When I use a word . . . : Grapes
Authors: J. Aronson
Journal: BMJ (1998)

In recent years we have all become familiar with the names of grapes commonly used in wine making: cabernet, chardonnay, Pinot, Riesling, Sauvignon, and Shiraz, for instance. Others, less well known, include catawba, haanepoot (or honeypot), Merlot, scuppernong, and zinfandel. So what about some medical grapes? 

In Latin a bunch of grapes was racemus. In 1822 Kestner isolated an acid from grapes, and Gay-Lussac called it racemic acid. Racemic acid was in all respects chemically identical to tartaric acid, except that it did not rotate polarised light, a phenomenon described by Jean-Baptiste Biot, who postulated molecular asymmetry. Later Louis Pasteur crystallised racemic acid and saw in his microscope that it contained two types of crystal, left handed and right handed; when he physically teased them apart he found that a solution of one behaved like ordinary tartaric acid, while a solution of the other rotated light in the opposite direction. Racemic acid, being a mixture of the two, was neutral to polarised light. So the term racemate was adopted to describe a mixture of equal amounts of two stereoisomers. 

The Latin word for a single grape was uva, which gives us uvea, uvula, and pyruvate. Pyruvate (Greek πρ, pur, fire) is formed by distillation of racemic acid, the acid got from grapes; in comparison lactate (Latin lac, milk) seems rather tame, but it is lactate that is formed from pyruvate when you burn up energy in your muscles. 

The uvea was originally the choroid surface of the eye (because it looked like the skin of a grape), and later the layer of pigmented cells forming the posterior covering of the iris; now it is the iris, ciliary, and choroid taken as a unit. 

The uvula at the back of the palate looks like the little grape that its name implies. But there are other uvulas around the body: the rounded elevation at the neck of the bladder (uvula vesicae) and a small rounded structure in the cerebellum between the pyramid and the nodule (uvula vermis or cerebelli). 

Inflammation of the uvula, uvulitis, is also called staphylitis, from the Greek word for a bunch of grapes, ςταφλ (staphule). From the same word we get staphyloma, an inflammatory protrusion of the cornea or sclera. And under the microscope staphylococci cluster in bunches like grapes. 

Uva and staphylos combine in the tautologous bearberry, Arctostaphylos uva–ursi (Arctostaphylos = bear + grapes; uva–ursi = grape + bear’s). Uva–ursi contains an astringent substance called arbutin and was at one time listed in the British Pharmacopoeia as a diuretic and urinary antiseptic. 

The Greeks had another word for a bunch of grapes, βϰτρυσ (botrus), from which we get the name of a fungus, Botrytis cinerea (Latin cinereus, ashen), that causes noble rot, producing the richness of certain wines, such as Sauternes and Tokay. And botryomycosis is another name for a pyogenic granuloma. 

Bagassosis, a coniosis (see BMJ 1997;315:292), is caused by the inhalation of a dry refuse formed in sugar making, from the Spanish word bagazo, the husks of grapes left after pressing. 

And there are pharmacological grapes, too, although of a different kind. The sympathomimetic alkaloid ephedrine comes from Ephedra, the sea grape, so called because it grows in clusters. 

But I’d better stop there—I’m getting too intoxicated.