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Biomedical subjects

R Lew

Publications and source records attributed to R Lew.

At least 37 records · Page 2Linked to original sources
PubMed1997

Combined phentermine/fenfluramine administration enhances depletion of serotonin from central terminal fields.

Administration of phentermine (Phen) together with (+/-) fenfluramine (Fen) enhances the weight reduction that is observed with either drug alone; consequently, these anorectic agents are commonly prescribed together for weight reduction. Repeated administration of Fen is known to cause long-term depletion of axonal serotonin (5-HT) and loss of 5-HT transporters, and is therefore considered neurotoxic. We now report that combined administration of Phen/Fen (5 mg/kg/3.125 mg/kg, and 20 mg/kg/3.125 mg/kg) can enhance the neurotoxic effect of Fen (3.125 mg/kg) and Phen (5 mg/kg and 20 mg/kg) on central 5-HT systems. Rats were repeatedly treated once each hour for a total of four injections with saline, Phen (5 mg/kg and 20 mg/kg), Fen (3.125 mg/kg and 12.5 mg/kg), or combined Phen/Fen (5 mg/kg/3.125 mg/kg and 20 mg/kg/3.125 mg/kg), and sacrificed either 7 or 28 days after cessation of treatment. Combined administration of Phen/Fen (5 mg/kg/3.125 mg/kg and 20 mg/kg/3.125 mg/kg) caused significantly greater reductions of 5-HT levels in the striatum, nucleus accumbens/olfactory tubercle, hypothalamus, amygdala, frontal parietal cortex, and hippocampus than either drug alone. Combined Phen/Fen at the higher drug-dose combination (20 mg/kg/3.125 mg/kg) was observed to reduce the density of 5-HT transporters in rat striatum at both 7 and 28 days after cessation of treatment. In addition, combined administration of Phen/Fen (5 mg/kg/3.125 mg/kg and 20 mg/kg/3.125 mg/kg) caused greater weight loss than that observed with either compound alone. Collectively, the present data demonstrate that combined Phen/Fen administration enhances the neurotoxicity of Phen or Fen on 5-HT neurons.

Animals↗
PubMed1997

Evaluation of d-amphetamine effects on the binding of dopamine D-2 receptor radioligand, 18F-fallypride in nonhuman primates using positron emission tomography.

We have investigated the ability of dopamine to compete with the binding of the high affinity dopamine D2 receptor positron emission tomography (PET) radioligand, 18F-fallypride. In vitro dissociation of 18F-fallypride with dopamine in rat striatal homogenates exhibited a dissociation rate, k(off), of 1.76 x 10(-2) min(-1) while the association rate constant, k(on), was found to be 5.30 x 10(8) M(-1) min(-1). This resulted in a dissociation constant, K(D) of 33 pM for 18F-fallypride. For in vivo studies, we investigated the effects of reserpine and d-amphetamine treatment on 18F-fallypride in an attempt to study competition of endogenous dopamine with the radioligand at the receptor sites in rats and monkeys. PET experiments with 18F-fallypride in two male rhesus monkeys were carried out in a PETT VI scanner. In control experiments, rapid specific uptake of 18F-fallypride in the striata was observed (0.05-0.06% injected dose (ID)/g) while nonspecifically bound tracer cleared from other parts of the brain. Striata/cerebellum ratios for 18F-fallypride were approximately 8 at 80 min postinjection, respectively. The monkeys received various doses (0.25 to 1.50 mg/kg) of d-amphetamine (AMPH) pre- and postinjection of the radioligand. There was a decrease of specifically bound 18F-fallypride as well as evidence of an enhanced clearance of specifically bound 18F-fallypride after administering AMPH in the two monkeys. The dissociation rates, k(off), of 18F-fallypride without AMPH was <10(-4) min(-1) but after 25 min preadministration of AMPH (1 mg/kg), it was 4.1 x 10(-3) min(-1) and after 17, 45 and 90 min postadministration of AMPH (1 mg/kg) it was 3.6 x 10(-3) to 4.0 x 10(-3) min(-1). Lower doses of AMPH (0.25 mg/kg) had a reduced effect on the binding of 18F-fallypride. No effect was seen until about 30 minutes after the injection of AMPH. Studies with various doses indicated that 18F-fallypride has a maximum response at doses of 0.75-1.50 mg/kg, with an approximately 16%/hour reduction in binding. These results indicate that AMPH stimulated release of endogenous dopamine reduces the specific binding of 18F-fallypride.

