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Editorial

Moshe Wolman is considered as the father of histochemistry as a science in Israel. His contributions to histochemistry are extensive and he is a member of the small group of distinguished histochemistry pioneers in the world. This brief profile reviews some of the highlights of a lifetime devoted to develop histochemistry and its applications in pathology.

The early years

Moshe Wolman was born in 1914 in Warsaw, Poland. He immigrated to Palestine (then under British Mandate) as a child in 1925. He studied medicine in Italy (Florence 1932-1935 and Rome, 1935-1938) and qualified as an MD in 1938. The period 1938-1959 was spent in Jerusalem with the exception of his service in East Africa in the British Forces (1941-1946). In the period 1938 to 1940, he worked in the Cancer Research Institute of the Hebrew University. Afterwards, he was employed in the Department of Internal Medicine of the Hadassah University Hospital where he later served as a resident. In both institutions, he was engaged in scientific research and published a series of papers. In the late 1940s, he volunteered to serve in the British Army and joined the 101 Military Mission (the famous Gideon Force of Orde Wingate). He was involved in the operation in 1941 that brought Haile Selassie back to occupied Ethiopia and served as a medical officer in the emperor's camp. Moshe Wolman was in charge of a medical ward and clinical laboratory in the Menelik Hospital in Addis Ababa in the period 1941-1944 and during this period published scientific papers on louse-- borne relapsing fever and typhus. In 1944, he was posted in the Central Pathology Laboratory of the Middle East Forces located in the 15th Scottish General Hospital in Cairo, Egypt. There he participated in an advanced training course in pathology and supervised the testing of drugs for the treatment of relapsing fever on request of the British Medical Research Council in London, UK. In 1945 after completion of the course, he was appointed as head of the Pathology Laboratory of the 27th General Hospital in Tel-El-Kabir, Egypt.

His early research in histochemistry

After his release from the army in 1946, Moshe Wolman joined the Department of Pathology of the Hadassah Hospital in Jerusalem (headed by professor E.E. Franco) where he started as assistant and finally became chief physician. Moshe Wolman was the first person in Israel that was involved in histochemical research and during the decade 1946-1956, he had the stage virtually for himself. The first histochemical article as a result of his research was published with professor Franco in 1947, and dealt with the accumulation of cerebrosides in cells in Gaucher's disease. In 1949, he was appointed as a member of the staff of the newly-founded Medical School of the Hebrew University and was provided with a minute laboratory in which he performed histochemical research.

In this period, he studied the chemical significance of the periodic acid-Schiff (PAS) staining method. He showed that the method is not specific for carbohydrates as was thought at that time, but also stains lipids. He also investigated the role of fixation in histochemical staining methods and how the various fixatives work. Moshe Wolman recalls a seminar that he gave in the new Medical School in which he discussed the principles of histochemical methods for the localization of enzymatic activities in fixed tissues that had just been introduced. The audience was extremely skeptical with respect to the demonstration of enzyme activity in tissues that had been exposed to harsh protein-denaturing fixatives followed by embedding in hot wax baths.

Learning from the leading histochemists

In 1951, Moshe Wolman received the Judah Magnes award allowing him to spend a sabbatical year abroad. He wanted to see for himself how the most famous histochemists of that period were solving basic problems in histochemistry and decided to visit the leading laboratories in the USA. His first stop was the laboratory of R.D. Lillie in the National Institutes of Health (NIH), Bethesda MD. R.D. Lillie was one of the developers of the PAS reaction and had published a paper shortly before Wolman's arrival claiming that Wolman's conclusions with respect to the specificity of the PAS staining method were misleading and wrong. Despite this principle difference in point of view, Moshe Wolman enjoyed a productive stay in Lillie's laboratory and both remained good friends. Moshe Wolman still does not know whether Lillie ever changed his opinion, despite the fact that Wolman's conclusions with respect to the PAS staining method became widely accepted. At that time, Lillie worked hard on his "classic" textbook (Lillie, 1954). After 3 months at NIH, Moshe Wolman moved to the laboratory of J. Friedenwald in the Eye Department of Johns Hopkins Hospital, Baltimore MD. Friedenwald was considered as one of the greatest scientists of his generation. He was expert in many disciplines in basic sciences from mathematics to physical chemistry, from clinical chemistry to pathology and applied this broad knowledge to solve problems in ophthalmology. Moshe Wolman enjoyed his stay with Friedenwald and his coworkers, especially because of the discussions leading to plausible explanations (based on advanced physical chemistry) for the secretion of hydrogen and hydroxyl ions by cells in organs such as the eye and stomach. Friedenwald had developed an apparatus at that time that enabled the preparation of thick frozen sections for enzyme histochemical purposes, which can be considered as a prototype of the cryostat.

The next laboratory he visited during his sabbatical year was that of A. Seligman at Beth Israel Hospital, Boston MA. Seligman was widely acknowledged as an outstanding scientist with first class expertise in organic chemistry and synthetic processes. In Seligman's laboratory, Moshe Wolman encountered a new instrument, the cryostat. He immediately started to cut cryostat sections, which provided confirmation that the histochemical localization of enzyme activity in fixed tissues was legitimate. Seligman developed many novel histochemical techniques and also synthesized the necessary substrates and chemicals. Seligman, together with Rivka Ashbel, a visiting biologist from Jerusalem, developed a staining method for fatty carbonyls and applied it as a dye for corticosteroids. The subject of fatty carbonyls was of special interest to Moshe Wolman as the oxidation of unsaturated fatty acids caused the production of carbonyls, peroxides, free radicals and subsequently pigmented fatty polymers (lipofuscins). Research of these processes took much of Moshe Wolman's time for several years, and owing to his expertise in the subject, he was invited by the US National Library of Medicine to write an authoritative book on this subject (Wolman, 1975).

During his period in Boston, Moshe Wolman took the opportunity to pay short visits to the laboratories of two of the greatest histochemists of that time. The first visit was to G. Gomori in Chicago IL, who is credited for the discovery of effective histochemical methods for localization of enzyme activity and whose textbook became the "classic" source of information on enzyme histochemistry (Gomori, 1952). The second visit was to the laboratory of D. Glick in Minneapolis, MN. Glick was one of the outstanding scientists involved in developing techniques in microchemistry.

On his way back to Israel, Wolman met A.G. Everson Pearse in London, UK, a young histochemist at the start of an illustrious career in histochemistry and pathology. Pearse's "classic" textbook (and the following editions) provided an enormous source of background information on the methodologies in histochemistry and applications to pathology (Pearse, 1953). Pearse probably did more than any other individual to establish histochemistry as a legitimate branch of science rather than a collection of techniques. Wolman then travelled to Brussels to visit L. Lison, the author of the first modern textbook in histochemistry (in French; Lison, 1953). Lison demonstrated to Wolman his method for the quantification of DNA in nuclei in sections stained with the Feulgen reaction.

Wolman's sabbatical coincided with the start of a golden era of histochemistry in which a group of truly outstanding and pioneering scientists with dynamic research laboratories popularized and established histochemistry as an important discipline in cell biology and pathology. Their "classic" textbooks helped to stimulate the widespread use of histochemical techniques in medical diagnosis and research which helped to establish histochemistry as a scientific discipline. The impact of their textbooks was enormous. The books are still widely consulted half a century after being written. During one tremendous and historical sabbatical year, Wolman managed to learn from all the outstanding pioneers in histochemistry of that time.

A productive research program

With the enormous amount of information acquired during his sabbatical, an enthusiastic Moshe Wolman returned to Israel with several different research directions in mind. Wolman's research included histochemistry of viral and non-viral inclusion bodies. He continued to study chemical fixatives and fixation techniques. His knowledge of physical chemistry enabled him to develop a technique to distinguish between strong and weak anionic charges. He showed that proteoglycans and polysaccharides of different pK values in their end groups, can be differentially stained. This resulted in the development of the Bi-Col procedure. This histochemical method was based on treating sections with a highly acidic colloidal iron solution (pH 2) followed by a positively charged colloidal gold solution at pH 5. The BiCol method was published in a not very-well known Israeli scientific journal and his research on the differential staining of acidic tissue components, especially in "ground substance", did not receive the recognition it deserved (Wolman, 1956). In fact, advances in our understanding of the chemical nature of "ground substance" remained largely neglected for a generation.

Wolman studied chemical factors underlying various impregnation procedures for the nervous system. He was also involved in research on demyelination of peripheral nerve sheaths and their staining with osmium tetroxide. In the mid 1950s, it was widely accepted that osmium tetroxide binds to and stains unsaturated lipids. Wolman showed that black osmium staining in light microscopy and its electron density for electron microscopy, appears first in carbohydrates before it stains unsaturated lipids. He showed that osmium tetroxide is first reduced in hydrophilic layers rather than in the hydrophobic layers of myelin in not completely blackened preparations. He also demonstrated the presence of a carbohydrate-containing moiety in myelin (later shown by others to be different proteoglycans) and its importance in myelin breakdown. His research was focused on the oxidation of lipids, the formation of lipid peroxides, their polymerization, and the pathogenesis and nature of lipid pigments. The fact that osmium could bind rapidly to reactive groups in glycosaminoglycans and proteins was quite revolutionary at the time. John Baker in Oxford, UK independently came to similar conclusions. Unfortunately, the binding properties of osmium tetroxide to non-lipid components of tissues are almost forgotten today.

Tel Hashomer and Tel Aviv

In 1959, Wolman was appointed as head of the Department of Pathology of the Tel Hashomer Government Hospital (later renamed as the Chaim Sheba Medical Center). In this stage, he was still virtually the only "histochemist" in Israel. In order to popularize the use of histochemical techniques in pathology and research, he organized a national course in 1963 that attracted pathologists, histologists, dentists and clinicians from everywhere in Israel. The course consisted of lectures and practical classes in general histochemistry and enzyme histochemistry. The enormous success of the course resulted in the widespread introduction of histochemical techniques in hospitals and research laboratories throughout Israel. Histochemical research flourished in his department in the Tel Hashomer Hospital, especially research on peripheral nerve demyelinization and membrane structures. Using enzymic histochemical methods, he and his co-workers were able to prove that changes in ion concentrations can induce phase changes in cell membranes. This was the first basic study on cell membranes in Israel. A study of Wolman, which had an impact on a hotly debated problem in pathology, dealt with the substance (or substances) called amyloid (Wolman, 1971). Amyloid deposition in various organs was (and still is) diagnosed with the use of a number of different technical procedures. Deposits that were demonstrafed by some techniques and diagnosed as amyloid were not demonstrated by other procedures. Slight variations in the procedures, as well as the optical quality of microscopes further complicated the issue. Wolman pointed out that the term "true amyloid" is meaningless and proposed an easily standardized procedure for demonstrating amyloid to avoid disagreements.

Understanding of the chemistry involved in histological and histochemical techniques enabled Moshe Wolman in the 1950s to determine that the storage disease, that was later named after him and is known as Wolman disease, is caused by accumulation in cells of a mixture of cholesterol and triglycerides and differed substantially from Niemann-Pick Disease. Later a group of English researchers discovered that the enzyme missing in this disease was a lysosomal lipase esterase. Wolman then suggested that this enzyme has an essential role in the pathogenesis of xanthomas and atherosclerosis. This idea was developed in collaboration with Gaton in his laboratory. It was demonstrated that the development of xanthomas and atheromas is accompanied and presumably caused by a too low acid esterase activity (Wolman, 1989).

Wolman and his co-workers in Tel Hashomer Hospital spent a large amount of energy to formulate the theory and use of polarization microscopy in routine pathology and diagnostic molecular research. Because they were the pioneers in the field, many requests were made by editors of journals and by histochemical societies for reviews on the use of polarization microscopy in interpretation of biological structures and in histopathological diagnosis. Polarized light microscopy is a powerful tool, which allows the detection of structures that can otherwise be obtained only with great difficulty. Most users of polarization microscopy do not have the necessary understanding of optics and, therefore, only a few institutes of cell biology and pathology actively pursued advanced studies in this field. Wolman tried to explain polarization optics to biologists and pathologists in simple terms (Wolman, 1970). Unfortunately, his attempts had little success so that the advanced studies of Wolman and scientists in other centers continued but could not stem the flow of inaccurate publications due to misunderstanding the principles of polarization microscopy.

In 1964, Wolman was appointed as full professor and head of the Department of Pathology at the newly founded Medical School of Tel Aviv University. In 1967, he established the Department of Cell Biology and Histology and introduced novel approaches in teaching (Wolman, 1985). He also served as its chairman. When it became feasible, he established rotating chairmanships in both departments and served a further term as chairman of the Pathology Department of the Tel Aviv University from 1979-1982.

Sabbatical research

In 1968-1969, Wolman spent a sabbatical year in the laboratory of E. Roberts (Department of Neurosciences, City of Hope Medical Center, Duarte CA, USA). In another sabbatical year in 1977-1978, he divided his time between the University of Western Australia (with M. Walters), a lecture tour to 7 universities in Japan, the National Institute of Nervous Diseases and Stroke, Bethesda (with I. Klatzo) and the Centre de Neurochimie, University of Strasbourg, France (with P. Mandel).

Honors and publications

For a half-century, Moshe Wolman has been a member of the Histochemical Society (USA), the Society for Experimental Biology and Medicine and the Israel Association of Pathologists and (since 1959) the Gesellschaft fur Histochemie (at present the Society for Histochemistry). In 1966, Moshe Wolman was elected as a member of the prestigious Deutsche Akademie der Naturforscher Leopoldina. In 1984, he founded the Israel Society for Histochemistry and Cytochemistry and served as its President until 1990.

Moshe Wolman is author of more than 200 publications and contributions to books. In the mid 1950s, he was invited by the editors of the trilingual Handbuch der Histochemie to write a volume on the histochemistry of lipids. His volume, "Histochemistry of lipids in pathology", an encyclopedic book of over 700 pages and more than 3000 references, was published in English (Wolman, 1964).

Over the years, he contributed to books with many chapters and has served on numerous editorial boards including Histochemie (1958). He is still actively writing (in a very precise longhand) and his wisdom extends to many fields beyond pathology and histochemistry (Wolman, 1985; Kopolovic and Wolman, 1996).

Moshe Wolman has received many distinguished awards and honors. He was the first recipient of the Pearse Prize for Histochemistry awarded by the Royal Microscopical Society (Wolman, 1989) and also received the Pioneer Award of the International Federation of Histochemical Societies (Carpenter, 1990). In 2000, an annual Wolman lecture was inaugurated in his honor by the Israel Society for Histochemistry and Cytochemistry. He was appointed as emeritus professor of the Tel Aviv University in 1985 and despite being formally retired has remained active and a continuous source of knowledge and wisdom. His opening remarks in his Pearse Prize Lecture show the wisdom of a great scientist "... after all, our scientific work is amply rewarded by the clear moments when complex and difficult problems become simple and understandable" (Wolman, 1989).

It is hard to summarize a lifetime devoted to histochemistry and pathology in a short profile. The development of histochemistry in Israel and the enormous progress that has been made in the last decades owe a lot to the pioneering research and wisdom of Moshe Wolman. We wish Professor Wolman many more active years and look forward to the results of his continuing interest and wisdom.

Acknowledgments

I am extremely grateful to Professor Wolman for supplying background information necessary for the preparation of this historical profile and for checking the accuracy of the manuscript. I also like to thank his colleagues in the Department of Pathology, Sackler Faculty of Medicine, Tel Aviv University, Israel for all their help.