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Biomedical subjects

J E Compston

Publications and source records attributed to J E Compston.

At least 127 records · Page 7Linked to original sources
PubMed1992

Comparison of the effect of different reference data on Lunar DPX and Hologic QDR-1000 dual-energy X-ray absorptiometers.

We have investigated whether the Lunar DPX (software 3.4) and Hologic QDR-1000 dual-energy X-ray absorptiometers have comparable normal reference databases for the spine and femur of white UK and USA subjects. After conversion for systematic differences in absolute bone density values between the two systems, the reference databases were very similar for the spine in young subjects, but there were clear differences in the femur databases of young females and males of all ages. These differences were confirmed by comparing the percent age-matched and young values determined by the two systems for subjects scanned on both systems. Thus the diagnosis and management of a patient could differ, depending on the system used for the bone density measurements.

Absorptiometry, Photon↗
PubMed1992

Longitudinal study of cortical bone loss in patients with inflammatory bowel disease.

Bone mineral density of the radius was measured by single-photon absorptiometry in 50 patients with inflammatory bowel disease. Thirty-three had Crohn's disease and 17 ulcerative colitis; 25 were women. The mean age was 45 years (range, 18-70 years). Measurements were repeated in 39 of them after a mean follow-up period of 7.9 years (range, 7.1-8.2 years). In female patients the mean (95% confidence interval) annual change in radial bone mineral density was -0.74% (-1.34% to -0.14%) (P = 0.022), the greatest bone loss occurring in postmenopausal women (mean, -1.16% (-2.01% to -0.30%)). In male patients the mean annual rate of bone loss was -0.07% (-0.41% to 0.28%) (P = NS). Patients with abnormally low values at the first measurement remained osteopenic at the second measurement, whilst some others with normal values initially showed increased rates of bone loss and had a subnormal bone mineral density after the follow-up period. These results show increased rates of cortical bone loss in some patients with inflammatory bowel disease and emphasize the need to monitor bone mass in these patients so that prophylactic measures can be instituted.

Absorptiometry, Photon↗
PubMed1991

Age-related changes in resorption cavity characteristics in human trabecular bone.

The depth of resorption cavities in trabecular bone is an important determinant of bone structure and has implications relevant to the cellular pathophysiology of bone loss in osteoporosis. However, assessment of resorption depth has proved difficult and few data are available; in this study we report age-related changes in iliac crest trabecular bone obtained from 41 normal healthy subjects (21 female, 20 male) aged 22-80 years. Using 8-microns undecalcified sections stained with toluidine blue, resorption cavities were quantitatively assessed by a computerized technique in which the eroded bone surface is reconstructed and measurements made interactively. Maximum and mean cavity depth showed no significant correlation with age in either sex. The absolute length of eroded surface was unrelated to age but the eroded surface/BS (%) and the number of cavities/BS (/mm) showed a significant positive correlation with age (r = 0.384 and 0.386 respectively, p less than 0.05). No significant correlation was found between age and either cavity area or density. These results suggest that increased resorption depth does not contribute to age-related bone loss, although the possibility that deeper resorption cavities occur which result in trabecular penetration and are therefore unrecognizable cannot be discounted. The age-related increase in eroded surface/BS (%) reflects a decreased available trabecular surface and/or increased number of cavities rather than a greater surface length of individual cavities; alternatively it may indicate an increased resorption period. No evidence of increased resorption depth at the time of the menopause was found in this study.

Adult↗
PubMed1991

Total body calcium in patients with inflammatory bowel disease: a longitudinal study.

1. Serial measurements of total body calcium have been made by prompt gamma-neutron activation analysis in 13 patients with inflammatory bowel disease over a mean period of 23 months. Changes in spinal trabecular bone mineral density and radial shaft bone mineral content were also assessed by using quantitative computed tomography and single photon absorptiometry, respectively. 2. The mean annual decreases (95% confidence intervals) were: total body calcium, 7.8% (-12.0 to -3.7%; P less than 0.001); spinal trabecular bone mineral density, 2.5% (-5.0 to +0.1%; 0.05 less than P less than 0.1), radial bone mineral content, 2.1% (-3.4 to -0.8%; P less than 0.01). 3. No significant correlations were found between rates of change of the three variables. However, there were significant positive correlations between the baseline values for total body calcium and radial bone mineral content (r = 0.638, P less than 0.05), spinal bone mineral density and radial bone mineral content (r = 0.854, P less than 0.01), and total body calcium and spinal bone mineral density (r = 0.876, P less than 0.001). 4. These results demonstrate rapid decreases in total body calcium in patients with inflammatory bowel disease which, in conjunction with the significant decrease in radial shaft bone mineral content, indicate increased rates of cortical bone loss. Whilst values for bone mass at different skeletal sites showed positive correlations within individuals, no relationship was found between the rates of change in bone mass at these sites. 5. The rapid bone loss observed in some subjects emphasizes the importance of early detection of osteoporosis by bone densitometry and the need for effective prophylactic measures to be established in this group of patients.

