P23. Serum biochemical markers of bone formation in osteoporosis

122

PZl. Differences in biochemical response to treatment between ptivational and tumour induced ostcomalacia PE Fox and TCB Stamp Department of Bone and Mineral Metabolism, Institute of Orthopaedics, Royal National Orthopaedic Hospital, Stanmore, Middlesew A 61 year old patient of Asian origin presented with classical vitamin, D deficiency osteomalacia. In addition to characteristic routine biochemistry, serum levels of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D were abnormally low and intact PTH was excessive. A dose of 1600 units vitamin D restored normocalcaemia and slowly raised serum 25-hydroxyvitamin D. However, levels of 1,25-dihydroxyvitamin D rose rapidly to exceed the normal upper limit for over six months, with raised PTH levels persisting for a similar period. A 59 year old female with an eight year history of hypophosphataemic osteomalacia was subsequently shown to have a tumour of the perineum which was incompletely resected. Histology revealed a hemangiopericytoma. Biochemical investigations showed hypophosphataemia associated with normocalcaemia and a persistently low 1,25dihydroxyvitamin D despite normal PTH and 25-hydroxyvitamin D levels. Massive phosphate supplementation lowered serum calcium within normal boundaries, PTH rose to abnormally high levels but no change in 1,25-dihydroxyvitamin D ensued. The addition of calcitriol restored normal 1,25dihydroxyvitamin D levels and steadily healed the disease but did not affect serum phosphorus concentrations. Tumour resection, even though incomplete rapidly restored normophosphataemia: 1,25_dihydroxyvitamin D levels rose further but remained within the normal range. The above results underline basic differences in vitamin D metabolism and endocrinology in the two differing forms of osteomalacia.

P22. Urinary hydroxypyridinium crosslinks and rates of change of bone mass in patients with primary hyperparathyroidism PA Mole, SP Robins’, MH Walkinshaw and CR Paterson Department of Biochemicnl Medicine, Ninewlls Hospital and Medical School, Dundee, DDl 9SY and *Biochemical Sciences Division, Rowett Research Institute, Aberdeen, AB2 9SB Urinary concentrations of the collagen crosslinks, pyridinoline and deoxy-pyridinoline, were determined in 21 patients with untreated primary hyperparathyroidism The rate of change of bone mineral content of the distal forearm of I2 of the patients was measured using single photon absorptiometry over a mean period of 2.65 years. Although mean urinary excretion of both pyridinoline and deoxypyridinoline was elevated compared with normal subjects, there was no correlation with either bone mineral content (BMC) or z score for BMC of the distal forearm However we found a significant positive correlation of both urinary pyridinoline [rK=O.55,pO.5; rK=-0.29,p>O.l respectively]. Our findings may reflect a high turnover in the trabecular bone of the distal forearm. Abnormalities in pyridinium excretion occurred in38% (for pyridinoline ) and 50% (for deoxypyridinoline) of patients with primary hyperparathyroidism compared with only 29% who had alkaline phosphatase. of their serum abnormalities Measurements of urinary pyridium crosslinks may be useful in patients with primary evaluation of the clinical hyperparathyroidism.

Abstracts

from the Joint Meeting, September

1992

P23. Serum biochemical markers of bone formation in oateopomeia F Li, W Wassif , P Fottrell, R Sherwood, P Pi@, H Berry*, M Buxton-Thomas** and C. Moniz Departments of Clinical Biochemistry, ‘Rheumatology and “Nuclear Medicine, King College Hospital and Deptartment of Biochemistry, University of Galway, Ireland Three markers of osteoblast activity, alkaline phosphatase (ALP), bone-gla protein (BGP) and procollagen I carboxy-terminal peptide (PICP) were measured in serum samples from 289 postmenopausal female patients whose spinal bone mineral density (BMD) was greater than 1SD below the mean for agematched controls. Patients were seen in the Osteoporosis Clinic and none had clinical or biochemical evidence of osteomalacia. Patients were further subdivided according to menopausal age into those receiving no treatment, on steroids for a variety of conditions or after renal or liver transplants. ALP showed the expected age-related increase, which was matched by PICP but not BGP. Those on steroids had reduced levels of ALP and BGP but not PICP, compared to untreated postmenopausal women. Over a year of treatment with antiresorptive agents PICP fell, whereas ALP increased and BGP remained unchanged. Additionally the temporal pattern of change of these markers with treatment, differed. There was a significant correlation (Spearman) between ALP, PICP and BGP and the first two only with BMD of the spine suggesting that these are useful markers of bone formation, but possibly reflecting different functions of the osteoblast.

P24. Bone n&era1 density in Tumefs syndrome NJ Shaw, VK Rehan, CS Smith and C Sausmann Institute of Child Health, Alder Hey Children’s Woman’s Hospital, Liverpool

Hospital

nnd

Osteoporosis is a recognised feature of Turner’s syndrome the actiology of which is unclear. This study aimed to determine the prevalence of reduced bone mineral density in children with Tuner’s syndrome. 17 girls (age 4-17 years) had the bone mineral density of their lumbar spine determined by dual energy X-ray absorptiometry (DEXA) comparison being made with normal healthy controls. Nine were on treatment with oestrogen and 11 with growth hormone. Their height standard deviation score (SDS) ranged from -1.41 to -5.26. The bone density SDS ranged from 0.92 to -2.21 with 10 individuals having values below the mean but only 2 were more than 2SDs below the mean. When matched for weight and pubertal status rather than chronological age only 2 individuals had results below the mean. There was a significant correlation (r=0.56 p=O.O2) between the bone mineral density SDS and the height SDS. No significant differences in bone mineral density were seen between those receiving wstrogen and/or growth hormone and those on no treatment. These results suggest that the reduction in bone mineral density in children with Turner’s syndrome is predominantly due to body size and is less significant than previously thought.

P25. Pamidronate - a definitive treatment neuroarthropathy? PL Selby, MJ Young and AJM BouIton of Medicine, Manchester Department Manchester, Ml3 9WL

for diabetic

Royal

Charcot

Infirmary,

Charcot neuroarthropathy is one of the most devastating complications of diabetes, leading to much deformity and frequently to amputation. As yet no therapy which modulates the bone destruction has been described. Impressed by the similarity of the bone changes to those of reflex sympathetic