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Biomedical subjects

M Revilla

Publications and source records attributed to M Revilla.

At least 73 records · Page 4Linked to original sources
PubMed1994

Influence of weight and seasonal changes on radiogrammetry and bone densitometry.

We studied the behavior of radiogrammetric and densitometric measurements in relation to season and body weight in a group of 30 healthy premenopausal women. Measurements were made at 6-month intervals, in summer/fall when bone density increases and in winter/spring when bone density declines. Total body bone mineral content (TBBMC) and regional bone mineral content (RBMC) were measured using dual-energy X-ray absorptiometry (DXA). Metacarpal radiogrammetry was carried out with computed radiography. Weight and body mass index increased significantly in winter (P < 0.05) and total body and RBMC decreased (P < 0.001). The opposite occurred in summer: weight and body mass index decreased significantly (P < 0.05) and total body and regional bone mineral content increased (P < 0.001). Differences in TBBMC persisted when the measurement was corrected for weight (TBBMC/W) (P < 0.001), but not for metacarpal cortical thickness corrected for weight. In the first measurement made there were significant relations between weight and both TBBMC (P < 0.001) and metacarpal cortical thickness (P < 0.005). The relation between weight and TBBMC remained significant in later measurements, but the relation between weight and metacarpal cortical thickness ceased to be significant in the second and fourth measurements. Our results show that there is an important seasonal variation in bone mass and that DXA is more sensitive than radiogrammetry in registering these changes.

Absorptiometry, Photon↗
PubMed1994

beta 2-Microglobulin in Paget's bone disease.

On the basis of earlier findings of increased serum beta 2-microglobulin concentration in women with postmenopausal osteoporosis, we decided to study serum beta 2-microglobulin concentration in other bone diseases. In 28 patients with untreated Paget's bone disease, serum beta 2-microglobulin concentration was normal (1.49 +/- 0.41 mg/liter versus 1.36 +/- 0.21 mg/liter in 42 control subjects, P = ns), a finding that contradicts reports in the literature. We found that serum beta 2-microglobulin concentration was related negatively and significantly (r2 = -0.154, P = 0.0354) with serum total alkaline phosphatase concentration, but not with serum tartrate-resistant acid phosphatase concentration (p = ns). Urinary elimination of beta 2-microglobulin was lower in the patients with Paget's disease than in the controls (34 +/- 28 versus 120 +/- 21 mg/liter, P < 0.001). These findings suggest that beta 2-microglobulin behaves similarly to osteocalcin (BGP) in Paget's bone disease and that its concentration remains within normal levels perhaps because of the rate of reuptake of beta 2-microglobulin in bone neoformation.

Acid Phosphatase↗
PubMed1994

Cortical versus trabecular bone mass: influence of activity on both bone components.

Motivated by the controversy in the literature concerning the influence of activity on bone mass and on its cortical and trabecular components, a study was made using computed peripheral tomography (Stratec XCT 900) of the total, cortical, and trabecular bone mass of the dominant and nondominant upper extremities of 50 apparently normal subjects (average age 26 +/- 6 years). No differences were observed in the trabecular bone compartment, but the cortical compartment was greater (P < 0.001) in the dominant extremity. There was also a significantly greater total bone mass in the dominant extremity which we attributed to greater cortical mass (P < 0.025) given the highly significant correlation (r2 = 0.904, P = 0.0001) between total and cortical bone mass and the less significant correlation between total and trabecular bone mass (r2 = 0.479, P = 0.0001).

Adult↗
PubMed1994

Longitudinal study of the effect of calcium pidolate on bone mass in eugonadal women.

Seventy-two eugonadal women, mean age 39 +/- 4 years, with a z score for total body bone mineral content (BMC) of less than -1.5 (mean -1.80 +/- 0.12) were selected from a previous screening study of normal values of total body and regional BMC in women using dual-energy X-ray absorptiometry. The women were distributed into two groups: 36 women undergoing treatment with 1 g/day of elemental calcium in the form of calcium pidolate and 36 women not treated. One year later, total body BMC, regional BMC in arms, legs and trunk, 24-hour urinary calcium excretion (Ca 24 hour), fasting urinary calcium/creatinine ratio, and serum tartrate-resistant acid phosphatase concentration were measured in both groups. There was a significant increase in total body and regional BMC (P < 0.001) in the group taking calcium pidolate. The increase was greater in arms and legs (2.5%) than in trunk (1.7%), being 2.6% for total body BMC. The z score increased from -1.81 +/- 0.13 to -1.52 +/- 0.12 (16%, P < 0.001). The corporal index did not change, and total body BMC corrected for fat-free body mass increased by 6.7% (P < 0.001). These changes were accompanied by an increase in 24-hour urinary calcium excretion and a decrease in urinary calcium/creatinine ratio and serum tartrate-resistant acid phosphatase concentration (P < 0.05 for all). There was a correlation between cumulative calcium dose at the end of treatment and gain in total body BMC (r2 = 0.925, P < 0.001). The untreated group showed no changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1994

Comparison between metacarpal bone measurements by computarized radiogrammetry and total body DEXA in normal and osteoporotic women.

