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Biomedical subjects

H Tuschl

Publications and source records attributed to H Tuschl.

25 records · Page 2Linked to original sources
PubMed1976

Unscheduled DNA synthesis in lymphocytes of rheumatoid arthritis patients and spleen cells of rats with experimentally induced arthritis.

DNA repair is an important factor in the abolition or manifestation of mutations. Since intrinsic somatic mutations may be related to the occurrence of autoimmunity, DNA repair was investigated by measuring unscheduled DNA synthesis in lymphocytes of rheumatoid arthritis patients by autoradiography. Likewise, unscheduled DNA synthesis was investigated in mycoplasma- and Freund's adjuvant-induced arthritis in rats. Both in human rheumatoid arthritis and experimentally-induced arthritis the capacity for repairing lesions in DNA induced by gamma-irradiation of cells was reduced, while an increased rate of thymidine-incorporation into DNA was found after UV-irradiation. The results are discussed in relation to endonucleases of viral or mycoplasmal origin.

Animals↗
PubMedDate not supplied

Immunological investigations in a group of workers exposed to various levels of polycyclic aromatic hydrocarbons.

To evaluate a possible immunotoxic effect of chronic exposure to polycyclic aromatic hydrocarbons (PAHs), several immune parameters were investigated in two groups of coke-oven workers. Exposure levels were different for both groups, one group being employed in a new coking facility of sophisticated technical standard, and the other in a facility with rather high emission of PAH-containing dust, built during the late 1960s. Immunomodulating effects of exposure were found on three levels of immunity: a reduced mitogenic response of T cells to phytohaemagglutinin observed by a reduced rate of DNA synthesis and a retardation in the expression of interleukin 2 receptor; an impairment of B cell activity, observed by a reduced proliferation of B cells and a low synthesis of immunoglobulin M after Staphylococcus aureus stimulation; a reduced oxidative burst in monocytes after challenge with E. coli. The differences in numbers of lymphocytic subpopulations in peripheral blood and in immunoglobulin levels of serum were statistically insignificant. The data of the present investigations point to significant, albeit slight, changes in immune function by PAH exposure. But these changes could not yet be related to health impacts of the exposure.

Adult↗
PubMedDate not supplied

Investigations on immune parameters in welders.

The aim of the present investigation was to study the effects of welding fumes on the human immune system. Thirty male subjects who had regularly welded and 16 control persons without occupational exposure were examined. Cellular immunity was evaluated by phenotyping of peripheral leucocytes, measurement of mitogenic T cell response and T cell stimulation in a heterologous mixed lymphocyte reaction. Non-specific immune reactions were quantified by oxidative burst of granulocytes and monocytes and the cytotoxicity of lymphokine-activated killer (LAK) cells. Serum immunoglobulin levels and immunoglobulin production by stimulated B cells served to demonstrate humoral immune reactions. Welding fumes retarded the kinetics of DNA synthesis after phytohaemagglutinin stimulation of T cells and reduced the cytotoxic activity of LAK cells. No effects on lymphocytic subpopulations, mixed lymphocyte reaction, the phagocytosis of leucocytes or the production of immunoglobulins were observed. Several welders reported on recurrent respiratory infections or bronchitis, a few on allergic skin reactions and one worker was affected by asthmatic symptoms. With the exception of a reduced activity of LAK cells, these effects could not be related to any impairment of immune reactions as they were measured by the immunotoxicity tests applied.

Adolescent↗
PubMedDate not supplied

Langerhans cells and immature dendritic cells as model systems for screening of skin sensitizers.

Langerhans cells are the most potent antigen-presenting cells in the skin and play a critical role in the induction of contact allergy. Research on the phenotypical and functional changes of LCs occurring after application of skin sensitizers indicated their use as an in vitro model for the screening of chemicals. In the present investigations, LCs from human skin explants served as the test system. The application of this cell system has been aggravated by the difficulty in isolating sufficient numbers of live LCs from skin. This disadvantage was overcome by the culture of immature dendritic cells from peripheral mononuclear blood cells. These cells can serve as a replacement for LCs as they bind haptens and show phenotypical and functional changes similar to LCs. The sensitizers NiSO(4), dinitrochlorobenzene, 2,4,6-trinitrobenzene sulfonic acid, alpha-hexylcinnamaldehyde and eugenol were applied. Both the expression of surface markers and the induction of intracellular interleukin-1 beta (IL-1 beta) were analyzed. No clear-cut results could be established for intracellular cytokine production, only NiSO(4) induced a remarkable number of IL-1 beta-positive cells. However, all skin sensitizers caused an up-regulation of the co-stimulatory molecule CD86, of intercellular adhesion molecule CD54 and of the HLA-DR antigen. The irritant sodium dodecyl sulfate (SDS) and the vehicle dimethyl sulfoxide (DMSO) had no effect.

Acrolein↗
PubMedDate not supplied

[DNA repair in murine lupus].

DNA repair was investigated in New Zealand Mice strains which develop murine lupus, and compared with Swiss control mice. Unscheduled DNA synthesis demonstrated by autoriadiography was used to measure the repair capacity of spleen cells. After gamma-irradiation DNA repair was decreased in the autoimmune strains, while it was significantly increased after UV-irradiation. A possible relationship between repair capacity after gamma-respectively UV-irradiation and the etiologic factor of autoimmunity is discussed.

Age Factors↗