Animals↗
PubMed1996

Liver biopsy findings in 501 patients infected with human immunodeficiency virus (HIV).

Patients infected with human immunodeficiency virus (HIV) are at risk for a variety of liver diseases. We undertook a retrospective study of 501 HIV-seropositive patients to assess the yield of percutaneous liver biopsy. The most common indications for liver biopsy were liver test abnormalities (89.5%), fever for 2 weeks (71.9%), and hepatomegaly (52.0%). The most common biopsy-derived diagnosis was Mycobacterium avium complex (MAC), seen in 87 (17.4%) biopsies. Mycobacterium tuberculosis was found in 13 biopsies (2.6%). In 28 biopsies (5.6%) mycobacteria was seen, but speciation of the organism was not possible. Chronic active viral hepatitis was seen in 60 biopsies (12.0%). Opportunistic hepatic infection from other organisms was found in 14 biopsies (2.8%). The most common neoplasm was lymphoma, which was seen in 12 biopsies (2.4%). MAC infection of the liver was associated with elevated alkaline phosphatase (p = 0.01). Among patients with fever for 2 weeks after an extensive negative workup including bone marrow biopsy, 58.2% had a diagnosis by liver biopsy. Overall, 64.3% of liver biopsies yielded a histopathological diagnosis, 45.7% of which were potentially treatable. We could not evaluate whether liver biopsy had a positive effect on patient outcome and survival, nor did we attempt to prove that liver biopsy resulted in a change in treatment or a change in preprocedure clinical diagnosis. Thus, questions about the efficacy of liver biopsy cannot be answered. Liver biopsy may be a helpful diagnostic tool in HIV-positive patients with fever, liver test abnormalities or hepatomegaly.

Adolescent↗
PubMed1996

Methylenedioxymethamphetamine-induced serotonin deficits are followed by partial recovery over a 52-week period. Part I: Synaptosomal uptake and tissue concentrations.

The effects of a high dose methylenedioxymethamphetamine (MDMA) regimen on the serotonin (5-HT) system were evaluated over a 52-wk period. MDMA was administered to rats (20 mg/kg) 8 times at 12-hr intervals. Tissue concentrations of dopamine (DA) and 5-HT, and synaptosomal uptake of 3H-5-HT and 3H-DA were measured at 2, 8, 16, 32 or 52 wk posttreatment. Synaptosomal uptake of 3H-5-HT (hippocampus) was decreased at 2 and 8 wk, but not at 16, 32 or 52 wk after drug. 5-HT tissue concentrations were measured in frontal cortex, frontal-parietal cortex, occipital-temporal cortex, nucleus accumbens/olfactory tubercle, striatum, amygdala, hippocampus, septum, hypothalamus, ventral tegmentum/substantia nigra. Two weeks after MDMA treatment, all regions showed decreased 5-HT tissue concentrations except septum. Recovery over the 52-wk interval was noted for all depleted regions, but the rate and degree of recovery was region dependent. Frontal-parietal cortex, occipital-temporal cortex and hippocampus showed the least recovery, with significant depletions at 52 wk posttreatment. Hypothalamus showed an increase in 5-HT tissue concentrations relative to age-matched controls at 52 wk. These results indicate that a high-dose MDMA regimen results in long-lasting depletions of serotonin. The rate and degree of recovery of serotonin tissue concentrations seen over the 52-wk test period is region specific.

Animals↗
PubMed1996

Methylenedioxymethamphetamine-induced serotonin deficits are followed by partial recovery over a 52-week period. Part II: Radioligand binding and autoradiography studies.

