Biomedical subjects
T J Denton
Publications and source records attributed to T J Denton.
High-level expression and purification of biologically active recombinant pokeweed antiviral protein.
Pokeweed antiviral protein (PAP) from the leaves of the pokeweed plant, Phytolacca americana, is a naturally occurring single-chain ribosome-inactivating protein, which catalytically inactivates both prokaryotic and eukaryotic ribosomes. The therapeutic potential of PAP has gained considerable interest in recent years due to the clinical use of native PAP as the active moiety of immunoconjugates against cancer and AIDS. The clinical use of native PAP is limited due to inherent difficulties in obtaining sufficient quantities of a homogenously pure and active PAP preparation with minimal batch to batch variability from its natural source. Previous methods for expression of recombinant PAP in yeast, transgenic plants and Escherichia coli have resulted in either unacceptably low yields or were too toxic to the host system. Here, we report a successful strategy which allows high level expression of PAP as inclusion bodies in E. coli. Purification of refolded recombinant protein from solubilized inclusion bodies by size-exclusion chromatography yielded biologically active recombinant PAP (final yield: 10 to 12 mg/L). The ribosome depurinating in vitro N-glycosidase activity and cellular anti-HIV activity of recombinant PAP were comparable to those of the native PAP. This expression and purification system makes it possible to obtain sufficient quantities of biologically active and homogenous recombinant PAP sufficient to carry out advanced clinical trials. To our knowledge, this is the first large-scale expression and purification of biologically active recombinant PAP from E. coli.
Orthopedic manpower.
Key statistical information regarding Orthopedic Manpower is present to make orthopedists aware of the detailed information that is currently available. It is clear there is still insufficient data to justify radically altering the numbers or types of practices. Until the scope of orthopedic practice is more clearly defined and generally accepted (by orthopedists, other physicians, health professionals and the public) we must continue to monitor our activities and make adjustments through evolutionary changes rather than revolutionary regulations. Quite clearly there are segments of our country that are orthopedically underserved. Thus, it is vital that we seek new methods to encourage orthopedists to settle in these areas. Clearly, the simple production of more orthopedists in the traditional model will not answer the geographic maldistribution. With the tremendous scope of problems cared for by orthopedists, there does not appear to be an oversupply; however, we are headed in that direction. If we continue to rate operative procedures as the most significant and satisfying aspect of the practice, we certainly have enough, but they are not spread across the country in a uniform manner. Significant increases in numbers will be necessary if the orthopedist is to assume the role of general practitioner of the musculoskeletal system as well as a specialist for diagnosing and treating the more complicated musculoskeletal problems (whether by medical-surgical or physical-medical modalities). Should this be the case adjustments must be made in the selection process of orthopedic residents, in training programs, as well as estimates of the numbers of such specialists necessary for the future.