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Biomedical subjects

B L Riggs

Publications and source records attributed to B L Riggs.

At least 55 records · Page 3Linked to original sources
PubMed1999

Raloxifene hydrochloride, a selective estrogen receptor modulator: safety assessment of effects on cognitive function and mood in postmenopausal women.

Raloxifene hydrochloride (HCl) is a selective estrogen receptor modulator with estrogen agonist effects on bone and lipid metabolism and estrogen antagonist effects on reproductive tissues. Animal studies suggest that raloxifene may affect brain function as well, although the effects of raloxifene on the human brain remain to be established. This paper presents an early safety assessment of raloxifene effects on cognition and mood in postmenopausal women participating in a randomized, double-blind osteoporosis treatment trial. Psychometric test batteries were administered to postmenopausal women at baseline and 1, 6, and 12 months after initiating treatment with raloxifene (60 and 120 mg/day). The Memory Assessment Clinics (MAC) battery and Walter Reed Performance Assessment Battery (PAB) were used to assess multiple and independent aspects of cognitive function, while mood was assessed with the Geriatric Depression Scale (GDS). After 12 months of treatment, there were no significant differences between the raloxifene groups and placebo on performance in either the MAC battery or the PAB. The only significant difference observed was a slight increase in performance favoring the raloxifene 120 mg/day group in an assessment of verbal memory on the MAC battery after 1 month of treatment. Scores on the GDS and the self-reported incidence of mood-related events were not different between treatment groups at any of the assessment periods. These data do not suggest that raloxifene impairs cognition or affects mood in postmenopausal women treated for 1 year. Studies to further assess the safety and potential efficacy of raloxifene with respect to cognitive function are ongoing.

Adult↗
PubMed1999

Secondary osteoporosis and the risk of vertebral deformities in women.

Among an age-stratified sample of 942 Rochester, MN women, the overall prevalence of any vertebral deformity, as assessed by radiographic morphometry, was 21.3 per 100. The prevalence increased with age and, after adjusting for age, vertebral deformities were independently associated with height, weight, a history of distal forearm or hip fractures, and anticoagulant use. Altogether, 73% of the women with a vertebral deformity and 66% of controls had one or more of the conditions that have been linked with secondary osteoporosis, which in aggregate were associated with an age-adjusted 1.2-fold (95% CI 0.8-1.7) increase in risk that was not statistically significant. The prevalence of severe vertebral deformities was 11.7 per 100 women and the prevalence of very severe deformities was 5.7 per 100. There was a stronger relationship of age and most other risk factors with severe vertebral deformities than with isolated mild deformities, suggesting that a subset of mild deformities may not represent actual vertebral fractures. The metabolic disorders linked with secondary osteoporosis were associated with little increase in the risk of severe vertebral deformities, taken together, or of mild deformities. However, in aggregate these conditions were associated with a 2.3-fold increase (95% 1.1-4.8) in very severe vertebral deformities, which points to a role for rapid cancellous bone loss among women with the worst spinal osteoporosis.

Case-Control Studies↗
PubMed1999

Interleukin-1beta and tumor necrosis factor-alpha, but not interleukin-6, stimulate osteoprotegerin ligand gene expression in human osteoblastic cells.

Recent studies have identified osteoprotegerin ligand (OPG-L) as the essential factor required for osteoclastogenesis, and that the effects are prevented by its soluble receptor, osteoprotegerin (OPG). However, there are limited data at present on the regulation of OPG-L expression in human osteoblastic cells by other cytokines. Because interleukin (IL)-1beta, tumor necrosis factor (TNF)-alpha, and IL-6 all increase osteoclastogenesis, we assessed whether OPG-L mRNA steady-state levels were regulated by these cytokines in human osteoblastic cells. By northern analysis, IL-1beta (5 nmol/L) and TNF-alpha (9 nmol/L) increased OPG-L mRNA steady-state levels by up to two- to three-fold in normal marrow stromal cells (MS), an immortalized marrow stromal cell line (hMS), and the osteosarcoma cell line, MG-63, whereas IL-6 (2 nmol/L, with or without its soluble receptor) had no effect on OPG-L mRNA levels in any of these cells. IL-1beta and TNF-alpha increased OPG-L mRNA steady-state levels in the normal MS cells and the hMS cell line in a time- and dose-dependent fashion by up to 4.1-fold and up to 2.6-fold, respectively. Our data are thus consistent with the hypothesis that the proinflammatory and bone-resorbing cytokines, IL-1beta and TNF-alpha, but not IL-6, may stimulate osteoclastogenesis by inducing the expression of OPG-L.

