Composición corporal y mineral óseo en gimnastas femeninas pre- y peripuberales

La actividad física puede modificar la composición corporal y la mineralización ósea. Se compararon ambas variables en gimnastas femeninas de competición y controles apareados por edad y sexo que realizaban gimnasia recreativa (n = 12 en cada grupo; edades 9 a 14 años). La composición corporal se evaluó por métodos antropométricos y densitometría de rayos X (DXA). El contenido mineral y la densidad mineral óseas se midieron por DXA en cuerpo entero y columna lumbar. La ingesta de calcio se estimó por encuesta.

Body composition in children in remission from acute lymphoblastic leukemia

Background: Changes in body composition are commonly reported in pediatric survivors of acute lymphoblastic leukemia (ALL). However, the effect of ALL and of its treatment on body composition in children in remission from ALL has not been fully examined with the use of a reference method. Objectives: We aimed to determine the body composition and composition of fat-free mass (FFM) in children in remission from ALL. We also aimed to compare the effects that prednisolone and dexamethasone had on the body composition of an ALL survivor population. Design: This cross-sectional study measured height, weight, body volume, total body water, and bone mineral content in 24 children in remission from ALL and 24 age-matched, healthy control subjects. Body composition and FFM composition were evaluated by using the 4-component model. Results: The mean body mass index and fat mass index were significantly (P = 0.05 for both) higher in the ALL survivors than in age-matched control subjects. The composition of the FFM in the 2 treatment groups was not observed to differ significantly. Examination of the composition of FFM made it evident that children in remission from ALL had both significantly greater hydration (P = 0.001) and lower density (P = 0.0001) of FFM than did the control children. Conclusions: Children in remission from ALL may develop excess body fat. To measure body composition accurately in an ALL population, the high hydration and low density of FFM in this population should be taken into consideration.

Efeito da oxigenação hiperbárica no reparo ósseo de ratos diabéticos

The chronic state of hyperglycemia due to diabetes mellitus affects multiples organs impairing life quality. In bone, diabetes alters strength and mineral density and also suppresses the osteoblast activity, leading to an unbalanced bone healing process. Hyperbaric oxygen therapy (HBO) is suggested as an adjuvant treatment to accelerate bone repair. This study evaluated the effects of HBO in the number of mast cells and in new bone formation at the initial stage of bone repair in normoglycemic and diabetic rats. It was hypothesized that HBO treatment may improve bone repair in diabetic bone. The rats were equally divided in four groups: Control (C); Control + HBO (CH); Diabetes (D) and Diabetes + HBO (DH). Diabetes was induced by streptozotocin (65mg/kg) and femoral bone defects were created thirty days after diabetes induction in all groups. HBO initiated immediately after surgery procedure and was performed daily, for 7 days, in the CH e DH groups. Seven days after surgery, all animals were euthanized. The femur diaphyses were removed, fixated, decalcified and processed for paraffin embedding. The semi-serial histological sections obtained were stained with Hematoxylin-Eosin (HE), Mallory Trichrome and Toluidine Blue. The qualitative analysis was conducted in the histology slides stained with HE, where it was evaluated the morphological aspects of bone repair in the lesion area, observing the presence of clot, inflammatory cells, granulation tissue, type of bone tissue, morphology of bone cells, and thickness and organization of bone trabeculae. In the slides stained with Mallory Trichrome and Toluidine Blue were evaluated the percentage of new bone formation and number of mast cells, respectively. The qualitative analysis showed that the CH group presented a more advanced stage of bone repair compared to the C group, showing thicker trabeculae and greater bone filling of the lesion area. In D and DH group, the lesion area was partially filled with new bone formation tissue and presented thinner trabeculae and fewer areas associated to osteoclasts compared to control group. The histomorphometric analysis showed a significant improvement in new bone formation (p<0.001) comparing CH (38.08 ± 4.05) and C (32.05 ± 5.51); C and D (24.62 ± 2.28 and CH and DH (27.14 ± 4.21) groups. In the normoglycemic rats there was a significant increasing in the number of mast cells (p<0.05) comparing C (8.06 ± 5.15) and CH (21.06 ± 4.91) groups. In conclusion, this study showed that diabetes impaired bone repair and HBO was only able to increase new bone formation and the number of mast cells in the normoglycemic animals.

