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Biomedical subjects

D Slosman

Publications and source records attributed to D Slosman.

At least 55 records · Page 3Linked to original sources
PubMed1994

Contribution of D-dimer plasma measurement and lower-limb venous ultrasound to the diagnosis of pulmonary embolism: a decision analysis model.

The Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) study has shown that clinical evaluation and lung scanning may substantiate or exclude pulmonary embolism with reasonable probability in approximately half of the patients in whom it is suspected; for the remainder, pulmonary angiography is considered the gold standard diagnostic test. We performed a decision analysis to assess the potential of two noninvasive tests, D-dimer plasma measurement and lower-limb B-mode venous ultrasound, for reducing the number of pulmonary angiograms necessary to diagnose pulmonary embolism. Our decision model addresses hypothetical patients in the emergency ward with suspected pulmonary embolism and abnormal lung scan results. Results show that D-dimer measurements of less than 500 micrograms/L could be used reliably to exclude pulmonary embolism in patients with an abnormal but not high-probability (inconclusive) lung scan. D-dimer measurements of greater than 500 micrograms/L have no positive predictive value for pulmonary embolism and should be followed by ultrasound, which may replace pulmonary angiography when it discloses deep venous thrombosis. Pulmonary angiography should be performed when ultrasound is negative because of its presumably low sensitivity for deep venous thrombosis in patients with pulmonary embolism. A D-dimer measurement of less than 500 mu/L does not exclude pulmonary embolism in patients with a high clinical suspicion of pulmonary embolism. On the basis of the results of the PIOPED study, we calculated that the combination of D-dimer measurement and ultrasound might reduce the requirement for pulmonary angiography by one third among patients with inconclusive scan results and intermediate clinical probability of pulmonary embolism.

Angiography↗
PubMed1994

Effects of oral calcitriol on bone mineral density in patients with end-stage renal failure.

Evolution of bone mineral density (BMD) at various skeletal sites and the influence of calcitriol on BMD are still poorly documented in patients with terminal renal failure. Using dual photon absorptiometry, we investigated the changes in BMD at the levels of lumbar spine, femoral neck and midfemoral shaft in 21 patients with end-stage renal failure (ESRF) treated with calcitriol (mean dosage +/- SEM: 0.21 +/- 0.02 microgram/day) and compared them to 25 patients with ESRF but not treated with calcitriol (control group) over a period of 20.3 +/- 1.5 and 17.2 +/- 1.2 months, respectively. Lumbar spine BMD increased by 7.7 +/- 3.2%/year in the treated group and decreased by 2.5 +/- 1.3%/year in the control group (P < 0.005). Femoral shaft BMD increased more in treated than in control group (+ 6.7 +/- 2.3 vs. + 1.4 +/- 2.0%/year; P < 0.05) and femoral neck BMD remained stable. PTH levels increased by 92 +/- 121 and 1033 +/- 254 pmol/year (P < 0.01) in the treated group and the controls, respectively. Osteocalcin changes were -2.7 +/- 3.7 and +20.1 +/- 11.7 micrograms/liter (P < 0.05) per year in the same groups. These results indicate that low doses of oral calcitriol in patients with end-stage renal failure were associated with an increase in BMD at the levels of lumbar spine and femoral shaft, and with a stabilization of serum PTH and osteocalcin concentrations.

Administration, Oral↗
PubMed1994

Early hydrogen peroxide-induced pulmonary endothelial cell dysfunction: detection and prevention.

