'Ur-ine the know'

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May 01, 2001

The clinical investigation team comprised of our Nephrology/Urology Center at the University of Minnesota, meets daily to discuss progress that has been made, problems that need solutions and plans for the day.

Before we end our discussion, we take turns sharing "words of wisdom."

One of our favorite topics falls under the theme called "ur-ine the know," phonetically translated as "you're in the know."

To the readers of this month's Diagnote, I say, "ur-ine" store for some fascinating knowledge about the mark urine has made on the world of medicine.

Did you know that?

References to the art of diagnosing diseases of animals and man from the examination of urine can be traced back for thousands of years to the first written records of civilization.

Babylonian and Egyptian physicians began the art of uroscopy, which eventually developed into extensive and sometimes ritualistic examination of the appearance of urine collected in special bladder-shaped flasks (called urinals or urine glasses).

In those days, the physicians often did not see the patients, but only their urine. They lacked the sophisticated methods of testing urine commonly used in our era, but they were able to obtain diagnostic clues from basic observations of the physical characteristics of urine including, volume, color, turbidity, odor, sediment and even sweetness.

Although contemporary urinalysis also includes chemical analysis and microscopic examination of urine sediment, these same physical characteristics of urine are included in our diagnostic evaluation of patients today.

The Hindus of ancient times identified the disease diabetes mellitus by the name "honey urine," because they observed that black ants were attracted to sweet urine. These insects were used as a means of diagnosis of diabetes mellitus, and this is one of the oldest diagnostic tests known in the history of science.

This observation lay dormant for centuries until Thomas Willis in 1664 rediscovered the sweet taste of urine produced in association with diabetes mellitus, and thus was able to distinguish this disease from other conditions.

The Greek words "mellitus" (meaning honey and implying a sweet taste) and "insipidus" ("in" is a prefix meaning without and "sapid" means "taste") were then used to describe different types of diabetes.

Diabetes, a term derived from Greek and literally meaning "to pass through," was used to refer to conditions associated with formation of large volumes of urine. Diabetes mellitus meant that abnormal quantities of sugar were passing through the urinary tract, while diabetes insipidus meant abnormal quantities of tasteless (non-glucosuric) urine were being formed.

In past times, the old French term "pissier" was often used to describe urine. From this term "pissier" comes the English term "piss," in use as a noun and a verb before the time of the English Bible translator Wycliff (1324-1384). According to Webster's Unabridged dictionary, ants were named "pismire" because they discharged an irritant fluid thought to be urine. Wycliff used the word pismire in translating the word "ant" at Proverbs 6:6. However, the word "piss" has not been considered polite in the English language since the spread of Puritanism.

Uroscopy

As mentioned, Hippocrates (400 B.C.), the Greek father of medicine, frequently wrote about the importance of uroscopy. By the 16th century, charts had been developed describing the significance of up to 20 different colors of urine.

However, the credibility of the urinalysis became compromised when charlatans without medical training began offering their predictions based on uroscopy to the public for a substantial fee. Many of these quacks, called "pisse prophets" and "water doctors," did not hesitate to extend their predictions (called urine casting and water casting) beyond the range of medicine. In their hands, uroscopy became uromancy (the Greek suffix "mancy," refers to divination), lost scientific value and threw discredit on the observations of ethical workers in this field of study. These quacks, who often wore elaborate gowns and headdress, became the subject of a book published by Thomas Bryant in 1627.

This expose helped to inspire the first medical licensure law proposed by Thomas Linacre, founder of the College of Physicians in England, another example of how urine left its mark on the practice of medicine.

Until the 17th century, the diagnosis of disease from urine had always been based on appearance alone. The quantitative study of urine began in 1655 when Jan Baptista Van Helmont accurately determined the specific gravity of urine by weighing it in a glass vessel with a narrow neck and known to hold a certain volume of rainwater.

He then noted the dilute nature of urine excreted after ingestion of water and the concentrated nature of urine excreted after abstention from drinking and associated with fever. These observations provided the insight that led to recognition of diagnostic errors frequently associated with examination of randomly collected urine samples by uroscopists. The need to consider other factors when interpreting urine specific gravity values remains as a basic diagnostic axiom today.

Fascinating facts

Did you know that urine is a weak detergent by virtue of its urea content? This detergent property may be greatly enhanced if urine containing large quantities of urea is allowed to undergo bacterial fermentation because most of the urea is decomposed to ammonium carbonate, a moderately alkaline salt.

Urine fermented in this way has been used for thousands of years as a soap, and as an agent to tan and soften hides removed from animals.

In France, during the 17th century wealthy ladies took urine baths to beautify their skin.

Did you know that in Roman times, urine was commonly used as a mouthwash and prophylactic against dental caries? "Rectified urine," a strongly ammonical solution, was recommended in the 18th century by Pierre Fauchard, the father of dentistry, as a dentifrice and toothache remedy. Romans also used urine (the golden liquid) as a flux for soldering gold, and to remove ink stains from garments.