patients with CRF, being 2-35 (±1-41), 3-97 (±1·15) and 8-01. (+2-7) ng/ml in the three groups, compared with control values of less than 1 ng/ml. Thus in ...
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Medical Research Society
patients with CRF, being 2-35 (±1-41), 3-97 (±1·15) and 8-01 (+2-7) ng/ml in the three groups, compared with control values of less than 1 ng/ml. Thus in patients with declining renal function there is progressive elevation of basal plasma cyclic AMP con centrations. There is also impairment of the response to PTH which may be attributed to loss of functioning renal tissue. However, at the same time there is increasing secondary hyper parathyroidism which might itself lead to resistance at the receptor site. 92. A PROSPECTIVE STUDY OF SOME POSSIBLE AETIOLOGICAL FACTORS IN FRACTURED NECK OF FEMUR R. WOOTTON, P. J. BRERETON, M. B. CLARK 1 , R. H E S P , H. HODKINSON, L. KLENERMAN, G. LOEWI, J. REEVE and TELLEZ-YUDILEVICH
M. M.
Northwick Park Hospital and MRC Clinical Research Centre. Harrow, Middlesex, and ' Massachusetts General Hospital, Massachusetts, U.S.A. A prospective study of patients with fractured neck of femur was carried out over a 12 month period to investigate the role of some recently suggested aetiological factors predisposing to this condition. 89 fracture patients, studied between 1 and 3 weeks after hip-joint replacement, were compared with 73 patients admitted for non-acute orthopaedic procedures. Transiliac bone biopsies were taken from hip fracture patients at the time of operation, and the following parameters were measured in both groups in addition to routine biochemical and haematological investigations: radio-calcium absorption and 24 h space, serum 25(OH)D concentration, glomerular filtration rate (GFR) using "Cr-EDTA and forearm densitometry. Extended dietary histories were also taken from each patient. There were no significant differences between the two groups in albumin-corrected plasma calcium concentration or alkaline phosphatase activity, nor in radiocalcium absorption, in 24 h ■"Ca space, or in estimated dietary intakes of calcium and vitamin D. Relative reductions, none of more than borderline statistical significance, were observed in the fracture group for history of exposure to sunlight, plasma phosphate con centration, serum 25(OH)D concentration and the bone mineral density of the radius. It did not prove possible to exactly match the fracture group (mean age 80, SD 9-0 years) for age with the controls (mean age 70, SD 7-2 years) and the age difference may explain in part the considerable differences in GFR between the two groups (fractures 56 + 28, controls 71 ± 25 ml/min; mean and SD). We have not been able to detect gross abnormalities of mineral metabolism in the fractured-neck-of-femur population as a whole, nor in any sub-population. Only one patient had florid osteomalacia as judged histologically by an elevated number of bright lines (>3) on polarized light microscopy and another patient had hyperparathyroidism. However, we have been able to confirm that serum 25(OH)D concentrations in elderly hospital inpatients in London are low (log-transformed mean value in controls = 8-6; in fractures 6-4 /ig/ml) by standards pertaining in other temperate countries.
93. CHOLECALCIFEROL ABSORPTION IN THE EL DERLY J. M. BARRAGRY, M. W. FRANCE, D. CORLESS, S. P. GUPTA, S. SWITALA, B. J. BOUCHER and R. D. COHEN
Unit of Metabolism and Endocrinology and Department of Clinical Chemistry, The London Hospital and Medical College, Department of Geriatric Medicine, The Eastern, Hackney, and St Bartholomew's Hospitals, London Elderly females, especially those in long-stay wards, often have low plasma levels of 25(OH)D 3 and may have radiological or
histologicat evidence of osteomalacia. Osteoporosis also com monly occurs in elderly females and there is some evidence that vitamin D deficiency also contributes to the development of this condition. Neither a deficient diet nor inadequate exposure to sunlight necessarily account for the low plasma 25(OH)D 3 levels found in elderly subjects. The possibility that intestinal malabsorption of dietary vitamin D might occur in the elderly was therefore investigated. [ 1,2-3HlCholecalciferol was administered orally with a 30 g lipid meal to 15 control subjects (mean plasma 25(OH)D 3 = 102 + SE 16-5 nmol/1), to five subjects known to have a malabsorption syndrome and to 20 female subjects from a longstay geriatric ward (mean plasma 25(OH)D 3 = 10-88 + SE 2-95 nmol/1). Blood samples drawn hourly for 6 h were subjected to a lipid extraction procedure and PHlcholecalciferol was separated from its more polar metabolites using silica-gel column chromatography. The plasma triglyceride response to the ingestion of lipid was estimated and used as an index of intestinal transit time in control and geriatric subjects. Within the control group the plasma PHlcholecalciferol and 3 H-labelled polar metabolite responses were somewhat greater in the female than in the male subjects. In the malabsorption group the plasma PHlcholecalciferol and 3H-labelled polar metabolite responses were substantially lower than those of the control group (P < 0-01 and P < 0-05 respectively). In the geriatric group the plasma PHlcholecalciferol and 3H-labelled polar metabolite responses were also lower than the (female) control group (P < 0-01). Of the total 3 H radioactivity present in the plasma the percentage of radioactivity associated with polar metabolites of cholecalciferol was similar in all three groups of subjects. The time course of the rise in plasma triglycerides after the lipid meal containing the label was similar in both the control and geriatric subjects with a peak response at 3 h. It is inferred that neither an impairment of intestinal motility nor increased removal of absorbed PHlcholecalciferol by con version into more polar metabolites can account for the reduced plasma response to PHlcholecalciferol administration and these findings support the suggestion that malabsorption of dietary cholecalciferol may occur in the elderly.·
94. ASSESSMENT OF THE FUNCTIONAL EFFECTIVE NESS OF ANTIBODY PRODUCTION DURING LONGTERM SALMON CALCITONIN THERAPY D. J. HOSKING, L. B. DENTON, B. CADGE and T. J. MARTIN
Department of Medicine, General Hospital, Nottingham, Harlow Wood Orthopaedic Hospital, Mansfield and Department of Chemical Pathology, University of Sheffield, Sheffield Although calcitonin may be very effective in relieving bone pain in Paget's disease bone turnover is not always controlled. It has been suggested that antibody production to the exogenous (salmon or porcine) calcitonin is responsible. In order to test this hypothesis 20 previously untreated patients with Paget's disease were challenged with calcitonin before and after 6 months continuous salmon calcitonin therapy. If antibody production exerted a functionally significant effect the acute hypocalcaemic response to calcitonin should be diminished or abolished. However, this response is also affected by the prevailing rate of bone turnover. The influence of therapeutically achieved reductions in disease activity were assessed by challenging the patients with porcine calcitonin (PCT) given only on two test occasions and to which antibody production was therefore remote. In the light of these findings the acute hypocalcaemic response to SCT could be assessed. When the patients were compared before and after 6 months SCT therapy the linear relationship between acute hypocal caemic response and bone turnover was unaltered. Antibodies to SCT developed in eight of the 20 patients but did not appear to modify the acute hypocalcaemic response to either type of calcitonin. Furthermore there was no significant difference between the hypocalcaemic response of those patients who
