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Biomedical subjects

C P Loehnen

Publications and source records attributed to C P Loehnen.

4 recordsLinked to original sources

Routine chest roentgenography in pregnancy.

In an effort to determine if routine prenatal chest roentgenograms were of practical value, the records of 12,109 consecutive deliveries at the Mayo Clinic were reviewed retrospectively. The roentgenograms were obtained during the first or second prenatal visit and additionally when warranted by notable symptoms or physical findings in subsequent prenatal visits. Forty-eight patients had appreciable roentgenographic abnormalities. The findings of the general medical examination (which was routinely done at the first prenatal visit) were reviewed to determine if the chest abnormalities would have been suspected from the results of physical examination alone. In every case, a positive history or abnormal physical finding would have suggested the presence of the major abnormality or of the need for roentgenography to be performed.

Adolescent↗

Proliferative reactivity of T cells to autologous, cell-associated antigens.

T cells capable of proliferating in response to signals from autologous cells can be demonstrated in normal peripheral blood. The stimulating cell is contained among populations enriched in B cells, "null" cells, and monocytes, but not among populations enriched in T cells. Density gradient fractionation indicated that the autologous reactive T cell may represent a subpopulation of cells responsive in allogeneic mixed lymphocyte cultures. This was confirmed by negative selection (BUDR and light) experiments which also indicated that the "autologous" stimulus can be mediated by at least some allogeneic cells. In a portion of patients with active systemic lupus erythematosus, autologous reactivity was reversibly blocked. Prior incubation of either responding T or stimulator cells at 37 degrees C restored this reactivity.

Autoantibodies↗

Immunoregulation and autoimmunity.

The immunologic responses, both cell-mediated and humoral, to exogenous antigens reflect a crucial balance between extrinsic forces which can either augment or suppress the reactivity of T and B effector cells. It is probable that similar immunoregulatory influences play a key role in maintaining tolerance to some self-antigens. Thus, despite the presence of cells potentially capable of reacting to autologous antigens, lack of autoimmunity might reflect either an absence of amplifying or a preponderance of suppressive immunoregulatory forces. Within this framework, data obtained indicating aberrances of immunoregulation in patients with systemic lupus erythematosus are discussed, specifically as the aberrances may be causally related to the autoimmune nature of this disease.

Animals↗