940 resultados para volumetric bone mineral density


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Consumption of low-fat milk (LFM) after resistance training has been shown to have positive influences on body composition and training adaptations; however, little research has examined the effects of LFM consumption following endurance training. The purpose of the study was to look at the effects of combining additional servings of LFM following endurance exercise on body composition, bone health, and training adaptations. 40 healthy males were recruited. Individuals were randomized into 4 groups – DEI (750mL LFM immediately post exercise), DEA (750mL LFM 4 hrs prior to or 6 hrs post exercise), CEI (750mL carbohydrate beverage immediately post-exercise), and CEA (750mL carbohydrate beverage immediately post-exercise). Participants took part in a 12-week endurance training intervention (1 h/day, 3 d/wk, ~60% max HR). 22 participants completed the study. Analysis showed significant increases in lean mass, spinal bone mineral content, relative VO2peak, and a decrease in Trap 5β across all groups (p < 0.05).

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This study compares associations between demographic profiles, long bone lengths, bone mineral content, and frequencies of stress indicators in the preadult populations of two medieval skeletal assemblages from Denmark. One is from a leprosarium, and thus probably represents a disadvantaged group (Naestved). The other comes from a normal, and in comparison rather privileged, medieval community (AEbelholt). Previous studies of the adult population indicated differences between the two skeletal collections with regard to mortality, dental size, and metabolic and specific infectious disease. The two samples were analyzed against the view known as the "osteological paradox" (Wood et al. [1992] Curr. Anthropol. 33:343-370), according to which skeletons displaying pathological modification are likely to represent the healthier individuals of a population, whereas those without lesions would have died without acquiring modifications as a result of a depressed immune response. Results reveal that older age groups among the preadults from Naestved are shorter and have less bone mineral content than their peers from AEbelholt. On average, the Naestved children have a higher prevalence of stress indicators, and in some cases display skeletal signs of leprosy. This is likely a result of the combination of compromised health and social disadvantage, thus supporting a more traditional interpretation. The study provides insights into the health of children from two different biocultural settings of medieval Danish society and illustrates the importance of comparing samples of single age groups.

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Background: Physical and bioceramic incorporation surface treatments at the nanometer scale showed higher means of bone-to-implant contact (BIC) and torque values compared with surface topography at the micrometer scale; however, the literature concerning the effect of nanometer scale parameters is sparse. Purpose: The aim of this study was to evaluate the influence of two different implant surfaces on the percentage bone-to-implant contact (BIC%) and bone osteocyte density in the human posterior maxilla after 2 months of unloaded healing. Materials and Methods: The implants utilized presented dual acid-etched (DAE) surface and a bioceramic molecular impregnated treatment (Ossean(R), Intra-Lock International, Boca Raton, FL, USA) serving as control and test, respectively. Ten subjects (59 1 9 years of age) received two implants (one of each surface) during conventional implant surgery in the posterior maxilla. After the non-loaded period of 2 months, the implants and the surrounding tissue were removed by means of a trephine and were non-decalcified processed for ground sectioning and analysis of BIC%, bone density in threaded area (BA%), and osteocyte index (Oi). Results: Two DAE implants were found to be clinically unstable at time of retrieval. Histometric evaluation showed significantly higher BIC% and Oi for the test compared to the control surface (p < .05), and that BA% was not significantly different between groups. Wilcoxon matched pairs test was used to compare the differences of histomorphometric variables between implant surfaces. The significance test was conducted at a 5% level of significance. Conclusion: The histological data suggest that the bioceramic molecular impregnated surface-treated implants positively modulated bone healing at early implantation times compared to the DAE surface.

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Combining exercise with calcium supplementation may produce additive or multiplicative effects at loaded sites; thus, we conducted a single blind, prospective, randomized controlled study in pre- and early-pubertal girls to test the following hypotheses. (1) At the loaded sites, exercise and calcium will produce greater benefits than exercise or calcium alone. (2) At non-loaded sites, exercise will have no benefit, whereas calcium with or without exercise will increase bone mass over that in exercise alone or no intervention. Sixty-six girls aged 8.8 ± 0.1 years were randomly assigned to one of four study groups: moderate-impact exercise with or without calcium or low-impact exercise with or without calcium. All participants exercised for 20 minutes, three times a week and received Ca-fortified (434 ± 19 mg/day) or non-fortified foods for 8.5 months. Analysis of covariance (ANCOVA) was used to determine interaction and main effects for exercise and calcium on bone mass after adjusting for baseline bone mineral content and growth in limb lengths. An exercise-calcium interaction was detected at the femur (7.1%, p < 0.05). In contrast, there was no exercise-calcium interaction detected at the tibia-fibula; however, there was a main effect of exercise: bone mineral content increased 3% more in the exercise than non-exercise groups (p < 0.05). Bone mineral content increased 2-4% more in the calcium-supplemented groups than the non-supplemented groups at the humerus (12.0% vs. 9.8%, respectively, p < 0.09) and radius-ulna (12.6% vs. 8.6%, respectively, p < 0.01). In conclusion, greater gains in bone mass at loaded sites may be achieved when short bouts of moderate exercise are combined with increased dietary calcium, the former conferring region-specific effects and the latter producing generalized effects.

