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Oogathoo S, Duchesne L, Houle D, Kneeshaw D. Characterizing Seasonal Radial Growth Dynamics of Balsam Fir in a Cold Environment Using Continuous Dendrometric Data: A Case Study in a 12-Year Soil Warming Experiment. SENSORS 2022; 22:s22145155. [PMID: 35890836 PMCID: PMC9315762 DOI: 10.3390/s22145155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/05/2022] [Accepted: 07/07/2022] [Indexed: 12/10/2022]
Abstract
Historical temperature records reveal that the boreal forest has been subjected to a significant lengthening of the thermal growing season since the middle of the last century, and climate models predict that this lengthening will continue in the future. Nevertheless, the potential phenological response of trees to changes in growing season length remains relatively undocumented, particularly for evergreen boreal tree species growing in cold environments. Here, we used the recently defined zero growth (ZG) concept to extract and characterize the metrics of seasonal radial growth dynamics for 12 balsam fir trees subjected to a 12-year soil warming experiment using high resolution radius dendrometer measurements. The ZG concept provides an accurate determination of growth seasonality (onset, cessation, duration, growth rates, and total growth) for these slow-growing trees characterized by significant shrinkage in tree diameter due to dehydration in the winter. Our analysis revealed that, on average, growth onset starts at day 152 ± 7 (±1 SE, 31 May–1 June) and ceases at day 244 ± 27 (31 August–1 September), for a growing season duration of about 3 months (93 ± 26 days) over a 12-year period. Growing season duration is mainly determined by growth cessation, while growth onset varies little between years. A large part (80%) of the total growth occurs in the first 50 days of the growing season. Given the dynamics of growth, early growth cessation (shorter growing season) results in a higher average seasonal growth rate, meaning that longer growing seasons are not necessarily associated with greater tree growth. Soil warming induces earlier growth cessation, but increases the mean tree growth rate by 18.1% and the total annual growth by 9.1%, on average, as compared to the control trees. Our results suggest that a higher soil temperature for warmed trees contributes to providing better growth conditions and higher growth rates in the early growing season, when the soil temperature is low and the soil water content is elevated because of snowmelt. Attaining a critical soil temperature earlier, coupled with lower soil water content, may have contributed to the earlier growth cessation and shorter growing season of warmed trees.
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Steenhuisen F, van den Heuvel-Greve M. Exposure radius of a local coal mine in an Arctic coastal system; correlation between PAHs and mercury as a marker for a local mercury source. ENVIRONMENTAL MONITORING AND ASSESSMENT 2021; 193:499. [PMID: 34291327 PMCID: PMC8295130 DOI: 10.1007/s10661-021-09287-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 07/12/2021] [Indexed: 05/26/2023]
Abstract
Mercury in the Arctic originates from emissions and releases at lower latitudes and, to a lesser extent, from local and regional sources. The relationship between mercury (Hg) and polycyclic aromatic hydrocarbons (PAHs) in sediment can be applied as an indicator of the mercury source. This research examines the Hg contamination gradient from a land-based coal mine to the surrounding coastal environment to quantify the impact of local sources. Total mercury and PAH (Σ14PAH) were measured in terrestrial and marine sediments as well as in marine biota. Samples were collected at the mine and two reference sites. Mercury and Σ14PAH concentrations in samples collected at the mine site were significantly higher than those at the reference sites. This was also found in the biota samples, although less pronounced. This work addresses the complexities of interpreting data concerning very low contaminant levels in a relatively pristine environment. A clear correlation between PAH and Hg concentration in sediment was found, although a large number of samples had levels below detection limits. PAH profiles, hierarchical clustering, and molecular diagnostic ratios provided further insight into the origin of PAHs and Hg, showing that signatures in sediments from the nearest reference site were more similar to the mine, which was not the case for the other reference site. The observed exposure radius from the mine was small and diluted from land to water to marine biota. Due to low contamination levels and variable PAH profiles, marine biota was less suitable for tracing the exposure radius for this local land-based Hg source. With an expected increase in mobility and availability of contaminants in the warming Arctic, changes in input of PAHs and Hg from land-based sources to the marine system need close monitoring.
