Obstructive sleep apnoea syndrome (OSAS) as a risk factor for secondary osteoporosis in children.

Repetitive hypoxia seen in obstructive sleep apnoea syndrome (OSAS) may affect bone metabolism increasing the risk for secondary osteoporosis. This study investigates the association between OSAS in children and secondary osteoporosis. This cross-sectional study included 150 children aged 10-17 years: 86 with OSAS and 64 with no OSAS. OSAS was confirmed by polysomnography. Quantitative ultrasound (QUS) of calcaneum measuring speed of sound (SoS) and broadband ultrasound attenuation (BUA) were collected. Other parameters collected including bone profile, vitamin D levels, physical activity scoring and dietary calcium intake. Majority were male and Malay ethnicity. OSAS children were mostly obese (84%) and 57% had moderate to severe OSAS. Most had lower physical activities scores. Mean (SD) phosphate and Alkaline phosphatase were lower in OSA children compared to controls: PO4, p = 0.039 and ALP, p < 0.001. Using both single and multivariate analysis, children with OSAS had a lower mean SoS value, p < 0.001 and p = 0.004 respectively after adjusting for age, BMI and bone profile. Children with OSAS had lower SoS suggesting risk for secondary osteoporosis. QUS calcaneus is a non-invasive, feasible tool and can be used to screen risk of osteoporosis in children. Further bone mineral density assessment is needed in these groups of children to confirm diagnosis of osteoporosis.

Tourniquet-induced ischemia and reperfusion in subcutaneous tissue, skeletal muscle, and calcaneal cancellous bone.

This study aimed to evaluated ischemic metabolites in subcutaneous tissue, skeletal muscle, and calcaneal cancellous bone before, during, and after tourniquet application in a simultaneous paired comparison of tourniquet-exposed and non-tourniquet-exposed legs. Ten patients scheduled for hallux valgus or hallux rigidus surgery were included. Microdialysis catheters were placed to simultaneously and continuously sample the metabolites glucose, lactate, pyruvate, and glycerol bilaterally for 12 h in subcutaneous tissue, skeletal muscle, and calcaneal cancellous bone. A tourniquet was applied on the leg planned for surgery (inflation time: 15 min, mean tourniquet duration time (range): 65 (58;77) min). During tourniquet inflation, a 2- to 3-fold increase of the mean lactate/pyruvate ratio was found for all investigated tissues in the tourniquet-exposed leg compared with the non-tourniquet-exposed leg. The lactate/pyruvate ratio recovery time after tourniquet release was within 30 min for skeletal muscle, 60 min for subcutaneous tissue, and 130 min for calcaneal cancellous bone. Only the tourniquet-exposed skeletal muscles were found to be ischemic during tourniquet inflation, defined by a significant increase of the lactate/pyruvate ratio exceeding the ischemic cutoff level of 25; however, this level decreased below 25 immediately after tourniquet release. The glycerol ratio increased instantly after inflation in the tourniquet-exposed leg in skeletal muscle and subcutaneous tissue, and recovered within 60 (skeletal muscle) and 130 min (subcutaneous tissue) after tourniquet release. These findings suggest that applying tourniquet for approximately 1 h results in limited tissue ischemia and cell damage in subcutaneous tissue, skeletal muscle, and calcaneal cancellous bone.

Diferencias en el metabolismo mineral óseo hiperparatiroidismo primario normocalcémico respecto al hiperparatiroidismo primario clásico / Differences in bone mineral metabolism normocalcemicprimary hyperparathyroidism with respect to classicalprimary hyperparathyroidism

