Measuring the dynamic mechanical response of hydrated mouse bone by nanoindentation

This study demonstrates a novel approach to characterizing hydrated bone's viscoelastic behavior at lamellar length scales using dynamic indentation techniques. We studied the submicron-level viscoelastic response of bone tissue from two different inbred mouse strains, A/J and B6, with known differences in whole bone and tissue-level mechanical properties. Our results show that bone having a higher collagen content or a lower mineral-to-matrix ratio demonstrates a trend towards a larger viscoelastic response. When normalized for anatomical location relative to biological growth patterns in the antero-medial (AM) cortex, bone tissue from B6 femora, known to have a lower mineral-to-matrix ratio, is shown to exhibit a significantly higher viscoelastic response compared to A/J tissue. Newer bone regions with a higher collagen content (closer to the endosteal edge of the AM cortex) showed a trend towards a larger viscoelastic response. Our study demonstrates the feasibility of this technique for analyzing local composition-property relationships in bone. Further, this technique of viscoelastic nanoindentation mapping of the bone surface at these submicron length scales is shown to be highly advantageous in studying subsurface features, such as porosity, of wet hydrated biological specimens, which are difficult to identify using other methods. © 2010 Elsevier Ltd.

Polycaprolactone fibres as a potential delivery system for collagen to support bone regeneration

Poly(e-caprolactone) (PCL) is biocompatible, non-immunogenic and non-toxic, and slowly degrades, allowing sufficient time for tissue regeneration. PCL has the potential for application in bone and cartilage repair as it may provide the essential structure required for bone regeneration, however, an ideal scaffold system is still undeveloped. PCL fibres were prepared using the gravity spinning technique, in which collagen was either incorporated into or coated onto the 'as-spun' fibres, in order to develop novel biodegradable polymer fibres which will effectively deliver collagen and support the attachment and proliferation of human osteoblast (HOB) cells for bone regeneration. The physical and mechanical characteristics and cell fibre interactions were analysed. The PCL fibres were found to be highly flexible and inclusion of collagen did not alter the mechanical properties of PCL fibres. Overall, HOB cells were shown to effectively adhere and proliferate on all fibre platforms tested, although proliferation rates were enhanced by surface coating PCL fibres with collagen compared to PCL fibres incorporating collagen and PCL-only fibres. These findings highlight the potential of using gravity spun PCL fibres as a delivery platform for extracellular matrix proteins, such as collagen, in order to enhance cell adherence and proliferation for tissue repair.

Evaluating transglutaminase crosslinked collagen gel systems for hard and soft tissue repair

Tissue Transglutaminase (TG2) and FXIIIa, members of the transglutaminase (TG) family, catalyses a transamidating reaction and form covalent bond between or within proteins. In bone development, both enzymes expressions correlate with the initial of the mineralisation process by osteoblasts and chondrocytes. Exogenous TG2 also promotes maturation of chondrocytes and mineralisation in pre-osteoblasts. To understand the role of endogenous TG2 in osteoblast mineralisation, the TG2 expression was examined during the human osteoblast (HOB) mineralisation. The expression of the endogenous TG2 increased during the mineralisation, yet, its expression was not essential for mineral deposition due to the compensation effect by other members in the TG family. The extracellular transamidating activity of HOBs was found increased during mineralisation and a shift from FXIIIa dominant- to TG2-dominant crosslinking activity was suggested after differentiation. However, the transamidating activity of both TG2 and FXIIIa were not critical for cell mineralisation. On the other hand, Exogenous TG2 was found to enhance wild type HOB and TG2 knockdown HOB mineral deposition. The transamidating activity of TG2 was not required but most likely a close conformation was essential for this enhancement. Results also demonstrated that exogenous TG2 may activate the ß-catenin pathway through LRP5 receptor thus contribute in cell mineralisation. This enhancement could be abolished by addition of ß-catenin inhibitors. Finally, using of TG2 crosslinked collagen gel for bone and cornea repair was evaluated. Crosslinked collagen gel showed promising results in improving HOB mineralisation, human corneal fibroblast (hCF) proliferation and migration. These effects might be resulted from the trapped TG2 within the collagen matrix and the alteration of matrix topography by TG2.

