Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 516
Filtrar
Más filtros

Tipo del documento
Intervalo de año de publicación
1.
Osteoporos Int ; 26(10): 2509-19, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26021761

RESUMEN

UNLABELLED: In 27 centres across Europe, the prevalence of deforming spinal Scheuermann's disease in age-stratified population-based samples of over 10,000 men and women aged 50+ averaged 8% in each sex, but was highly variable between centres. Low DXA BMD was un-associated with Scheuermann's, helping the differential diagnosis from osteoporosis. INTRODUCTION: This study aims to assess the prevalence of Scheuermann's disease of the spine across Europe in men and women over 50 years of age, to quantitate its association with bone mineral density (BMD) and to assess its role as a confounder for the radiographic diagnosis of osteoporotic fracture. METHODS: In 27 centres participating in the population-based European Vertebral Osteoporosis Study (EVOS), standardised lateral radiographs of the lumbar and of the thoracic spine from T4 to L4 were assessed in all those of adequate quality. The presence of Scheuermann's disease, a confounder for prevalent fracture in later life, was defined by the presence of at least one Schmorl's node or irregular endplate together with kyphosis (sagittal Cobb angle >40° between T4 and T12) or a wedged-shaped vertebral body. Alternatively, the (rare) Edgren-Vaino sign was taken as diagnostic. The 6-point-per-vertebral-body (13 vertebrae) method was used to assess osteoporotic vertebral shape and fracture caseness. DXA BMD of the L2-L4 and femoral neck regions was measured in subsets. We also assessed the presence of Scheuermann's by alternative published algorithms when these used the radiographic signs we assessed. RESULTS: Vertebral radiographic images from 4486 men and 5655 women passed all quality checks. Prevalence of Scheuermann's varied considerably between centres, and based on random effect modelling, the overall European prevalence using our method was 8% with no significant difference between sexes. The highest prevalences were seen in Germany, Sweden, the UK and France and low prevalences were seen in Hungary, Poland and Slovakia. Centre-level prevalences in men and women were highly correlated. Scheuermann's was not associated with BMD of the spine or hip. CONCLUSIONS: Since most of the variation in population impact of Scheuermann's was unaccounted for by the radiological and anthropometric data, the search for new genetic and environmental determinants of this disease is encouraged.


Asunto(s)
Enfermedad de Scheuermann/epidemiología , Anciano , Estatura/fisiología , Densidad Ósea/fisiología , Europa (Continente)/epidemiología , Femenino , Cuello Femoral/diagnóstico por imagen , Cuello Femoral/fisiopatología , Humanos , Vértebras Lumbares/diagnóstico por imagen , Vértebras Lumbares/fisiopatología , Masculino , Persona de Mediana Edad , Prevalencia , Radiografía , Reproducibilidad de los Resultados , Enfermedad de Scheuermann/diagnóstico por imagen , Enfermedad de Scheuermann/fisiopatología
2.
Osteoporos Int ; 24(8): 2345-52, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23612793

RESUMEN

UNLABELLED: This observational study showed that after 2 years, both risedronate and alendronate lowered the risk of hip and nonvertebral fractures compared with patients filling in a single bisphosphonate prescription. INTRODUCTION: Post hoc analyses of the placebo-controlled trials suggested earlier effects for risedronate (6-12 months) than for alendronate (18-24 months). The present study extends our 1-year observational data that confirmed an earlier fracture reduction with risedronate and evaluated the absolute and relative effectiveness of alendronate and risedronate in clinical practice over 2 years. METHODS: We observed three cohorts of women aged 65 years and older who initiated once-a-week dosing of bisphosphonate therapy; (1) patients adherent to alendronate (n = 21,615), (2) patients adherent to risedronate (n = 12,215), or (3) patients filling only a single bisphosphonate prescription (n = 5,390) as a referent population. Proportional hazard modeling compared the incidence of hip and nonvertebral fractures among the cohorts over 2 years after the initial prescription. RESULTS: In this cohort, we previously showed at 12 months a significant reduction of hip and nonvertebral fractures with risedronate but not with alendronate. At the end of 2 years, the cumulative incidence of hip fractures in the referent cohort was 1.9 %, and incidence of nonvertebral fractures was 6.3 %. Relative to the referent, 6 months after initiating therapy and continuing through 2 years, both risedronate and alendronate cohorts had approximately a 45 % lower incidence of hip fractures and a 30 % lower incidence of nonvertebral fractures. CONCLUSION: These observations suggest that both risedronate and alendronate are effective at reducing the risk of hip and nonvertebral fracture after 2 years of treatment and support the post hoc analyses of placebo-controlled trials indicating an earlier effect of risedronate.


