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1.
BMC Health Serv Res ; 22(1): 596, 2022 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-35505358

RESUMEN

BACKGROUND: Interventions to increase person-centeredness in hospital care for persons with psychotic illness are needed. Changing care delivery is however a complex venture, requiring staff to reconsider their mindsets and ways of working. A multidisciplinary educational intervention for hospital staff at four wards was launched to increase person-centeredness in the care of patients with schizophrenia and similar psychoses. This study aims to explore staff experiences of working to increase person-centeredness. METHODS: A heterogenic sample of staff (n = 23) from all participating wards were recruited for six focus group interviews. Semi-structured questions covered staff perceptions of person-centered care and the process of increasing person-centeredness. Transcribed data was analyzed using thematic analysis according to Braun and Clarke. RESULTS: Staff viewed person-centered care as an approach rather than a method. They described central aspects of person-centered care, such as recognizing the patient as a capable person who can participate in her/his care. Statements further showed how these core features were put into practice. Changes related to the intervention were presented in terms of evolving patient and staff roles, improved contact with patients, more flexible care routines, and a more positive ward climate. Neither psychotic symptoms nor involuntary status were considered barriers for person-centered care, but organizational factors beyond staff control seemed to impact on implementation. CONCLUSIONS: After implementation, participants displayed good understanding of the core concepts of person-centered care in both thinking and action. They attributed several improvements in the care milieu to an increased level of person-centeredness. Psychotic behavior and involuntary treatment did not present major barriers to person-centered care. Findings suggest person-centered care is feasible in the psychosis inpatient setting and could improve quality of care. TRIAL REGISTRATION: The study is part of a larger study evaluating the intervention Person-Centered Psychosis Care (PCPC). It was registered retrospectively at clinicaltrials.gov , identifier NCT03182283 .


Asunto(s)
Atención Dirigida al Paciente , Trastornos Psicóticos , Femenino , Humanos , Pacientes Internos , Atención Dirigida al Paciente/métodos , Trastornos Psicóticos/terapia , Estudios Retrospectivos , Autocuidado
2.
J Fish Biol ; 88(5): 2081-7, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-27095288

RESUMEN

A new, image-based, tritiated ligand technique for measuring cardiac ß2 -adrenoceptor (ß2 -AR) binding characteristics was developed and validated with adult rainbow trout Oncorhynchus mykiss hearts so that the tissue limitation of traditional receptor binding techniques could be overcome and measurements could be made in hearts nearly 14-times smaller than previously used. The myocardial cell-surface (functional) ß2 -AR density of O. nerka smolts sampled at the headwaters of the Chilko River was 54·2 fmol mg protein(-1) and about half of that previously found in return migrating adults of the same population, but still more than twice that of adult hatchery O. mykiss (21·1 fmol mg protein(-1) ). This technique now opens the possibility of investigating cardiac receptor density in a much wider range of fish species and life stages.


Asunto(s)
Miocardio/metabolismo , Oncorhynchus mykiss/metabolismo , Receptores Adrenérgicos beta 2/metabolismo , Animales , Femenino , Ligandos , Receptores Adrenérgicos , Ríos , Salmón , Tritio
3.
Am J Transplant ; 15(10): 2636-45, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26372837

RESUMEN

A kidney-paired donation (KPD) pool consists of transplant candidates and their incompatible donors, along with nondirected donors (NDDs). In a match run, exchanges are arranged among pairs in the pool via cycles, as well as chains created from NDDs. A problem of importance is how to arrange cycles and chains to optimize the number of transplants. We outline and examine, through example and by simulation, four schemes for selecting potential matches in a realistic model of a KPD system; proposed schemes take account of probabilities that chosen transplants may not be completed as well as allowing for contingency plans when the optimal solution fails. Using data on candidate/donor pairs and NDDs from the Alliance for Paired Donation, the simulations extend over 8 match runs, with 30 pairs and 1 NDD added between each run. Schemes that incorporate uncertainties and fallbacks into the selection process yield substantially more transplants on average, increasing the number of transplants by as much as 40% compared to a standard selection scheme. The gain depends on the degree of uncertainty in the system. The proposed approaches can be easily implemented and provide substantial advantages over current KPD matching algorithms.