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Kuang G, Yi H, Zhu M, Zhou J, Shang X, Zhao Z, Zhu C, Liao Q, Guan S, Zhang L. Study of Absorption Characteristics of the Total Saponins from Radix Ilicis Pubescentis in an In Situ Single-Pass Intestinal Perfusion (SPIP) Rat Model by Using Ultra Performance Liquid Chromatography (UPLC). Molecules 2017; 22:molecules22111867. [PMID: 29104273 PMCID: PMC6150237 DOI: 10.3390/molecules22111867] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 10/13/2017] [Accepted: 10/21/2017] [Indexed: 12/17/2022] Open
Abstract
In contrast to the extensively reported therapeutic activities, far less attention has been paid to the intestinal absorption of the total saponins from Radix Ilicis Pubescentis (in Chinese Mao-Dong-Qing, MDQ). This study aimed to investigate the intestinal absorption characteristics of ilexgenin A (C1), ilexsaponin A1 (C2), ilexsaponin B1 (C3), ilexsaponin B2 (C4), ilexsaponin B3 (DC1), and ilexoside O (DC2) when administrated with the total saponins from MDQ (MDQ-TS). An UPLC method for simultaneous determination of C1, C2, C3, C4, DC1, and DC2 in intestinal outflow perfusate was developed and validated. The absorption characteristics of MDQ-TS were investigated by evaluating the effects of intestinal segments, drug concentration, P-glycoprotein (P-gp) inhibitor (verapomil), endocytosis inhibitor (amantadine) and ethylene diamine tetraacetic acid (EDTA, tight junction modulator) on the intestinal transportation of MDQ-TS by using a single-pass intestinal perfusion (SPIP) rat model, and the influence of co-existing components on the intestinal transport of the six saponins was discussed. The results showed that effective apparent permeability (Papp) of C1, C2, C3, C4, and DC2 administrated in MDQ-TS form had no segment-dependent changes at low and middle dosage levels. C1, C2, C3, D4, DC1, and DC2 administrated in MDQ-TS form all exhibited excellent transmembrane permeability with Papp > 0.12 × 10−2 cm·min−1. Meanwhile, Papp and effective absorption rate constant (Ka) values for the most saponins showed concentration dependence and saturation characteristics. After combining with P-gp inhibitor of verapamil, Papp of C2, C3, and DC1 in MDQ-TS group was significantly increased up to about 2.3-fold, 1.4-fold, and 3.4-fold, respectively in comparison to that of non-verapamil added group. Verapamil was found to improve the absorption of C2, C3, and DC1, indicating the involvement of an active transport mechanism in the absorption process. Compared with the non-amantadine added group, the absorption of C1, C2, C4, DC1, and DC2 were decreased by 40%, 71%, 31%, 53%, and 100%, respectively. Papp for the six target compounds increased up to about 1.2–2.1-fold in comparison with the non-EDTA added, respectively. The gastrointestinal transport of MDQ-TS could be greatly promoted by EDTA, and inhibited by amantadine, implying that the intestinal absorption of MDQ-TS was by passive diffusion and endocytosis process. Compared with monomer administration group, the intestinal absorption of C3, C4, DC1, and DC2 was significantly improved by co-existing components in MDQ-TS, and the non-absorbable saponins of C4, DC1, and DC2 unexpectedly showed sufficient intestinal permeability with Papp > 0.12 × 10−2 cm·min−1. This suggested that compounds orally administrated in TCM extract forms displayed unique intestinal absorption characteristics different from those of monomers, and the enhancing intestinal absorption of MDQ-TS reflected a holistic and specific view of traditional Chinese medicines (TCMs).
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Lawson EA, Ackerman KE, Estella NM, Guereca G, Pierce L, Sluss PM, Bouxsein ML, Klibanski A, Misra M. Nocturnal oxytocin secretion is lower in amenorrheic athletes than nonathletes and associated with bone microarchitecture and finite element analysis parameters. Eur J Endocrinol 2013; 168:457-64. [PMID: 23258269 PMCID: PMC3679669 DOI: 10.1530/eje-12-0869] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
OBJECTIVE Preclinical data indicate that oxytocin, a hormone produced in the hypothalamus and secreted into the peripheral circulation, is anabolic to bone. Oxytocin knockout mice have severe osteoporosis, and administration of oxytocin improves bone microarchitecture in these mice. Data suggest that exercise may modify oxytocin secretion, but this has not been studied in athletes in relation to bone. We therefore investigated oxytocin secretion and its association with bone microarchitecture and strength in young female athletes. DESIGN Cross-sectional study of 45 females, 14-21 years (15 amenorrheic athletes (AA), 15 eumenorrheic athletes (EA), and 15 nonathletes (NA)), of comparable bone age and BMI. METHODS We used high-resolution peripheral quantitative CT to assess bone microarchitecture and finite element analysis to estimate bone strength at the weight-bearing distal tibia and non-weight-bearing ultradistal radius. Serum samples were obtained every 60 min, 2300-0700 h, and pooled for an integrated measure of nocturnal oxytocin secretion. Midnight and 0700 h samples were used to assess diurnal variation of oxytocin. RESULTS Nocturnal oxytocin levels were lower in AA and EA than in NA. After controlling for estradiol, the difference in nocturnal oxytocin between AA and NA remained significant. Midnight and 0700 h oxytocin levels did not differ between groups. At the tibia and radius, AA had impaired microarchitecture compared with NA. In AA, nocturnal oxytocin correlated strongly with trabecular and cortical microarchitecture, particularly at the non-weight-bearing radius. In regression models that include known predictors of microarchitecture in AA, oxytocin accounted for a substantial portion of the variability in microarchitectural and strength parameters. CONCLUSIONS Nocturnal oxytocin secretion is low in AA compared with NA and associated with site-dependent microarchitectural parameters. Oxytocin may contribute to hypoestrogenemic bone loss in AA.
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Walsh JS, Paggiosi MA, Eastell R. Cortical consolidation of the radius and tibia in young men and women. J Clin Endocrinol Metab 2012; 97:3342-8. [PMID: 22761460 DOI: 10.1210/jc.2012-1677] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Bone size, geometry, density, and microarchitecture are important determinants of bone strength. By understanding how these properties change during skeletal development, we can better understand bone fragility. OBJECTIVES The aim of the study was to compare the geometry, microarchitecture, and strength of the radius and tibia in men and women at the end of adolescence and in young adulthood and to relate these properties to biochemical bone turnover markers and bone regulatory hormones. DESIGN We conducted a cross-sectional study of 116 healthy men and women ages 16-18 (n = 56) and 30-32 (n = 60) yr. OUTCOME MEASURES We used high-resolution peripheral quantitative computed tomography to measure bone size, geometry, and microarchitecture at the distal radius and tibia and micro-finite element modeling to estimate bone strength. We measured bone turnover markers (β C-terminal telopeptide of type I collagen and amino-terminal propeptide of type I procollagen) and hormones known to affect bone metabolism (estradiol, testosterone, IGF-I, and PTH). RESULTS Bone strength was greater in men than in women, and at the radius it was greater in men ages 30-32 yr than ages 16-18 yr. The gender difference was due to greater cortical perimeter, trabecular area, and trabecular density in men. The age difference was due to greater cortical thickness and cortical tissue mineral density and lower cortical porosity. IGF-I was related to two of these five key properties at the radius (cortical perimeter and cortical thickness). None of the hormones were predictors of density or structure at the tibia. CONCLUSIONS Cortical modeling of long bones continues beyond the end of adolescence. IGF-I may be a determinant of this process at the radius.