Investigating the role of capacitive coupling between the operating table and the return electrode of an electrosurgery unit in the modification of the current density distribution within the patients’ body

Background: Electrosurgery units are widely employed in modern surgery. Advances in technology have enhanced the safety of these devices, nevertheless, accidental burns are still regularly reported. This study focuses on possible causes of sacral burns as complication of the use of electrosurgery. Burns are caused by local densifications of the current, but the actual pathway of current within patient's body is unknown. Numerical electromagnetic analysis can help in understanding the issue. Methods: To this aim, an accurate heterogeneous model of human body (including seventy-seven different tissues), electrosurgery electrodes, operating table and mattress was build to resemble a typical surgery condition. The patient lays supine on the mattress with the active electrode placed onto the thorax and the return electrode on his back. Common operating frequencies of electrosurgery units were considered. Finite Difference Time Domain electromagnetic analysis was carried out to compute the spatial distribution of current density within the patient's body. A differential analysis by changing the electrical properties of the operating table from a conductor to an insulator was also performed. Results: Results revealed that distributed capacitive coupling between patient body and the conductive operating table offers an alternative path to the electrosurgery current. The patient's anatomy, the positioning and the different electromagnetic properties of tissues promote a densification of the current at the head and sacral region. In particular, high values of current density were located behind the sacral bone and beneath the skin. This did not occur in the case of non-conductive operating table. Conclusion: Results of the simulation highlight the role played from capacitive couplings between the return electrode and the conductive operating table. The concentration of current density may result in an undesired rise in temperature, originating burns in body region far from the electrodes. This outcome is concordant with the type of surgery-related sacral burns reported in literature. Such burns cannot be immediately detected after surgery, but appear later and can be confused with bedsores. In addition, the dosimetric analysis suggests that reducing the capacity coupling between the return electrode and the operating table can decrease or avoid this problem. © 2013 Bifulco et al.; licensee BioMed Central Ltd.

(Table 1) Mineral composition of sand- and silt-sized fractions of bottom sediments from the Romanche Trench

A study was made of mineral composition of sand- and silt-sized fractions of recent clastic (riftogenic) sediments and solidified deposits collected from the bottom of the Romanche Trench during the first voyage of R/V Akademik Kurchatov. Similarity between mineral compositions of sediments and bedrocks (ultrabasites, gabbroids, diabases) was established. This similarity is a basis for considering the mineral complex of the deposits that have been derived from the bedrocks of the trench slopes, and have formed due to their submarine denudation accompanied by tectonic crushing. The same mineral composition was found in pieces of older consolidated deposits; this suggests that conditions of sedimentation similar to those at recent times have existed for a long time in the Romanche Trench.

Location and ages of terrestrial peatlands located on continental shelves and in coastal sediments

This synthesis dataset contains records of freshwater peat and lake sediments from continental shelves and coastal areas. Information included is site location (when available), thickness and description of terrestrial sediments as well as underlying and overlying sediments, dates (when available), and references.

Costs, quality of life and cost-effectiveness of open and arthroscopic repair for rotator cuff tears : economic evaluation alongside the UKUFF trial