Asunto(s)
Algoritmos , Técnicas de Apoyo para la Decisión , Selección de Donante/métodos , Trasplante de Riñón , Donadores Vivos , Incertidumbre , Simulación por Computador , Selección de Donante/organización & administración , Humanos , Modelos Estadísticos
4.
Int J Obes (Lond) ; 34(7): 1188-90, 2010 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-20065976

RESUMEN

Waist-to-height ratio (WHtR) is purported to offer a simpler index of health risk than body mass index (BMI) in children as it requires no adjustment for age or sex. Little is known regarding the usefulness of WHtR in different ethnic groups. The aim of this study was to compare the WHtR cutpoints associated with BMI definitions of overweight and obesity in a nationally representative sample of New Zealand children. Height, weight and waist circumference were measured in 3006 children (51.5% male) aged 5-14 years (n=1107 Maori, n=985 Pacific and n=924 New Zealand European and Others (NZEO)). A WHtR >0.5 was more common in Pacific (43.4%) and Maori (33.1%) children than in NZEO children (20.8%, P<0.001), with 25.6% of children overall being above this cutoff. Although ethnicity influenced the relationship between BMI and WHtR (P<0.01), differences were clinically insignificant as illustrated by the similarity in WHtR values for a given BMI (WHtR of 0.47 in Maori, 0.46 in Pacific and 0.48 in European boys at the 85th BMI percentile). The present results suggest that having WHtR values >0.5 should be equally useful in evaluating cardiovascular health risks in groups of Maori, Pacific and NZEO children.


Asunto(s)
Composición Corporal/fisiología , Estatura/fisiología , Enfermedades Cardiovasculares/etnología , Obesidad/etnología , Circunferencia de la Cintura/fisiología , Adolescente , Índice de Masa Corporal , Enfermedades Cardiovasculares/epidemiología , Enfermedades Cardiovasculares/etiología , Niño , Preescolar , Femenino , Humanos , Masculino , Nueva Zelanda/epidemiología , Obesidad/complicaciones , Obesidad/epidemiología
5.
Osteoporos Int ; 21(2): 351-7, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19436938

RESUMEN

UNLABELLED: Bone, muscle, and fat may affect gait and balance in older adults. Osteoporosis was prevalent in low muscle mass participants and related to gait and balance deficits. Low muscle combined with high fat mass had more functional deficits and poorer bone health, which has implications for falls risk and fractures. INTRODUCTION: Decreasing bone density and muscle mass and increasing fat mass may act synergistically to affect gait and balance in older adults. METHODS: One hundred eighty-three older adults (age 72.7 +/- 6 years, range 56-93; body mass index 28.2 +/- 4.9, range 16.6-46.0) were recruited from a New Zealand falls prevention intervention trial. Total and appendicular skeletal muscle mass (ASM), percent fat, and bone mineralization were assessed by dual energy X-ray absorptiometry and used to characterize normal lean (NL, n = 51), sarcopenic (SS, n = 18), sarcopenic obese (SO, n = 29), and obese (OO, n = 85) phenotypes. Functional performance was assessed using timed up and go, chair stand, single leg stand, and step test. Regression models were adjusted for age, sex, medications, and physical activity. RESULTS: Femoral neck osteoporosis was present in 22% SS, 17% SO, 12% NL, and 7% OO. Femoral neck osteoporosis with low ASM predicted poor chair stand performance (beta -3.3, standard error 1.6, p = 0.04). SO scored lowest on the chair stand (p = 0.03) and step test (p = 0.03). Higher ASM predicted faster timed up and go performance (p = 0.001). CONCLUSIONS: Osteoporosis was prevalent in low ASM groups (SS and SO) and related to gait and balance deficits, particularly in the SO. This has implications for falls risk, fractures, and interventions.


Asunto(s)
Trastornos Neurológicos de la Marcha/etiología , Obesidad/complicaciones , Osteoporosis/complicaciones , Equilibrio Postural , Trastornos de la Sensación/etiología , Accidentes por Caídas/prevención & control , Accidentes por Caídas/estadística & datos numéricos , Anciano , Anciano de 80 o más Años , Composición Corporal , Índice de Masa Corporal , Densidad Ósea , Femenino , Cuello Femoral/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Actividad Motora , Osteoporosis/fisiopatología , Sarcopenia/complicaciones , Taichi Chuan
6.
J Comp Physiol B ; 190(6): 717-730, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32770260

RESUMEN

We tested the hypothesis that cardiorespiratory differences known to exist among adult sockeye salmon populations also exist in the juveniles. To test this hypothesis, we compared cardiac contractility and adrenergic responsiveness of juvenile sockeye salmon from two geographically isolated populations that were reared from eggs under common garden conditions and at two acclimation temperatures (5 °C and 14 °C). However, we found no substantive differences in the force-frequency response (FFR) and the cardiac pumping capacity of juveniles from Weaver Creek and Chilko River populations, even when we considered wild-reared juveniles from one of the populations. An unexpected discovery for all fish groups at 5 °C was a rather flat FFR during tonic ß-adrenergic stimulation (ßAR) stimulation. Curiously, while active tension nearly doubled with maximum ßAR stimulation at low pacing frequencies for all fish groups, a negative FFR with maximum ßAR stimulation meant that this inotropic benefit was lost at the highest pacing frequency (0.8 Hz). Active tension with tonic ßAR stimulation was similar at 14 °C, but maximum pacing frequency doubled and all fish groups displayed a modest negative FFR. Maximum ßAR stimulation again doubled active tension and this benefit was retained even at the highest pacing frequency (1.6 Hz) at 14 °C. Even though subtle population differences were apparent for the FFR and pumping capacity, their biological significance is unclear. What is clear, however, is that the cardiac pumping capacity of juvenile sockeye would benefit more from ßAR stimulation swimming at 15 °C than when swimming at 5 °C.