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Abstract
OBJECTIVE Our aim was to determine whether the level of plasma total ghrelin varies with the menopause stage (pre-, peri-, and postmenopause). PARTICIPANTS AND INTERVENTIONS Women were divided in three groups: premenopausal, perimenopausal and postmenopausal. All participants had bone mineral densitometry and blood assay of plasma ghrelin, estradiol E2. Correlation between plasma ghrelin levels, their reproductive status and BMD was done. RESULTS The mean plasma level of ghrelin was significantly decreased in the perimenopausal and postmenopausal groups in comparison to the premenopausal group. A significant positive correlation was found between ghrelin and each of E₂ and BMD (at one or more of the three sites assessed) in all subjects, as well as, in peri- and postmenopausal women, whereas a significant negative correlation was found between ghrelin and FSH. CONCLUSION It may be assumed that ghrelin can affect BMD. Whether ghrelin and estrogen work independent or through convergent mechanisms needs further studies.
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Kalkwarf HJ, Gilsanz V, Lappe JM, Oberfield S, Shepherd JA, Hangartner TN, Huang X, Frederick MM, Winer KK, Zemel BS. Tracking of bone mass and density during childhood and adolescence. J Clin Endocrinol Metab 2010; 95:1690-8. [PMID: 20194709 PMCID: PMC2853985 DOI: 10.1210/jc.2009-2319] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Accepted: 01/25/2010] [Indexed: 01/26/2023]
Abstract
CONTEXT Whether a child with low bone mineral density (BMD) at one point in time will continue to have low BMD, despite continued growth and maturation, is important clinically. The stability of a characteristic during growth is referred to as "tracking." OBJECTIVE We examined the degree of tracking in bone mineral content (BMC) and BMD during childhood and adolescence and investigated whether tracking varied according to age, sexual maturation, and changes in growth status. DESIGN We conducted a longitudinal study with measurements at baseline and annually for 3 yr. SETTING The Bone Mineral Density in Childhood Study was conducted at five clinical centers in the United States. STUDY PARTICIPANTS A total of 1554 girls and boys, ages 6-16 yr at baseline, participated in the study. MAIN OUTCOME MEASURES Whole body, spine, hip, and forearm BMC and BMD were measured by dual-energy x-ray absorptiometry, and age-, sex-, and race-specific Z-scores were calculated. Deviation from tracking was calculated as the Z-score at yr 3 minus baseline. RESULTS Correlations between Z-scores at baseline and yr 3 ranged from 0.76-0.88. Among children with a Z-score below -1.5 at baseline, 72-87% still had a Z-score below -1 after 3 yr. Age, sexual maturation, and deviations in growth status (P < 0.01) were associated with deviation from tracking; however, tracking was strongly evident even after adjusting for the effects of age, maturation, and growth. CONCLUSIONS Bone density showed a high degree of tracking over 3 yr in children and adolescents. Healthy children with low bone density will likely continue to have low bone density unless effective interventions are instituted.
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Min JY, Min KB, Paek D, Kang D, Cho SI. Age curves of bone mineral density at the distal radius and calcaneus in Koreans. J Bone Miner Metab 2010; 28:94-100. [PMID: 19634016 DOI: 10.1007/s00774-009-0110-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Accepted: 06/11/2009] [Indexed: 10/20/2022]
Abstract
This study evaluated age-related changes in bone mineral density (BMD) and identified the peak bone mineral density (PBMD) in Koreans. We recruited 2929 subjects, ranging in age from 5 to 86 years, from three regions: Seoul, Siwha, and Gwangyang. The BMD at the distal radius and calcaneus were measured with dual-energy X-ray absorptiometry, and anthropometric measures were also obtained. PBMD was calculated from the highest mean in each age group. The PBMD at the distal radius was 0.514 +/- 0.06 g/cm(2) in females and 0.598 +/- 0.07 g/cm(2) in males. Peak ages for both sexes were the thirties. For the calcaneus, PBMD was 0.509 +/- 0.09 g/cm(2) in females and 0.629 +/- 0.09 g/cm(2) in males. Peak ages were the thirties for females and the twenties for males. These results could facilitate international or interracial comparisons and be used as reference data to screen for osteoporosis in Koreans.
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Travison TG, Araujo AB, Esche GR, McKinlay JB. The relationship between body composition and bone mineral content: threshold effects in a racially and ethnically diverse group of men. Osteoporos Int 2008; 19:29-38. [PMID: 17660933 PMCID: PMC2664109 DOI: 10.1007/s00198-007-0431-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2007] [Accepted: 06/20/2007] [Indexed: 01/15/2023]
Abstract
UNLABELLED We examined BMC and body composition in 1,209 black, Hispanic, and white men. Weight, BMI, waist circumference, and fat mass were associated with BMC only up to certain thresholds, whereas lean mass exhibited more consistent associations. The protective influence of increased weight appears to be driven by lean mass. INTRODUCTION Reduced body size is associated with decreased bone mass and increased fracture risk, but associations in men and racially/ethnically diverse populations remain understudied. We examined bone mineral content (BMC) at the hip, spine, and forearm as a function of body weight, body mass index (BMI), waist circumference, fat mass (FM), and nonbone lean mass (LM). METHODS The design was cross-sectional; 363 non-Hispanic black, 397 Hispanic, and 449 non-Hispanic white residents of greater Boston participated (N = 1,209, ages 30-79 y). BMC, LM, and FM were measured by DXA. Multiple linear regression was used to describe associations. RESULTS Weight, BMI, waist circumference, and FM were associated with BMC only up to certain thresholds. LM, by contrast, displayed strong and consistent associations; in multivariate models, femoral neck BMC exhibited a 13% increase per 10 kg cross-sectional increase in LM. In models controlling for LM, positive associations between BMC and other body composition measures were eliminated. Results did not vary by race/ethnicity. CONCLUSIONS The protective effect of increased body size in maintaining bone mass is likely due to the influence of lean tissue. These results suggest that maintenance of lean mass is the most promising strategy in maintaining bone health with advancing age.
