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Biomedical subjects

D M Reid

Publications and source records attributed to D M Reid.

At least 145 records · Page 8Linked to original sources
PubMed1994

Population screening for low bone mineral density: do non-attenders have a lower risk of osteoporosis?

Poor compliance may be detrimental to the effectiveness of a screening programme if those at greatest risk of the disease do not attend. Therefore we undertook a study to test whether non-attenders to a screening programme for low bone density, a risk factor for osteoporosis, were at a differential risk of low bone density compared with attenders. Seven hundred and eighty-nine women aged 45-49 years living within 32 km of Aberdeen were selected at random from the Community Health Index and invited to attend for screening for low bone density as a risk of factor for osteoporosis. Attenders and non-attenders were surveyed regarding their risk factors for osteoporosis. Non-attenders were significantly heavier than attenders. In addition, 6 non-attenders who subsequently chose to attend had significantly higher body weight and bone mineral density, at Ward's triangle, than initial attenders. Non-attenders to a screening service for bone density may be at lower risk of developing osteoporosis. Non-attendance, therefore, would not be detrimental to the cost-effectiveness of a screening service for bone density. However, this study indicates there is a potential for response bias in studies of bone density and osteoporosis.

Bias↗
PubMed1994

Effects of sulphur dioxide (SO2) on growth and flowering of SO2-tolerant and non-tolerant genotypes of Phleum pratense.

The objective of this study was to compare the growth and interaction of clipping and sulphur dioxide (SO(2)) exposure on SO(2)-tolerant and non-tolerant genotypes of Phleum pratense at two field sites along an SO(2)-concentration gradient. Sulphur-dioxide-tolerant and non-tolerant genotypes of Phleum pratense were identified from indigenous populations that had been collected along the same SO(2)-concentration gradient in southern Alberta, Canada. Physiological differences between the two genotypes were confirmed by supplying leaves with (14)CO(2) and examining the assimilate partitioning between the genotypes. For the field experiment, clones of each genotype and seedlings grown from commercial seed were planted at two different field sites along an SO(2)-emission gradient. There were no differences in growth between the genotypes at the two field sites after the first year except that the SO(2)-tolerant clones had a greater percentage of root length colonised by vesicular-arbuscular (VA) mycorrhizal fungi. After the second growing season, there was a significant decrease in the number of inflorescences produced by plants exposed to SO(2), particularly by the non-tolerant genotype. The added stress of defoliation appeared to increase the sensitivity of flowering to SO(2), again particularly in the non-tolerant genotype. The results of the field study showed that flowering as opposed to vegetative plant growth was more sensitive to long-term low-concentration SO(2) exposure and that this sensitivity was compounded by the stress interaction of defoliation.

Journal Article↗
PubMed1994

Factors associated with onset of menopause in women aged 45-49.

This paper uses a cross-sectional sample of women aged 45-49 to investigate factors that might be associated with an early menopause. Using logistic regression analysis we found that age, smoking, age of maternal menopause, parity, social class, meat and alcohol consumption were all independently associated with an early natural menopause. Meat, alcohol consumption and maternal menopausal age do not seem to have been previously noted as associated with the timing of the menopause. These associations would merit further study, preferably using prospective data. However, this study in line with much previous work shows that smoking is associated with a reduction in menopausal age.

Age Factors↗
PubMed1994

Can radiologists detect osteopenia on plain radiographs?

The main purpose of this study was to compare subjective estimates of vertebral ostepenia with bone mineral density (BMD) measurements of the same region in 200 (107 male, 93 female) subjects, aged 52-90 years, invited randomly from the community. Standardized plain thoracolumbar radiographs were examined by three senior radiologists, and given a semiquantitative osteopenia score using the method of Saville. The BMD of the anteroposterior (AP) lumbar spine and femoral neck was measured by dual energy X-ray absorptiometry. In addition BMD measurements were compared in subjects without significant vertebral deformity, and those with mild (20-25%) or definite (> 25%) reductions of vertebral height. For the Saville score, intraobserver agreement was moderate to good (kappa 0.46-0.57), and interobserver agreement was fair to moderate (kappa 0.25-0.41). Although the overlap between gradings was considerable, BMD was significantly related to visually estimated osteopenia. Subjects without apparent radiographic osteopenia (Saville grade 0) had a low risk (9-15%), compared to those with definite osteopenia (64-86%), of falling below the lowest quartile of BMD at either the femoral neck or the AP spine. In women (but not men), BMD measured at the hip and spine was related to vertebral deformity.

