Angela Fairney

Studies on the measurement of 25-hydroxy vitamin D in human saliva

A competitive protein-binding assay for 25-hydroxy vitamin D (25-OHD) in saliva has been established by adaptation of that previously described for 25-OHD in serum (Fairney et al. 1979). Random values of salivary 25-OHD in patients attending hospital for venesection showed a wide range of results (105-1000 pg/ml, n 55). These values corresponded to 1.2% of the total serum values with which they showed a significant relation (r 0.45, P less than 0.001). There was no relation between salivary 25-OHD and measured serum free 25-OHD in eighteen pairs of saliva and serum studied. Studies in two individuals showed that salivary 25-OHD values varied throughout the day and that a vitamin D load (19.5 micrograms), given as pickled herrings at lunch, produced a marked rise in 25-OHD values 5-8 h later. Diurnal profile studies of salivary 25-OHD in Caucasian and Asian 11-year-old male schoolchildren showed lower values in Asian children eating a vegetarian diet, and a significant variation with time and ethnic group (P less than 0.001). It is concluded that 25-OHD is present in saliva and that the values vary throughout the day. The values obtained may relate to dietary intake of vitamin D and the subjects ethnic origin.

Calcium metabolism following renal transplantation

Abnormalities of calcium homeostasis are a recognized feature of end-stage renal disease. The treatment of choice is renal transplantation, but this does not always result in normalization of the biochemical profile. Persistent hypercalcaemia is well documented and our study was undertaken to investigate the status of the calcium regulating hormones in renal patients post-transplantation. Serum calcium, parathyroid hormone, 1,25-dihydroxyvitamin D (1,25(OH)2D) and osteocalcin concentrations were measured in post-transplant patients. Twenty per cent of the patients had subnormal 1,25(OH)2D concentrations while 55% had biochemical evidence of hyperparathyroidism but only 5% were hypercalcaemic. Time elapsed since transplantation was not correlated with any of the analytes investigated and there was no relationship between persistent impairment of renal function and abnormalities of calcium homeostasis.

Vitamin D deficiency masking primary hyperparathyroidism

Vitamin D deficiency and primary hyperparathyroidism (PHPT) are relatively common disorders. The coexistence of these conditions should be considered, as depletion of vitamin D may alter the clinical expression of autonomous parathyroid disease. We report details of a vitamin D deficient patient in whom replacement therapy led to the unmasking of occult PHPT.

Response to alendronate in osteoporosis after previous treatment with etidronate.

Abstract: Bisphosphonates such as etidronate and alendronate are widely accepted as effective agents for the treatment of osteoporosis. However, some physicians find the choice of which one to use in different patients, and the comparative magnitude of response, unclear. Fifty postmenopausal women with osteoporosis [group 1: 27 women who had received 3 years of previous cyclical etidronate treatment, mean age 70.5 years, bone mineral density (BMD) mean T-score lumbar spine (LS) −3.58 and femoral neck (FN) −2.51; group 2: 23 women who had not previously received cyclical etidronate treatment, mean age 73.7 years, BMD mean T-score LS −3.65 and FN −2.96] were treated with 10 mg alendronate daily, to determine whether pretreatment with etidronate affected the response to alendronate, and whether patients who did not respond to etidronate, responded to alendronate. There was a significant increase in LS BMD after 2 years of treatment with alendronate compared with baseline (group 1: 7.84%, p<0.001; group 2: 6.69%, p<0.001), but there was no statistical difference between the groups. In the group 1 patients there was a significant difference between the initial response (at the LS BMD) to 2 years of cyclical etidronate (1.86%) and later response to 2 years of alendronate (7.84%) (p<0.0001). The 10 patients who did not respond at the LS to etidronate alone, showed a significantly better response (mean BMD change +6.3%) when subsequently treated with alendronate (a net difference of 9.3%, p = 0.002). In 15 patients who did not respond at the FN to etidronate alone, the mean response to alendronate was +0.96% (a difference of 7%, p = 0.004). This study shows that pretreatment with 3 years of cyclical etidronate is not detrimental to the subsequent LS BMD response to alendronate. There is evidence that alendronate produced a greater bone density response than etidronate, and patients who did not respond to etidronate with an increase in LS bone density, subsequently did so following alendronate.