Asunto(s)
Alendronato/uso terapéutico , Conservadores de la Densidad Ósea/uso terapéutico , Ácido Etidrónico/análogos & derivados , Fracturas Osteoporóticas/prevención & control , Anciano , Alendronato/administración & dosificación , Conservadores de la Densidad Ósea/administración & dosificación , Difosfonatos/administración & dosificación , Difosfonatos/uso terapéutico , Esquema de Medicación , Ácido Etidrónico/administración & dosificación , Ácido Etidrónico/uso terapéutico , Femenino , Fracturas de Cadera/epidemiología , Fracturas de Cadera/etiología , Fracturas de Cadera/prevención & control , Humanos , Incidencia , Cumplimiento de la Medicación/estadística & datos numéricos , Osteoporosis Posmenopáusica/complicaciones , Osteoporosis Posmenopáusica/tratamiento farmacológico , Osteoporosis Posmenopáusica/epidemiología , Fracturas Osteoporóticas/epidemiología , Fracturas Osteoporóticas/etiología , Ácido Risedrónico , Resultado del Tratamiento , Estados Unidos/epidemiología
3.
Osteoporos Int ; 24(1): 293-9, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22752050

RESUMEN

UNLABELLED: This study showed that risedronate 150-mg once a month provides similar efficacy and safety at 2 years compared with risedronate 5-mg daily for the treatment of postmenopausal osteoporosis. This adds to the range of risedronate dosing options and provides an alternative for patients who prefer once-a-month dosing. INTRODUCTION: Risedronate is effective in the treatment of postmenopausal osteoporosis in oral daily, weekly, or on two consecutive days per month doses. This 2-year randomized, double-blind, multicenter study assesses the efficacy and safety of a single risedronate 150-mg once-a-month oral dose compared with the 5-mg daily regimen. METHODS: Women with postmenopausal osteoporosis were randomly assigned to receive risedronate 5-mg daily (n = 642) or 150-mg once a month (n = 650) for 2 years. Bone mineral density (BMD), bone turnover markers, new vertebral fractures, and adverse events were evaluated. The primary efficacy endpoint was the mean percent change from baseline in lumbar spine BMD after 1 year. RESULTS: Four hundred ninety-eight subjects in the daily group (77.6 %) and 513 subjects in the once-a-month group (78.9 %) completed the study. After 24 months, the mean percent change in lumbar spine BMD was 3.9 % (95 % confidence interval [CI], 3.43 to 4.42 %) and 4.2 % (95 % CI, 3.68 to 4.65 %) in the daily and once-a-month groups, respectively. The once-a-month regimen was determined to be non-inferior to the daily regimen. The mean percent changes in BMD at the hip were similar in both dose groups, as were changes in biochemical markers of bone turnover. The incidence of adverse events, adverse events leading to withdrawal, and upper gastrointestinal tract adverse events were similar in the two treatment groups. CONCLUSIONS: After 2 years, treatment with risedronate 150-mg once a month provided similar efficacy and tolerability to daily dosing and provides an alternative for patients who prefer once-a-month oral dosing.


Asunto(s)
Conservadores de la Densidad Ósea/administración & dosificación , Ácido Etidrónico/análogos & derivados , Osteoporosis Posmenopáusica/tratamiento farmacológico , Administración Oral , Anciano , Biomarcadores/sangre , Densidad Ósea/efectos de los fármacos , Conservadores de la Densidad Ósea/efectos adversos , Conservadores de la Densidad Ósea/uso terapéutico , Método Doble Ciego , Esquema de Medicación , Ácido Etidrónico/administración & dosificación , Ácido Etidrónico/efectos adversos , Ácido Etidrónico/uso terapéutico , Femenino , Fémur/fisiopatología , Humanos , Vértebras Lumbares/fisiopatología , Persona de Mediana Edad , Osteoporosis Posmenopáusica/fisiopatología , Ácido Risedrónico , Resultado del Tratamiento
4.
Osteoporos Int ; 24(1): 311-20, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22402673

RESUMEN

UNLABELLED: We have examined the effect of oral monthly ibandronate on distal radius and tibia microarchitecture with high-resolution peripheral quantitative tomography compared with placebo, in women with osteopenia, and found that ibandronate did not significantly affect trabecular bone but improved cortical density and thickness at the tibia. METHODS: We have examined the effect of ibandronate on bone microarchitecture with peripheral high-resolution quantitative computed tomography (HR-pQCT) in a randomized placebo-controlled trial among 148 women with osteopenia. Patients received either oral 150 mg monthly ibandronate or placebo over 24 months. Bone microarchitecture was assessed at baseline, 6, 12, and 24 months, using HR-pQCT at the distal radius and tibia; areal bone mineral density (aBMD) was measured with DXA at the spine, hip, and radius. RESULTS: At 12 months, there was no significant difference in trabecular bone volume at the radius (the primary end point) between women on ibandronate (10.8 ± 2.5%) and placebo (10.5 ± 2.9%), p = 0.25. There was no significant difference in other radius trabecular and cortical microarchitecture parameters at 12 and 24 months. In contrast, at the tibia, cortical vBMD in the ibandronate group was significantly greater than in the placebo group at 6, 12, and 24 months, with better cortical thickness at 6, 12, and 24 months. With ibandronate, aBMD was significantly increased at the hip and spine at 12 and 24 months but at the radius was significantly superior to placebo only at 24 months. Most of the adverse events related to ibandronate were expected with bisphosphonate use, and none of them were serious. CONCLUSION: We conclude that 12 months of treatment with ibandronate in women with osteopenia did not affect trabecular bone microarchitecture, but improved cortical vBMD at the tibia at 12 and 24 months, and preserved cortical thickness at the tibia.


