Collagenated Porcine Heterologous Bone Grafts: Histomorphometric Evaluation of Bone Formation Using Different Physical Forms in a Rabbit Cancellous Bone Model

Collagenated porcine-derived bone graft materials exhibit osteoconductive properties and the development of different formulations intends to enhance bone regeneration. This study aims to evaluate bone healing in a rabbit cancellous bone defect in response to grafting with different physicochemical forms of heterologous porcine bone. Twenty-six adult male New Zealand White rabbits received two critical size femoral bone defects per animal (n = 52), each randomly assigned to one of the five tested materials (Apatos, Gen-Os, mp3, Putty, and Gel 40). Animals were sacrificed at 15- and 30-days post-surgery. Qualitative and quantitative (new bone, particle and connective tissue percentages) histological analyses were performed. Histomorphometry showed statistically significant differences in all evaluated parameters between mp3 and both Putty and Gel 40 groups, regardless of the timepoint (p < 0.05). Moreover, statistical differences were observed between Apatos and both Putty (p = 0.014) and Gel 40 (p = 0.007) groups, at 30 days, in regard to particle percentage. Within each group, regarding new bone formation, mp3 showed significant differences (p = 0.028) between 15 (40.93 ± 3.49%) and 30 (52.49 ± 11.04%) days. Additionally, intragroup analysis concerning the percentage of particles revealed a significant reduction in particle occupied area from 15 to 30 days in mp3 and Gen-Os groups (p = 0.009). All mp3, Gen-Os and Apatos exhibited promising results in terms of new bone formation, thus presenting suitable alternatives to be used in bone regeneration.     

Synthesis of a New Series of Bone Affinity Compounds

As known that tetracycline possesses bone affinity1, which can be used as carrier of bone-targeting drugs. Chrysophanol is one of the anthraquinone components isolated from Rheum palmatum L., its structure is similar to tetracycline. The bone affinity of …     

骨铅含量应作为人体铅中毒新的生物标记

综述了人体铅含量的危害,血铅检测的局限性以及骨铅检测的必要性和检测技术研究进展。认为国内应该加强相关的研究,早日将骨铅含量作为人体铅中毒新的生物标记。     

Chicken Bone as a Bioresource for the Bioceramic (Hydroxyapatite)

Natural hydroxyapatite (HAP) is isolated from waste chicken bone by thermal calcinations at different temperatures in the range of 200 °C to 1000 °C. The isolated HAP has been characterized using thermo gravimetric analysis (TG) and differential thermal analysis (DTA), Fourier Transformed Infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission electron microscope (FE-SEM), and energy dispersive X-ray (EDX). The XRD results showed that the enhanced crystallinity of HAP phase by thermal calcination above 600 °C and the crystal size has been found to increase with increasing temperature of thermal calcinations due to agglomeration. Value addition for the waste chicken bone is given by the isolation of useful bioceramics (HAP) and the optimum temperature for the thermal calcination is found to be 600 °C. The isolated HAP has been characterized as carbonated HAP of B type with the hexagonal structure. These results will not only make the chicken bone as an important bioresource for the HAP but will also reduce the environmental pollution caused by dumping of the waste chicken bone.     

Bone collagen cross-links: a convergent synthesis of (+)-deoxypyrrololine.

