518 DIABETES 



Pentosuria. Pentoses are the chief carbohydrate groups of the 

 nucleoproteids, but they are also present in many vegetables and fruits. 

 Some persons seem to lack in some respects the power of utilizing pen- 

 toses, and, therefore, exhibit a chronic pentosuria, 1 while at the same 

 time they can utilize other sugars without difficulty. 2 They eliminate 

 pentose in the urine even when there is none in the food, but seem able 

 to utilize pentose taken in the food nearly as well as normal individuals. 

 According to Neuberg, the pentose found in the urine is not the same 

 as that of the nucleoproteids, and is possibly derived from the hexoses. 3 

 This condition is not associated with constitutional disturbances, and 

 must be considered as an anomaly in metabolism similar to cystinuria 

 and alkaptonuria, especially since it may occur as a family disease. 

 True diabetes may also, in certain cases, be looked upon as an hereditary 

 metabolic disorder, in view of the frequently observed occurrence of the 

 disease as a family peculiarity. Lorand * has observed that the children 

 of diabetics may show a defective power of sugar assimilation. 



Levuiosuria, in which levulose is eliminated in the urine on a diet 

 containing moderate amounts of levulose, is a rare condition. Neubauer 5 

 has collected reports of five cases in which levulose alone was present in 

 the urine, without dextrose being present. As levulose is apparently 

 converted into glycogen, which then breaks down into glucose, the fail- 

 ure of assimilation of levulose in these patients would seem to be due to 

 a failure of the conversion of levulose into glycogen. Neubauer observed 

 in his case that a definite proportion (15-17 per cent.) of the levulose 

 given by mouth was excreted in the urine, and suggests as an alternative 

 hypothesis that a certain proportion of the levulose of the food is directly 

 oxidized without formation of glycogen, and that failure of this oxida- 

 tion may be the cause of levulosuria. Mixed levulosuria and glycosuria 

 is relatively frequent, and in some cases, at least, the levulose in the 

 urine seems to have been derived from the glucose in the body and not 

 from the levulose of the food. 



Lactosuria, or excretion of milk-sugar in the urine, has rarely been 

 observed as a form of alimentary glycosuria, but is frequently observed 

 in connection with formation of milk in the mammary gland both before 

 and after parturition. 6 After resection of the mammary glands lacto- 

 suria does not occur (Moore and Parker 7 ). 



Alimentary glycosuria, following administration of small 

 quantities of glucose, does not necessarily mean that the func- 

 tion of the liver is primarily decreased ; in some cases the 



1 Literature reviewed by Neuberg, Ergebnisse der Physiol., 1904 (3, Abt. 1), 

 373; Wohlgemuth, Biochem. Centralbl., 1903 (1), 533. More recent articles 

 by Jolles, Cent. f. inn. Med., 1905 (26), 1049 ; Adler, Pfliiger's Arch., 1905 

 (110), 625; Tintemann, Zeit. klin. Med., 1905 (58), 190; Erben, Prag. med. 

 Woch., 1906 (31), 301; Blum, Zeit. klin. Med., 1906 (59), 244 ; Janeway, 

 Amer. Jour. Med. Sci., 1906 (132), 423. 



2 Pentosuria may be associated, or occur alternately, with glycosuria ; see 

 Kaplan, New York Med. Jour., 1906 (84), 233. 



5 Many unfermented fruit-juices e. r/., apple-juice contain much pentose, 

 which may cause alimentary pentosuria when taken in large amounts (v. 

 Jaksch, Cent. f. inn. Med., 1906 (27), 145). 



4 Practitioner, 1903 (71), 522. 



5 Munch, med. Woch., 1905 (52), 1525 (full literature). 



6 Full review by Porcher, " De la Lactosuria," Paris, 1906. 



7 Amer. Jour. Physiol., 1900 (4), 239. 



