RESUMO
Objectives This study aimed to test the extensor carpi radialis and cranial tibial reflexes in cats before and after anesthetic block of the brachial and lumbosacral plexus, respectively, to determine whether they depend on a myotatic reflex arc. Methods Fifty-five cats with a normal neurologic examination that were referred for elective gonadectomy were divided into group 1 (29 cats) for testing the extensor carpi radialis reflex, and group 2 (26 cats) for testing the cranial tibial reflex. In group 1, the extensor carpi radialis reflex was tested after anesthetic induction and 15 mins after brachial plexus block with lidocaine. In group 2, the cranial tibial, withdrawal and patellar reflexes were elicited in 52 hindlimbs and retested 15 mins after epidural anesthesia. Results In group 1, before the anesthetic block, 55.17% of the cats had a decreased and 44.83% had a normal extensor carpi radialis reflex. After the block, 68.96% showed a decreased and 27.59% a normal reflex. No cat had an increased or absent reflex before anesthetic block. In group 2, prior to the anesthetic block, 15.38% of the cats had a decreased cranial tibial reflex and 84.62% had a normal response, whereas after the block it was decreased in 26.92% and normal in 73.08% of the cats. None of the cats had an increased or absent reflex. Regarding the presence of both reflexes before and after anesthetic block, there was no significant difference at 1% ( P = 0.013). Conclusions and relevance The extensor carpi radialis and cranial tibial reflexes in cats are not strictly myotatic reflexes, as they are independent of the reflex arc, and may be idiomuscular responses. Therefore, they are not reliable for neurologic examination in this species.
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Gatos/fisiologia , Músculo Esquelético/inervação , Rádio (Anatomia)/fisiologia , Reflexo , Tíbia/fisiologia , Animais , Vértebras Cervicais/fisiologia , Feminino , Masculino , Bloqueio Nervoso/veterinária , Exame Neurológico/veterinária , Tempo de ReaçãoRESUMO
In a cross-sectional cohort of 450 healthy women aged 20 to 85 years, data on the density, structure, and strength of the distal radius and tibia were obtained using high-resolution peripheral quantitative computed tomography (HR-pQCT) and were adjusted for age, weight, and height. Age-dependent patterns of change differed between the sites and between the trabecular and cortical compartments. In postmenopausal women, the trabecular bone remained relatively stable at the distal tibia, but the cortical compartment changed significantly. Cortical porosity exhibited a very weak correlation with stiffness. INTRODUCTION: The aim of this study is to provide information on age-related, weight-related, and height-related changes in the volumetric bone mineral density (vBMD), structure, and biomechanical parameters of the cortical and trabecular compartments in a healthy female population using HR-pQCT. METHODS: For a cross-sectional Brazilian cohort of 450 women aged 20 to 85 years, age-related reference curves of the vBMD, structure, and biomechanical parameters of the distal radius (DR) and distal tibia (DT) were constructed and adjusted for weight and height, and comparisons between premenopausal and postmenopausal women were performed. RESULTS: Reference curves were obtained for all parameters. At the DR, age-related changes varied from -8.68% (cortical thickness [Ct.Th]) to 26.7% (trabecular separation [Tb.Sp]). At the DT, the changes varied from -12.4% (Ct.Th) to 26.3% (Tb.Sp). Cortical porosity (Ct.Po) exhibited the largest percent changes: 342.2% at the DR and 381.5% at the DT. In premenopausal women, Ct.Th remained constant; in postmenopausal women, structural trabecular parameters (trabecular number (Tb.N), trabecular thickness (Tb.Th), Tb.Sp) did not change, whereas cortical parameters and stiffness were significantly altered. Cortical vBMD showed the greatest absolute decrease at both sites, and the slopes were highly negative after menopause. Pearson correlations between stiffness (S) and HR-pCT parameters revealed a significant correlation between the densities and structures of the trabecular and cortical compartments. A weak correlation was observed between S and Ct.Po (DR r = -0.162, DT r = -0.273; p < 0.05). CONCLUSIONS: These data provide reference curves from healthy women and demonstrate that density and structural and biomechanical parameters differ between the radius and tibia and between the trabecular and cortical compartments. In postmenopausal women, the trabecular bone remained relatively stable at the tibia site, whereas the cortical compartment changed significantly.