A convergent total synthesis of (+)-deoxypyrrololine (Dpl, 4), a putative cross-link of bone collagen, is described starting from a commercially available L-glutamic acid derivative, (4S)-5-(tert-butoxy)-4-[(tert-butoxycarbonyl)amino]-5- oxopentanoic acid (16). Condensation of aldehyde (S)-(-)-17 with nitro compound (S)-(-)-27, both of which were prepared from a common precursor (S)-16, gave the alpha-hydroxynitro compound 28, which upon acetylation afforded alpha-acetoxynitro compound 14 in good yield. Subsequent condensation and cyclization of alpha-acetoxynitro compound 14 with benzyl isocyanoacetate (15) in the presence of DBU in THF gave the key pyrrole intermediate (S,S)-(-)-12 in 57% yield. N-Alkylation of pyrrole (S,S)-(-)-12 with iodide (S)-(-)-13 using t-BuOK in THF afforded the 2-benzyloxycarbonyl-1,3,4-substituted pyrrole derivative (-)-29 in 42% yield. Removal of the protective groups in (-)-29 followed by hydrogenolysis and decarboxylation afforded the cross-link (+)-Dpl (4) in good overall yield. The synthesis of an analogue (S)-(+)-24 and formation of a novel tetrahydroindole derivative (-)-31 are also described.     

Reduced Bone Mineral Density and Bone Metabolism in Aquaporin-1 Knockout Mice

An overt phenotype of aquaporin-1 knockout(AQP1 ko) mice is growth retardation, suggesting possible defects in bone development and metabolism. In the present study, we analyzed the bone mineral density(BMD), bone calcium and phosphorus contents, and bone metabolism in an AQP1 ko mouse model. The BMD of femurs in AQP1 ko mice was significantly lower than that of litter-matched wildtype mice as measured by dual energy X-ray absorptiometry. Consistently, the contents of bone total calcium and phosphorus were also significantly lower in AQP1 ko mice. The reduced BMD caused by AQP1 deficiency mainly affect male mice. Bone metabolic activity, as indicated by 99mTc-MDP absorption measurements, was remarkably reduced in AQP1 ko mice. These results provide the first evidence that AQP1 play an important role in bone structure and metabolism.     

On a Pure Instrumental Method of 90Sr Determination in Bone Samples

An attempt is presented for the measurement of ⁹⁰Sr in real animal bone samples using gamma-ray spectrometry only with germanium detector. Gamma-ray spectra of bone samples are de-convoluted and the residue bremsstrahlung effect from ⁹⁰Sr-⁹⁰Y beta-radiation is observed. The validation of the proposed method was done by standard ⁹⁰Sr determination including radiochemical separation and liquid scintillation spectrometry (LSS). The Pearson correlation factor obtained between the activity determined by LSS and the proposed instrumental method was 0.57, with the achieved efficiency of 0.12%. Possible improvements of the method are suggested.     

An Acid-Activatable Fluorescence Probe for Imaging Osteocytic Bone Resorption Activity in Deep Bone Cavities

A rationally designed pH-activatable fluorescent probe (pHocas-RIS) has been used to measure localised pH levels in osteocytic lacunae in bone tissue. Conjugation of the moderate bone-binding drug risedronate to a pH-activatable BODIPY fluorophore enables the probe to penetrate osteocytic lacunae cavities that are embedded deep within the bone matrix. After injection of pHocas-RIS, any osteocytic lacunae caused by bone-resorbing osteocytes cause the probe to fluoresce in vivo, thus allowing imaging by intravital two-photon excitation microscopy. This pH responsive probe enabled the visualization of the bone mineralizing activities of acid producing osteocytes in real time, thus allowing the study of their central role in remodeling the bone-matrix in healthy and disease states.     

Design and Assessment of a Dynamic Perfusion Bioreactor for Large Bone Tissue Engineering Scaffolds

Bioreactors can be used to apply fluid flow in vitro to scaffolds to improve mass transport of media and apply mechanical forces to cells. In this study, we developed and tested an autoclavable, modular perfusion bioreactor suitable for large scaffolds. We investigated the effects of fluid flow induced shear stress (FFSS) on osteogenic differentiation of human embryonic stem cell-derived mesenchymal progenitors (hES-MP cells) cultured on large polyurethane (PU) scaffolds (30 mm diameter × 5 mm thickness) in osteogenesis induction media (OIM). After seeding, scaffolds were either maintained in static conditions or transferred to the bioreactor 3 days post-seeding and a continuous flow rate of 3.47 mL/min was applied. Alkaline phosphatase activity (ALP) was used to evaluate osteogenic differentiation and resazurin salt reduction (RR) to measure metabolic activity after 10 days. Cultures subjected to flow contained significantly more metabolically active cells and higher total DNA content, as well as significantly higher ALP activity compared to scaffolds grown in static culture. These results confirm the responsiveness of hES-MP cells to fluid flow stimuli, and present a cost-effective, user-friendly bioreactor capable of supporting the growth and differentiation of mesenchymal progenitor cells within scaffolds capable of filling large bone defects.     

