1,056 research outputs found

    Bone resorption and formation in the pedicles of European roe deer (Capreolus capreolus) in relation to the antler cycle—A morphological and microanalytical study

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    We analyzed pedicle bone from roe bucks that had died around antler casting or shortly before or during the rutting period. Pedicles obtained around antler casting were highly porous and showed signs of intense osteoclastic activity that had caused the formation of an abscission line. Following the detachment of the antler plus a portion of pedicle bone, osteoclastic activity in the pedicles continued for some time, and new bone was deposited onto the separation plane of the pedicle stump, leading to partial pedicle restoration. Pedicles obtained around the rutting period were compact structures. The newly formed, often very large secondary osteons, which had filled the resorption cavities, exhibited a lower mineral density than the persisting older bone. The middle zones of the lamellar infilling frequently showed hypomineralized lamellae and enlarged osteocyte lacunae. This indicates a deficiency in mineral elements during the formation of these zones that occurred along with peak antler mineralization. We suggest that growing antlers and compacting pedicles compete for mineral elements, with the rapidly growing antlers being the more effective sinks. The competition between the two simultaneously mineralizing structures is probably more severe in Capreolus capreolus than in other cervids. This is because roe bucks regrow their antlers during late autumn and winter, a period of limited food and associated mineral supply. The pedicle is a heavily remodeled bone structure with distinct seasonal variation in porosity. Pedicle remodeling differs in several aspects from the normal bone remodeling process in the mammalian skeleton.18 página

    Distribution, structure, and mineralization of calcified cartilage remnants in hard antlers

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    Antlers are paired deciduous bony cranial appendages of deer that undergo a regular cycle of growth, death and casting, and constitute the most rapidly growing bones in mammals. Antler growth occurs in an appositional mode and involves a modified form of endochondral ossification. In endochondral bones, calcified cartilage is typically a transient tissue that is eventually completely replaced by bone tissue. We studied the distribution and characteristics of calcified cartilage in hard antlers from three deer species (Capreolus capreolus, Cervus elaphus, Dama dama), i.e., in antlers from which the skin (velvet) had been shed. Remnants of calcified cartilage were regularly present as part of the trabecular framework in the late formed, distal antler portions in all three species, whereas this tissue was largely or completely missing in the more proximal antler portions. The presence of calcified cartilage remnants in the distal antler portions is attributed to the limited antler lifespan of only a few months, which is also the reason for the virtual lack of bone remodeling in antlers. The calcified cartilage matrix was more highly mineralized than the antler bone matrix. Mineralized deposits were observed in some chondrocyte lacunae and occasionally also in osteocyte lacunae, a phenomenon that has not previously been reported in antlers. Using synchrotron radiation-induced X-ray fluorescence (SR-XRF) mapping, we further demonstrated increased zinc concentrations in cement lines, along the inner borders of incompletely formed primary osteons, along the walls of partly or completely mineral-occluded chondrocyte and osteocyte lacunae, and in intralacunar mineralized deposits. The present study demonstrates that antlers are a promising model for studying the mineralization of cartilage and bone matrices and the formation of mineralized deposits in chondrocyte and osteocyte lacunae

    Spherical deconvolution of multichannel diffusion MRI data with non-Gaussian noise models and spatial regularization

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    Spherical deconvolution (SD) methods are widely used to estimate the intra-voxel white-matter fiber orientations from diffusion MRI data. However, while some of these methods assume a zero-mean Gaussian distribution for the underlying noise, its real distribution is known to be non-Gaussian and to depend on the methodology used to combine multichannel signals. Indeed, the two prevailing methods for multichannel signal combination lead to Rician and noncentral Chi noise distributions. Here we develop a Robust and Unbiased Model-BAsed Spherical Deconvolution (RUMBA-SD) technique, intended to deal with realistic MRI noise, based on a Richardson-Lucy (RL) algorithm adapted to Rician and noncentral Chi likelihood models. To quantify the benefits of using proper noise models, RUMBA-SD was compared with dRL-SD, a well-established method based on the RL algorithm for Gaussian noise. Another aim of the study was to quantify the impact of including a total variation (TV) spatial regularization term in the estimation framework. To do this, we developed TV spatially-regularized versions of both RUMBA-SD and dRL-SD algorithms. The evaluation was performed by comparing various quality metrics on 132 three-dimensional synthetic phantoms involving different inter-fiber angles and volume fractions, which were contaminated with noise mimicking patterns generated by data processing in multichannel scanners. The results demonstrate that the inclusion of proper likelihood models leads to an increased ability to resolve fiber crossings with smaller inter-fiber angles and to better detect non-dominant fibers. The inclusion of TV regularization dramatically improved the resolution power of both techniques. The above findings were also verified in brain data

