[Clinical evaluation of the results of the Sr85 test and of bone alkaline phosphatase isoenzyme activity].

Coinciding investigations of the 85Sr test and of bone derived serum alkaline phosphatases activity were undertaken in 38 patinets with locomotor system diseases. In 15 patients there was congruence between the positive result of the 85Sr test and an increased activity of B-ALP. In 5 patients there was congruence between negative outcome of B-ALP and negative 85Sr test. The activities of T-ALP, B-ALP, L-ALP and I-ALP were compared with a group of 124 healthy controls. The causes of 18 incongruent results were analysed. In rhizomelic form of ASp, active Paget's disease, osteomalacia and in some forms of osteoporosis there was congruence between increased activity of B-ALP and the positive 85Sr test over the clinically involved area of the locomotor system. In ankylosing spondylitis (without rhizomelic involvement) there may be a moderate fall of B-ALP activity but the 85Sr test is usually positive; this may correspond with metabolic activity in the paravertebral region of the ligaments. Low B-ALP activity and positive 85Sr test in MP may refer to a latent process in the bone apparatus without marked activity of osteoblasts. The fall of B-ALP may be a result of therapy or due to the reduced capacity of B-ALP to be released from the bone. In osteomalacia the rapid fall of 85Sr activity during the test is the cause by the presence of pathological osteoid which may be, even in patients with hypertension, of renal origin. A method was described permitting the evaluation of the process of active incorporation of bone minerals (after 8 days). The activity of the 85Sr test over clinically silent areas (e.g. spine) may indicate a decompensated process in the spine due to an involvement to the large joints. The two methods used in this study are metabolically different (85Sr binds to proteoglycans and inorganic structures of bone tissue, alkaline phosphatase to the activity of osteoblasts) and prove to be clinically valuable. Detailed analysis of the results makes it possible to define the stages of clinical activity of disease and to check more exactly the efficiency of the therapeutic method.