Charles Philippe Leblond : biography
"Retirement" and later days
At 65, instead of retiring, Leblond continued his research with an NIH Fogarty Scholarship at the National Institute of Dental Research, where he learned about immunohistochemistry. This launched a twenty-year molecular exploration culminating in the concept of the basement membrane as an integrated polymer, rather than as layers of separated macromolecules initially favored by others.
Leblond continued to attend all weekly departmental seminars well into his 90’s and continued to publish in peer-reviewed journals into the new millennium. He learned to use a computer at age 90, starting a presentation at an international conference back in 2004, by noting: "A month ago, I thought Power Point was a tool for sharpening pencils."
His total contributions resulted in the publication of 430 scientific papers, many of them still frequently cited. In late September 2006, he published his final article—about detecting the MMP9 cysteine activation switch for the first time in remodeling cartilage.Lee ER, Lamplugh L, Kluczyk B, Mort JS, Leblond CP. Protease analysis by neoepitope approach reveals the activation of MMP-9 is achieved proteolytically in a test tissue cartilage model involved in bone formation. J Histochem Cytochem. 2006 Sep;54(9):965-80. Epub 2006 May 18.
Leblond was preceded in death by his wife of 64 years, Gertrude Sternschuss, who died in 2000. After Gertrude died, Leblond married a childhood friend, Odette Lengrand, in 2001; they were both 91. Odette died in 2004.
Main research interests
In 1946, Leblond found that, when he poured liquid photographic emulsion on a histological section containing a radio element, the emulsion was eventually activated by the radio-element; and if thereafter routine photographic development and fixation were applied to the emulsion-covered section, black silver grains appeared in the emulsion wherever it overlay sites containing a radio-element. This liquid emulsion approach has been used to develop a new High Resolution Autoradiography procedureBélanger, L.F. and C.P. Leblond. A method for locating radioactive elements in tissues by covering histological sections with a photographic emulsion. Endocrinology. 1946, 39, 386-400. characterized by close contact between emulsion and section. Such close contact makes it possible to localize the radio-elements in the section at high resolution, so that radio-elements can be localized at high magnification in the light microscope.Gross, J., R. Bogoroch, N.J. Nadler and C.P. Leblond. The theory and methods of the radioautographic localization of radio elements in tissues. Amer. J. Roentgenoi. 1951, 65, 420-468.Kopriwa, B. and C.P. Leblond. Improvements in the coating technique of radioautography. J. Histochem. Cytochem. 1962, 10, 269-284.
This procedure has been utilized to examine some of the dynamic features of body components, with the main findings as follows:
- The existence of stem cells in adult organs, as shown by autoradiography with labeled thymidine.
- The continuity of protein synthesis in living cells, as shown by autoradiography with labeled amino acids.
- The key role of the Golgi apparatus in protein glycosylation, as shown by autoradiography with labeled hexoses.
His results threw doubt on the validity of three traditional concepts dear to biologists in the earlier part of the twentieth century: "stability" of the cell, in which the cell and its components are unchanging, permanent structures; "specificity" of cell function, in which each cell type has a distinct, unique function; and "activity-rest alternation" of cell function, in which each period of cellular activity is followed by a period during which the activity ceases.
He has proposed replacing cell "specificity" by "multipotentiality", "activity-rest alternation" by "continuity" and "stability" of cell components by "renewal". These various results have provided the foundation not only for modern stem cell research, but also for modern cell biology.
As Nobel laureate George Palade noted on the occasion of the 1992 Prix Marie-Victorin to Leblond, Charles Leblond’s discoveries are so fundamental that they are taught in schools and colleges throughout the world.