High fat-fed diabetic mice present with profound alterations of the osteocyte network

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Calcium Intake, Major Dietary Sources and Bone Health Indicators in Iranian Primary School Children

Background: Adequate calcium intake may have a crucial role with regards to prevention of many chronic diseases, including hypertension, hypercholesterolemia, different types of cancer, obesity and osteoporosis. In children, sufficient calcium intake is especially important to support the accelerated growth spurt during the preteen and teenage years and to increase bone mineral mass to lay the foundation for older age. Objectives: This study aimed to assess daily calcium intake in school-age children to ensure whether they fulfill the FGP dairy serving recommendations, the recommended levels of daily calcium intake and to assess the relationship between dietary calcium intake and major bone health indicators. Patients and Methods: A total of 501 Iranian school-age children were randomly selected. Calcium intake was assessed using a semi-quantitative food frequency questionnaire. Bone health indicators were also assessed. Results: Dairy products contributed to 69.3% of the total calcium intake of the children. Daily adequate intake of calcium was achieved by 17.8% of children. Only 29.8% met the Food guide pyramid recommendations for dairy intake. Dietary calcium intake was not significantly correlated with serum calcium and other selected biochemical indicators of bone health. Conclusions: The need for planning appropriate nutrition strategies for overcoming inadequate calcium intake in school age children in the city of Tehran is inevitable.

Hormônio de crescimento em crianças e adolescentes com fibrose cística

The recombinant human growth hormone (rhGH) can improve weight gain, physical growth, clinical and lung in cystic fibrosis (CF). However, the routine use, although promising, is not established in the literature. The objective of this study was to assess the benefits of rhGH in children and adolescents with CF. We conducted a systematic review in the database PubMed, Lilacs, SciELO and Cochrane, in the period 2000-2010, using the keywords: cystic fibrosis, growth hormone, children and adolescents. We found 77 articles and included 11 randomized controlled trials, with 290 children and adolescents with CF. The short-term use (1-24 months) of rhGH improved the height, weight, growth rate, bone mineral content and components of pulmonary function. Adverse effects, like diabetes, were not observed in the studies. The short-term use of rhGH improved growth and body composition in patients with CF.

Repair of critical-size defects with autogenous periosteum-derived cells combined with bovine anorganic apatite/collagen: an experimental study in rat calvaria

The aim of this study was to evaluate the bone repair using autogenous periosteum-derived cells (PDC) and bovine anorganic apatite and collagen (HA-COL). PDC from Wistar rats (n=10) were seeded on HA-COL discs and subjected to osteoinduction during 6 days. Critical-size defects in rat calvarias were treated with blood clot (G1), autogenous bone (G2), HA-COL (G3) and HA-COL combined with PDC (G4) (n=40), and then analyzed 1 and 3 months after surgeries. Radiographic analysis exhibited no significant temporal change. G1 and G2 had discrete new marginal bone, but the radiopacity of graft materials in G2, G3 and G4 impaired the detection of osteogenesis. At 3 months, histopathological analysis showed the presence of ossification islets in G1, which was more evident in G2, homogeneous new bone around HA-COL in G3 and heterogeneous new bone around HA-COL in G4 in addition to moderate presence of foreign body cells in G3 and G4. Histomorphometric analysis showed no change in the volume density of xenograft (p>0.05) and bone volume density in G2 was twice greater than in G1 and G4 after 3 months (p<0.05), but similar to G3. The PDC did not increase bone formation in vivo, although the biomaterial alone showed biocompatibility and osteoconduction capacity.