    Manganese supplementation in deer under balanced diet increases impact energy and contents in minerals of antler bone tissue

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    Bone ash, collagen, Ca and P composition, are considered the main factors affecting mechanical properties in bones. However, a series of studies in bone and antler have shown that some trace minerals, such as manganese, may play a role whose importance exceeds what may be expected considering their low content. A previous study showed that a reduction in manganese in antlers during a year of late winter frosts led to generalized antler breakage in Spain, which included a reduction of 30% of cortical thickness, 27% reduction in impact energy, and 10% reduction in work to peak force. Starting for this observation, we experimentally studied the effects of manganese supplementation in adults and yearling (yearlings) red deer under a balanced diet. Subjects were 29 deer of different age classes (adult n = 19, yearlings n = 10) that were divided in a manganese injected group (n = 14) and a control group (n = 15). Antler content in ashes and minerals, intrinsic mechanical properties and cross section structure were examined at 4 points along the antler beam. A one way ANOVA (mean per antler) showed that in yearlings, manganese supplementation only increased its content and that of Fe. However, in adults, Mn supplementation increased the mean content per antler of Ca, Na, P, B, Co, Cu, K, Mn, Ni, Se (while Si content was reduced), and impact work but not Young's modulus of elasticity, bending strength or work to peak force. A GLM series on characteristics in the uppermost part examined in the antler, often showing physiological exhaustion and depletion of body stores, showed also a 16% increase in work to peak force in the antlers of the treated group. Thus, manganese supplementation altered mineral composition of antler and improved structure and some mechanical properties despite animals having a balanced diet.Funding was provided by Ministerio de Economía y Competitividad, Government of Spain (MINECO): Project AGL2012-38898 to TLC, AG, LG, FC, JC; Consejería de Educación y Deportes de Castilla-La Mancha: Project PEII-2014-004-P to LG TLC AG.Peer Reviewe

    Effect of gingival application of melatonin on alkaline and acid phosphatase, osteopontin and osteocalcin in patients with diabetes and periodontal disease

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    Objectives: To assess the effect of topical application of melatonin to the gingiva on salivary fluid concentrations of acid phosphatase, alkaline phosphatase, osteopontin, and osteocalcin. Study Design: Cross-sectional study of 30 patients with diabetes and periodontal disease and 30 healthy subjects. Diabetic patients were treated with topical application of melatonin (1% orabase cream formula) once daily for 20 days and controls with a placebo formulation. Results: Before treatment with melatonin, diabetic patients showed significantly higher mean salivary levels of alkaline and acid phosphatase, osteopontin and osteocalcin than healthy subjects (P < 0.01). After treatment with melatonin, there was a statistically significant decrease of the gingival index (15.84± 10.3 vs 5.6 ± 5.1) and pocket depth (28.3 ± 19.5 vs 11.9 ± 9.0) (P < 0.001). Also, use of melatonin was associated with a significant reduction of the four biomarkers. Changes of salivary acid phosphatase and osteopontin correlated significantly with changes in the gingival index, whereas changes of alkaline phosphatase and osteopontin correlated significantly with changes in the pocket depth. Conclusions: Treatment with topical melatonin was associated with an improvement in the gingival index and pocket depth, a reduction in salivary concentrations of acid phosphatase, alkaline phosphatase, osteopontin and osteocalcin

    Primeros estudios paleohistológicos sobre fósiles de vertebrados en el Perú: metodología y resultados preliminares

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    Actualmente la paleohistología es usada para efectuar diferentes tipos de inferencias paleobiológicas tales como: el estudio de tasas de crecimiento en los vertebrados, adaptaciones acuáticas de los huesos (ej. paquiostosis), desarrollo y efectos de patologías, etc. En este artículo se presentan los primeros resultados sobre la implementación de protocolos paleohistológicos en el Instituto Geológico, Minero y Metalúrgico como parte del convenio de colaboración con el Museo de Historia Natural de la Universidad Nacional Mayor de San Marcos

    An overview of offshore wind energy resources in Europe under present and future climate