Assuntos
Envelhecimento/fisiologia , Densidade Óssea/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Fenômenos Biomecânicos , Estatura/fisiologia , Peso Corporal/fisiologia , Estudos Transversais , Feminino , Humanos , Imageamento Tridimensional/métodos , Pessoa de Meia-Idade , Porosidade , Rádio (Anatomia)/diagnóstico por imagem , Rádio (Anatomia)/fisiologia , Valores de Referência , Tíbia/diagnóstico por imagem , Tíbia/fisiologia , Tomografia Computadorizada por Raios X/métodos , Adulto JovemRESUMO
We prepared a bone scaffold material comprising a PLGA/ß-TCP core and a Type I collagen cladding, and recombined it with bone marrow stroma stem cells (BMSCs) to evaluate its potential for use in bone tissue engineering by in vivo and in vitro experiments. PLGA/ß-TCP without a cladding was used for comparison. The adherence rate of the BMSCs to the scaffold was determined by cell counting. Cell proliferation rate was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. The osteogenic capability was evaluated by alkaline phosphatase activity. The scaffold materials were recombined with the BMSCs and implanted into a large segmental rabbit radial defect model to evaluate defect repair. Osteogenesis was assessed in the scaffold materials by histological and double immunofluorescence labeling, etc. The adherence number, proliferation number, and alkaline phosphatase expression of the cells on the bone scaffold material with core-cladding structure were significantly higher than the corresponding values in the PLGA/ß-TCP composite scaffold material (P < 0.05). An in vivo test indicated that the bone scaffold material with core-cladding structure completely degraded at the bone defect site and bone formation was completed. The rabbit large sentimental radial defect was successfully repaired. The degradation and osteogenesis rates matched well. The bone scaffold with core-cladding structure exhibited better osteogenic activity and capacity to repair a large segmental bone defect compared to the PLGA/ß-TCP composite scaffold. The bone scaffold with core-cladding structure has excellent physical properties and biocompatibility. It is an ideal scaffold material for bone tissue engineering.
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Regeneração Óssea , Células-Tronco Mesenquimais/citologia , Alicerces Teciduais/química , Animais , Fosfatos de Cálcio/efeitos adversos , Fosfatos de Cálcio/farmacologia , Proliferação de Células , Células Cultivadas , Ácido Láctico/efeitos adversos , Ácido Láctico/farmacologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/fisiologia , Osteogênese , Ácido Poliglicólico/efeitos adversos , Ácido Poliglicólico/farmacologia , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Coelhos , Rádio (Anatomia)/citologia , Rádio (Anatomia)/fisiologia , Engenharia Tecidual , Alicerces Teciduais/efeitos adversosRESUMO
To compare the independent influence of mechanical and non-mechanical factors on bone features, multiple regression analyses were performed between pQCT indicators of radius and tibia bone mass, mineralization, design and strength as determined variables, and age or time since menopause (TMP), body mass, bone length and regional muscles' areas as selected determinant factors, in Caucasian, physically active, untrained healthy men and pre- and post-menopausal women. In men and pre-menopausal women, the strongest influences were exerted by muscle area on radial features and by both muscle area and bone length on the tibia. Only for women, was body mass a significant factor for tibia traits. In men and pre-menopausal women, mass/design/strength indicators depended more strongly on the selected determinants than the cortical vBMD did (p<0.01-0.001 vs n.s.), regardless of age. However, TMP was an additional factor for both bones (p<0.01-0.001). The selected mechanical factors (muscle size, bone lengths) were more relevant than age/TMP or body weight to the development of allometrically-related bone properties (mass/design/strength), yet not to bone tissue 'quality' (cortical vBMD), suggesting a determinant, rather than determined role for cortical stiffness. While the mechanical impacts of muscles and bone levers on bone structure were comparable in men and pre-menopausal women, TMP exerted a stronger impact than allometric or mechanical factors on bone properties, including cortical vBMD.