Serum from children with polyarticular juvenile idiopathic arthritis (pJIA) inhibits differentiation, mineralization and may increase apoptosis of human osteoblasts ""in vitro""

We examined the effects of polyarticular juvenile idiopathic arthritis (pJIA) serum on proliferation, differentiation, mineralization, and apoptosis of human osteoblast cells (hOb) in culture. The hOb were cultured with 10% serum from active pJIA and healthy controls (CT) and were tested for DNA synthesis, alkaline phosphatase (AP) activity, osteocalcin (OC) secretion, calcium levels, caspase 3 activity, and DNA fragmentation. None of the patients had used glucocorticoids for at least 1 month before the study, or any other drug that can affect bone mineral metabolism. Human inflammatory cytokine levels (IL-6, IL-8, IL-10, IL-1 beta, TNF-alpha, and IL-12p70) were measured in pJIA and CT sera. Low levels of AP activity was observed in pJIA cultures compared with CT cultures (67.16 +/- 53.35 vs 100.11 +/- 50.64 mu mol p-nitrophenol/h(-1) mg(-1) protein, P=0.008). There was also a significant decrease in OC secretion (9.23 +/- 5.63 vs 12.82 +/- 7.02 ng/mg protein, P=0.012) and calcium levels (0.475 +/- 0.197 vs 0.717 +/- 0.366 mmol/l, P=0.05) in pJIA hOb cultures. No difference was observed in cell proliferation (323.56 +/- 108.23 vs 328.91 +/- 88.03 dpm/mg protein, P=0.788). Osteoblasts cultured with JIA sera showed lower levels of DNA and increased fragmentation than osteoblasts cultured with CT sera. pJIA sera showed higher IL-6 values than CT (21.44 +/- 9.31 vs 3.58 +/- 2.38 pg/ml, P<0.001), but no difference was observed related to IL-8, IL-10, IL-1 beta, TNF-alpha, and IL-12p70 between pJIA and controls. This study suggests that serum from children with pJIA inhibits differentiation, mineralization and may increase apoptosis of hOb cultures, and inflammatory cytokines such as IL-6 might be a mechanism in this find. These results may represent an alternative therapeutic target for prevention and treatment of bone loss in JIA.

Comparative histomorphometric and tomographic analysis of maxillary sinus floor augmentation in rabbits using autografts and xenografts

Our goal was to evaluate bone neoformation promoted by a bovine xenograft composite (XC) compared with autogenous graft for maxillary sinus augmentation in a rabbit model. The left maxillary sinus of 18 male rabbits was filled with 200 mg of cortical and cancellous autogenous bone and the right sinus was filled with 200 mg of a composite comprised organic and inorganic bovine matrices, pool of bBMPs and collagen. Postoperative implant intervals of 2, 4, and 8 weeks were analyzed. Differences in the bone optical density among the groups and experimental periods were evaluated by computed tomography analysis. The tissue response was evaluated by histomorphometric analysis of the newly formed bone, connective tissue and/or granulation tissue, residual material, and bone marrow. The tomographic analyses showed a maximum optical density in the 4-week period for both groups. Histologically, an inflammatory infiltrate was observed at 2 weeks in the XC group but exclusively around the organic particles of the biomaterial. Regarding to the amount of newly formed bone, no statistical differences (p > 0.05) were observed among the two treatments throughout the implant intervals. However, by the end of the 8 weeks, the quantity of bone marrow was two times greater (p < 0.05) in the control group than in the XC group. In conclusion, the xenograft composite promotes formation of new bone in a similar fashion to autogenous bone and could therefore be considered a biomaterial with potential applications as a bone substitute in maxillary sinus floor augmentation. (C) 2007 Wiley Periodicals, Inc.