Blotting, Northern↗
PubMed1999

Osteoporosis: gender differences and similarities.

Although osteoporosis has traditionally been considered a disease of women, men also incur substantial bone loss with aging, and elderly men have age-specific hip fracture incidence rates and vertebral fracture prevalence rates that are at least half those in women. Early postmenopausal bone loss (which results in the syndrome of type I osteoporosis) is due to the direct skeletal consequences of estrogen deficiency, manifested by an increase in bone resorption without an adequate increase in bone formation. Recent evidence indicates that even late postmenopausal bone loss (type II or 'smile' osteoporosis) in women may be due to estrogen deficiency. In particular, the late consequences of estrogen deficiency in elderly women result in abnormalities in calcium homeostasis and increases in parathyroid hormone secretion, leading to increased bone resorption and bone loss. The etiology of bone loss in aging men has remained relatively unclear. Recent evidence from a male deficient in estrogen receptor-alpha and in two males with aromatase deficiency indicate that estrogen may play a significant role in bone metabolism in men. Moreover, several large epidemiologic studies have found that bone mineral density correlates better with serum estrogen than testosterone in aging men. Thus estrogen deficiency may lead to bone loss in men.

Adult↗
PubMed1999

Stimulation of osteoprotegerin ligand and inhibition of osteoprotegerin production by glucocorticoids in human osteoblastic lineage cells: potential paracrine mechanisms of glucocorticoid-induced osteoporosis.

Osteoporosis is a serious complication of systemic glucocorticoid use. However, while glucocorticoids increase bone resorption in vitro and in vivo, the mechanism(s) of this effect are at present unclear. Recent studies have identified the osteoprotegerin (OPG) ligand (OPG-L) as the final effector of osteoclastogenesis, an action that is opposed by the soluble neutralizing receptor, OPG. Thus, we assessed glucocorticoid regulation of OPG and OPG-L in various human osteoblastic lineage cells using Northern analysis, RT-PCR, and ELISA. Dexamethasone inhibited constitutive OPG messenger RNA (mRNA) steady-state levels by 70-90% in primary (MS) and immortalized stromal cells (hMS), primary trabecular osteoblasts (hOB), immortalized fetal osteoblasts (hFOB), and osteosarcoma cells (MG-63). In hFOB cells, dexamethasone inhibited constitutive OPG mRNA steady-state levels in a dose- and time-dependent fashion by 90%, and also suppressed cytokine-stimulated OPG mRNA steady-state levels. Dexamethasone-induced inhibition of OPG mRNA levels was not affected by the protein synthesis inhibitor, cycloheximide, and was shown to be due to inhibition of OPG gene transcription using a nuclear run-on assay. Moreover, dexamethasone also dose dependently (10(-10) M-10(-7) M) inhibited constitutive OPG protein concentrations in the conditioned medium of hFOB cells from 2.59 +/- 0.02 ng/ml (control) to 0.30 +/- 0.01 ng/ml (88% inhibition; P < 0.001 by ANOVA). Concurrently, dexamethasone stimulated OPG-L mRNA steady-state levels in MS and hFOB cells by 2- and 4-fold, respectively. Treatment of murine marrow cultures with conditioned medium harvested from dexamethasone-treated MG-63 cells increased tartrate-resistant acid phosphatase (TRAP) activity by 54% (P < 0.005) compared with medium harvested from control-treated cells (in the presence of OPG-L and macrophage colony-stimulating factor). Moreover, dexamethasone (10(-8) M) promoted osteoclast formation in vitro, as assessed by a 2.5-fold increase of TRAP activity in cell lysates (P < 0.001) and the appearance of TRAP-positive multinucleated cells. Our data are thus consistent with the hypothesis that glucocorticoids promote osteoclastogenesis by inhibiting OPG and concurrently stimulating OPG-L production by osteoblastic lineage cells, thereby enhancing bone resorption.

Carrier Proteins↗
PubMed1999

Response of bipotential human marrow stromal cells to insulin-like growth factors: effect on binding protein production, proliferation, and commitment to osteoblasts and adipocytes.