OBJETIVO: El hiperparatiroidismo primario normocalcémico es una variedad menos conocida del hiperparatiroidismo primario clásico. Presentamos en este estudio sus manifestaciones clínicas y los datos relacionados con el metabolismo mineral óseo, tanto desde el punto de vista analítico como densitométrico, comparando los mismos con un grupo de pacientes afectos de hiperparatiroidismo primario clásico, con hipercalcemia. MATERIAL Y MÉTODOS: Estudio de casos y controles donde consideramos caso a pacientes afectos de hiperparatiroidismo primario normocalcémico (n=25) y control (n=25) a pacientes con hiperpartiroidismo primario con hipercalcemia (hiperparatiroidismo primario clásico). Se les efectuó una evaluación clínica completa con recogida de datos clínicos y realizándose determinaciones analíticas en sangre y orina de 24h, así como la estimación de la densidad mineral ósea y el trabecular bone score por densitometría (absorciometría radiológica dual, DXA) y los parámetros ultrasonográficos en el calcáneo. RESULTADOS: En el estudio clínico, los pacientes afectos de hiperparatiroidismo primario clásico solo muestran una mayor prevalencia de urolitiasis (OR: 9,333; IC 95%: 1,50-82,7) en comparación con los pacientes que sufren un hiperparatiroidismo primario normocalcémico. En todos los demás parámetros clínicos, analíticos, densitométricos y ultrasonográficos, no se aprecian diferencias estadísticamente significativas entre ambos grupos. CONCLUSIONES: Con la excepción de los niveles séricos de calcio y la prevalencia de urolitiasis, el hiperparatiroidismo normocalcémico cursa de manera indistinguible del hiperparatiroidismo clásico

OBJECTIVE: Normocalcemic primary hyperparathyroidism is a less known variety of classical primary hyperparathyroidism. In this paper, we present its clinical expression and data related to bone mineral metabolism, both analytically and densitometrically, comparing them with a group of patients with classic primary hyperparathyroidism, with hypercalcemia. MATERIAL AND METHODS: Study of cases and controls where we consider case of patients with normocalcemic primary hyperparathyroidism (n=25) and control (n=25) of patients with primary hyperpartyroidism with hypercalcemia (classical primary hyperparathyroidism). A complete clinical assessment was carried out with clinical data collection and24h blood and urine analytical determinations were performed, as well as estimating bone mineral density and trabecular bone score by densitometry (dual x‐ray absorptiometry, DXA) and ultrasound parameters in the calcaneus. RESULTS: In this clinical study, patients with classic primary hyperparathyroidism only show a higher prevalence of urolithiasis (OR: 9.333; 95% CI: 1.50‐82.7) compared to patients suffering from a normocalcemic primary hyperparathy‐roidism. In all other clinical, analytical, densitometric and ultrasonographic parameters, there are no statistically significant differences between the two groups. CONCLUSIONS: Apart from serum calcium levels and the prevalence of urolithiasis, normocalcemic hyperparathyroidism is indistinguishable from classical hyperparathyroidism

A case of ischemic osteopathy in a hemodialysis patient with advanced peripheral artery disease.

Peripheral artery disease (PAD) or arteriosclerosis obliterans is a lethal complication highly prevalent in pre-dialysis CKD and dialyzed patients. PAD is driven by atherosclerotic process and causes ischemia of the affected limb. Given that normal bone metabolism is based on sufficient blood supply and PAD decreases intraosseous blood flow of the affected limb, it is probable that PAD can directly cause ischemic osteopathy or osteoporosis in affected limbs. We herein present a 69-year-old female patient receiving 18 years of maintenance hemodialysis therapy was hospitalized for the treatment of bilateral PAD. Angiography showed a diffuse stenosis of the right superficial femoral artery and total occlusion of the left superficial femoral artery. Right ankle brachial index (ABI) was 0.83, whereas left ABI was unmeasurable. Notably, T score of the bone mineral density (BMD) in the right calcaneus measured by quantitative ultrasound was - 1.4, while that in the left calcaneus was - 2.2, showing a huge difference between BMD in the bilateral calcaneus. Metal stent was inserted to the right superficial femoral artery, whereas femoropopliteal bypass surgery was performed for the left limb. After the surgery, her right and left ABI were 0.96 and 0.92, respectively. Our case typically showed the clinical significance of sufficient blood supply to the bone for the normal bone metabolism and reminds us of the potential need to conduct further research on the association between PAD and ischemic osteopathy in patients with CKD.

Exercise-based correlates to calcaneal osteogenesis produced by a chronic training intervention.