In our study, age-matched Holtzman Sprague-Dawley rats (275-300 g) received injections with either saline (0.9%) or 3,4-methylenedioxymethamphetamine (MDMA; 20 mg/kg free base, s.c) twice daily for 4 days and allowed to recover for 2, 8, 16, 32 and 52 wk after the final injection before death. Radioligand binding studies with 125I-RTI-55 to dopamine uptake sites in striatal homogenates showed no effect of MDMA on the density of dopamine uptake sites. In contrast, saturation binding studies with 125I-RTI-55 to 5-HT uptake sites in hippocampal and frontal-parietal homogenates showed a significant reduction in the number of uptake sites at 2 wk after MDMA treatment (34 and 25%, respectively of controls). By 16 wk, a partial recovery in the number of 5-HT uptake sites was observed in both tissues; however, only a full recovery of serotonin uptake sites was observed in hippocampus at the end of 52 wk. In more detailed studies using autoradiography with 125I-RTI-55, recovery of serotonin uptake sites varied from region to region. In particular, recovery of 5-HT uptake sites in cerebral cortex was observed to follow a rostral-caudal gradient. In addition, recovery of 5-HT uptake site in hippocampus also followed a rostral-caudal gradient. Different rates of recovery of 5-HT uptake sites were also observed for cingulate cortex, laterodorsal thalamus and ventromedial hypothalamus. No effect of MDMA was observed over lateral hypothalamus, substantia nigra and ventral tegmental area, or over serotonergic cell bodies such as dorsal raphe and median raphe. In conclusion, our study is consistent with previous studies describing the selective neurotoxicity of MDMA for serotonin neurons and presents evidence showing the rate of recovery of 5-HT uptake sites varies according to region and that recovery of 5-HT uptake sites in neocortex and hippocampus follows a rostral-caudal gradient.

Animals↗
PubMed1994

Bone mineral density in the femur and lumbar vertebrae decreases after twelve weeks of diabetes in spontaneously diabetic-prone BB/Worcester rats.

The accumulated data indicate that bone mineral density (BMD) is decreased in humans with insulin-dependent diabetes mellitus. The purpose of this study was to prospectively determine sequential lumbar and femoral BMD utilizing dual energy X-ray absorptiometry in rats that spontaneously become diabetic to determine if weight and blood glucose control would prevent the diabetes-related bone mass changes. BMD of the lumbar spine and femur was measured prior to the onset of diabetes and at 3-week intervals after the diagnosis of diabetes for 12 weeks in 14 diabetes-prone BB/Wor rats (DP) and eight diabetes-resistant BB/Wor control rats (DR). At 12 weeks, the lumbar (0.238 +/- 0.013 vs 0.262 +/- 0.007 g/cm2, P < 0.001) and femoral (0.313 +/- 0.013 vs 0.343 +/- 0.013 g/cm2, P < 0.001) BMD were significantly lower in the DP rats despite significantly greater body weights (387 +/- 26 vs 329 +/- 46 g, P < 0.001) and plasma glucose levels of only 178 mg/dl. There was no difference in plasma values of calcium, phosphorus, osteocalcin, or tartrate-resistant acid phosphatase between groups or differences in osteoblast numbers in histologic sections. There was a significant (P < 0.001) decrease in plasma creatinine in the diabetic animals. The results indicate that in this animal model of type I diabetes, spine and femoral BMD do not increase comparable to control despite weight and blood glucose control. This would suggest that the diabetic condition itself affects bone mass in the absence of weight loss and poor blood glucose control.

Absorptiometry, Photon↗
PubMed1994

Responsiveness of gene expression markers of osteoblastic and osteoclastic activity to calcitonin in the appendicular and axial skeleton of the rat in vivo.

We have previously shown that calcitonin (CT), an inhibitor of bone resorption, increases vertebral, but not femoral bone density in the rat. To address the physiologic responses associated with these effects on bone mineral density (BMD), we assessed mRNA transcripts reflecting activities of osteoblasts (type I collagen, osteocalcin, osteopontin, and alkaline phosphatase), osteoclasts [tartrate-resistant acid phosphatase (TRAP)], and cell proliferation (histone H4) in the spine and femur of these rats. CT increased spine BMD while increasing type I collagen and decreasing TRAP and histone mRNAs. In the femur, where CT had no effect on BMD, it decreased type I collagen and histone H4 mRNA but did not affect TRAP. CT had no effect on the gene expression of osteocalcin, osteopontin, or alkaline phosphatase at either site. The results indicate that selective alterations in gene expression, as reflected by steady state mRNA levels, are consistent with the changes observed by BMD measurement, and can more clearly define the specific contribution from osteoblast and osteoclast activity. This study demonstrates a heterogeneity in response of the axial and appendicular skeleton to CT, reflected by alterations in gene expression that provide a basis for understanding the observed BMD responses to various pharmacologic interventions.

Acid Phosphatase↗
PubMed1994

A study of the impact of leg ulcers on quality of life: financial, social, and psychologic implications.

