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Biomedical subjects

L D Hordon

Publications and source records attributed to L D Hordon.

9 recordsLinked to original sources
PubMed1992

Urinary excretion of pyridinium crosslinks of collagen in patients with osteoporosis and the effects of bone fracture.

Values for the urinary excretion of pyridinium crosslinks of collagen, pyridinoline and deoxypyridinoline, in a group of 30 elderly women with femoral fractures associated with osteoporosis and a group of 20 women without recent fracture but with overt or suspected osteoporosis were compared with 27 control subjects matched for age. Relative to the control group, the excretion of the crosslinks was significantly higher in the group with fractures and the group with osteoporosis. Fractures contributed markedly to the excretion of pyridinium crosslinks as the patients with fractures showed significantly higher excretion of pyridinoline and deoxypyridinoline than the group without recent fractures. This was confirmed by the fact that excretion of pyridinium crosslinks in patients with accidental bone fractures was significantly higher than for healthy control subjects matched for age and sex. The crosslinks appear to provide valid indices of bone resorption, but the effects of bone fracture must be considered in the clinical application of this technique.

Aged↗
PubMed1992

Endocrine disorders.

The effect of thyroxine replacement therapy on bone mass continues to attract attention. Although the advice of the American Thyroid Association to normalize serum thyroxine and thyroid-stimulating hormone concentrations is recommended, even physiologic doses of thyroxine may have an adverse effect on bone mass. The diagnosis and treatment of osteomyelitis in the diabetic foot is aided by magnetic resonance imaging, and long-term review of cases of diabetic femoral neuropathy emphasizes the good prognosis. Adrenal insufficiency as a complication of antiphospholipid syndrome is reviewed, and a useful physical sign, the acromegalic rosary, rediscovered. The association of sex steroids, oral contraception, and parity with rheumatoid arthritis is discussed. The outcome of pregnancy in women with juvenile rheumatoid arthritis is good, and quiescent disease does not appear to be permanently reactivated. Calcium deficiency, rather than vitamin D deficiency, is a cause of rickets in some Nigerian children.

Adrenal Gland Diseases↗
PubMed1991

Renal tubular dysfunction in rheumatic diseases.

Evidence of renal tubular dysfunction as defined by abnormal urinary levels of alpha 1 and beta 2 microglobulin with or without microalbuminuria was found in 47 (16.5%) of 285 patients with a variety of rheumatic diseases, compared with a prevalence of less than 1% in 500 healthy adults. Previous work from this unit has shown a prevalence of tubular dysfunction of 24% in patients with severe rheumatic disease admitted to hospital, probably associated with severe rheumatoid arthritis. Although our study confirms a high prevalence of renal tubular dysfunction, we have shown that it is related to age and intercurrent illness, particularly urinary tract infection, rather than to rheumatic disease or drug therapy, although it is possible drug therapy could add to a compound insult on ageing or damaged kidney.

Aged↗
PubMed1991

Endocrine disorders.

Recent studies emphasize the adverse effects of endocrine disorders on bone mass. Successful surgery for hyperparathyroidism results in an increase in bone mass, although impact on future fracture rates in these patients is unknown. The etiology of reduced bone mass in diabetes is still unclear, and the adverse effects of thyroxine replacement treatment on bone mass need to be carefully balanced against beneficial effects on hypercholesterolemia. Musculoskeletal problems in chronic renal failure are common, but investigations into their pathogenesis are complicated by the coexistence of renal endocrine failure and beta 2-microglobulin-related amyloid deposition in long-term dialysis patients. An improved definition of dialysis arthropathy is needed. The type of dialysis membrane does not appear to be important in the pathogenesis of this condition.

Bone Diseases↗
PubMed1990

The architecture of cancellous and cortical bone in femoral neck fracture.

The architecture of cancellous bone as well as quantity and quality is considered important in maintaining mechanical integrity. To determine whether abnormalities of architecture occur in femoral neck fracture we measured trabecular width and number in iliac crest bone biopsies of 68 women with femoral fracture and compared them with data from a postmortem series of age-matched women without known bone disease. Cortical thickness was measured in 27 of the fracture patients and 17 controls. After exclusion of ten biopsies with increased osteoid surface no significant difference was seen in mean trabecular width or number between fracture patients and subjects without fracture. Both thinning of trabeculae and loss of trabeculae contributed to low bone volume in femoral fracture patients. Direct measurements of trabecular number correlated with calculated mean trabecular plate density (P less than 0.001), and the percentage of trabeculae at any one of a range of trabecular widths in the fracture biopsies was similar to that in non-fracture subjects. No difference was seen in the architecture of cancellous bone with age, fracture trauma or between subcapital and intertrochanteric fracture in fracture subjects. Cortical thickness, however, was related to age in both fracture and control subjects (P less than 0.05). There was no difference in cortical thickness between age-matched fracture and control subjects. Patients with intertrochanteric fracture had lower cortical thickness (P less than 0.02) and were older (P less than 0.01) than patients with subcapital fracture.