We evaluated the precision of metacarpal radiogrammetry by computed radiography as a technique for bone mass measurement. Measurements obtained using this method were compared with densitometric measurements of total body bone mass using dual-energy X-ray absorptiometry. Our results showed that the coefficients of variation for radiogrammetric measurements were similar in 60 women with osteoporosis and in 100 normal women: 0.7% in both groups for external diameter of the second metacarpal, 2.41% in the normal women and 2.03% in the women with osteoporosis for internal diameter, and 2.3% and 2.4%, respectively, for cortical thickness. Except for external metacarpal diameter, which did not differ between normal and osteoporotic women, all the measurements were smaller in the women with osteoporosis (p < 0.001). The correlation between metacarpal cortical thickness and total body bone mineral content was r2 = 0.462 in the women with osteoporosis, r2 = 0.476 in the controls, and r2 = 0.522 in the two groups combined (all p < 0.001). There was a significant correlation (p < 0.001) between cortical thickness and densitometric metacarpal measurements of both the diaphysis and epiphysis. These results confirm the value of radiogrammetry as a technique for quantitating bone mass under normal and pathological conditions. Additional advantages of the method are minimal radiation dose delivered, possibility for storing the image and data, and technical facility.

Absorptiometry, Photon↗
PubMed1994

The four-compartment models in body composition: data from a study with dual-energy X-ray absorptiometry and near-infrared interactance on 815 normal subjects.

With the aim of studying body composition according to a four-compartment model in different age groups of healthy subjects, total body water (TBW), body fat (BF), lean body mass (LBM), and total-body bone mineral content (TBBMC) were estimated with dual-energy x-ray absorptiometry (DEXA) and near-infrared interactance in 308 normal males and 507 normal females aged 15 to 83 years. Subjects were divided into 5-year groups up to the age of 50, and then into 10-year groups. In both sexes, BF showed a positive correlation with age (P < .001) and was higher in females aged 40 to 44 compared with younger groups. LBM decreased with age only among males (P < .05). A similar finding was observed with TBW. TBBMC values did not differ between sexes in the 15- to 19-year-old group, and were greater in males in the remaining age groups. This parameter did not vary among females until menopause, and decreased in the 50- to 59-year-old group (P < .001) and from the age of 60 onward (P < .001). Height decreased (P < .001) and weight increased with age (P < .001). Both in male and female groups height and weight correlated with TBBMC (P < .001). When corrected for weight, TBBMC did not vary except in men older than 50, who showed lower values (P < .005). When corrected for height, TBBMC only changed in women aged 30 to 34 and 35 to 39.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1994

Determinants of total-body and regional bone mineral content and density in postpubertal normal women.

Some investigators consider body fat the main determinant of bone mass in women, and others, weight. Although genetics may be the primary determinant of peak bone mass, modifiable secondary factors such as nutrition and hormone exposure may significantly affect bone mass accretion during the second decade of life. To determine the principal determinants of bone mass, we analyzed total and regional bone mass (by dual-energy x-ray absorptiometry), weight, height, percentage body fat, and lean body mass in a group of 50 young women ranging in age from 14 to 18 years. Total-body bone mineral content, total-body bone mineral density, and total-body bone mineral density corrected for height, analyzed by multiple correlation, were not related to percentage body fat, although percentage body fat did correlate with the regional bone mineral content of the trunk (P < .001), legs (P < .01), and pelvis (P < .001). Lean body mass correlated with total-body bone mineral content and density, total-body bone mineral density corrected for height (P < .001), and regional bone mineral content of the trunk (P < .05), arms (P < .01), and legs (P < .001), but not with regional bone mineral content of the pelvis and head. Weight correlated significantly (P < .001) with all bone mass measurements except regional bone mineral content of the head, where the significance was P less than .05. Similar results were obtained by multiple regression analysis. These results indicate that weight, not body fat, is the main determinant of bone mass in postpubertal women.

Absorptiometry, Photon↗
PubMed1994

Ultrasound bone velocity and metacarpal radiogrametry in hemodialyzed patients.

Bone density measurements based on the rate of propagation of ultrasound waves provide information on bone elasticity, which is largely dependent on cortical bone structure. Both bone density and cortical bone present variations dependent on age and sex. As far as we know, bone elasticity in patients on hemodialysis has not been studied, so we used ultrasound bone velocity and metacarpal radiogrametry to study 23 adult patients with end-stage renal disease. The patients' results were compared with those of a group of 23 healthy subjects matched by age and sex. The measurements obtained by both ultrasound bone velocity and metacarpal radiogrametry were lower in hemodialyzed patients (p < 0.025) than in controls and there was a good correlation between the two measurements (r2 = 0.561; p < 0.0007). Neither of the measurements correlated with age or time on dialysis. These results show that bone elasticity in dialyzed patients is diminished, which could be an important factor in the bone lesions of these patients.