Absorptiometry, Photon↗
PubMed1991

Low prevalence of osteomalacia in elderly patients with hip fracture.

In order to establish the prevalence of osteomalacia in elderly patients with hip fracture, trans-iliac biopsies were obtained from 49 patients, aged 67-92 years, admitted to Cardiff Royal Infirmary with hip fracture. Undecalcified sections were quantitatively assessed and the diagnosis of osteomalacia was made when there was an increase in mean osteoid seam width (greater than 15 microns) associated with a reduction in calcification fronts (less than 60% of osteoid-covered surfaces). Osteomalacia was present in only one patient; in the remaining patients, osteoid surface extent, volume and mean seam width were within normal limits. Thus osteomalacia, when defined by rigorous histomorphometric criteria, was rare in these elderly subjects with hip fracture.

Aged↗
PubMed1991

Comparative performance in vitro and in vivo of Lunar DPX and Hologic QDR-1000 dual energy X-ray absorptiometers.

The measured absolute bone mineral density values of spine and femur and their precision were compared on two dual energy X-ray absorptiometers, the Lunar DPX and the Hologic QDR-1000. There were systematic differences between the two systems, the Lunar DPX always giving a higher bone density value. The ratio of the mean Lunar DPX/Hologic QDR-1000 bone density measurements obtained in vivo was 1.13 g/cm2 for spine (L2-L4) and 1.20-1.43 g/cm2 for femur measurements. For both systems, short- and long-term precision (coefficient of variation) was below 0.5% for spine in vitro measurements and below 1.5% for neck of femur in vitro measurements. Precision of in vivo measurements was less good, especially for femur measurements. The coefficient of variation of spine measurements was dependent on bone density and deteriorated with decreased bone mineral density and increased body thickness.

Absorptiometry, Photon↗
PubMed1990

Determination of total body calcium by prompt gamma neutron activation analysis: absolute in vivo measurements.

Sequential TBCa measurements using the prompt gamma ray technique are firmly established and a number of patient groups are under investigation. A technique has been proposed for the absolute measurement of TBCa based upon the use of TBCl as an internal standard. Further work is needed to establish the validity of the method, but the initial results are encouraging.

Body Composition↗
PubMed1990

The relationship between spinal trabecular bone mineral content and iliac crest trabecular bone volume.

The relationship between spinal trabecular bone mineral density and iliac crest trabecular bone volume has been studied in 84 patients, 23 with primary osteoporosis, 19 with osteoporosis secondary to inflammatory bowel disease, and 42 with nonsteroid-treated rheumatoid arthritis. Spinal trabecular bone mineral density was measured in the first three lumbar vertebrae by quantitative computed tomography, and iliac crest trabecular bone volume was assessed histomorphometrically in sections from trans-iliac biopsies using computerized techniques. In all 84 patients, there was a significant positive correlation between the two measurements (r = 0.60, P less than 0.001). However, when the three patient groups were analyzed separately, a significant correlation was found in the group with secondary osteoporosis (r = 0.65, P less than 0.01) but not in the patients with primary osteoporosis (r = 0.07) or rheumatoid arthritis (r = 0.19). These results indicate that the relationship between spinal trabecular bone mineral density and iliac crest trabecular bone volume differs according to the underlying disease process, these differences possibly reflecting variations in skeletal patterns of bone loss in different types of osteoporosis.

Adolescent↗
PubMed1990

A computerised technique for the quantitative assessment of resorption cavities in trabecular bone.

A computerised technique is described for the quantitative assessment of resorption cavities in iliac trabecular bone. Using an Ibas II image analyser, the original bone surface, eroded by bone resorbing cells, is reconstructed using a curve fitting technique that maintains a smooth continuity with the trabecular bone on either side of the cavity. Resorption depths are measured using an interactive elastic circle; all identified cavities are measured regardless of whether or not resorption is complete, and the measurements made include mean and maximum cavity depth, cavity length, area, and adjacent trabecular widths. Results in 13 normal subjects are presented. The technique is reproducible, simple to operate, relatively rapid, and can be applied to less sophisticated image analysis systems.

Adult↗
PubMed1990

Osteoporosis.

Explore the source record for details and available documents.

Aged↗
PubMed1989

The relationship between resorption depth and mean interstitial bone thickness: age-related changes in man.