Insulin-like growth factors (IGFs) are important regulators of the activity of mature osteoblasts, but their effects on osteoprogenitor cells in human bone marrow stroma are unclear. In this study, we assessed the effects of IGFs on a conditionally immortalized human marrow stromal cell line, hMS(3-4), which has the ability to differentiate to either mature osteoblasts or adipocytes. hMS(3-4) cells expressed functional receptors for IGFs as well as specific IGF-binding proteins (IGFBP-3, -4, -5, and -6). IGF treatment of hMS(3-4) cells did not alter IGFBP expression, but resulted in distinct posttranslational modifications of secreted IGFBP-3 and IGFBP-4 proteins. IGF-I, IGF-II, and their receptor-activating analogs significantly increased by 2-fold the proliferation rate of the hMS(3-4) cells, but had a more complex effect on hMS(3-4) cell differentiation. Treatment with IGFs did not affect gene expression of Cbfa1 or peroxisome proliferator-activated receptor gamma2 (transcription factors involved in commitment to osteoblast and adipocyte pathways, respectively), alkaline phosphatase, type I collagen, and osteocalcin (markers of the osteoblast lineage), or lipoprotein lipase and adipsin (markers of the adipocyte lineage) and did not change alkaline phosphatase activity or type I collagen and osteocalcin protein relative to total protein production. In contrast, IGFs significantly increased type I collagen expression in differentiated hMS(3-4) cells as well as mature osteoblasts and promoted lipid accumulation in differentiated adipocytes. In summary, hMS(3-4) cells express essential components of the IGF system and respond to IGF treatment with increased proliferation. There was no evidence for IGFs directly modulating the commitment of hMS(3-4) cells to either osteoblast or adipocyte pathways, and their effects on differentiation within these lineages were dependent on the stage of cell maturation.

Adipocytes↗
PubMed1999

Leptin acts on human marrow stromal cells to enhance differentiation to osteoblasts and to inhibit differentiation to adipocytes.

Both bone mass and serum leptin levels are increased in obesity. Because osteoblasts and adipocytes arise from a common precursor in bone marrow, we assessed the effects of human recombinant leptin on a conditionally immortalized human marrow stromal cell line, hMS2-12, with the potential to differentiate to either the osteoblast or adipocyte phenotypes. By RT-PCR and Western immunoblot analysis, the hMS2-12 cells expressed messenger RNA (mRNA) and protein for the leptin receptor. Leptin did not affect hMS2-12 cell proliferation, but resulted in dose- and time-dependent increases in mRNA and protein levels of alkaline phosphatase, type I collagen, and osteocalcin, and in a 59% increase in mineralized matrix. Leptin increased mRNA levels of lipoprotein lipase at 3 days, but decreased mRNA levels of adipsin and leptin at 9 days and decreased lipid droplet formation by 50%. Leptin did not affect the expression of Cbfa1 or peroxisome proliferator-activated receptor-gamma2, transcription factors involved in commitment to the osteoblast and adipocyte pathways, respectively. Thus, leptin acts on human marrow stromal cells to enhance osteoblast differentiation and to inhibit adipocyte differentiation. Our data support the hypothesis that leptin is a previously unrecognized, physiological regulator of these two differentiation pathways, acting primarily on maturation of stromal cells into both lineages.

Adipocytes↗
PubMed1999

Estrogen stimulates gene expression and protein production of osteoprotegerin in human osteoblastic cells.

The identity of the paracrine mediator(s) of the antiresorptive action of estrogen on bone cells is controversial. Osteoprotegerin (OPG) was recently identified as a soluble member of the tumor necrosis factor (TNF) receptor (TNF-R) superfamily that is secreted by osteoblast lineage cells and acts by binding to and neutralizing its cognate ligand, OPG-L, a required factor for osteoclastogenesis. OPG prevents bone loss when administered to ovariectomized rats, induces osteoporosis when ablated in knock-out mice, and induces osteopetrosis when overexpressed in transgenic mice. In conditionally immortalized, human osteoblastic hFOB/ER-3 and hFOB/ER-9 cell lines containing physiological concentrations of approximately 800 and approximately 8,000 functional estrogen receptors (ER)/nucleus, respectively, we found that 17beta-estradiol dose- and time-dependently increased OPG mRNA and protein levels to maximal levels of 370% and 320%, respectively (P < 0.001); co-treatment with the "pure" antiestrogen ICI 182,780 abrogated these effects completely. 17beta-Estradiol also dose-dependently increased OPG mRNA and protein levels in normal human osteoblasts with approximately 400 ER/nucleus by 60% and 73%, respectively. Thus, estrogen enhancement of OPG secretion by osteoblastic cells may play a major role in the antiresorptive action of estrogen on bone.

