Urinary hydroxyproline in multiple myeloma: correlation with clinical stages and bone disease.

Twenty-four-hour urinary hydroxyproline excretion (HOP) (normal values: 6-22 mg/day/m2) was measured by the Hypronosticon test in 50 untreated patients with plasma cell myeloma. At diagnosis, HOP was elevated in 36 of 50 patients (72%) with a mean value of 35.9 mg/day/m2. Extent of bone lesions and clinical stage were accurately assessed in all patients. Higher HOP values were found in patients with a higher degree of bone lesions (multiple lytic areas and/or destruction of skeletal segments). According to clinical stages, HOP was very elevated only in stage III (mean value: 43.7); in stages I and II the mean value (25.2) was just above the normal range. Our data indicate that HOP in multiple myeloma at diagnosis is closely related to the extension of skeletal lesions and that during the clinical course it may be useful in the follow-up of bone disease.

[Findings on total hydroxyproline excretion in patients with scoliosis]. / Indagini sull'escrezione di idrossiprolina totale in pazienti affetti da scoliosi

Variations in the metabolism of collagen of patients with idiopathic scoliosis were studied by measuring the quantity of total hydroxyproline excreted in the urine in 24 hours. Results were correlated with the degree of deviation and the degree of rapid vertebral growth. From the results a hypothesis can be formulated that scoliosis is caused by altered metabolism of connective tissue with increased destruction of collagen demonstrated by the increased excretion of urinary hydroxyproline.