Thirty workouts on a gravity-independent device (Impulse Training Systems, Newnan GA) evoked significant calcaneal bone mineral content (BMC, +29%) and density (BMD, +33%) gains. High speeds and impact loads were produced per repetition. We examined exercise performance variables from the 30-workout intervention to identify correlates to delta (∆) calcaneal BMC and BMD variance. Workouts included hip extension and seated calf press exercises done with subject's left legs. ∆ values were obtained from the first and 12th workouts for the hip extension movement, and for the first and 24th workouts for the seated calf press exercise. Per exercise the following variables were quantified: peak force (∆PF), peak acceleration (∆PA), impulse (∆I), and dwell times (∆DT). Dwell times are the elapsed time between the end of the eccentric phase, and the start of the next repetition's concentric phase. Pearson Coefficients assessed correlations between performance and criterion variables. With hip extension ∆DT calculated with data from the first and 12th workouts, there were significant correlations with calcaneal ∆BMC (r = -0.64) and ∆BMD (r = -0.63). With seated calf press ∆DT derived as the difference from the first and 24th workouts, there was a significant correlation with calcaneal ∆BMC (r = -0.48), but only a trend (r = -0.45) with ∆BMD as the criterion. No other variables correlated with significant amounts of calcaneal ∆BMC and ∆BMD variance. Negative correlations infer shorter dwell times evoked greater gains. The gravity-independent device warrants continued inquiry to treat and abate calcaneal losses.

Functional Adaptation of the Calcaneus in Historical Foot Binding.

The normal structure of human feet is optimized for shock dampening during walking and running. Foot binding was a historical practice in China aimed at restricting the growth of female feet for aesthetic reasons. In a bound foot the shock-dampening function normally facilitated by the foot arches is withdrawn, resulting in the foot functioning as a rigid extension of the lower leg. An interesting question inspiring this study regards the nature of adaptation of the heel bone to this nonphysiological function using the parameters of cancellous bone anisotropy and 3D fabric topology and a novel intertrabecular angle (ITA) analysis. We found that the trabecular microarchitecture of the normal heel bone, but not of the bound foot, adapts to function by increased anisotropy and preferred orientation of trabeculae. The anisotropic texture in the normal heel bone consistently follows the physiological stress trajectories. However, in the bound foot heel bone the characteristic anisotropy pattern fails to develop, reflecting the lack of a normal biomechanical input. Moreover, the basic topological blueprint of cancellous bone investigated by the ITA method is nearly invariant in both normal and bound foot. These findings suggest that the anisotropic cancellous bone texture is an acquired characteristic that reflects recurrent loading conditions; conversely, an inadequate biomechanical input precludes the formation of anisotropic texture. This opens a long-sought-after possibility to reconstruct bone function from its form. The conserved topological parameters characterize the generic 3D fabric of cancellous bone, which is to a large extent independent of its adaptation to recurrent loading and perhaps determines the mechanical competence of trabecular bone regardless of its functional adaptation. © 2017 American Society for Bone and Mineral Research.

Dietary antioxidant quality score (DAQs) is associated with bone mass assessed by calcaneal quantitative ultrasound in young women / El índice de calidad antioxidante de la dieta (DAQS) está asociado con la masa ósea evaluada mediante ultrasonido cuantitativo en el calcáneo en mujeres jóvenes

Introduction: Evidence suggests that intake of antioxidants could positively influence bone mass by preventing bone metabolism against oxidative stress. Objective: We aimed to investigate the possible influence of single antioxidant intakes and dietary antioxidant quality score (DAQs) on calcaneal quantitative ultrasound (QUS) in a population of young adults. Methods: A total of 605 young Spanish adults participated in this study (median age 20.38 ± 2.67). Bone mass was measured by calcaneal QUS to determine broadband ultrasound attenuation (BUA, dB/MHz) parameter. Body composition was assessed by bioelectrical impedance analysis and dietary intakes were determined using a 72-hour diet recall interview. DAQs was applied to calculate antioxidant nutrients intake. Linear regression analyses were performed to investigate the possible influence of DAQs on calcaneal QUS. Results: Most of young adults showed a low-quality antioxidant intake (only 17.6% of women and 20.3% of men had a score of 4 or 5 in DAQs). A positive correlation between DAQs and BUA was observed in women (r = 0.117; p = 0.024). Linear regression analysis revealed that DAQs was significantly associated with BUA parameter in women after adjusting by body weight, height, calcium intake and physical activity (PA) (p = 0.035). No significant associations between single antioxidant and calcaneus QUS measurement were found. Conclusion: Our findings suggest that high-quality antioxidant intakes could influence bone health in young women. Future studies should further investigate the protective role of antioxidant nutrients against osteoporosis (AU)

