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Biomedical subjects

D Slosman

Publications and source records attributed to D Slosman.

At least 37 records · Page 2Linked to original sources
PubMed1996

Lack of effects of recombinant growth hormone on muscle function in patients requiring prolonged mechanical ventilation: a prospective, randomized, controlled study.

OBJECTIVE: To evaluate the benefit of recombinant human growth hormone administration on muscle strength and duration of weaning in critically ill patients undergoing prolonged mechanical ventilation. DESIGN: Prospective, randomized, controlled, single-blind study. SETTING: Intensive care unit. PATIENTS: Twenty patients requiring > or = 7 days of mechanical ventilation for acute respiratory failure. INTERVENTION: Random assignment to receive either 0.43 IU (approximately 0.14 mg) recombinant growth hormone/kg body weight/day (treated group), or saline (nontreated group) for 12 days. MEASUREMENTS AND MAIN RESULTS: Nutritional support was guided by indirect calorimetry. Cumulative nitrogen balance was positive throughout the study period in the treated group 17.3 (44.9 +/- 17.3[SEM] g/12 days) vs. the nontreated group (-65.8 +/- 11.8 g/12 days) (p<.0001). Despite similar initial plasma concentrations, recombinant growth hormone supplementation resulted in marked increases in growth hormone, insulin like growth factor-1, and insulin concentrations (p<.05, .02, and .0001, respectively, vs. nontreated group). Body impedance determined net fat-free mass increased in the treated group (0.8 +/- 0.6 kg) vs. the nontreated group (-1.1 +/- O.5 kg) (p<.03). Initial peripheral muscle function, assessed by computer-controlled electrical stimulation of the adductor pollicis, was similarly lower in treated and nontreated groups than sex and age-matched normal controls, and decreased further during the study period. Arterial blood gases, cumulative total mechanical ventilation time, and number of hrs/day of mechanical ventilation during weaning were similar in both patient groups. Only three of the ten patients in each group were weaned from mechanical ventilation by day 12. CONCLUSIONS: Daily administration of recombinant growth hormone in mechanically ventilated patients with acute respiratory failure promotes a marked nitrogen retention. However, this reaction is accompanied neither by an improvement in muscle strength nor by a shorter duration of ventilatory supports.

Acute Disease↗
PubMed1996

Recombinant human growth hormone in chronic and acute respiratory insufficiency.

Chronic respiratory insufficiency leads to protein-calorie malnutrition (PCM). PCM results in increased morbidity (e.g., infection), which in turn promotes further body wasting. The latter leads to respiratory muscle dysfunction and acute respiratory failure. Nutritional support alone is generally insufficient to counterbalance this hypoxemic and stress-related muscle catabolism. Recombinant human growth hormone (rhGH) can preserve or replenish nitrogen reserves, mostly contained in body muscle mass. It was hypothesized that rhGH, through its ability to improve muscle mass and function, could be a valuable therapeutic adjunct in both chronic and acute respiratory insufficiency. The results are controversial, and the beneficial effects of rhGH in patients with chronic and acute respiratory insufficiency, in terms of improvement of respiratory function, morbidity, and quality of life, remain to be shown. Well-designed studies, specifically targeting these end points as well as cost-effectiveness, are needed to better define the place of rhGH in the nutritional support of these patients.

Acute Disease↗
PubMed1995

The role of dual energy X-ray absorptiometry of lumbar spine and proximal femur in the diagnosis and follow-up of osteoporosis.

Dual energy x-ray absorptiometry techniques have been validated for the quantitative assessment of bone mass at two skeletal sites particularly at risk of osteoporotic fracture, i.e., lumbar spine and proximal femur. These measurements assess areal bone mineral density (BMD), which integrates the size of the bone and its thickness, as well as the true volumetric density. Areal density provides useful information relative to fracture risk, since there is an inverse relationship between incidence of osteoporotic fractures and areal BMD. Although lumbar spine BMD measurements by a lateral view could offer the advantage over conventional anteroposterior projection of avoiding osteophytes and posterior element osteoarthritis, it does not seem to be superior in diagnostic sensitivity, except possibly for corticosteroid-induced bone loss. Femoral neck BMD appears to be a significantly better predictor of fracture of the proximal femur. Since this measurement does not appear to be influenced by osteoarthritis, it would be the most suitable for the diagnosis of osteoporosis in the elderly. However, the potential for error in terms of both accuracy and precision for dual x-ray absorptiometry measurements of lumbar spine and proximal femur emphasizes the need for strictly controlled conditions of measurement.