Asunto(s)
Aclimatación/fisiología , Salmón/fisiología , Temperatura , Función Ventricular , Agonistas Adrenérgicos beta/farmacología , Animales , Ventrículos Cardíacos/efectos de los fármacos , Isoproterenol/farmacología , Contracción Miocárdica/efectos de los fármacos
7.
Eur Respir J ; 32(1): 85-91, 2008 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-18353855

RESUMEN

Respiratory function is impaired in obesity but there are limitations with body mass index and skin-fold thickness in assessing this effect. The present authors hypothesised that the regional distribution of body fat and lean mass, as measured by dual-energy X-ray absorptiometry (DXA), might be more informative than conventional measurements of total body fat. In total, 107 subjects (55 female, 51.4%) aged 20-50 yrs with no respiratory disease were recruited. Respiratory function tests, anthropometric measurements and a DXA scan were performed. Partial correlation and linear regression analyses were used to explore the effect of adiposity and lean body mass on respiratory function. The majority of respiratory function parameters were significantly correlated with DXA and non-DXA measurements of body fat. Neither thoracic nor abdominal fat had a greater effect. There were some differences in the effect of adiposity between the sexes. Respiratory function was negatively associated with lean body mass in females but positively associated in males. This disappeared after adjustment in females but remained in males. The effects of thoracic and abdominal body fat on respiratory function are comparable but cannot be separated from one another.


Asunto(s)
Adiposidad/fisiología , Ventilación Pulmonar/fisiología , Absorciometría de Fotón , Adulto , Estudios de Cohortes , Femenino , Humanos , Masculino , Persona de Mediana Edad
8.
Bioconjug Chem ; 19(11): 2113-9, 2008 Nov 19.
Artículo en Inglés | MEDLINE | ID: mdl-18925769

RESUMEN

Unavailability of fusion tags that possess both affinity and visualization properties is a hurdle for biomolecular research. Typically, either a choice is made between an affinity tag and a reporter tag or both are employed in tandem if a fusion can be made at both termini of the target biomolecule. In this work, we have developed a site-specific genetic fusion approach employing DsRed-Monomer, a red fluorescent protein, that provides for both affinity and reporter functionality in a single tag. As a proof-of-concept, two fusion proteins, bradykinin-DsRed-Monomer and calmodulin-DsRed-Monomer, were prepared for the study. These fusion proteins were purified using a copper-immobilized column based on the inherent copper-binding property of DsRed-Monomer. Spectroscopic characterization of fusion proteins and comparison with native DsRed-Monomer showed no effect of fusion on the properties of DsRed-Monomer. Further, bradykinin-DsRed-Monomer was employed in the development of a competitive fluorescence immunoassay for the peptide bradykinin. Calmodulin-DsRed-Monomer was used to detect binding of the calmodulin ligand chlorpromazine, based on a change in the fluorescence of DsRed-Monomer upon binding of chlorpromazine to calmodulin. The studies performed demonstrate the application of DsRed-Monomer as a dual function tag indicating the potential usefulness of DsRed-monomer in proteomics and biomolecular research.


Asunto(s)
Marcadores de Afinidad/metabolismo , Proteínas Luminiscentes/metabolismo , Coloración y Etiquetado/métodos , Marcadores de Afinidad/química , Animales , Anticuerpos/inmunología , Anticuerpos/metabolismo , Bradiquinina/análisis , Bradiquinina/inmunología , Bradiquinina/metabolismo , Calmodulina/análisis , Calmodulina/metabolismo , Bovinos , Clorpromazina/farmacología , Cobre/química , Relación Dosis-Respuesta a Droga , Escherichia coli/genética , Fluorescencia , Proteínas Inmovilizadas/inmunología , Proteínas Inmovilizadas/metabolismo , Proteínas Luminiscentes/química , Unión Proteica/efectos de los fármacos , Proteínas Recombinantes de Fusión/biosíntesis
9.
J Bone Miner Res ; 6(11): 1177-81, 1991 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-1805541