Introducción: la evidencia sugiere que la ingesta de antioxidantes podría influir positivamente en la masa ósea mediante la prevención contra el estrés oxidativo del metabolismo óseo. Objetivo: el objetivo fue investigar la posible influencia del consumo de antioxidantes y del índice de calidad antioxidante de la dieta (DAQs) en la masa ósea, evaluada mediante ultrasonido cuantitativo (QUS) en el calcáneo en una población de adultos jóvenes. Métodos: un total de 605 adultos jóvenes españoles participaron en este estudio (mediana 20,38 ± 2,67 años). La masa ósea se evaluó mediante QUS en el calcáneo para determinar el parámetro de atenuación de ultrasonido de banda ancha (BUA, dB/MHz). La composición corporal se determinó mediante bioimpedancia eléctrica y la ingesta dietética se determinó a través del recordatorio de 72 horas. El DAQs se aplicó para calcular la ingesta total de nutrientes antioxidantes. Se realizaron análisis de regresión lineal para investigar la posible influencia del DAQs en QUS en el calcáneo. Resultados: la mayoría de los adultos jóvenes mostraron una ingesta de antioxidantes de baja calidad (solo el 17,6% de las mujeres y el 20,3% de los hombres presentaron una puntuación de 4 o 5 en DAQs). Se observó una correlación positiva entre el DAQs y el BUA en las mujeres (r = 0,117; p = 0,024). El análisis de regresión lineal reveló que el DAQs se asociaba significativamente con el parámetro BUA en las mujeres después de ajustar por peso corporal, altura, ingesta de calcio y actividad física (p = 0,035). No se encontraron asociaciones significativas entre la ingesta de antioxidantes individuales y QUS en el calcáneo. Conclusión: nuestros resultados sugieren que una ingesta de antioxidantes de alta calidad podría infl uir en la salud ósea en mujeres jóvenes. Futuros estudios deben profundizar en el papel protector de los nutrientes antioxidantes contra la osteoporosis (AU)

Age and sex influence on bone and blood lead concentrations in a cohort of the general population living in Toronto.

OBJECTIVE: To study the age and sex influence on bone and blood lead concentrations in a cohort of the general population living in Toronto. APPROACH: A 109Cd K x-ray fluorescence (KXRF) measurement system was used from 2009 to 2011 in a study that measured the bone lead (Pb) concentration of 263 environmentally exposed individuals residing in Toronto, Ontario, Canada. Tibia (cortical bone) and calcaneus (trabecular bone) lead contents were measured in 134 males and 129 females between 1 and 82 years of age. Whole blood Pb concentration was measured by TIMS (thermal ionization mass spectrometer). Tibia (Ti) and calcaneus (Cal) Pb were examined versus the age of participants, taking into account uncertainties in bone Pb measurement values. MAIN RESULTS: No significant sex differences were observed in any of the age categories. Participants older than 50 years of age demonstrated the highest concentrations of Pb in their blood, tibia, and calcaneus bones. SIGNIFICANCE: In most of the previous publications, uncertainty was not considered in the regression model of bone Pb and age. However, in this paper, we adjusted the bone Pb values for the uncertainty level. This had a significant influence in regression models of bone Pb and thus we recommend that uncertainty be considered in future studies.

Urinary Mineral Concentrations in European Pre-Adolescent Children and Their Association with Calcaneal Bone Quantitative Ultrasound Measurements.

This study investigates differences and associations between urinary mineral concentrations and calcaneal bone measures assessed by quantitative ultrasonography (QUS) in 4322 children (3.1-11.9 years, 50.6% boys) from seven European countries. Urinary mineral concentrations and calcaneal QUS parameters differed significantly across countries. Clustering revealed a lower stiffness index (SI) in children with low and medium urinary mineral concentrations, and a higher SI in children with high urinary mineral concentrations. Urinary sodium (uNa) was positively correlated with urinary calcium (uCa), and was positively associated with broadband ultrasound attenuation and SI after adjustment for age, sex and fat-free mass. Urinary potassium (uK) was negatively correlated with uCa but positively associated with speed of sound after adjustment. No association was found between uCa and QUS parameters after adjustment, but when additionally adjusting for uNa, uCa was negatively associated with SI. Our findings suggest that urinary mineral concentrations are associated with calcaneal QUS parameters and may therefore implicate bone properties. These findings should be confirmed in longitudinal studies that include the food intake and repeated measurement of urinary mineral concentrations to better estimate usual intake and minimize bias.

The Distribution of Elements in 48 Canine Compact Bone Types Using Handheld X-Ray Fluorescence.