OBJECTIVES: To determine a) whether hydrogen peroxide-induced, early lung endothelial cell dysfunction can be detected in an isolated, perfused, rat lung model; and b) whether the organic phosphothioate N-(2-mercaptoethyl)-1,3-propanediamine, which protects cells in culture against hydrogen peroxide-mediated damage, can exert the same protection in this model. DESIGN: Intervention study; before-after trial. SETTING: Research laboratory. MODEL: Isolated, perfused, rat lung model. INTERVENTION: Continuous hydrogen peroxide infusion at increasing concentrations and infusion times, preceded or not by a N-(2-mercaptoethyl)-1,3-propanediamine infusion. MEASUREMENTS AND MAIN RESULTS: Early pulmonary endothelial cell alterations, assessed by the lung extraction (% extraction) of 123I-metaiodobenzylguanidine. Permeability edema by % extraction of 125I-human serum albumin and the lung dry-to-wet weight ratio. Control experiments: % extraction-123I-metaiodobenzylguanidine: 21.7 +/- 3.8% (n = 7). With increasing concentrations of hydrogen peroxide (0.025, 0.125, 0.5, and 2 mmol), % extraction-123I-metaiodobenzylguanidine was progressively depressed (n = 28, ANOVA, p < .05), significantly decreased from controls at 2 mmol (10.2 +/- 5.0%, n = 7, p < .05). When the 2-mmol hydrogen peroxide infusion was preceded by the N-(2-mercaptoethyl)-1,3-propanediamine (2 mmol) infusion, % extraction-123I-metaiodobenzylguanidine (19.9 +/- 2.9%, n = 5) was not significantly different from controls (n = 7) and was significantly greater than after the 2-mmol hydrogen peroxide infusion alone (8.7 +/- 7.4%, p < .05, n = 8). In all experiments, % extraction of human serum albumin ratio and dry-to-wet weight ratio were not significantly different from that of controls. CONCLUSIONS: a) Hydrogen peroxide-induced lung endothelial cell dysfunction was detected at an early stage, before any permeability defect appeared; b) N-(2-mercaptoethyl)-1,3-propanediamine protected against such damage.

Amifostine↗
PubMed1993

Effects of the bisphosphonate tiludronate on bone resorption, calcium balance, and bone mineral density.

Bone resorption inhibitors, such as bisphosphonates, are potentially useful in treatments aimed at increasing bone mass. Among bisphosphonates, tiludronate has proven efficacious in preventing bone loss in postmenopausal women. However, it is not clearly established whether bisphosphonates are more potent when given intermittently or continuously. We investigated the effects of tiludronate on (1) retinoid-stimulated bone resorption in thyroparathyroidectomized rats, (2) calcium balance in intact rats, and (3) bone mineral density (BMD) as measured by dual-energy x-ray absorptiometry at the levels of the lumbar spine, tail, and tibia in 6-month-old rats made osteoporotic by ovariectomy (OVX), in which an intermittent cyclic schedule of treatment was compared to continuous administration. Tiludronate induced a dose-dependent decrease in retinoid-stimulated bone resorption. It increased the intestinal absorption and body retention of calcium. In OVX rats it caused a time- and dose-dependent increase in BMD at the level of the three investigated sites, the effects being maintained for at least 8 weeks after the end of therapy. Continuous and intermittent cyclic regimens appeared to induce similar increases in BMD. These results indicate that tiludronate is efficacious in decreasing bone resorption and increasing calcium balance and bone mineral density in rats.

Animals↗
PubMed1993

Relationship between bone mineral density and dietary intakes in the elderly.

Dietary protein and/or calorie insufficiencies represent an important problem in elderly patients. The biological and clinical implications, and particularly the influence on bone mass of undernutrition in the elderly, have not been completely defined, although several studies have demonstrated a high prevalence of dietary insufficiencies in patients with a recent fracture of the proximal femur. In the present study the relationship between dietary intakes, physical performance and bone mineral density (BMD) was examined in hospitalized elderly patients. The study comprised 74 patients (48 women, mean age 82 years; and 26 men, mean age 80 years) who were hospitalized for various medical indications. They were divided into two groups according to their dietary protein intakes, evaluated during the first 28 days in hospital while on a regular diet. The first group consisted of 26 patients (14 women and 12 men) whose protein intake was equal to or greater than 1 g per kilogram of ideal body weight. The second group consisted of 48 patients (34 women and 14 men) who consumed less than 1 g of protein per kilogram of ideal body weight. The two groups differed also in their energy, carbohydrate, lipid and calcium intakes. Patients in the group with the higher protein intake displayed higher BMD at the level of the femoral neck as measured by dual-photon absorptiometry. The men in this group also had higher lumbar spine BMD. After 4 weeks in hospital the women with a higher protein intake had significantly enhanced bicipital and quadricipital muscle strength and better performance as indicated by the increased capacity to climb stairs.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

IGF-I and pamidronate increase bone mineral density in ovariectomized adult rats.