Asunto(s)
Conservadores de la Densidad Ósea/administración & dosificación , Enfermedades Óseas Metabólicas/tratamiento farmacológico , Difosfonatos/administración & dosificación , Administración Oral , Anciano , Densidad Ósea/efectos de los fármacos , Conservadores de la Densidad Ósea/efectos adversos , Conservadores de la Densidad Ósea/uso terapéutico , Enfermedades Óseas Metabólicas/patología , Enfermedades Óseas Metabólicas/fisiopatología , Difosfonatos/efectos adversos , Difosfonatos/uso terapéutico , Método Doble Ciego , Esquema de Medicación , Femenino , Humanos , Ácido Ibandrónico , Persona de Mediana Edad , Radio (Anatomía)/patología , Radio (Anatomía)/fisiopatología , Tibia/patología , Tibia/fisiopatología , Tomografía Computarizada por Rayos X
5.
Arch Pediatr ; 19(8): 786-93, 2012 Aug.
Artículo en Francés | MEDLINE | ID: mdl-22743171

RESUMEN

OBJECTIVES: Continuity of care is a major challenge for young people living with HIV, especially when transitioning from pediatric to adult care. A qualitative study was conducted in an attempt to explore and describe the transitions resulting from this change of care and to identify factors influencing this process. PATIENTS AND METHODS: Seven young adults, HIV-infected since childhood, with a median age of 25 years, with more than 2 years of experience since transitioning to adult care, participated in this qualitative research. Data were collected through semi-structured interviews. RESULTS: Becoming an adult has depended upon a double change in perception: leaving the cocoon of the pediatric ward made them feel more adult, but entering the adult universe where the disease is more visible and the environment more "cold" and "unfamiliar" made them feel more vulnerable. This "clash of worlds" creates a transformation leading to adulthood, where a relation based on mutual trust remains fundamental for the continuity of care and for pursuing the youth's personal development in the social and affective spheres. CONCLUSION: Self-construction on various levels (identity, social, affective) while maintaining regular medical care is the challenge of youth transitioning to adult care. A specific nurse-based consultation could be a useful tool for helping young people through this difficult process.


Asunto(s)
Infecciones por VIH/psicología , Transición a la Atención de Adultos , Adolescente , Desarrollo del Adolescente , Adulto , Femenino , Infecciones por VIH/terapia , Humanos , Masculino , Autonomía Personal , Estigma Social , Adulto Joven
6.
Osteoporos Int ; 23(9): 2321-7, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22179418

RESUMEN

UNLABELLED: The incidence of hip fracture, death and the estimated incidence of major osteoporotic fracture in France were used to determine the lifetime and 10-year probability of fracture and incorporated into a probability model (FRAX®) calibrated to the French population. INTRODUCTION: Fracture probabilities in the French population have not been determined. Our aim was to determine the incidence of hip fracture in France and the estimated 10-year probabilities of hip and major osteoporotic fractures. METHODS: The study population included adults over 50 years living in France in 2004. Incident hip fracture cases were identified from the French PMSI database. Incidence of the other major osteoporotic fractures was imputed from the relationship between hip fracture incidence and other major fracture in Sweden. These data were used to calculate population-based fracture probabilities according to age and BMD using cutoff values for femoral neck T-scores from the NHANES III data in Caucasian women. The probability model (FRAX®) calibrated to the French population was used to compute individual fracture probabilities according to specific clinical risk factors. RESULTS: We identified 15,434 men and 51,469 women with an incident hip fracture. The remaining lifetime probability of hip fracture at 50 years was approximately 10 and 30% respectively. With a femoral neck T-score of -2 SD, one in two women and one in five men would sustain a major osteoporotic fracture in their lifetime. The 10-year probability of other major osteoporotic fractures increased with declining T-score and increasing age. Low body mass index and other clinical risk factors had an independent effect on fracture probability whether or not BMD was included in the FRAX® model. CONCLUSION: This analysis provides detailed estimation on the risk of fracture in the French population and may help to define therapeutic guidelines.


Asunto(s)
Fracturas de Cadera/epidemiología , Fracturas Osteoporóticas/epidemiología , Anciano , Femenino , Francia/epidemiología , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Medición de Riesgo/métodos , Factores de Riesgo , Factores de Tiempo
7.
Comput Med Imaging Graph ; 35(6): 427-37, 2011 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-21621977

RESUMEN

Three dimensional (3D) visualization of anatomy plays an important role in image guided orthopedic surgery and ultimately motivates minimally invasive procedures. However, direct 3D imaging modalities such as Computed Tomography (CT) are restricted to a minority of complex orthopedic procedures. Thus the diagnostics and planning of many interventions still rely on two dimensional (2D) radiographic images, where the surgeon has to mentally visualize the anatomy of interest. The purpose of this paper is to apply and validate a bi-planar 3D reconstruction methodology driven by prominent bony anatomy edges and contours identified on orthogonal radiographs. The results obtained through the proposed methodology are benchmarked against 3D CT scan data to assess the accuracy of reconstruction. The human femur has been used as the anatomy of interest throughout the paper. The novelty of this methodology is that it not only involves the outer contours of the bony anatomy in the reconstruction but also several key interior edges identifiable on radiographic images. Hence, this framework is not simply limited to long bones, but is generally applicable to a multitude of other bony anatomies as illustrated in the results section.