A major question when we talk about the elements in the bone is whether all bones contain the same elements. To answer this question, this study was designed for determination of the elemental levels in 48 various canine compact bones using handheld X-ray fluorescence technique. From a total of 26 elements that could be detected, only 13 elements were found in all 48 bones. The sternum and os penis were significantly different from the other bones in that they contained the highest number of elements. The ratio of Ca and P was significantly different when comparing certain bones: there was a higher Ca/P ratio in the patella (right), calcaneus (right and left), and sternum compared with a lower ratio in the radius (left), rib (left), phalanx (left forelimb), and carpus (left). These results are the first to demonstrate that different types of bones have different elemental profiles, even for major elements such as Ca and P. Moreover, the Ca/P ratio was also different between bone types. This data is important for the selection of bones appropriate to the element studied. In addition, the results proved that the elements were not equally distributed in every bone in the body.

Más de 10 años de seguimiento de la técnica de calcáneo stop / More than 10 years of follow up of the stop screw technique

Introducción. El pie plano valgo flexible infantil no requiere tratamiento en la mayoría de los casos. Cuando son sintomáticos se tratan de manera ortopédica y si no se consigue mejoría se procede a la cirugía. Material y métodos. Se describen los casos operados en el Hospital 12 de Octubre con la técnica de calcáneo stop entre los años 1995 y 2002. Se valora también cómo están actualmente estos pacientes. Hemos medido 6 ángulos en la radiografía antes de la cirugía y en la radiografía posterior a esta, y se comparan los ángulos para saber si la corrección conseguida es estadísticamente significativa. En el momento actual se valora una muestra más reducida de pacientes con las mismas mediciones radiológicas y escalas de valoración clínica: de Lickert, y de Smith y Millar. Las últimas radiografías son valoradas por 2 radiólogos para ver si existe artrosis subastragalina. Resultados. A corto plazo se observan diferencias estadísticamente significativas en todos los ángulos. Comparando los ángulos poscirugía con los actuales se concluye que no hay diferencias, excepto en el ángulo de Giannestras, que ha empeorado de manera estadísticamente significativa. Los resultados clínicos y la satisfacción de los pacientes es buena. En las radiografías actuales hay artrosis subastragalina muy incipiente en el 68,5% de los pacientes. Conclusiones. El calcáneo stop es una técnica barata, sencilla y eficaz para corregir el pie plano flexible infantil sintomático y que no haya respondido a medidas conservadoras. La técnica corrige el pie a corto plazo y esta corrección se mantiene en el tiempo (AU)

Introduction. Infantile flexible flatfoot does not require treatment in most cases. Symptomatic flexible flat feet are treated orthopaedically and surgery is only indicated when orthosis fails. Material and methods. Cases who underwent surgical treatment with the stop screw technique at the 12 de Octubre Hospital between 1995 and 2002 are reported. Patient progress is also analysed. Six angles are measured on the x-ray prior to surgery and those same x-ray angles are measured again before material extraction. They are then compared to see if the correction achieved is statistically significant. A more reduced sample is currently being assessed with the same radiological measurements and two clinical assessment scales: Lickert, and Smith and Millar. The latest x-rays are analysed by two radiologists to determine if there is subtalar arthrosis. Results. In the short term, statistically significant differences are observed in all angles. The comparison between the post-surgery angles and the current angles does not show differences, except for the Giannestras angle, which has statistically significantly worsened. Clinical results and patient satisfaction is good. Incipient subtalar arthrosis is present in 68.5% of current patient x-rays. Conclusions. Stop screw method is a cheap, simple and effective technique to correct symptomatic flexible flatfoot that has not improved with conservative treatment. This technique provides short-term foot correction which can be maintained over time (AU)

Bone Marrow Lipid Profiles from Peripheral Skeleton as Potential Biomarkers for Osteoporosis: A 1H-MR Spectroscopy Study.