BACKGROUND: Leg ulcers affect probably 2.5 million persons in the United States, and their prevalence is likely to rise as the population ages. They cause considerable disability, and the cost of treating these chronic wounds is enormous. OBJECTIVE: The purpose of this study was to assess the financial, social, and psychologic implications of leg ulcers. METHODS: Data were collected by standardized personal interviews with 73 patients with chronic leg ulcers. The interview covered several domains that were selected to determine the impact of a leg ulcer on overall quality of life. RESULTS: A significant number of patients had moderate to severe symptoms, principally pain, related to the leg ulcer. Eighty-one percent believed that their mobility was adversely affected by the ulcer; the dominant predictor of impaired mobility was swelling of the leg (p < 0.001). For younger, working patients, leg ulceration was correlated with time lost from work (p < 0.001), job loss (p < 0.01), and adverse effects on finances (p < 0.02). Fifty-eight percent of patients found caring for the ulcer burdensome. There was a strong correlation between time spent on ulcer care and feelings of anger and resentment. Sixty-eight percent of patients reported that the ulcer had a negative emotional impact on their lives, including feelings of fear, social isolation, anger, depression, and negative self-image. CONCLUSION: Leg ulcers pose a substantial threat to a variety of dimensions of a patient's quality of life.

Adult↗
PubMed1993

Many peptides that are present in the external zone of the median eminence are not secreted into the hypophysial portal blood of sheep.

Apart from the well recognized factors that are produced by the hypothalamus and secreted into hypophysial portal blood to regulate pituitary function, there is a range of neuropeptides that are present in the median eminence and could be secreted to serve a modulatory function. In this study we have collected hypophysial portal blood and jugular venous blood from sheep in an attempt to identify which of these putative modulatory peptides might be secreted from the median eminence. We have measured neuropeptide Y (NPY), substance P (SP), galanin (GAL), neurokinin A (NKA), peptide histidine isoleucine (PHI), vasoactive intestinal peptide (VIP), neurotensin (NT) and cholecystokinin (CCK). We also examined the sheep median eminence using immunohistochemistry for NPY, SP and GAL and determined degradation profiles of NPY, SP, GAL and NKA in portal and jugular plasma. In no instance did we find that levels of the above peptides were consistently higher in portal blood than in peripheral blood. In some cases levels of peptide were lower in portal plasma e.g. for NPY (6/10 sheep). In one experimental series SP levels in portal plasma were significantly (p < 0.05) lower than levels in jugular plasma but this was not found in another experimental series. Galanin levels were significantly (p < 0.01) lower in portal plasma compared to levels in jugular plasma. We conducted in vitro studies to determine whether or not the above peptides are selectively degraded in portal blood but were unable to show any differences between the rates of degradation in portal and jugular plasma. Immunohistochemistry revealed projections into the external zone of the median eminence for NPY, GAL and SP. This study shows that none of the above peptides are secreted into the hypophysial portal blood of sheep. For some peptides e.g. GAL, enzymes from the endothelial cells of the portal vessels may enhance degradation. Projections into the external zone of the median eminence of neuronal systems containing these peptides may serve to modulate the secretion of the well recognized release and inhibiting factors by acting on the neurosecretory terminals.

Animals↗
PubMed1993

High stimulatory activity of dendritic cells from diabetes-prone BioBreeding/Worcester rats exposed to macrophage-derived factors.

Dendritic cells (DC) present antigen and initiate T cell-mediated immune responses. To investigate the possible association of autoimmunity with DC function, we compared the accessory activity of splenic DC from Wistar/Furth (WF) and diabetes-prone (DP) BioBreeding (BB) rats. The latter develop autoimmune diabetes and thyroiditis. DC function was quantified in vitro by measuring T cell proliferation in mitogen-stimulated and mixed lymphocyte reactions. When purified without macrophage coculture, WF and DP DC displayed similar levels of accessory activity. In contrast, when purified by a method involving coculture with macrophages, DC from DP rats consistently displayed greater accessory activity. This finding could not be explained by morphological or phenotypic differences between DP and WF DC. In accessory activity assays performed after reciprocal DC cocultures with DP and WF macrophages, DP DC exhibited higher accessory activity irrespective of macrophage donor strain. We also compared the accessory activity of WF and DP DC cultured in the presence of conditioned medium and a mixture of IL-1 and GM-CSF. In all assays, DP DC exhibited higher accessory activity. In studies of (WF x DP) F1 hybrids, the high accessory activity of DP DC was observed to be heritable, and studies of WF and DP radiation chimeras indicated that the effect was an intrinsic property of the DP hematopoietic system. We conclude: (a) splenic DC from DP and WF rats possess similar basal levels of accessory potency; (b) after interaction with macrophages, DC of DP origin are capable of greater stimulatory activity than are WF DC; and (c) the mechanism responsible for this phenomenon involves differential responsiveness of DP and WF DC to macrophage-derived factors such as IL-1 and GM-CSF.