Asunto(s)
Regeneración Ósea , Diagnóstico por Imagen , Fémur/diagnóstico por imagen , Imagenología Tridimensional , Fémur/anatomía & histología , Fémur/lesiones , Fémur/cirugía , Humanos , Ortopedia , Tomografía Computarizada por Rayos X
8.
Eur J Endocrinol ; 165(1): 151-9, 2011 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-21490123

RESUMEN

UNLABELLED: OBJECTVIE: In the elderly, vitamin D deficit, low calcium intake, and impaired bone microarchitecture are associated with higher risk of hip fracture. We assessed the association of bone microarchitecture with calcium intake and serum concentrations of 25-hydroxycholecalciferol (25OHD) and parathyroid hormone (PTH) in men. DESIGN: Cross-sectional analysis was performed in 1064 men aged 20-87 years not taking vitamin D or calcium supplements. METHODS: Daily calcium intake was assessed using a food frequency questionnaire. Bone microarchitecture was assessed at distal radius and tibia by high-resolution peripheral quantitative computed tomography. We measured serum and urinary levels of biochemical bone turnover markers (BTMs). Statistical models were adjusted for age, weight, height, and glomerular filtration rate. RESULTS: In 500 men aged <65 years, lower 25OHD levels and low calcium intake were associated with lower trabecular volumetric bone mineral density (Dtrab) at the distal tibia, due to lower trabecular number (Tb.N). Low calcium intake was associated with lower cortical thickness (Ct.Th). Higher PTH level was associated with higher BTM levels. In 563 men aged ≥65 years, the highest PTH quartile was associated with lower Ct.Th (tibia), lower Dtrab (both sites), and lower Tb.N (radius) compared with the lowest quartile. Low calcium intake was associated with lower Tb.N and more heterogenous trabecular distribution. BTM positively correlated with the PTH concentration. CONCLUSION: In older men, elevated PTH concentration is associated with high bone turnover, poor trabecular microarchitecture (radius and tibia), and, at the distal tibia, lower Ct.Th. Low calcium intake is associated with lower Tb.N and more heterogenous trabecular distribution.


Asunto(s)
Densidad Ósea , Calcio de la Dieta/administración & dosificación , Hormona Paratiroidea/sangre , Radio (Anatomía)/diagnóstico por imagen , Tibia/diagnóstico por imagen , Adulto , Anciano , Anciano de 80 o más Años , Calcifediol/sangre , Estudios de Cohortes , Fracturas de Cadera/prevención & control , Humanos , Masculino , Persona de Mediana Edad , Osteocalcina/sangre , Estudios Prospectivos , Tomografía Computarizada por Rayos X
9.
Osteoporos Int ; 22(6): 1755-64, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20838767

RESUMEN

UNLABELLED: Identification of older men at high risk of peripheral fracture can be improved by assessing prevalent fractures (men aged ≤ 65), history of falls (men aged >65), bone width, and aortic calcifications. INTRODUCTION: Low bone mineral density (BMD) identifies 20% of men who sustain osteoporotic fracture. We studied (1) if the assessment of bone width, aortic calcifications, prevalent falls and fractures improves identification of men at high risk of fracture and (2) if the predictive value of these parameters varies with age. METHODS: Among 781 men aged 50 and over, 61 men sustained 66 low-trauma peripheral fractures during 10 years. History of falls and prevalent fractures was assessed by questionnaire. BMD and bone with were measured by dual X-ray absorptiometry. Abdominal aortic calcifications were assessed on the lateral radiographs of the lumbar spine. RESULTS: Low BMD, low bone width, extended aortic calcifications, prevalent fractures (mainly multiple fractures) and frequent falls were all associated independently with higher risk of fracture. In men aged ≤ 65, prevalent fractures are associated with a significant increase in the risk of fracture (two- to threefold for one and four- to fivefold for multiple prevalent fractures). In men aged >65, history of falls is associated with a higher risk of fracture, e.g. frequent falls are associated with a sixfold increase in the risk of fracture. CONCLUSIONS: Men aged ≤ 65 with multiple prevalent fractures and frequent fallers aged >65 are at particularly high risk of peripheral fracture regardless of BMD.


Asunto(s)
Fracturas Osteoporóticas/etiología , Accidentes por Caídas/estadística & datos numéricos , Factores de Edad , Anciano , Anciano de 80 o más Años , Enfermedades de la Aorta/epidemiología , Índice de Masa Corporal , Densidad Ósea/fisiología , Métodos Epidemiológicos , Francia/epidemiología , Humanos , Masculino , Persona de Mediana Edad , Fracturas Osteoporóticas/epidemiología , Fracturas Osteoporóticas/fisiopatología , Recurrencia , Calcificación Vascular/epidemiología
10.
Osteoporos Int ; 22(1): 27-35, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-20358360

RESUMEN

UNLABELLED: We compared self-perception of fracture risk with actual risk among 60,393 postmenopausal women aged ≥55 years, using data from the Global Longitudinal Study of Osteoporosis in Women (GLOW). Most postmenopausal women with risk factors failed to appreciate their actual risk for fracture. Improved education about osteoporosis risk factors is needed. INTRODUCTION: This study seeks to compare self-perception of fracture risk with actual risk among postmenopausal women using data from GLOW. METHODS: GLOW is an international, observational, cohort study involving 723 physician practices in 17 sites in ten countries in Europe, North America, and Australia. Participants included 60,393 women ≥55 years attended by their physician during the previous 24 months. The sample was enriched so that two thirds were ≥65 years. Baseline surveys were mailed October 2006 to February 2008. Main outcome measures were self-perception of fracture risk in women with elevated risk vs women of the same age and frequency of risk factors for fragility fracture. RESULTS: In the overall study population, 19% (10,951/58,434) of women rated their risk of fracture as a little/much higher than that of women of the same age; 46% (27,138/58,434) said it was similar; 35% (20,345/58,434) believed it to be a little/much lower. Among women whose actual risk was increased based on the presence of any one of seven risk factors for fracture, the proportion who recognized their increased risk ranged from 19% for smokers to 39% for current users of glucocorticoid medication. Only 33% (4,185/12,612) of those with ≥2 risk factors perceived themselves as being at higher risk. Among women reporting a diagnosis of osteopenia or osteoporosis, only 25% and 43%, respectively, thought their risk was increased. CONCLUSION: In this international, observational study, most postmenopausal women with risk factors failed to appreciate their actual risk for fracture.


