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Biomedical subjects

F Lechner

Publications and source records attributed to F Lechner.

At least 37 records · Page 2Linked to original sources
PubMed1997

Expression of cytokine mRNA in lentivirus-induced arthritis.

Infection of goats with the lentivirus caprine arthritis encephalitis virus (CAEV) leads to persistent infection and development of chronic arthritis. We analyzed the expression of cytokines and viral RNA in the joints of goats at early time points after experimental infection with CAEV and in those of animals suffering from chronic arthritis as a result of natural infection. In situ hybridization experiments showed that the pattern of cytokine expression in caprine arthritis was similar to that found in rheumatoid arthritis (RA), with a few cells expressing the lymphocyte-derived cytokines interferon (IFN)-gamma and interleukin (IL)-2 and rather more cells expressing monocyte chemoattractant protein (MCP)-1, IL-6, and tumor necrosis factor (TNF)-alpha. IFN-gamma mRNA expression in experimentally infected joints peaked at day 12 and was mostly detected in areas containing viral RNA. At later time points, no IFN-gamma- or virus-expressing cells were found in inflamed joints but both were again detected in goats with severe arthritis. Interestingly, at the clinical stage of arthritis reflecting the chronic stage of infection, the inflammatory lesion was found to be immunologically compartmentalized. Humoral immune responses and cell-mediated immune responses appeared to concurrently occur in distinct areas of the synovial membrane.

Animals↗
PubMed1996

Expression of TNF alpha in arthritis caused by caprine arthritis encephalitis virus.

Goats infected with caprine arthritis encephalitis virus (CAEV) develop chronic arthritis sharing many features with human rheumatoid arthritis (RA). TNF is thought to be a key mediator contributing to the formation of the arthritic lesion in RA. We studied this cytokine in goats suffering from chronic arthritis. TNF alpha expressing cells were detected by in situ hybridization in synovial membranes of arthritic carpal joints. Expression of TNF alpha did not correlate with the degree of viral replication as assessed by in situ hybridization for viral RNA. In line with the lack of correlation between the degree of viral replication and TNF expression in vivo, we failed to detect increased cytokine RNA in goat macrophages infected with CAE virus in vitro and no TNF protein was found in culture supernatants. In addition, virus infection failed to prime goat macrophages for enhanced TNF expression in response to lipopolysaccharide. Taken together, these findings argue against a direct role of CAE virus in increasing the expression of TNF alpha in caprine arthritis.

Animals↗
PubMed1994

MHC class I and non-MHC-linked capacity for generating an anti-viral CTL response determines susceptibility to CTL exhaustion and establishment of virus persistence in mice.

The influence of the murine MHC gene complex H-2 class I alleles or of the genetic background and the role of virus variants on establishment of a persistent infection with lymphocytic choriomeningitis virus (LCMV) was analyzed in immunocompetent mice of H-2d haplotype by evaluation of cytotoxic T cell responses. Susceptibility to establishment of a virus carrier state increased in various H-2d mice with lower CTL response and slower CTL kinetics. Low responder BALB/c-H-2dm2, lacking H-2Ld molecules to present the major T cell epitope amino acids 118-126 of the LCMV nucleoprotein or DBA/2 mice possessing relatively few CD8+ T cells, were more susceptible than high responder BALB/c mice expressing H-2Ld. Additional critical factors were LCMV isolate and dose of infection. The rapidly replicating LCMV-DOCILE and Cl 13 Armstrong induced viral persistence readily, whereas the slowly replicating parental virus strains WE or Armstrong did not. The presented findings illustrate a model of MHC-linked or MHC-unlinked susceptibility for virus persistence and may help to explain pathogeneses of chronic virus infections in humans that are often associated with slowly progressing immunopathology.

Animals↗
PubMed1993

Virus persistence in acutely infected immunocompetent mice by exhaustion of antiviral cytotoxic effector T cells.

Viruses that are non- or poorly cytopathic have developed various strategies to avoid elimination by the immune system and to persist in the host. Acute infection of adult mice with the noncytopathic lymphocytic choriomeningitis virus (LCMV) normally induces a protective cytotoxic T-cell response that also causes immunopathology. But some LCMV strains (such as DOCILE (LCMV-D) or Cl-13 Armstrong (Cl-13)) derived from virus carrier mice tend to persist after acute infection of adult mice without causing lethal immunopathological disease. Tendency to persist correlates with tropism, rapidity of virus spread and virus mutations. We report here that these LCMV isolates may persist because they induce most of the specific antiviral CD8+ cytotoxic T cells so completely that they all disappear within a few days and therefore neither eliminate the virus nor cause lethal immunopathology. The results illustrate that partially and sequentially induced (protective) immunity or complete exhaustion of T-cell immunity (high zone tolerance) are quantitatively different points on the scale of immunity; some viruses exploit the latter possibility to persist in an immunocompetent host.

Animals↗
PubMed1992

[The value of epidemiologic studies of ski injuries].