FUNDING & ACKNOWLEDGEMENTS This project was funded by the NIHR Health Technology Assessment programme (project number 05/47/02) and is published in full in Health Technology Assessment; Vol. 19, No. 80. Further information available at: http://www.nets.nihr.ac.uk/projects/hta/054702 This paper presents independent research commissioned by the National Institute for Health Research (NIHR). The views and opinions expressed by authors in this publication are those of the authors and do not necessarily reflect those of the NHS, the NIHR, MRC, CCF, NETSCC, the HTA programme or the Department of Health. Due to the confidential nature of the trial data supporting this publication not all of the data can be made accessible to other researchers. Please contact the UKUFF study principal investigator Andrew Carr (andrew.carr@ndorms.ox.ac.uk) for more information. The authors wish to thank the UKUFF trial collaborators for their contribution in managing the conduct of the trial, and for their comments on the interim economic results: Marion Campbell and Hannah Bruhn (Centre for Healthcare Randomised Trials, HSRU, University of Aberdeen), Jonathan Rees MD and David Beard (NDORMS, University of Oxford; NIHR Oxford Biomedical Research Centre), Jane Moser (NDORMS, University of Oxford), Raymond Fitzpatrick and Jill Dawson (NDPH, University of Oxford).

Distribution and Conservation of the Antillean Manatee in Hispaniola

Antillean manatees (Trichechus manatus manatus) were heavily hunted in the past throughout the Wider Caribbean Region (WCR), and are currently listed as endangered on the IUCN Red List of Threatened Species. In most WCR countries, including Haiti and the Dominican Republic, remaining manatee populations are believed to be small and declining, but current information is needed on their status, distribution, and local threats to the species.

To assess the past and current distribution and conservation status of the Antillean manatee in Hispaniola, I conducted a systematic review of documentary archives dating from the pre-Columbian era to 2013. I then surveyed more than 670 artisanal fishers from Haiti and the Dominican Republic in 2013-2014 using a standardized questionnaire. Finally, to identify important areas for manatees in the Dominican Republic, I developed a country-wide ensemble model of manatee distribution, and compared modeled hotspots with those identified by fishers.

Manatees were historically abundant in Hispaniola, but were hunted for their meat and became relatively rare by the end of the 19th century. The use of manatee body parts diversified with time to include their oil, skin, and bones. Traditional uses for folk medicine and handcrafts persist today in coastal communities in the Dominican Republic. Most threats to Antillean manatees in Hispaniola are anthropogenic in nature, and most mortality is caused by fisheries. I estimated a minimum island-wide annual mortality of approximately 20 animals. To understand the impact of this level of mortality, and to provide a baseline for measuring the success of future conservation actions, the Dominican Republic and Haiti should work together to obtain a reliable estimate of the current population size of manatees in Hispaniola.

In Haiti, the survey of fishers showed a wider distribution range of the species than suggested by the documentary archive review: fishers reported recent manatee sightings in seven of nine coastal departments, and three manatee hotspot areas were identified in the north, central, and south coasts. Thus, the contracted manatee distribution range suggested by the documentary archive review likely reflects a lack of research in Haiti. Both the review and the interviews agreed that manatees no longer occupy freshwater habitats in the country. In general, more dedicated manatee studies are needed in Haiti, employing aerial, land, or boat surveys.

In the Dominican Republic, the documentary archive review and the survey of fishers showed that manatees still occur throughout the country, and occasionally occupy freshwater habitats. Monte Cristi province in the north coast, and Barahona province in the south coast, were identified as focal areas. Sighting reports of manatees decreased from Monte Cristi eastwards to the adjacent province in the Dominican Republic, and westwards into Haiti. Along the north coast of Haiti, the number of manatee sighting and capture reports decreased with increasing distance to Monte Cristi province. There was good agreement among the modeled manatee hotspots, hotspots identified by fishers, and hotspots identified during previous dedicated manatee studies. The concordance of these results suggests that the distribution and patterns of habitat use of manatees in the Dominican Republic have not changed dramatically in over 30 years, and that the remaining manatees exhibit some degree of site fidelity. The ensemble modeling approach used in the present study produced accurate and detailed maps of manatee distribution with minimum data requirements. This modeling strategy is replicable and readily transferable to other countries in the Caribbean or elsewhere with limited data on a species of interest.