Asunto(s)
Conocimientos, Actitudes y Práctica en Salud , Osteoporosis Posmenopáusica/complicaciones , Fracturas Osteoporóticas/etiología , Anciano , Australia/epidemiología , Métodos Epidemiológicos , Europa (Continente)/epidemiología , Femenino , Humanos , Persona de Mediana Edad , América del Norte/epidemiología , Osteoporosis Posmenopáusica/diagnóstico , Osteoporosis Posmenopáusica/epidemiología , Osteoporosis Posmenopáusica/psicología , Fracturas Osteoporóticas/epidemiología , Fracturas Osteoporóticas/psicología
11.
Calcif Tissue Int ; 87(1): 52-9, 2010 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-20383765

RESUMEN

Low-intensity electrical stimulation (LIES) may counteract the effects of ovariectomy (OVX) on nitric oxide synthase (NOS) expression, osteocyte viability, bone structure, and microarchitecture in rats (Lirani-Galvão et al., Calcif Tissue Int 84:502-509, 2009). The aim of the present study was to investigate if these effects of LIES could be mediated by NO. We analyzed the effects of NO blockage (by L-NAME) in the response to LIES on osteocyte viability, bone structure, and microarchitecture in OVX rats. Sixty rats (200-220 g) were divided into six groups: sham, sham-L-NAME (6 mg/kg/day), OVX, OVX-L-NAME, OVX-LIES, and OVX-LIES-L-NAME. After 12 weeks, rats were killed and tibiae collected for histomorphometric analysis and immunohistochemical detection of endothelial NOS (eNOS), inducible NOS (iNOS), and osteocyte apoptosis (caspase-3 and TUNEL). In the presence of L-NAME, LIES did not counteract the OVX-induced effects on bone volume and trabecular number (as on OVX-LIES). L-NAME blocked the stimulatory effects of LIES on iNOS and eNOS expression of OVX rats. Both L-NAME and LIES decreased osteocyte apoptosis. Our results showed that in OVX rats L-NAME partially blocks the effects of LIES on bone structure, turnover, and expression of iNOS and eNOS, suggesting that NO may be a mediator of some positive effects of LIES on bone.


Asunto(s)
Óxido Nítrico/metabolismo , Animales , Apoptosis/efectos de los fármacos , Apoptosis/fisiología , Huesos/metabolismo , Caspasa 3 , Femenino , Etiquetado Corte-Fin in Situ , NG-Nitroarginina Metil Éster/farmacología , Óxido Nítrico Sintasa/metabolismo , Óxido Nítrico Sintasa de Tipo II , Óxido Nítrico Sintasa de Tipo III/metabolismo , Osteocitos/metabolismo , Osteocitos/fisiología , Ovariectomía , Ratas , Ratas Wistar
12.
Osteoporos Int ; 21(7): 1277-85, 2010 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-19802508

RESUMEN

UNLABELLED: Changes in bone mineral density and bone strength following treatment with zoledronic acid (ZOL) were measured by quantitative computed analysis (QCT) or dual-energy X-ray absorptiometry (DXA). ZOL treatment increased spine and hip BMD vs placebo, assessed by QCT and DXA. Changes in trabecular bone resulted in increased bone strength. INTRODUCTION: To investigate bone mineral density (BMD) changes in trabecular and cortical bone, estimated by quantitative computed analysis (QCT) or dual-energy X-ray absorptiometry (DXA), and whether zoledronic acid 5 mg (ZOL) affects bone strength. METHODS: In 233 women from a randomized, controlled trial of once-yearly ZOL, lumbar spine, total hip, femoral neck, and trochanter were assessed by DXA and QCT (baseline, Month 36). Mean percentage changes from baseline and between-treatment differences (ZOL vs placebo, t-test) were evaluated. RESULTS: Mean between-treatment differences for lumbar spine BMD were significant by DXA (7.0%, p < 0.01) and QCT (5.7%, p < 0.0001). Between-treatment differences were significant for trabecular spine (p = 0.0017) [non-parametric test], trabecular trochanter (10.7%, p < 0.0001), total hip (10.8%, p < 0.0001), and compressive strength indices at femoral neck (8.6%, p = 0.0001), and trochanter (14.1%, p < 0.0001). CONCLUSIONS: Once-yearly ZOL increased hip and spine BMD vs placebo, assessed by QCT vs DXA. Changes in trabecular bone resulted in increased indices of compressive strength.


