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Biomedical subjects

M Thoman

Publications and source records attributed to M Thoman.

13 recordsLinked to original sources
PubMed1997

Transforming growth factor-beta 1 induces antigen-specific unresponsiveness in naive T cells.

Transforming growth factor-beta 1 (TGF-beta 1) is a cytokine with complex immunomodulatory effects including the ability to inhibit the onset or severity of autoimmune disease. This study was designed to test the possibility that one mechanism by which TGF-beta 1 exerts its immunosuppressive effects is by inducing antigen (Ag)-specific unresponsiveness in CD4+ cells. TGF-beta 1 was shown here to inhibit the Ag-specific proliferation of naive CD4+ cells from T cell receptor (TCR) transgenic mice. More importantly, the naive CD4+ cells exposed to TGF-beta 1 and Ag, but not to TGF-beta 1 alone, in primary cultures were unable to proliferate or secrete IL-2 in response to a subsequent Ag challenge following removal of TGF-beta 1 from the cultures. Anti-CD28 mAb partially blocked the Ag-specific inactivation induced by TGF-beta 1 in naive CD4+ cells. The inhibitory effects of TGF-beta 1 on CD4+ cells are not mediated by alterations in APC costimulation since TGF-beta 1 did not inhibit the Ag-induced expression of MHC class II molecules, CD80 or CD86 on splenic APC. Taken together, the results suggest that the immunosuppressive activities of TGF-beta 1 encompass direct induction of Ag-specific unresponsiveness in naive CD4+ cells.

Animals↗
PubMed1990

Toxicokinetics of Bordetella pertussis.

Pertussis vaccine immunization is required in most of the 50 states in the United States. Since it is required or recommended it is imperative that the clinician give this vaccine, crude as it is, in the safest possible environment. Giving specific active (verbal) as well as passive (written) instructions to the parent or caretakers is mandatory. If in doubt, defer or delete the pertussis portion.

Bordetella pertussis↗
PubMed1978

Nuclear surface complex as observed with the high resolution scanning electron microscope. Visualization of the membrane surfaces of the neclear envelope and the nuclear cortex from Xenopus laevis oocytes.

The nuclear envelope and associated structures from Xenopus laevis oocytes (stage VI) have been examined with the high resolution scanning electron microscope (SEM). The features of the inner and outer surfaces of the nuclear surface complex were revealed by manual isolation , whereas the membranes facing the perinuclear space (the space between the inner and outer nuclear membranes) were observed by fracturing the nuclear envelope in this plane and splaying the corresponding regions apart. Pore complexes were observed on all four membrane surfaces of this double-membraned structure. The densely packed pore complexes (55/micron2) are often clustered into triplets with shared walls (outer diameter = 90 nm; inner diameter = 25 nm; wall thickness = aproximately 30 nm), and project aproximately 20 nm above each membrane except where they are flush with the innermost surface. The pore complex appears to be an aggregate of four 30-nm subunits. The nuclear cortex, a fibrous layer (300 nm thickness) associated with the inner surface of the nuclear envelope, has been revealed by rapid fixation. This cortical layer is interrupted by funnel-shaped intranuclear channels (120-640 nm diam) which narrow towards the pore complexes. Chains of particles, arranged in spirals, are inserted into these intranuclear channels. The fibers associated with the innermost face of the nuclear envelope can be extraced with 0.6 MKI to reveal the pore complexes. A model of the nuclear surface complex, compiled from the visualization of all the membrane faces and the nuclear cortex, demonstrates relations between the intranuclear channels (3.2/micron2) and the numerous pore complexes, and the possibility of their role in nucleocytoplasmic interactions.

Animals↗
PubMed1973

Changes in isozyme patterns between monokaryons and dikaryons of a bipolar Coprinus.

Proteins and isozymes of several different classes of enzymes in partially purified protein extracts of monokaryons, dikaryons, and monokaryon mixtures of a bipolar Coprinus sp. were separated on polyacrylamide gels by slab electrophoresis. Differences in protein and isozyme spectra were correlated with the operation of the incompatibility factors and with the results of Wang and Raper on Schizophyllum. It was concluded that the shift from monokaryon to dikaryon mediated a major change in the nature, quantity, or distribution of the proteins of this Coprinus sp.

Aminopeptidases↗
PubMed1972

A factor that can be used to regulate an in vitro primary immune response.

A factor has been isolated that supports the stimulation of an immune response against heterologous erythrocyte antigens in mouse spleen cells cultured in a medium that contains deficient serum. The factor is secreted by certain spleen cells that are obtained in permanent culture after leukemia virus infection. The factor permits antigen-sensitive cells derived from bone marrow to mature to antibody-forming cells. This factor can be used in controlling the initiation of a primary immune response in vitro.

Animals↗