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Ethier ALM, Braune BM, Scheuhammer AM, Bond DE. Comparison of lead residues among avian bones. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2007; 145:915-9. [PMID: 16815605 DOI: 10.1016/j.envpol.2006.05.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2006] [Revised: 04/28/2006] [Accepted: 05/01/2006] [Indexed: 05/10/2023]
Abstract
To determine if significant differences exist in lead (Pb) accumulation in different bones, especially those most often used for bone-Pb studies in wildlife, we compared Pb concentrations in radius, ulna, humerus, femur, and tibia of Common Eider (Somateria mollissima); and radius/ulna (combined), femur, and tibia of American Woodcock (Scolopax minor). There were no significant differences in bone-Pb concentrations among woodcock bones over a wide range of Pb concentrations (3-311 microg/g). In eider, where bone-Pb concentrations were low (<10 microg/g), leg bones had significantly higher Pb concentrations (approximately 30-40%) than wing bones from the same individuals. The variation among individual birds was greater than the variation among different bones within a bird. Based on our findings, we conclude that one type of bone may be substituted for another in bone-Pb studies although the same bone type should be analyzed for all birds within a study, whenever possible.
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Rittweger J, Frost HM, Schiessl H, Ohshima H, Alkner B, Tesch P, Felsenberg D. Muscle atrophy and bone loss after 90 days' bed rest and the effects of flywheel resistive exercise and pamidronate: results from the LTBR study. Bone 2005; 36:1019-29. [PMID: 15811637 DOI: 10.1016/j.bone.2004.11.014] [Citation(s) in RCA: 182] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2004] [Revised: 11/22/2004] [Accepted: 11/23/2004] [Indexed: 11/17/2022]
Abstract
Muscle atrophy and bone loss pose substantial problems for long-term space flight and in clinical immobilization. We therefore tested the efficacy of flywheel resistive exercise and pamidronate to counteract such losses. Twenty five young healthy males underwent strict bed rest with -6 degrees head-down tilt for 90 days. Subjects were randomized into an exercise group that practiced resistive exercise with a 'flywheel' (FW) device every 2-3 days, a pamidronate group (Pam) that received 60 mg pamidronate i.v. 14 days prior to bed rest and a control group (Ctrl) that received none of these countermeasures. During the study, Ca(++) and protein intake were controlled. Peripheral quantitative computed tomography (pQCT) was used to assess bone mineral content (BMC) and muscle cross sectional area (mCSA) of calf and forearm. Measurements were taken twice during baseline data collection, after 28 and after 89 days bed rest, and after 14 days recovery. On the same days, urinary Pyridinoline excretion and serum levels of alkaline phosphatase, Ca(++) and PTH were measured. Pre-study exercise habits were assessed through the Freiburg questionnaire. Losses in calf mCSA were significantly reduced in FW (Ctrl: -25.6% +/- 2.5% Pam: -25.6% +/- 3.7%, FW: -17.3% +/- 2.7%), but not in the forearm mCSA (Ctrl: -6.4% +/- 4.33%, Pam: -7.7% +/- 4.1%, FW: -7.6% +/- 3.3%). Both diaphyseal and epiphyseal BMC losses of the tibia were mitigated in Pam and FW as compared to Ctrl, although this was significant only at the diaphysis. Inter-individual variability was significantly greater for changes in BMC than in mCSA, and correlation of BMC losses was poor among different locations of the tibia. A significant positive correlation was found between change in tibia epiphyseal BMC and serum cortisol levels. These findings suggest that both countermeasures are only partly effective to preserve BMC (FW and Pam) and mCSA (FW) of the lower leg during bed rest. The partial efficacy of flywheel exercise as well as the bones' response to unloading per se underlines the importance of mechanical stimuli. The huge variability of BMC changes, however, suggests that other factors affect changes in whole-bone strength following acute mechanical disuse.
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Rodrigues ED, Pimentel ER, Mourão PAS, Gomes L. Distribution of small proteoglycans and glycosaminoglycans in humerus-related articular cartilage of chickens. Braz J Med Biol Res 2005; 38:381-90. [PMID: 15761618 DOI: 10.1590/s0100-879x2005000300009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The expression of components present in the cartilaginous extracellular matrix is related to development, gender, and genotype, as well as to the biomechanical properties of each type of cartilage. In the present study, we analyzed small proteoglycans and glycosaminoglycans present in different cartilages of the chicken wing after extraction with guanidine hydrochloride or papain. Quantitative analysis of glycosaminoglycans showed a larger amount in humeral cartilage (around 200 mg/g tissue) than in articular cartilage of the radius and ulna, with 138 and 80 mg/g tissue, respectively. Non-collagenous proteins isolated were predominantly from cartilage in the proximal regions of the humerus and radius. D4 fractions obtained by ultracentrifugation were separated by DEAE-Sephacel and Octyl-Sepharose chromatography and analyzed by SDS-PAGE. Two bands of 57 and 70-90 kDa were observed for all samples treated with beta-mercaptoethanol. Immunoblotting of these proteins was positive for the small proteoglycans fibromodulin and decorin, respectively. Apparently, the 57-kDa protein is present in macromolecular complexes of 160 and 200 kDa. Chondroitin sulfate was detected in all regions. HPLC analysis of the products formed by chondroitinase AC and ABC digestion mainly revealed beta-D-glucuronic acid and N-acetyl beta-D-galactosamine residues. The 4-sulfation/6-sulfation ratio was close to 3, except for the proximal cartilage of the radius (2.5). These results suggest functional differences between the scapula-humerus, humerus-ulna, and humerus-radius joints of the chicken wing. This study contributes to the understanding of the physiology of cartilage and joints of birds under different types of mechanical stress.