Effects induced by insulin-like growth factor I (IGF-I) and/or the bisphosphonate pamidronate (APD) on bone mineral density (BMD) of the lumbar spine and proximal and midshaft tibia were studied in adult rats made osteopenic by ovariectomy, using dual-energy X-ray absorptiometry. IGF-I, which was administered by osmotic minipumps implanted subcutaneously for 6 wk, caused a dose-dependent increase of BMD at the three investigated sites. A 4-wk course of IGF-I, followed by intermittent cyclical APD administration, induced significant increases of BMD at the levels of spine and proximal tibia. At midshaft tibia, where cortical bone predominates, BMD was increased by IGF-I only. In conclusion, IGF-I increased BMD at sites with trabecular and/or cortical bone, whereas the APD influence was mainly detectable in the former site only.

Absorptiometry, Photon↗
PubMed1993

Bone mineral density in patients with end-stage renal failure.

Renal osteodystrophy is a well-recognized complication of chronic renal failure (CRF) and is associated with a marked morbidity. Bone mineral density (BMD) has been shown to be the best predictor of fracture risk in different circumstances. In this cross-sectional study, we measured BMD using dual photon absorptiometry at three skeletal sites of functional importance such as the lumbar spine (LS), the femoral shaft (FS) and the femoral neck (FN) in 106 patients with end-stage renal failure (11 predialysis patients and 95 patients on maintenance dialysis). These skeletal sites are characterized by various relative amounts of trabecular and cortical bone. The results indicate that decreased bone mass was detectable in all skeletal sites before the beginning of dialysis and that BMD was negatively related to dialysis duration in LS and FS. Nevertheless, the deleterious effects of renal osteodystrophy were more pronounced at the FS level, where cortical bone is predominant. A separate analysis of BMD in both sexes revealed that females presented a more important bone loss in both cortical and trabecular bone than males. We did not find any significant difference in BMD at the three measured sites between patients on continuous ambulatory peritoneal dialysis and on regular hemodialysis. This study emphasizes the need to pay more attention to the prevention of bone loss in patients on CRF before the start of dialysis therapy, and to the fact that the female population might display a more pronounced susceptibility to bone loss.

Absorptiometry, Photon↗
PubMed1993

[Eating behavior and bone mineral density in young women marathon participants].

Although reduced gonadal steroid hormone concentration appear to play a major role in lower trabecular bone density (BMD) in female marathon runners, dietary deficiencies and eating behaviors may also affect BMD. To investigate that possibility, dietary patterns and BMD were examined in 27 female regular marathon runners classified as eumenorrheic (8), amenorrheic (10) and under oral contraception (9). The results show a significant lower BMD in amenorrheic athletes but no dietary deficiencies. These results suggest that the eating behavior don't play any role in the lower BMD of our athletes.

Adolescent↗
PubMed1992

[Bone mineral density of the lumbar spine, the femoral neck and femoral diaphysis in a Genevan population sample].

Bone mineral density (BMD) was measured by dual photon absorptiometry in the lumbar spine, femoral neck and midfemoral shaft in 209 women and 165 men aged 20 to 98 years recruited among the Geneva population. The prevalence of various factors (life style, calcium intake, body weight) which may be associated with a higher risk of osteoporosis was evaluated. Between the different skeletal sites, BMD was closely correlated. Nevertheless, BMD at one site failed to accurately predict BMD of another site. In each age class, BMD was dispersed over a wide range. Women and men had similar lumbar spine BMD. In women, BMD decreased after the fifth decade by 1.3, 1.0 and 2.6% year in the lumbar spine and femoral neck and shaft, respectively. Daily calcium intake from dairy products was 430 g and 750 g in women and men, respectively. Femoral shaft BMD was positively correlated with calcium intake. These BMD values obtained in a sample of the normal Geneva population should be of major help for the diagnosis of osteoporosis.