Timing and magnitude of peak height velocity and peak tissue velocities for early, average, and late maturing boys and girls

Height, weight, and tissue accrual were determined in 60 male and 53 female adolescents measured annually over six years using standard anthropometry and dual-energy X-ray absorptiometry (DXA). Annual velocities were derived, and the ages and magnitudes of peak height and peak tissue velocities were determined using a cubic spline fit to individual data. Individuals were rank ordered on the basis of sex and age at peak height velocity (PHV) and then divided into quartiles: early (lowest quartile), average (middle two quartiles), and late (highest quartile) maturers. Sex- and maturity-related comparisons in ages and magnitudes of peak height and peak tissue velocities were made. Males reached peak velocities significantly later than females for all tissues and had significantly greater magnitudes at peak. The age at PHV was negatively correlated with the magnitude of PHV in both sexes. At a similar maturity point (age at PHV) there were no differences in weight or fat mass among maturity groups in both sexes. Late maturing males, however, accrued more bone mineral and lean mass and were taller at the age of PHV compared to early maturers. Thus, maturational status (early, average, or late maturity) as indicated by age at PHV is inversely related to the magnitude and late maturers for weight and fat mass in boys and girls. Am. J. Hum. Biol. 13:1-8, 2001. (C) 2001 Wiley-Liss, Inc.

Dental Phenotype in Jalili Syndrome Due to a c.1312 dupC Homozygous Mutation in the CNNM4 Gene.

Jalili syndrome denotes a recessively inherited combination of an eye disease (cone-rod dystrophy) and a dental disorder (amelogenesis imperfecta), which is caused by mutations in the CNNM4 gene. Whereas the ophthalmic consequences of these mutations have been studied comprehensively, the dental phenotype has obtained less attention. A defective transport of magnesium ions by the photoreceptors of the retina is assumed to account for the progressive visual impairment. Since magnesium is also incorporated in the mineral of dental hard tissues, we hypothesized that magnesium concentrations in defective enamel resulting from mutations in CNNM4 would be abnormal, if a similar deficiency of magnesium transport also accounted for the amelogenesis imperfecta. Thus, a detailed analysis of the dental hard tissues was performed in two boys of Kosovan origin affected by Jalili syndrome. Retinal dystrophy of the patients was diagnosed by a comprehensive eye examination and full-field electroretinography. A mutational analysis revealed a c.1312 dupC homozygous mutation in CNNM4, a genetic defect which had already been identified in other Kosovan families and putatively results in loss-of-function of the protein. The evaluation of six primary teeth using light and scanning electron microscopy as well as energy-dispersive X-ray spectroscopy showed that dental enamel was thin and deficient in mineral, suggesting a hypoplastic/hypomineralized type of amelogenesis imperfecta. The reduced mineral density of enamel was accompanied by decreased amounts of calcium, but significantly elevated levels of magnesium. In dentin, however, a similar mineral deficiency was associated with reduced magnesium and normal calcium levels. It is concluded that the c.1312 dupC mutation of CNNM4 results in mineralization defects of both enamel and dentin, which are associated with significantly abnormal magnesium concentrations. Thus, we could not disprove the hypothesis that a disrupted magnesium transport is involved in the development of the dental abnormalities observed in Jalili syndrome.

Relationship Between the Development of the Spinal Canal and the Etiopathogenesis of Lumbar Spinal Stenosis