RESUMEN

The estrogen agonist and antagonist clomiphene citrate has been shown to prevent bone loss induced by ovariectomy in the rat. In young women estrogen-deficiency bone loss is a clinical problem associated with the use of luteinizing hormone releasing hormone (LHRH) agonists, such as buserelin, to treat endometriosis. The aim of this study was to determine whether clomiphene citrate (10 mg/kg body weight per week orally) would prevent the osteopenic effect of buserelin (25 micrograms/kg body weight per day SC) in the rat. Four groups of animals with 45Ca-labeled skeletons were studied for 4 weeks: group A, placebo controls; group B, buserelin; group C, clomiphene; and group D, buserelin + clomiphene. Bone resorption was monitored by measuring the urinary excretion of 45Ca and hydroxyproline. Clomiphene slowed bone breakdown and inhibited the osteopenic effect of buserelin. Total-body calcium values (mean +/- SD) were (mg) 2635 +/- 181, 2267 +/- 85, 2566 +/- 126, and 2624 +/- 77 in groups A to D, respectively. Osteopenia was present only in group B (P less than 0.001). Interestingly buserelin lowered blood 17 beta-estradiol and uterine weights to a similar extent in the presence and absence of clomiphene. Because clomiphene inhibited estrogen-deficiency bone loss in buserelin-treated rats without depressing the hypoestrogenic action of this LHRH agonist, it is suggested that the use of clomiphene to protect the skeleton during LHRH agonist therapy of endometriosis warrants further study.


Asunto(s)
Enfermedades Óseas Metabólicas/prevención & control , Resorción Ósea/tratamiento farmacológico , Buserelina/farmacología , Clomifeno/farmacología , Estrógenos/deficiencia , Animales , Enfermedades Óseas Metabólicas/inducido químicamente , Enfermedades Óseas Metabólicas/tratamiento farmacológico , Resorción Ósea/complicaciones , Calcio/orina , Endometriosis/tratamiento farmacológico , Estrógenos/sangre , Femenino , Hormona Liberadora de Gonadotropina/antagonistas & inhibidores , Hidroxiprolina/orina , Ratas , Ratas Endogámicas , Útero/efectos de los fármacos
10.
J Bone Miner Res ; 8(6): 763-9, 1993 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-8328318

RESUMEN

Androgens are believed to play a role in building and maintaining bone in the female, as well as in the male. The antiandrogen drug flutamide inhibits responses to androgens from both the gonads and the adrenals. Antiandrogens prevent androgens stimulating bone cell proliferation and differentiation in vitro, but effects of androgen blockade on bone metabolism in vivo have not been tested. The present study was undertaken to determine whether androgen blockade with flutamide (15 mg/kg body weight orally daily) would influence bone turnover or bone composition (1) in female rats with intact ovaries and (2) in rats made estrogen-deficient with the luteinizing hormone releasing hormone (LHRH) agonist, buserelin (25 micrograms/kg body weight per day SC). Four groups of rats with 45Ca-labeled skeletons were studied for 4 weeks: group A, placebo; group B, buserelin; group C, flutamide; group D, flutamide+buserelin. Total-body calcium values (mean +/- SD) were (mg) 2007 +/- 109, 1779 +/- 138 (P < 0.01 versus group A), 1818 +/- 140 (P < 0.01 versus group A), and 1690 +/- 75 (P < 0.01 versus group A) in groups A-D, respectively. Thus both buserelin and flutamide induced osteopenia. Skeletal 45Ca changes suggested buserelin-mediated estrogen deficiency bone loss was due to increased bone resorption, but flutamide-mediated androgen deficiency bone thinning was caused principally by reduced bone formation. These findings support the view that androgens play an important role in preserving bone mass in the female rat. Importantly, adequate estrogen status did not compensate for flutamide-mediated osteopenia.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Andrógenos/metabolismo , Enfermedades Óseas Metabólicas/inducido químicamente , Flutamida/farmacología , Animales , Peso Corporal/efectos de los fármacos , Densidad Ósea/efectos de los fármacos , Enfermedades Óseas Metabólicas/fisiopatología , Buserelina/farmacología , Femenino , Hidroxiprolina/orina , Tamaño de los Órganos/efectos de los fármacos , Ratas , Ratas Wistar , Útero/efectos de los fármacos
11.
J Bone Miner Res ; 11(7): 977-83, 1996 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-8797119

RESUMEN

To determine whether the uterus plays any role in mediating the ability of estrogen to conserve bone in the rat, eight groups of animals (n = 8) with their skeletons labeled with 45Ca were studied. Rats were ovariectomized (OVX), hysterectomized (Hyst), or given sham operations (Sham) and then pair-fed a low-hydroxyproline casein diet for 4 weeks. The groups were treated orally with 17 beta-estradiol (E2) or vehicle, and serial measurements of biochemical markers of bone breakdown were made in weeks 1, 2, and 4. The femur density was measured by dual-energy X-ray absorptiometry (DXA), and skeletal calcium and 45Ca content were determined chemically. Final total body calcium values (mg) in the eight treatment groups were (means +/- SD): Sham, 2573 +/- 179; Sham + E2, 2635 +/- 159; Hyst, 2537 +/- 151; Hyst + E2, 2410 +/- 151; OVX, 2189 +/- 146; OVX + E2, 2559 +/- 172; OVX/Hyst, 2138 +/- 132; and OVX/Hyst + E2, 2460 +/- 140. Ovariectomy raised biochemical markers of bone resorption (urinary 45Ca, hydroxyproline, and deoxypyridinoline), lowered DXA bone mineral density, and reduced total body calcium and 45Ca content in both Hyst and Sham-Hyst animals (p < 0.001), whereas E2 treatment prevented these changes. Hysterectomy did not impair the ability of E2 to conserve bone in OVX rats. Thus, we conclude that estrogen-mediated induction of growth factors from uterine tissue does not play an essential role in mediating the bone-conserving actions of estrogen in the rat.