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Objective: To assess the influence of body build on the bias and limits of agreement for estimates of body fat obtained from anthropometric prediction equations when compared with the same data obtained by dual energy X-ray absorptiometry (DEXA).

Survey design and subjects:
Ninety-one premenopausal women, aged between 20 and 54 years, were chosen to represent a range of skeletal body build (relative silting height 0.50-0.56) and body fatness [body mass index (BMI) 18-34 kg/m2]. Measurements of weight, sitting height, stature, skinfold thickness, waist, umbilical and hip circumference and total body resistance and reactance were made on all subjects by standard techniques after an overnight fast. A DEXA measurement of total body fat, fat-free soft tissue and total body bone mineral mass was also obtained within 2 weeks of the anthropometric assessment.

Results:
At the group level the mean difference (bias) between DEXA and the anthropometric estimates of body fat was similar for all three anthropometric estimates ranging from 2.7 kg with impedance to 1.8 kg with skinfold thickness. The 95% limits of agreement were also similar, ranging from ±5.3 kg with body mass index to ±4.1 kg with impedance. Umbilical circumference, BMI and the amount of bone mineral expressed as a proportion of the fat-free soft-tissue mass were all significantly (P < 0.01) correlated with the level of bias between DEXA and the anthropometric estimates of body fat. This was not the case for relative sitting height or measures of body fat distribution. Regression equations which included BMI or umbilical circumference in combination with the predicted estimates of body fat essentially eliminated the association between the level of bias in predicted body fat and the level of body fatness. They also reduced the 95% limits of agreement between DEXA and the anthropometric estimates of body fat.

Conclusions:
Using DEXA estimates of body fat as the standard of reference our results suggest that the comparability and precision of body fat estimates derived from age- and/or sex-specific anthropometric prediction equations based on skinfolds and BMI, but not impedance, can be improved by adjusting for differences in BMI and umbilical circumference respectively.

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The effects of serum and brain calcium concentration on rat behavior were tested by maintaining animals on either distilled water (N = 60) or water containing 1% calcium gluconate (N = 60) for 3 days. Animals that were maintained on high calcium drinking water presented increased serum calcium levels (control = 10.12 ± 0.46 vs calcium treated = 11.62 ± 0.51 µg/dl). Increase of brain calcium levels was not statistically significant. In the behavioral experiments each rat was used for only one test. Rats that were maintained on high calcium drinking water showed increased open-field behavior of ambulation (20.68%) and rearing (64.57%). on the hole-board, calcium-supplemented animals showed increased head-dip (67%) and head-dipping (126%), suggesting increased ambulatory and exploratory behavior. The time of social interaction was normal in animals maintained on drinking water containing added calcium. Rats supplemented with calcium and submitted to elevated plus-maze tests showed a normal status of anxiety and elevated locomotor activity. We conclude that elevated levels of calcium enhance motor and exploratory behavior of rats without inducing other behavioral alterations. These data suggest the need for a more detailed analysis of several current proposals for the use of calcium therapy in humans, for example in altered blood pressure states, bone mineral metabolism disorders in the elderly, hypocalcemic states, and athletic activities.

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A diminuição da densidade mineral óssea das vértebras, própria do processo de envelhecimento e que pode ser agravada pela osteoporose, determina uma diminuição da região anterior dos corpos vertebrais, resultando em compressão e colapso dessas vértebras, com maior estreitamento dos discos e espaços intervertebrais. Essas novas condições interferem no funcionamento normal de órgãos e sistemas do organismo. O objetivo foi avaliar o grau de cifose torácica e a capacidade funcional de mulheres idosas com e sem osteoporose. Foram avaliadas 30 idosas ativas fisicamente, sendo 20 sem osteoporose ( GSO: 65,1± 4,67 anos) e 10 idosas com osteoporose (GCO: 68,6± 6,46anos). Foram avaliados a medida da cifose torácica, teste de caminhada de seis minutos (TC6'), Timed Up and go (TUG) e força dos músculos respiratórios (PImáx e PEmáx). Os dados obtidos foram analisados utilizando o teste t de Student. O nível de significância utilizado foi de 5% (α£ 0,05). Houve diferença significativa entre os grupos sem (GSO) e com osteoporose (GCO) somente no TC6'(GSO: 426,63±46,36 m; GCO: 392,64±36,68 m , α =0,02). As outras variáveis analisadas não apresentaram diferença significativa (Cifose torácica: α = 0,17; TUG: α =0,49; PImax: α =0,45; PEmax: α =0,19). A osteoporose não influenciou o grau de cifose torácica, a força dos músculos respiratórios e mobilidade das idosas. Entretanto, o desempenho no TC6' foi influenciado negativamente pela osteoporose.

