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Biomedical subjects

R Wyler

Publications and source records attributed to R Wyler.

At least 55 records · Page 3Linked to original sources
PubMed1984

Induction of chemiluminescence during interaction of tumoricidal effector cell populations and tumor cells is dependent on the presence of mycoplasma.

A variety of host cells, such as activated macrophages, natural killer (NK) cells, and polymorphonuclear leukocytes (PMNL), are cytotoxic for an array of non-antibody-coated tumor cells. Because such effector cells appear to use oxygen-dependent mechanisms to effect tumor cell destruction in certain systems, the possibility of an involvement of toxic oxygen species has been considered. To investigate whether interaction of effector cells with neoplastic cells induces the generation of reactive oxygen species, resting and activated rat macrophages and rat spleen cells (as a source of NK activity) were exposed to viable tumor cells of varied origin, and chemiluminescence was monitored. This sensitive indicator of reactive oxygen generation was stimulated only when tumor cells or culture supernatants were contaminated with mycoplasma. Mycoplasma-free tumor cells and culture supernatants were in no case able to trigger chemiluminescence in any of these effector cell populations. On the other hand, tumor targets were equally susceptible to killing by effector cells irrespective of whether mycoplasma were present. The data suggest that generation of chemiluminescence during interaction of natural cytotoxic cells and neoplastic cells is an artifact and that reactive oxygen species do not function as an effector mechanism in antibody-independent natural killing effected by activated macrophages and NK cells.

Animals↗
PubMed1983

The chemiluminescent response of bovine polymorphonuclear leucocytes isolated from milk and blood.

Polymorphonuclear leucocytes (PMN) were isolated from milk and blood of healthy cows, and the generation of reactive oxygen by the two cell populations was compared by measuring chemiluminescence (CL) after stimulation with zymosan. The ratio of milk to blood PMN CL was relatively constant in a given animal, but varied widely between different cows, ranging from 0.3 to 1.3. The relative contributions of various oxygen species to CL was studied by measuring quenching using different oxygen scavengers. While the relative contributions of H202, -02 and '02 seemed to be similar in both milk and blood PMN, the OH. radical was clearly more prominent in PMN isolated from milk than from blood. In addition, blood PMN CL was more dependent on the presence of glucose in the reaction medium than milk PMN CL. Furthermore, the CL response to phorbol myristate acetate, to the Ca ionophore A23187 and to Sendai virus was different in the two cell types. The results suggest that CL generation in milk PMN differs from that in blood PMN in quantitative as well as qualitative aspects.

Animals↗
PubMed1983

Characterization of Trypanozoon stocks by isoelectric focusing and isoenzyme analysis.

Isoelectric focusing on ultrathin polyacrylamide foils, coupled with isoenzymatic analysis using five different enzymes, was used to characterize blood-forms of T.b. brucei, T.b. rhodesiense and T.b. gambiense and procyclic forms of T.b. brucei and T.b. rhodesiense. The protein concentrations in the lysates were quantified. Qualitative as well as quantitative differences were found.

Animals↗
PubMed1982

DNA of bovine herpesvirus type 1 in the trigeminal ganglia of latently infected calves.

Twelve calves infected with bovine herpesvirus type 1 (BHV-1) were killed when in a latent state of infection. Latency was verified 30 days after virus inoculation of the calves by seroconversion, absence of virus shedding, and in 2 calves, by recrudescence of the infection after they were treated with dexamethasone. By in situ hybridization techniques and autoradiography, DNA of BHV-1 was detected in 13 of 23 trigeminal ganglia of latently infected calves. Viral DNA was restricted to the nucleus of nerve cells. Single neurons harboring BHV-1 DNA were observed in 4.9% of the sections (n = 325) of the trigeminal ganglia. The results obtained correspond to those known from herpes simplex virus infections in mice. The implications for the virus-host relationship are discussed.

Animals↗
PubMed1981

[The transmission of tick-borne encephalitis in Switzerland. An attempt at establishing a register of natural reservoirs for a seroepidemiologic examination of forest personnel in the middle of the country].

The aim of this investigation was to localize natural foci of tickborne encephalitis (TBE) in Switzerland by means of two approaches. (1) Sera of foresters, who are particularly exposed to TBE, were examined, restricting serum collection to the Plateau between the Lake of Constance and the Lake of Geneva. (2) Virus isolations were performed on 8600 ticks (Ixodes ricinus) collected all over the country. In four regions natural foci of varying size were detected: (1) in the northern parts of the Canton of Zurich in conjunction with the southern parts of the Canton of Schaffhausen, (2) in the region of Horgen on the Lake of Zurich, (3) in the region of Thoune, and (4) in the marshy region situated between the Lakes of Neuchâtel, Bienne and Morat. The morbidity rate in foresters varied from 0-5%, and rose to 12-16% in regions with a known concentration of natural foci. The infection rates in ticks average 0.1%, but, depending on the regions where ticks were collected, maximum rates of 1% were attained.

Antibodies, Viral↗
PubMed1981

Detection of H-2 and Sendai virus antigens by chemiluminescence.

Two monoclonal antibodies reacting with Ia9 and H2.2, respectively, have been added to spleen cell suspensions prepared from mice of different H-2 haplotypes. Cellular light emission was monitored in a liquid scintillation spectrometer operated in the out-of-coincidence mode. The antibodies stimulated chemiluminescence (CL) in cells possessing the target antigenic determinant, but were inactive in cells lacking the determinant. In addition, CL could be stimulated in Sendai virus-infected spleen cells with anti-Sendai antibodies. The results demonstrate that CL measurement is a sensitive and simple method for the detection of cell surface antigens and for the screening of antibodies reacting with these antigens.

Animals↗