RATIONALE AND OBJECTIVES: To characterize the lipidic profile of bone marrow in the calcaneus and femoral neck of healthy, osteopenic, and osteoporotic women, by using magnetic resonance spectroscopy (MRS) at 3T. The final goal was to identify specific metabolites with the potential ability to discriminate between healthy, osteopenic, and osteoporotic subjects. MATERIALS AND METHODS: Sixty-two and thirty three postmenopausal women recruited to investigate calcaneus and femoral neck, respectively, underwent a bone mineral density (BMD) measurement to be classified as healthy subjects (n = 22), osteopenic (n = 45), or osteoporotic (n = 28) patients. MRS spectra were used to quantify and compare bone marrow fat resonances between the three BMD groups. Between-group differences were tested using a Welch analysis of variance. Multiple comparisons were made with the Games-Howell correction. Relationships between pairs of variables were assessed with linear correlation analysis. Reproducibility analysis was performed for all the lipid resonances in both sites. RESULTS: The reproducibility was satisfactory. In femoral neck, methylene (L13), glycerol (L41, L43), and total lipid resonances were significantly lower in healthy as compared to osteoporotic subjects. On the other hand, in calcaneus, L13/glycerol significantly discriminated between osteopenic and osteoporotic subjects whereas L13/(unsaturated lipid) discriminated between healthy and osteopenic group. However, the reproducibility of both unsaturated lipid and glycerol resonances were less optimal. CONCLUSIONS: MRS of bone marrow lipid profiles from peripheral skeletal sites may be a promising tool for screening of large population to identify individuals with or at risk for developing osteoporosis. Moreover, it provides information about the metabolic changes occurring in bone marrow with the development of osteoporosis, which are skeletal site dependent.

Effect of minodronate on the speed of sound of the calcaneus in postmenopausal women with an increased risk of fractures: A clinical practice-based observational study.

BACKGROUND: We previously reported that alendronate and risedronate reduce the urinary levels of cross-linked N-terminal telopeptides of type I collagen (NTX) by 44.9% and 34.7%, respectively, at 3 months after the start of treatment, and increase the speed of sound (SOS) of the calcaneus by 0.6% and 0.65%, respectively, at 12 months after the start of treatment in postmenopausal women with osteoporosis. The aim of the present clinical practice-based observational study was to examine the effect of treatment with minodronate for 12 months on the SOS of the calcaneus and on bone turnover markers in postmenopausal women with an increased risk of fractures. METHODS: Forty-two postmenopausal women with osteoporosis or osteopenia with a clinical risk factor for fractures who had been treated with minodronate for > 12 months were enrolled in the study. The SOS and bone turnover markers were monitored during treatment with minodronate for 12 months. RESULTS: Compared to their baseline values, the urinary levels of NTX at 3 months and the serum levels of alkaline phosphatase at 12 months were significantly decreased at 47.5% and 25.8%, respectively. At 12 months, the SOS increased modestly, but significantly, by 0.47%, compared to the baseline value. CONCLUSION: The present study confirmed that minodronate suppressed bone turnover and modestly increased the SOS of the calcaneus in postmenopausal women with an increased risk of fractures.

COMPARISON OF T-SCORE VALUES OBTAINED BY ULTRASOUND OSTEODENSITOMETRY OF CALCANEUS AND BY DUAL-ENERGY X-RAY ABSORPTIOMETRY SCAN.

INTRODUCTION: Osteoporosis is the most frequent metabolic disease of bones. Early detection of pathological loss of bone mineral density represents the first step in prevention, treatment and rehabilitation of osteoporosis. This study was aimed at establishing the correlation of T-score values obtained by ultrasound osteodensitometry of calcaneus with dual-energy x-ray absorptiometry scan. MATERIAL AND METHODS: The study was conducted on the sample of 569 female patients from September 13,2010 to March 10, 2011. Measurement was made with ultrasound osteodensitometry of ACHILLES make. Quantitative ultrasound method revealed that 77 female patients had a lower value of T-score (osteopenia with risk factors or osteoporosis) and they were referred to T-score measurement with dual-energy x-ray absorptiometry scan. Dual-energy x-ray absorptiometry scanning was performed using LUNAR DPX scanner and 49 female patients were examined. RESULTS: It was concluded that there was no statistically significant difference between T-score values obtained by quantitative ultrasound and dual-energy x-ray absorptiometry scanning. CONCLUSION: According to this study, it is necessary to provide a greater number of scanners for ultrasound osteodensitometry of calcaneus in order to secure prevention and to refer the patients to further diagnosing on time.

Exhaustive exercise with different rest periods changes the collagen content and MMP-2 activation on the calcaneal tendon.

