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Biomedical subjects

G S Johnson

Publications and source records attributed to G S Johnson.

At least 37 records · Page 2Linked to original sources
PubMed1998

Expression and location of pro-apoptotic Bcl-2 family protein BAD in normal human tissues and tumor cell lines.

The BAD protein is a pro-apoptotic member of the Bcl-2 family whose ability to heterodimerize with survival proteins such as Bcl-X(L) and to promote cell death is inhibited by phosphorylation. Monoclonal antibodies were generated against the human BAD protein and used to evaluate its expression by immunoblotting and immunohistochemistry in normal human tissues and by immunoblot analysis of the National Cancer Institute anti-cancer drug screening panel of 60 human tumor cell lines. BAD protein was detectable by immunoblotting in many normal tissues, with testis, breast, colon, and spleen being among those with the highest steady-state levels. Immunostaining of tissues revealed many examples of cell-type-specific expression of BAD, suggesting dynamic regulation of BAD protein levels in vivo. In many types of normal cells, BAD immunoreactivity was associated with cytosolic organelles resembling mitochondria, suggesting that BAD is often heterodimerized with other Bcl-2 family proteins in vivo. The relative levels of BAD protein varied widely among established human tumor cell lines, with colon, lung, and melanomas generally having the highest expression. As a group, hematopoietic and lymphoid lines contained the least BAD protein. The BAD protein derived from 11 of 41 tumor lines that expressed this pro-apoptotic protein migrated in gels as a clear doublet, consistent with the presence of hyperphosphorylated BAD protein. Taken together, these findings define for the first time the normal cell-type-specific patterns of expression and intracellular locations of the BAD protein in vivo and provide insights into the regulation of this pro-apoptotic Bcl-2 family protein in human tumors.

Antibodies, Monoclonal↗
PubMed1998

Risk of cancer mortality among the Longitudinal Study of Astronaut Health (LSAH) participants.

BACKGROUND: The potential for occupational radiation exposures in the U.S. Space Program makes cancer risk a major health concern. METHODS: The NASA Medical Operations Branch and KRUG Life Sciences Epidemiology Section at the Johnson Space Center (JSC) investigated the rate of cancer mortality among the astronauts and the comparison participants of the Longitudinal Study of Astronaut Health (LSAH). Medical records are maintained by the JSC Flight Medicine Clinic, JSC Occupational Medicine Clinic, and LSAH. Cause of death data from death certificates were reviewed for cancer mortality. These data were compared with cancer mortality data for the general population residing in the Texas Gulf Coast area. RESULTS: The astronauts had a higher age-specific risk of cancer mortality than the comparison group (SMR = 345; 95% CI = 69.5-756.2), but the difference did not reach statistical significance. Both the astronauts and the comparison group had lower age-specific rates than the general population (SMR = 47, 95% CI = 9.6-105.1; SMR = 17, 95% CI = 3.5-37.9, respectively).

Adult↗