Type I Collagen and Strontium-Containing Mesoporous Glass Particles as Hybrid Material for 3D Printing of Bone-Like Materials

Bone tissue engineering offers an alternative promising solution to treat a large number of bone injuries with special focus on pathological conditions, such as osteoporosis. In this scenario, the bone tissue regeneration may be promoted using bioactive and biomimetic materials able to direct cell response, while the desired scaffold architecture can be tailored by means of 3D printing technologies. In this context, our study aimed to develop a hybrid bioactive material suitable for 3D printing of scaffolds mimicking the natural composition and structure of healthy bone. Type I collagen and strontium-containing mesoporous bioactive glasses were combined to obtain suspensions able to perform a sol-gel transition under physiological conditions. Field emission scanning electron microscopy (FESEM) analyses confirmed the formation of fibrous nanostructures homogeneously embedding inorganic particles, whereas bioactivity studies demonstrated the large calcium phosphate deposition. The high-water content promoted the strontium ion release from the embedded glass particles, potentially enhancing the osteogenic behaviour of the composite. Furthermore, the suspension printability was assessed by means of rheological studies and preliminary extrusion tests, showing shear thinning and fast material recovery upon deposition. In conclusion, the reported results suggest that promising hybrid systems suitable for 3D printing of bioactive scaffolds for bone tissue engineering have been developed

Future directions for the management of pain in osteoarthritis.

Osteoarthritis (OA) is the predominant form of arthritis worldwide, resulting in a high degree of functional impairment and reduced quality of life owing to chronic pain. To date, there are no treatments that are known to modify disease progression of OA in the long term. Current treatments are largely based on the modulation of pain, including NSAIDs, opiates and, more recently, centrally acting pharmacotherapies to avert pain. This review will focus on the rationale for new avenues in pain modulation, including inhibition with anti-NGF antibodies and centrally acting analgesics. The authors also consider the potential for structure modification in cartilage/bone using growth factors and stem cell therapies. The possible mismatch between structural change and pain perception will also be discussed, introducing recent techniques that may assist in improved patient phenotyping of pain subsets in OA. Such developments could help further stratify subgroups and treatments for people with OA in future

Study on the role of calcium in photosynthetic oxygen evolution

Three extrinsic polypeptides of molecular mass 17, 23, 33 kDa and 4 manganese ions associated with photosystem II are involved in the oxygen evolution process. Calcium and chloride ions are essential for oxygen evolution. If the 17 and 23 kDa polypeptides are depleted, mM concentrations of both ions have to be supplied for maximum oxygen evolution. The depletion of calcium ions from preparations of oxygen evolving photosystem 2 was investigated. Calcium ions were found to be accessible to depletion when the 17 and 23 kDa polypeptides were depleted. Calcium depletion was monitored by observing the S2 state multiline epr signal and measuring the rate of oxygen evolution. Calcium appeared to play an essential role in oxygen evolution. Strontium and vanadyl ions were the only divalent cations that partially replaced the role of calcium. When calcium ions were depleted in the S0 state there was no formation of the S2 state multiline epr signal and oxygen evolution was inhibited. Other calcium depletion methods inhibited oxygen evolution, but did not inhibit the formation of the S2 state multiline epr signal. The role of the tyrosine D in oxygen evolution and the effect of calcium depletion on this component was investigated. D was found to have a role in reseting the oxygen evolving complex to the S1 state in the dark. This did not occur after calcium depletion in the S0 state

3d printing in alginic acid bath of in-situ crosslinked collagen composite scaffolds

Bone-tissue regeneration is a growing field, where nanostructured-bioactive materials are designed to replicate the natural properties of the target tissue, and then are processed with technolo-gies such as 3D printing, into constructs that mimic its natural architecture. Type I bovine collagen formulations, containing functional nanoparticles (enriched with therapeutic ions or biomolecules) or nanohydroxyapatite, are considered highly promising, and can be printed using support baths. These baths ensure an accurate deposition of the material, nonetheless their full removal post-printing can be difficult, in addition to undesired reactions with the crosslinking agents often used to improve the final structural integrity of the scaffolds. Such issues lead to partial collapse of the printed constructs and loss of geometrical definition. To overcome these limitations, this work presents a new alternative approach, which consists of adding a suitable concentration of crosslinking agent to the printing formulations to promote the in-situ crosslinking of the constructs prior to the removal of the support bath. To this aim, genipin, chosen as crosslinking agent, was added (0.1 wt.%) to collagen-based biomaterial inks (containing either 38 wt.% mesoporous bioactive glasses or 65 wt.% nanohydroxyapatite), to trigger the crosslinking of collagen and improve the stability of the 3D printed scaffolds in the post-processing step. Moreover, to support the material deposition, a 15 wt.% alginic acid solution was used as a bath, which proved to sustain the printed structures and was also easily removable, allowing for the stable processing of high-resolution geometries

Cesium and strontium tolerant Arthrobacter sp. strain KMSZP6 isolated from a pristine uranium ore deposit

Additional file 3: Figure S3 Radiation tolerance of A. nicotinovorans. Exponential phase cells (OD600 nm 1.0) were exposed to gamma radiation from 60Co source. Volumes of 10 ÂľL from a dilution series of the irradiated cell culture were spotted on LPM agar plates and incubated under usual growth conditions. The cells tolerated upto 1 kGy 60Co-gamma rays without loss of survival

Insights in the exhumation history of the NWZagros frombedrock and detrital apatite fission-track analysis: evidence for a long-lived orogeny