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    Long-term sustainable development of European offshore wind energy requires knowledge of the best places for installing offshore wind farms. To achieve this, a good knowledge of wind resources is needed, as well as knowledge of international, European, and national regulations regarding conflict management, marine environment conservation, biodiversity protection, licensing processes, and support regimes. Such a multidisciplinary approach could help to identify areas where wind resources are abundant and where conflicts with other interests are scarce, support measures are greater, and licensing processes are streamlined. An overview of offshore wind power studies at present, and of their future projections for the 21st century, allows for determining the optimal European locations to install or maintain offshore wind farms. Only northern Europe, the northwest portion of the Iberian Peninsula, the Gulf of Lyon, the Strait of Gibraltar, and the northwest coast of Turkey show no change or increase in wind power, revealing these locations as the most suitable for installing and maintaining offshore wind farms in the future. The installation of wind farms is subject to restrictions established under international law, European law, and the domestic legal framework of each EU member state. Europe is moving toward streamlining of licensing procedures, reducing subsidies, and implementing auction systems.Xunta de Galicia | Ref. ED431C 2017/64Xunta de Galicia | Ref. ED481A-2016/36Fundação para a Ciência e a Tecnologia | Ref. SFRH/BPD/118142/20

    Molecular Mechanisms in Fetal Myocardial Affection Induced by Gestational Diabetes Mellitus: A Literature Review

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    Introducción: La Diabetes Mellitus Gestacional (DMG) es una condición metabólica compleja que afecta la salud materna y fetal, la cuál a incrementado su diagnóstico en los últimos años. Se ha asociado con anomalías cardiacas fetales (ACF), por lo que es fundamenteal conocer las bases moleculares de su desarrollo. Objetivo: Analizar literatura científica actual, para identificar mecanismos y vías moleculares clave implicados en la afección miocárdica fetal. Metodología: Consulta de bases de datos Pubmed, Scopus y Web of Science. Las publicaciones consideradas fueron del periodo 2019-2024 y excluyendo artículos que analizaran alteraciones cardíacas fetales no relacionadas con DMG. Resultados: Se reconocieron genes, mecanismos y vías moleculares, así como mecanismos clave en la morfogénesis cardíaca, particularmente vías relacionadas con la hiperglucemia e hiperinsulinemia, desregulación de factores de crecimiento, de genes encargados del desarrollo miocárdico, que conducen a ACF.Conclusión: La hiperglucemia e hiperinsulinemia materna y fetal, conducen a modificación de la expresión de genes y crecimiento celular miocárdico en la ACF&nbsp; asociada con DMG.Introduction: Gestational Diabetes Mellitus (GDM) is a complex metabolic condition that affects maternal and fetal health, particularly associated with functional anomalies in the fetal myocardium. This has increased interest in understanding the molecular bases of the condition. Objective: To analyze the current scientific literature to identify key molecular mechanisms involved in fetal myocardial affection. Methodology: PubMed, Scopus, and Web of Science databases were consulted, considering publications from the period 2019-2024. Articles addressing fetal cardiac complications unrelated to GDM were excluded. Results: Key molecular mechanisms in cardiac morphogenesis were identified, particularly pathways related to maternal and fetal hyperglycemia and hyperinsulinemia, such as mTOR, AKT, ERK, overexpression of TNNI3K and PK2M, deregulation of factors like IGF-1, TGFβ1, and Wnt/β-catenin, as well as increased reactive oxygen species (ROS) leading to cardiac hypertrophy. Conclusion: The results indicate that maternal hyperglycemia and hyperinsulinemia induce modifications in gene expression and abnormal fetal myocardial cell growth in relation to GDM, with preventive and therapeutic implications

    Evolution of soil organic carbon during a chronosequence of transformation from cacao (Theobroma cacao l.) plantation to grassland

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    The aim of this research was to evaluate the impact of the soil use change of the Cocoa Agroforestry System (CAS) on soil organic carbon (SOC) levels and other indicating soil chemical fertility properties (apparent density ρb, cation exchange capacity CEC, total soil N TSN), when a soil use change occurs from CAS to grassland (GL). For this, in order to be selected was recorded, considering different time intervals (1-5, 6-10 y 11-20 years). However, a CAS of 20-35 years was considered as a reference. In addition, soil samples were taken at -30 cm depth to determine the contents of SOC, TSN, CEC, ρb, soil organic matter (SOM) and the soil C/N relationship. Consequently, an in situ resistance to soil penetration was evaluated. The results indicated the change in soil use from CAS to GL, did not cause a significant decrease in the amount of stored SOC (0-30 cm) during the considered time with respect to CAS. However, if only the first -10 cm of soil is sampled, a significant soil compaction is observed throughout a decrease in the CEC value in the long term (20 years)
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