Asunto(s)
Huesos/fisiopatología , Estradiol/uso terapéutico , Terapia de Reemplazo de Estrógeno , Histerectomía/efectos adversos , Osteoporosis/tratamiento farmacológico , Ovario/fisiología , Útero/fisiología , Animales , Factores Biológicos/fisiología , Evaluación Preclínica de Medicamentos , Femenino , Ovariectomía , Ratas , Ratas Wistar , Estimulación Química
12.
J Bone Miner Res ; 15(10): 2011-8, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11028455

RESUMEN

Predictors of childhood fractures have not been investigated previously. This study was undertaken to determine whether a previous history of forearm fracture, low bone mineral density (BMD; both areal bone mineral density [aBMD, g/cm2] and volumetric bone mineral apparent density [BMAD, g/cm3]), or anthropometry, influence fracture risk in young girls. At baseline, two cohorts of girls, aged 3-15 years, were evaluated: 100 had recently broken a forearm (group 1) and 100 were fracture free (group 2). Four years later we restudied 170 of these girls (82 from group 1 and 88 from group 2). We now report the relationships of previous fracture history, baseline BMD (measured by dual-energy X-ray absorptiometry), baseline weight, and height to risk of new fracture. More new fractures occurred in group 1 (37 fractures in 24 girls) than in group 2 (8 fractures in 7 girls; p = 0.0007). The independent predictors for occurrence of a new fracture at any skeletal site in a multivariate model adjusting for age, weight, total body aBMD, and fracture history were previous fracture (hazard ratio [HR], 3.28; 95% CI, 1.41-7.64); age (HR per 1-year increase, 0.91; 95% CI, 0.84-0.99); total body aBMD (HR per 1 SD decrease, 1.92; 95% CI, 1.31-2.81); and body weight (HR per 1 SD increase, 1.49; 95% CI, 1.06-2.08). Girls with two risk factors together had substantially greater fracture risk: previous fracture and low spinal BMAD (HR, 9.4; 95% CI, 2.8-32.0), previous fracture and high body weight (HR, 10.2; 95% CI, 2.8-37.6), or previous fracture and low total body aBMD (HR, 13.0; 95% CI, 3.9-43.1). We conclude that previous forearm fracture, low total body aBMD, low spinal BMAD, and high body weight each increase risk of new fractures within 4 years in young girls. Interventions to reduce the risk of fractures, particularly forearm fractures, in girls warrant further study.


Asunto(s)
Densidad Ósea , Fracturas Óseas/epidemiología , Fracturas Óseas/etiología , Fracturas del Radio/complicaciones , Fracturas del Cúbito/complicaciones , Absorciometría de Fotón , Adolescente , Antropometría , Niño , Preescolar , Femenino , Fracturas Óseas/complicaciones , Fracturas Óseas/fisiopatología , Humanos , Estudios Longitudinales , Análisis Multivariante , Valor Predictivo de las Pruebas , Pubertad , Fracturas del Radio/fisiopatología , Factores de Riesgo , Fracturas del Cúbito/fisiopatología
13.
J Bone Miner Res ; 13(1): 143-8, 1998 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-9443800

RESUMEN

In childhood, the most common site of fracture is the distal forearm. To determine whether young girls with these fractures have low bone density more commonly than fracture-free controls, we measured bone density at the radius, spine, hip, and whole body and total body bone mineral content, lean tissue mass, and fat mass by dual-energy X-ray absorptiometry in 100 Caucasian girls aged 3-15 years with recent distal forearm fractures and 100 age- and gender-matched controls. Bone density (age-adjusted ratios of all cases:controls with 95% confidence intervals) was lower in cases at the ultradistal radius 0.963 (0.930-0.996), 33% radius 0.972 (0.945-0.999), lumbar spine 0.945 (0.911-0.980), hip trochanter 0.952 (0.918-0.988), and total body 0.978 (0.961-0.995). Moreover, osteopenia (defined as Z score below -1), was more common in cases than controls (p < 0.05) in the forearm, spine, and hip, with one third of fracture cases having low spinal density. Odds ratios (95% confidence intervals) for low bone density were: ultradistal radius, 2.2 (1.1-4.6); lumbar spine, L2-L4, 2.6 (1.3-4.9); and femur trochanter, 2.0 (1.0-3.9). Fracture patients aged 8-10 years weighed more (mean +/- SD) than age-matched controls (37.2+/-8.0 kg vs. 32.5+/-6.6 kg, p < 0.01) while older patients reported lower current and past calcium intakes than matched controls (p < 0.05). We conclude that low bone density is more common throughout the skeleton in girls with forearm fractures than in those who have never broken a bone, supporting the view that low bone density may contribute to fracture risk in childhood.