Adult↗
PubMed1994

Total and regional bone mineral content in primary hyperparathyroidism: sex differences.

Changes in cortical and trabecular bone mass occurring in primary hyperparathyroidism are the subject of controversy. We measured the total and regional bone mass in a group of patients and controls and analyzed the observed changes with respect to sex and other characteristics. Parathormone, serum calcium, serum phosphorus, tubular resorption of phosphates, alkaline phosphatase, and tartrate-resistant acid phosphatase differed significantly (p < 0.001 for all) between patients and controls. All the patients had significantly less total and regional bone mass; the regional bone mass of the arms did not differ. When analyzed according to sex, we found that women had a significant reduction in bone mass in all the zones studied (p < 0.001), whereas men had a significant decrease in bone mass only in the head (p < 0.025). Our findings show that hyperparathyroidism is accompanied by a loss of bone mass except in the arms, and that predominantly both cortical bone (legs, pelvis and skull) and trabecular bone (trunk) are affected. This means that the skeleton suffers generalized bone loss and a significant reduction in total body calcium content. Although we did not study many men, their bone involvement was less intense, and there was a clear difference between the sexes in this respect.

Aged↗
PubMed1993

Biochemical markers of nutrition in osteoporosis.

Thirty-six women with vertebral osteoporosis showed significantly decreased levels of biochemical markers of nutrition, transferrin (P < 0.001), prealbumin (P < 0.001), retinol binding-protein (P < 0.001), and fibronectin (P < 0.001), compared with 40 healthy women of similar age. Multiple regression analysis showed a significant (R2 = 0.509; P = 0.0068) correlation between bone mineral content and biochemical markers of nutrition in the osteoporotic patients but not in the control group. These data suggest that postmenopausal osteoporosis may be associated with a nutritional deficiency.

Aged↗
PubMed1993

Bone changes in postmenopausal Spanish women.

Total body bone mass (TBBM), axial bone mass (trunk = chest and spine), and peripheral bone mass (arms and legs) were determined in 258 normal, slow bone mass loser, postmenopausal women, as determined by previous biochemical studies, in order to study the degree of bone mass reduction due to menopause. The subjects of this study were divided into 5-year groups on a year-since-menopause basis. The first group corresponded to 1-5 years since menopause, and the last group to 25 years or over since menopause. An important and significant reduction in trunk bone mass (-12.3%, P < 0.001) and TBBD (-5.8%, P < 0.002), without changes in head, arms, and legs was observed in the first 5-year group. In the next 5-year group, a significant reduction was observed in all body areas, but at a higher rate in the peripheral skeleton (-9% in arms and -7.3% in legs). A slow down in bone mass loss was observed in the period between 10 and 25 years since menopause. These values became significant again after 25 years since menopause at the axial (-28.9%, P < 0.001) and TBBD (-20.3%, P < 0.05) level. Aside from providing percentages of bone mass reduction with respect to age and time since menopause, these data also indicate that measurements of specific body areas may not be extrapolated to others due to different loss in different body areas, and that there is a marked bone loss rate in the axial skeleton in the first 5 years since menopause.

Absorptiometry, Photon↗
PubMed1993

Total and regional bone mineral content in women treated with GnRH agonists.

Changes in bone mineral content induced by GnRH agonists were investigated by measuring total body bone mineral content (TBBM) and regional bone mineral content (BMC) (arms, legs, trunk, pelvis) and densities with dual energy X-ray absorptiometry in 25 premenopausal women before and after a 6-month treatment with gonadotropin-releasing hormone (GnRH) agonists. Biological markers of bone remodeling, estrogens, luteinizing hormone, and follicle-stimulating hormone were also measured. Weight and body mass index increased significantly after treatment (P < 0.05), and TBBM, corrected for weight (TBBM/W), decreased (P < 0.001). The changes in BMC that we observed ranged from +2.5% to -6.9%. The greatest decrease in regional BMC occurred in the trunk (4.4%, P < 0.001), with TBBM decreasing by 2.1% (P < 0.001). No significant changes were observed in the limbs. Tartrate-resistant acid phosphatase (TRAP) increased significantly after treatment (P < 0.001) and a significant negative correlation between TRAP and TBBM (P < 0.001) and between TRAP and estradiol (P < 0.001) were observed before treatment. The lack of changes observed in the BMC of the limbs indicate that GnRH agonists cause a preferential loss of BMC in trunk osseous structures, a situation similar to that of the first years of menopause.