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Rádio (Anatomia)/diagnóstico por imagem , Rádio (Anatomia)/fisiologia , Tíbia/diagnóstico por imagem , Tíbia/fisiologia , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Antropometria , Fenômenos Biomecânicos , Densidade Óssea/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pós-Menopausa , Fatores Sexuais , Tomografia Computadorizada por Raios XRESUMO
The purpose of this study was to assess the bone speed of sound (SoS) through lifetime of a large Mexican population sample by determining the SoS from the radius and tibia using quantitative ultrasound (QUS). This is a cross-sectional evaluation of participants in the Mexican Health Workers Cohort Study. QUS measurements were performed using Sunlight Omnisense 8000P; Z- and T-scores were calculated for both sexes at the distal third of the radius and midshaft tibia, both on the nondominant side. A locally weighted regression smoothing scatterplot model was used to identify different phases of bone accretion and loss. A total of 9128 participants aged 1-75 yr were measured with QUS. Bone SoS accretion began 5 yr earlier in girls than boys (p<0.05). Maximal SoS or peak bone SoS was noted at 28 yr in the radius and at 22 yr in the tibia. Postmenopausal women (45-50 yr) showed significant SOS decrease at both sites (p<0.05) compared with men. Using the locally weighted regression smoothing scatterplot model, we found 5 different phases that constitute the biological development of bone over the life course, from ages 1-6, 7-12, 12-25, 25-50, and 50-75 yr (p<0.05). Our study shows the age- and sex-dependent changes and different phases of bone development expressed by SoS measurements of the radius and tibia. The values reported in this study can be used as a reference for urban Mexican population.
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Densidade Óssea , Desenvolvimento Ósseo/fisiologia , Rádio (Anatomia) , Som , Tíbia , Adulto , Fatores Etários , Idoso , Criança , Estudos de Coortes , Estudos Transversais , Feminino , Humanos , Lactente , Masculino , México , Rádio (Anatomia)/diagnóstico por imagem , Rádio (Anatomia)/fisiologia , Valores de Referência , Fatores Sexuais , Tíbia/diagnóstico por imagem , Tíbia/fisiologia , Ultrassonografia/métodos , População UrbanaRESUMO
UNLABELLED: The CAPO Kids trial was a 9-mo, controlled, school-based intervention to examine the effects of a novel, brief, high intensity exercise regime on indices of musculoskeletal and metabolic health in pre- and early-pubertal girls. METHODS: A total of 151 pre- and early-pubertal girls (10.6±0.6years), recruited from two different schools consented to participate; 76 in the exercise group (EX) and 75 in the control group (CON). EX performed 10min bouts of thrice-weekly jumping plus capoeira (a Brazilian sport that combines martial art with dance), along with usual physical education (PE) activities. CON continued usual PE alone. Maturity, weight, height, waist circumference, resting heart rate and blood pressure, maximal vertical jump, and aerobic capacity were determined using standard clinical and field measures. Calcaneal broadband ultrasound attenuation (BUA) and stiffness index (SI) were determined from quantitative ultrasonometry. A subsample of children also underwent DXA and pQCT measures. Prior physical activity participation and daily calcium consumption were determined from validated instruments. RESULTS: EX girls improved BUA more than CON (+4.5% vs. +1.4%, p=0.019). Resting heart rate (-7.2% vs. -1.8%, p<0.01), maximal vertical jump (+13.4% vs. -1.2%, p<0.001), estimated maximal oxygen consumption (+10.6% vs. +1.0%, p<0.001), and waist circumference (+2.7% vs. +5.6%, p<0.001) also improved more for EX than CON. CONCLUSION: Ten minutes of high intensity exercise (capoeira and jumping) three times a week in the primary school setting enhances musculoskeletal and metabolic outcomes in pre- and early-pubertal girls without disrupting the academic schedule. The programme, amenable to broad-scale school implementation, would confer meaningful public health benefits.