Asunto(s)
Densidad Ósea , Fracturas del Radio/diagnóstico por imagen , Fracturas del Radio/fisiopatología , Fracturas del Cúbito/diagnóstico por imagen , Fracturas del Cúbito/fisiopatología , Adolescente , Niño , Preescolar , Femenino , Fémur/diagnóstico por imagen , Fémur/fisiología , Estado de Salud , Humanos , Pubertad , Radiografía , Radio (Anatomía)/diagnóstico por imagen , Radio (Anatomía)/fisiopatología
14.
Endocrinology ; 122(2): 482-7, 1988 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-3338411

RESUMEN

To examine the interactions between estrogen deficiency and glucocorticoid excess on bone metabolism the osteopenic effects of a standard dose of prednisolone (2 mg/kg BW.day) were studied in sham-ovariectomized (Sham-OVX), ovariectomized (OVX), and OVX rats given replacement beta-estradiol (OVX + E2). For 12 weeks six groups of female albino rats aged 4 months which had their skeletons labeled with 45Ca were fed matched amounts of low-calcium (0.1% Ca) hydroxyproline-free diet. The six treatment groups were: group 1, Sham-OVX; group 2, Sham-OVX + prednisolone; group 3, OVX; group 4, OVX + prednisolone; group 5, OVX + E2; group 6, OVX + E2 + prednisolone. Bone resorption was estimated by studying the urinary excretion of hydroxyproline and 45Ca. Parathyroid function was assessed indirectly from urinary cAMP excretion. Treatments did not influence parathyroid activity or serum levels of calcium or 1,25-dihydroxyvitamin D. However, ovariectomy increased bone resorption and induced osteopenia whereas prednisolone decreased bone resorption and formation and caused osteopenia. Ovariectomy increased the rate of bone resorption in prednisolone-treated rats; prednisolone lowered the rates of bone resorption and formation in OVX rats. The osteopenic effects of prednisolone and ovariectomy were additive and independent. E2 protected bone from the osteopenic effects of ovariectomy but did not affect bone loss induced by prednisolone. These results suggest prophylactic estrogen should help to avoid bone loss from estrogen deficiency in patients requiring chronic high dose glucocorticoid treatment.


Asunto(s)
Resorción Ósea/efectos de los fármacos , Huesos/análisis , Estradiol/farmacología , Ovariectomía , Prednisolona/farmacología , Animales , Calcio/orina , Femenino , Hidroxiprolina/orina , Ratas
15.
Endocrinology ; 119(5): 2148-54, 1986 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-3769866

RESUMEN

The effects of dietary sodium chloride supplements (8 g/100 g diet) on parathyroid function, serum 1,25-dihydroxyvitamin D [1,25-(OH)2D], calcium balance, bone metabolism, and bone composition were studied in rats treated with prednisolone (2 mg/kg w X day) for 12 weeks. Animals on a low calcium diet (0.1% Ca) received the following treatments: group 1, control; group 2, NaCl; group 3, prednisolone; group 4, NaCl plus prednisolone. Parathyroid function was assessed indirectly from urinary cAMP excretion: bone resorption was estimated by studying urinary hydroxyproline excretion and mobilization of 45Ca from bone. Dietary salt loading increased the urinary excretion of calcium, 45Ca, cAMP, and hydroxyproline and raised serum 1,25-(OH)2D and net calcium absorption, but lowered calcium retention, femoral calcium, and total body calcium. Prednisolone slowed body growth and lowered net calcium absorption, calcium retention, femoral calcium, and total body calcium. Urinary calcium excretion was higher in rats receiving salt and prednisolone in combination than in animals taking salt without prednisolone, but other responses to salt and prednisolone were independent. Thus, salt and prednisolone each elicit osteopenia, and salt causes bone loss in rats receiving prednisolone. The osteopenic effect of salt is attributed to primary augmentation of urinary calcium excretion and secondary increases in PTH-medicated bone resorption. Although salt-treated rats have higher blood levels of 1,25-(OH)2D, bone loss occurs because alimentary calcium absorption is not elevated sufficiently to offset urinary calcium losses. Prednisolone lowers bone formation and net calcium absorption without lowering serum 1,25-(OH)2D values. The parathyroid-vitamin D axis remains intact in prednisolone-treated rats, as they show increases in PTH and 1,25-(OH)2D after salt treatment.