Cells, Cultured↗
PubMed1999

Differentiation of human marrow stromal precursor cells: bone morphogenetic protein-2 increases OSF2/CBFA1, enhances osteoblast commitment, and inhibits late adipocyte maturation.

Because regulation of the differentiation to osteoblasts and adipocytes from a common progenitor in bone marrow stroma is poorly understood, we assessed effects of bone morphogenetic protein-2 (BMP-2) on a conditionally immortalized human marrow stromal cell line, hMS(2-6), which is capable of differentiation to either lineage. BMP-2 did not affect hMS(2-6) cell proliferation but enhanced osteoblast differentiation as assessed by a 1.8-fold increase in expression of OSF2/CBFA1 (a gene involved in commitment to the osteoblast pathway), by increased mRNA expression and protein secretion for alkaline phosphatase (ALP), type I procollagen and osteocalcin (OC) (except for OC protein), and by increased mineralized nodule formation. Transient transfection with Osf2/Cbfa1 antisense oligonucleotide substantially reduced BMP-2-stimulated expression of ALP mRNA and protein. The effects of BMP-2 on adipocyte differentiation varied: expression of peroxisome proliferator-activated receptor gamma2 (a gene involved in commitment to the adipocyte pathway) was unchanged, mRNA expression of the early differentiation marker, lipoprotein lipase, was increased, and mRNA and protein levels of the late differentiation marker, leptin, and the formation of cytoplasmic lipid droplets were decreased. Thus, by enhancing osteoblast commitment and by inhibiting late adipocyte maturation, BMP-2 acts to shunt uncommitted marrow stromal precursor cells from the adipocyte to the osteoblast differentiation pathway.

Adipocytes↗
PubMed1999

Practical clinical application of biochemical markers of bone turnover: Consensus of an expert panel.

Biochemical markers of bone turnover have emerged as powerful tools to aid in managing osteoporosis. The newer bone markers have been intensively studied for more than a decade. As a result, we can now confidently report their clinical utility in assessing risk of rapid bone loss and fracture, and monitoring therapy in postmenopausal women with or at risk of osteoporosis. In this review, we will provide a comprehensive foundation for this utility. While there are still questions remaining to be answered, bone marker technology has matured to play an essential role in patient management. We will describe, in practical terms, how bone markers can be appropriately incorporated into clinical practice today.

Aged↗
PubMed1999

Immunoradiometric assay for intact human osteocalcin(1-49) without cross-reactivity to breakdown products.

BACKGROUND: Osteocalcin (Oc), a serum marker of bone turnover, circulates in several forms. We developed an assay for intact human Oc and investigated its clinical features. METHODS: We generated goat antibodies and N- and C-terminal Oc. The former was used on solid phase (polystyrene beads), and the latter was used as the tracer in an IRMA. RESULTS: The assay was linear with no cross-reactivity to Oc(1-43), total imprecision (CV) of <10%, and recovery of 100% +/- 10%. Assay values for intact Oc in EDTA plasma samples were unchanged at 18-25 degrees C for 6 h. Values for intact Oc in serum, EDTA plasma, and heparin plasma samples did not change after storage on ice for 8 h. Serum samples from patients with various conditions were stored at -70 or -135 degrees C for up to 5 years and yielded z-scores comparable to an Oc(1-43) IRMA for all conditions except for renal failure. In renal failure, the Oc(1-43) assay values were increased, whereas the intact assay values were in the reference interval. CONCLUSION: Decreases in Oc assay values are inhibited by calcium chelation, and slowed by reduced temperatures. The described assay for intact Oc allows improved specificity for bone compared with an assay for Oc(1-43).

Adolescent↗
PubMed1998

Osteoprotegerin production by human osteoblast lineage cells is stimulated by vitamin D, bone morphogenetic protein-2, and cytokines.