Adult↗
PubMed1992

Sequential and precise in vivo measurement of bone mineral density in rats using dual-energy x-ray absorptiometry.

In the design of new strategies for the treatment of osteoporosis, noninvasive, precise, and sensitive bone mass measurement capable of detecting changes over short periods of time in small animals is essential. Most of the models described thus far require the sacrifice of the animals and/or display low reproducibility. Using a dual-energy x-ray absorptiometer (DEXA; Hologic QDR-1000) in an ultrahigh-resolution mode, we measured bone mineral density (BMD) in rats at the levels of lumbar spine (L1-4), proximal tail (caudal vertebrae C2-4), and tibia. Accuracy was evaluated by measuring the mineral content of bone powder capsules (within the range of rat vertebrae BMD), under 0.5-3 cm water to mimic variations in soft tissue thickness. The bone powder capsule mineral content was highly correlated with chemically determined hydroxyapatite content (r = 0.999). In vivo reproducibility was evaluated by calculating the coefficient of variation (CV = 100 x SD/mean) of four to six BMD measurements, each time with repositioning, in seven rats (220-500 g body weight). CV was 1.36 +/- 0.32% (x +/- SD) for lumbar spine, 0.66 +/- 0.50% for proximal tail, and 1.12 +/- 0.45% for tibia. The ability to detect BMD changes was investigated by measuring BMD before and every 4 weeks after ovariectomy (OVX) in 270 g rats, pair fed during the whole experiment. Compared with sham-operated control animals, a highly significant difference in lumbar spine BMD was observed 4 weeks after OVX, which reached a maximum by 8 weeks and remained stable thereafter. At the level of the proximal tibia, the difference was maximal 4 weeks after OVX.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1992

Benefits of oral protein supplementation in elderly patients with fracture of the proximal femur.

Malnutrition has been often suggested as contributing to both the high incidence of hip fracture in elderly people and its complications. In a recent prospective controlled randomized study, the clinical outcome of elderly patients with osteoporotic fracture of the proximal femur (hip fracture) improved by giving a simple oral dietary supplement. This study, however, did not prove that protein was responsible for the clinical improvement since the supplement also contained vitamins and minerals. We addressed this question by comparing the clinical outcome and bone mineral density (BMD) changes in elderly patients with hip fracture, receiving two different dietary supplements with different protein contents. Sixty-two patients (mean age 82) admitted into the orthopedic ward for fracture of the proximal femur were randomized into two groups. One group (n = 33) received 250 ml/day of an oral nutritional supplement containing protein (20.4 g), mineral salts (Ca: 0.525 g) and vitamins A = 750 IU; D3 = 25 IU) for a mean of 38 days. A control group (n = 29) received the same supplement dose, but with no protein, for the same period of time. The clinical course was significantly better in the group receiving protein, with 79% having a favorable course as compared to 36% (p less than 0.02) in the control group during the stay in the recovery hospital. The rate of complications and deaths was also significantly lower in the protein-supplemented vs the control group (52 vs 80%, p less than 0.05) 7 months after hip fracture. The median hospital stay was significantly lower in the protein-supplemented group (69 vs 102 days, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1992

Longitudinal monitoring of bone mass accumulation in healthy adolescents: evidence for a marked reduction after 16 years of age at the levels of lumbar spine and femoral neck in female subjects.