The amounts of bone resorbed and formed in each bone remodelling unit are important determinants of bone mass. The mean wall thickness (MWT), which indicates the amount formed, decreases with age; less is known about changes in resorption depth although two studies have reported some evidence in favor of an age-related decrease. We have calculated mean intersitial bone thickness (MIBT), which is indirectly related to resorption depth, from measurements of MWT and mean trabecular plate thickness (MTPT) in 48 normal subjects, aged 19-80 years. No significant age-related changes in MIBT were found in either sex, or in both sexes grouped together, whereas MWT and MTPT showed a significant decrease with age (P less than 0.001 and less than 0.05 respectively). Detailed analysis of possible relationships between MIBT and resorption depth revealed that, assuming formation never exceeds resorption, a decreased MIBT may be associated with an increased, constant, or decreased resorption depth; an increased MIBT can only result from a decreased resorption depth. A constant MIBT may indicate either an unchanged or decreased resorption depth; in the former case, MTPT is unchanged whereas a decreased resorption depth is associated with a decreased MTPT. In view of the age-related reduction in MTPT, our results are therefore consistent with earlier reports of an age-related decrease in resorption depth. No evidence for an increased resorption depth during the menopause was found in this study.

Adult↗
PubMed1989

Age-related changes in trabecular width and spacing in human iliac crest biopsies.

Age-related changes in trabecular width and spacing have been examined in iliac crest bone obtained from 96 normal subjects. The mean trabecular plate density and separation were calculated from values of trabecular bone volume and mean trabecular plate thickness. There was an age-related decrease in mean trabecular plate thickness with age in both sexes; this was statistically significant in males (P less than 0.02) but not in females. In females, there was a significant decrease in mean trabecular plate density (P less than 0.001) and increase in mean trabecular plate separation (P less than 0.001); similar but non-significant trends were observed in the males. These results demonstrate that trabecular thinning contributes to age-related bone loss in both sexes. Loss of trabeculae also occurs in both sexes, but to a greater extent in females than in males.

Adult↗
PubMed1989

Structural mechanisms of trabecular bone loss in man.

The relationship between trabecular thinning and loss of connectedness of the trabecular bone pattern has been studied in iliac crest bone samples from 89 normal subjects in order to determine the structural mechanisms underlying age-related bone loss. Trabecular width and structure were quantitatively assessed using computerized techniques. Highly significant negative correlations were found between the mean trabecular plate thickness and number of free ends/mm2 both in males (r = -0.571) and in females (r = -0.667) (P less than 0.001). Mean trabecular plate thickness also showed significant negative correlations with other structural indices indicating reduced connectedness, whereas positive correlations were found with those indices representing preservation of connectedness. Examination of the relative frequency of trabecular widths less than 100 microns revealed that only 2-5% of the trabecular surface would be susceptible to erosion by a resorption cavity of normal depth. These results indicate that trabecular thinning and erosion are interdependent processes in age-related bone loss. Since only a small percentage of the trabecular surface is susceptible to erosion, and resorption cavities normally occupy only 1-5% of the total trabecular surface, these findings imply that the site of activation of new BMUs may not be randomly distributed but may instead be preferentially located at sites of lower trabecular width.

Adult↗
PubMed1989

Elevated serum intact parathyroid hormone levels in elderly patients with hip fracture.

It has been postulated that secondary hyperparathyroidism contributes to bone loss and the high incidence of hip fractures in the elderly population, but there are no data on serum intact parathyroid hormone concentrations in these patients. In this study, serum intact parathyroid hormone (PTH) levels have been measured in 39 elderly patients with hip fracture; in addition, serum 25-hydroxyvitamin D3 and 1,25-dihydroxyvitamin D3 concentrations have been measured. Twenty patients (51.3%) had elevated serum intact PTH concentrations whilst five (12.8%) had abnormally low serum 25-hydroxyvitamin D3 levels and serum 1,25-dihydroxyvitamin D3 was reduced in only two. These results provide the first direct evidence for secondary hyperparathyroidism in elderly patients with hip fracture. Vitamin D deficiency is unlikely to be the sole cause of secondary hyperparathyroidism in these subjects and calcium deficiency by itself may also contribute.

Aged↗
PubMed1989

Reduced bone formation in non-steroid treated patients with rheumatoid arthritis.

The cellular basis of trabecular bone loss in rheumatoid arthritis was investigated in 45 non-steroid treated patients. Mean wall thickness, an indicator of the amount of bone formed per remodelling unit, mean interstitial bone thickness, which is related to resorption depth, and the extent of trabecular surface covered by osteoid, which reflects the number of remodelling units, were assessed in iliac crest biopsy specimens. The mean wall thickness was significantly reduced in the patient group when compared with controls matched for age and sex (mean (SD) 39.8 (5.4) v 51.6 (9.7) microns). There was no significant difference between patients and controls in the mean interstitial bone thickness (51.0 (26.4) v 61.4 (31.9) microns) or osteoid surface (16.7 (11.4) v 21.0 (10.5)%). These results show that reduced bone formation at the remodelling unit level is the predominant mechanism of bone loss in rheumatoid arthritis.

Adult↗