Aged↗
PubMed1990

Osteomalacia and osteoporosis in femoral neck fracture.

Iliac crest bone histomorphometry, plasma and urine biochemistry and clinical history were examined in 78 unselected patients (68 women, 10 men) at the time of femoral fracture. Histological abnormalities occurred in 56 of the 78 biopsies. The commonest of these was a low bone volume of less than 15% which, irrespective of other abnormal histological features, was present in 37 of the biopsies. On the basis of the histomorphometry, patients could be classified into four main groups. Normal histomorphometry (bone volume greater than 15%, osteoid surfaces less than 24%, mineralising surface greater than 60%) was present in 22 patients, 23 had osteoporosis as the only abnormality (bone volume less than 15%, osteoid surface less than 24%, mineralising surface greater than 60%), nine had osteomalacia (osteoid surfaces greater than 24%, mineralising surface less than 60%, osteoid width greater than 13 microns) and 13 had decreased mineralising surfaces. Of the remainder, five had increased osteoid surface and six had insufficient osteoid to assess mineralising surface. Plasma and urine biochemistry in the four groups showed that, compared to age-matched controls, all groups had reduced plasma albumin. In comparison to the group with normal histomorphometry, patients with osteoporosis had a higher plasma calcium (P less than 0.01), tubular reabsorption of calcium (P less than 0.05) and plasma vitamin D binding protein (P less than 0.01); patients with osteomalacia had a higher plasma creatinine (P less than 0.02) and parathyroid hormone (P less than 0.02) and lower plasma 24,25-dihydroxyvitamin D (P less than 0.02), urinary calcium/creatinine ratio (P less than 0.02) and tubular reabsorption of phosphate (P less than 0.02). The biochemistry in patients with decreased mineralising surface was no different from patients with a normal biopsy. The prevalence of both osteoporosis and osteomalacia increased with age and, in subjects over the age of 90, osteoporosis occurred in 71% of patients and osteomalacia occurred in 29% of patients. The osteomalacic group were significantly older than the other three groups (P less than 0.05). The histomorphometry did not relate to the site of fracture (subcapital or intertrochanteric). A history of stroke, gastrectomy, rheumatoid arthritis, steroid treatment, thyroid disease, alcohol abuse and anti-convulsant therapy was present in patients with femoral fracture but did not relate to any particular histomorphometric classification.

Age Factors↗
PubMed1987

Vitamin D metabolism in women with femoral neck fracture.

Abnormalities in plasma vitamin D metabolites and an increased prevalence of osteomalacia have been described in elderly patients sustaining a fracture of the femoral neck. In order to investigate whether the plasma concentrations of the vitamin D metabolites are normal, and whether vitamin D deficient osteomalacia in patients with femoral fracture can be diagnosed using biochemical criteria alone, we have studied before and after 7 days of 40 micrograms oral 25-hydroxyvitamin D3 elderly patients admitted to hospital with a femoral fracture, elderly patients undergoing elective replacement of the femoral head and elderly control patients in hospital with no clinical evidence of bone disease. Plasma 25-hydroxyvitamin D (25(OH)D) and 24,25-dihydroxyvitamin D increased after 7 days of oral 25-hydroxyvitamin D3 to the same levels in the three groups, but in contrast to the controls there was no significant increase in plasma 1,25-dihydroxyvitamin D or radiocalcium absorption in femoral fracture and hip replacement patients. However, when femoral fracture patients were restudied 6-12 months after fracture, plasma 1,25-dihydroxyvitamin D increased after oral 25-hydroxyvitamin D3 to the same extent as it had in the control patients. We conclude that reduced calcium absorption due to low plasma 25(OH)D levels, i.e., vitamin D insufficiency is common in all elderly patients. Furthermore biochemical criteria for diagnosis of vitamin D-deficient osteomalacia are of very limited use at the time of fracture in elderly patients since there is a failure of production of 1,25 dihydroxyvitamin D which resolves within 6-12 months of the fracture. This failure makes the 1,25-dihydroxyvitamin D response to oral 25(OH)D an unreliable guide to the presence of vitamin D-deficient osteomalacia at the time of fracture. The abnormality in 1,25-dihydroxyvitamin D is also present in patients undergoing hip replacement surgery, and is therefore unlikely to be involved in the aetiology of femoral neck fracture. It may, however, contribute to the morbidity after fracture.

24,25-Dihydroxyvitamin D 3↗