Tendons adapt to different mechanical stimuli through a remodeling process involving metalloproteinases (MMPs) and collagen synthesis. The purpose of this study was to investigate the activities of MMP-2 and MMP-9 and the collagen content in tendons after exhaustive acute exercise sessions over the course of 1, 3, or 6 days, with 1-hr or 3-hr rest periods between each session. Wistar rats were grouped into control (C), trained with 1-hr (groups 1d1h, 3d1h, and 6d1h) and trained with 3-hr (groups 1d3h, 3d3h and 6d3h) groups with rest periods between the treadmill running sessions, for 1, 3, and 6 days. The analysis of MMP-2 showed a larger presence of the latent isoform in the 1d3h group and a larger presence of the active isoform in the 6d3h group compared to the control. No differences were detected for MMP-9. A lower concentration of hydroxyproline was found in the 6d3h group compared to the 6d1h group. Sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis showed more prominent collagen bands in the 6d3h group, which was confirmed by Western blotting for collagen type I. A higher concentration of glycosaminoglycans was observed in the 3d3h group compared to the 3d1h group, and the 6d3h group presented the highest value for non-collagenous proteins compared to other groups. In conclusion, different rest periods between exercise sessions had different effects on the composition of the calcaneal tendon because a greater activation of MMP-2 and a reduction of total collagen were observed on day 6 of exercise with 3-hr rest periods compared to 1-hr rest periods.

Mechanical and morphological aspects of the calcaneal tendon of mdx mice at 21 days of age.

A relationship between compromised muscles and other tissues has been demonstrated in mdx mouse, an animal model studied for understanding of Duchenne muscular dystrophy. The hypothesis is that changes in the calcaneal tendon of mdx mice occur previous to the onset of rigorous and most marked episodes of muscle degeneration, which start suddenly after 21 days of life. Thus, this study aimed to identify possible alterations in the calcaneal tendon of mdx mouse at 21 days of age. Control and mdx tendons were submitted to mechanical tensile testing, quantification of hydroxyproline, and staining with toluidine blue and picrosirius red. Hydroxyproline content was similar between mdx and control groups. The control tendon presented higher mechanical strength (load, stress, and elastic modulus) and its morphological analysis showed a larger number of round fibroblasts, nuclei with well-decondensed chromatin, and slightly metachromatic well-stained cytoplasmic material, different from that observed in mdx tendons. The results suggest that the absence of dystrophin in mdx mouse can provoke directly or indirectly alterations in the mechanical properties and morphology of the calcaneal tendon.

Active vitamin D (1,25-dihydroxyvitamin D) and bone health in middle-aged and elderly men: the European Male Aging Study (EMAS).

CONTEXT: There is little information on the potential impact of serum 1,25-dihydroxyvitamin D [1,25(OH)2D] on bone health including turnover. OBJECTIVE: The objective of the study was to determine the influence of 1,25(OH)2D and 25-hydroxyvitamin D [25(OH)D] on bone health in middle-aged and older European men. DESIGN, SETTING, AND PARTICIPANTS: Men aged 40-79 years were recruited from population registers in 8 European centers. Subjects completed questionnaires that included questions concerning lifestyle and were invited to attend for quantitative ultrasound (QUS) of the heel, assessment of height and weight, and a fasting blood sample from which 1,25(OH)2D, 25(OH)D, and PTH were measured. 1,25(OH)2D was measured using liquid chromatography tandem mass spectrometry. Bone markers serum N-terminal propeptide of type 1 procollagen (P1NP) and crosslinks (ß-cTX) were also measured. Dual-energy x-ray absorptiometry (DXA) of the hip and lumbar spine was performed in 2 centers. MAIN OUTCOME MEASURE(S): QUS of the heel, bone markers P1NP and ß-cTX, and DXA of the hip and lumbar spine were measured. RESULTS: A total of 2783 men, mean age 60.0 years (SD 11.0) were included in the analysis. After adjustment for age and center, 1,25(OH)2D was positively associated with 25(OH)D but not with PTH. 25(OH)D was negatively associated with PTH. After adjustment for age, center, height, weight, lifestyle factors, and season, 1,25(OH)2D was associated negatively with QUS and DXA parameters and associated positively with ß-cTX. 1,25(OH)2D was not correlated with P1NP. 25(OH)D was positively associated with the QUS and DXA parameters but not related to either bone turnover marker. Subjects with both high 1,25(OH)2D (upper tertile) and low 25(OH)D (lower tertile) had the lowest QUS and DXA parameters and the highest ß-cTX levels. CONCLUSIONS: Serum 1,25(OH)2D is associated with higher bone turnover and poorer bone health despite being positively related to 25(OH)D. A combination of high 1,25(OH)2D and low 25(OH)D is associated with the poorest bone health.