The Garmisch-Partenkirchen experience--15,513 skiing injuries between 1972 and 1990--was compared to the results of an inquiry into the skiing injuries among 565 persons of the medical profession, that were active skiers over an average of 18 years. The parameter injuries per 1000 skiing days was calculated from the outpatient clinic data as well as from all skiing injuries that had happened in the interview group and those that required surgical treatment. The mean value of 2.7 injuries/1000 skiing days--corrected for the number of patients--from the literature and the clinical data with 2.1 is comparable to the 1.8 injuries/1000 skiing days (injuries that required surgical treatment) but stands sharply against the 4.2 arising from the total number of injuries in the inquiry group.--Thus, every epidemiological study clearly underestimates the actual rate of skiing injuries. This fact may be defined as the "bypass-effect". The comparison between clinical setting and inquiry allowed for a quantification: Depending on the type of injury and the study design, a true prevalence of skiing injuries that is between 10% and 200% higher than the published data has to be expected.--Descriptive, not controlled epidemiologic studies on skiing injuries are justified and give valid trends on which therapeutic and prophylactic measures can be based--but exclusively under the following prerequisite conditions: 1. a standardized study protocol; 2. an observation.

Adult↗
PubMed1990

Evaluation of the API ATB 32C system for the rapid identification of foodborne yeasts.

The commercial API ATB 32C identification kit was compared with a standard method for identifying 11 reference strains and 53 yeast strains isolated from fermented milk products. Approx. 50% of the species considered in the API ATB 32C database were identified on a level of good, very good, and excellent identification. The numerical profile of 25 strains was not found in the API ATB 32C index. Low discrimination or misidentification was observed in seven strains. The low reliability of the API ATB 32C system may be ascribed to the incomplete nature of the profile index. A majority (91%) of the strains, however, were identified correctly by the API ATB 32C strip test results in combination with the commercial computer program of Barnett et al. (1985). This combined procedure offers the possibility to identify any out of 497 species considered by Barnett et al. (1985).

Animals↗
PubMed1990

Evaluation and reliability of a simplified method for identification of food-borne yeasts.

A simplified identification key described by Deak and Beuchat (T. Deak and L. R. Beuchat, J. Food Prot. 50:243-264, 1987) and the computer method of Barnett et al. (J. A. Barnett, R. W. Payne, and D. Yarrow, Yeast Identification Program, 1985) were used to identify 12 reference strains and 382 yeasts isolated from cultured milk products. Because the simplified key failed to account for species variability with regard to physiological, morphological, and sexual reproduction characteristics, poor agreement of the identification results was obtained. A reevaluation of the basic theoretical assumptions of the simplified key only confirmed the practical results and indicates that this identification method is unsatisfactory.

Journal Article↗
PubMed1987

Prophylaxis of deep vein thrombosis in high risk patients undergoing total hip replacement with low molecular weight heparin plus dihydroergotamine.

In 160 high risk patients with total hip replacement the antithrombotic efficacy and tolerance of a single daily injection of 1500 aPTT-U (aPTT = activated partial thromboplastin time) low molecular weight heparin plus 0.5 mg dihydroergotamine (HNMD; Embolex NM) was compared with a twice daily application of 5000 IU of the heparin-dihydroergotamine combination Heparin-Dihydergot in a double-blind study. Deep vein thrombosis measured by means of the radiofibrinogen uptake test occurred in 20.5% of patients in both groups. In addition, intra- and postoperative blood loss and the development of hematoma were similar in both groups. Thus, on account of the "once-daily" application HNMD offers some substantial advantages: The stress of the patient in the postoperative convalescence phase can be appreciably lowered and thereby the nursing staff are spared a great deal of work.

Adult↗
PubMed1986

[Treatment of chronic osteomyelitis with a collagen-antibiotic compound--preliminary report].

A compound of collagen and gentamicin was used in a controlled examination on 67 patients for the treatment of posttraumatic as well as postoperative osteomyelitis and, when applying cement-free endoprostheses, for hemostasis and local prevention of infection in the bed for implantation. Even in case of relatively high doses, the gentamicin concentration measured was only at the threshold value of detectability, due to the local application of the absorbable antibiotic compound. In most of all cases (n = 63), the healing of infection is demonstrated by clinical and radiobiological investigation.

Collagen↗
PubMed1986

[Experimental studies and clinical aspects of cold-preserved allogenic spongiosa].

Different temperatures, freeze techniques, and durations of storage for cryopreservation of allogeneic spongious bone were studied in an experimental model. Low temperatures (-70 degrees C to 196 degrees C) without cryoprotectants proved to be favorable in micromorphological as well as scintigraphic analyses. These transplants seem to be equivalent to fresh autologous transplants - at least in animal experiments. Medium-term durations of storage (3 mo) at low temperatures yield the best osteoinductive capacity. Long term storage (12 months) and radiosterilization reduce the quality of the allogeneic bone. The clinical results in 495 transplantations of cryopreserved allogeneic spongious bone confirm the experimental findings.

Animals↗
PubMed1983

[Demonstration of a full crown with a diffusion chamber in the cat, for studies of dental pulp].

A step-by-step technique leading to the preparation of a full-crown with diffusion chamber in the cat, is presented. The crown is built according to the routine clinical technique. The diffusion chamber is prepared and sealed with the help of a specially adapted screw. A vital stain locked in the diffusion chamber did not show any leakage in the oral cavity, even after 3 months. Such a device could easily help to study the action of toxins and isolated antigens on the animals dental pulp.

Animals↗