Asunto(s)
Conservadores de la Densidad Ósea/administración & dosificación , Difosfonatos/administración & dosificación , Imidazoles/administración & dosificación , Osteoporosis Posmenopáusica/tratamiento farmacológico , Absorciometría de Fotón/métodos , Anciano , Anciano de 80 o más Años , Densidad Ósea/efectos de los fármacos , Conservadores de la Densidad Ósea/uso terapéutico , Fuerza Compresiva/efectos de los fármacos , Difosfonatos/uso terapéutico , Esquema de Medicación , Femenino , Cuello Femoral/efectos de los fármacos , Cuello Femoral/fisiopatología , Estudios de Seguimiento , Articulación de la Cadera/efectos de los fármacos , Articulación de la Cadera/fisiopatología , Humanos , Imidazoles/uso terapéutico , Vértebras Lumbares/efectos de los fármacos , Vértebras Lumbares/fisiopatología , Osteoporosis Posmenopáusica/fisiopatología , Tomografía Computarizada por Rayos X/métodos , Ácido Zoledrónico
13.
Bone ; 46(2): 342-7, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19836004

RESUMEN

UNLABELLED: It has been suggested that age-related deterioration in trabecular microarchitecture and changes in collagen cross-link concentrations may contribute to skeletal fragility. To further explore this hypothesis, we determined the relationships among trabecular bone volume fraction (BV/TV), microarchitecture, collagen cross-link content, and bone turnover in human vertebral trabecular bone. Trabecular bone specimens from L2 vertebrae were collected from 51 recently deceased donors (54-95 years of age; 20 men and 30 women). Trabecular bone volume and microarchitecture was assessed by microCT and bone formation, reflected by osteoid surface (OS/BS, %), was measured by 2D histomorphometry. Pyridinoline (PYD), deoxypyridinoline (DPD), pentosidine (PEN) and collagen content in the cancellous bone were analysed by high-performance liquid chromatography. Associations between variables were investigated by Pearson correlations and multiple regression models, which were constructed with BV/TV and collagen cross-links as explanatory variables and microarchitecture parameters as the dependent variables. RESULTS: Microarchitecture parameters were modestly to strongly correlated with BV/TV (r(2)=0.10-0.71). The amount of mature enzymatic PYD and DPD cross-links were not associated with the microarchitecture, either before or after adjustment for BV/TV. However, there was a positive correlation between PEN content and trabecular number (r=0.45, p=0.001) and connectivity density (r=0.40, p=0.004), and a negative correlation between PEN content and trabecular separation (r=-0.29, p=0.04). In the multiple regression models including BV/TV, age and PEN content was still significantly associated with several of the microarchitecture variables. In summary, this study suggests a link between trabecular microarchitecture and the collagen cross-link profile. As PEN reflects non-enzymatic glycation of collagen and generally increases with bone age, the association between PEN and trabecular architecture suggests that the preserved trabeculae may contain mainly old bone and have undergone little remodeling. Thus, vertebral fragility may not only be due to alterations in bone architecture but also to modification of collagen cross-link patterns thereby influencing bone's mechanical behavior.


Asunto(s)
Colágeno/metabolismo , Reactivos de Enlaces Cruzados/metabolismo , Columna Vertebral/patología , Anciano , Anciano de 80 o más Años , Envejecimiento/patología , Densidad Ósea , Femenino , Humanos , Masculino , Persona de Mediana Edad , Caracteres Sexuales , Propiedades de Superficie
14.
Osteoporos Int ; 21(4): 667-77, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19597910

RESUMEN

UNLABELLED: In postmenopausal osteoporotic women and up to 3 years of treatment with strontium ranelate, strontium was present only in recently deposited bone tissue resulting from formation activity during the period of treatment. Strontium was shown to be dose-dependently deposited into this newly formed bone with preservation of the mineralization. INTRODUCTION: Interactions between strontium (Sr) and bone mineral and its effects on mineralization were investigated in women treated with strontium ranelate. METHODS: Bone biopsies from osteoporotic women were obtained over 5-year strontium ranelate treatment from phases II and III studies. Bone samples obtained over 3-year treatment were investigated by X-ray microanalysis for bone Sr uptake and focal distribution, and by quantitative microradiography for degree of mineralization. On some samples, Sr distribution (X-ray cartography) was analyzed on whole sample surfaces and the percentage of bone surface containing Sr was calculated. Bone Sr content was chemically measured on whole samples. RESULTS: In treated women, Sr was exclusively present in bone formed during treatment; Sr deposition depended on the dose with higher focal content in new bone structural units than in old ones constantly devoid of Sr, even after 3-year treatment. A plateau in global bone Sr content was reached after 3 years of treatment. Cartography illustrated the extent of surfaces containing Sr, and formation activity during strontium ranelate treatment was higher in cancellous than in cortical bone. Mineralization was maintained during treatment. CONCLUSION: The quality of bone mineral was preserved after treatment with strontium ranelate, supporting the safety of this agent at the bone tissue level.


Asunto(s)
Conservadores de la Densidad Ósea/farmacocinética , Compuestos Organometálicos/farmacocinética , Osteoporosis Posmenopáusica/metabolismo , Tiofenos/farmacocinética , Anciano , Biopsia , Densidad Ósea/efectos de los fármacos , Conservadores de la Densidad Ósea/uso terapéutico , Huesos/metabolismo , Calcificación Fisiológica/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Microanálisis por Sonda Electrónica/métodos , Femenino , Humanos , Ilion/metabolismo , Ilion/patología , Microrradiografía/métodos , Persona de Mediana Edad , Compuestos Organometálicos/uso terapéutico , Osteoporosis Posmenopáusica/tratamiento farmacológico , Osteoporosis Posmenopáusica/patología , Osteoporosis Posmenopáusica/fisiopatología , Tiofenos/uso terapéutico
15.
Arch Pediatr ; 16(11): 1482-90, 2009 Nov.
Artículo en Francés | MEDLINE | ID: mdl-19766468