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Adiposidade/fisiologia , Osso e Ossos/fisiologia , Exercício Físico/fisiologia , Instituições Acadêmicas , Absorciometria de Fóton , Osso e Ossos/diagnóstico por imagem , Brasil , Criança , Feminino , Fidelidade a Diretrizes , Frequência Cardíaca/fisiologia , Humanos , Estilo de Vida , Oxigênio/metabolismo , Rádio (Anatomia)/diagnóstico por imagem , Rádio (Anatomia)/fisiologia , Descanso/fisiologia , Tíbia/diagnóstico por imagem , Tíbia/fisiologia , Circunferência da Cintura/fisiologiaRESUMO
With the elderly population increase, osteoporosis and its consequences have become not just a health issue but also a serious economic burden. The trabecular bone structure plays a very important role for the bone quality and mechanical competence of the scaffold. Currently, it is claimed that the trabecular microarchitecture understanding can improve the fracture risk prediction above 65%. Several parameters seem to be correlated providing structural details of the trabecular bone network. However, the tortuosity of the trabeculae has not yet been systematically taken into account and its contribution has not been fully investigated and understood. In this paper, we discuss the relationship between the trabecular tortuosity, connectivity, volume fraction, and elasticity, and provide a unified parameter to estimate the mechanical competence of the structure. It is shown that the trabecular network tortuosity presents high linear correlation with the other parameters and that the trabeculae tend to get aligned in the direction where the structure is mostly submitted to stress, corresponding to higher stiffness orientation. This new parameter will help to integrate the relevant information of bone microarchitecture quality and assess more directly the real trabecular fragility in osteoporotic patients.
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Fenômenos Biomecânicos/fisiologia , Imageamento Tridimensional/métodos , Rádio (Anatomia) , Módulo de Elasticidade/fisiologia , Humanos , Análise de Componente Principal , Rádio (Anatomia)/fisiologia , Rádio (Anatomia)/ultraestrutura , Microtomografia por Raio-XRESUMO
UNLABELLED: We examined the association of serum 25-hydroxyvitamin D [25(OH)D] with indices of bone quality in older men. Positive associations for 25(OH)D and bone mineral density, content, cortical thickness, and axial and polar strength strain indices were observed among Caucasians; however, among men of African descent findings were either null or negative. INTRODUCTION: There are limited data on serum 25(OH)D and bone measures in men of African ancestry. To better understand racial differences in vitamin D status and bone health, a cross-sectional study among 446 Caucasian men in the US and 496 men of African ancestry in Tobago (age ≥ 65 years) was conducted. METHODS: Serum 25(OH)D (liquid chromatography and tandem mass spectrometry) was measured, and peripheral quantitative computed tomography scans were administered. Bone measures estimated included trabecular and cortical volumetric bone mineral density (vBMD), bone mineral content (BMC), bone geometry (cross-sectional area and cortical thickness), and polar and axial strength strain indices (SSIp and SSIx). RESULTS: Men of African ancestry had higher 25(OH)D than Caucasians (34.7 vs. 27.6 ng/ml, p < 0.01). Among Caucasians, 25(OH)D was positively (p trend < 0.05) associated with cortical vBMD, total BMC, cortical thickness, SSIp, and SSIx at the distal radius after adjustment for potential confounders. Similar patterns were observed at the distal tibia. In contrast, in men of African ancestry, there was an inverse association (p trend < 0.05) between 25(OH)D and the cross-sectional area, and SSIx. Race modified (p for interaction < 0.05) the association between 25(OH)D and total BMC, cross-sectional area, SSIp, SSIx, and trabecular vBMD of the radius. In men of African ancestry, there was evidence of a threshold effect (at approximately 18 ng/ml) for 25(OH)D on tibial total BMC and cortical thickness. CONCLUSIONS: More studies are needed to better comprehend these race differences for 25(OH)D and bone density, geometry, and indices of bone strength.