INTRODUCTION: The presence of a pre-existing narrow spinal canal may have an important place in the ethiopathogenesis of lumbar spinal stenosis. By consequence the study of the development of the spinal canal is crucial. The first goal of this work is to do a comprehensive literature search and to give an essential view on the development of spinal canal and its depending factors studied until now. The second goal is to give some considerations and hypothesize new leads for clinically useful researches. MATERIALS AND METHODS: A bibliographical research was executed using different search engines: PubMed, Google Schoolar ©, Ovid ® and Web Of Science ©. Free sources and avaible from the University of Lausanne (UNIL) and Centre Hospitalier Universitaire Vaudois (CHUV) were used. At the end of the bibliographic researches 114 references were found, 85 were free access and just 41 were cited in this work. Most of the found references are in English or in French. RESULTS AND DISCUSSION: The spinal canal is principally limited by the vertebrae which have a mesodermal origin. The nervous (ectodermal) tissue significantly influences the growth of the canal. The most important structure participating in the spinal canal growth is the neurocentral synchondrosis in almost the entire vertebral column. The fusion of the half posterior arches seems to have less importance for the canal size. The growth is not homogeneous but, depends on the vertebral level. Timing, rate and growth potentials differ by regions. Especially in the case of the lumbar segment, there is a craniocaudal tendency which entails a greater post-natal catch-up growth for distal vertebrae. Trefoil-shape of the L5 canal is the consequence of a sagittal growth deficiency. The spinal canal shares some developmental characteristics with different structures and systems, especially with the central nervous system. It may be the consequence of the embryological origin. It is supposed that not all the related structures would be affected by a growth impairment because of the different catch-up potentials. Studies found that narrower spinal canals might be related with cardiovascular and gastrointestinal symptoms, lower thymic function, bone mineral content, dental hypoplasia and Harris' lines. Anthropometric correlations found at birth disappear during the pediatric age. All factors which can affect bone and nervous growth might be relevant. Genetic predispositions are the only factors that can never be changed but the real impact is to ascertain. During the antenatal period, all the elements determining a good supply of blood and oxygen may influence the vertebral canal development, for example smoking during pregnancy. Diet is a crucial factor having an impact on both antenatal and postnatal growth. Proteins intake is the only proved dietetic relationship found in the bibliographic research of this work. The mechanical effects due to locomotion changes are unknown. Socioeconomic situation has an impact on several influencing factors and it is difficult to study it owing to numerous bias. CONCLUSIONS: A correct growth of spinal canal is evidently relevant to prevent not-degenerative stenotic conditions. But a "congenital" narrower canal may aggravate degenerative stenosis. This concerns specific groups of patient. If the size of the canal is highly involved in the pathogenesis of common back pains, a hypothetical measure to prevent developmental impairments could have a not- negligible impact on the society. It would be interesting to study more about dietetic necessities for a good spinal canal development. Understanding the relationship between nervous tissues and vertebra it might be useful in identifying what is needed for the ideal development. Genetic importance and the post-natal influences of upright standing on the canal growth remain unsolved questions. All these tracks may have a double purpose: knowing if it is possible to decrease the incidence of narrower spinal canal and consequently finding possible preventive measures. The development of vertebral canal is a complex subject which ranges over a wide variety of fields. The knowledge of this subject is an indispensable tool to understand and hypothesize the influencing factors that might lead to stenotic conditions. Unfortunately, a lack of information makes difficult to have a complete and satisfactory interdisciplinary vision.

Determinacion de la bioactividad y la resistencia a la compresion de bloques de Poliapatita

Poliapatita® is a composite in study formed by HAP-200®, CaCO3 and POVIAc®. The aims of this work were the determination of the bioactivity and the compression resistance (CR) of biomaterial. The composite was put in contact with a Simulated Body Fluid (28 days at 37 ºC) to evaluate the formation of an superficial apatite layer similar to the bone mineral composition; and to see how diminished the CR in conditions similar to implantation. The bioactivity was evaluated mainly by Scanning Electron Microscopy, Energy-dispersive X-ray Spectroscopy. The composite studied was bioactive and fulfills the requierement of CR asked by ISO 13779-1:2001.