Absorptiometry, Photon↗
PubMed1995

Vitamin-D-receptor-gene polymorphisms and change in lumbar-spine bone mineral density.

Common vitamin-D-receptor (VDR) gene allelic variants predict bone mineral density. We analysed VDR alleles and rate of change of lumbar-spine bone mineral density over 18 months in 72 elderly subjects. 9 BB homozygotes lost bone mineral density but 26 homozygotes for the alternative genotype (bb) did not (mean change -2.3 [SE 1.0] vs 0.9 [0.7]% per year, p < 0.05), irrespective of calcium intake. Among 37 heterozygotes (Bb), however, change in bone mineral density correlated with calcium intake (r = 0.35, p < 0.03). This association between a genetic marker and rate of bone loss in the elderly suggests that the effect of calcium intake on maintenance of bone mass could relate to VDR gene polymorphisms.

Aged↗
PubMed1995

[Peak bone mass: facts and uncertainties].

Peak bone mass, which can be defined as the amount of bony tissue present at the end of the skeletal maturation, is an important determinant of osteoporotic fracture risk in adulthood. The techniques of single or dual energy absorptiometry measure the so-called "areal" or "surface" bone mineral density (BMD), a variable which has been shown to be directly related to bone strength. During puberty the gender difference in bone mass becomes expressed. This difference appears to be essentially due to a more prolonged bone maturation period in males than in females, with a larger increase in bone size and cortical thickness, as there is no significant sex difference in the volumetric trabecular density at the end of pubertal maturation. At the beginning of the 3rd decade, there is a large variability in the normal values of areal BMD in axial and appendicular skeleton. This large variance, which is observed at sites particularly susceptible to osteoporotic fractures in adulthood, such as lumbar spine and femoral neck, is barely reduced after correction for statural height, and does not appear to substantially increase during adult life. It is generally accepted that peak bone mass at any skeletal site is attained in both sexes during the mid-thirties. However, recent studies indicate that in healthy caucasian females, bone mass accumulation can virtually be completed before the end of the second decade, for both lumbar spine and femoral neck. Several variables are supposed to influence bone mass accumulation during growth: heredity, sex, diet components, endocrine factors, mechanical forces, and exposure to risk factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Magnetic resonance imaging with superparamagnetic iron oxide particles to evaluate hepatic macrophage-monocytic phagocytosis after arterial devascularization in minipigs.

RATIONALE AND OBJECTIVES: We examined the effects of arterial ischemia on the phagocytic activity of the hepatic macrophage-monocytic phagocytic system (MMPS). METHODS: Six minipigs were studied before and 24 hr after complete arterial devascularization of the liver. Magnetic resonance (MR) imaging was performed at 1.5 T using superparamagnetic iron oxide (SPIO) particles (18 mumol Fe/kg body weight) as an MMPS-specific contrast agent. Hepatobiliary scintigraphy, measurements of serum liver enzymes, and histology also were obtained. RESULTS: On MR imaging, the postcontrast-to-precontrast ratios of the arterially devascularized livers were significantly higher than the corresponding baseline values (p < .01). The greatest difference (52%) between the baseline and the postoperative values was observed on gradient-echo (GE) images. Scintigraphy, laboratory analyses, and histology results indicate that the MR imaging findings were probably predominantly attributable to a reduction in phagocytic activity of the hepatic MMPS. CONCLUSION: SPIO particles have already proved useful for improving detection of liver neoplasms on MR imaging, but they also may provide a novel way of evaluating the function of the hepatic MMPS in liver diseases.

Animals↗
PubMed1994

Effects of calcium supplements on femoral bone mineral density and vertebral fracture rate in vitamin-D-replete elderly patients.