Absorptiometry, Photon↗
PubMed1993

Beta 2-microglobulin in postmenopausal osteoporosis.

The so-called bone-derived growth factor, or beta 2-microglobulin, has a regulatory function in bone metabolism, stimulating osteoclastic activity. Osteoclastic activity is enhanced in postmenopausal osteoporosis, suggesting that beta 2-microglobulin concentration may also be increased in this disease. beta 2-microglobulin concentration was found to be raised (P < 0.001) in 30 women with postmenopausal osteoporosis as compared with 30 normal women of similar age; tartrate-resistant acid phosphatase concentration also was raised (P < 0.001), and total body bone mineral content was decreased (P < 0.001). Linear regression analysis revealed a highly negative correlation result between total body bone mineral content and beta 2-microglobulin (r = 0.577, P < 0.001), and a positive correlation result between beta 2-microglobulin and tartrate-resistant acid phosphatase concentration (r2 = 0.806, P < 0.001). These findings, and the stimulatory effect of beta 2-microglobulin on osteoclastic and osteoblastic activity, suggest that beta 2-microglobulin may play an important role as a local regulatory factor in the pathogenesis of postmenopausal osteoporosis.

Acid Phosphatase↗
PubMed1993

Age-related differences in total and regional bone mass: a cross-sectional study with DXA in 429 normal women.

Total body bone mineral content (TBBMC), total body bone mineral density (TBBMD) and regional bone mineral content (BMC) and density (BMD) were assessed by dual-energy X-ray absorptiometry (DXA) in 429 normal women aged 15-83 years, of whom 242 were premenopausal and 187 postmenopausal. The population was divided into 5-year age groups. In the premenopausal women no changes in TBBMC, TBBMD or regional BMC and BMD were observed with age, and TBBMC and TBBMD values correlated well with body weight (p < 0.001). Postmenopausal women showed an overall reduction in bone mass (p < 0.001), more marked at the axial level than peripherally (1.6% vs. 0.8%/year). The values of TBBMC and TBBMD correlated well with chronological age, time since the onset of menopause and body weight (p < 0.001). In these women age did not correlate with body weight, which suggests that postmenopausal bone mass loss depends more on chronological age and time since the onset of menopause than on other variables. The stability observed in bone mass values from ages 15-19 to menopause highlights the importance of stimulating the acquisition of an appropriate peak bone mass in women before adolescence begins.

Absorptiometry, Photon↗
PubMed1993

The relationship of total body bone mineral (TBBMC) to anthropometric variables in postmenopausal women, and contribution of chronological age and years since menopause to TBBMC loss.

Dual energy X-ray absorptiometry measurements of total body bone mineral content (TBBMC), fat body mass (FBM) and fat mass percentage (%FM), lean body mass (LBM) and body weight (BW) were performed on 168 normal postmenopausal females. They were matched regarding life style and habits and had body mass index under 30. Their TBBMCs were correlated with these measurements, with chronological age (CA) and with the number of years since menopause (YSM). There was no correlation between TBBMC and %FM and LBM, but there was with BW (p < 0.001). There was a significant and negative correlation (r = -0.453, p < 0.001) between TBBMC and CA and to a higher range (r = -0.697, p < 0.001) with YSM. Menopausal females over 60 (n = 87) presented less bone mass than younger females (n = 81) (p < 0.01). These data suggest that regarding TBBMC, menopausal onset is a more important factor in bone mass loss, which persists rather markedly even during periods of time far from menopause and that TBBMC depends more on BW than on LBM and FM in women.

Adipose Tissue↗
PubMed1993

Bone mineral content and anthropometric variables in men: a cross-sectional study in 324 normal subjects.

Total body bone mineral content (TBBMC), total body bone mineral density (TBBMD), and regional bone mineral content (BMC) were determined with dual energy X-ray absorptiometry and correlated with different anthropometric variables in 324 normal male subjects aged 15 to 85 years, in order to obtain further knowledge of the controversial course of bone mass in males. These subjects showed increased TBBMC and TBBMD up to the age of 25-29 years. A positive and significant (p < 0.001) correlation was observed between TBBMC and TBBMD and with BMC with age (p < 0.001), as well as between age and body weight (p < 0.001) and between the latter and body fat (p < 0.001). Age did not correlate with weight or TBBMC, TBBMD, and regional BMC in subjects older than 29 years, while a significant and positive correlation between body weight and muscle mass was observed with bone mass (p < 0.001). By multiple regression analysis, TBBMC was significantly independent of fat-free mass (FFM) and lean body mass (LBM) (p < 0.01). These findings led us to point out that bone mass increases until the age of 29 years and that changes depend more on weight that on age in men. The rate of bone mass loss with age was 0.23%, that of soft tissue 0.35%, while fat mass increased 0.7% per year.

Adolescent↗