426 URIST, MACDONALD, MOSS, AND SKOOG 



as follows : A versene-soluble component, rich in galactosamine, was 

 reduced 50 per cent, and the galactosamine/glucosamine ratio was 

 changed from 3:1 in young to 1:8.1 in aged or osteoporotic subjects; 

 a versene-insoluble component, consisting of collagen and interfibril- 

 lary substance, was altered so that the hydroxyproline was relatively 

 high and the amino sugar content was relatively low; an alkali- 

 soluble component, consisting of collagen, was unremarkable; an 

 alkali-insoluble fraction, consisting of a small amount of uncharacter- 

 ized residue rich in carbohydrate, did not change with age. These 

 observations suggested that the interfibrillary mucopolysaccharide 

 gradually decreased progressively with aging and more abiaiptly with 

 osteoporosis of bone. Bertolin and Greco ( 1962 ) measured an in- 

 creased daily rate of excretion of a mucopolysaccharide with a high 

 galactosamine/glucosamine ratio in the urine of patients with osteo- 

 genesis imperfecta and osteoporosis. These observations substan- 

 tiated the findings of Sobel et al. (1954) and Sobel (1960) that the 

 rate of deposition of hexosamine-containing substances decreases in 

 the skin and bones of rats with the progress of growth and aging. 

 These changes were probably unspecific, but it would be of interest 

 to know whether they occur in osteoporosis associated with endog- 

 enous and exogenous hyperadrenal corticoidism, hyperthyroidism, 

 acromegaly, and other endocrinopathies. 



Nutrition and Metabolism of Calcium 



Though a calcium-deficiency disease has never been clearly estab- 

 lished as an entitv in adult human beings (Nicolaysen, 1960), it is 

 generally assumed that low calcium intake is one of the factors in 

 the development of osteoporosis (Malm, 1961). The hypothesis 

 rests on the observation that some patients who are in negative 

 calcium balance on 0.8 gm per dav will retain substantial amounts 

 on an intake of 2.0 gm. Nordin (1962fl) reasoned that if osteoporo- 

 sis is due to increased bone resorption, one would expect to find 

 reduced calcium intake, malabsorption, or high excretion in osteo- 

 porosis. A dietarv survev revealed that 128 patients with osteopo- 

 rosis had a significantly lower intake of calcium and protein than 

 128 patients with normal bones (Nordin, 1962/;). As many as 15 

 per cent had steatorrhea, but this disorder did not impair the ab- 