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Skedros JG, Holmes JL, Vajda EG, Bloebaum RD. Cement lines of secondary osteons in human bone are not mineral-deficient: New data in a historical perspective. ACTA ACUST UNITED AC 2005; 286:781-803. [PMID: 16037990 DOI: 10.1002/ar.a.20214] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Using qualitative backscattered electron (BSE) imaging and quantitative energy dispersive X-ray (EDX) spectroscopy, some investigators have concluded that cement (reversal) lines located at the periphery of secondary osteons are poorly mineralized viscous interfaces with respect to surrounding bone. This conclusion contradicts historical observations of apparent highly mineralized (or collagen-deficient) cement lines in microradiographs. Such conclusions, however, may stem from unrecognized artifacts that can occur during scanning electron microscopy. These include specimen degradation due to high-energy beams and the sampling of electron interaction volumes that extend beyond target locations during EDX analysis. This study used quantitative BSE imaging and EDX analysis, each with relatively lower-energy beams, to test the hypothesis that cement lines are poorly mineralized. Undemineralized adult human femoral diaphyses (n = 8) and radial diaphyses (n = 5) were sectioned transversely, embedded in polymethyl methacrylate, and imaged in a scanning electron microscope for BSE and EDX analyses. Unembedded samples were also evaluated. Additional thin embedded samples were stained and evaluated with light microscopy and correlated BSE imaging. BSE analyses showed the consistent presence of a bright line (higher atomic number) coincident with the classical location and description of the cement line. This may represent relative hypermineralization or, alternatively, collagen deficiency with respect to surrounding bone. EDX analyses of cement lines showed either higher Ca content or equivalent Ca content when compared to distant osteonal and interstitial bone. These data reject the hypothesis that cement lines of secondary osteons are poorly mineralized.
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Arabi A, Nabulsi M, Maalouf J, Choucair M, Khalifé H, Vieth R, El-Hajj Fuleihan G. Bone mineral density by age, gender, pubertal stages, and socioeconomic status in healthy Lebanese children and adolescents. Bone 2004; 35:1169-79. [PMID: 15542043 DOI: 10.1016/j.bone.2004.06.015] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2003] [Revised: 04/08/2004] [Accepted: 06/25/2004] [Indexed: 11/22/2022]
Abstract
Gender, ethnicity, and lifestyle factors affect bone mass acquisition during childhood, thus the need for age- and sex-adjusted Z scores using ethnic-specific data for bone mineral density (BMD) measurement. This study aimed at establishing normative data for BMD in healthy Lebanese children and adolescents. Three hundred sixty-three healthy children aged 10 to 17 years (mean+/-SD: 13.1+/-2.0) were studied. BMD, bone mineral content (BMC), and lean mass were measured by dual-energy X-ray absorptiometry (DXA) using a Hologic 4500A device, and apparent volumetric BMD (BMAD) of the lumbar spine and the femoral neck were calculated. BMD, BMC, and BMAD were expressed by age groups and Tanner stages for boys and girls separately. There was a significant effect of age and puberty on all bone parameters, except at the femoral neck BMAD in boys. BMC and BMD were higher at cortical sites in boys, including subtotal body and hip; whereas, in girls, it was higher at a site more enriched in trabecular bone, namely the lumbar spine. At several skeletal sites, girls had significantly higher BMD adjusted for lean mass than boys. By the end of puberty, adolescents had a mean BMD that was 43-66% higher at the lumbar spine and 25-41% higher at cortical sites than pre-pubertal children, depending on the gender. Mean BMD values in the study group were significantly lower (P<0.01) than Western normative values, with Z scores ranging between -0.2 and -1.1. In both genders, children of lower socioeconomic status tended to have lower BMD than those from a higher socioeconomic background. This study allows additional insight into gender dimorphism in mineral accretion during puberty. It also provides a valuable reference database for the assessment of BMD in children with pubertal or growth disorders who are of Middle Eastern origin.
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Ezura Y, Kajita M, Ishida R, Yoshida S, Yoshida H, Suzuki T, Hosoi T, Inoue S, Shiraki M, Orimo H, Emi M. Association of multiple nucleotide variations in the pituitary glutaminyl cyclase gene (QPCT) with low radial BMD in adult women. J Bone Miner Res 2004; 19:1296-301. [PMID: 15231017 DOI: 10.1359/jbmr.040324] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2003] [Revised: 02/27/2004] [Accepted: 03/29/2004] [Indexed: 11/18/2022]
Abstract
UNLABELLED Correlation between 13 genetic variations of the glutaminyl-peptide cyclotransferase gene and adjusted aBMD was tested among 384 adult women. Among 13 variations with strong linkage disequilibrium, R54W showed a prominent association (p = 0.0003), which was more striking when examined among 309 elder subjects (> or =50 years; p = 0.0001). Contribution for postmenopausal bone loss was suggested. INTRODUCTION Alterations in homeostatic regulation of estrogen through the hypothalamus-pituitary-gonadal axis (HPG axis) importantly affect the pathogenesis of osteoporosis. Osteoporosis-susceptibility genes have been proposed in this hormonal axis, such as estrogen receptor genes and the gonadotropin-releasing hormone gene (GnRH). Here we report another example of genes: glutaminyl-peptide cyclotransferase gene (QPCT), an essential modifier of pituitary peptide hormones, including GnRH. MATERIALS AND METHODS Analyses of association of 13 single nucleotide polymorphisms (SNPs) at the QPCT locus with adjusted areal BMD (adj-aBMD) were carried out among 384 adult women. Linkage disequilibrium (LD) was analyzed by haplotype estimation and calculation of D' and r2. Multiple regression analysis was applied for evaluating the combined effects of the variations. RESULTS AND CONCLUSIONS LD analysis indicated strong linkage disequilibrium within the entire 30-kb region of the QPCT gene. Significant correlations were observed between the genotypes of the six SNPs and the radial adj-aBMD, among which R54W (nt + 160C>T) presented the most prominent association (p = 0.0003). Striking association was observed for these SNPs among the 309 subjects >50 years of age (R54W, p = 0.0001; -1095T>C, p = 0.0002; -1844C>T, p = 0.0002). Multiple regression analyses indicated that multiple SNPs in the gene might act in combination to determine the radial adj-aBMD. These results indicate that genetic variations in QPCT are the important factors affecting the BMD of adult women that contribute to susceptibility for osteoporosis. The data should provide new insight into the etiology of the disease and may suggest a new target to be considered during treatment.