RESUMEN

Bone damage in the spectrum of chronic kidney disease - mineral and bone disorders (CKD-MBD) represents a daily challenge for pediatric nephrologists. A real measurement of bone mineral density (BMD) by Dual X-ray absorptiometry (DXA) is currently performed to evaluate bone mass in children. However this technique has some limitations. In 2000, the National Institute of Health (NIH) has defined new "quality" criteria for the diagnosis of osteoporosis in addition to a decreased bone mass. Bone strength actually integrates 2 issues: bone density and bone quality (i.e., micro architectural organization, bone turnover, mineralization and micro fractures). These "quality" criteria cannot be evaluated by DXA. Histomorphometry remains the gold standard to evaluate bone but it is rarely performed in clinical practice. New bone imaging techniques have thus been developed, leading to an improvement in bone assessment. They are particularly challenging in children, whose bones continually grow in size, shape and mass.


Asunto(s)
Trastorno Mineral y Óseo Asociado a la Enfermedad Renal Crónica/diagnóstico , Diagnóstico por Imagen , Procesamiento de Imagen Asistido por Computador , Imagenología Tridimensional , Fallo Renal Crónico/diagnóstico , Absorciometría de Fotón , Densidad Ósea/fisiología , Huesos/patología , Niño , Humanos , Imagen por Resonancia Magnética , Sensibilidad y Especificidad , Tomografía Computarizada por Rayos X , Ultrasonografía
16.
J Dent Res ; 88(10): 910-5, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19783798

RESUMEN

A primary cilium, a sensory organelle present in almost every vertebrate cell, is regularly described in odontoblasts, projecting from the surfaces of the cells. Based on the hypothesis that the primary cilium is crucial both for dentin formation and possibly in tooth pain transmission, we have investigated the expression and localization of the main cilium components and involvement of the OFD1 gene in tooth morphogenesis. Odontoblasts in vitro express tubulin, inversin, rootletin, OFD1, BBS4, BBS6, ALMS1, KIF3A, PC1, and PC2. In vivo, cilia are aligned parallel to the dentin walls, with the top part oriented toward the pulp core. Close relationships between cilium and nerve fibers are evidenced. Calcium channels are concentrated in the vicinity of the basal body. Analysis of these data suggests a putative role of cilia in sensing the microenvironment, probably related to dentin secretion. This hypothesis is enhanced by the huge defects observed on molars from Ofd1 knockout mice, showing undifferentiated dentin-forming cells.


Asunto(s)
Cilios/fisiología , Proteínas de Choque Térmico/fisiología , Diente Molar/crecimiento & desarrollo , Odontoblastos/fisiología , Odontogénesis/fisiología , Adolescente , Animales , Canales de Calcio/análisis , Canales de Calcio/ultraestructura , Proteínas de Ciclo Celular , Movimiento Celular , Células Cultivadas , Proteínas del Citoesqueleto/análisis , Pulpa Dental/ultraestructura , Dentina/ultraestructura , Chaperoninas del Grupo II , Proteínas de Choque Térmico/análisis , Humanos , Cinesinas/análisis , Ratones , Ratones Noqueados , Proteínas Asociadas a Microtúbulos , Diente Molar/ultraestructura , Chaperonas Moleculares/análisis , Morfogénesis/fisiología , Fibras Nerviosas/ultraestructura , Proteínas/análisis , Canales Catiónicos TRPP/análisis , Factores de Transcripción/análisis , Tubulina (Proteína)/análisis
17.
Osteoporos Int ; 20(7): 1107-16, 2009 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-19468663

RESUMEN

SUMMARY: The Global Longitudinal study of Osteoporosis in Women (GLOW) is a prospective cohort study involving 723 physicians and 60,393 women subjects >or=55 years. The data will provide insights into the management of fracture risk in older women over 5 years, patient experience with prevention and treatment, and distribution of risk among older women on an international basis. INTRODUCTION: Data from cohort studies describing the distribution of osteoporosis-related fractures and risk factors are not directly comparable and do not compare regional differences in patterns of patient management and fracture outcomes. METHODS: The GLOW is a prospective, multinational, observational cohort study. Practices typical of each region were identified through primary care networks organized for administrative, research, or educational purposes. Noninstitutionalized patients visiting each practice within the previous 2 years were eligible. Self-administered questionnaires were mailed, with 2:1 oversampling of women >or=65 years. Follow-up questionnaires will be sent at 12-month intervals for 5 years. RESULTS: A total of 723 physicians at 17 sites in ten countries agreed to participate. Baseline surveys were mailed (October 2006 to February 2008) to 140,416 subjects. After the exclusion of 3,265 women who were ineligible or had died, 60,393 agreed to participate. CONCLUSIONS: GLOW will provide contemporary information on patterns of management of fracture risk in older women over a 5-year period. The collection of data in a similar manner in ten countries will permit comparisons of patient experience with prevention and treatment and provide insights into the distribution of risk among older women on an international basis.