Potential of the Osteoclast’s Proton Pump as a Drug Target in Osteoporosis

Decreasing bone mass during aging predisposes to fractures and it is estimated that every second woman and one in five men will suffer osteoporotic fractures during their lifetime. Bone is an adaptive tissue undergoing continuous remodeling in response to physical and metabolic stimuli. Bone mass decreases through a net negative balance in the bone remodeling process of bone, in which the new bone incompletely replaces the resorbed bone mass. Bone resorption is carried out by the osteoclasts; the bone mineral is solubilized by acidification and the organic matrix is subsequently degraded by proteases. Several classes of drugs are available for prevention of osteoporotic fractures. They act by different mechanisms to increase bone mass, and some of them act mainly as antiresorptives by inhibition of osteoclast formation or their function. Optimally, a drug should act selectively on a specific process, since other processes affected usually result in adverse effects. The purpose of this study was to evaluate whether the osteoclastic vacuolar adenosine trisphosphatases (V-ATPase), which drives the solubilization of bone mineral, can be selectively inhibited despite its ubiquitous cellular functions. The V-ATPase is a multimeric protein composed of 13 subunits of which six possesses two or more isoforms. Selectivity for the osteoclastic V-ATPase could be provided if it has some structural uniqueness, such as a unique isoform combination. The a3 isoform of the 116kDa subunit is inevitable for bone resorption; however, it is also present in, and mainly limited to, the lysosomes of other cells. No evidence of a structural uniqueness of the osteoclastic V-ATPase compared to the lysosomal V-ATPase was found, although this can not yet be excluded. Thus, an inhibitor selective for the a3 isoform would target the lysosomal V-ATPase as well. However, the results suggest that selectivity for bone resorption over lysosomal function can be obtained by two other mechanisms, suggesting that isoform a3 is a valid target. The first is differential compensation; bone resorption depends on the high level of a3 expression, and is not compensated for by other isoforms, while the lower level of a3 in lysosomes of other cells may be partly compensated for. The second mechanism is because the bone resorption process itself is fundamentally different from lysosomal acidification because of the chemistry of bone dissolution and the anatomy of the resorbing osteoclast. By this mechanism, full inhibition of bone resorption is obtained with more than tenfold lower inhibitor concentration than those needed to fully inhibit lysosomal acidification. The two mechanisms are additive. Based on the results, we suggest that bone resorption can be selectively inhibited if VATPase inhibitors that are sufficiently selective for the a3 isoform over the other isoforms are developed.

Effect of metabolic control on parathyroid hormone secretion in diabetic patients

The metabolic derangement caused by diabetes mellitus may potentially affect bone mineral metabolism. In the present study we evaluated the effect of diabetes metabolic control on parathyroid hormone (PTH) secretion during stimulation with EDTA infusion. The study was conducted on 24 individuals, 8 of them normal subjects (group N: glycated hemoglobin - HbA1C = 4.2 ± 0.2%; range = 3.5-5.0%), 8 patients with good and regular metabolic control (group G-R: HbA1C = 7.3 ± 0.4%; range = 6.0-8.5%), and 8 patients with poor metabolic control (group P: HbA1C = 12.5 ± 1.0%; range: 10.0-18.8%). Blood samples were collected at 10-min intervals throughout the study (a basal period of 30 min and a 2-h period of EDTA infusion, 30 mg/kg body weight) and used for the determination of ionized calcium, magnesium, glucose and intact PTH. Basal ionized calcium levels were slightly lower in group P (1.19 ± 0.01 mmol/l) than in group N (1.21 ± 0.01 mmol/l) and group G-R (1.22 ± 0.01 mmol/l). After EDTA infusion, the three groups presented a significant fall in calcium, but with no significant difference among them at any time. Basal magnesium levels and levels determined during EDTA infusion were significantly lower (P<0.01) in group P than in group N. The induction of hypocalcemia caused an elevation in PTH which was similar in groups N and G-R but significantly higher than in group P throughout the infusion period (+110 min, N = 11.9 ± 2.1 vs G-R = 13.7 ± 1.6 vs P = 7.5 ± 0.7 pmol/l; P<0.05 for P vs N and G-R). The present results show that PTH secretion is impaired in patients with poorly controlled diabetes.