situations. This report presents three examples to illustrate that accidental virus infections may be expected to occur when relocating and reintroducing wild cats. The first example is the reintroduction of captive snow leopards. Zoo bred snow leopards may be infected with FIV, a virus infection that is highly unlikely to occur in the original himalayan highlands of Tibet and China. A second example is of several cases of FIP that occurred in European wild cats bred in groups in captivity. The third example mentioned is the relocation of lions from East Africa where all the commonly known feline viruses are wide-spread to the Etosha National Park. In the latter, virus infections such as FIV, FCV and FPV do not occur. The indiscriminate relocation and reintroduction of the wild cats mentioned here harbours a potential of undesirable consequences.

Animals↗
PubMedDate not supplied

Fibrous tissue of subchondral cystic lesions in horses produce local mediators and neutral metalloproteinases and cause bone resorption in vitro.

OBJECTIVES: To define the release of nitric oxide (NO), prostaglandin E2 (PGE2), and the neutral metalloproteinases (NMPs) in horses with subchondral cystic lesions (SCL) and to study bone resorption triggered by conditioned media of fibrous tissue of SCL in vitro. STUDY DESIGN: Equine explant cultures of fibrous tissue of SCL, and synovial membrane and articular cartilage of normal horses and horses affected with moderate and severe osteoarthritis were performed. NO, PGE2, and NMP concentrations of media samples were measured, and osteoclast formation and activation was studied in vitro. ANIMALS: Experiment 1: 32 horses with SCL (n = 8), normal joints (7), and joints with moderate (7) and severe (10) osteoarthritis (OA). Experiment 2: 22 horses with SCL (n = 3), normal joints (7), and chip fractures (12). Experiment 3: Conditioned media of fibrous tissue from 3 horses with SCL of the medial femoral condyle (n = 1), distal metacarpal bone (1), and tarsal bone (1). METHODS: Determinations of local mediator concentrations were made with the Griess assay for NO and an enzyme immunoassay kit for PGE2 concentrations in biological fluids. Enzyme activities were assessed with radiolabeled substrates indicating collagenolytic, gelatinolytic, and caseinolytic activities. The resorption pit assay was used to assess osteoclast recruitment and activity. RESULTS: Fibrous tissue of SCL produced NO, PGE2, and NMPs. Of all the variables measured, PGE2 concentrations were the highest in cystic tissue of SCL compared with synovial membrane and articular cartilage from normal joints and joints with chip fractures, indicating that this mediator may play an important role in pathological bone resorption associated with SCL. These findings were supported by the observation that conditioned media of SCL tissue were capable of recruiting osteoclasts and increasing their activity. CONCLUSION: Fibrous tissue of SCL released NO, PGE2, and NMPs into the culture media. It is suspected that intralesional fibrous tissue may play an active role in the pathological process of bone resorption occurring in SCL in horses and may be partly responsible for the maintenance, slow healing rate, and expansion of these lesions. CLINICAL RELEVANCE: Understanding the pathogenesis of SCL will help to establish successful therapy in horses affected with SCL.

Analysis of Variance↗
PubMedDate not supplied

A review of coronavirus infection in the central nervous system of cats and mice.

Feline infectious peritonitis (FIP) is a common cause of death in cats. Management of this disease has been hampered by difficulties identifying the infection and determining the immunological status of affected cats and by high variability in the clinical, pathological, and immunological characteristics of affected cats. Neurological FIP, which is much more homogeneous than systemic effusive or noneffusive FIP, appears to be a good model for establishing the basic features of FIP immunopathogenesis. Very little information is available about the immunopathogenesis of neurologic FIP, and it is reasonable to use research from the well-characterized mouse hepatitis virus (MHV) immune-mediated encephalitis system, as a template for FIP investigation, and to contrast findings from the MHV model with those of FIP. It is expected that the immunopathogenic mechanisms will have important similarities. Such comparative research may lead to better understanding of FIP immunopathogenesis and rational prospects for management of this frustrating disease.

Animals↗