The intrinsic value of manatees was stronger for artisanal fishers in the Dominican Republic than in Haiti, and most Dominican fishers showed a positive attitude towards manatee conservation. The Dominican Republic is an upper middle income country with a high Human Development Index. It possesses a legal framework that specifically protects manatees, and has a greater number of marine protected areas, more dedicated manatee studies, and more manatee education and awareness campaigns than Haiti. The constant presence of manatees in specific coastal segments of the Dominican Republic, the perceived decline in the number of manatee captures, and a more conservation-minded public, offer hope for manatee conservation, as non-consumptive uses of manatees become more popular. I recommend a series of conservation actions in the Dominican Republic, including: reducing risks to manatees from harmful fishing gear and watercraft at confirmed manatee hotspots; providing alternative economic alternatives for displaced fishers, and developing responsible ecotourism ventures for manatee watching; improving law enforcement to reduce fisheries-related manatee deaths, stop the illegal trade in manatee body parts, and better protect manatee habitat; and continuing education and awareness campaigns for coastal communities near manatee hotspots.

In contrast, most fishers in Haiti continue to value manatees as a source of food and income, and showed a generally negative attitude towards manatee conservation. Haiti is a low income country with a low Human Development Index. Only a single dedicated manatee study has been conducted in Haiti, and manatees are not officially protected. Positive initiatives for manatees in Haiti include: protected areas declared in 2013 and 2014 that enclose two of the manatee hotspots identified in the present study; and local organizations that are currently working on coastal and marine environmental issues, including research and education on marine mammals. Future conservation efforts for manatees in Haiti should focus on addressing poverty and providing viable economic alternatives for coastal communities. I recommend a community partnership approach for manatee conservation, paired with education and awareness campaigns to inform coastal communities about the conservation situation of manatees in Haiti, and to help change their perceived value. Haiti should also provide legal protection for manatees and their habitat.

Sesamoids of the metatarsophalangeal joint of the big toe: a sistematic review

Abstract: The first metatarsal sesamoid bones are not always taken into consideration when making a diagnosis, in pathologies that affect the region of the first metatarsal head. This is due to the insufficient knowledge of all the pathologies that can affect the sesamoids and the relative little incidence that they have. With the increment of sports activities, in particular the running, increasingly affects of the symptoms concerning this region are observed. Methods: A literature search was performed in 5 databases (Medline, PubMed, Scopus, Cochrane Library and BUCEA). The terms included in the search were: sesamoids, anatomy, biomechanics, sesamoids review and sesamoids pathology. In the initial search articles with no more than 10 years, only humans and revision texts are considered. Results: 24 articles were selected and include different pathologies with diagnosis using imaging tests and treatments, both conservative and surgical; as well as aspects from the biomechanics of the metatarsal-sesamoid joint. Conclusion: Sesamoids due of his anatomy, topography and function can be involved in a lot of pathologies; with similar signs and symptoms that can confuse the podiatry when he has to make a correct diagnosis or treatment.

Antimicrobial effect of polymeric biomaterials for bone infection treatment

Dissertação de mestrado em Bioquímica, apresentada à Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2016.

Taxonomy of rare congenital metabolic bone disorders

International audience

Deficiencias minerales en bovinos para carne: diagnóstico, caracterización y control