The amount of skeletal mass acquired during adolescence is one of the most important determinants for the risk of postmenopausal and involutional osteoporosis. In both sexes, a large variance in bone mineral density (BMD) and content (BMC) is observed among healthy individuals at the beginning of the third decade. To determine the crucial pubertal years during which bone mass accumulation mainly occurs, we longitudinally monitored the gain in BMD/BMC at clinically important sites, such as lumbar spine and femoral neck, with respect to osteoporotic fracture risk. The changes in BMD (grams per cm2) and BMC (grams) were determined at 1-yr intervals at the level of lumbar spine vertebrae (L2-L4), femoral neck, and midfemoral shaft, using dual energy x-ray absorptiometry (Hologic QDR 1000), in 198 healthy adolescents (98 females and 100 males), aged 9-19 yr. Mean daily energy and calcium intakes, height, weight, and body mass index of the studied cohort were within the normal range for age. In females, the increment rate in BMD/BMC was particularly pronounced over a 3-yr period, i.e. from 11-14 yr of age. This increment dramatically fell after 16 yr and/or 2 yr after menarche. The mean gains in lumbar, femoral neck, and midfemoral shaft BMD were not statistically significant between 17-20 yr. In males, the gain in BMD/BMC was particularly high over a 4-yr period, i.e. from 13-17 yr. Then the increment rate markedly declined, but remained significant between 17-20 yr for L2-L4 BMD/BMC and midfemoral shaft BMD. In contrast, no significant increase was observed for femoral neck BMD. An impressive interindividual variation was observed between the yearly height increment and the bone mass accumulation. The bone mass-height gains relationship during puberty evolved according to a loop pattern, with maximal variance at Tanner stages P3-P4. This longitudinal study delineates the crucial pubertal years during which the skeletal mass accumulates at high, but various, rates at skeletal sites where the consequences of the osteoporosis are particularly dramatic. Furthermore, the results indicate that in a cohort of healthy females with apparently adequate intakes of energy and calcium, bone mass accumulation is drastically reduced by 16 yr of age in both lumbar spine and femoral neck.

Absorptiometry, Photon↗
PubMed1991

Measurement of D-dimer in plasma as diagnostic aid in suspected pulmonary embolism.

The potential of plasma measurement of D-dimer (DD), a specific derivative of crosslinked fibrin, for diagnosis or exclusion of pulmonary embolism was investigated in a prospective series of 171 consecutive patients who attended an emergency department with suspected pulmonary embolism. The diagnosis was made or excluded by means of a clinical decision-making process which included clinical evaluation, ventilation-perfusion (VQ) lung scan, and, as indicated, pulmonary angiography, venography, or non-invasive examination of the leg veins. Pulmonary embolism was diagnosed by this process in 55 (32%) of 170 patients with sufficient data. All but 1 of these 55 patients had a DD concentration of 500 micrograms/l or above. The sensitivity and specificity of this cutoff concentration for the presence of pulmonary embolism were 98% and 39%, respectively, which give positive and negative predictive values of 44% and 98%. Among the 115 patients (68%) who had inconclusive VQ scans, 31 were diagnosed as having pulmonary embolism. 29 of the remaining 84 patients without pulmonary embolism had DD concentrations below 500 micrograms/l, which means that further diagnostic procedures could have been avoided in a quarter of the patients with inconclusive VQ scans. The sensitivity of the plasma measurement of DD remained high even 3 and 7 days after presentation (96% and 93%). Plasma measurement of DD therefore has a definite place in the diagnostic procedure for suspected acute pulmonary embolism in attenders at emergency departments: a concentration below 500 micrograms/l rules out the diagnosis.

Adolescent↗
PubMed1991

Preferential low bone mineral density of the femoral neck in patients with a recent fracture of the proximal femur.