We present the ¢rst ¢ssion-track (FT) thermochronology results for theNWZagrosBelt (SWIran) in order to identify denudation episodes that occurred during the protracted Zagros orogeny. Samples were collected from the two main detrital successions of the NWZagros foreland basin: the Palaeocene^early Eocene Amiran^Kashkan succession and theMiocene Agha Jari and Bakhtyari Formations. In situ bedrock samples were furthermore collected in the Sanandaj-Sirjan Zone. Only apatite ¢ssion-track (AFT) data have been successfully obtained, including 26 ages and11track-length distributions. Five families of AFTages have been documented from analyses of in situ bedrock and detrital samples: pre-middle Jurassic at 171 and 225Ma, early^late Cretaceous at 91Ma, Maastrichtian at 66Ma,middle^late Eocene at 38Ma and Oligocene^early Miocene at 22Ma.The most widespread middle^late Eocene cooling phase, around 38Ma, is documented by a predominant grain-age population in Agha Jari sediments and by cooling ages of a granitic boulder sample. AFTages document at least three cooling/denudation periods linked to major geodynamic events related to the Zagros orogeny, during the lateCretaceous oceanic obduction event, during the middle and late Eocene and during the earlyMiocene. Both late Cretaceous and early Miocene orogenic processes produced bending of the Arabian plate and concomitant foreland deposition. Between the two major £exural foreland episodes, the middle^late Eocene phase mostly produced a long-lasting slow- or nondepositional episode in the inner part of the foreland basin, whereas deposition and tectonics migrated to theNE along the Sanandaj-Sirjan domain and its Gaveh Rud fore-arc basin. As evidenced in this study, the Zagros orogeny was long-lived and multiepisodic, implying that the timing of accretion of the di¡erent tectonic domains that form the Zagros Mountains requires cautious interpretation

Algar do Bom Santo: a research project on the Neolithic populations of Portuguese Estremadura (6th-4th millennia BC)

O presente artigo tem como propósito a apresentação do conteúdo, âmbito e objectivos do projecto de investigação consignado ao estudo da gruta-necrópole neolítica do Algar do Bom Santo (freguesia da Abrigada, concelho de Alenquer). Quando pertinentes, incluem-se também breves descrições preliminares dos resultados dos trabalhos de campo realizados neste sítio pela Dra. Cidália Duarte entre 1994 e 2001. No seu essencial, o texto que se segue corresponde à componente técnico-científica do projecto submetido a financiamento à Fundação para a Ciência e a Tecnologia, razão pela qual, aliás, se encontra redigido em língua inglesa. As principais alterações tiveram em vista a introdução de um maior desenvolvimento das diversas partes que compunham o conjunto da candidatura, assim como o seu encadeamento numa sequenciação lógica. Acrescentou-se ainda uma bibliografia mais completa e algumas fotografias obtidas aquando dos referidos trabalhos de campo

Strontium studies in children

The localisation of radio-active strontium within the bona matrix of the young animal has given rise to a modern hazard unknown before the advent of thermonuclear explosions and fallout. The metabolism of this element has been investigated by many workers but results for work on children are somewhat limited. This thesis describes a series of measurements in hospitalised children during which the stable isotope of strontium was determined in various samples using a spectrochemical method. The relative calcium content of these samples was also estimated by this means. Optimum working conditions for the instrument were first obtained and are detailed in the text. The variation of urinary calcium content in ageing samples has been studied and found to be minimised by acidification. A group of nine strontium-calcium balances under additional calcium are described and the effect of the salicylate ion considered. This appears to be dependent on the calcium salt employed. The strontium content of some 45 samples of children's urine has been determined using a direct method which emits the separation of the strontium. Strontium/calcium ratios for those samples have also been calculated and found to occupy a considerable range in value. One sample of urinary calculus has been investigated and is shown to differ markedly from the urine of the same patient. Values for natural strontium/calcium in bone and teeth have been determined and found to be reasonably comparable, giving rise to O. R. bone or teath/diet of 0,25 (approx.). One case of osteogenic sarcoma is described showing the uptake of strontium in both the tumour and surrounding tissue. Balances in rachitic children suggest that vitamin D, produces an increased absorption of calcium but not of strontium. Studies in infants on milk diets indicate that the O.R. bone/diet is higher then in older children or adults, which suggest a lower discrimination in favour of calcium in infants. A large variation in O.R. urine/ diet is also exhibited in this age group. Throughout this thesis, various interlaboratory comparisons of results are given, as are comparison of results obtained on the same sample by different methods. The above results have awakened many questions which it is hoped to answer in further research

The mitochondrial phosphate carrier: Role in oxidative metabolism, calcium handling and mitochondrial disease

The mitochondrial phosphate carrier (PiC) is a mitochondrial solute carrier protein, which is encoded by SLC25A3 in humans. PiC delivers phosphate, a key substrate of oxidative phosphorylation, across the inner mitochondrial membrane. This transport activity is also relevant for allowing effective mitochondrial calcium handling. Furthermore, PiC has also been described to affect cell survival mechanisms via interactions with cyclophilin D and the viral mitochondrial-localized inhibitor of apoptosis (vMIA). The significance of PiC has been supported by the recent discovery of a fatal human condition associated with PiC mutations. Here, we present first the early studies that lead to the discovery and molecular characterization of the PiC, then discuss the very recently developed mouse models for PiC and pathological mutations in the human SLC25A3 gene. © 2015