La demanda de una producción de alimentos cada vez mayor a nivel mundial sumado a la tecnificación y al ritmo acelerado del progreso de las explotaciones agropecuarias actuales hacen que el ganado deba soportar elevadas presiones de producción aumentando los requerimientos de nutrientes. Este es el caso de los minerales considerados actualmente elementos esenciales para los animales, aunque tradicionalmente fueron definidos como los nutrientes pobres de la nutrición y alimentación animal. Actualmente se ha demostrado con evidencia clínica y productiva, el importante rol metabólico de los minerales en el animal sano y productivo, como también se ha definido qué elemento mineral y porcentaje del mismo es requerido para el normal funcionamiento del organismo. Los macro-minerales (calcio, magnesio, fósforo, sodio, potasio, cloro y azufre) y los oligo-minerales (cobre, zinc, hierro, selenio, cobalto, iodo, manganeso, molibdeno y cromo) son elementos esenciales y necesarios para transformar la proteína y la energía de los alimentos en componentes del organismo o en productos animales como leche, carne, crías, piel, lana. Además, ayudan al organismo a combatir las enfermedades, manteniendo al animal en buen estado de salud. Se ha considerado a los minerales como el tercer grupo limitante en la nutrición animal, siendo a su vez, el que mayor potencial y menor costo tiene para incrementar la producción del ganado. Los minerales desempeñan funciones tan importantes como ser constituyentes de la estructura ósea y dental, de tejidos blandos y líquidos corporales. Están involucrados en el funcionamiento celular, siendo activadores de más de trescientas enzimas, constituyentes esenciales de vitaminas, hormonas y pigmentos respiratorios y facilitando la actividad de los microorganismos del rumen. Cuando el aporte de minerales en la ración no es el adecuado en calidad y/o cantidad se originan las deficiencias minerales, encuadradas dentro de las enfermedades metabólicas o enfermedades de la producción. Estas han sido informadas en casi todo el mundo y son responsables de importantes pérdidas económicas en los rodeos de bovinos para carne. Las deficiencias y/o desequilibrios minerales pueden causar los siguientes trastornos en los animales: bajo porcentaje de parición, mayor número de servicios por concepción, abortos, retenciones placentarias, incremento del intervalo entre partos, baja producción de leche, menor peso al nacimiento y al destete, menor porcentaje de destete, menor ganancia de peso, mayor incidencia de enfermedades infecciosas, fracturas espontáneas, diarrea, deformación de huesos y mortandad. Así cobra importancia el diagnóstico mediante el análisis de la sangre de los animales, del pasto y el agua que consumen y la caracterización de estas deficiencias en primarias o secundarias con el objetivo de poder realizar un control de las mismas mediante un adecuado plan de suplementación mineral acorde a las necesidades de los distintos establecimientos agropecuarios.

COMMUNITY KNOWLEDGE, ATTITUDE AND PRACTICES (KAP) ON FLUOROSIS AND ITS MITIGATION IN ENDEMIC AREAS OF ETHIOPIA

Optimum fluoride intake plays an essential role in the prevention of dental caries while fluoride consumption above recommended level interferes with the normal formation of tooth enamel and bones and may increase risk of dental and skeletal fluorosis. The knowledge and practices of endemic communities on etiology of fluorosis will help in its mitigation and prevention. The objective of this study was to investigate the knowledge, attitude and practices of endemic community on fluoride contamination, fluorosis and prevention practices in order to devise coordinated and targeted prevention mechanisms. Focus group discussions (FGD) and key-informant interview were conducted in three dietary areas to collect knowledge, attitude and practices (KAP) of the endemic community in July 2013.The results indicated that health consequences of fluoride contaminated water are fairly understood. None of the discussants mentioned the word “fluoride”. The knowledge and perception of the community on fluoride ingestion is poor. Health extension workers (HEWs) did not teach about fluoride and related health consequences. Dental fluorosis was reported to start at early ages and not commonly perceived as a major problem. However, adolescents worried and felt that they might be singled out when going to other areas. Older people have a skeletal fluorosis, which interferes with their day to day activities. In severely affected people, the teeth were weak and fragile and thus create difficulty in chewing hard foods like unfermented dry flat bread, sugar cane and toasted grains. People prefer rain water rather than water from borehole because of the inconvenient taste of the latter. The endemic communities have no sufficient knowledge and skills on potential sources of fluoride intake, the debilitating effect of high fluoride ingestion, and preventive and mitigatory measures to reduce fluoride intake. The effect of fluoride contamination and mitigatory methods should get sufficient attention by the community, health workers and concerned governmental bodies. The trend of harvesting and using rain water should be encouraged as it reduces fluoride intake. Future studies should focus on information communication on possible fluoride risks, intervention and evaluation studies on defluoridation, rain water harvesting and mitigatory techniques.