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Biomedical subjects

I T Boyle

Publications and source records attributed to I T Boyle.

At least 91 records · Page 5Linked to original sources

Hypercalcaemic osteomalacia due to aluminium toxicity.

In 16 patients with chronic renal failure and osteomalacia resistant to vitamin-D therapy, aluminium was demonstrated in bone biopsy specimens at the interface between thickened osteoid and calcified bone by means of both X-ray microanalysis and a specific histochemical stain. 14 patients also had hypercalcemia. It is suggested that this is due to the blocking by aluminium of additional calcium uptake into bone coupled with the availability of additional calcium from dialysis fluid and vitamin-D therapy. This study provides more aetiological evidence linking aluminium and the development of osteomalacia in chronic renal failure. Further, if hypercalcaemia develops in such patients it is important that aluminium toxicity be excluded as the cause to prevent unnecessary parathyroidectomy.

Adolescent↗

Hypercalcaemia and metastatic bone disease: is there a causal link?

The relation between serum calcium and the extent of metastatic bone disease as judged by radionuclide bone scan was examined in a consecutive series of 195 patients with malignant disease. Of 87 patients with hypercalcaemia, 40% had no evidence of skeletal metastatic bone disease and serum calcium values. Of 160 patients judged to have bone-scan evidence of metastatic skeletal involvement, only 32.5% were significantly hypercalcaemic. Further, a negative correlation was found between the extent of metastatic bone disease and serum calcium value. The development of hypercalcaemia in malignancy is not directly related to the presence or extent of metastatic bone disease. It is suggested that the development of hypercalcaemia may depend on an alternative mechanism, such as the production of a humoral substance by tumour tissue, having its effect on calcium metabolism at sites or organs distant from local areas of tumor involvement.

Bone Neoplasms↗

Do anticonvulsant drugs commonly induce osteomalacia?

Twenty adult epileptic out-patients who had received anticonvulsant therapy for a mean duration of 15 years were assessed for clinical, biochemical, radioisotopic and bone biopsy evidence of osteomalacia. Occasional biochemical abnormalities were demonstrated but no individual subject was found to have osteomalacia. There is increasing evidence to cast doubt on the existence of a strong relationship between anticonvulsant drugs and osteomalacia. This evidence is reviewed and it is concluded that in the presence of adequate sunlight exposure anticonvulsant therapy alone is most unlikely to lead to osteomalacia in adults.

Adult↗

The role of bone scanning in Paget's disease.

In Paget's disease, the bone scan allows visualisation of the whole skeleton, permitting accurate assessment of disease extent. The scan appearances are usually characteristic, and as uptake of tracer depends upon skeletal metabolic activity, this study reflects the severity of Paget's disease, in addition to providing early appreciation of alterations in disease activity. While correlation of x-rays and bone scans in Paget's disease have shown that neither method alone detects all lesions, it is clear that the bone scan is the more sensitive technique. In addition, those sites that are occasionally missed by bone scan are metabolically inactive. The bone scan is the investigation of choice in Paget's disease, and radiology should be used to provide supplementary information, as and when required.

Bone and Bones↗

Pseudohypoparathyroidism presenting as severe Parkinsonism.

A case of pseudohypoparathyroidism in a middle-aged female presenting with severe Parkinsonism is reported. Correction of serum calcium led to marked clinical improvement suggesting that symptoms and signs were exacerbated by hypocalcaemia and tetanic spasm. Calcification of the basal ganglia was not detected on skull X-ray but was revealed by computerized axial tomography.

Brain Diseases↗

Quantitation and localisation of aluminum in human cancellous bone in renal osteodystrophy.

There is increasing evidence that aluminium toxicity may be responsible for a type of vitamin D-resistant osteomalacia and an unusually severe form of dementia ("dialysis dementia") occurring in some patients with chronic renal failure on regular haemodialysis. High concentrations of Al have been found in blood, bone and brain tissue from these patients. The A1 comes either from the water used during dialysis (added in some public water supplies during purification to precipitate contaminants) or from aluminium salts taken orally to bind phosphates and so restrict their dietary adsorption. Recent X-ray microanalytical studies have demonstrated Al in lysosomes of cerebral cells and at the calcification front in bone of patients dying of dialysis dementia but its concentration at this site in bone has not been measured using this technique. We have examined transiliac bone biopsies from 3 patients with dialysis dementia and 6 non-demented patients on regular haemodialysis, Atomic absorption spectrometry (AAS) reveals high Al content in bone from the 3 demented and 2 of the non-demented patients. All had vitamin D-resistant osteomalacia. Using X-ray microanalysis Al was located in the bone of these five patients only. The Al had a highly focal distribution and was measured at up to 40 times higher concentration than by AAS but only in mineralisation nuclei of the calcification front or less than 2 micrometer into the mineralized bone. The study was done retrospectively on biopsies fixed in 10% buffered formalin, which almost certainly eluted some of the Al. In life, Al levels may have been higher than those we have detected.

Adolescent↗

A low dose regime of 1 alpha hydroxyvitamin D3 in the management of senile osteoporosis: a pilot study.

A comparison has been made between themetabolic consequences of daily administration for 6 weeks of 1.0 micrograms and 0.5 micrograms 1 alpha hydroxyvitamine D3 (1 alpha(OH)D3) in twenty patients with senile osteoporosis. There was no significant difference in the increase of calcium absorption which occurred in the two treatment groups between the beginning and end of the trial period. Serum and urinary calcium rose significantly in those receiving 1.0 micrograms 1 alpha(OH)D3 but not in the lower dosage group. Serum parathyroid hormone levels were suppressed in the higher dosage group only. There was a significantly greater rise of serum inorganic phosphate, and fall of serum magnesium, on the higher dosage, but no significant change in serum creatinine occurred in either group. It is, therefore, suggested that in long term therapy regimes for osteoporosis incorporating 1 alpha(OH)D3, 0.5 micrograms may be a more suitable daily dose than 1.0 micrograms 1 alpha(OH)D3.

Aged↗

The bone scan in clinical practice.

Radioisotopic bone scanning using technetium-99m labelled phosphate and diphosphonate compounds is a relatively new method of imaging the skeleton which has rapidly assumed major clinical importance. In this review of pathophysiology of bone uptake of radiopharmaceutical, the relative sensitivity of bone scan and radiograph, and the more important uses of bone scanning in clinical practice are described.

Bone Diseases↗

Semi-quantitative interpretation of the bone scan in metabolic bone disease: definition and validation of the metabolic index.

Certain easily recognisable features are commonly seen in the bone scans of patients with metabolic bone disorders. Seven such features have been numerically graded by three independent observers in the scans of 100 patients with metabolic bone disease and of 50 control subjects. The total score for each patient is defined as the metabolic index. The mean metabolic index for each group of patients with metabolic bone disease is significantly greater than that for the control group (P less than 0.001).

Bone Diseases↗