Radiotracers for Bone Marrow Infection Imaging

Introduction: Radiotracers are widely used in medical imaging, using techniques of gamma-camera imaging (scintigraphy and SPECT) or positron emission tomography (PET). In bone marrow infection, there is no single routine test available that can detect infection with sufficiently high diagnostic accuracy. Here, we review radiotracers used for imaging of bone marrow infection, also known as osteomyelitis, with a focus on why these molecules are relevant for the task, based on their physiological uptake mechanisms. The review comprises [⁶⁷Ga]Ga-citrate, radiolabelled leukocytes, radiolabelled nanocolloids (bone marrow) and radiolabelled phosphonates (bone structure), and [¹⁸F]FDG as established radiotracers for bone marrow infection imaging. Tracers that are under development or testing for this purpose include [⁶⁸Ga]Ga-citrate, [¹⁸F]FDG, [¹⁸F]FDS and other non-glucose sugar analogues, [¹⁵O]water, [¹¹C]methionine, [¹¹C]donepezil, [^99mTc]Tc-IL-8, [⁶⁸Ga]Ga-Siglec-9, phage-display selected peptides, and the antimicrobial peptide [^99mTc]Tc-UBI_29-41 or [⁶⁸Ga]Ga-NOTA-UBI_29-41. Conclusion: Molecular radiotracers allow studies of physiological processes such as infection. None of the reviewed molecules are ideal for the imaging of infections, whether bone marrow or otherwise, but each can give information about a separate aspect such as physiology or biochemistry. Knowledge of uptake mechanisms, pitfalls, and challenges is useful in both the use and development of medically relevant radioactive tracers.     

Self-Hardening Hydrogel for Bone Tissue Engineering

Summary: We have developed a self-reticulating polymer based on silanized hydroxypropylmethylcellulose (Si-HPMC). The aim of this study was to determine whether this Si-HPMC hydrogel with or without calcium phosphate granules could represent a potential scaffold for bone tissue engineering. This study showed that Si-HPMC hydrogel didn't affect SaOS-2 and rat bone marrow cells viability. In addition, SaOS-2 cells are able to proliferate within Si-HPMC hydrogel containing or not calcium phosphate granules whereas Rat bone marrow cells proliferate only at the surface of calcium phosphate granules contained within Si-HPMC hydrogel. Finally, SaOS-2 cells seeded at the surface of reticulated Si-HPMC were not able to penetrate the hydrogel, while J774, a macrophage cells line, were able to move into the Si-HPMC hydrogel. These data indicate that Si-HPMC is a promissing scaffold for tissue engineering.     

有机-无机杂化骨修复材料

寻找理想的骨修复材料一直是骨科领域的研究热点之一。骨修复材料已由最初单纯取代天然骨组织的惰性材料向具有诱导骨组织再生功能的生物活性材料发展,其中有机-无机杂化材料由于有机和无机组分在分子/纳米水平的复合使其能够最大程度地实现二者的优势互补和协同优化,近年来受到广泛关注。本文着重介绍了有机-无机杂化骨修复材料近些年来的研究进展,并对其发展趋势进行了展望。     