Asunto(s)
Huesos/metabolismo , Calcitriol/sangre , Calcio/metabolismo , Dieta , Homeostasis , Glándulas Paratiroides/efectos de los fármacos , Prednisolona/farmacología , Cloruro de Sodio/administración & dosificación , Animales , Peso Corporal/efectos de los fármacos , Resorción Ósea , Femenino , Homeostasis/efectos de los fármacos , Ratas , Sodio/metabolismo , Cloruro de Sodio/farmacología
16.
Am J Clin Nutr ; 72(2): 490-5, 2000 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-10919946

RESUMEN

BACKGROUND: A central fat pattern has adverse health implications in both children and adults. Because adiposity tracks from childhood into adulthood, the ability of simple anthropometric techniques to correctly measure truncal adiposity in childhood needs to be assessed. OBJECTIVES: We sought to assess the validity of waist circumference, waist-to-hip ratio (WHR), and the conicity index as indicators of trunk fat mass in children and adolescents. DESIGN: Trunk fat mass (kg) was measured with dual-energy X-ray absorptiometry in 278 girls and 302 boys aged 3-19 y. Receiver operating characteristic (ROC) curves and areas under the curves (AUCs) for the ROCs were calculated to compare the relative abilities of the anthropometric measures to correctly identify children with high trunk fat mass (z score for our study population of > or =1). RESULTS: The 80th percentile for waist circumference correctly identified 89% of girls and 87% of boys with high trunk fat mass (sensitivity) and 94% of girls and 92% of boys with low trunk fat mass (specificity). Waist circumference performed significantly better as an index of trunk fat mass than did WHR or the conicity index, as shown by the AUCs in girls and boys, respectively: waist circumference AUCs = 0.97 and 0.97, conicity index AUCs = 0.80 and 0.81, and WHR AUCs = 0.73 and 0.71. Our cutoffs for high trunk fat mass and high waist circumference are provided for both sexes for each year of age. CONCLUSION: Waist circumference provides a simple yet effective measure of truncal adiposity in children and adolescents.


Asunto(s)
Tejido Adiposo , Composición Corporal , Obesidad/prevención & control , Abdomen , Absorciometría de Fotón , Adolescente , Adulto , Área Bajo la Curva , Constitución Corporal , Niño , Protección a la Infancia , Preescolar , Femenino , Humanos , Masculino , Curva ROC , Sensibilidad y Especificidad
17.
Am J Clin Nutr ; 64(4): 546-51, 1996 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-8839498

RESUMEN

A cross-sectional study of 140 healthy, non-obese women and growing girls aged 8-27 y was undertaken to examine changes in total-body and regional fat and fat-free lean tissue mass by Tanner stage of pubertal development with dual-energy X-ray absorptiometry. Absolute fat mass and absolute fat-free lean tissue mass were higher at successive Tanner stages (1 through 5) but the proportional increase was greater for fat: total fat mass (kg) was about threefold higher in Tanner stage 5 than in stage 1 (P < 0.001), whereas lean tissue mass (kg) in Tanner stage 5 was about double that in stage 1 (P < 0.001). Furthermore, although the regional distribution of lean tissue mass in the trunk and legs remained fairly constant at different pubertal stages, the regional distribution of fat was altered significantly, becoming more central and less peripheral. Trunk fat (as a percentage of total body fat) was significantly higher at stage 5 than at stage 1 (P < 0.001). In the whole population, body mass index was positively correlated with trunk fat (r = 0.662, P < 0.0001) and negatively with leg fat (r = -0.457, P < 0.0001). We conclude that girls accumulate a higher proportion of their total adult fat mass than of their total adult lean tissue mass during puberty, and that regional fat patterns become more android and less gynoid with maturity.


Asunto(s)
Tejido Adiposo , Envejecimiento/fisiología , Composición Corporal , Pubertad/fisiología , Absorciometría de Fotón , Adolescente , Adulto , Antropometría , Constitución Corporal , Niño , Estudios Transversales , Femenino , Humanos , Nueva Zelanda
18.
Am J Clin Nutr ; 67(1): 44-9, 1998 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-9440374

RESUMEN

Receiver operating characteristic (ROC) curves were constructed to assess the value of body mass index (BMI) as a screening measure for total adiposity and to examine waist-to-hip ratio (WHR) and waist circumference as measures of central fat distribution. Body fat reference measurements were determined by dual-energy X-ray absorptiometry (DXA). The study population comprised 96 healthy white women aged 16-80 y. A positive reference test was defined as a result at or above the 75th percentile for our study population for all DXA measurements. Sensitivity and specificity were calculated at several percentile cutoffs for BMI, WHR, and waist girth. The areas under the ROC curves were calculated to compare the relative ability of each anthropometric technique to correctly classify subjects according to the reference measurement for that technique. BMI (our 75th percentile = 27.3) performed well as a screening measure of total adiposity, correctly identifying 83% of subjects with a high body fat mass while misclassifying only eight subjects [four false-negatives (subjects with high fat mass who were in the low BMI category) and four false-positives (subjects with a low fat mass who were in the high BMI category)]. The screening performance of WHR (our 75th percentile = 0.81) was lower, accurately categorizing 58% of subjects while misclassifying 28 subjects. By contrast, waist circumference (our 75th percentile = 86.9 cm) was significantly better than WHR at screening for regional fat distribution, accurately classifying 83% of subjects and misclassifying eight subjects (P < 0.05). We conclude that BMI and waist circumference provide simple yet sensitive methods for the estimation of total and central adiposity in groups of adult women.