Animals↗
PubMed1992

Microheterogeneity of dopamine transporters in rat striatum and nucleus accumbens.

Previously we have shown that the [125I]DEEP-labeled dopamine transporter from the rat nucleus accumbens has a higher apparent molecular weight than that from striatum. The present study confirms and extends these observations. Experiments with nucleus accumbens showed [125I]-DEEP to specifically bind to a protein with an apparent molecular weight of 76 kDa and with the pharmacological properties of the dopamine transporter. In exoglycosidase studies, treatment with neuraminidase, but not alpha-mannosidase, reduced the apparent molecular weight of the dopamine transporter from both the striatum and nucleus accumbens; however, a difference in the apparent molecular weight was still observed. N-Glycanase treatment, on the other hand, did reduce the apparent molecular weight of the dopamine transporters from the two regions to a similar value, approximately 56 kDa. In radioligand binding studies examining the effect of partial deglycosylation on striatal dopamine transporters, neuraminidase did not affect specific [3H]WIN 35,428 binding at 4 and 40 nM concentrations. In conclusion, the present study demonstrates that the difference in the apparent molecular weight of the dopamine transporter from these two regions is due to a difference in glycosylation and that the dopamine transporter from both regions contains similar amounts of sialic acid in their carbohydrate structure. Furthermore, the present data also indicate that the polypeptide portion of the dopamine transporter from both regions could be the same gene product.

Animals↗
PubMed1992

Probes for the cocaine receptor. Potentially irreversible ligands for the dopamine transporter.

Several potentially irreversible ligands (i.e., wash-resistant binding inhibitors) for the cocaine receptor site on the dopamine transporter, derived from (-)-cocaine or 3 beta-phenyltropan-2 beta-carboxylic acid methyl ester (WIN 35,065-2), were prepared and shown to produce wash-resistant inhibition of [3H]-3 beta-(p-fluorophenyl)tropan-2 beta-carboxylic acid methyl ester ([3H]WIN 35,428) binding. All the compounds prepared had the same absolute configuration as cocaine; they include analogues possessing chemically reactive groups such as the isothiocyanato and bromoacetamido as well as photoactive azido groups. The potentially irreversible ligands, as well as all the intermediates prepared in this study, were evaluated for their ability to inhibit the binding of [3H]WIN 35,428 in coincubation experiments. Of the potentially irreversible ligands, 3 beta-(p-chlorophenyl)tropan-2 beta-carboxylic acid 2-[p-(bromoacetamido)phenyl]ethyl ester (6c) had the highest apparent potency. The potentially irreversible ligands were also preincubated, and inhibition of [3H]WIN 35,428 binding was determined both before and after washing the ligand-exposed tissues. The most effective ligands in this regard were 3 beta-(3-iodo-4-azidophenyl)tropan-2 beta-carboxylic acid methyl ester (5) and 3 beta-(p-chlorophenyl)tropan-2 beta-carboxylic acid 2-(3-iodo-4-azidophenyl)ethyl ester (6d). The structure-activity relationships of these data are discussed.

Animals↗
PubMed1992

A cocaine analog and a GBR analog label the same protein in rat striatal membranes.

Because some evidence suggests that cocaine and GBR12935 bind to different sites, we utilized photoaffinity probes from both classes of compounds to see if they label the same protein. [125I]RTI-82 a cocaine analog, and [125I]DEEP, a GBR analog, labeled protein(s) showing the same molecular weight, a similar pharmacological profile and a similar sensitivity to neuraminidase.

Animals↗
PubMed1992

Relationship between immune response to melanoma vaccine immunization and clinical outcome in stage II malignant melanoma.