骨的微量元素代谢

雌激素可通过影响骨骼细胞的新陈代谢而促进微量元素在骨骼中的储存,微量元素代谢与骨质疏松的形成发展有密切关系。近年来不少学者对一些必需微量元素如硼(5B)、氟(9F)、钒(23V)、锰(25Mn)、铁(26Fe)、钴(27Co)、铜(29Cu)、锌(30Zn)、硒(34Se)、锶(38Sr)等和一些非必需微量元素如铝(13Al)、镓(31Ga)、锗(32Ge)、镉(48Cd)、铅(82Pb)等与骨质疏松关系的研究取得了令人瞩目的成果。     

Bone fluoride in chronically uremic rats

The whole-body clearance of¹⁸F-fluoride injected intravenously into chronically uremic rats was found to proceed more slowly (7.6% of the dose in the first hour, vs 28%) and to a lesser total amount (18.5% vs 46.7%) in 4 hrs than in normal rats of the same age. The concentration of radiofluoride in the urine of uremies during the first hour was about 10% of that observed in normals. No changes in²⁴Na and⁴²K whole-body clearance rates were detected in this surgically-induced model of chronic uremia. Statistically significant elevations in central compartment fluoride concentrations were observed 4 hrs after injection. Fluorine and calcium in bones of uremic and normal animals were measured using Instrumental Neutron Activation Analysis techniques. The ratios μg F/mg Ca were highly significantly greater in uremics (2.2±0.3 vs 1.1±0.3). These differences were primarily brought about by elevations in bone fluoride rather than by decreases in calcium content of the uremic bone.     

Decellularized Periosteum‐Covered Chitosan Globule Composite for Bone Regeneration in Rabbit Femur Condyle Bone Defects

Critical‐sized bone defects are incapable of self‐healing and are commonly seen in clinical practice. The authors explore a new treatment for this, decellularized periosteum is applied to chitosan globules (chitosan‐DP globules) as a hybrid material. The efficacy of chitosan‐DP globules on rabbit femoral condyle bone defects is assessed with biocompatibility, biomechanics, and osteogenic efficiency measurements, and compared with the results of chitosan globules and empty control. No difference in cytotoxicity is observed among chitosan‐DP globules, chitosan globules, and the empty control. Chitosan‐DP globules possesse a better surface for cell adhesion than did chitosan globules. Chitosan‐DP globules demonstrate superior efficiency for osteogenesis in the defect area compared to chitosan globules as per microcomputed tomography examination and push‐out testing, with relatively minor histological differences. Both chitosan globule groups show more satisfactory results than those for the empty control. The results implicate chitosan‐DP globules as a promising solution for bone defects.     

去卵巢大鼠骨基质明胶修复骨缺损骨痂的矿物质元素分析

应用等离子体发射光谱仪测定了去卵巢水平下骨基质明胶修复大鼠颅骨骨缺损新生骨痂的矿物质元素含量。将28只雌性SD大鼠随机分为2组。去卵巢组切除双侧卵巢，伪手术对照组保留卵巢。术后4周在颅骨上制备骨缺损并同期植入骨基质明胶。8周后，测定新生骨痂的矿物质元素含量。结果显示，去卵巢大鼠新生骨痂的S、Ca、P、Zn、Fe和Cu含量较伪手术组显著降低。实验表明雌激素水平影响骨基质明胶修复骨缺损骨痂的矿物质元素含量。     

骨及生物材料中的纳米磷酸钙

纳米磷酸钙在自然界骨组织的形成过程中起到了关键作用。尽管骨的类型有所不同,但在其初级结构中的无机成分都是纳米磷酸钙。纳米磷酸钙结构能够给予骨良好的机械性能和生物学活性。在生物体中,无机纳米磷酸钙在有机基质的调控下能定向自组装成特定的生物矿物。体外细胞实验显示小尺寸纳米羟基磷灰石更能促进骨髓基质干细胞的增殖,而同尺寸的结晶型纳米磷酸钙则比无定形磷酸钙更能利于干细胞分化。鉴于纳米磷酸钙具有很好的生物相容性和骨诱导性,可以发展成为理想的生物材料常用于骨组织工程和生物医学。