Absorptiometry, Photon↗
PubMed1994

Relationship of urinary pyridinium crosslinks to disease extent and activity in osteoarthritis.

Urinary crosslinks, pyridinoline and deoxypyridinoline, have been shown to be elevated in RA and OA. This study confirmed this elevation, with levels in patients with predominantly knee OA higher than those with nodal OA and hip OA. Intra-articular corticosteroid injection was followed by a significant fall in urinary crosslinks, which was associated with a corresponding improvement in articular index and pain score, although there was no overall correlation between crosslink levels and the clinical indices studied. Collagen crosslinks may be of value as markers of disease activity in OA.

Adrenal Cortex Hormones↗
PubMed1994

Age and sex influences on fall characteristics.

OBJECTIVE: To investigate age and sex influences on fall characteristics. METHODS: A total of 1243 subjects (517 males and 726 females) aged 50 years and over and drawn from population based sampling frames were invited to complete an interviewer administered questionnaire concerning descriptive characteristics of falls experienced in the previous four months. Information collected included details about the part of the body to strike the ground, direction of the fall, level of trauma and whether or not injury or fracture was sustained. RESULTS: One hundred and seventy two subjects reported a fall in the previous four months. Restricting analysis to the 142 subjects who fell from a standing height or less, females aged 50-64 years were more than twice as likely to fall onto their hand compared with older females (odds ratio (OR) = 2.2; 95% confidence interval (CI) 0.8 to 6.2) and at all ages (50+) were more than three times as likely to fall on their hip compared with males (OR = 3.4; 95% CI 1.0 to 11.5). Compared with older males, males aged 50-64 were more likely to fall sideways (OR = 5.1; 95% CI 1.5 to 17.4) and less likely to fall forwards (OR = 0.4; 95% CI 0.1 to 1.1). CONCLUSION: There is a potentially clinically important variation in fall type by age and sex. In particular, this variation might explain patterns of occurrence of hip and Colles' fracture.

Accidental Falls↗
PubMed1994

Precision and accuracy of measurements of whole-body bone mineral: comparisons between Hologic, Lunar and Norland dual-energy X-ray absorptiometers.

Measurements of whole-body bone mineral made by Hologic, Lunar and Norland dual-energy X-ray absorptiometers have been compared. It was found that in each case the results were changed by new software protocols introduced by the manufacturers during the course of the study. With a moderately anthropomorphic model, the later software corrected some anomalies of regional bone mineral content (BMC) observed earlier. There was some slight dependence of total BMC on thickness and fat proportion and up to 15% difference between instruments. Measurements on volunteers showed good precision, but there were differences between instruments made by different manufacturers. There were high correlations, but the slopes of regression lines suggested differences of calibration of up to 8%; the standard errors of the estimates were 110 to 190 g. with maximum deviations from regression of 17%. There were regional disparities in BMC, particularly in the trunk, which arise (in part at least) from the imposition of a higher bone threshold by Hologic. From the pattern of results it was concluded that different assumptions were made by the manufacturers, particularly concerning the fat distribution model, which preclude the interchangeability of results from different instruments.

Absorptiometry, Photon↗
PubMed1994

Comparisons between Hologic, Lunar and Norland dual-energy X-ray absorptiometers and other techniques used for whole-body soft tissue measurements.