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Karacan I, Aydin T, Ozaras N. Bone loss in the contralateral asymptomatic hand in patients with complex regional pain syndrome type 1. J Bone Miner Metab 2004; 22:44-7. [PMID: 14691686 DOI: 10.1007/s00774-003-0447-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2003] [Accepted: 05/09/2003] [Indexed: 10/26/2022]
Abstract
Regional osteoporosis was seen radiographically in clinically affected areas in patients with complex regional pain syndrome type 1 (CRPS1). The aim of the this study was to investigate whether bone loss developed in the contralateral hand in patients with unilateral CRPS1 of the hand. Thirty-two patients with CRPS1 of the hand were included in this study. Bone mineral density was measured in the left proximal femur and both ultradistal radiuses, using dual-energy X-ray absorptiometry. The subjects were classified as grades 1 to 3 according to the T-score of both ultradistal radiuses (densitometric grades): grade 1, both radiuses were normal; grade 2, bone loss was determined only in the affected radius; and grade 3, there was bone loss in both radiuses. Twenty (62.5%) patients had bone loss in the affected hand; 11 patients (34.4%) had bone loss only on the affected side and 9 patients (28.1%) had bone loss on both sides. The mean duration of the period between the diagnosis of the injury and the measurement of bone density was 1.9 +/- 0.6 months in patients with grade 1, 3.1 +/- 1.0 months in patients with grade 2, and 5.5 +/- 2.2 months in patients with grade 3. The Spearman test showed a significant correlation between the period of injury and the densitometric grade ( R = 0.774; P = 0.0001). In conclusion, the current study of patients with CRPS1, showed that the bone loss in the asymptomatic contralateral hand developed at a later stage than that in the affected hand. This bone loss was less frequent and of a lower degree in the asymptomatic contralateral hand than in the affected hand. The bone loss in the asymptomatic contralateral hand could be explained by the loss of sympathetic tone in CRPS1 and contralateral sympathetic innervation.
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Bonofiglio D, Garofalo C, Catalano S, Marsico S, Aquila S, Andò S. Low calcium intake is associated with decreased adrenal androgens and reduced bone age in premenarcheal girls in the last pubertal stages. J Bone Miner Metab 2004; 22:64-70. [PMID: 14691690 DOI: 10.1007/s00774-003-0451-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2002] [Accepted: 04/21/2003] [Indexed: 11/28/2022]
Abstract
In 50 premenarcheal girls selected from the lowest and highest end of the calcium-intake distribution of a large population sample, we evaluated bone mineral density (BMD), together with the following hormonal-metabolic parameters: androstenedione (ASD), dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), testosterone (T), estradiol (E2), the apparent free fractions of T (AFTC) and E2 (AFEC), osteocalcin (OC), parathyroid hormone (PTH), and 25-hydroxyvitamin D. Dietary calcium was assessed by 3-day food records, and BMD was measured at ultradistal (ud) and proximal (pr) radial sites, using dual-energy X-ray absorptiometry. Calcium intake, which was below the recommended levels set for the Italian population and below the recommended daily allowance (RDA) in both subgroups of girls, did not show any apparent relationship with ud- and pr- BMD. However, despite the similar chronological age of the two premenarcheal groups, in the low-calcium consumers, we found lower bone age, delayed pubertal development, and lower circulating adrenal androgens. Of interest, in girls who had a low calcium intake, PTH levels were significantly higher. In all premenarcheals, we observed that DHEA, T, and AFTC were positively correlated with bone age and with bone density at both radial sites. Even though bone density at the two radial sites did not show any apparent relationship to calcium consumption, the increased mean PTH in the girls with low calcium intake seems to underscore the hormonal attempt in maintaining calcium homeostasis. In conclusion, low calcium intake and reduced levels of adrenal androgens, leading to decreased bone age and delayed pubertal development, indicate a link between calcium intake, the hormonal milieu, and skeletal maturation.
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Nielsen SP, Bärenholdt O, Bärenholdt-Schiøler C, Mauras Y, Allain P. Noninvasive measurement of bone strontium. J Clin Densitom 2004; 7:262-8. [PMID: 15319495 DOI: 10.1385/jcd:7:3:262] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2003] [Revised: 03/11/2004] [Accepted: 03/29/2004] [Indexed: 11/11/2022]
Abstract
The strontium content of bone has hitherto been impossible to measure noninvasively. A novel dual-photon absorptiometry (DPA) method was developed. 241Am (59.5 keV) and 133Ba (356 keV) were used as radiation sources. The linearity of the DPA method was studied in monkey bones ex vivo after treatment over 52 wk with strontium ranelate. The bone strontium expressed in terms of the percentage molar ratio SrHA/(SrHA + CaHA) x 100%, where HA denotes hydroxyapatite, was measured (1) by the DPA method and (2) by inductively coupled plasma-atomic emission spectrophotometry at the same distal site of the femur. The results correlated significantly: y = 0.33%Sr + 1.086x; r = 0.976; standard error of the estimate (SEE) = 0.57%Sr. In order to measure the accuracy error of Sr%, 30 normal volunteers were measured. Their mean values did not differ significantly from zero and the SD was 0.5%. The radiation dose was small, the equivalent whole-body dose to human subjects being 0.005 micro Sv. This novel DPA method is likely to be successful for bone strontium measurement in humans.
