The urinary excretion of collagen degradation products by quadriplegic patients and during weightlessness.

Urinary total hydroxyproline, peptide-bound hydroxyproline, hydroxylysine glycosides, and calcium were measured in three healthy individuals subjected to weightlessness for eighty-four days and in three young quadriplegic patients. The former group had significant calciuria but no evidence of collagen degradation. The latter group, however, had conspicuous calciuria and also excreted large amounts of collagen breakdown products. This documented degradation of matrix may be related to the continuous calciuria, osteoporosis, and cutaneous dystrophic changes occurring in quadriplegics.