The authors investigated whether there was a relationship between the induction of a delayed-type hypersensitivity (DTH) response to melanoma vaccine immunization and disease recurrence. They studied prospectively 94 evaluable patients with surgically resected Stage II malignant melanoma who were immunized to a partially purified, polyvalent, melanoma antigen vaccine. The DTH response to skin tests to the vaccine was measured before treatment and at the fourth vaccine immunization. Vaccine treatment induced a strong DTH response in 29 (31%) patients, an intermediate response in 24 (25%), and no response in 41 (44%). The median disease-free survival (DFS) of patients with a strong, intermediate, and no DTH response to vaccine immunization was more than 72 months, 24 months, and 15 months, respectively. The relationship between an increase in the DTH response and a prolonged DFS was statistically significant (P = 0.02); clinically meaningful (the median DFS of patients with a strong DTH response was 4.7 years longer than that of nonresponders); and, by multivariate analysis, independent of disease severity or overall immune competence. These findings suggest, but do not prove, that vaccine treatment can slow the progression of melanoma in some patients.

Adult↗
PubMed1992

Estrogen receptor immunohistochemistry in carcinoma in situ of the breast.

Although estrogen receptor (ER) content and its clinical significance have been extensively evaluated in invasive breast cancer, ER expression in carcinoma in situ (CIS) of the breast and its correlates are less well understood. Thus, using an indirect immunoperoxidase technique and paraffin-embedded tissue, the authors studied ER expression in 100 breast tumors containing CIS with or without invasive carcinoma. The percentages of positive and of strongly positive nuclei were compared among histologic categories of CIS and between CIS and invasive carcinoma. The relationships between histologic features of CIS (cell size, nuclear pleomorphism, necrosis, extent of CIS) the patient's age, and the ER status of CIS also were evaluated. ER expression in pure CIS was compared with that of CIS with adjacent invasive carcinoma. Significant differences were observed between comedo CIS, which was frequently ER negative, and non-comedo and lobular CIS, which usually were positive. A predominance of large cells, independently from other features, was the best morphologic predictor of ER negative status in CIS. ER in CIS correlated with ER in invasive carcinoma in 98% of cases (r2 = 0.677). CIS without invasive carcinoma was more frequently ER weak or negative than CIS associated with invasive carcinoma. There was no difference in the overall percentage of nuclear staining in CIS of women of premenopausal versus postmenopausal age; however, a higher proportion of strongly positive cells occurred in the postmenopausal group. The authors conclude that the ER expression in CIS correlates with pathologic features of differentiation and is similar to that of invasive carcinoma.

Adult↗
PubMed1992

Suspected low-grade glioma: is deferring treatment safe?

Deferring therapeutic intervention may worsen outcome in patients with low-grade glioma. To address this issue, we searched our records and located 26 patients who presented with a transient event (most often seizures), who had radiographic evidence strongly suggestive of a low-grade primary supratentorial neoplasm, and for whom all therapy (except anticonvulsants) was withheld until deemed necessary (WAIT Group). For comparison, 20 patients who presented similarly, but for whom immediate intervention was elected, served as a comparison group (NOWAIT Group). Fifteen patients in the WAIT Group required eventual surgery or radiation therapy at intervals ranging from 4 to 123 months (median, 29 months) between radiographic diagnosis and therapeutic intervention; reasons for such intervention included increasing tumor size, uncontrollable seizures, or malignant transformation of tumor. At surgery, there was an increased number of anaplastic tumors noted in the patients in the WAIT Group (p less than 0.02); nevertheless, if the rate of malignant transformation was examined from time of diagnosis, no differences were noted between the patients in the two groups. Similarly, no difference in survival or quality of life could be demonstrated from time of radiographic diagnosis. Therefore, we could not demonstrate that deferring therapy worsens outcome for these patients.

Brain Neoplasms↗
PubMed1992

The relationship between ultrasound and densitometric measurements of bone mass at the calcaneus in women.

Broadband ultrasound attenuation (BUA) of the calcaneus predicts axial density in women and is decreased in women who sustain hip fractures. To determine the relationship between ultrasonic and densitometric assessments of bone mass at the same site, BUA and velocity of sound (VOS) were correlated with bone density as measured by dual energy x-ray absorptiometry (DXA) at the calcaneus in 64 Caucasian women aged 35-83 years. BUA, VOS, and bone density in these women decreased annually as a function of age by 1.0%, 0.3%, and 0.9%, respectively. Holding age, years since menopause, height and weight constant, BUA correlated with VOS (r = 0.74, P < 0.001), and calcaneal density correlated with BUA (r = 0.73, P < 0.001) and with VOS (r = 0.66, P < 0.01). The results indicate that both BUA and VOS measurements reflect density at the calcaneus, but suggest that they measure properties of bone other than density and different from each other. The assessment of these additional properties may be useful in the prediction of fracture risk.

Absorptiometry, Photon↗