Osteoprotegerin (OPG), a newly discovered member of the tumor necrosis factor receptor family, is a potent inhibitor of osteoclastogenesis. The overexpression of OPG in transgenic mice leads to osteopetrosis, whereas targeted ablation of OPG in knock-out mice leads to severe osteoporosis. However, the production and regulation of OPG in normal human bone has not been studied. Thus, we assessed OPG mRNA expression and protein secretion in human osteoblastic lineage cells. 1,25-Dihydroxyvitamin D3 (10(-7) M) increased OPG mRNA levels by 90 and 50% in a fetal osteoblastic cell line (hFOB) and normal trabecular osteoblastic cells (hOB) cells, respectively, but did not affect OPG mRNA levels in a marrow stromal preosteoblastic (hMS) cell line. Interleukin (IL)-1beta (5 x 10(-9) M), tumor necrosis factor (TNF)-alpha (9 x 10(-9) M), and bone morphogenetic protein (BMP)-2 (100 ng/ml) also increased OPG mRNA levels in hFOB cells by 4-, 6-, and 4-fold, respectively. Treatment with 1,25-dihydroxyvitamin D3, IL-1beta, TNF-alpha, and BMP-2 increased OPG protein production by hFOB cells by 60, 390, 300, and 80%, respectively (P < 0.001). Because it is expressed in various types of human osteoblastic cells, and is stimulated by vitamin D, BMP-2 and cytokines, OPG may be an important paracrine modulator of bone remodeling.

Animals↗
PubMed1998

Capillary electrophoresis of insulin-like growth factors: enhanced ultraviolet detection using dynamically coated capillaries and on-line solid-phase extraction.

Insulin-like growth factor-I and -II (IGF-I and IGF-II) are difficult to separate and measure as a result of their homology, both structurally and immunologically. A number of binding proteins (BPs) which interact with the IGFs with high affinity complicate the ability to measure the IGFs accurately and reproducibly. Current methodology for measuring IGF is immuno-based and involves dissociation from the IGFs and removal of the binding proteins through sample acidification and removal by solid-phase adsorption. However, the net result is an assay that is time-consuming and, at best, semiquantitative. In an attempt to improve the reproducibility and accuracy of IGF-I and -II measurement, electrophoretic systems employing dynamically coated and bare silica capillaries were evaluated. Separations in bare silica capillaries in the presence or absence of the cationic additive, decamethonium bromide were ineffective for resolving IGF-I and IGF-II. However, when the capillary was coated dynamically with polybrene, IGF-I and -II could be resolved in a BSA sample matrix using a low pH buffer. Despite the fact that the IGFs could be resolved in the presence of an IGF-I analog used as an internal standard, polybrene recoating was required after as few as 12 runs and poor coating-to-coating reproducibility was observed. Use of polydiallyldimethylammonium chloride (PDMAC) as a dynamic cationic coating and a low pH buffer containing 0.5% PDMAC was found to be much more effective, providing reproducible separation of IGF-I and -II. It was found that PDMAC need not be included in the separation buffer to obtain reproducible analyses regarding IGF separation. Subsequently, functionality remained intact for as many as 35-40 consecutive analyses before recoating was required. Without the need for PDMAC in the buffer, on-line solid-phase extraction-capillary electrophoresis could be accomplished for detection of IGF-I and -II at concentrations as low 195 ng/ml.

Buffers↗
PubMed1998

Tissue, cell type, and breast cancer stage-specific expression of a TGF-beta inducible early transcription factor gene.