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Havill LM, Mahaney MC, Czerwinski SA, Carey KD, Rice K, Rogers J. Bone mineral density reference standards in adult baboons (Papio hamadryas) by sex and age. Bone 2003; 33:877-88. [PMID: 14678847 DOI: 10.1016/s8756-3282(03)00231-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Osteoporosis is a progressive condition involving structural deterioration of bone tissue, leading to skeletal fragility and an increased susceptibility to fractures due to low bone mass and high rates of bone turnover. Areal bone mineral density (aBMD) serves as the most reliable predictor of susceptibility to osteoporotic fracture. The development of animal models, including Old World Monkeys, has been essential to studies of bone mineral density. These animals, including the baboon, exhibit many biological similarities with our own species relevant to the variation in age-related changes and pathology in bone that may make them an excellent model for studies of skeletal structure and maintenance in humans. The baboon has been shown to exhibit extensive biological similarities to humans regarding skeletal biology, but little is known about the range of normal variation in skeletal traits, such as bone mineral density, in this species. Our data, collected on baboons (Papio hamadryas) that are part of a large breeding colony at the Southwest Foundation for Biomedical Research and the Southwest National Primate Research Center (San Antonio, TX), involve 466 females and 210 males, ranging in age from 5.5 to 30 years. Student's t tests, bivariate correlations, and likelihood ratio tests show sex and age effects at all spinal sites. Age effects are minimal or absent in the forearm sites. This study is the first to characterize normal variation in aBMD in baboons, to assess the effect of age and sex on this variation, and to compare this variation to those data currently available from experimental control animals. As such, it provides much-needed reference standards that will allow researchers to evaluate the status of their animals in cross-sectional studies and more fully assess the meaning of aBMD changes in longitudinal studies.
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Lind PM, Bergman A, Olsson M, Orberg J. Bone mineral density in male Baltic grey seal (Halichoerus grypus). AMBIO 2003; 32:385-8. [PMID: 14627366 DOI: 10.1579/0044-7447-32.6.385] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Bone mineral density (mg cm(-3)) was studied in male Baltic grey seals (4-23 years of age) by noninvasive computed tomography (pQCT). The material was grouped according to year of collection. Group A: 1850-1955, a period before the main introduction of organochlorines (OCs); Group B: 1965-1985, a period with very high OC contamination; and Group C: 1986-1997, a period with decreasing concentrations of OCs. The reproducibility of the measurements was good with a Coefficient of Variation (CV) ranging from 0.1% to 2.1%. Trabecular bone mineral density of the radius was significantly higher in specimens collected 1986-1997 than in those collected 1965-1985 (p < 0.05). Cortical bone mineral density of the mandible was significantly lower in specimens collected 1986-1997 compared with those collected 1850-1955 (p < 0.05). These results indicate different responses over time in trabecular and cortical bone. During the period of very high OC contamination (1965-1985), trabecular bone density was lowest, whereas cortical bone density was lowest in specimens collected 1985-1997, representing a period of fairly low OC contamination. The mechanisms behind these effects are not known. However, it can be assumed that OCs are involved. Information about residue levels of OCs in the studied individuals is lacking and, therefore, it was not possible to evaluate the impact of OCs in this respect.
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Yano S, Sugimoto T, Tsukamoto T, Yamaguchi T, Hattori T, Sekita KI, Kaji H, Hattori S, Kobayashi A, Chihara K. Effect of parathyroidectomy on bone mineral density in hemodialysis patients with secondary hyperparathyroidism: possible usefulness of preoperative determination of parathyroid hormone level for prediction of bone regain. Horm Metab Res 2003; 35:259-64. [PMID: 12778370 DOI: 10.1055/s-2003-39483] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
PURPOSE To examine longitudinal changes of bone mineral density (BMD) after parathyroidectomy (PTx) in patients undergoing maintenance hemodialysis (HD) with severe secondary hyperparathyroidism (HPT) to determine which factor contributes most to bone changes. METHODS Fifteen Japanese HD patients who had been refractory to medical therapy were subject to PTx with autotransplantation. We measured BMD by dual energy X-ray absorptiometry (DXA) at the lumbar spine (L2 - 4 BMD) and the distal 1/3 region of the radius (1/3R BMD) at 1, 3, 6, 12, 24, and 36 months after PTx. RESULTS Baseline Z-score of BMD was markedly low at 1/3R (- 3.07) and slightly low at L2 - 4 (-0.59) in this group. A significant increase in L2 - 4 BMD was observed as early as one month after PTx, which was sustained afterwards. Annual percent changes in L2 - 4 and 1/3R BMD were + 15.6 % and + 6.4 %, respectively. The annual percent changes in BMD at both sites were positively associated with preoperative intact PTH levels (L2 - 4; r = 0.642, p = 0.010, 1/3R; r = 0.884, p < 0.001) and total alkaline phosphatase (ALP) levels (L2 - 4; r = 0.663, p = 0.007, 1/3R; r = 0.858, p < 0.001). Stepwise multiple regression analysis revealed that serum levels of intact PTH and ALP were the best predictors of both percentage and net changes in radial BMD with high determination coefficients (r 2 > 0.8). CONCLUSION Successful PTx following appropriate supplementation with vitamin D and calcium provides a marked increase in lumbar BMD and a modest increase in radial BMD in HD patients with secondary HPT. Preoperative levels of PTH and ALP are useful for predicting postoperative changes in bone mass.