Asunto(s)
Fracturas Óseas/prevención & control , Osteoporosis Posmenopáusica/complicaciones , Anciano , Australia , Europa (Continente) , Femenino , Fracturas Óseas/etiología , Salud Global , Humanos , Estudios Longitudinales , Persona de Mediana Edad , América del Norte , Osteoporosis Posmenopáusica/diagnóstico , Selección de Paciente , Estudios Prospectivos , Factores de Riesgo , Encuestas y Cuestionarios
18.
Calcif Tissue Int ; 84(6): 502-9, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19458889

RESUMEN

Low Intensity Electrical Stimulation (LIES) has been used for bone repair, but little is known about its effects on bone after menopause. Osteocytes probably play a role in mediating this physical stimulus and they could act as transducers through the release of biochemical signals, such as nitric oxide (NO). The aim of the present study was to investigate the effects of LIES on bone structure and remodeling, NOS expression and osteocyte viability in ovariectomized (OVX) rats. Thirty rats (200-220 g) were divided into 3 groups: SHAM, OVX, and OVX subjected to LIES (OVX + LIES) for 12 weeks. Following the protocol, rats were sacrificed and tibias were collected for histomorphometric analysis and immunohistochemical detection of endothelial NO synthase (eNOS), inducible NOS (iNOS), and osteocyte apoptosis (caspase-3 and TUNEL). OVX rats showed significant (p < 0.05 vs. SHAM) decreased bone volume (10% vs. 25%) and trabecular number (1.7 vs. 3.9), and increased eroded surfaces (4.7% vs. 3.2%) and mineralization surfaces (15.9% vs. 7.7%). In contrast, after LIES, all these parameters were significantly different from OVX but not different from SHAM. eNOS and iNOS were similarly expressed in subperiosteal regions of tibiae cortices of SHAM, not expressed in OVX, and similarly expressed in OVX + LIES when compared to SHAM. In OVX, the percentage of apoptotic osteocytes (24%) was significantly increased when compared to SHAM (11%) and OVX + LIES (8%). Our results suggest that LIES counteracts some effects of OVX on bone tissue preserving bone structure and microarchitecture, iNOS and eNOS expression, and osteocyte viability.


Asunto(s)
Huesos/fisiología , Terapia por Estimulación Eléctrica , Menopausia , Óxido Nítrico/metabolismo , Osteocitos/fisiología , Animales , Apoptosis/fisiología , Huesos/metabolismo , Huesos/ultraestructura , Caspasa 3/metabolismo , Supervivencia Celular/fisiología , Femenino , Óxido Nítrico Sintasa de Tipo II/metabolismo , Óxido Nítrico Sintasa de Tipo III/metabolismo , Osteocitos/metabolismo , Osteocitos/ultraestructura , Ovariectomía , Ratas , Ratas Wistar , Tibia/citología , Tibia/fisiología
20.
Osteoporos Int ; 20(11): 1895-902, 2009 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19296144

RESUMEN

UNLABELLED: Two studies in postmenopausal women with osteoporosis provide information about the efficacy and safety of dosing oral risedronate 5 mg daily at a time other than before breakfast (i.e., 2 h before and 2 h after any food and drink other than plain water). A significant increase in lumbar spine BMD was observed for both treatment regimens in the two studies. However, smaller increases in lumbar spine BMD were observed with flexible dosing versus before-breakfast dosing. Geographic region, compliance, and consistency of dosing time appear to affect the amount of increase in BMD observed with flexible dosing. INTRODUCTION: Two studies in postmenopausal women with osteoporosis provide additional information about the efficacy and safety of dosing oral risedronate 5 mg daily at a time other than before breakfast (i.e., 2 h before and 2 h after any food and drink other than plain water). METHODS: One study, flexible dosing, was a 6-month North American study in 730 patients randomized to before-breakfast dosing or flexible dosing later in the day. A second study, IMPACT, was a large (N = 2382), 1-year multinational study in patients that chose their dosing regimen (before breakfast or later in the day). These studies were used to examine the bone mineral density (BMD) response with different dosing regimens. RESULTS: A significant increase in lumbar spine BMD was observed for both treatment regimens in the two studies. However, in both studies, the flexible dosing group had a smaller increase from baseline compared to the before-breakfast regimen (ratio of flexible dosing to before breakfast: flexible dosing study, 0.52; IMPACT study, 0.75). In addition, a relationship between geographic region and BMD response was observed with flexible dosing in both studies. Patients in the flexible dosing group who had greater dosing compliance (based on the number of times the bottle was opened) and consistency of dosing time (bottle opened within a 1.5-h window) had a greater increase in lumbar spine BMD. CONCLUSION: Results of these two studies demonstrate that overall flexible dosing of risedronate leads to smaller BMD gains compared to before-breakfast dosing. This result may be due to poorer adherence to the flexible dosing instructions that may be more pronounced in patients in certain geographic regions. If patients cannot abide by before-breakfast dosing and flexible dosing is an approved option, one can expect suboptimal BMD results with flexible dosing.


Asunto(s)
Conservadores de la Densidad Ósea/administración & dosificación , Ácido Etidrónico/análogos & derivados , Osteoporosis Posmenopáusica/tratamiento farmacológico , Anciano , Densidad Ósea/efectos de los fármacos , Conservadores de la Densidad Ósea/efectos adversos , Conservadores de la Densidad Ósea/uso terapéutico , Esquema de Medicación , Ácido Etidrónico/administración & dosificación , Ácido Etidrónico/efectos adversos , Ácido Etidrónico/uso terapéutico , Femenino , Humanos , Vértebras Lumbares/fisiopatología , Persona de Mediana Edad , Osteoporosis Posmenopáusica/fisiopatología , Cooperación del Paciente , Ácido Risedrónico , Método Simple Ciego
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA