Nephrol Dial Transplant (1996) 11: 1958-1960

Special Feature

NephrologyDialysis

Transplantation

Sandor Koranyi (1866-1944)

Sandor Koranyi was a distinguished Hungarian physi-ologist and clinician who opened the door to studiesof kidney function in renal disease. In this respect hewas a pioneer of the modern era of clinical nephrology.For various reasons his work has largely been forgottentoday. On an annual basis, the Hungarian Society ofNephrology awards a Koranyi Prize and the SandorKoranyi Society awards a Koranyi Memorial Medalwith an accompanying lecture. This brief review intro-duces the life and work of Sandor Koranyi to the non-Hungarian nephrological community. It emphasizeshis two main contributions to modern nephrology, i.e.the introduction of physicochemical methods into theanalysis of renal function, and the provision of arational basis for dietary treatment of renal disease.

His life

Sandor Koranyi was born in Budapest in 1866. Hisfather, Frigyes Koranyi, was a renowned professor incharge of the First Internal Clinic in Budapest. SandorKoranyi started as a student of anatomy (1884-1885)and subsequently pathology (1887-1888). He immedi-

ately showed his talent by publishing three papers andpresenting one of them to the Hungarian Academy ofSciences (15 June 1885). He obtained his medicaldiploma in 1898 and turned to Strasbourg, then oneof the leading German universities, to start a career inthe Department of Physiology (under Professor Goltz).He was introduced into the methodology of experi-mental medicine and collaborated with, and became afriend of, Jacques Loeb. In August 1889 SandorKoranyi returned to Budapest. He was first resident inthe clinic of his father and was appointed as assistantto the professor in 1895. His interest in physiologyprompted him to lecture on physiology, physics andhistology at the veterinary college, where he thenbecame a lecturer and submitted a thesis on the subject'Experimental and practical pathology and therapy ofthe nervous system'. In 1900 he was made HonoraryProfessor of Neurology and was promoted to fullProfessor in Internal Medicine in 1907. He had only asmall clinic with two wards, but had a laboratory inwhich his ground-breaking scientific studies were per-formed. After the retirement of his father, he wasappointed Professor of Internal Medicine at the ThirdClinic of Internal Medicine in Budapest.

Major scientific contributions in nephrology

His major achievement was that he tried to applyphysico-chemical methods to practical clinical and toresearch problems in an effort to understand renaldisease from their repercussions on excretory renalfunction. This line of research led him to the conceptof renal insufficiency. He was convinced that changesin renal function influenced the disease process (aconcept with a modern ring in the age of progressionresearch).

Functional studies on healthy and pathological kidneys

It all started with an anecdotal observation. During agynaecological operation in 1890 the ureter of a patientwas damaged. The surgeon stitched the ureteral stubto the abdominal wall and asked Koranyi to determinewhether the kidney was healthy or whether it could besafely removed. Koranyi performed detailed studies onthe function of both kidneys. The function of thekidney with the intact ureter proved to be normal,while tests on urine from the ureter stitched to theabdominal wall indicated impaired function, i.e.decreased sodium, chloride, phosphate and urea con-centrations. Consequently, the kidney was removed

1996 European Renal Association European Dialysis and Transplant Association

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Sandor Koranyi (1866-1944)

and histology showed marked sclerosis [1]. Thisunusual case prompted a series of studies on renalfunction which culminated in the concept of renalinsufficiency. The use of ureteral diversion was intro-duced, half a century later, as a model to studyexperimental renal disease [2].

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changes from -0.56°C to -0.6°C. He ascribed thisincrease to organic decomposition products which hecalled 'residual nitrogen'. This work was appreciatedby Volhard, who wrote in 1942 'the main result oflasting value is the recognition that variability of renalfunction is lost in renal failure' [3].

Introduction of the freezing point method

Sandor Koranyi applied the method of cryoscopy, i.e.determination of freezing point depression, to studieson concentrating and diluting capacity of the kidneyin order to evaluate renal function. Cryoscopy waslater replaced by gravimetry.

Cryoscopy was first applied to serum and urine ofnormal individuals. The freezing point depression ofurine was found to vary between — 0.45°Cand — 2.4°C.Koranyi then applied this method to serum and urineof nephritic patients. A breakthrough was his recogni-tion that while the healthy kidney is capable ofadapting freezing point depression over a wide rangeaccording to needs, the ability of the nephritic patientto do so is limited. The difference between maximumand minimum freezing point depression became pro-gressively less with advancing renal dysfunction.

He proceded to show that osmotic pressure in theblood of highly evolved animals is constant. He showedthat in nephritic patients, independent of the cause ofrenal disease and renal morphology, the capacity ofthe kidney is reduced to modulate freezing pointdepression in accordance with salt and water load. Toa certain extent this defect was compensated bypolyuria.

Stages of renal insufficiency and their relation toreduced renal function

Koranyi introduced the term 'renal insufficiency' in1896: 'If the organism is unable to compensate, a stateensues when demands of the organism cannot be metany more.' He stated that in healthy individuals dailyurinary excretion exceeds the potential minimum urinevolume, suggesting the presence of a 'safety reserve'.He argued that if kidneys lose reserve capacity, thefunction can be maintained by recruiting compensatingmechanisms, so that a new balanced steady stateensues. Sixty years before this subject raised widespreadinterest, Koranyi recognized the importance of residualparenchymal function for the progression of renaldisease.

He observed that in advanced renal failure, freezingpoint depression of blood and urine approached eachother, suggesting limitation of the osmotic function ofthe kidney. The adapting capacity of the kidneyappeared to cease, i.e. freezing point depression ofblood and urine did not change following loads ofwater, saline or nitrogen. This state was later calledisostenuria by Volhard.

Koranyi recognized that in the advanced stage ofrenal insufficiency, retention of nitrogenous productsis characteristic and freezing point depression of blood

Dietary treatment of renal insufficiency

Koranyi tried to translate these insights into practicaladvice for the treatment of renal patients. He proposedthat the diet should be tailored to the capacity of thekidney: 'We would greatly ease the life of patients ifwe could adapt the diet in such a way that the numberof dissolved molecules released through metabolismdoes not exceed the capacity of the kidney to dischargemolecules.' The results and observations of thisapproach were published in a monographyTunktionelle Pathologie und Therapie derNierenkrankheiten' [Functional Pathology andTherapy of Renal Disease] [4].

To do full justice to his scientific oeuvre, it must bementioned that his investigations were not only limitedto renal disease. He also worked on such diverse topicsas oedema formation (as recently reviewed by Richet[5]), digitalis therapy in heart disease, pathogenesis ofarrhythmias, relationship of high blood pressure tocardiac disturbances, treatment of typhoid fever andtuberculosis. He even proposed the concept of cyto-static treatment in malignant haematological diseases.He also recognized the importance of statistical evalu-ation of therapeutic results and published on this issue.

As a representative of the Medical Faculty of theUniversity of Budapest he was member of the UpperHouse of Parliament. He castigated the shortcomingsof Hungarian medical science, medical care and med-ical training. He called for improvement, with somesuccess. He was member of the Hungarian Academyof Sciences, but his scientific merits were also acknow-ledged on an international level. He was honorarymember of the Academia Leopoldina (DeutscheNaturforscher) and of the Interstate PostgraduateMedical Association of North America. He retired in1936 at age 70. The last years of his life were cloudedby myocardial infarction and stroke. He died on12 April 1994. He is rightly considered the Nestor ofHungarian nephrology.

Prof. S. SonkodiAlbert Szent-Gydrgyi Medical University

Szeged, Hungary

Acknowledgement. The assistance of Prof. E. Ritz in preparation ofthis article is gratefully received.

References

1. Koranyi A. Funklionelle Pathologie und Therapie derNierenkrankheiten. Berlin: 1929

2. Masaki Z, Ferrario CM, Bumpus FM. Cutaneous tubelessureterostomy as a procedure to study renal function in consciousdogs. Invest Urol 1978; 16: 224-228

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3. Volhard F. Nierenkrankungen und Hochdruck. Leipzig: 19424 Springer 19295. Richet G. Edema and uremia from 1827 to 1905: the first faltering

steps of renal pathophysiology. Kidney Int 1993; 43: 1385-13066. Koranyi S. (with coauthor Jacques Loeb). Ober den Einfluss der

Schweerkraft auf den zeitlichen Verlauf der geradlinigenWilkurbewegung unseren Armes, PflUg Arch Ges Physiol 1889;46: 101

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7. Koranyi S. (with coauthor Jacques Loeb). Ober Storungen dercompensatonschen und spontanen Bewegungen nach Verletzungdes Grosshirns. PflUg Arch Ges Physiol 1891; 48: 423

8. Koranyi S. Physikalisch-chemische Methoden undGesichtspunkte in ihrer Anwendung auf die pathologischePhysiologje des Kreislaufes, Z Physiol 1897

9. Koranyi S. Vom diagnostischen Werte der Niereninsuffizienz aufGrund klinischen Erfahrungen. Ung. Med. Presse, 1898; 13

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