Ilan Hammel

Professor Ilan Hammel (1950-2016) will be remembered as an outstanding scientist, teacher and colleague.

Ilan was educated at Tel-Aviv University (1971-6; Chemistry, Biochemistry) and the Technion (1976-80; Immunology). Starting with his D.Sc. thesis and postdoctoral training (St. Louis,1980-2 and Harvard,1982-3), Ilan began a life-long study of the quantal basis of Golgi-derived vesicle/granule growth and information content as the basic fundamental unit for cell-cell communication. Using quantitative microscopy and mathematical modelling, Ilan established a broad and well-accepted view of the subject and became one of the leading experts in the field.

Ilan established the precision of the message conveyed by secretory vesicles as a function of their size and size distribution. His recent modeling gave a first-time insight into granule growth, inventory turnover, inventory management and a unified model of secretion rate. the formation of mature secretory granules that are multimers of unit granules provides a mechanism for mixing, in large granules, the contents of different unit granules and establishing a ‘vocabulary’. A short, regulated burst of 8-10 granules will generate a ‘message’ in cell-cell communication. Massive secretion is considered an ‘accident’.

Ilan was an enthusiastic teacher and frequently cited in the Rector’s list of excellent teachers. He was involved in teaching courses such as Biophysics of Proteins, Quantitative Microscopy, General Pathology, The Secretory Cell and Advanced Methodologies in Research Techniques.

In the Sackler Faculty of Medicine, Ilan served as chairman of the Department of Pathology, Head of the Graduate School and Head of the Combined Program in Medical and Life Sciences in Tel Aviv University and head of the EM unit. Ilan was also Head of the Israel Executive Committee of the International Foundation for Education (ISEF).

Ilan was Comptroller (1989-91) and Chairman (2000-4) of the Israel Society of Microscopy and Member of the Board of Directors of the Israel Society of Histochemistry and Cytochemistry.

Besides his academic activities, Ilan was very proud of his volunteering work: teaching mathematics in elementary schools, instructing children with disabilities, lecturing in schools of the Arab community, refereeing in school science competitions and patrolling duties with the border police.

Ilan and I were associated for over 25 years through our joint interest in quantitative microscopy and concern regarding the state of biological EM in Israel. We observed the exponential rise of biological EM all over the world and its concomitant decline into rudimentary service units in our universities without our voices being heard. On the other hand, we refined methods to deduce physical properties of biological polymers from their EM images and tried to spread the ideas of quantitative microscopy through our teaching. Ilan made the extreme effort to come twice a year to Jerusalem to lecture on stereology and morphometry and was always available. One rarely meets a more generous colleague, dedicated teacher and original scientist than Ilan.

Shlomo Trachtenberg