Vitamin D metabolism in polar vertebrates

1. Studies of serum 25-hydroxy-vitamin D (25-OHD) in the Antarctic have been undertaken in husky dog, seal and penguin and compared to man. 2. Husky dogs showed a reversal of the expected seasonal variation of serum 25-OHD with maxima in June when the hours of bright sunshine and amount of u.v. -B radiation were lowest. 3. Values for random serum 25-OHD values in seals showed large interspecies differences, the values for Weddell seals being significantly greater than for Crabeater seals (P less than 0.01). 4. Penguin sera showed low concentrations of serum 25-OHD with no evidence of a response to prolonged exposure to sunlight.

A Simple Micromethod for 25-Hydroxyvitamin D Estimation

A quick and simple method for estimating 25-hydroxyvitamin D is described. It involves dichloromethane extraction followed by competitive protein-binding assay without chromatography. This assay can be performed on 100 μl of serum and enables 50 samples to be estimated in one working day. The simplicity, speed, and sample size of this method make it very suitable for use in a routine clinical biochemistry laboratory. It is particularly useful when calcium disorders secondary to abnormalities in vitamin D intake and metabolism are suspected.

The use of biochemical tests in the diagnosis of disorders of calcium metabolism.

gastric and duodenal ulcer and of pancreatitis. If hypcrcalciuria is present, renal stones or nephrocalcinosis may occur and may lead in some cases to renal failure. If bone disease is present with hyperparathyroidism (osteitis fibrosa cystica) radiography of the hands may show subperiosteal erosions. Other radiographs may show loss of the lamina dura, subcortical bone resorption, and the presence of bone cysts, especially in the jaw. Hypercalcaemia secondary to a tumour may be due to associated bony metastases which destroy bone and liberate calcium from the skeleton. The commonest tumours to do this are carcinoma of the breast and multiple myeloma. Ectopic parathyroid hormone (PTH) production, which also results in calcium release, is another possible feature of many tumours, the commonest being a squamous cell carcinoma of the lung. The milk-alkali syndrome is a rare cause of hypercalcaemia characterised by alkalosis and a history of ingestion of large quantities of milk, or alkalis, or both, as in the overtreatment of peptic ulcer. A diagnosis of multiple myeloma is suggested by osteolytic bone lesions, a paraprotein band on protein electrophoresis, abnormal immunoglobulin levels, and Bence-Jones proteinuria. Lung symptoms with fever and fatigue are features of sarcoidosis.

Glucorticoids and bone mass in asthma

DISTAL RADIUS BONE MINERAL LEVELS IN RHEUMATOID ARTHRITIS USING PERIFERAL COMPUTED TOMOGRAPHY K. Bors. C. Horvath, Z. Radnai, Ferencvaros Health Center and Ist Department of Medicine, Semmelweis University Medical School, Budapest and Rehabilitation Canter, Visegrad, Hungary Pathogenetie role of rheumatoid arthritis for osteoporesis was studied by measurement of bone mineral content (BMC, mg/cm s) of dista~ radius using periferal computed tomography (Norland-Stratec XCT-900). We investigated 40 women with rheumatoid arthritis (age: 34-79 yrs, mean duration of the disease: 11.8 yrs, 4 premenopausal and 36 postmenopausal). 23 postmenopausal and 4 premenepausal patients had a history of steroid treatment (ST+, mean duration: 7.4 yrs), while 13 women had never used steroids (ST-). The results were compared to pQCT values of 36 age-matched women. Results: TOTAL TRABEC~ CORTICAL PREM 409.1• 205.2• 575.5• POSTM ST304.0• 151.2• 451.6• ST+ 271.9• 121.7• 394.5• CONTROLS PREM 403.5• 217.5• 555.2• POSTM 337.0• 159.7• 476.6• The difference in BMC between patients and controls was significant (p: 0.02-0.004 in different bone compartments). Considering the menstrual status and steroid treatment, the onl~ significant difference was shown between postmenopausal ST+ patients and postmenopausal controls (p: 0.01-0.005). These data suggest that low bone mineral in patients with rheumatoid arthritis could be a result of steroid treatment rather than that of the disease.