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Densidade Óssea/fisiologia , Rádio (Anatomia) , Tíbia , Vitamina D/análogos & derivados , Idoso , População Negra , Estudos Transversais , Humanos , Masculino , Pennsylvania , Rádio (Anatomia)/anatomia & histologia , Rádio (Anatomia)/fisiologia , Tíbia/anatomia & histologia , Tíbia/fisiologia , Trinidad e Tobago/etnologia , Vitamina D/sangue , População BrancaRESUMO
OBJECTIVE: To evaluate the intraobserver and interobserver reliability of radial torsion angle measurement using computed tomography. METHODS: Twelve pairs of cadaver radii and 116 forearms from 58 healthy volunteers were evaluated using axial computed tomography sections measured at the level of the bicipital tuberosity and the subchondral region of the radius. During digital imaging, the angle was formed by two lines, one diametrically perpendicular to the radial tubercle and the other tangential to the volar rim of the distal joint surface. Measurements were performed twice each by three observers. RESULTS: In cadaveric bones, the mean radial torsion angle was 1.48º (-6º - 9º) on the right and 1.62º (-6 º - 8º) on the left, with a mean difference between the right and left sides of 1.61º (0º - 8º). In volunteers, the mean radial torsion angle was 3.00° (-17° - 17°) on the right and 2.91° (-16°- 15°) on the left, with a mean difference between the sides of 1.58º (0º - 7º). There was no significant difference between each side. The interobserver correlation coefficient for the cadaver radii measurements was 0.88 (0.72 - 0.96) and 0.81 (0.58 - 0.93) for the right and left radius, respectively, while for the volunteers, the difference was 0.84 (0.77 - 0.90) and 0.83 (0.75 - 0.89), respectively. Intraobserver reliability was high. CONCLUSION: The described method is reproducible and applicable even when the radial tubercle has a rounded contour.
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Rádio (Anatomia)/diagnóstico por imagem , Rádio (Anatomia)/fisiologia , Adulto , Distribuição por Idade , Idoso , Idoso de 80 Anos ou mais , Cadáver , Intervalos de Confiança , Feminino , Antebraço/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Radiografia , Reprodutibilidade dos Testes , Fatores Sexuais , Estatísticas não Paramétricas , Tomógrafos Computadorizados , Anormalidade Torcional/diagnóstico por imagemRESUMO
OBJECTIVE: To evaluate the intraobserver and interobserver reliability of radial torsion angle measurement using computed tomography. METHODS: Twelve pairs of cadaver radii and 116 forearms from 58 healthy volunteers were evaluated using axial computed tomography sections measured at the level of the bicipital tuberosity and the subchondral region of the radius. During digital imaging, the angle was formed by two lines, one diametrically perpendicular to the radial tubercle and the other tangential to the volar rim of the distal joint surface. Measurements were performed twice each by three observers. RESULTS: In cadaveric bones, the mean radial torsion angle was 1.48º (-6º - 9º) on the right and 1.62º (-6 º - 8º) on the left, with a mean difference between the right and left sides of 1.61º (0º - 8º). In volunteers, the mean radial torsion angle was 3.00° (-17° - 17°) on the right and 2.91° (-16°- 15°) on the left, with a mean difference between the sides of 1.58º (0º - 7º). There was no significant difference between each side. The interobserver correlation coefficient for the cadaver radii measurements was 0.88 (0.72 - 0.96) and 0.81 (0.58 - 0.93) for the right and left radius, respectively, while for the volunteers, the difference was 0.84 (0.77 - 0.90) and 0.83 (0.75 - 0.89), respectively. Intraobserver reliability was high. CONCLUSION: The described method is reproducible and applicable even when the radial tubercle has a rounded contour.