Bone mass is an important determinant of resistance to fractures. Whether bone mineral density (BMD) in subjects with a fracture of the proximal femur (hip fracture) is different from that of age-matched controls is still debated. We measured BMD of the femoral neck (FN) on the opposite side to the fracture, as well as femoral shaft (FS) and lumbar spine (LS) BMD by dual-photon absorptiometry in 68 patients (57 women and 11 men, mean age 78.8 +/- 1.0) 12.4 +/- 0.8 days after hip fracture following a moderate trauma. These values were compared with BMD of 93 non-fractured elderly control subjects (82 women and 11 men), measured during the same period. As compared with the controls, FN BMD was significantly lower in fractured women (0.592 +/- 0.013 v. 0.728 +/- 0.014 g/cm2, P less than 0.001) and in fractured men (0.697 +/- 0.029 v. 0.840 +/- 0.052, P less than 0.05). Expressed as standard deviations above or below the mean BMD of age and sex-matched normal subjects (Z-score), the difference in FN BMD between fractured women and controls was highly significant (-0.6 +/- 0.1 v. +0.1 +/- 0.1, P less than 0.001). As compared with mean BMD of young normal subjects, BMD was decreased by 36.9 +/- 1.4 and 22.4 +/- 1.5% (P less than 0.001) in fractured and control women, respectively. There was no significant difference between FN BMD of 33 women with cervical and 24 with trochanteric hip fractures (0.603 +/- 0.017 v. 0.577 +/- 0.020). FN BMD was lower than 0.705 g/cm2 in 90% of fractured women.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Critical years and stages of puberty for spinal and femoral bone mass accumulation during adolescence.

Maximizing peak bone mass is advocated as a way to prevent osteoporosis. As a prerequisite to the elaboration of any preventive program aimed at maximizing peak bone mass, it is important to determine how the rate of skeletal growth at clinically relevant sites, such as lumbar spine and femoral neck, proceeds in relation to age and pubertal stages in both sexes. Bone mass was assessed in 207 healthy caucasian boys and girls, aged 9-18 yr. Bone mineral density (BMD; grams per cm2) and content (BMC; grams) were determined in lumbar spine (L2-L4), femoral neck (FN), and midfemoral shaft (FS), using dual energy x-ray absorptiometry. Bone variables were correlated with both chronological age and pubertal stage, and compared with young adult (20-35 yr) reference values. The main results are: 1) in males, compared to females, there was a marked age-related delay in L2-L4 BMD or BMC increase, but no delay was observed in relation to pubertal stages; 2) at the end of the rapid growth spurt, trends for higher mean values in males were observed for L2-L4 BMC, FN BMD, and particularly FS BMD, but no sex difference was observed for L2-L4 BMD; 3) in females, but not in males, a dramatic reduction in bone mass growth was observed after 15 yr of age, particularly for L2-L4 BMD/BMC and FN BMD. This sharp reduction occurred between the second and fourth years after menarche. In the 14- to 15-yr-old female group, BMD in L2-L4, FN, and FS corresponded to 99.2%, 105.1%, and 94.1%, respectively, and BMC in L2-L4 to 97.6% of the mean values recorded in 20- to 35-yr-old women. In conclusion, this cross-sectional study indicates that during pubertal development, major differences are observed in bone mass growth according to sex and skeletal site. Whereas in males bone mass at different skeletal sites continues to increase substantially between 15-18 yr, skeletal mass growth appears to dramatically slow down at the levels of both lumbar spine and FN at 15-16 yr of age in female adolescents. This suggests that the generally accepted notion that in both males and females bone mass continues to substantially accumulate at all skeletal sites until the fourth decade may not be a constant in human physiology.

Absorptiometry, Photon↗
PubMed1991

[Value of the plasma measurement of D-dimers in the diagnosis of venous thromboembolism].

Plasma measurement of D-dimers (DD), which are fibrin-specific degradation products, progressively replaces the cumbersome dosage of fibrinogen degradation products (FDP's) in serum for diagnosis and follow-up of consumption coagulopathies, for diagnosis of prethrombotic states and, potentially, for the control of the efficacy of antithrombotic therapies. Moreover, when the ELISA technique is used, this measurement may be very useful in the diagnosis approach of venous thromboembolic disease. In the present review, data are presented which strongly support the view that a low level of plasma D-dimers (less than 500 micrograms/L when using the ELISA from Stago) allows to exclude the diagnosis of deep venous thrombosis or pulmonary embolism with predictive values of 94 % and 100 % respectively. It is suggested that such a diagnostic potential might be very useful in the group of patients with inconclusive perfusion-ventilation scintigraphy (low or indeterminate probability of pulmonary embolism) which represent about 50 % of the patients with suspected pulmonary embolism.

Enzyme-Linked Immunosorbent Assay↗