OBJECTIVES: Assessment of the precision and accuracy of dual-energy X-ray absorptiometers (DXA) from three manufacturers, used for measuring soft-tissue composition, and comparability with each other and other techniques. DESIGN: Measurements of an anthropomorphic model of variable composition and thickness. 11 volunteers measured with each instrument and by underwater weighing (UWW) and three brands of bioelectric impedance analysis (BIA) apparatus. RESULTS: New software, introduced by each manufacturer during the course of the investigation, led to changes in measured fat proportion. The precision of determination of fat proportion by DXA in the (small) model was 3-4% (coefficient of variation), with little difference between brands. In vivo precision was 2-3%. In the model, measurements of % fat differed from the nominal values, but variation with thickness was small. There were significant mean differences of total fat proportion in the volunteers between pairs of DXA instruments of 2.6-6.3% fat. The SDs of the differences were 1.8-2.9% fat. Regional differences were greater, with trunk % fat being particularly underestimated by Hologic relative to Lunar and Norland. Compared with UWW, mean % fat was the same for Hologic, but higher for Lunar and Norland. SDs of 4% demonstrated inadequate agreement. The differences varied with proportion of bone in lean tissue, questioning the assumption of constant density of lean tissue in UWW. There were no mean differences of % fat between the BIA instruments and DXA and UWW, but SDs of 3-6% suggest that BIA using these instruments does not offer an acceptable accuracy in estimating fat proportion. CONCLUSIONS: UWW has limitations as a reference method. DXA is a useful technique, but its limitations, particularly regarding assumptions about fat distribution, must be borne in mind. The differences of fat proportion recorded by the three DXA instruments are such as to preclude interchangeability in measurements of individual subjects or in clinical trials.

Absorptiometry, Photon↗
PubMed1994

Bone loss associated with a high fibre weight reduction diet in postmenopausal women.

OBJECTIVE: To examine the effect of high fibre weight reduction on bone density in postmenopausal women. DESIGN: Case-control study. SETTING: Hospital outpatient dietetic clinic and Osteoporosis Screening Unit. SUBJECTS AND INTERVENTIONS: Sixteen overweight volunteers who followed a high fibre reducing diet for 6 months, to lose 20% of excess body weight (above body mass index 25 kg/m2), and returned to their starting weight by the end of a further 6 months. Forty-six non-dieting controls, matched for age and years postmenopause, selected from screening unit volunteer register. RESULTS: Annual percentage changes in lumbar spine bone mineral density, measured by dual energy X-ray absorptiometry were: controls -2.5% (SE 0.5), dieters -4.8% (0.9), 95% confidence interval of difference between groups -0.2 to -4.3% (P = 0.03); femoral neck bone density controls -2.5% (0.5), dieters -2.1% (0.9), 95% confidence interval of difference -1.7 to 2.5% (P = 0.69). CONCLUSIONS: High fibre weight reduction in postmenopausal women significantly increased annual bone loss from the lumbar spine. This loss was not reversed by weight regain in the second 6 months. Repeated cycles of high fibre weight loss and weight gain may increase the risk of spinal osteoporosis.

Absorptiometry, Photon↗
PubMed1993

Immunoglobulins from normal sera bind platelet vinculin and talin and their proteolytic fragments.

Our previous finding that normal serum immunoglobulins bind to internal platelet proteins on Western blots led us to further identify these proteins and determine the possible significance of autoantibodies against them. A 95-Kd protein reactive with immunoglobulins in most normal sera and easily confused with gpIIIa was shown to be a fragment of vinculin generated by calpain proteolysis. Identity was established by peptide sequencing of the protein purified from platelets stored without specific protease inhibitors. Normal immunoglobulins bound intact vinculin (117 Kd) and metavinculin (152 Kd), and their 105-, 95-, and 80- to 85-Kd proteolytic fragments. IgG in 89%, and IgA and IgM in 100% of normal sera reacted in titers of 10 to 1,000 with purified vinculin. In addition, IgG in 79%, and IgA and IgM in 93% of normal sera reacted in titers of 10 to 5,000 with talin (235 Kd), another cytoskeletal protein, and its 200-Kd proteolytic fragment. IgGs in sera from animals of several different phylogenetic classes also reacted with human vinculin and talin on Western blots. Frequency of occurrence, titers, and classes of antivinculin and antitalin autoantibodies in patients with thrombocytopenia did not differ discernibly from those of normal individuals. These antibodies had no effect on platelet aggregation or clot retraction, and no apparent pathogenic significance, but their widespread presence and the variability in extent of proteolysis of platelet preparations used for Western blots can complicate interpretation of patterns obtained with sera from patients with presumed immune-mediated thrombocytopenias.