Asunto(s)
Tejido Adiposo/patología , Constitución Corporal , Índice de Masa Corporal , Absorciometría de Fotón , Tejido Adiposo/diagnóstico por imagen , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Envejecimiento/fisiología , Femenino , Humanos , Persona de Mediana Edad , Curva ROC , Sensibilidad y Especificidad , Población Blanca
19.
Bone ; 15(5): 497-503, 1994.
Artículo en Inglés | MEDLINE | ID: mdl-7980960

RESUMEN

To examine the ability of tamoxifen (TAM) to conserve bone in the estrogen-deficient ovariectomized (OVX) rat in the presence and absence of parathyroid hormone (PTH) six groups of rats with 45Ca-labeled bones were studied for 12 weeks. Rats were OVX, parathyroidectomized (PTX), or given sham operations and treated with TAM (10 mg/kg body wt./wk subcutaneously) or TAM-vehicle. Treatments were: group 1 = Sham-OVX; group 2 = Sham-OVX + TAM; group 3 = OVX; group 4 = OVX + TAM; group 5 = OVX + PTX; and group 6 = OVX + PTX + TAM. To monitor bone resorption serial measurements of urinary hydroxyproline and 45Ca excretion were made during the study. Ovariectomy raised these markers of bone breakdown and caused significant osteopenia, whereas TAM prevented ovariectomy increasing urinary hydroxyproline or 45Ca and conserved bone. Final total body calcium values (TBCa) in groups 1-6, respectively, were (mg +/- SD): 3240 +/- 300; 3260 +/- 289; 2750 +/- 231; 3212 +/- 312; 2742 +/- 199; and 3387 +/- 252. Thus ovariectomy reduced TBCa similarly in the presence and absence of the parathyroids (p < 0.001). In contrast TAM fully protected both PT-intact and PTX rats from the osteopenic effect of ovariectomy, despite the fact that PTX rats had a lower rate of bone turnover than PT-intact rats. However, TAM-treated OVX rats had shorter femora than OVX rats given TAM-vehicle, suggesting that TAM suppresses growth of the long bones to some degree in estrogen-deficient animals.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Resorción Ósea/tratamiento farmacológico , Huesos/efectos de los fármacos , Osteoporosis Posmenopáusica/tratamiento farmacológico , Hormona Paratiroidea/fisiología , Tamoxifeno/farmacología , Análisis de Varianza , Animales , Peso Corporal/efectos de los fármacos , Huesos/fisiología , Calcio/metabolismo , Modelos Animales de Enfermedad , Estrógenos/deficiencia , Femenino , Humanos , Hidroxiprolina/orina , Inyecciones Subcutáneas , Ovariectomía/efectos adversos , Paratiroidectomía , Ratas , Ratas Wistar , Espectrofotometría Atómica , Tamoxifeno/administración & dosificación , Tamoxifeno/uso terapéutico
20.
Bone ; 19(6): 645-9, 1996 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-8968032

RESUMEN

In elderly women, a long hip axis length has been shown to increase the risk of hip fracture. However, to date, few measurements of hip geometry have been reported in children and adolescents. The present cross-sectional dual-energy X-ray absorptiometry (DEXA) study of 200 girls aged 3-16 years was undertaken to determine at what age adult hip geometry is achieved and to examine possible influences of anthropometry and body composition on the development of femur axis length (FAL) and femur width (FW) during growth. Adult values for FAL and FW were achieved by age 15 years. Age, height, lean tissue mass, total body bone mineral content (BMC), weight, FW, neck of femur bone mineral density (BMD), and fat were each strongly associated with FAL (p < 0.001), the highest correlations being with age (r = 0.917) and height (r = 0.906). However, after adjusting for age and height, only lean tissue mass, weight, and fat mass remained significantly associated with FAL, suggesting that bone mineral accrual does not influence variance in FAL. Our results also suggested that fat mass and weight per se tended to have greater influence on FW than on FAL in age- and height-adjusted data. Twin studies indicate that 20% of adult hip axis length is associated with environmental factors. We therefore conclude that any environmental effects of physical activity or nutrition on hip geometry must occur before early teen-age years.


Asunto(s)
Absorciometría de Fotón/métodos , Fémur/crecimiento & desarrollo , Adolescente , Antropometría , Composición Corporal , Densidad Ósea , Niño , Preescolar , Estudios Transversales , Femenino , Fémur/anatomía & histología , Humanos , Población Blanca
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