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Kajita M, Ezura Y, Iwasaki H, Ishida R, Yoshida H, Kodaira M, Suzuki T, Hosoi T, Inoue S, Shiraki M, Orimo H, Emi M. Association of the -381T/C promoter variation of the brain natriuretic peptide gene with low bone-mineral density and rapid postmenopausal bone loss. J Hum Genet 2003; 48:77-81. [PMID: 12601551 DOI: 10.1007/s100380300010] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Osteoporosis is believed to result from interplay among multiple environmental and genetic determinants, including factors that regulate bone-mineral density (BMD). Recent quantitative trait locus analysis in human suggested a possible involvement of chromosomal region 1p36.2-p36.3 for determination of BMD. The brain natriuretic peptide (BNP, also named NPPB) gene lies within this candidate region for BMD determination. Overexpression of the BNP resulted in skeletal overgrowth in transgenic mice. Association analysis between nucleotide variations of the BNP gene and radial BMD in 378 Japanese postmenopausal women revealed a significant association of the -381T/C variation of the BNP gene with radial BMD (r = 0.17, P = 0.01). Homozygous T-allele carriers had the lowest BMD values (0.395 +/- 0.056 g/cm(2)), homozygous C-allele carriers had the highest (0.429 +/- 0.051 g/cm(2)), and heterozygous individuals had intermediate radial BMD values (0.405 +/- 0.048 g/cm(2)), indicating a dosage effect. Accelerated bone loss also correlated with the -381 T allele in a 5-year follow-up study (r = 0.21, P = 0.017). These results suggest that variation of BNP may be an important determinant of postmenopausal osteoporosis, in part through the mechanism of accelerated postmenopausal bone loss.
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Yamamura JI, Aoe S, Toba Y, Motouri M, Kawakami H, Kumegawa M, Itabashi A, Takada Y. Milk basic protein (MBP) increases radial bone mineral density in healthy adult women. Biosci Biotechnol Biochem 2002; 66:702-4. [PMID: 12005077 DOI: 10.1271/bbb.66.702] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We studied the effects of daily intake of milk basic protein (MBP) on radial bone mineral density (BMD) in healthy adult women. Thirty-three healthy women were randomly assigned to a 6-month trial with either placebo or MBP (40 mg per day). The radial BMD of each volunteer was measured at the beginning of and at six months after the trial. The mean BMD value at the 6th month in the MBP group increased significantly at both 1/6 and 1/10 portion from the distal end of the radius, whereas that in the control group did not. The BMD gain of each volunteer in the MBP group was significantly higher than that in the placebo group. Thus a daily MBP supplementation of 40 mg in healthy adult women can significantly increase radial BMD.
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Eckstein F, Lochmüller EM, Lill CA, Kuhn V, Schneider E, Delling G, Müller R. Bone strength at clinically relevant sites displays substantial heterogeneity and is best predicted from site-specific bone densitometry. J Bone Miner Res 2002; 17:162-71. [PMID: 11771664 DOI: 10.1359/jbmr.2002.17.1.162] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
In this study we test the hypotheses that mechanical bone strength in elderly individuals displays substantial heterogeneity among clinically relevant skeletal sites, that ex situ dual-energy X-ray absorptiometry (DXA) provides better estimates of bone strength than in situ DXA, but that a site-specific approach of bone densitometry is nevertheless superior for optimal prediction of bone failure under in situ conditions. DXA measurements were obtained of the lumbar spine, the left femur, the left radius, and the total body in 110 human cadavers (age, 80.6 +/- 10.5 years; 72 female, 38 male), including the skin and soft tissues. The bones were then excised, spinal and femoral DXA being repeated ex situ. Mechanical failure tests were performed on thoracic vertebra 10 and lumbar vertebra 3 (compressive loading of a functional unit), the left and right femur (side impact and vertical loading configuration), and the left and right distal radius (fall configuration, axial compression, and 3-point-bending). The failure loads displayed only very moderate correlation among sites (r = 0.39 to 0.63). Ex situ DXA displayed slightly higher correlations with failure loads compared with those of in situ DXA, but the differences were not significant and relatively small. Under in situ conditions, DXA predicted 50-60% of the variability in bone failure loads at identical (or closely adjacent) sites, but only around 20-35% at distant sites, advocating a site-specific approach of densitometry. These data suggest that mechanical competence in the elderly is governed by strong regional variation, and that its loss in osteoporosis may not represent a strictly systemic process.
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Schanler RJ, Smith LG, Burns PA. Effects of long-term maternal intravenous magnesium sulfate therapy on neonatal calcium metabolism and bone mineral content. Gynecol Obstet Invest 2001; 43:236-41. [PMID: 9194621 DOI: 10.1159/000291864] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A prospective study was designed to determine whether calcium homeostasis and bone mineral content were affected adversely in preterm infants born to mothers receiving long-term antenatal therapy with magnesium sulfate. Preterm infants born to mothers receiving long-term antenatal therapy with magnesium sulfate and requiring prolonged bed rest for preterm labor were compared with infants of mothers not receiving magnesium sulfate but in whom prolonged bed rest was also required. Serum magnesium, calcium, phosphorus, osteocalcin, and parathyroid hormone were measured in infants at 0, 24, 48, and 72 h after delivery. Bone mineral content of the distal radius was measured 1 week postnatally and at term-equivalent postmenstrual age. Maternal serum mineral status indices obtained near delivery and bone indices were compared with those of their infants. The clinical characteristics and morbidities of the infants were similar between groups. We observed significantly greater serum concentrations of magnesium, phosphorus, and osteocalcin during the 72 h after delivery and a lower serum calcium concentration which normalized by 72 h in preterm infants whose mothers were treated with magnesium sulfate compared with infants whose mothers did not receive magnesium sulfate. Both groups, however, had similar radius bone mineral content measurements and anthropometric indices after delivery. These data suggest that although preterm infants born to mothers treated with magnesium sulfate have delayed clearance of magnesium and phosphorus, they have a normalization of serum calcium by 72 h after delivery and no significant differences in bone mineral content after delivery compared with infants whose mothers do not receive magnesium sulfate.
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