The efficacy of calcium (Ca) in reducing bone loss is debated. In a randomized placebo-controlled double-masked study, we investigated the effects of oral Ca supplements on femoral shaft (FS), femoral neck (FN) and lumbar spine (LS) bone mineral density (BMD), and on the incidence of vertebral fracture in vitamin-D-replete elderly. Ninety-three healthy subjects (72.1 +/- 0.6 years) were randomly allocated to three groups receiving 800 mg/day Ca in two different forms or a placebo for 18 months. Sixty-three patients (78.4 +/- 1.0 years) with a recent hip fracture were allocated to two groups receiving the two forms of Ca without placebo. FS BMD changes in Ca-supplemented non-fractured women were significantly different from those in the placebo group (+0.6 +/- 0.5% v -1.2 +/- 0.7%, p < 0.05). There was no difference in effect between the two forms of Ca. The changes of +0.7 +/- 0.8% v -1.7 +/- 1.6% in FN BMD of Ca-supplemented women and the placebo group did not reach statistical significance. In fractured patients, FS, FN and LS BMD changes were -1.3 +/- 0.8, +0.3 +/- 1.6 and +3.1 +/- 1.2% (p < 0.05 for the last). The rate of new vertebral fractures was 74.3 and 106.2 fractures per 1000 patient-years in Ca-supplemented non-fractured subjects and in the placebo group, respectively, and 144.0 in Ca-supplemented fractured patients. Thus, oral Ca supplements prevented a femoral BMD decrease and lowered vertebral fracture rate in the elderly.

Administration, Oral↗
PubMed1994

Peak bone mass.

Peak bone mass, which can be defined as the amount of bony tissue present at the end of the skeletal maturation, is an important determinant of osteoporotic fracture risk. Measurement of bone mass development. The bone mass of a given part of the skeleton is directly dependent upon both its volume or size and the density of the mineralized tissue contained within the periosteal envelope. The techniques of single-1 and dural-energy photon or X-ray absorptiometry measure the so-called 'areal' or 'surface' bone mineral density (BMD), a variable which has been shown to be directly related to bone strength. Bone mass gain during puberty. During puberty the gender difference in bone mass becomes expressed. This difference appears to be essentially due to a more prolonged bone maturation period in males than in females, with a larger increase in bone size and cortical thickness. Puberty affects bone size much more than the volumetric mineral density. There is no significant sex difference in the volumetric trabecular density at the end of pubertal maturation. During puberty, the accumulation rate in areal BMD at both the lumbar spine and femoral neck levels increases to four- to sixfold over a 3- and 4-year period in females and males, respectively. Change in bone mass accumulation rate is less marked in long bone diaphyses. There is an asynchrony between the gain in statural height and bone mass growth. This phenomenon may be responsible for the occurrence of a transient period of a relative increase in bone fragility that may account for the pattern of fracture incidence during adolescence.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1994

Applicability of decision analysis to everyday clinical practice: a controlled feasibility trial.

OBJECTIVE: To determine whether decision analysis is applicable to routine management of suspected pulmonary embolism in an emergency care setting. DESIGN: Controlled feasibility trial. SETTING: Emergency center of a university hospital. PATIENTS: Outpatients (n = 84) admitted with clinical and scintigraphic evidence of pulmonary embolism. INTERVENTIONS: Patients were treated either with the usual clinical work-up for pulmonary embolism (control group) or using a decision analysis model with three options: no action: angiography followed by treatment if positive; treatment without angiography. RESULTS: All six senior residents in the decision analysis group agreed to fully participate for the 16 months of the study. Summarizing the decision analysis model in a graph was critical to obtain acceptance from all the physicians. Decision analysis (n = 43) and control (n = 41) patients underwent similar numbers of angiographies. However, angiographies for patients who had intermediate clinical probabilities of pulmonary embolism, between 25 and 75%, were more frequent in the decision analysis group (9/13 = 69%) than in the control group (7/20 = 35%). Agreement between clinical probability and lung-scan result was stronger in the decision analysis group. CONCLUSIONS: Decision analysis was successfully used to manage all patients suspected of having pulmonary embolism admitted to an emergency center during the 16-month trial. There was no insuperable obstacle to acceptance of clinical decision analysis by the physicians. Decision analysis may have resulted in a better discrimination between low and intermediate clinical probabilities of pulmonary embolism.

Adult↗
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↗