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Purpose: the effect of orthodontic movement on the periodontal tissues of maxillary second pre-molars, after regenerative treatment for class II furcations, was evaluated in four mongrel dogs.Material and Methods: Class II furcation lesions were created. After 75 days they were treated with bovine bone mineral matrix and guided tissue regeneration with absorbable membrane. After 2 months of daily plaque control, each of the dog's furcation pre-molars was randomly assigned to a test or control group. Orthodontic appliances were placed on both sides of the maxilla using third pre-molars and canines as anchorages. In the test group, bodily orthodontic movement of the second pre-molars was performed in the mesial direction for 3 months while control pre-molars remained unmoved. The dogs were sacrificed for histometric and histologic analyses.Results: There were no statistically significant differences between the two groups in total bone and biomaterial areas or linear extension of periodontal regeneration on the radicular surfaces. In the test group, however, there was a tendency to a greater quantity of bone and a lesser quantity of biomaterial.Conclusion: the orthodontic movement was not pre-judicial to the results obtained with the regenerative periodontal treatment.

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Background:Bone graft procedures have been used commonly in buco-maxillo-facial surgery. For this reason, many researchers have evaluated the bone substitutes.Purpose:The present study evaluated soft and hard tissue reactions to two different hydroxyapatites HAs (synthetic HA and natural HA) and bioactive glass implanted into the sockets immediately after extraction.Materials and Methods:First and third upper and lower premolars, on both sides, were extracted from six female dogs. The alveolar sockets were randomly assigned to four groups: Group 1 - control (unfilled), Group 2 - filled with synthetic hydroxyapatite, Group 3 - filled with bovine bone mineral (natural HA), and Group 4 - filled with bioactive glass. The animals were euthanized at 4 weeks (n = 2), 8 weeks (n = 2), and 28 weeks (n = 2) after extraction. The mandible and maxilla of each animal were removed for histological analysis to determine soft tissue reactions, newly formed bone, bone characteristics, and presence or absence of implanted materials.Results:Most particles of synthetic hydroxyapatite had bone formation on their surface, although some particles showed a layer of fibrous connective tissue. The bovine bone mineral group exhibited particles partially replaced with bone formation. The bioactive glass group showed particles with a thin layer of calcified tissue, but was absent in some specimens, suggesting complete resorption.Conclusion:All biomaterials had similar behavior. Bovine bone mineral, compared to synthetic hydroxyapatite and bioactive glass, showed a larger number of particles covered with osseous tissue. All biomaterials interfered with the socket repair process.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The shrinking behavior, apparent densities and rehydration indexes of fresh and osmotically pre-treated pineapple slices during air-drying were obtained. The air drying velocity varied from 1.5 to 2.5 m/s and the air temperature from 40 to 70 degreesC. By means of automatic control, it was possible to obtain drying curves under conditions of constant product temperature. Volumetric shrinkage of fresh samples was temperature independent for drying at high air velocities but, at lower velocities, increased with decreasing drying temperature. Osmotically pre-treating the material resulted in reduced shrinkage, as well as drying with product temperature controlled, due to lower drying times needed that led to shorter high temperature exposition. Moisture dependence of apparent density was highly non-linear and could be fitted by an empirical model. Fresh sample rehydration indexes were higher than osmosed ones and increased with increasing temperature, except for pre-treated samples dried at 70 degreesC, probably due to superficial sugar caramelization, which reduced surface water permeability.

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The objective of this work was to evaluate the effect of Ca: available P (P-a) ratio in the diets on performance and bone mineral depositions of juvenile Nile tilapia (2.5 +/- 0.5g). Seven isoproteic and isoenergetic diets (28% CP and 3100 Kcal of DE/Kg of diet), with similar crude fiber and sulfur aminoacids content, were used. The diets had 0.50 and 0.25; 0.50 and 0.50; 0.50 and 0.75; 0.80 and 0.40; 0.80 and 0.80; and 0.80 and 1.20% of Ca and P-a which corresponded to Ca/P-a ratios of 2:1;1:1 and 1:1.5, respectively. An additional control diet, with low levels of Ca and Pa (0.02 and 0.12%, respectively) was used. A completely randomized design with a 2'3 factorial arrangement (Ca level and Ca:P-a ratio) on treatments, plus the additional control diet and three replications was used. Five fishes per aquaria were randomly allotted to 21 fiberglass aquaria (80L). The temperature of the water was maintained close to 26degreesC, and the oxygen, pH and ammonia levels of the water were monitored. The results showed that it was necessary a minimum dietary level of 0.25% of P-a for a satisfactory bone mineral depositions, and that the best performance results were achieved using diets with Ca: P-a ratios between 1:1 and 1:1.5.