End Products Of Protein Metabolism Research Articles

THE PRODUCTION OF BRIGHT'S DISEASE BY FEEDING HIGH PROTEIN DIETS

For nearly a century the etiology of Bright's disease has been the subject of much medical thought and investigation. But in spite of this, the clinician is still unable to find a cause for the disease in the great majority of cases seen by him. The present investigation was undertaken with the hope of throwing some additional light on this difficult subject. The chief business of the kidneys is to rid the organism of the end products of protein metabolism. This task is accomplished to a considerable extent by active secretion on the part of certain portions of the tubular epithelium. These cells will not only remove normal waste, but they will also remove from the blood stream substances which are foreign to it even though they may be severely injured by the poisons passing through them. Thus investigators 1 have shown that when the kidney eliminates such substances as mercury,

THE INTERPRETATION OF A POSITIVE NITROGEN BALANCE IN NEPHRITIS

It has been the practice of clinicians for many years to treat cases of nephritis by means of a dietetic therapy, in which the various forms of nitrogen-containing food have beeen much restricted. One of the several reasons for curtailment of protein in the dietary has been that a damaged kidney cannot readily excrete the end products of protein metabolism, as measured by the nitrogen, and that a distinctly harmful result follows such a retention. The determination of a nitrogen balance in nephritis has been considered one of the valuable tests of the ability of the kidney to eliminate this substance. In the interpretation of this procedure, three factors have been considered essential : An accurate determination of the food nitrogen. An accurate determination of the output of the nitrogen in the urine and feces. A constant intermediary nitrogenous metabolism. The first two of these demands are readily

THE AMMONIA AND UREA CONTENT OF INFANTS' STOOLS

Since bacteria, like other living cells, require a certain intake of nitrogenous material for the maintenance of the chemical structure of their protoplasm, and many of them are also able to utilize it for their energy needs, it is evident that the mediums in which they grow must contain end products of their nitrogen metabolism. Steps in the utilization of protein by bacteria are not in the gross dissimilar from those of the same process in the complex animal organism. They hydrolyze protein, so far as we know, in exactly the same manner as do the digestive ferments and are able ultimately to split off ammonia from the products of hydrolysis just as this is accomplished somewhere in the body. It is very interesting that besides ammonia another familiar end product of protein metabolism—urea—has been measured in appreciable amounts in cultures of bacteria which are normal or occasional inhabitants of

STUDIES IN RENAL FUNCTION WITH SPECIAL REFERENCE TO NON-PROTEIN NITROGEN AND SUGAR CONCENTRATION IN THE BLOOD, PHENOLSULPHONEPHTHALEIN ELIMINATION AND BLOOD PRESSURE

Until the theories of nephritis are reduced to one and until that one has been conclusively proved to be correct, continued investigations, both clinical and experimental, seem to be demanded. These studies in nephritis deal on the one hand, with the accumulation or retention in the blood of the end-products of protein metabolism and glucose concentration in the blood, and on the other hand, with the functional capacity of the kidneys in so far as the latter may be determined by the elimination of phenolsulphonephthalein. In short, the purpose of this paper is to study : The relation of protein feeding to nitrogen retention in the blood. The relation of nitrogen retention to renal function. The relation of blood-sugar, blood-pressure, phenolsulphonephthalein elimination and nitrogen retention. So far as we can ascertain, there have been no studies covering all of these phases simultaneously and the possible