Stimulating Materials obtained from Injured and Killed Cells

Proliferation-promoting intercellular hormones

“…2), though the difference in activities of injured cell and uninjured cell preparations was always of markedly lower order than that obtained under aerated conditions. The evidence of 'wound hormone' activity in aerated cultures of injured cell products which failed to exhibit such activity under non-aerated growth conditions, together with the previously mentioned results of Fardon, Carroll & Ruddy [1937] and Fardon, Norris et al; indicating respiratory-stimulating activity of such materials suggest a relationship to respiratory enzymes of the active factors in preparations from ultraviolet-injured yeast. The ultraviolet absorption spectra of the injured cell products showed a maximum at 2600A., characteristic of purines and pyrimidines, with an -extinction coefficient markedly higher than that in the spectra of uninj'ured cell products, in -agreement with reports of similar preparations from both yeast and animal tissues fLoofbourow, Cook & Stimson, 1938;Cook, Loofbourow & Stimson, 1939].…”

Investigation of the Production of Growth-Promoting and Growth-Inhibiting Factors by Ultra-Violet Irradiated Microörganisms

“…Recently, various investigations have lent support to the positive point of view. Thus, our coworkers and ourselves published evidence in 1937 that yeast and animal tissue cells injured by ultra-violet radiation release proliferation-promoting factors into the suspending medium (Fardon, Norris, Loofbourow and Ruddy, 1937;Sperti, Loofbourow and Dwyer, 1937a, b). Concurrent investigations of Florence Meier indicated that sub-lethal doses of ultra-violet stimulate the proliferation of unicellular green algae.…”

Historical foundations of wound healing and its potential for acceleration: dose‐response considerations

“…If the residual filtrate contained wound hormones, then this filtrate medium would be expected to stimulate the growth of normal yeast cells. In fact, this enhanced growth is what the investigators observed . Other findings revealed that the growth stimulation response to injury was not unique to yeasts nor was it only inducible by UV.…”