Relationship between self-reported high-heeled shoe use and bone mineral density using quantitative ultrasound at a community health fair.

This is the first known study to examine the relationship between high-heel use and bone mineral density (BMD). Because women are disproportionately affected by osteoporosis, it is important to identify possible modifiable behaviors of women that may adversely affect bone health. Many studies have shown changes in body mechanics when wearing high-heeled shoes in comparison to normal gait. Because the composition of bone changes according to mechanical load and muscle activity, this study investigates whether wearing high heels may alter BMD. Two hundred and twenty-one participants at a community health fair in Lansing, Michigan, were surveyed on high-heel use and bone health risk (gender, thin/small frame, fair skin, family history of fracture, smoking history, walking, dairy consumption, and early menopause or oopherectomy at <45 years old). Quantitative ultrasound (QUS) of the heel by Hologic's Sahara Sonometer was used to measure BMD. The mean age was 45.2 (SD 13.7) years, and the majority of participants were female (208, 94 %). A significant difference between mean BMD and high-heel use was not found. Independent correlations existed between fair skinned/sunburn easily and BMD, r(212) = -0.14, p = 0.038, as well as history of smoking and BMD, r(212) = -0.14, p = 0.042. Bone health risk score was strongly correlated with heel use binary variable "yes/no," r(210) = 0.21, p = 0.003. Our study suggests that wearing high-heeled shoes does not lead to appreciable differences in BMD among community health fair participants as assessed by QUS.

Nonlinearity in the relationship between bone lead concentrations and CBLI for lead smelter employees.

494 smelter employees from New Brunswick participated in a bone lead survey conducted by McMaster University in 2008, using the four element "clover-leaf" geometry germanium detector system. The employees were measured at two different bone sites, tibia and calcaneus, each measurement lasting 30 minutes. Scattered photons, including Pb X-rays, were collected by the germanium detectors located behind the ¹°9Cd source. A strong positive correlation was observed between tibia and calcaneus lead concentrations. Having been provided with blood lead levels, a cumulative blood lead index (CBLI) was generated. The employees were classified into four groups based on their date of hire, and their CBLI levels were compared to their tibia and calcaneus lead concentrations in the different groups. The slopes of bone Pb versus CBLI varied amongst groups, with those hired earliest showing the steepest slopes. This could be taken to imply a non-linearity in the uptake of Pb by bone from blood. In this paper, the association of the bone lead concentrations versus CBLI has been expressed by a polynomial function for the whole group of employees.

Relationship between markers of body fat and calcaneal bone stiffness differs between preschool and primary school children: results from the IDEFICS baseline survey.

The aim of this study was to investigate the relationship between markers of body fat and bone status assessed as calcaneal bone stiffness in a large sample of European healthy pre- and primary school children. Participants were 7,447 children from the IDEFICS study (spread over eight different European countries), age 6.1 ± 1.8 years (range 2.1-9.9), 50.5 % boys. Anthropometric measurements (weight, height, bioelectrical impedance, waist and hip circumference, and tricipital and subscapular skinfold thickness) as well as quantitative ultrasonographic measurements to determine calcaneal stiffness index (SI) were performed. Partial correlation analysis, linear regression analysis, and ANCOVA were stratified by sex and age group: preschool boys (n = 1,699) and girls (n = 1,599) and primary school boys (n = 2,062) and girls (n = 2,087). In the overall study population, the average calcaneal SI was equal to 80.2 ± 14.0, ranging 42.4-153. The results showed that preschool children with higher body fat had lower calcaneal SI (significant correlation coefficients between -0.05 and -0.20), while primary school children with higher body fat had higher calcaneal SI (significant correlation coefficients between 0.05 and 0.13). After adjusting for fat-free mass, both preschool and primary school children showed an inverse relationship between body fat and calcaneal stiffness. To conclude, body fat is negatively associated with calcaneal bone stiffness in children after adjustment for fat-free mass. Fat-free mass may confound the association in primary school children but not in preschool children. Muscle mass may therefore be an important determinant of bone stiffness.