Antibodies, Monoclonal↗
PubMed1993

Bone mineral density of the hip and of the anteroposterior and lateral dimensions of the spine in men with rheumatoid arthritis. Effects of low-dose corticosteroids.

OBJECTIVE: To assess bone mineral density (BMD) in men with steroid-treated rheumatoid arthritis (RA). METHODS: Dual-energy x-ray absorptiometry (DXA) was used to measure BMD in 40 men with RA, 20 of whom were receiving low-dose corticosteroids (< or = 10 mg prednisolone daily), and in 20 healthy, age-matched male controls. RESULTS: BMD was significantly reduced at the femoral neck and greater trochanter in both groups of RA patients, and at the spine from the anteroposterior dimension in the steroid-treated group. CONCLUSION: Low-dose steroid therapy may induce excess axial osteopenia in men with RA.

Adrenal Cortex Hormones↗
PubMed1993

Recruitment methods for screening programmes: the price of high compliance.

High population compliance is seen as a prerequisite for an equitable screening service. To achieve high compliance fixed appointments are usually advocated. However, the costs of achieving high compliance have not previously been described. To assess the costs of achieving high compliance we have used a randomised trial of two common appointment methods: 800 women aged 45-49 living within 20 miles of Aberdeen were selected at random from the Community Health Index. They were randomly assigned to receive one of two letters--one offering a fixed appointment, the other inviting them to telephone to make an appointment. For a defined population fixed appointments achieved high compliance but only by reducing the opportunities for screening; for every 100 women screened, 110 additional women were denied the opportunity of a screening test. In contrast the open letters of invitation achieved efficiency by increasing the number of women screened with given resources within a larger population. Thus for screening services with fixed budgets, high compliance is achieved only by screening fewer people.

Appointments and Schedules↗
PubMed1993

Screening for osteoporosis: comparison between dual energy X-ray absorptiometry and broadband ultrasound attenuation in 1000 perimenopausal women.

This paper compares dual-energy X-ray absorptiometry (DXA) of the spine and hip and broadband ultrasound attenuation (BUA) of the os calcis in 1000 perimenopausal women aged between 45 and 49 years who attended a randomized Osteoporosis Screening Programme. Significant correlations were found between all DXA results and BUA, with the trochanter giving the best numerical correlation with BUA (r = 0.354, p < 0.0001). BUA was not successful in predicting women with low DXA measurements, with only 44.0% of the women whose spinal DXA falls within the lowest quartile being in the lowest quartile of BUA. Although BUA is a poor predictor of spinal and hip bone mineral density it may provide additional structural information important in fracture prediction.

Absorptiometry, Photon↗
PubMed1993

Mitosis and apoptosis of microglia in vivo induced by an anti-CR3 antibody which crosses the blood-brain barrier.

Microglia, the resident tissue macrophages of the central nervous system, have a highly differentiated morphology and do not express many of the antigens typically associated with other tissue macrophages. Activation of microglia is associated with a change in morphology and an increase in their repertoire of antigen expression. Microglia become activated in many neuropathological conditions including chronic neurodegenerative diseases and human immunodeficiency virus neuropathology, yet little is known of the mechanisms involved. Here we demonstrate for the first time that microglia can be activated and induced to divide and/or undergo apoptosis via a beta 2-integrin (complement receptor type 3, CR3, Mac-1 or CD11b/CD18) using an anti-CR3 monoclonal antibody (McAb5C6). This antibody, which has been shown to block myelomonocytic recruitment during central nervous system inflammation, is unique in that it can cross the intact blood-brain barrier to activate microglia. Since CR3 not only binds the iC3b component of the alternative complement cascade but also denatured proteins this suggests a potential route for microglia activation in neuropathological conditions.

Animals↗