Gout, with a section on ocular disease in the gouty

by Llewellyn J. Llewellyn

But when we pass to the realm of their symptomatology, resemblance, if it does not cease, becomes relatively obscured. Cystinuria and pentosuria appear to be “harmless anomalies,” and the same is true of alkaptonuria. The cystinuric, albeit, does suffer with urinary concretions, and we may recall that some authorities hold that gout and uric acid calculi are not unrelated. As to alkaptonuria, it has this attenuated link with gout that in its later stages the victims thereof tend to develop a degenerative type of arthritis, while the frequently associated pigmentary change, ochronosis, has a predilection for deposition in the cartilages of the ears and joints.

But how colourless the clinical features of alkaptonuria, etc., as contrasted with the vivid arresting phenomena of gout! how remote the latter disorder from these “harmless anomalies”!

Apart from this general distinction, before gout could with justice be relegated to the same category of disorders, it would be necessary to prove that uric acid was an intermediary and not a terminal product of metabolism. All modern research, however, tends to indicate that uric acid is an end-product, and, moreover, that there are no uricolytic ferments within the body whereby its destruction can be accomplished. The term “chemical malformation,” therefore, though strictly applicable to alkaptonuria, cystinuria, etc., is inapplicable to gout. In other words, though, for example, the homogentisic acid met with in alkaptonuria is a “chemical malformation,” uric acid cannot be regarded as such. We see, therefore, that though gout may, superficially regarded, appear to have kinship with alkaptonuria and its congeners, yet in reality there is a profound and essential difference between it and this fascinating group of disorders.

CHAPTER VI
NUCLEIN METABOLISM

No hard and fast line can be drawn between the metabolism of protein and that of nuclein. For though, morphologically speaking, the nuclei of cells are sharply differentiated from the circumambient cytoplasm, and exhibit equally distinct staining reactions, yet, chemically, the differences between them are quantitative rather than qualitative.

But while, as far as chemical changes are concerned, nuclein metabolism is comparable with that of protein, nevertheless the former in respect of its “energy” and its bearing upon growth and production, is infinitely more vital, incomparably more active; for it is in nuclear changes that we may best discern evidence of the initiation of oxidation processes and other varieties of enzymatic activity. Moreover, as Walker Hall points out, “the presence of masked iron phosphorus and certain forms of fat in the cell nucleus strengthens this view, and thus we are led to recognise the important part played by the nucleus in the life of the cell, and to appreciate the influence of nuclein heredity in cellular exchanges.”

So much by way of prelude, but the story of the growth of our knowledge of nuclein as opposed to protein is so fascinating as to be worthy of a slight digression.

The Isolation of Nucleic Acid

Functionally regarded, the nucleus is the essential element of the cell. Embedded within the cytoplasm, its isolation therefrom, and this in quantities sufficient for analysis, may well have dismayed the earlier workers. But the resources of Friedrich Miescher were equal thereto. Treating surgical bandages soaked with pus with a dilute solution of sodium sulphate, he extracted the heavy pus cells. These, then, by careful decantation, were easily disengaged. The pus cells, still intact, were then subjected to the digestive action of artificial gastric juice. The protoplasm was thus dissolved, but not the more resistant nuclei, which remained as an insoluble grey powder. In this manner cell nuclei, free from protoplasm, became available for chemical analysis. Treating the insoluble nuclei thus obtained with dilute sodium carbonate, a solution was formed. Acetic acid added thereto produced a flocculent precipitate which was found to contain phosphorus, and responded to protein colour tests. This substance Miescher christened by the name of nuclein. Subsequent observers prepared nuclein from the nuclei of yeast cells and the red blood corpuscles of birds. All nucleins are insoluble acids which form soluble salts with sodium. But while they respond to protein colour reactions they differ from protein in that they contain phosphorus and resist the solvent action of artificial gastric juice.