Fabrication of 3D Bioprinted Bi-Phasic Scaffold for Bone-Cartilage Interface Regeneration.

Treatments for osteochondral defects (OCDs) are mainly palliative and, with the increase in this pathology seen among both young and elderly people, an alternative treatment modality is sought. Many tissue-engineered strategies have been explored for regenerating the cartilage-bone interface; however, they generally fall short of being ideal. Although cell-laden hydrogel scaffolds are a common approach for bone and cartilage tissue regeneration, they usually lack homogenous cell dispersion and patient specificity.

Dual Network Composites of Poly(vinyl alcohol)-Calcium Metaphosphate/Alginate with Osteogenic Ions for Bone Tissue Engineering in Oral and Maxillofacial Surgery.

Despite considerable advances in biomaterials-based bone tissue engineering technologies, autografts remain the gold standard for rehabilitating critical-sized bone defects in the oral and maxillofacial (OMF) region. A majority of advanced synthetic bone substitutes (SBS's) have not transcended the pre-clinical stage due to inferior clinical performance and translational barriers, which include low scalability, high cost, regulatory restrictions, limited advanced facilities and human resources. The aim of this study is to develop clinically viable alternatives to address the challenges of bone tissue regeneration in the OMF region by developing 'dual network composites' (DNC's) of calcium metaphosphate (CMP)-poly(vinyl alcohol) (PVA)/alginate with osteogenic ions: calcium, zinc and strontium.

Structural changes and biological responsiveness of an injectable and mouldable monetite bone graft generated by a facile synthetic method.

Brushite (dicalcium phosphate dihydrate) and monetite (dicalcium phosphate anhydrous) are of considerable interest in bone augmentation owing to their metastable nature in physiological fluids. The anhydrous form of brushite, namely monetite, has a finer microstructure with higher surface area, strength and bioresorbability, which does not transform to the poorly resorbable hydroxyapatite, thus making it a viable alternative for use as a scaffold for engineering of bone tissue. We recently reported the formation of monetite cements by a simple processing route without the need of hydrothermal treatment by using a high concentration of sodium chloride in the reaction mix of β-tricalcium phosphate and monocalcium phosphate monohydrate.

In vitro proliferation and differentiation of human mesenchymal stem cells on hydroxyapatite versus human demineralised bone matrix with and without osteogenic protein-1.

Background: Allografting is currently used in lower limb reconstruction surgery. Demineralised bone matrix (DBM) is more osteoinductive compared with allografts but lacks mechanical strength. Osteogenic protein-1 (OP-1) can improve the osteoinductivity of the allograft, however recent reports indicate significant allograft resorption when it is combined with OP-1.

PMMA bone cement containing a quaternary amine comonomer with potential antibacterial properties.

An iodinated quaternary amine dimethacrylate monomer was synthesized and incorporated as a comonomer in acrylic bone cements. Bone cement is used in orthopaedic surgery and imparting antibacterial properties to the cement can be beneficial in the lowering of bacterial infection post surgery. PMMA based bone cements were modified by copolymerising the monomer methylmethacrylate (MMA) with a quaternary amine dimethacrylate by using the redox initiator activator system as used for curing commercial bone cements.

In vitro and in vivo optimization of impaction allografting by demineralization and addition of rh-OP-1.

Impaction allografting is a bone tissue engineering technique currently used in lower limb reconstruction orthopedic surgery. Our hypothesis was that biological optimization can be achieved by demineralization and addition of osteogenic protein-1 (OP-1) to the allograft. The objective of our in vitro study was to evaluate human mesenchymal stem cell (MSC) proliferation (Alamar Blue assay, titrated thymidine assay, total DNA Hoechst 33258, and scanning electron microscopy) and osteogenic differentiation (alkaline phosphatase assay) in two types of impacted carrier, namely, demineralized bone matrix (DBM) and insoluble collagenous bone matrix (ICBM), with or without OP-1.

In vitro evaluation of the direct effect of estradiol on human osteoblasts (HOB) and human mesenchymal stem cells (h-MSCs).

Estrogen may increase the proliferation of osteoblasts depending upon their differentiation stage. Our objective was to test the hypothesis that estradiol could stimulate the proliferation of primary human osteoblast (HOB) cells or human mesenchymal stem cells (h-MSCs). To test this hypothesis, we investigated two synthetic estradiol preparations: (a) a commercially available one (in clinical use) whose effect was evaluated using MTT assay, trypan blue cell counts and total protein assays; (b) a novel synthetic preparation (not in clinical use) using Alamar Blue assays and scanning electron microscopy (SEM).

In vitro cellular response to titanium electrochemically coated with hydroxyapatite compared to titanium with three different levels of surface roughness.

The in vitro response of primary human osteoblast-like (HOB) cells to a novel hydroxyapatite (HA) coated titanium substrate, produced by a low temperature electrochemical method, was compared to three different titanium surfaces: as-machined, Al(2)O(3)-blasted, plasma-sprayed with titanium particles. HOB cells were cultured on different surfaces for 3, 7 and 14 days at 37 degrees C. The cell morphology was assessed using scanning electron microscopy (SEM).

The determination of detection limits for insulin antibody assays.

In order to define the detection limit of a radioimmunoassay for insulin-antibody a correction was made for binding in the presence of an excess of unlabelled insulin and assay precision was calculated. One hundred forty control sera were assessed; all were islet cell antibody negative. For each sample, binding of 125-I human insulin was determined both with and without excess unlabelled insulin, subtraction of the latter acting as a correction.

Influence of aging on hepatic and peripheral glucose metabolism in humans.

Mechanisms of glucose intolerance with aging were studied by comparing the metabolic response to glucose ingestion in 10 young (20-23 yr) and 10 elderly (73-80 yr) normal men with the simultaneous application of the forearm and double-isotope techniques. The latter technique consisted of a primed-constant infusion of [3-3H]glucose followed by the administration of an oral glucose load (mean +/- SE, 90.7 +/- 0.

Mechanism of metformin action in non-insulin-dependent diabetes.

The mechanism of action of metformin was studied by comparing glucose turnover before and after a 75-g oral glucose load in 10 nonobese men with non-insulin-dependent diabetes mellitus (NIDDM) during metformin and placebo therapy by the combined application of the forearm and double-isotope techniques. During the study, 9 of the 10 patients were regularly receiving glibenclamide therapy. In 5 of the men, the first study was performed during metformin therapy, and the second study was done during placebo administration; in the other 5 subjects, the order was reversed.

Impact of glucose ingestion on hepatic and peripheral glucose metabolism in man: an analysis based on simultaneous use of the forearm and double isotope techniques.

The metabolic response to glucose ingestion was studied in 10 normal men (aged 21-23 yr) by the simultaneous application of the forearm and double isotope techniques. The latter consisted of a primed constant infusion of [3-3H]glucose, followed by the administration of an oral glucose load (mean +/- SE, 90.7 +/- 0.