This laboratory has previously identified a novel TGF-beta inducible early gene (TIEG) in human osteoblasts [Subramaniam et al. (1995): Nucleic Acids Res 23:4907-4912]. Using TIEG specific polyclonal antibody and immunoprecipitation methods in normal human fetal osteoblast cells (hFOB cells), we have now demonstrated that TIEG encodes a 72-kDa protein whose levels are transiently increased at as early as 2 h of TGF-beta treatment. Polarized confocal microscopic analysis of hFOB cells shows a nuclear localized TIEG protein in untreated cells under the conditions described under Methods. Interestingly, the levels of TIEG protein in the nuclei increase when the cells are treated with TGF-beta 1 for 2 h. In contrast, similar analyses of untreated human keratinocytes show a cytoplasmic localized TIEG protein that appears to be translocated to the nucleus after H2O2 treatment. Additional immunohistochemical studies have demonstrated that TIEG protein is expressed in epithelial cells of the placenta, breast, and pancreas, as well as in osteoblast cells of bone and selected other cells of the bone marrow and cerebellum with some cells showing a cytoplasmic localization and others a nuclear localization. All cells of the kidney display negative staining for this protein. Interestingly, a stage specific expression of TIEG protein is found in a dozen breast cancer biopsies, using immunohistochemistry. The cells in normal breast epithelium displays a high expression of TIEG protein, those in the in situ carcinoma display less than one-half of the levels, and those in the invasive carcinoma show a complete absence of the TIEG protein. TIEG has been localized to chromosome 8q22.2 locus, the same locus as the genes involved in osteopetrosis and acute myeloid leukemia and close to the c-myc gene locus and a locus of high polymorphism in cancer biopsies. The correlation between the levels of TIEG protein and the stage of breast cancer, its prime location in human chromosome 8q22.2, and past studies with pancreatic carcinoma, suggests that TIEG may play a role in tumor suppressor gene activities, apoptosis, or some other regulatory function of cell cycle regulation.

Breast Neoplasms↗
PubMed1998

Bone morphogenetic protein-6 production in human osteoblastic cell lines. Selective regulation by estrogen.

Bone morphogenetic proteins (BMPs) induce differentiation of osteoblast and chondroblast lineage cells from uncommitted mesenchymal precursors. Because estrogen has potent osteochondrogenic actions, we investigated its effect on BMP production in two estrogen-responsive, human immortalized cell lines (hFOB/ER3 and hFOB/ER9) that display the mature osteoblast phenotype. These cell lines were produced by stable transfection of the estrogen receptor (ER) gene into immortalized fetal osteoblasts at low ( approximately 800 ER/ nucleus) and at high ( approximately 3, 900 ER/nucleus) levels, respectively. As assessed by reverse transcriptase PCR, treatment with 17beta-estradiol (10(-)10 - 10(-)7 M) increased steady-state levels of BMP-6 mRNA dose dependently by twofold in the hFOB/ER3 cells and by over threefold in the hFOB/ER9 cells. Messenger RNA levels for transforming growth factors-beta1 and -beta2 and BMPs-1 through -5 and -7 levels were unchanged. The results were confirmed by sequence determination of the PCR product and by Northern blot analysis for total RNA. 17beta-estradiol increased BMP-6 protein production sixfold by Western analysis. Cotreatment with antiestrogens (ICI 182,780 or 4-hydroxytamoxifen) antagonized the effects of 17beta-estradiol. These data suggest that some of the skeletal effects of estrogen on bone and cartilage may be mediated by increased production of BMP-6 by osteoblasts.

Blotting, Northern↗
PubMed1998

Monitoring estrogen replacement therapy and identifying rapid bone losers with an immunoassay for deoxypyridinoline.

We have assessed urinary deoxypyridinoline (Dpd) levels by immunoassay in women who participated in a double-masked, placebo-controlled trial of the bone loss prevention effects of estrogen replacement therapy (ERT). Ninety-one women who had undergone recent surgical menopause were randomized to receive either placebo or 0.025, 0.05 or 0.1 mg/day transdermal 17 beta-estradiol for 2 years. Mean Dpd levels in the postmenopausal women were significantly elevated (p < 0.0001) above mean Dpd levels in a reference population of healthy, premenopausal women. Subjects in the placebo group lost 6.4% of lumbar spine bone mineral density (BMD) and 4.9% of mid-radius bone mineral content (BMC) over 2 years. Dpd levels at baseline were inversely correlated with BMD and BMC changes in the placebo group. The placebo group and subjects receiving 0.025 mg/day 17 beta-estradiol who had Dpd levels increased above the reference interval cut-off (mean + 2 standard deviations, 7.5 nmol/mmol) lost 2 times more bone mass than did those with Dpd levels below it. Dpd levels decreased significantly (p < 0.01) from baseline at 6 months following initiation of treatment with 0.05 or 0.1 mg/day 17 beta-estradiol, changes that correlated with increased lumbar spine BMD and with changes in mid-radius BMC. At 12 months, Dpd levels were lower than baseline and placebo in all three treatment groups. These data suggest utility of this Dpd immunoassay in assessing changes in bone resorption induced by surgical menopause and ERT.

Amino Acids↗